JP2004171022A - Imaging system and intermediate transfer blanket for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily attachable/detachable intermediate transfer member that is suitable for toner liquid. <P>SOLUTION: The intermediate transfer members 30, 102, and 104 include a drum 30 having an installation recess made in it, and an intermediate transfer blanket 104 set on the drum 30. The blanket 104 has on its one side a transfer face 109 for receiving a toner image. It optionally has an adhesive layer 126 on the opposite side. Additionally, it includes a mounting device 106 for installation which is attached to one of the edges of a transfer member formed of layers and which is fitted in the installation recess of the drum. The transfer blanket 104 is removably fixed on the drum 30. <P>COPYRIGHT: (C)2004,JPO

Description

Field of the invention

  The present invention relates to image formation, and more particularly to an image transfer apparatus for use in electrostatic imaging (image formation) using an intermediate transfer blanket.

Background of the Invention

  The use of intermediate transfer members in electrostatic imaging is well known.

  Various types of intermediate transfer members are known, for example, U.S. Patent Nos. 3,862,848, 4,684,238, 4,690,539, 4,531,825 and related As set forth in the application, all of these specifications are incorporated herein by reference.

  Belt-type intermediate transfer members used in electrophotography are known in the art and are described, inter alia, in U.S. Patent Nos. 3,893,761, 4,684,238, and 4,690,539. However, these specifications are incorporated herein by reference.

  It is also well known to use a member that includes an intermediate transfer member and a transfer blanket for offset ink printing. Although such blankets are suitable for transferring ink, they generally have the characteristic that they cannot be used for liquid toner imaging.

Summary of the Invention

  According to a first aspect of the present invention, there is provided an improved image transfer device using an improved intermediate transfer member.

  The present invention further provides, in a second aspect, an improved image transfer member for use in an imaging apparatus, particularly an image forming apparatus using electrostatically charged toner.

  The present invention further provides, in a third aspect, an improved image transfer blanket for use as part of an image transfer member in an imaging apparatus, particularly an image forming apparatus using electrostatically charged toner.

  According to a preferred embodiment of the present invention, preferably, an image surface having an image that is a toner image formed on the image surface, and a toner image is received from the image surface, from which the toner image is sequentially delivered. An intermediate transfer member, the intermediate transfer member including a drum having a mounting recess formed therein, and an intermediate transfer blanket mounted on the drum, wherein the blanket has one surface. A transfer surface for receiving the toner image, a layered transfer portion having a layer of adhesive, preferably on the opposite side, and a drum mounting member mounted on only one edge of the layered transfer member; An imaging device is provided, which includes a mounting fixture (fixture) adapted to be combined with a recess, and is provided (mounted) so that a transfer blanket can be detached from a drum.

  In a preferred embodiment of the invention, at least a portion of the surface of the layered transfer portion, opposite the transfer surface, is adhered to the drum.

  Preferably, the layered transfer portion comprises a conductive layer under the transfer surface and a conductive layer attached to one edge of the transfer portion and electrically connected to the conductive layer. Includes mounting (mounting) fittings that include the elements.

  In a preferred embodiment of the present invention, the conductive component (element) preferably comprises at least one "L" -shaped finger-like extension, in contact with the drum, wherein the drum is The voltage for operating to transfer the toner image from the image surface to the transfer surface is charged. Preferably, said at least one "L" -shaped extension is a first portion extending perpendicular to a layered transfer portion, and is attached to and substantially perpendicular to the first portion. And a second member extending substantially parallel to and away from the layered transfer portion.

  Preferably, the mounting (mounting) recess further comprises a recess for receiving said second portion.

According to a preferred embodiment of the present invention, furthermore, a layered transfer part having a transfer surface on one side and a layered transfer part applied for mounting (mounting) a blanket on a drum A substantially rectangular intermediate transfer blanket is provided that includes a mounting fixture attached to only one edge of the intermediate transfer blanket.

  Preferably, the layered transfer portion comprises a conductive layer located below the transfer surface, and the mounting fixture is attached to one edge of the transfer member and is electrically connected to the conductive layer. Including a conductive element.

  Preferably, the conductive element comprises at least one "L" -shaped finger-like extension, the extension preferably comprising a first portion extending in a direction perpendicular to the layered transfer portion; A second portion mounted substantially vertically to the first portion and extending substantially horizontally away from the layered transfer portion.

