• 专利附录
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    • 专利摘要:
    IMAGE FORMATING APPLIANCE The image forming device can be used in areas with different power supply voltages, in which a device failure can be detected so that the device's reliability is improved. The device includes a connection state switching part that switches connection between a first heat generating element and a second heat generating element, which generate heat by electrical energy supplied from a commercial power source via a supply path. between a serial connection state and a parallel connection state, and a current detection part that detects current flowing in the power supply path. The current detection part is arranged in the energy supply path after branching towards the first heat generating element and the second heat generating element in the state of constant connection.
    公开号:BR112012021667B1
    申请号:R112012021667-8
    申请日:2011-03-16
    公开日:2021-01-12
    发明作者:Yasuhiro Shimura
    申请人:Canon Kabushiki Kaisha；
    IPC主号:
    专利说明:

    [0001] [0001] The present invention relates to an image forming apparatus such as a copier or a laser beam printer, and particularly to an image forming apparatus including a fixation part that securely fixes an image formed on a material recording for the recording material. Background art
    [0002] [0002] When an imaging device for an area where the commercial power supply voltage is a 100 V system (for example, 100 V to 127 V) is used in an area where the commercial power supply voltage it is a 200 V system (for example, 200 V at 240 v), the maximum power that can be supplied to a heater of a fixation part (fixation device) of the image formation device becomes four times as big. If the maximum power that can be supplied to the heater increases, harmonic current, sparks, and the like generated in the control of the heater's electrical energy such as phase control or control of the number of waves become conspicuous. In addition, as the electrical energy generated when the fixing device presents thermal shock without normal operation increases by four times, it is necessary to have a safety circuit with faster response. Therefore, when the same imaging device is used in areas where the commercial power supply voltage is 100 V and where the commercial power supply voltage is 200 V, it is common to use individual heaters having different resistance values for the respective replacement areas.
    [0003] [0003] On the other hand, as a means of making a universal device that can be used in both areas where the commercial power supply voltage of 100 v is supplied and where the commercial power supply voltage of 200 V is provided, a method is proposed that involves switching the resistance value of the heater using a switching unit such as a relay. In patent literature 1 and 2, a device is proposed that can be used in both areas where the commercial power supply voltage is 100 V and where the commercial power supply voltage is 200 V. The device includes a first element heat generating element and a second heat generating element, and can switch between a first operating state in which the first heat generating element and the second heat generating element are connected in series and a second operating state in which the first heat generating element and the second heat generating element are connected in parallel, thereby switching the resistance value of the heat generating element according to the commercial power supply voltage. List of citations Patent literature:
    [0004] [0004] PTL 1: Japanese patent application no. HO7-199702
    [0005] [0005] PTL 2: US patent no. 5,229,577 Summary of the invention Technical problem
    [0006] [0006] The method involving switching between the serial connection state and the parallel connection state of the first heat generating element and the second heat generating element according to the commercial power supply voltage allows to switch the value of heater resistance without changing a heater heat generation region. In other words, the two heat generating elements generate heat when the device is used in any of the 100 V and 200 V areas. The aforementioned method involving switching between the serial connection and the parallel connection is effective particularly in the clamping device including an endless belt, a heater that is placed in contact with an internal surface of the endless belt, and a pressure roller that forms a fastening nip part with the heater through the endless belt. This is because the two heat generating elements generate heat when the device is used in any of the 100 V and 200 V areas so that the temperature distribution in the direction of transferring recording material in the clamping narrowing part is the same regardless of the area where the device is used. Therefore, there is merit that the fixing performance of a toner image is not affected by the area where the machine is used.
    [0007] [0007] However, the aforementioned method can cause a state in which excess electrical power can be supplied to the heater when a power supply voltage sensing part or a resistance value switching relay fails. For example, if the parallel connection state in which the heater resistance value is low is set to the state in which the imaging device is connected to the 200 v commercial power source, the electrical power which is four times greater than that in the normal state can be supplied to the heater. As the electrical power supplied to the heater becomes too large, the safety circuit using a temperature sensing element such as a thermistor, thermal fuse, or thermal switch may be insufficient in response speed to cut off the power supply. for the heater. Therefore, in the device that can switch the resistance value, it is necessary to detect a fault state in which large electrical power can be supplied to the heater by another method than the method of detecting temperature.
    [0008] [0008] An objective of the present invention is to provide an image forming apparatus capable of detecting a failure of the apparatus, in which connection of a first heat generating element and a second heat generating element can be switched between a state of serial connection and a parallel connection state. Solution to the problem
    [0009] [0009] To solve the aforementioned problem, an image forming apparatus according to the present invention includes:
    [0010] [0010] A fixing part including a first heat generating element and a second heat generating element that generate heat by electrical energy supplied from a commercial energy source through an energy supply path to heat fix an image formed in a recording material in the recording material;
    [0011] [0011] A connection state switching part that switches connection of the first heat generating element and second heat generating element between a serial connection state and a parallel connection state; and
    [0012] [0012] A current detection part that detects a current flowing in the energy supply path,
    [0013] [0013] In which the current detection part is arranged in the energy supply path after branching towards the first heat generating element and second heat generating element in the parallel connection state.
    [0014] [0014] In addition, an image forming apparatus according to the present invention includes:
    [0015] [0015] A fixing part including a first heat generating element and a second heat generating element that generate heat by electrical energy supplied from a commercial energy source through an energy supply path to heat fix an image formed in a recording material in the recording material;
    [0016] [0016] A connection state switching part that switches connection of the first heat generating element and second heat generating element between a serial connection state and a parallel connection state; and
    [0017] [0017] A current detection part that detects a voltage, in which the voltage detection part is arranged in order to detect one of a voltage generates the two ends of the first heat generating element and a voltage generates both ends of the second heat generating element in the state of serial connection. Advantageous effects of the invention
    [0018] [0018] According to the present invention, it is possible to detect the failure of the device, in which the connection of the first heat generating element and the second heat generating element can be switched between the serial connection state and the state of parallel connection.
    [0019] [0019] Additional aspects of the present invention will become evident from the following description of exemplary modalities with reference to the attached drawings. Brief description of the drawings
    [0020] [0020] Figure 1 illustrates a cross section of an image heating device of the present invention.
    [0021] [0021] Figure 2A illustrates a structure of a heater control circuit of a first mode.
    [0022] [0022] Figure 2B illustrates a circuit of a voltage sensing part of the heater control circuit of the first mode.
    [0023] [0023] Figure 3A is a diagram that illustrates an external structure of a heater in the first modality.
