• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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  • 优先权
    • 专利摘要:
    printing system, method for liquid electro-photographic printing and method for preparing liquid electro-photographic ink a printing system (200) using high solids content inks (205) includes a mixing unit (210) for receiving an ink with high solids content (205) and produce a concentrate ink, and an intermediate tank (220) to receive the concentrate ink from the intermediate tank (22) and produce the printing ink. a liquid electro-photographic printing motor (225) receives printing ink from the ink tank (160). An ink return line (240, 242, 244) is connected between the mixing unit (210) and at least one of the buffer tank (220) and the ink tank (160), the mixing unit (210) receives fluid from at least one of the buffer tank (220) and the ink tank (160), and mixes the fluid with a paint with high solids content (205). a method for liquid electro-photographic printing using a high solids content ink is also provided.
    公开号:BR112013019351B1
    申请号:R112013019351-4
    申请日:2011-01-31
    公开日:2021-06-29
    发明作者:Mark Sandler；Shai Lior；Avner Schneider
    申请人:Hewlett-Packard Delopment Company, L.P.；
    IPC主号:
    专利说明:

    Invention History
    An electro-photographic (EP) printing device forms an image on a media, typically first by selectively loading a photo-conductive drum in correspondence with the image. A dye is applied to the photoconductive drum where the drum was loaded, and then this dye is transferred to form the image onto a media. Liquid Electro-Photographic (LEP) printing devices employ an electro-photographic liquid ink, containing a carrier fluid, and solid pigments suspended in the carrier. During printing, the carrier fluid allows the solid particles to be mixed, transported, and deposited on the photoconductive cylinder. Liquid ink is applied to the photoconductive drum where the drum was loaded. Before solid particles are deposited on the substrate, most of the carrier fluid is extracted. A large percentage of the carrier fluid is captured and recycled. However, during the printing process, an excessive amount of carrier accumulates in the printing system, and is discarded. Brief Description of Drawings
    The accompanying drawings illustrate various configurations of the principles described herein, and form an integral part of the specification. The illustrated configurations are merely exemplary and do not limit the scope of the claims. Figure 1 is a diagram of an illustrative digital LEP system in accordance with an example of the principles described herein; Figure 2 is a diagram of an illustrative digital printing system using electro-photographic inks with high solids content in accordance with an example of the principles described herein; Figure 3A is an illustrative graph showing amounts of carrier excess produced for paints with different solids contents in accordance with an example of the principles described herein; Figures 3B and 3C are diagrams of illustrative printed substrates in accordance with an example of the principles described herein; Figure 4 is an illustrative digital printing system diagram using electro-photographic inks with high solids content in accordance with an example of the principles described herein; Figure 5 is a flowchart showing an illustrative method for producing high solids content electro-photographic liquid inks for use in the printing system in accordance with an example of the principles described herein; Fig. 6 is a flowchart showing a method for producing electro-photographic liquid inks with high solids content for use in a printing system in accordance with an example of the principles described herein; Figure 7 is a flowchart showing an illustrative method for using electro-photographic liquid inks having a high solids content in a printing system in accordance with an example of the principles described therein; and Figure 8 is a flowchart showing an illustrative method for using electro-photographic inks with high solids content in a printing system in accordance with an example of the principles described therein. Throughout the drawings, identical reference numbers are used to designate similar, but not necessarily identical, elements. Detailed Description of the Invention
    As discussed herein, liquid electro-photographic (LEP) printing devices employ a liquid ink that is applied to a photoconductive cylinder that adheres to the charged portions of the cylinder. Liquid ink contains a carrier fluid and solid pigments that are suspended in the carrier. The LEP printing device uses liquid ink to form images having an offset look and feel and provides photographic quality reproduction.
    Ink, including carrier and solid particles, is produced and transferred to the printing site. During printing, the carrier fluid allows the solid particles to be mixed, transported, and deposited on the photoconductive cylinder. Additionally, ink particles absorb a small percentage of the carrier. This alters the mechanical behavior of the ink particles, and makes the ink particles more plastic, forming a uniform film on the cylinder. Before solid particles are deposited on the substrate, most of the carrier fluid is extracted. A large percentage of the carrier fluid is captured and recycled. However, during printing, an excessive amount of carrier accumulates in the printing system, and is discarded. Purchasing, storing, and disposing of an excess amount from the carrier represents a significant cost.