  In a preferred embodiment of the invention, the layered transfer portion comprises a matching layer formed of a material having a Shore A hardness of less than 65, preferably less than about 50 and greater than about 30.

Preferably, the transfer surface is a release layer for the toner.
According to a preferred embodiment of the present invention, further comprising a layered transfer portion having a transfer surface on one surface and including a conductive layer below the transfer surface, and attached to one edge of the transfer portion. And a conductive element electrically connected to the conductive layer.

  According to a preferred embodiment of the present invention, further, the transfer surface on one side and a conformable layer having a Shore A hardness of less than about 65, preferably less than about 50 and preferably more than about 30. A layered intermediate transfer member and blanket are provided.

  According to a preferred embodiment of the present invention, furthermore, the transfer surface on one side of the blanket and at least 80 ° C, preferably above 100 ° C, more preferably above 120 ° C, most preferably A layered intermediate transfer blanket is provided which comprises a layer of adhesive on the opposite side of the blanket, which is stable at temperatures above 150 ° C.

  In a preferred embodiment of the present invention, the transfer surface on one side of the blanket further comprises an opposite of the blanket having a Shore A hardness of less than 90, more preferably less than 45, and most preferably less than 25. And a soft layer on one of the sides.

  In a preferred embodiment of the invention, the soft layer comprises an acrylic polymer.

  In a preferred embodiment of the invention, the layered transfer portion comprises a layer of adhesive opposite the transfer surface.

According to a preferred embodiment of the present invention, there is further provided an imaging surface having a liquid toner image composed of toner particles and a carrier liquid, and an intermediate transfer component that receives the toner image from the imaging surface and from which the image is sequentially transferred. Wherein the intermediate transfer component comprises a layered transfer portion having a transfer surface on one surface for receiving an image of the toner, and a material underlying the transfer surface and at least partially leached by the carrier liquid. A resilient layer, preferably comprising at least partially hydrolyzed polyvinyl alcohol, and substantially impermeable to the carrier liquid, the resilient layer and the transfer surface. An imaging device is provided for performing an imaging process, including an intermediate, barrier layer.

  According to a preferred embodiment of the present invention, furthermore, a transfer surface, a resilient layer underlying the transfer surface and at least partially leached by liquid hydrocarbons, preferably at least partially Intermediate transfer comprising a layer comprising a hydrolyzed polyvinyl alcohol, substantially impermeable to liquid hydrocarbons, a resilient layer and a barrier layer intermediate the transfer surface A member is provided.

  According to a preferred embodiment of the present invention, furthermore, a transfer surface, a resilient layer underlying the transfer surface and at least partially leached into the carrier liquid, preferably at least partially Containing toner particles and a carrier liquid, including a polyvinyl alcohol that has been hydrolyzed to a surface, substantially impermeable to the carrier liquid, including a resilient layer and a barrier layer intermediate the transfer surface. A layered intermediate transfer member is provided for receiving a liquid toner image.

  According to a preferred embodiment of the present invention, there is provided an imaging surface having a liquid toner image including toner particles and a carrier liquid, and an intermediate transfer member receiving the toner image from the imaging surface and sequentially transferring the image therefrom. Wherein the intermediate transfer member includes a layered transfer portion having a transfer surface on one surface for receiving an image of the toner, and an elastic member under the transfer surface and including material that interferes with the operation of the imaging process. A resilient layer, and preferably at least partially hydrolysed polyvinyl alcohol, which is substantially impermeable to the interfering material contained in the resilient layer and resilient. There is provided an imaging apparatus for performing an imaging process including a layer having a property and a barrier layer located in the middle of a transfer surface.

  In a preferred embodiment of the invention, the interference material is a gas and the barrier layer is a barrier layer for the gas.

  According to a preferred embodiment of the present invention, further comprising a transfer surface, a resilient layer below the transfer surface, and preferably at least partially hydrolyzed polyvinyl alcohol, A layered intermediate transfer member is provided that includes a layer that is substantially impermeable to liquid hydrocarbons and resilient and a barrier layer intermediate the transfer surface.

  According to a preferred embodiment of the present invention, there is further provided a transfer surface, a resilient surface underlying the transfer surface and releasing gas, and preferably at least partially hydrolyzed polyvinyl. A layered intermediate transfer member is provided comprising an alcohol-containing, substantially gas impermeable, resilient layer and a barrier layer intermediate the transfer surface.