    [0024] [0024] Figure 3B is a diagram that illustrates the heater in a first operational state in which a power supply voltage is 200 V in the first mode.
    [0025] [0025] Figure 3C is a diagram that illustrates the heater in a second operational state in which the power supply voltage is 100 V in the first mode.
    [0026] [0026] Figure 4A is a diagram that illustrates the heater in the second operational state in which the power supply voltage is 200 V in the first mode.
    [0027] [0027] Figure 4B is a diagram illustrating the heater in a state in which the power supply voltage is 200 V, RL1 is in the ON state, and RL2 is in the OFF state in the first mode.
    [0028] [0028] Figure 4C is a diagram that illustrates the heater in a state in which the power supply voltage is 200 V, RL1 is in the OFF state, and RL2 is in the ON state in the first mode.
    [0029] [0029] Figure 5A is a flowchart of control of the first modality. Figure 5 is comprised of figures 5A and 5B.
    [0030] [0030] Figure 5B is a control flow chart of the first modality. Figure 5 is comprised of figures 5A and 5B.
    [0031] [0031] Figure 6 illustrates a structure of a heater control circuit of a second mode.
    [0032] [0032] Figure 7 illustrates a structure of a heater control circuit of a third modality.
    [0033] [0033] Figure 8A is a diagram illustrating an external structure of a heater of the third modality.
    [0034] [0034] Figure 8B is a diagram that illustrates the heater in the first operational state in which the power supply voltage is 200 V in the third mode.
    [0035] [0035] Figure 8C is a diagram that illustrates the heater in the second operating state in which the power supply voltage is 100 V in the third mode.
    [0036] [0036] Figure 8D is a diagram that illustrates the heater in the operational state in which the power supply voltage is 200 V in the third mode.
    [0037] [0037] Figure 9 is a schematic diagram of an image-forming device. Description of modalities
    [0038] [0038] In the following, exemplary embodiments of the present invention are described in detail with reference to the attached drawings. First modality
    [0039] [0039] Figure 9 is a cross-sectional view of an image-forming device (full color printer in this mode) using an electrophotography. An image forming part that forms a toner image on a recording material P includes four image forming stations (1Y, 1M, 1C and 1Bk). Each of the imaging stations includes a photosensitive element 2 (2a, 2b, 2c or 2d), a charge element 3 (3a, 3b, 3c, or 3d), a laser scanner 7 (7a, 7b, 7c or 7d ), a developing device 4 (4a, 4b, 4c or 4d), a transfer element 5 (5a, 5b, 5c or 5d) and cleaning means 6 (6a, 6b, 6c or 6d) that cleans the element photosensitive. In addition, the imaging part includes a belt 9 that contains and transfers a toner image, and a secondary transfer roller 8 that transfers the toner image from belt 9 to recording material P. the action of the image formation described above is well known, and consequently its description is omitted. The recording material P in which the unfixed toner image is transferred in the image forming part is transferred to a fixing part 100 in which the toner image is heat fixed in the recording material P.
    [0040] [0040] Figure 1 is a cross-sectional view of the fixing device (fixing part) 100 that heat-fixes the image on the recording material to the recording material. The fixing device 100 includes a film (endless belt) 102 wound in a cylindrical shape, a heater 300 which is placed in contact with an internal surface of the film 102, and a pressure roller (nip part forming element) 108. The pressure roller 108 and the heater 300 together form a fixing narrowing part N through the film 102. The film 102 has a base layer made of a heat resistant resin such as a polyimide or a metal such as stainless. Pressure roller 108 includes a core metal 109 made of iron, aluminum or the like and an elastic layer 110 made of silicone rubber or the like. The heater 300 is held by a retainer 101 made of a heat resistant resin. The retaining element 101 also has a guide function to guide the rotation of the film 102. The pressure roller 108 is driven by a motor (not shown) and rotated in a direction of the arrow. Along with the rotation of the pressure roller 108, the film 102 is rotated following the rotation of the pressure roller 108.
    [0041] [0041] The heater 300 includes a heater substrate 105 made of ceramic, a first heat generating element H1 and a second heat generating element H2 each formed on the heater substrate by using a heat resistor, and a layer of surface protection 107 made of an insulating material (glass in this modality) covering the first heat generating element H1 and the second heat generating element H2. The heater substrate 105 has a rear surface formed as a sheet feed area for passing a sheet of minimum size (envelope size DL, which is 110 mm wide in this embodiment) defined as usable in a printer. A temperature sensing element 111 such as a thermistor abuts against the sheet feed area. According to the temperature detected by the temperature sensing element 111, energy to be supplied from a commercial alternating current (AC) energy source for the heater is controlled. The recording material (sheet) P to contain the unfixed toner image is subjected to fixation processing in the fixation narrowing part N, in which the recording material P is pressed and transferred while being heated. A security element 112 like a thermo-switch also abuts against the rear surface side of heater 105. Security element 112 is triggered when heater 300 experiences an abnormal temperature rise, and cuts off a power supply line (path power supply) to the heater. Similar to the temperature sensing element 111, the security element 112 also abuts against the sheet feeding area for the minimum size sheet. A metal rod 104 is employed to apply spring pressure (not shown) to the retainer 101.
    [0042] [0042] Figures 2A and 2B illustrate a control circuit 200 for heater 300 of the first mode. Figure 2A is a circuit block diagram illustrating control circuit 200, and figure 2B is a circuit diagram illustrating a voltage sensing part (power supply voltage sensing part) 202 and a detection part voltage (second voltage detection part) 207.
    [0043] [0043] Control circuit 200 is described with reference to figure 2A. Control circuit 200 includes connectors C1, C2, C3, C5 and C6 for connection between control circuit 200 and heater 300. Control circuit 200 also includes a commercial AC power source 201, and electrical control for the heater 300 is realized by turning on and off a triac TR1 (semiconductor drive device). The triac TR1 operates according to a heater activation signal from a CPU 203. The temperature detected by the temperature sensing element 111 is obtained as a split voltage from a pull-up resistor and CPU 203 is supplied as a TH signal. As an internal process of the 203 CPU, the electrical energy to be supplied is calculated, for example, by PI control based on the temperature detected by the temperature sensing element 111 and the set temperature of the heater 300, and the calculated result is converted into a level control as a phase angle (for phase control) or a wave number (for wave number control) in order to control the triac TR1 by the charge cycle ratio according to the control level.
