WO2022225515A1 - Réduction de la polarisation de tension en impression - Google Patents

Réduction de la polarisation de tension en impression Download PDF

Info

Publication number
WO2022225515A1
WO2022225515A1 PCT/US2021/028295 US2021028295W WO2022225515A1 WO 2022225515 A1 WO2022225515 A1 WO 2022225515A1 US 2021028295 W US2021028295 W US 2021028295W WO 2022225515 A1 WO2022225515 A1 WO 2022225515A1
Authority
WO
WIPO (PCT)
Prior art keywords
image
print
forming member
region
image region
Prior art date
Application number
PCT/US2021/028295
Other languages
English (en)
Inventor
Asaf Shoshani
Roy ENOCH
Avichai MARCOVICI
Vitaly Portnoy
Original Assignee
Hewlett-Packard Development Company, L.P.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett-Packard Development Company, L.P. filed Critical Hewlett-Packard Development Company, L.P.
Priority to PCT/US2021/028295 priority Critical patent/WO2022225515A1/fr
Publication of WO2022225515A1 publication Critical patent/WO2022225515A1/fr

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/1665—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat
    • G03G15/167—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat at least one of the recording member or the transfer member being rotatable during the transfer
    • G03G15/1675—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat at least one of the recording member or the transfer member being rotatable during the transfer with means for controlling the bias applied in the transfer nip