    In the following description, for purposes of explanation, numerous specific details will be described to provide a more complete understanding of the present systems and methods. As should be apparent to those skilled in the art, however, the present apparatus, systems, and methods can be practiced and used without such specific details. When referring to the term "a configuration" "an example" or the like, it should be understood that a particular aspect, structure, or feature described in connection with a configuration or examples that may be included in at least one configuration does not necessarily appear in other settings. The various modalities of the term “in a configuration” or similar, which may appear in various places throughout the specification, do not necessarily refer to the same configuration.
    As used in the specification and accompanying claims, the term “Liquid Electro-Photographic Printer (LEP)” (“printing press”) refers to a printing process that combines the creation of an electrostatic image with a cover image transferred to a substrate . As used in this specification and the appended claims, the term "high solids content paint" refers to paints having a solids content of 40% or more. In one example, paint with high solids content is at least 65% solids. These solids are typically agglomerates with aggregate particle size of hundreds of microns. These particles are adapted to absorb a portion of the liquid carrier. For example, an amount corresponding to 5% of the liquid carrier can be absorbed by the particles. Figure 1 is a diagram of an illustrative configuration of a digital LEP system 100 that uses a high solids content ink. A number of illustrative modifications to the LEP system, then, are described for using a high solids content ink. In an LEP system, the desired image is initially formed on the photo-imaging cylinder 105, transferred to a cover cylinder 120, and then transferred to the substrate 140. The desired image is communicated to the printing system 100 in form. digital. The desired image can be text, pictures, black and white, partially colored, full color, or any combination of text and images.
    According to an illustrative embodiment, an image is formed on the photo-imaging drum 105 in the photo charging unit 110. A uniform static charge is deposited on the photo-imaging drum 105 by corona wire. As the photo imaging cylinder 105 rotates, it passes through the laser imaging portion of the photo charging unit 110. A number of diode lasers dissipate static charges in portions of the imaging area to make an invisible electrostatic charge pattern. , which reproduces the image to be printed.
    A number of ink tanks 160 containing inks is supplied to the corresponding “Binary Ink Developers” 115 units. There is an ink tank 160 with the corresponding BID 115 unit for each ink color. For illustration purposes, only a 160 tank is shown. In one illustrative embodiment, paint is supplied in concentrated form in a 155 paint can. The concentrated slurry typically includes about 15% to about 25% paint solids, with balance carrier fluid. The concentrated slurry is dispensed from paint can 155 to paint tank 160. In paint tank 160, the concentrated slurry is mixed with a carrier fluid to form a paint with about 1% to 10% paint solids, with balance carrier fluid. Carrier fluid is added to ink tank 160 from carrier tank 156 via carrier feed line 156. The ink characteristics in ink tank 160 are carefully controlled to maintain the print quality of system 100. For example, ink tank 160 may contain a number of sensors that detect the temperature, density, charge, quantity, and flow rate of ink. If any of these parameters are outside the intended range, an appropriate correction must be made. For example, if the ink temperature is too high, a coolant can circulate through a heat exchanger in the ink tank to cool the ink. If the paint density is too low, an additional amount of paint solids must be added from paint can 155. A pump in paint tank 160 provides BID 115 associated with the desired amount of paint through the BID 150 feed line.
    During printing, a suitable BID unit 115 is engaged to the photo-imaging cylinder 105. The engaged BID unit 115 features an ink application roller including a uniform film of ink to the imaging cylinder 105. The ink contains particles of electrically charged pigment (ink solids that are attracted to opposing electric fields in the imaging areas of the photo-imaging drum 105. Ink solids are repelled from the non-imaging areas. Carrier fluid and unused ink solids return via BID 152 return line to ink tank 160 for reconditioning and recirculation to BID 115 unit.** When the image areas of a print cover a large area, the amount of ink solids extracted from the ink increases. ink solids produces an additional excess of carrier fluid. For example, printing a very large photograph requires more ink solids than printing a photograph. and one page of text, and therefore produces a greater amount of excess carrier fluid.
    The photo-imaging drum 105 now has an ink image of one color (single color) formed by the ink solids adhering to opposite charged portions of the photo-imaging drum 105. In addition to the ink solids, the photo-imaging drum. 105 imaging also contains some carrier fluid. The image cylinder 105 continues to rotate and transfer ink images to a cover cylinder 120, ie the process of transferring the ink image from its origin on the photo image cylinder 105 to a cover cylinder 120. The cover cylinder 120 then transfers the ink image to the substrate, ie the process called “offset printing”. The offset printing method provides several advantages. First, the offset process protects the photo-imaging cylinder 105 from wear, which would occur if the substrate were to directly contact it. Second, the coating cylinder 120 is covered with a renewable rubber coating, which compensates for any unevenness of the substrate surface, and deposits the ink evenly in any depressions or grains. Thus, the illustrative digital LEP system 100 can provide an impression over a wide range of substrate surfaces, textures, and thicknesses.