    [0044] [0044] Below, a description is given of the power supply voltage detection part 202 that detects a voltage from the commercial power source 201, and a relay control part (control part) 204 that against a part of switching status (relays RL1 and RL2) according to the voltage detected by the power supply voltage detection part 202. Note that a detailed relay control sequence is described with reference to figures 5A and 5B.
    [0045] [0045] As illustrated in figure 2A, relays RL1, RL2, RL4 and RL5 are arranged. Figure 2A illustrates connection states of the relays in the OFF state of power supply of the image forming apparatus. Relays RL1 and RL2 function as the connection state switching part that switches connection of the first heat generating element H1 and second heat generating element H2 between a serial connection state and a parallel connection state. Note that RL1 is assumed to have a close contact or an open contact. In addition, RL2 is assumed to have a transfer contact. Thus, when the connection state switching part includes the relay RL1 having a close contact or an open contact, and the relay RL2 having a transfer contact, the necessary cost for the connection state switching part can be reduced.
    [0046] [0046] Relays RL4 and RL5 have a function of cutting off the power supply from the commercial power source 201 to heater 300. Relay RL4 becomes ON state simultaneously when the imaging device becomes a state reservation. In this state, the voltage sensing part 202 detects a voltage from the AC 201 power source. Note that the AC 201 power source has a first terminal and a second terminal, and that the triac TR1 is arranged in the power supply path. electrical from the second terminal of the commercial power source to the heater. The voltage detection part 202 determines whether a range of the power supply voltage (commercial voltage range) is a 100 V system (for example, 100 V to 127 V) or a 200 V system (for example, 200 V to 240 V), and transmits the voltage detection result as a VOLT signal to CPU 203 and relay control part 204. If the voltage range of the power source is the 200 V system, the VOLT signal becomes LOW (low) state. Details of the voltage sensing part 202 are described with reference to figure 2B.
    [0047] [0047] When the voltage detection part 202 detects 200 V, the relay control part 204 operates a lock part RL1 so that RL1 is kept in the OFF state (the state illustrated in figure 2A). Note that relay control part 204 is a safety circuit (hardware circuit) that is independent of CPU 203. When the lock part RL21 operates, RL1 maintains the OFF state even in the case where an RL1 on signal transmitted from CPU 203 becomes HIGH state. The relay control part 204 can operate in order to keep RL1 in the OFF state for a period when the VOLT signal is detected as being the LOW state, instead of operating like the lock circuit described above.
    [0048] [0048] On the other hand, CPU 203 maintains RL2 in the OFF state (the state illustrated in figure 2A) according to the voltage detection result by the voltage detection part 202 (detecting 200 V). In addition, when CPU 203 transmits an RL5 in the HIGH status signal in order to connect RL5, the state occurs in which the image heating device (fixture) 100 can be supplied with electrical power. In this state, the first heat generating element H1 and the second heat generating element H2 are connected in series. Therefore, heater 300 becomes the state in which the resistance value is high.
    [0049] [0049] When voltage detection part 202 detects 100 V, CPU 203 transmits signal RL1on of HIGH state so that relay control part 204 turns on RL1. On the other hand, CPU 203 transmits an RL2on signal of HIGH status according to the VOLT signal so that RL2 is turned on (to connect to the right contact). In addition, when CPU 203 transmits RL5 in the HIGH state signal in order to connect RL5, the state in which the image heating device 100 can be supplied with electrical power occurs. In this state, the first heat generating element H1 and the second heat generating element H2 are connected in parallel. Therefore, heater 300 becomes the state in which the resistance value is low.
    [0050] [0050] In the following, a current detection part 205 is described. The current detection part 205 detects an effective value of a current flowing on a primary side through a current transformer 206. As illustrated in figure 2A, the current detection part 205 is arranged in the power supply path after branching towards the first heat generating element H1 and the second heat generating element H2 in the parallel connection state of the first heat generating element H1 and second heat generating element H2 (the connection state when the supply voltage of power is 100 V). the current detection part 205 transmits Irms1 which is a square value of the effective current value, which is obtained every period from the commercial power supply frequency, and Irms2 which is a moving average value of Irms1. CPU 203 detects the actual current value per Irms1 every period of the commercial frequency. As an example of the current detection part 205, it is possible to use the method proposed in Japanese open patent application no. 2007-212503. On the other hand, Irms2 is transmitted to relay control part 204. When an excess current flows in current transformer 206 so that Irms2 exceeds a predetermined limit current value (predetermined current), relay control part 204 operates locking parts RL1, RL4 and RL5 in order to keep RL1, RL4 and RL5 in the OFF state. In this way, power supply to the fixture 100 (to be precise, the heater 300) is interrupted. In this case, only the locking parts for RL4 and RL5 can be operated. In this modality, the relays RL1, RL4 and RL5 play a part on the switching part for interrupting the electric power supply for the heat generating elements H1 and H2. In this way, the current sensing part 205 is provided to detect the state in which an excess current is flowing in the power supply path to the heater 300. Like the case where the excess current flows, there is a case where the power supply voltage sensing part 202 or relay RL1 or RL2 when the connection state switching part fails so that the connection state of the first heat generating element H1 and the second heat generating element H2 it is not suitable for the power supply voltage. This case is described later.
    [0051] [0051] In the following, the voltage detection part (second voltage detection part) 207 is described. The voltage sensing part 207 can also be used to detect a failure of the apparatus similarly to the current sensing part 205. The voltage sensing part 207 is arranged to detect one of the voltages that generates both ends of the first element heat generator H1 and generates both ends of the second heat generating element H2 in the state in which the first heat generating element H1 and the second heat generating element H2 are connected in series. The voltage sensing part 207 determines whether the voltage applied to the heat generating element H1 is the 100 V system or the 200 V system. Then, if the voltage is the 200 V system, an RLoff signal is transmitted to the part control relay 204 is set to the LOW state, so as to operate the locking parts RL1, RL4 and RL5. In this way, RL1, RL4 and RL5 are kept in the OFF state so that power supply to the fixture 100 is cut. In addition, the voltage sensing part 207 has an AC3 contact in a position connected directly to the RL2 terminal to detect voltages even if the current transformer 206 or an FU2 fuse fails to disconnect. This is because, for example, if the AC3 contact of the voltage sensing part is disposed between the current transformer 206 and the connector C3, when the current transformer 206 fails to disconnect, both the current sensing part 205 and the voltage detection part 207 is disabled simultaneously.
    [0052] [0052] Below, current fuses FU1 and FU2 are described. These fuses also work as one of the safety measures. As an example of a means to cut a current when excess current flows in the power supply path, current fuses are used. Current fuses FU1 (first current fuse) and FU2 (second current fuse) cut off the power supply to the heat generating element H1 and the heat generating element H2, respectively, when the excess current flows .