Definitions

  • Print apparatus may apply print agents to a substrate.
  • a print apparatus include Electro-photography (EP) printing devices, which may comprise Dry Electro Photographic or a Liquid Electro Photographic (LEP) print apparatus, and which utilise electrostatically charged or chargeable particles as printing materials. Such particles may be transferred to various surfaces in a print apparatus at least in part under a voltage bias.
  • EP Electro-photography
  • LEP Liquid Electro Photographic
  • Other examples of print apparatus comprise inkjet printers, bubble jet printers, and the like.
  • Figure 1 is a flowchart of an example method of operating a print apparatus
  • Figure 2 is a schematic diagram of an example print apparatus
  • Figure 3A and 3B are schematic diagrams of an example surface for an image transfer member
  • Figure 4 is a flowchart of another example method of operating a print apparatus
  • Figure 5 is an example graph demonstrating an effect of controlling a voltage bias on an image transfer member.
  • Figure 6 is a schematic diagram of an example machine-readable medium in association with a processor.
  • Electro-photography (EP) printing devices may form images on print media by placing a uniform electrostatic charge on a photoconductive surface (also termed a photoreceptor) and then selectively discharging the photoconductive surface in correspondence with images.
  • a photo charging unit may deposit a substantially uniform static charge on the photoconductive surface (which may be termed a photo imaging plate, or ‘PIP’, and may be curved around the surface of a drum).
  • a write head for example a laser, dissipates the static charge in selected portions of the image area on the photoconductive surface. The selective discharging forms a ‘latent image’ in electrostatic charges on the photoconductive surface.
  • Print agent may then be ‘developed’ onto the latent image of the photoconductive surface.
  • print agent is charged and does not adhere to the charged areas (having an opposite charge thereto), forming an image in print agent on the photoconductive surface in the uncharged regions.
  • the photoconductive surface will thereby acquire a developed print agent pattern on its surface and the photoconductive surface may provide an example of an image forming member as the term is used herein.
  • the print agent comprises a dry powder, for example a toner.
  • the print agent comprises an electrostatic ink composition (which may be more generally referred to as “an electronic ink” in some examples).
  • an electronic ink may comprise electrostatically charged or chargeable particles (for example, resin or toner particles which may be colored particles) dispersed in a carrier fluid.
  • the particles of a dry toner, or the particle component of the electronic ink may be electrically charged by virtue of an appropriate potential applied to the print agent in a print agent source.
  • an electrostatic ink composition is transferred to the photoconductive surface from a print agent source using a print agent applicator (which may be termed a Binary Ink Developer (BID) unit), which may present a substantially uniform film of the print agent to the photoconductive surface for example via a print agent application roller.
  • a print agent applicator which may be termed a Binary Ink Developer (BID) unit
  • BID Binary Ink Developer
  • a print agent image developed on the photoconductive surface may be transferred (or ‘offset’) to an image transfer member, or intermediate transfer member (ITM).
  • ITM image transfer member
  • the transfer of the print agent image from the photoconductive surface to the ITM is caused, at least in part, by a bias voltage applied to the ITM.
  • the bias voltage on the ITM is provided such that the charged print agent is attracted thereto. Transfer may also be facilitated by contact between the print agent layer and the ITM, and the ITM and the photoconductive surface may be urged together to cause such contact.
  • the ITM may for example comprise an endless loop surface, which may be a rubber ‘blanket’ arranged on a drum or cylinder.
  • the ITM is mechanically biased or urged towards the photoconductive surface such that, but for the presence of a layer of print agent on the photoconductive surface, it would be or is in contact with the photoconductive surface.
  • the ITM may disengage from the photoconductive surface in some states of the apparatus, while in other examples it remains in a stable, engaged position.
  • the print agent image may be heated for example to cause the particles therein to at least partially melt (and, in some LEP apparatus, to at least partially evaporate the carrier fluid), forming a fused image layer.
  • This image layer is then transferred to the surface of a print media (for example, a print media sheet or web) in the form of an image or text, for example, adhering to the colder surface thereof.
  • an image on a substrate or on an ITM may be built up in layers (so called ‘separations’) produced using different print agents.
  • the surfaces may be split into two image regions, wherein each image region is intended to produce a separate image.
  • the photoconductive surface and/or ITM are arranged on a cylinder or drum
  • two images may be printed in each full rotation (although in principle, there may be more than two image regions).
  • the image regions may be separated by a portion referred to as a ‘non-image region’ herein.
  • this may comprise a strip of a surface running the length of the cylinder, in which it is not intended for any image to be formed.
  • There may be a corresponding ‘non-image’ region on each of the photoconductive surface and the ITM. As these cylinders counter rotate, the two non-image areas may touch one another (or may become very close).
  • this region of both surfaces may receive some print agent.