  According to a preferred embodiment of the present invention, there is further provided a transfer surface, a resilient layer underlying the transfer surface and made of a material that is at least partially leached into the carrier liquid, A toner particle and carrier comprising at least partially hydrolyzed polyvinyl alcohol and substantially impermeable to the carrier liquid and comprising a resilient layer and a barrier layer intermediate the transfer surface; An intermediate transfer member is provided for forming a layer for receiving an image of a liquid toner comprising a liquid.

  The present invention will be more fully understood and appreciated from the following detailed description, taken in conjunction with the following drawings.

Detailed Description of the Preferred Embodiment

  Reference is now made to FIGS. 1 and 2, which illustrate a multicolor electrostatic imaging system constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIGS. 1 and 2, an imaging sheet, preferably an organic photoreceptor 12, is provided, typically mounted on a rotating drum 10. The drum 10 is driven by a motor or the like (not shown) about its axis in the direction of the arrow 18, preferably in the art such as a corotron, scorotron or roller charger, and is provided with a sheet-like photoreceptor 12. It rotates past the charging device 14, which is another suitable charging device applied to charge the surface. The reproduced image is focused by the imager (imager) 16 on the charged surface 12 and at least partially discharges the photoconductor in the exposed area by an electrostatic latent image. To form Thus, the latent image usually includes a range of the first potential and a base range of another potential.

  The photoreceptor sheet 12 uses any suitable arrangement of layers of material, as is known in the art, but in a preferred embodiment of the photoreceptor sheet, some of the layers are removed from the edges of the sheet. Then, the installation on the drum 10 is promoted.

  This preferred photoreceptor sheet and a preferred method of placing it on drum 10 is described in Belinkov et al., Commonly assigned U.S. patent application Ser. No. 08 / 301,775, filed Sep. 7, 1994. Imaging Apparatus and Photoreceptors Therefor ", and claims in other countries, the disclosure of which is incorporated herein by reference. Also, the photoreceptor 12 is placed on the drum 10 and forms a continuous surface. Further, the photoreceptor 12 may be, for example, a non-organic photoconductor based on a mixture of selenium (Se).

  The imaging device 16 may include other devices, such as those known in the art, such as a modulated laser beam scanning device, an optical focusing device for writing a copy on a drum, and the like. An imaging device.

  In the preferred embodiment of the present invention, a multicolor liquid developer / spray / assembly 20, a developing assembly 22, a color-specific cleaning blade assembly. (Cleaning blade assembly for color) 34, background (base) cleaning station 24, charging squeegee (rubber roller) 26, background discharge device 28, intermediate transfer member 30, and cleaning device 32, and if necessary, A neutralizing lamp assembly 36 is associated with the drum 10 and the photoreceptor sheet 12.

  The development assembly 22 preferably includes a development roller 38. The development roller 38 is preferably spaced from the photoreceptor 12, thereby forming a gap, typically 40-150 microns (micrometers), of the image and the background (background or base) of the image. It is charged to a potential in the middle of the range. The development roller 38, when maintained at an appropriate voltage, thus applies electrolysis to facilitate the development of the electrostatic latent image.

  Development roller 38 typically rotates in the same direction as drum 10, as indicated by arrow 40. This rotation causes the surface of the sheet 12 and the development roller 38 to have opposite speeds in the gap between them.

  Its operation and construction is described in detail in U.S. Pat. No. 5,117,263 (the disclosure of which is incorporated herein by reference) and the multicolor liquid developer spray assembly 20 is described in US Pat. A spray of liquid toner containing charged colored toner particles is directed at a portion of the development roller 38 and a portion of the photoreceptor 12 or directly between the photoreceptor 12 and the development roller 38. The assembly 20 is mounted (mounted) on the shaft 42 so that the assembly 20 can be turned in such a manner as to be directed to the developing portion 44 of FIG. Alternatively, the assembly 20 is fixed. Preferably, the spray is directed to a portion of development roller 38.

  The color-specific cleaning blade assembly 34 is operatively associated with a developer (development) roller 38 for separately removing residual amounts of each colored toner remaining after development. Each of the blade assemblies 34 is selectively operatively associated with the developer roller 38 only when the corresponding color toner is supplied to the development area 44 by the spray assembly 20.