    Cover roller 120 is heated to increase plasticity and density of ink solids. The heat vaporizes most of the carrier fluid that has been transferred from the imaging cylinder 105 to the cap cylinder 120. Most of the vapor is captured by a condensing station 175. The condensing station 175 is only a part of the capture and control system for excess carrier fluid. A variety of other components including covers, fans, trays, separators, particulate filters, and other elements can be used to capture and recycle the carrier fluid.
    Substrate 140 enters printing system 100 from the right side over feed tray 125, from there to printing cylinder 130. When substrate 140 contacts cover cylinder 120, an ink image of one color is transferred to the substrate 140.
    The photoimaging cylinder 105 continues to rotate, and moves the portion of the cylinder surface that previously contained the ink image to a cleaning station 135. The cleaning station 135 serves multiple purposes, including removing particulates from the tray, or fluid from the imaging cylinder 105 and cool the outer surface of the imaging cylinder 105. The cleaning station 135 can use recycled carrier fluid as a cleaning agent. Excess carrier fluid or contaminated carrier fluid from cleaning station 135 may join the carrier fluid from condensing station 175, and be transferred via capture line 154 to carrier tank 165. It can be refurbished using a number of techniques. For example, water can be extracted from the carrier fluid using a separator, and particulates can be extracted from the carrier fluid using a porous or electrostatic filter. When carrier fluid accumulates, carrier tank 165 stores the carrier fluid, which is then transferred to a waste tank 170.
    The creation, transfer, and cleaning of the imaging drum 105 is an ongoing process with hundreds of images being created and transferred per minute. To form a one color image (such as a black and white image) a passage of substrate 140 between print roller 130 and cover roller 120 completes the image transfer. To provide a multicolored image, substrate 140 is retained on print roller 130, and makes multiple contacts with cover roller 120. In each pass, an additional color is added to the substrate. For example, to generate a four-color image, the photo loading unit 110 forms a second pattern on the photo-imaging drum 105, which receives the second color of ink from the second binary ink developer 115. As described above , this second ink pattern is transferred to cover cylinder 120, and prints onto substrate 140 as it rotates with print cylinder 130. This continues until the desired image is formed on substrate 140. Following complete formation of the desired image on substrate 140, substrate 140 can either exit the machine or be duplexed to form a second image on the opposite surface of substrate 140.
    There can be a number of ink tanks 160 and associated BIDs 115. For clarity, only one tank is shown in the specification. Typically, there is an ink tank to hold one of the seven 115 BIDs to ground contact. In an offset printing technique four process colors are used - Cyan, Magenta, Yellow, Black. Some more advanced processes use six process colors to compensate for limitations of the four-color method. Additionally, spot colors may be desirable to provide a desired visual or textual effect. For example, spot colors can produce metallic effects, fluorescents, direct varnishes, coatings, and other effects. Spot colors can be mixed on site or by request. Custom spot colors can be more efficient in generating the desired color and/or providing specific visual effects on the printed substrate. For example, spot colors are particularly effective for security printing, such as for printing money, passports, bonds, and other printed documents.
    The advantages of the illustrative digital LEP offset system described above include dot gain, optical densities and consistent colors. As the printing system is digital, the operator can change the image being printed at any time, and without having to reconfigure. Furthermore, the printing system produces uniform image brightness, a wide range of ink colors, compatibility with a wide variety of substrate types, and instant image drying.
    The physical input to be introduced into the printing system is the ink concentrate (ink solids and carrier fluid) and substrate material. During the printing process, a very small amount (about 5% to 15%) of carrier fluid is consumed or lost. Most of the carrier fluid is recovered. Thus, the physical output of the printing system is a printed image (ink solids on the substrate) and excess carrier fluid. Although printed images are the desired result, excess carrier fluid is a residual that requires proper disposal. By minimizing the amount of carrier fluid introduced into the system, the cost of transporting, storing, and disposing of the carrier fluid is reduced. Furthermore, the overall cost of producing printed substrates can be reduced. Figure 2 is a diagram of a digital printing system 200 using electro-photographic inks with a high solids content. This figure focuses on the formation process and the path of carrier fluid in the system. The print engine described with reference to Figure 1 is shown as box 225. In this implementation, a high solids content ink 205 is introduced into system 200. The high solids content ink 205 has a much higher solids content than the paint slurry discussed with respect to Figure 1. For example, the high solids content paint 205 can include about 50% to 95% paint solids, with balance carrier fluid. The high solids ink 205 is in the form of agglomerated particles large enough to not create a dust streak. These agglomerated particles are supplied to a dosing and mixing unit 210, where they are combined with fluid from the carrier tank, intermediate tank 220, and ink tank 160. A high shear mixer 215 combines ink having a high content of solids with the fluid and breaks the agglomerated particles into smaller particles. The high shear mixer 215 can be an impeller, gear pump, ultrasonic unit, or other mixers, which achieve shear levels that break up the agglomerated particles and disperse them to form a concentrated paint with solids content of approximately 10% to 30%.