  • a print agent source may be controlled so as to reduce or stop the transfer of print agent to the photoconductive surface at a point in the cycle corresponding to this region either by controlling the charge of the print agent or breaking contact between a print agent applicator and the photoconductive surface, or a combination thereof, this may not be precise.
  • the transfer process may be controlled electrostatically, but it may take time for charge to reduce, resulting in some transfer of print agent when it is not intended.
  • the print agent source may comprise a roller which is intended to disengage from the photoconductive surface while the non-image region is proximate thereto, but such a roller may be controlled so as to re-engage in the non-image region as such a re-engaging process may be associated with a ‘bounce’, and it may be intended to avoid the bounce occurring in the image region, as this may produce image quality issues such as banding. Therefore, the roller may re-engage in the non-image region, which could cause print agent transfer thereto. Any process which results in print agent being seen on the non-image region of the photoconductive surface may at least potentially result in print agent being transferred to the non-image region of the ITM.
  • Such unintended print agent transfer can build up over time. While the image regions of the ITM may be urged into contact with a substrate which is to be printed with an image, this may not be the case for the non-image region. Therefore, over time, even minimal transfer of print agent per cycle can build up as print agent deposits on the ITM. It has been noted that, once such deposits build up, they can start to transfer to substrates, for example as the edge of a deposited layer which has built up in the non image region tears off with a transferred image. This may then result in print quality issues. To avoid such print quality issues, the ITM may be periodically cleaned and/or at least a surface thereof may be replaced, but this takes time and resources, and the print apparatus may be out of service at such times.
  • print agents which may comprise particles carrying an electrostatic charge
  • image forming surface which is not a photoconductive surface prior to being transferred to the ITM
  • other printing techniques for example, using a printhead to eject print agent according to inkjet printing techniques or the like.
  • some print agent may accumulate on a non-image region of the ITM over time.
  • Figure 1 is an example of a method, which may be a method of operating a print apparatus.
  • the print apparatus in this example comprises an image forming member and an image transfer member (which may also be referred to as an intermediate transfer member, or ITM herein) which, in use of the apparatus, receives images from the image forming member.
  • the ITM comprises a first and a second image region, and the first and second image region are separated by a non-image region.
  • the image forming member may comprise a surface (e.g. a photoconductive surface), and the image forming member and the ITM may be provided on or as counter rotating drums or cylinders.
  • the ITM comprises an endless surface which is curved to form a cylinder comprising a seam portion and the non-image region is diametrically opposite the seam portion.
  • the non-image region may be referred to as the ‘anti-seam’ region.
  • the image forming member may comprise a print head, for example an ink jet print head.
  • the image forming member may comprise a surface onto which print agent has been distributed, for example using ink jet or bubble jet, or similar ink distribution technologies.
  • the method comprises, in block 102, during a first image region transit portion of a print cycle (i.e. a portion of the print cycle in which the first image region is adjacent to the image forming member), determining that the non-image region of the image transfer member is approaching the image forming member. In some examples, this may comprise determining that an image transfer process is coming to an end or has completed. In some examples block 102 may comprise determining that a distance that the ITM surface will travel before the non-image region is beside, or in some examples urged against, the image forming member is at or below a threshold. This may for example be determined by reference to a sensor, such as an encoder (e.g. a rotary encoder), a timer which be combined with a speed at which the ITM is moving, the position of a motor or other drive mechanism driving the movement, or any other apparatus which may monitor or determine the position of the ITM.
  • a sensor such as an encoder (e.g. a rotary encoder), a timer which be combined with
  • Block 104 comprises reducing a voltage bias on the image transfer member based on the determination.
  • a voltage bias level of the ITM which may for example be in the region of a few hundred volts, for example around 500 or 550 Volts, which is used as a voltage bias for the ITM when receiving at least part of an image from the image forming member.
  • the image may for example comprise text, a pattern or any other design.
  • this voltage bias may be reduced (for example temporarily) in order to reduce print agent transfer to the non-image region.
  • the voltage bias level may be reduced to around, or to less than, 100 Volts, for at least part of the portion of a print cycle which corresponds to the non-image region of the ITM being proximate to the image forming member.
  • Selectively reducing the voltage bias level for at least part of the portion of a print cycle which corresponds to the non-image region of the ITM being proximate to the image forming member may reduce the accumlation of print agent on this region, as the electrostatic attraction will be reduced.
  • Figure 2 is an example of a print apparatus 200 comprising an image forming member 202, an image transfer member (ITM) 204 associated with a voltage source 206, and a controller 208.