  The structure and operation of the cleaning blade assembly is described in PCT Publication WO 90/14619 and US Pat. No. 5,289,238, the contents of which are incorporated herein by reference.

  Each cleaning blade assembly 34 has an independent collection of toner removed from the developer roller 38 by the cleaning blade assembly 34 to prevent contamination of the various developers due to color mixing. It includes a toner directing member 52 that serves to direct the containers 54,56,58,60. The toner collected by the collection container is recycled to the corresponding toner reservoir (55, 57, 59, 61). The final toner directing member 62 always connects the developer roller 38, where the collected toner is supplied to a collection container 64, which then operates to separate the relatively clean carrier liquid from the various colored toner particles. The liquid is supplied to a reservoir (reservoir) 65 through a separator (separator) 66. The separator 66 is generally of the type described in U.S. Pat. No. 4,985,732, the disclosure of which is incorporated herein by reference.

  In a preferred embodiment of the present invention, the speed of imaging is very high, as described in US Pat. No. 5,255,058, the disclosure of which is incorporated herein by reference. A background (base) cleaning station 24 is provided, which typically includes a reverse roller 46 and a liquid spray device 48. Reverse roller 46, which rotates in the direction indicated by arrow 50, is electrically biased to a potential intermediate the image and background portions of photoconductive drum 10, but at a different potential than the development roller. Reverse roller 46 is preferably spaced from photoreceptor sheet 12, thereby forming a gap, typically between 40 and 150 microns.

  Liquid spray device 48 is operative to receive liquid toner from reservoir 65 via conduit 88 and preferably to supply a pigment-free carrier liquid to the gap between sheet 12 and reverse roller 46. The liquid supplied by the liquid spray device 48 is replaced by the liquid removed from the drum 10 by the development assembly 22 so that the reverse roller 46 electrophoreses the charged colored toner particles by electrophoresis. It can be removed from the background (base) portion of the image. Excess liquid is removed from the reverse roller 46 by a liquid directing member 70 that continuously mates with the reverse roller 46 to collect toner particles of various colors including the extra liquid, and the toner particles are collected. It is supplied to the reservoir 65 via the container 64 and the separator 66.

  The devices shown at 46, 48, 50, 70 are not required in low speed systems, but are preferably included in high speed systems.

  Preferably, an electrically biased squeegee roller 26 is pressed against the surface of sheet 12 to remove liquid carriers from background areas, compact the image and reduce liquid Operate to remove carriers. The squeegee roller 26 is preferably formed of a resilient, slightly conductive polymeric material, as is well known in the art, and preferably comprises It is charged to a potential of several hundred to several thousand volts to the same polarity as the polarity of the charging.

  In a first preferred embodiment, the squeegee roller molds a soft polyurethane rubber coating on a metal core, coats the molded core with a conductive lacquer, and lowers the lacquer. Made by coating with a conductive elastomer. Also, in the second embodiment, the molded coating can be made of a controlled conductive elastomer and the lacquer can be omitted. In a third embodiment, a single layer of controlled conductive elastomer is used and the outer layers are omitted.

  In a first embodiment of a squeegee (rubber roller), the metal core is cleaned, dissolved in, for example, an equal volume of methyl ethyl ketone and coated with a rubber and metal adhesive such as CILBOND 49 SF (Compounding Ingredients Limited, UK). And dried at 110 ° C. for 1 hour. The outer mold, having a diameter of about 9.5 mm larger than the core, can be dip coated with a release agent, for example, a mixture of Syl-Off 7600 (Dow Corning) 10, Syl-Off 7601 1, n-hexane 150. And then cured at 110 ° C. for 1 hour. The space between the core and the mold (preheated to 70-80 ° C.) is filled with polyurethane rubber for casting (CIL A 20, Compounding Ingredients Limited, UK), which is for 16 hours at 80 ° C. in vacuum. After preheating, it is heated at 120 ° C. for another hour. The polyurethane is cured at 135 ° C. for 8 hours. After cooling and removing the coated core from the mold (with the help of a solvent such as Isopar when removing), the cast material is ground to a size of about ± 5 microns. The preferred hardness of the coating is about 20 Shore A, but this hardness varies from 15 to 40 Shore A hardness depending on the amount of liquid that is desired to be removed.