    This concentrated ink is then transferred to an intermediate tank 220, where the concentrated ink can be stored and further conditioned. Intermediate tank 220 can accept additional carrier fluid via a system of lines 240, 242, 244 and attached valve 230, 235. As dictated by print demand, concentrated ink from intermediate tank 220 is selectively added, via the valve 232, to ink tank 160, where the concentrated ink is then diluted with carrier fluid to form a printing ink with about 1% to 10% solids.
    Printing ink is supplied from ink tank 160 to print engine 225. As discussed above, in electro-photographic print engine 225, BID applies an ink film to the charged portions of the imaging cylinder. The paint film consists of about 20% to 25% paint solids. The ink film is then deposited onto the heated cover roller, where the carrier fluid is separated and condensed. This increases the solids content to about 95% with the remaining portion of carrier fluid being absorbed into the particles.
    Excess carrier fluid is collected by capture and control devices 230, reconditioned and returned to carrier tank 165 for recycling. A capture and control efficiency of 85% to 90% has been found to provide sufficient carrier fluid return to the system to allow the use of high solids content inks without having to add separate carrier fluid to a printer. In addition, high capture and control efficiency reduces the amount of aerial volatile organic compounds that can contaminate surfaces. Various other systems in printing system 200 can extract carrier fluid contained in carrier tank 165, as needed, to create the desired ink, or perform a desired cleaning function. Multiple valves 230, 235 control the flow of paint and carrier fluid between the various tanks 160, 165, 210, 220.
    If there is excess carrier fluid generated by the system, the excess fluid is transferred from carrier tank 165 to overflow tank 170 for disposal. However, by introducing a high solids content ink 205 into the system, the amount of carrier fluid consumed or lost during the printing process (ie the carrier fluid outflow) can be roughly compensated for by the amount of carrier fluid introduced into the process. Printing. Because less amount of carrier fluid is introduced into the system, zero or very little amount of carrier fluid will be generated in the printing process.
    The intermediate tank 220 accepts fluid from the ink tank 160, and distributes fluid to both the mixing unit 210 and the ink tank 160. The fluid coming from the intermediate tank 220 is directed to the desired location through a system of lines 240, 242, 244 and valves 230, 232, 235 coupled. The intermediate tank 220 also serves a number of functions. For example, buffer tank 220 may allow a batch process in mixing unit 210. Mixing unit 210 may receive a specified amount of paint solids 205 and a corresponding amount of carrier fluid from intermediate tank 220 , ink tank 160, and/or carrier tank 165. The charge is then mixed to break the ink solids to the desired size, and mixed with carrier fluid. The mixed high solids content ink is then supplied to intermediate tank 220, where it is stored and supplied to ink tank 160 as needed. In heavier printing, intermediate tank 220 provides a reservoir of ink solids that are readily diluted and distributed to ink tank 160. As discussed above, when printing conditions are such that the fluids in ink tank 160 exceed that. its capacity, excess fluid is transferred to the intermediate tank 220 without filtering the paint solids. This excess fluid is then re-introduced into the system, without wasting ink solids or consuming filter elements.
    In one example, the introduction of additional high solids ink 205 into the printing system 200 is made to approximately match the amount of ink consumed by the printing system 200. For example, the HP Indigo press has been found to 500® consumes about 30 grams of ink solids per minute to support maximum coverage printing without pauses. Thus, in this example, the output of the dosage and blending unit 210 is at least 30 grams per minute. The dosing and mixing unit 210 is coupled to a printer control system and synchronized with the printing operation. Every time the amount of ink in the ink tank 160 falls below a predetermined threshold, a supply pump is operated for a certain period of time to supply a new amount of ink from the intermediate tank 220. In parallel, the amount of ink in the dosing and mixing unit 210 is monitored. When the ink level in the mixing unit passes a predetermined minimum, the mixing unit 210 is emptied into the intermediate tank 220, and a new batch of ink is prepared.