  • Figure 2 also shows, for reference, a print agent applicator 210. This is shown in dotted outline as it may be a replaceable component, and/or supplied separately to the other apparatus.
  • the image forming member 202 in the example of Figure 2 comprises a photoconductive surface 212, in this example a photoconductive imaging plate, or PIP, which is curved to form the surface of a cylinder, and joined at a seam region 214.
  • the cylinder is rotatably mounted.
  • the image forming member 202 in use of the apparatus 200, receives charged electrostatic print agent from the print agent applicator 210.
  • the print agent on the surface of the image forming member 202 is formed in a print agent pattern, for example comprising an image such as text or any other design.
  • the image forming member 202 may for example comprise a printhead, which may dispense charged print agent directly onto the ITM 204 in the print agent pattern and/or any surface on which an electrostatic print agent image may be formed, for example by a printhead or the like.
  • the ITM 204 in use of the apparatus 200, receives the charged electrostatic print agent from the image forming member 202.
  • the ITM 204 comprises, on a surface 216 thereof, a first and a second image region, wherein each of the first and second image region is to receive a respective print agent pattern, and further comprises a non-image region between the first and second image region.
  • the voltage source 206 is to apply a voltage bias in the region of a seam 218 on the ITM 204, which electrifies the surface 216.
  • the image forming member 202 and the ITM 204, in use of the apparatus 200 counter rotate as indicated by the dotted arrows.
  • the controller 208 in use of the apparatus 200, controls the voltage source 206 to provide a voltage bias to the ITM 204.
  • the voltage source 206 is electrically coupled to the surface 216 of the ITM 204.
  • the controller 208 may control the voltage source 206 to provide a first bias level while at least part of the first image region of the ITM 204 is adjacent to the image forming member 202 (e.g. during at least part of transfer of the print agent pattern to the first image region of the ITM 204), and a second bias level while at least part of the non-image region of the ITM 204 is adjacent to the image forming member 202.
  • the controller 208 may carry out the method of Figure 1.
  • the voltage source 206 may be able to respond rapidly to control signals, for example within microseconds (which may translate to around 1mm of travel of the surface of the ITM 204).
  • the print apparatus 200 may further comprise a sensor to determine the rotational position of the ITM, for example a rotary encoder, a timer, apparatus to monitor the position of a motor or other drive mechanism driving the movement, or any other apparatus which may monitor or determine the position of the ITM.
  • the controller 208 controls the voltage source 206 to provide the second bias level during a final part of the transit of the first image region past the image forming member 202.
  • the second bias level is provided during a final part of a transfer of the print agent pattern to the first image region of the ITM 204.
  • the voltage bias may be reduced before the image transfer is complete. Reducing the voltage bias to the second bias level during a final part of the transit of the first image region may allow some time for voltage to decay before the non-image region is brought into close alignment with the image forming member 202.
  • the controller 208 controls the voltage source 206 to provide the first voltage bias level during a final part of a portion of a print cycle in which the non-image region of the ITM 204 is adjacent to the image forming member 202.
  • the voltage bias may be increased before the next image transfer starts, to allow time for the voltage bias to build.
  • the print agent applicator 210 may, in use of the apparatus 200, engage with the image forming member 202 and present a substantially uniform layer of print agent to the surface of at least part of the image forming member 202.
  • the print agent applicator 210 may for example comprise a transfer roller which may be urged towards the image forming member 202 such that it is close thereto, for example being separated therefrom by the layer of print agent being applied.
  • This separation may be referred to as a ‘nip’, and the thickness of the layer of print agent transferred to the image forming member 202 may be controlled by controlling an electric field therebetween.
  • the print agent transfer roller may disengage from (i.e. be moved away from) the image forming member 202. This may be to avoid print agent transfer to ‘non-printing’ regions of the surface of the image forming member 202 (i.e. those regions in which an image is not formed), and/or to avoid the seam region 214, where the ends of a photoconductive plate forming the surface of the image forming member 202 meet to form the endless loop.
  • Figures 3A and 3B show an example of a surface 300 for providing an ITM (and which may be used to provide the surface 216 of the ITM 204).
  • Figure 3A shows the surface laid flat and
  • Figure 3B shows the surface 300 curved to form an endless surface.
  • the surface 300 in this example comprises a deformable ‘blanket’ of material, which, in use, may be formed about a rigid cylinder to provide an endless surface, or endless loop.
  • the surface 300 is at least somewhat electrically conductive, enabling it to be electrified by an applied bias voltage (referred to variously herein as the bias voltage or ITM bias voltage, and other similar variations).
  • the surface 216, 300 may comprise a multi-layer structure.
  • An example surface 216, 300 may have a fabric base layer, on top of which is provided a compressible layer, which allows the surface 216, 300 to deform as it is urged against other surfaces (e.g. the photoconductive surface 212 and/or a substrate) and may, for example, help to compensate for machine tolerances and print substrate thickness variations.