    [0053] [0053] Figure 2B shows a circuit diagram illustrating the voltage detection parts 202 and 207. In this embodiment, the power supply voltage detection part 202 and the second voltage detection part 207 have the same structure circuit. The power supply voltage detection circuit 202 detects the voltage between AC1 and AC2, and the second voltage part 207 detects the voltage between AC3 and AC4. Since both have the same circuit structure, the voltage detection portion of the power supply 202 is used to describe the circuit. The action of the circuit to determine whether the fixed voltage applied between AC1 and AC2 is the 100 V system or the 200 V system is described. If the voltage applied between AC1 and AC2 is the 200 V system, the voltage applied between AC1 and AC2 is higher than the zener voltage of a 231 zener diode so that a current flows between AC1 and AC2. The circuit includes a reverse current prevention diode 232, a current limit resistor 234, and a protection resistor 235 for a photocoupler 233. When a current flows in the light emitting diode on the primary side of photocoupler 233, a transistor 235 on the secondary side operates so that a current flows from Vdc through a resistor 236, and a gate voltage from a FET 237 becomes LOW state. When the FET 237 becomes an OFF state, a charge current flows in a capacitor 240 through a resistor 238 Vdc. The circuit includes a reverse current prevention diode 239 and a discharge resistor 241.
    [0054] [0054] When a ratio of a period when the applied voltage between AC1 and AC2 is higher than the zener voltage of the zener diode 231 (Load ON) increases, a ratio of the FET 237 OFF period increases. When the FET 237 OFF period ratio increases, the period when the load current flows through resistor 238 from Vcc increases. Therefore, the voltage of capacitor 240 becomes a high value. When voltage of capacitor 240 becomes higher than a reference voltage of comparator 242 which is a voltage divided by resistor 243 and resistor 244, current flows in an output portion of comparator 242 through resistor 245 of Vcc, with the result that the voltage of the output portion becomes LOW state.
    [0055] [0055] Figures 3A to 3C are schematic diagrams that illustrate the heater 300 which is used in the first modality and connection states of the two heat generating elements corresponding to the power supply voltage.
    [0056] [0056] Figure 3A illustrates heating patterns (heat generating elements), conductive patterns, and electrodes formed on heater substrate 105. Figure 3A also illustrates connection parts for the connectors illustrated in figure 2A to describe connection to the circuit control 200 illustrated in figure 2A. heater 300 includes heat generating elements H1 and H2 formed by resistance heating patterns. The heater 300 also includes a conductive pattern 303. The first H1 heat generating element of the heater 300 is supplied with electrical energy through an electrode E1 (first electrode) and an electrode E2 (second electrode). The second heat generating element H2 is supplied with electricity through electrode E2 and an electrode E3 (third electrode). Electrode E1 is connected to connector C1, electrode E2 is connected to connector C2, and electrode E3 is connected to connector C3.
    [0057] [0057] Next, in the case where the power supply voltages are 100 or 200 V, the relationship between the connection status of H1 and H2 and the energy supplied is explained. Next, each of the energy and current is defined as an energy or current supplied when triac TR1 is triggered due to a 100% load cycle.
    [0058] [0058] Figure 3B is a diagram illustrating the connection state in the case where the power supply voltage is 200 V, that is, the first operational state in which the first heat generating element H1 and the second heating element H2 heat generation are connected in series. Here, for description, it is assumed that the resistance values of the heat generating element H1 and the heat generating element H2 are 20 Ω each. In the first operational state, as the resistors of 20 Ω each are connected in series, the combined resistance value of the heater 300 is 40 Ω. Since the power supply voltage is 200 V, a current of 5 A is supplied to the heater 300 so that the electrical energy is 1,000 W. a current I1 that flows in the first heat generating element and a current I2 that flows in the second element of heat generation is 5 each. A voltage V1 applied to the first heat generating element and a voltage V2 applied to the second heat generating element are 100 V each.
    [0059] [0059] Figure 3C is a diagram illustrating the connection state in the case where the power supply voltage is 100 V, that is, the second operational state in which the first heat generating element H1 and the second heating element H2 heat generation are connected in parallel. In the second operational state, as the resistors of 20 Ω each are connected in parallel, the combined resistance value of the heater 300 is 10 Ω. As the power supply voltage is 100 V, a current of 10 A is supplied to the heater 300 so that the electrical energy is 1,000 W. the current I1 that flows in the first heat generating element and the current I2 that flows in the second element of heat generation are 5 each. The voltage V1 applied to the first heat generating element and the voltage V2 applied to the second heat generating element are 100 V each.
    [0060] [0060] A current, voltage, and electrical energy supplied to the heater is compared between the state of figure 3B and the state of figure 3C. when current Iin is detected, in the state of figure 3B, the current value is 5 A and the electrical energy supplied to the heater is 1,000 W. in the state of figure 3C, the current value is 10 A and the electrical energy supplied to the heater is 1,000 W. thus, when current Iin is detected, electrical energy is the same but current value Iin is different between the first operating state and the second operating state. On the other hand, when current I2 is detected, in the state of figure 3B, the current value is 5A and the electrical energy supplied to the heater is 1,000 W. Also in the state of figure 3C, the current value is 5A and the energy electrical supply to the heater is 1,000 W. so when current I2 is detected, even if the operational state of heater 300 is switched from the first operational state to the second operational state, the current value that is proportional to the electrical energy supplied to the heater heater 300 can be detected.
    [0061] [0061] Furthermore, as the voltage value V2 applied to the heat generating element H2 is the product of the current I2 and the resistance value (20 Ω), instead of the current I2, the voltage V2 applied to the generating element H2 heat can be detected. When the voltage V2 is detected, in the state of figure 3B, the electrical energy supplied to the heater is 1,000 W if the voltage value applied to the heat generating element H2 is 100 V. Also in the state of figure 3C, the electrical energy supplied to the heater is 1,000 W if the voltage value applied to the heat generating element H2 is 100 V. thus, when voltage V2 is detected, even if the operational state of the heater 300 is switched from the first operational state to the second state operational, the voltage value that is proportional to the electrical energy supplied to the heater 300 can be detected.