    In some situations, a print job can consume a large amount of ink solids, due to the nature of the print job, material, or ink coverage. In general, this results in a rapid drop in solids concentration in ink tank 160 as solids are extracted and deposited onto the substrate, and the liquid carrier returns from BID 115, figure 1 in print engine 225 to the ink tank 160. To compensate, an additional amount of ink (including both ink solids and carrier fluid) is added to ink tank 160. This can lead to an overflow of ink tank 160. However, the system shown in Figure 2 allows directing excess carrier via fluid return line 240, 242, 244 and valve system 230, 235, (in broken lines) to intermediate tank 220 and/or mixing unit 210. In this example, a first tube 240 connects ink tank 160 to a lower three-way valve 235. Lower valve 235 can selectively direct fluid from ink tank 160 to intermediate tank 220, via second tube 244, or metering and mixing unit. to 210, via third tube 242 and top valve 230.
    The fluid return line 240, 242, 244 is connected between the mixing unit 210 and at least one of the intermediate tank 220 and the ink tank 160, and allows the mixing unit 210 to directly receive the fluid via the return line of fluid 240, 242, 244 from at least one of buffer tank 220 and ink tank 160. Mixing unit 210 mixes the fluid with high solids ink 205 to produce a concentrate ink. This redistribution of low solids fluid to mixing unit 210 effectively recycles carrier fluid into the ink system.
    Because excess fluid from ink tank 160 contains ink particulates of the same color as in destination tanks 210, 220, it may be unnecessary to purify excess carrier before depositing it in tanks 210, 220. scheme efficiently recycles overflow from ink tank 160, and avoids unnecessary disposal of fluid in ink tank 160. If excess fluid from ink tank 160 is sent to carrier tank 165, filter 246 is used to remove paint solids or other particulates. This prevents cross-contamination between other ink colors from the carrier tank 165. The system mixing unit 210, intermediate tank 220, ink tank 160, and associated lines/valves is replicated for each ink color used in the printer. . As discussed above, all ink colors can come from the same carrier tank 165.
    In one test, the LEP printer with high capture and control efficiency, including mixing unit 210 and intermediate tank 220, was controlled using the algorithm described above. Which algorithm was implemented by a 226 printer controller and a number of sensors and actuators (not shown in figure 2. The LEP printer successfully printed, using an ink that was created by dispersing a high solids ink having more than 80 % solids. Additionally, the LEP printer successfully printed continuously with a high solids ink having 65% solids. Figure 3A is an illustrative graph showing excess carrier amounts for inks with different solids contents. The horizontal geometric axis of the graph shows image coverage per separation in percentage, with percentage, with lower percentages to the left and higher percentages to the right. Image coverage per separation varies depending on the image. For example, in the figure 3B a text image 300 may only include a black separation having an image coverage of about 6% of the total area of the image. gem. In Figure 3C a photograph 305 can include three or more separations (cyan, yellow, magenta, black) and have 40% or greater coverage for each separation. Images with greater image coverage consume more ink solids because the ink covers a larger portion of the substrate.
    The vertical geometric axis of the graph shows the amount of excess carrier fluid, measured in milligrams per print. The amount of excess carrier fluid for inlets with three different solids concentrations was measured. A first entry included 23% paint solids with balance carrier fluid. For 6% image coverage the first input generated an excess of about 25 milligrams of carrier fluid per print. For approximately 15% image coverage, the first input generated an excess of about 70 milligrams of carrier fluid per print. For 45% image coverage, the first entry generated an excess of nearly 200 milligrams of carrier per print. As printing proceeds, an additional amount of ink with 23% solids is added, and excess carrier fluid continues to be provided, and eventually can be discarded.
    The other two high solids paints can also be used for illustrative LEP systems: a first high solids paint at 65% solids and a second high solids paint at 85% solids. As shown in the graph, printing with 65% solids ink produces a small carrier fluid deficit when printing images with little image coverage per separation. In this case, carrier fluid may need to be added to the printing system. However, as image coverage increases and ink solids are consumed more quickly, the system starts generating small amounts of excess carrier fluid. For example, at 45% image coverage using 65% solids ink, an excess of approximately 20 milligrams of fluid per print results. This is the amount of rejects an order of magnitude smaller than using a paint with 23% solids.