  • An electrically conductive layer for example comprising a metal, carbon or the like, may be provided on top of the deformable layer. In some examples, this electrically conductive layer may comprise conductive fibres or particles embedded in a rubber material. This layer may be electrified by the ITM bias voltage.
  • a relatively thin resilient layer e.g. comprising a rubber material, which may be the same material as is used to form the compressible layer and/or which may be relatively more readily compressible than the electrically conductive layer
  • a relatively thin resilient layer e.g. comprising a rubber material, which may be the same material as is used to form the compressible layer and/or which may be relatively more readily compressible than the electrically conductive layer
  • an outer coating layer may be provided to facilitate release of a print agent layer formed on the surface 300.
  • one or more of these layers may be absent or replaced.
  • any of the compressible layer, the resilient layer and/or the coating may be at least partially conductive with the inclusion of appropriately conductive materials (e.g. metals or carbon fibres/particles).
  • the surface 300 comprises a first image region 302, which is intended to receive an image from a corresponding portion of the surface of the image forming member 202 during a first half-cycle of the cylinder and a second image region 304 which is intended to receive an image from a corresponding portion of the surface of the image forming member 202 during a second half-cycle of the cylinder.
  • the first and second region 302, 304 are separated by a non-image region 306, which spans a midpoint of the surface 300 between its two ends.
  • clamping members 308a, 308b at either end of the surface 300 as shown in Figure 3A, there are clamping members 308a, 308b (although in some examples, a single clamping member may be provided and/or the clamping member may be a component which is separate from the surface 300).
  • the clamping member(s) 308 may engage with one another and/or the cylinder to hold the surface 300 in place on the ITM 204.
  • at least one of the clamping members 308a, b is electrically conductive, for example being formed of, or comprising, a metal.
  • a voltage source (for example, the voltage source 206 described in relation to Figure 2) may be electrically coupled, or electrically connected, to at least one clamping member 308, in order to electrify the surface 300.
  • the clamping members 308 in this example provide an electrical coupling or contact between the voltage source and the surface 300.
  • electrical contact with the surface 300 may be made at a plurality of discrete points along the clamping members 308.
  • the surface 300 may be curved to form an endless surface as shown in Figure 3B.
  • the curved surface 300 comprises a seam region 310, which may be similar to the seam region 218 shown in Figure 2, comprising the two clamping members 308a, 308b which are joined together and collectively labelled as 308.
  • the non-image region 306 is diametrically opposite the seam region 310.
  • the seam region 218, 310 of the ITM 204 provides a second region in which no image is to be formed. This region 218, 310 is subject to somewhat different conditions in use when compared to the non-image region 306.
  • the image forming member 202 may comprise a surface having a similar arrangement to that shown in Figure 3A and 3B, i.e. two image regions separated by a seam region and a non-image region which is arranged diametrically opposite the seam region.
  • the seam region 214 of the image forming member 202 and the seam region 218, 310 of the ITM 204 may be aligned in use such that they meet as the respective members 202, 204 rotate.
  • a print agent applicator (such as the print agent applicator 210 described in relation to Figure 2) may disengage from the image forming member 202 during transit of the seam region 214 past the print agent applicator.
  • the print agent applicator may disengage from the seam region of a photoconductive surface even when it does not do so in relation to the non-image region of such a surface. This may be because the seam region may comprise an uneven surface (for example, a ‘dip’) which may cause bouncing of the print agent applicator contact point, and could damage the sensitive photoconductive surface.
  • Figure 4 is an example of a method, which may be a method of operating a print apparatus, for example a print apparatus 200 as described in relation to Figure 2.
  • the method may be carried out by a controller of a print apparatus such as the controller 208 described in relation to Figure 2.
  • the method may be carried out during a printing job, for example as part of a print cycle.
  • the method may comprise, in block 402, setting a voltage set-point of a voltage source (e.g. the voltage source 206 of Figure 2) to a first voltage bias level.
  • a voltage source e.g. the voltage source 206 of Figure 2
  • this may comprise an image transfer voltage bias level, for example several hundred volts.
  • the first voltage bias level may be in the region of 550V.
  • Block 404 comprises carrying out a first part of an image transfer from an image forming member (e.g. a photoconductive member) to a first image region of an ITM while maintaining the voltage set point at the first voltage bias level.
  • the method first comprises, in block 406 and during a second part of the transfer of the image to the first image region, setting the voltage set- point of a voltage source to a second voltage bias level.
  • the second voltage bias level is lower than the first voltage bias level. For example, if the first voltage bias level is several hundred volts, then the second voltage bias level may be around 100V, or less than 100V. In one example, the first voltage bias level may be in the region of 550V and the second voltage bias level may be in the region of 10V.