    [0062] [0062] In addition, in the normal state shown in figures 3B and 3C, even when current I1 is detected, in the state in figure 3B, the current value is 5 A and the electrical energy supplied to the heater is 1,000 W. Also in the state of figure 3C, the current value is 5A and the electrical energy supplied to the heater is 1,000 W. moreover, even when the voltage V1 is detected, in the state of figure 3B, the electrical energy supplied to the heater is 1,000 W if the voltage value supplied to the heater is 1,000 W if the voltage value applied to the heat generating element H1 is 100 V. also in the state of figure 3C, the electrical energy supplied to the heater is 1,000 W if the voltage value applied to the element of H1 heat generation for 100 V.
    [0063] [0063] Thus, regardless of whether the heater is in the first operational state (serial connection state) or the second operational state (parallel connection state), by detecting the current flowing in a heat generating element (I1 or I2) or the voltage applied to a heat generating element (V1 or V2), a current or voltage that is proportional to the electrical energy supplied to the target heat generating element can be detected.
    [0064] [0064] As described above, the current detection part 205 transmits Irms1 which is a square value of the effective current value, which is transmitted over the entire period of the commercial power supply frequency, and Irms2 which is the moving average value of current throughout the commercial frequency period by using Irms1. Even in the state in which the connection status of the relays RL1 and RL2 agrees with the state of the power supply voltage, the 203 CPU uses Irms1 for the control of electric power (triac drive control TR1) so that the electric power supplied to the heater is maintained at 1,000 W or lower.
    [0065] [0065] A case is described where current limit is provided so that the electrical energy supplied to the heater becomes 1,000 W or lower. For example, when current I1 or current I2 is detected, regardless of the operational state of the heater 300 (that is, regardless of whether the heater is in the state of serial connection or state of parallel connection), by providing the current limit at 5 A, the electrical power supplied to the heater can be limited to 1,000 W or lower. In addition, when voltage V1 or voltage V2 is detected, regardless of the operational state of the heater 300 (that is, regardless of whether the heater is in the state of serial connection or state of parallel connection), by providing the voltage limit in 100 V, the electrical power supplied to the heater can be limited to 1,000 W or lower.
    [0066] [0066] As an example of the method of controlling electricity below a predetermined value using the current detection result, the method described in Japanese patent no. 3,919,670 can be adopted. For example, triac TR1 is controlled so that I2 is 5 A or lower in normal control. When an abnormal current is set to 6 A, current I2 is controlled at 5A or lower in normal control. When electrical power control is disabled due to a triac TR1 or similar failure so that an abnormal current of 6 A or higher is detected, CPU 203 sends a signal to relay control part 204 in order to operate relays RL1, RL4 and RL5 to be switched off. Thus, when the current IL or I2, or the voltage V1 or V2 is detected, that is, by projecting the connection position of the current detection part 205 or the voltage detection part 207 as this modality, energy restriction electrical (current restriction) in normal operation can only be performed by adjusting an abnormal current or an abnormal voltage both in the case of the serial connection state and in the case of the parallel connection state.
    [0067] [0067] Figures 4A to 4C illustrate the case where the power supply voltage detection part 202 or the relay RL1 or RL2 when the connection state switching part fails so that the connection state of the first control element heat generation H1 and the second heat generating element H2 does not match the state of the power supply voltage.
    [0068] [0068] Figure 4A is a diagram illustrating a case where the second operational state of the low heater resistance value (ie the parallel connection state) is defined although the power supply voltage is 200 V. in the second operational state, the combined resistance value of heater 300 is 10 Ω. As the power supply voltage is 200 V, a current supplied to the heater 300 is 20 A, and the electrical power is 4,000 V.
    [0069] [0069] Figure 4B is a diagram that illustrates a case where the power supply voltage is 200 V, RL1 is in the ON state, and RL2 is in the OFF state. In this state, a current flows only in the heat generating element H2 (that is, only the heating element H2 generates heat), and the combined resistance value of the heater 300 is 200 Ω. As the power supply voltage is 200 V, the current supplied to the heater 300 is 10 A, and the electrical power is 2,000 W.
    [0070] [0070] Figure 4C is a diagram that illustrates a case where the power supply voltage is 200 V, RL1 is in the OFF state, and RL is in the ON state. In this state, as there is no path to supply current to heater 300, electrical power is not supplied to heater 300.
    [0071] [0071] Among the fault states described above, it is necessary to detect particularly the fault states illustrated in figures 4A and 4B in which greater electrical energy is supplied to the heater 300 than in the normal state. In these fault states, as the electrical power supplied to the heater becomes too high, the safety circuit using a temperature sensing element such as thermistor 111, thermal fuse FU1 or FU2, or thermocouple 112 may be insufficient in the response speed to interrupt the electric power supply to the heater. If the interruption of the electrical power is delayed, the heater can be broken by the thermal voltage in the case of the fixture that uses a ceramic heater.
    [0072] [0072] A current, voltage and electrical energy supplied to the heater is compared between the failure states illustrated in figures 4A and 4B. when current Iin is detected, in figure 4B, the current value of current Iin is 10 A and the electrical energy supplied to the heater 300 is 2,000 W. as the current value is equal to current Iin in the normal state illustrated in figure 3C , the fault state may not be detected only by the current detection result of current Iin.
    [0073] [0073] When current I1 is detected, in figure 4B, the current value of current I1 is 0 A and the electrical energy supplied to the heater 300 is 2,000 W. in the state in which electrical energy is supplied to the heater 300, such as current I1 does not flow, the fault state may not be detected only by the current detection result of current I1 as illustrated in figure 4B. when current I2 is detected, the current value of 10 A which is twice as large as the current value in the normal state described above with reference to figures 3A to 3C can be detected regardless of the fault state of relay RL1 or the relay RL2. Therefore, the fault state shown in figure 4A or 4B can be detected. When voltage V2 is detected, the voltage value of 200 V (overvoltage) which is twice as large as the voltage value in the normal state described above with reference to figures 3A to 3C can be detected regardless of the fault state of relay RL1 or RL2 relay. Therefore, the fault states illustrated in figures 4A and 4B can be detected. Thus, each of the fault states illustrated in figures 4A and 4B can be detected by detecting current I2 flowing in the second heat generating element H2 between electrode E2 and electrode E3, or by detecting the voltage V2 applied to the second element H2 heat generation. Note that the heat generating element H2 to be detected by the current sensing part 205 or the voltage sensing part 207 is the heat generating element that is connected to the commercial power supply 201 without relay RL2 having the contact transfer.