    The 85% solids ink input shows much less dependence between the amount of carrier excess and image coverage. Incoming 85% solids ink maintains a small carrier fluid deficiency in all image coatings. Consequently, an amount of carrier fluid can be added periodically. However, there would be no excess carrier fluid to be discarded, because the amount of total carrier fluid added to the system corresponds to the amount consumed by the system. Using an 85% solids paint ensures no carrier remains in all modes of operation and coverage. Additionally, 85% solids ink is less bulky, and therefore less expensive to transport and store, than 23% solids ink. Figure 4 shows a simplified version of the LEP 200 printing system that accepts an input ink 205 with a deficit of carrier fluid. In some implementations, this does away with the need for an overflow tank 170, figure 2 and line from the ink tank 160, figure 2 to the carrier tank 165, figure 2. A quantity of fluid is added to the carrier tank 165 as per necessary to maintain printer operation. When operating with an ink with a high solids content, the deposition of the required amount of carrier fluid to the mixing unit 210, buffer tank 220, and ink tank 160 can be managed by an algorithm in the printer controller 226, which harvests data relating to consumption rate, solids concentration, liquid level, and other information. The algorithm then directs the amount of additional carrier fluid to the desired location.
    In the LEP 200 printing system described above, the use of ink with high solids content allows for a reduction in ink carrier consumption by a factor of 10 or more. This minimizes ink packaging, storage, and transport. In some implementations, this reduces the cost per printed page by up to 50%. Thus, the amount of carrier fluid rejects at the print site can be dramatically reduced, saving operator waste costs and significantly reducing the environmental impact of LEP printing. Figure 5 is a flowchart showing an illustrative method for producing high solids liquid electrophotographic inks for use in a printing system, in accordance with an example of the principles described herein. As shown in Figure 5, this method includes adding 550 a quantity of paint with high solids content and fluid to a mixing unit 210, the fluid being supplied directly from at least one of paint tank 160 and intermediate tank 220; and mixing 560 ink with high solids and fluid content in mixing unit 210 to produce a concentrated ink, which is supplied from ink tank 160 via intermediate tank 220. Figure 6 is a flowchart showing an illustrative method for producing electro inks -photographic liquids with a high solids content, for use in a printing system, according to an example of the principles described herein. As shown in Figure 6, the method includes adding 660 an amount of paint with high solids content to mixing unit 210; adding 670 an amount of fluid containing paint solids to mixing unit 210; and mixing 680 paint with high solids and fluid content in mixing unit 210 to produce a concentrated paint. Figure 7 is a flowchart showing an illustrative method for using high solids liquid electrophotographic inks. A future ink solids requirement is calculated 505. The calculation may comprise analyzing intended print jobs to determine media type, number of pages, and page coverage of a given color ink, to produce an anticipated demand as a function of time. An amount of ink with a high solids content and carrier fluid is added to the mixing unit in the LEP 510 printer and mixing unit to create a concentrated ink that is calculated to meet the future solids requirement in ink 515. The concentrated ink is transferred to intermediate tank 520. In the intermediate tank an additional dilution or other conditioning of the concentrated paint can be done. The ink tank concentrate is selectively added to the ink tank and diluted with additional carrier fluid to produce a printing ink with a predetermined solids concentration range of 525. The ink solids concentration can range from 1% to 10 % solids. For example, on a given system, paint solids can be selected by 2%. Printing ink is supplied from the ink tank to an LEP print engine, where ink solids from the printing ink are deposited onto a photoconductor and transferred to a substrate to produce 530 print. solids-free ink, which returns to ink tank 535. An additional amount of concentrated ink is added from the intermediate tank to the ink tank to replenish the ink solids consumed in the LEP print engine.
    In some implementations, high solids ink has an ink solids to carrier fluid ratio so as not to create excess carrier fluid during printing. An on-press capture and control system captures carrier fluid, and reconditions and returns carrier fluid to the system. For example, the capture and control system can condense carrier vapor into the carrier fluid, and separate the water from the carrier liquid. As discussed above, adding an amount of ink with high solids content and recycling carrier fluid can minimize or eliminate the creation of carrier fluid waste in the printing system. For example, the solids content can have an ink solids to carrier fluid ratio so as to create a carrier fluid deficit during printing. An amount of additional carrier fluid can be added to the printing system to make up for this deficit. When a high demand for ink solids creates an excessive fluid level in the ink tank, printing ink from the ink tank may return to the intermediate tank and/or mixing unit to prevent ink tank overflow . As this recycling is done in the same color system, there is no need to filter ink solids from the return fluid. This reduces leftover paint solids and filter element consumption. Figure 8 is a flowchart that further depicts carrier fluid management in an illustrative printing system that uses a high solids content ink. The future ink solids requirement is calculated 605. As discussed above, the future ink solids requirement is calculated using a number of inputs, including print job ink requirements, historical usage, and other factors. An amount of paint with a high solids content is added to the mixing unit to meet the future paint solids requirement 610. The amount of carrier fluid added to the mixing unit can come from either the intermediate tank or the paint tank, depending on the amount and distribution of carrier fluid in the printing system.