  • the voltage setpoint may be changed while there is some image, for example a length of around 1cm of image, left to transfer. This allows time for the voltage on the ITM to degrade, and the time may be determined such that the voltage does not degrade excessively prior to the end of the image transfer.
  • the timing may depend on factors such as the bias voltage applied, the materials of the ITM, the age of the ITM, or the like.
  • the time at which the voltage bias is reduced may be based on a maximum image size.
  • a maximum image size For example, an example print apparatus in which each image region has a length of 510mm, this may be used to print images up to 510mm in length but an actual image being printed may be smaller than this. While the timing with which the voltage set point is changed could be tailored to the actual image size (for example, being timed so as to be X mm prior to the end of the image, where X may be a predetermined number), this may not be the case in all examples. Indeed, to ensure image transfer, it may be intended that the voltage is reduced at or after the end of an image transfer in some examples.
  • the voltage bias may be reduced after the full image is transferred, whereas where an image is at (or in some examples, shorter by less than the threshold amount) the maximum image length, the voltage may be reduced during the final part of an image transfer.
  • Block 404 and 406 may therefore comprise one example of a method for carrying out blocks 102 and 104 of Figure 1.
  • the method may comprise, in place of block 404, maintaining the voltage set point at the first voltage bias level during a first part of a first image region transit portion of a print cycle, wherein, during the first image region transit portion, the first image region is adjacent to the image forming member.
  • the method may comprise reducing the voltage set point prior to the end of the first image region transit portion.
  • the voltage reduction may be delayed until the start of the non-image region is adjacent to the image forming member, or the voltage may be reduced during image transfer as set out in relation to block 406. Such a method may still reduce build up of print agent on the non-image region 306. It may be noted that build-up of the print agent on the image region may be reduced by other methods, such as an occasional contact with a substrate.
  • the method further comprises, in block 408, maintaining the voltage set-point at the second voltage bias level during a first part of a non-image region transit portion of a print cycle, wherein, during the non-image region transit portion, the non-image region is adjacent to the image forming surface.
  • Block 410 comprises increasing the voltage bias set point to the first voltage bias level during a second part of the non-image region transit portion of the print cycle.
  • the method may comprise determining that the image region following the non-image region is approaching the image forming surface and increasing the voltage bias on the image transfer member based on the determination.
  • this may for example comprise restoring a voltage bias level to 550V before the end of the non-image region transit portion.
  • the voltage set point may be reset while there are still around 1 or 2cm of non-image region to transit in close proximity to the image forming member. This may allow the voltage bias time to build before image transfer begins.
  • ‘Close proximity’ in this example may mean that the distance between the non-image region of the ITM and the image forming member is minimised (i.e. at the minimum for the print cycle). For example, they may be in contact, or separated by (unintended) print agent which may be transferred from the image forming surface to the ITM as a result of their proximity.
  • the first voltage bias level may be maintained during the entirety of the second image region transit portion of the print cycle (wherein, during the second image region transit portion, the second image region is adjacent to the image forming member), during transit of the seam portion in close proximity to the image forming member, and during the first portion of the first image region transit portion of the next print cycle (e.g. during the first part of the next image transfer to the first image region).
  • the method may loop back to block 404.
  • this cycle may repeat many times over, for example hundreds or thousands of times.
  • the cycle may be disrupted, for example to insert null cycles, for cleaning, or the like.
  • Figure 5 shows a comparative example of a series of tests, indicating how thickness of print agent build up in a non-image region of an ITM (in this example, electronic ink in an LEP apparatus) increases with number of impressions (wherein an impression is the transfer of a print agent pattern through the apparatus).
  • the y axis is indicative of the thickness in microns (pm) and the x axis is indicative of the number of thousands of impressions (kimps).
  • a first line 502 (associated with the error bars having a round marker) indicates how the thickness increased during use when a single bias level (in this example, 550V) was used as the ITM bias for the entire print cycle.
  • a second line 504 (associated with the error bars having a square marker) indicates how the thickness increased during use when a first bias of 550V was used for the majority of the image transfer portion of the print cycle and a second, lower, bias level of 10V was used for part of the non-image region transit portion of the print cycle.
  • the voltage was reduced from 550V to 10V 1cm before the end of the image transfer onto the first image region and increased back to 550V 2cm before the end of the transit of the non-image region in close proximity with the photoconductive surface.
  • the thickness of the layer was measured using a confocal microscope, in the same manner for both trials.