    [0074] [0074] As described above, the current sensing part 205 is arranged in the energy supply path after branching towards the first heat generating element H1 and the second heat generating element H2 in the parallel connection state. In particular, in the structure in which connection of the two heat generating elements is switched between the serial connection state and the parallel connection state by combining the relay RL1 having the closing contact or the opening contact and the relay RL2 having the transfer contact, it is preferred to arrange the current detection part 205 in the energy supply path of the heat generating element H2 which is connected to the commercial power supply 201 without relay RL2 having the transfer contact.
    [0075] [0075] In addition, the second voltage sensing part 207 is arranged to detect one of the voltages that generates both ends of the first heat generating element H1 and generates both ends of the second heat generating element H2 in the serial connection status. In particular, in the structure in which connection of the two heat generating elements is switched between the serial connection state and the parallel connection state by combining the relay RL1 having the closing contact or the opening contact and the relay RL2 having the transfer contact, it is preferred to arrange the voltage sensing part 207 in order to detect the voltage that generates both ends of the heat generating element H2 that is connected to the commercial power supply 201 without relay RL2 having the contact of transfer.
    [0076] [0076] In addition, the current fuse FU1 is used in the current path flowing in the first heat generating element H1, and the current fuse FU2 is used in the current path flowing in the second heat generating element H2. Thus, the current fuse FU1 and the current fuse FU2 operate in the fault state illustrated in figure 4A, while the current fuse FU1 operates in the fault state illustrated in figure 4B. when the current fuse FU1 is used in the current path flowing in the first heat generating element H1 and the current fuse FU2 is used in the current path flowing in the second heat generating element H2, it is possible to provide a excess current cut-off corresponding to the fault states illustrated in figures 4A and 4B, respectively.
    [0077] [0077] Figures 5A and 5B are flowcharts illustrating a control sequence of the clamping device 100 by CPU 203 and the relay control part 204 of the first embodiment of the present invention.
    [0078] [0078] In S500, when the control circuit 200 becomes the reserve state, the control starts and the process flow continues to S501. In S501, relay control part 204 turns on RL4. In S502, the voltage range of the power supply is determined based on the VOLT signal which is an output of the voltage sensing part. If the power supply voltage is the 100 V system, the process flow continues to S504. If the power supply voltage is the 200 V system, the process flow proceeds to S503. In S503, the relay lock part RL1 of relay control part 204 operates so that relay RL1 is kept in the OFF state, and the process flow proceeds to S505. At S504, CPU 203 transmits signal RL1on and signal RL2on from state HIGH to relay control part 204, and from there relay control part 204 connects RL1 and RL2, and the process flow proceeds to S505. Until the start of print control is determined at S505, the process from S502 to S504 is performed repeatedly. When print control is started, the process flow proceeds to S506.
    [0079] [0079] In S506, CPU 203 transmits the RL5 on signal of HIGH status to relay control part 204, and from there relay control part 204 turns on RL5.
    [0080] [0080] In S507, if the voltage detection part 207 detects a voltage higher than a predetermined voltage, that is, it detects overvoltage, the RLoff signal is in the LOW state, and the process flow proceeds to S509.
    [0081] [0081] In S508, if the voltage based on the Irms2 output of the current detection part 205 becomes a predetermined or higher threshold voltage value, the process flow proceeds to S509.
    [0082] [0082] In S509, relay control part 204 operates locking parts RL1, RL4, and RL5 so that RL1, RL4 and RL5 are kept in the OFF state (cut-off state), and the process flow proceeds to S510. In S510, an abnormal state is notified so that the printing operation is put on an emergency stop, and the process flow proceeds to S513 to end control. If the abnormal state is not detected at S507 and S508, the process flow continues to S511. In S511, CPU 203 controls the triac TR1 using PI control based on the TH signal transmitted from the temperature sensing element 111 and the Irmsl signal transmitted from the current sensing part, in order to control the electrical energy to be supplied to the heater 300 (as phase control or wave number control). Until the end of printing is determined at S512, the process from S507 to S511 is repeated. When printing is finished, the process flow proceeds to S513 to end control.
    [0083] [0083] Thus, in the image forming apparatus having the structure in which the connection of two heat generating elements is switched between the serial connection state and the parallel connection state, at least one of the current detection part 205 and voltage sensing part 207 is provided and its arrangement position is designed as this mode. In this way, a device failure can be detected, and consequently the device's reliability can be improved. Second modality
    [0084] [0084] The description of the same structure as in the first modality is omitted.
    [0085] [0085] Figure 6 illustrates a control circuit 600 of heater 300 of a second mode. In figure 6, only the structure of the switching part of the connection state (relay) is different from that in the first mode. The arrangement of the current detection part 205 and the voltage detection part 207 is the same as that in the first embodiment, and consequently the description of the arrangement of the same is omitted.
    [0086] [0086] The voltage detection part and the relay control part are described below. Figure 6 illustrates RL1, RL2, RL3, RL4 and RL5 indicating connection states of the contacts in the OFF state of power supply. Note that RL1 is assumed to have a close contact or an open contact. In addition, it is assumed that RL2 has a close contact. In addition, it is assumed that RL3 has an open contact. When the voltage sensing part 202 detects 200 V, a relay control part 604 operates the lock part RL1 so that relay RL1 is turned off. A CPU 603 turns off RL2 (to be non-conductive state) according to the result of voltage detection, and then off on RL3 (to be conductive state). RL3 has an aspect that RL3 operates together with RL2, and RL2 is controlled not to become the conductive state simultaneously with RL3 (not to become the state in which RL2 is ON while RL is OFF) with a time difference. The combination of RL2 and RL3 has the same action as RL2 in the first modality. In addition, when RL5 is on, the fixture 100 can be supplied with electrical power. In this state, as the first heat generating element H1 and the second heat generating element H2 are connected in series, the heater 300 has a high resistance value. If the voltage detection part 202 detects 100 V, CPU 603 transmits the signal RL1on of state HIGH so that relay control part 604 turns on RL1. CPU 603 transmits an RL3 on signal of HIGH status according to the voltage detection result so that RL3 is turned on (to be conductive state). In addition, when RL5 is switched on, the fixture 100 can be supplied with electrical power. In this state, as the first heat generating element H1 and the second heat generating element H2 are connected in parallel, the heater 300 has a low resistance value.
    [0087] [0087] Thus, also in the structure of the switching part of the connection state such as control circuit 600, a device failure can be detected so that the reliability of the device can be improved, by supplying at least one of the part of current detection 205 and voltage detection part 207 and for projecting its arrangement position as in this modality. Third modality
    [0088] [0088] The description of the same structure as in the first modality is omitted.