    When a medium image coverage causes a lack of carrier collection 615, the carrier fluid from the carrier tank is used for mixing 625. This addition of carrier tank carrier collection compensates for the low carrier collection rates when covering of the image is low. For example, when image coverage is low, and a smaller amount of ink solids is used, but the carrier fluid is recovered at approximately the same rate, this results in a gradual depletion of the carrier fluid. This situation is illustrated in Figure 3A for high solids paint having 65% solids. Below approximately 15% image coverage per separation, carrier fluid is consumed faster than ink solids, resulting in a carrier fluid deficit.
    When average image coverage results in excessive carrier collection 620, ink from the ink tank is used to mix ink concentrate 630. This situation is also illustrated in Figure 3A for high solids ink having 65% solids. . At an image coverage per separation above approximately 15%, ink solids are consumed faster than carrier fluid. This causes dilution of the ink that is returned to the ink tank. Returning the ink from the ink tank to the mixing unit mitigates this dilution. Additionally, as discussed above, there is no need to filter ink solids from the diluted ink that has been transferred from the ink tank to the mixing unit. The mixer then mixes the paint with high solids content and carrier fluid/ink to form the paint concentrate to meet the future paint solids requirement 635.
    Carrier fluid consumption is tracked over an extended period of time to measure carrier deficit or accumulation within the system. For example, carrier fluid consumption can be calculated against the amount of carrier collected 640. The printing system detects and tracks carrier fluid deficit. If low coverage print jobs continue for an extended period of time, the operator is notified to add an additional amount of fresh carrier to the 645 press when the shortfall drops below a pre-determined threshold.
    When the system determines an excess of carrier fluid in the system, the carrier consumption rate can be calculated versus the carrier tank volume 650. This allows the printing system to determine how much longer the carrier tank should accept excess carrier fluid. carrier fluid before its capacity is exhausted. When excess carrier fluid accumulates in the system, the excess carrier fluid can be used for dilution in intermediate tank 655. If excess carrier fluid continues to be collected for a longer period of time, the excess carrier fluid can be used for cleaning or for other activities, however other than printing 660. A notification to the operator may be given when a carrier fluid reaches a predetermined threshold. The predetermined limit can be expressed as a percentage of the carrier tank capacity, such as 80% or 90% of the carrier tank volume.
    In some configurations, a mitigation action can be provided in response to the accumulation or deficit of carrier fluid tracked by the system. For example, if there is an excess of carrier fluid in the system, a low coverage print job can be withdrawn to increase carrier fluid consumption relative to the amount of ink solids. Conversely, if there is a deficit of carrier fluid in the system, a high coverage print job can be withdrawn to increase ink solid consumption and produce some excess carrier fluid.
    Other actions can be taken to balance consumption of carrier fluid. For example, the operating parameters of the printer can be adjusted or the type of ink solids concentrate introduced into the system can be adjusted. In one implementation, if excess carrier fluid is accumulating in the system, a high solids ink having 85% solids can be introduced into the system. This provides a proportionately smaller amount of carrier fluid introduced into the system. Conversely, if there is a deficit in the system, a paint with a high solids content with a lower concentration of paint solids can be introduced into the system.
    In conclusion, a carrier fluid used by the LEP printer is purchased, produced as part of the ink, supplied to customers, passed through the printer, and finally disposed of. Excess carrier fluid can be a significant part of the printing cost. A printing system that uses liquid electrophotographic inks with a high solids content can reduce or eliminate excess carrier fluid. This can significantly reduce the cost of printing, reduce supply chain requirements, and minimize the creation of waste at the print site.
    The above description is presented solely for the purpose of illustrating and describing configurations and examples of the principles described. This description is not intended to exhaust or limit these principles to the precise form described.
    Many modifications and variations will be possible in light of the teachings given above.
    权利要求:
    Claims (11)
    [0001]
    1. Printing system (200), using inks with high solids content (205), characterized in that it comprises: - a mixing unit (210) to receive an ink with high solids content (205) and carrier fluid and produce a concentrated ink; - an intermediate tank (220) for receiving the concentrated ink from the mixing unit (210); - an ink tank (160) for receiving the concentrated ink from the intermediate tank (220) and producing printing ink; - a liquid electro-photographic printing motor (225) for receiving the printing ink from the ink tank (160); and - a fluid return line (240, 242, 244) which is connected between the mixing unit (210) and at least one of the intermediate tank (220) and the ink tank (160), the mixing unit ( 210) being configured to receive fluid via the fluid return line (240, 242, 244) from at least one of the intermediate tank (220) and the ink tank (160) and mix the fluid with the high ink content. solids (205) to produce the concentrated ink.