  • the thickness of the layer was considerably reduced by using the methods set out herein. This may reduce the frequency of servicing of a print apparatus and/or replacing components thereof, which would otherwise have associated costs and downtime.
  • Figure 6 is an example of a tangible, non-transitory, machine readable medium 600 in association with a processor 602.
  • the processor 602 is a processor 602 of a printing device, for example the print apparatus 200 of Figure 2.
  • the machine readable medium 600 comprises (or stores) instructions 604 which, when executed by the processor 602, cause the printing device to carry out operations.
  • the instructions 604 comprise instructions 606 which, when executed, cause the printing device to, during a print cycle of a printing process, determine that a non image region of a rotating endless surface of an ITM of the print apparatus is proximate to the rotating endless surface of an image forming member.
  • the non image region may be between two image regions as discussed above.
  • the non-image region may be opposite a seam portion of the ITM.
  • Proximate may, in this case, refer to a point of closest approach between the non-image region of the ITM and the image forming member, or may refer to a point in the print cycle before, in some examples just before, the point of closest approach, for example a few centimetres, or a few millimetres before the point of closest approach, as discussed above.
  • the instructions 604 further comprise instructions 608 which, when executed by the processor 602 (e.g. a processor of a printing device), cause a printing device to reduce a voltage bias of the endless surface of the ITM for at least part of a period in which the non-image region of the endless surface of the ITM of the print apparatus is proximate to the endless surface of the image forming member.
  • the processor 602 e.g. a processor of a printing device
  • the instructions 604 further comprise instructions which, when executed by the processor 602, cause the printing device to determine that an image region of the rotating endless surface of the ITM of the print apparatus is proximate to the rotating endless surface of the image forming member, wherein the image region follows the non-image region in the direction of rotation.
  • the instructions 604 further comprise instructions which, when executed by the processor 602, cause the printing device to increase the voltage bias of the endless surface of the ITM for at least a period in which the image region of the endless surface of the ITM of the print apparatus is proximate to the endless surface of the photoconductive member. For example, this higher voltage bias may be maintained until it is determined that the non-image region of the endless surface of the ITM of the print apparatus is again proximate to the endless surface of the photoconductive member.
  • the instructions may, when executed, control a print apparatus to carry out at least one block of Figures 1 or 4, or other methods set out above. In some examples, the instructions may provide at least part of the controller 208.
  • Examples in the present disclosure can be provided as methods, systems or machine-readable instructions, such as any combination of software, hardware, firmware or the like. Such machine-readable instructions may be included on a computer readable storage medium (including but not limited to disc storage, CD-ROM, optical storage, etc.) having computer readable program codes therein or thereon.
  • a computer readable storage medium including but not limited to disc storage, CD-ROM, optical storage, etc.
  • FIG. 1 The present disclosure is described with reference to flow charts and/or block diagrams of the method, devices and systems according to examples of the present disclosure. Although the flow diagrams described above show a specific order of execution, the order of execution may differ from that which is depicted. Blocks described in relation to one flow chart may be combined with those of another flow chart. It shall be understood that each block in the flow charts and/or block diagrams, as well as combinations of the blocks in the flow charts and/or block diagrams can be realized by machine readable instructions.
  • the machine-readable instructions may, for example, be executed by a general-purpose computer, a special purpose computer, an embedded processor or processors of other programmable data processing devices to realize the functions described in the description and diagrams.
  • a processor or processing apparatus may execute the machine-readable instructions.
  • functional modules of the apparatus and devices may be implemented at least in part by a processor executing machine readable instructions stored in a memory, or a processor operating in accordance with instructions embedded in logic circuitry.
  • the term ‘processor’ is to be interpreted broadly to include a CPU, processing unit, ASIC, logic unit, programmable gate array, etc.
  • the methods and functional modules may all be performed by a single processor or divided amongst several processors.
  • Such machine-readable instructions may also be stored in a computer readable storage that can guide the computer or other programmable data processing devices to operate in a specific mode.
  • Such machine-readable instructions may also be loaded onto a computer or other programmable data processing device(s), so that the computer or other programmable data processing device(s) perform a series of operations to produce computer-implemented processing, thus the instructions executed on the computer or other programmable devices realize functions specified by block(s) in the flow charts and/or block diagrams.
  • teachings herein may be implemented in the form of a computer software product, the computer software product being stored in a storage medium and comprising a plurality of instructions for making a computer device implement the methods recited in the examples of the present disclosure.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