    [0089] [0089] Figure 7 illustrates a control circuit 700 of a heater 800 of a third modality. In figure 7, only the structure of the switching part of the connection state (relay) and the increased number of heater electrodes are different from those in the first mode. The arrangement of the current detection part 205 and the voltage detection part 207 is the same as in the first embodiment.
    [0090] [0090] The voltage detection part and the relay control part are described below. Figure 7 illustrates RL1, RL2, RL4 and RL5 indicating connection states of the contacts in the OFF state of power supply. When the voltage detection part 202 detects 200 V, a relay control part 704 operates the lock part RL1 so that RL1 is kept in the OFF state. RL2 has an aspect to operate together with RL1, and RL2 becomes the OFF state simultaneously with RL1. In addition, when RL5 is switched on, the fixture 100 can be supplied with electrical power. In this state, as the first heat generating element H1 and the second heat generating element H2 are connected in series, the heater 800 has a high resistance value. If voltage detection part 202 detects 100 V, relay control part 704 switches on RL1. RL2 has an aspect to operate together with RL1, and RL2 becomes the ON state simultaneously with RL1. In addition, when RL5 is switched on, the fixture 100 can be supplied with electrical power. In this state, as the first heat generating element H1 and the second heat generating element H2 are connected in parallel, the heater 800 has a low resistance value.
    [0091] [0091] Figures 8A to 8C are schematic diagrams illustrating the heater 800 used for the third modality, and heating elements of the heater 800.
    [0092] [0092] Figure 8A illustrates heating patterns, conductive patterns, and electrodes formed on the substrate. In addition, to illustrate connection to the control circuit 700 illustrated in figure 7, the schematic diagram of figure 7 is illustrated.
    [0093] [0093] The heater 800 includes the elements of heat generation H1 and H2 formed by resistance heating patterns. The heater 800 also includes a conductive standard 803. The first heat generating element H1 of the heater 800 is supplied with electricity through electrodes E1 and E2, and the second heating element H2 is supplied with electricity through the electrodes E3 and E4. Electrode E1 is connected to connector C1, electrode E2 is connected to connector C2, electrode E3 is connected to connector C3, and electrode E4 (fourth electrode) is connected to connector C4.
    [0094] [0094] Figure 8B is a diagram illustrating the first operational state in which the first heat generating element and the second heat generating element are connected in series when the power supply voltage is 200 V.
    [0095] [0095] Here, for description, it is assumed that the resistance values of the heat generating element H1 and heat generating element H2 are 20 Ω each. In the first operational state, as the resistors of 20 Ω each are connected in series, the combined resistance value of the heater 800 is 40 Ω. Since the power supply voltage is 200 V, a total current Iin of 5 A is supplied to the heater 800 so that the electrical energy supplied to the heater is 1,000 W. the current I1 flowing in the first heat generating element and the current I2 flowing in the second heat generating element are 5 each. The voltage V1 of the first heat element and the voltage V2 of the second heat element are 100 V each.
    [0096] [0096] Figure 8C is a diagram illustrating the second operational state in which the first heat generating element and the second heat generating element are connected in parallel when the power supply voltage is 100 V. in the second state operational, as the resistors of 20 Ω each are connected in parallel, the combined resistance value of the heater 800 is 10 Ω. Since the power supply voltage is 100 V, the total current Iin of 10 A is supplied to the heater 800 so that the electrical energy supplied to the heater is 1,000 W. the current I1 flowing in the first heat generating element H1 and the current I2 flowing in the second heat generating element H2 is 5 each. The voltage V1 of the first heat element and the voltage V2 of the second heat element are 100 V each.
    [0097] [0097] Figure 8D is a diagram illustrating a case where the second operational state of the low heater resistance value, in which the first heat generating element and the second heat generating element are connected in parallel, is defined due to a failure of the voltage detection part 202 or the relay control part 704 although the power supply voltage is 200 V. in the control circuit 700, for example, as RL1 and RL2 operate together even if the control circuit drive or the voltage sensing part 202 on the secondary side of RL1 and RL2 fails, a fault state of the control circuit 700 can be limited to the state illustrated in figure 8D. in the second operational state, as the 20 Ω resistors are connected in parallel, the combined resistance value of the heater 800 is 10 Ω. As the power supply voltage is 200 V, the total current Iin of the heater 800 is 20 A, and the electrical power is 4,000 W. the current I1 of the first heat generating element H1 and the current I2 of the second generating element of H2 heat are 10 each. The voltage V1 of the first heat generating element and the voltage V2 of the second heat generating element are 200 V each.
    [0098] [0098] A current, voltage, and electrical energy supplied to the heater is compared between the state of figure 8B and the state of figure 8C. when the current Iin is detected, in the state of figure 8B, the current Iin is 5 A and the electrical energy supplied to the heater is 1,000 W. in the state of figure 8C, the current Iin is 10 A and the electrical energy supplied to the heater is 1,000 W. Thus, when current Iin is detected, electrical energy is the same, but current value Iin is different between the first operating state and the second operating state. On the other hand, when current I1 is detected, in the state of figure 8B, the current value of I1 is 5 A and the electrical energy supplied to the heater is 1,000 W. Also in the state of figure 8C, the current value of I1 is 5 A and the electrical power supplied to the heater is 1,000 W. I2 is equal to I1. In addition, when voltage V1 is detected, voltage V1 is 100 V and the electrical energy supplied to the heater is 1,000 W in the state of figure 8B. also in the state of figure 8C, the voltage V1 is 100 V and the electrical energy supplied to the heater is 1,000 W. V2 is equal to V1. Thus, when current I1 or I2, or voltage V1 or V2 is detected, even if the operational state of the heater 800 is switched from the first operational state to the second operational state, the current value or the voltage value that is proportional to the electrical energy supplied to the heater 800 can be detected.
    [0099] [0099] Thus, even with the structure of the switching part of the connection state as this mode, a device failure can be detected by projecting the arrangement position of the current detection part 205 and the voltage detection part 207 .
    [0100] [0100] The three modalities described above are based on the image formation apparatus including the fixation part that uses the endless belt. However, the present invention can also be applied to an image forming apparatus including a fastening part having another structure without the endless belt as long as the connection of the two heat generating elements is switched between the serial connection state and the parallel connection state in the structure of the fastening part.
    [0101] [0101] In addition, the above description is based on the image forming apparatus having the structure in which connection of the two heat generating elements is automatically switched between the serial connection state and the parallel connection state according to the voltage detected from the power supply voltage detection part. However, the present invention can also be applied to an image forming apparatus having a structure in which connection of the two heat generating elements is switched manually between the serial connection state and the parallel connection state.