    [0002]
    2. System according to claim 1, characterized in that the ink with high solids content (205) is added to the system (200) according to an anticipated demand calculated from the intended printing tasks.
    [0003]
    3. System according to claim 1, characterized in that the fluid return line (240, 242, 244) additionally comprises a fluid connection between the ink tank (160) and the intermediate tank (220) and transfers fluid from the ink tank (160) to the intermediate tank (220).
    [0004]
    4. System according to claim 1, characterized in that ink solids are not filtered from the fluid passing from the ink tank (160) to the intermediate tank (220) and mixing unit (210).
    [0005]
    5. System according to claim 1, characterized in that it additionally comprises a carrier tank (165) containing carrier fluid, the carrier tank (165) being fluidly connected to the mixing unit (210).
    [0006]
    6. System according to claim 1, characterized in that the carrier fluid in the paint with high solids content (205) added to the system (200) is less than the consumption of the carrier fluid by the system (200) and produces a carrier fluid deficit in all printing conditions, the carrier fluid deficit being met by the addition of carrier fluid that is separated from ink with high solids content (205).
    [0007]
    7. Method for liquid electro-photographic printing using an ink with high solids content characterized by the fact that it comprises: - adding (550) ink with high solids content, a carrier fluid and an additional fluid to a mixing unit (210 ), the additional fluid being supplied directly from at least one of: an ink tank (160) and an intermediate tank (220); - mixing (560) the ink with high solids content and the additional fluid in the mixing unit (210) to produce a concentrated ink which is transferred to the ink tank (160) via the intermediate tank (220), in which to transfer the ink concentrate to the ink tank (160) comprises selectively adding (525) the concentrated ink from the intermediate tank (220) to the ink tank (160) where the concentrated ink is diluted with additional carrier fluid to produce a printing ink with a pre-determined range of paint solids concentrations.
    [0008]
    8. Method according to claim 7, characterized in that it additionally comprises using the printing ink for liquid electro-photographic printing.
    [0009]
    9. Method according to claim 7, characterized in that it further comprises: - calculating a future requirement (505) of solids in the ink based on the intended printing tasks; and - adding (515) an amount of paint with high solids content and additional paint to the mixing unit to create an amount of concentrated paint that is calculated to meet the future paint solids requirement.
    [0010]
    10. Method according to claim 7, characterized in that it further comprises: - supplying (530) printing ink from the printing tank (160) to a liquid electro-photographic print engine (225) where the solids ink from the printing ink are deposited on a photoconductor and transferred onto a substrate to produce a print; and
    [0011]
    11. return (535) the exhausted ink to the ink tank. 11. Method according to claim 7, characterized in that it further comprises returning the printing ink from the ink tank (160) to at least one of the intermediate tank (220) and the mixing unit (210) to prevent ink tank (160) overflow during periods of high demand for ink solids.
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    同族专利:
    公开号 | 公开日
    EP2670599A1|2013-12-11|
    WO2012105938A1|2012-08-09|
    US20130308984A1|2013-11-21|
    CN103328219A|2013-09-25|
    JP5620591B2|2014-11-05|
    EP2670599A4|2017-01-11|
    CN103328219B|2015-07-22|
    US9244389B2|2016-01-26|
    BR112013019351A2|2020-10-27|
    US9037047B2|2015-05-19|
    US20150301482A1|2015-10-22|
    JP2014510937A|2014-05-01|
    EP2670599B1|2019-07-03|
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    法律状态:
    2020-11-10| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2020-11-24| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-04-06| B25G| Requested change of headquarter approved|Owner name: HEWLETT-PACKARD DELOPMENT COMPANY, L.P. (US) |
    2021-06-08| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-06-29| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 31/01/2011, OBSERVADAS AS CONDICOES LEGAIS. PATENTE CONCEDIDA CONFORME ADI 5.529/DF, , QUE DETERMINA A ALTERACAO DO PRAZO DE CONCESSAO. |
    优先权:
    申请号 | 申请日 | 专利标题
    PCT/US2011/023192|WO2012105938A1|2011-01-31|2011-01-31|Printing systems utilizing inks with high solids content|
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