Dans un exemple, un appareil d'impression comprend un élément de formation d'image et un élément de transfert d'image servant à recevoir des images provenant de l'élément de formation d'image, l'élément de transfert d'image comprenant une première et une seconde région d'image, et les première et seconde régions d'image étant séparées par une région de non-image. Dans un exemple, un procédé peut consister, pendant une première partie de transit de région d'image d'un cycle d'impression dans lequel la première région d'image est adjacente à l'élément de formation d'image, à déterminer que la région de non-image de l'élément de transfert d'image se rapproche de l'élément de formation d'image et à réduire une polarisation de tension sur l'élément de transfert d'image sur la base de la détermination.
PCT/US2021/028295 2021-04-21 2021-04-21 Réduction de la polarisation de tension en impression WO2022225515A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2021/028295 WO2022225515A1 (fr) 2021-04-21 2021-04-21 Réduction de la polarisation de tension en impression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2021/028295 WO2022225515A1 (fr) 2021-04-21 2021-04-21 Réduction de la polarisation de tension en impression

Publications (1)

Publication Number Publication Date
WO2022225515A1 true WO2022225515A1 (fr) 2022-10-27

Family

ID=83722466

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2021/028295 WO2022225515A1 (fr) 2021-04-21 2021-04-21 Réduction de la polarisation de tension en impression

Country Status (1)

Country Link
WO (1) WO2022225515A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5450180A (en) * 1988-11-02 1995-09-12 Canon Kabushiki Kaisha Image forming apparatus having constant current and voltage control in the charging and transfer regions
US5812904A (en) * 1995-09-19 1998-09-22 Samsung Electronics Co., Ltd. Image forming apparatus and method for controlling charging potential differently between image forming area and non-image forming area of photosensitive drum
US20060164489A1 (en) * 2005-01-26 2006-07-27 Ramon Vega Latent inkjet printing, to avoid drying and liquid-loading problems, and provide sharper imaging
US10185258B2 (en) * 2016-07-01 2019-01-22 Canon Kabushiki Kaisha Image heating apparatus and image forming apparatus for controlling a temperature of a first heating element and a second heating element
US10384471B2 (en) * 2013-01-11 2019-08-20 Ceraloc Innovation Ab Digital binder and powder print

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5450180A (en) * 1988-11-02 1995-09-12 Canon Kabushiki Kaisha Image forming apparatus having constant current and voltage control in the charging and transfer regions
US5812904A (en) * 1995-09-19 1998-09-22 Samsung Electronics Co., Ltd. Image forming apparatus and method for controlling charging potential differently between image forming area and non-image forming area of photosensitive drum
US20060164489A1 (en) * 2005-01-26 2006-07-27 Ramon Vega Latent inkjet printing, to avoid drying and liquid-loading problems, and provide sharper imaging
US10384471B2 (en) * 2013-01-11 2019-08-20 Ceraloc Innovation Ab Digital binder and powder print
US10185258B2 (en) * 2016-07-01 2019-01-22 Canon Kabushiki Kaisha Image heating apparatus and image forming apparatus for controlling a temperature of a first heating element and a second heating element

Similar Documents

Publication Publication Date Title
US20090232530A1 (en) Image forming apparatus
US6591072B2 (en) Image forming apparatus with changeable toner returning electric field application period
EP2670597B1 (fr) Imprimantes, procédés et appareil pour former une image sur un substrat d'impression
US20060039711A1 (en) Image forming apparatus
US5940661A (en) Image forming apparatus with a charging member which removes smears on an image forming member
US20110103814A1 (en) Image forming apparatus and image forming method
US20100226702A1 (en) Hard Image Forming Apparatuses and Methods
WO2022225515A1 (fr) Réduction de la polarisation de tension en impression
US7792443B2 (en) Image forming apparatus controlling the voltage applied to the developing member
US20150306866A1 (en) Printers, Methods and Apparatus to Form an Image on a Print Substrate
US20090311006A1 (en) Image forming apparatus
US6690898B2 (en) Image forming apparatus with movable cleaning element
JP2003091146A (ja) 画像形成装置
JP5838767B2 (ja) 画像形成装置
US8953971B2 (en) Image forming apparatus
US20190346799A1 (en) Detecting contact between print apparatus components and photoconductive surfaces
US11971666B2 (en) Image forming apparatus and control method, that control charging voltage according to positions of developing roller
US11829087B2 (en) Image forming apparatus with image bearing members having different surface layer thicknesses
US7970319B2 (en) Charging apparatus, print engine that incorporates the charging apparatus, and image forming apparatus that incorporates the print engine
JP7140553B2 (ja) 画像形成装置
JP2008191183A (ja) 液体現像剤供給装置，及び画像形成装置
WO2023063955A1 (fr) Entretien de blanchets d'impression
JP3484814B2 (ja) 現像装置
CN118119896A (zh) 打印机和固定图案化板
JP2013156418A (ja) 画像形成装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21938094

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21938094

Country of ref document: EP

Kind code of ref document: A1