    [0102] [0102] In addition, the above description is based on the apparatus including both the current detection part 205 and the voltage detection part 207, but it is sufficient to have one of the current detection part 205 and the current detection part voltage 207.
    [0103] [0103] In addition, the above description is based on the structure in which the current sensing part 205 is arranged in one of the power supply paths after branching towards the first heat generating element H1 and the second heat generating element H2 heat in the parallel connection state, but the current detection part 205 can be arranged in each of the energy supply paths after branching.
    [0104] [0104] In addition, the above description is based on the structure in which only a voltage sensing part 207 is arranged to detect one of the voltages that generates the two ends of the first heat generating element H1 and generates both ends of the second heat generating element H2 in the state of serial connection, but the voltage sensing part 207 can be arranged for each of the heat generating elements.
    [0105] [0105] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the exemplary embodiments disclosed. The scope of the following claims should be agreed upon the broadest interpretation to cover all such modifications and equivalent structures and functions.
    [0106] [0106] This application claims the benefit of Japanese patent application no. 2010062464, filed on March 18, 2010, and Japanese patent application no. 2011 -024986, filed on February 8, 2011, which are hereby incorporated by reference here in full.
    权利要求:
    Claims (11)
    [0001]
    Image forming apparatus comprising: a fixing part (100) including a first heat generating element (H1) and a second heat generating element (H2) respectively adapted to generate heat by electrical energy supplied from a commercial energy source (201) via a energy supply path to heat fix an image formed on a recording material (P) on the recording material (P); and a connection state switching part (RL1, RL2) adapted to switch connection of the first heat generating element (H1) and second heat generating element (H2) between a serial connection state and a parallel connection state; characterized by a current sensing part (205) adapted to detect a current flowing in the power supply path, wherein the current sensing part is arranged in the energy supply path after branching towards the first heat generating element (H1) and the second heat generating element (H2) in the parallel connection state.
    [0002]
    Imaging apparatus according to claim 1, characterized by the fact that it additionally comprises: a power supply voltage sensing part (202) adapted to detect a commercial power supply voltage (201); and a control part (204) adapted to control the connection state switching part (RL1, RL2) according to the voltage detected by the power supply voltage sensing part (202).
    [0003]
    Imaging apparatus according to claim 1, characterized by the fact that: the connection state switching part (RL1, RL2) includes a relay (RL1) having one of a closing contact and an opening contact, and a relay (RL2) having a transfer contact; and the current detection part (205) is arranged in the power supply path for one of the first heat generating element (H1) and the second heat generating element (H2) which is connected to the commercial power supply (201 ) without the relay (RL2) having the transfer contact.
    [0004]
    Image forming apparatus according to claim 1, characterized in that it also comprises a second voltage sensing part (207) adapted to detect a voltage, in which the second voltage sensing part (207) is arranged in order to detect one of a voltage generated at both ends of the first heat generating element (H1) and a voltage generated at both ends of the second heat generating element (H2) in the state of serial connection.
    [0005]
    Image forming apparatus according to claim 1, characterized in that it additionally comprises a switching part (RL1, RL4, RL5) arranged in the energy supply path, where, when the current detected by the current sensing part (205) exceeds a predetermined current, the switching part (RL1, RL4, RL5) is activated so that the supply of electricity to the first heat generating element (H1) and the second heat generating element (H2) is interrupted.
    [0006]
    Imaging apparatus according to claim 1, characterized by the fact that the fixing part (100) includes: an endless belt (102); a heater (300) including the first heat generating element (H1) and the second heat generating element (H2), which is placed in contact with an internal surface of the endless belt (102); and a nip part forming element (108) adapted to form a nip part to subject the recording material (P) to fixation processing, together with the heater (300) through the endless belt (102).
    [0007]
    Image forming apparatus comprising: a fixing part (100) including a first heat generating element (H1) and a second heat generating element (H2) respectively adapted to generate heat by electrical energy supplied from a commercial energy source (201) via a energy supply path to heat fix an image formed on a recording material (P) on the recording material (P); and a connection state switching part (RL1, RL2) adapted to switch connection of the first heat generating element (H1) and second heat generating element (H2) between a serial connection state and a parallel connection state; characterized by a voltage sensing part (207) adapted to detect a voltage, wherein the voltage sensing part (207) is arranged to detect one of a voltage generated at both ends of the first heat generating element (H1 ) and a voltage generated at both ends of the second heat generating element (H2) in the state of serial connection.
    [0008]
    Imaging apparatus according to claim 7, characterized by the fact that it additionally comprises: a power supply voltage sensing part (202) adapted to detect a voltage from the commercial power source (201); and a control part (204) adapted to control the connection state switching part (RL1, RL2) according to the voltage detected by the power supply voltage sensing part (202).
    [0009]
    Imaging apparatus according to claim 7, characterized by the fact that: the connection state switching part (RL1, RL2) includes a relay (RL1) having one of a closing contact and an opening contact, and a relay (RL2) having a transfer contact; and the voltage sensing part (207) is arranged to detect one of the voltage generated at both ends of the first heat generating element (H1) and the voltage generated at both ends of the second heat generating element ( H2) which is connected to the commercial power source (201) without the relay (RL2) having the transfer contact.
    [0010]
    Image forming apparatus according to claim 7, characterized in that it additionally comprises a switching part (RL1, RL4, RL5) arranged in the energy supply path, where, when the voltage detected by the voltage sensing part (207) exceeds a predetermined voltage, the switching part (RL1, RL4, RL5) is activated so that the electrical supply to the first heat generating element (H1) and the second heat generating element (H2) is interrupted.
    [0011]
    Imaging apparatus according to claim 7, characterized by the fact that the fixation part includes: an endless belt (102); a heater (300) including the first heat generating element (H1) and the second heat generating element (H2), which is placed in contact with an internal surface of the endless belt (102); and a nip part forming element (108) adapted to form a nip part to subject the recording material (P) to fixation processing, together with the heater (300) through the endless belt (102).
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    法律状态:
    2019-01-08| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-10-29| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-08-11| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application [chapter 6.1 patent gazette]|
    2020-11-24| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-01-12| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 16/03/2011, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2010-062464|2010-03-18|
    JP2010062464|2010-03-18|
    JP2011024986A|JP4818472B2|2010-03-18|2011-02-08|Image forming apparatus|
    JP2011-024986|2011-02-08|
    PCT/JP2011/057072|WO2011115301A1|2010-03-18|2011-03-16|Image forming apparatus|
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