  The polished surface is cleaned with acetone, preferably pre-filtered with a lint-free cloth, and given a thickness (after drying) of about 30 microns (after drying) of a conductive lacquer (preferably H322). (Lord Corporation, USA) 3 parts and ethyl acetate 1 part), preferably dip-coated.

50 parts of Fomrez 50 (Witco. Corp., USA) dissolved in ethyl acetate 75, 3 parts of DC193 (Dow Corning), diphenylmethane 4,4 'diisocyanate (MDI) (Desmodor 44V20 manufactured by Bayer, Germany) about 6 parts The top layer with the parts added is filtered and dip coated multiple times over the lacquer coating to achieve a coating thickness of 60-70 microns. The coated squeegee is dried at room temperature and cured at 140 ° C. for 2 hours. The preferred hardness of the material forming the outer layer is about 30-35 Shore A, and this hardness can be adjusted by varying the proportion of MDI in the coating. Coating is ^{10 8} ~10 10 Ω-cm has a resistivity in the range of, 2 to 3 × preferred value from ^{1~3 × 10 8 10 9 Ω-} cm.

In a second embodiment of the squeegee roller, the casting cover for the core preferably has a hardness (15-30 Shore A, preferably 20 Shore A) and a resistivity (1-10 × 10 ⁶ Ω-cm).

  This material can be an oil resistant rubber such as polyurethane, nitrile, and the like. Polyurethanes with selected resistivity and hardness are available from Marthane Products (USA). After being cast as described above, the coating is polished to the appropriate size and finish and coated with a top layer made in the same manner as the top layer of the first embodiment.

  In a third embodiment of the squeegee roller, the top layer is omitted and the conductive elastomer is cast, preferably to precise dimensions.

  The discharge device 28 operates to irradiate the sheet 12 with light that discharges the voltage remaining on the sheet 12, primarily to reduce electrical breakdown and improve image transfer to the intermediate transfer member 30. The operation of such a device in a black and white system is described in U.S. Patent No. 5,280,326, the disclosure of which is incorporated herein by reference.

  FIGS. 1 and 2 further illustrate that the multicolor toner spray assembly 20 typically receives independent supplies of colored toner from four different reservoirs 55, 57, 59, 61. FIG. FIG. 1 shows reservoirs 55, 57, 59, 61 of four different colored toners, each typically including yellow, magenta, cyan, and optionally black. Pumps 90, 92, 94, 96 are provided along corresponding conduits 98, 101, 103, 105 to provide the desired amount of pressure to supply the colored toner to the multicolor spray assembly 20. . Also preferably, a multi-level toner spray assembly 20, a three level spray assembly, provides up to six different reservoirs (custom color toners) in addition to the standard process colors. (Not shown)).

  Suitable types of toners for use with the present invention are described in Example 1 of U.S. Pat. No. 4,794,651, the disclosure of which is incorporated herein by reference, or are described in US Pat. It is a variation that is well known. For colored liquid developers, carbon black is replaced by color pigments, as is well known in the art. Other toners may be used instead, including liquid toners and, as indicated above, powdered toners.

  Another preferred embodiment of the toner for use in the present invention is prepared using the following method.

  1) Solubilization 1400 grams of Nucrel 925 (ethylene copolymer by Dupont and 1400 grams of Isopar L (Exxon) were prepared in an oil heated with a Ross Double Planetary Mixer at least 24 RPM for 1.5 hours. Is thoroughly mixed at a temperature of 130 ° C. 1200 grams of preheated Isopar L are added and mixing is continued for an additional hour. The mixture is cooled to 45 ° C. with stirring for several hours and the viscous material is added. To form

  2) Grinding / Pulverization The product of the 762 gram solubilization step is a JS attritor (Union Process Inc. Akron, OH) filled with 3/16 inch carbon steel balls at 250 RPM and 66.7 grams of Mogul. L carbon black (Cabot), 6.7 grams of BT 583D (blue pigment manufactured by Cookson), 5 grams of aluminum tristearate and an additional 1459.6 grams of Isopar L for 8 hours, 30 Crushed at ℃.

  3) Continue grinding 34.5 grams of ACumist A-12 (micronized polyethylene wax manufactured by Allied Signal) is added and grinding is continued for another 4 hours. The resulting particles are fibrous particles having a measured diameter in the range of 1-3 microns.

  The resulting material is diluted with additional Isopar L and Marcol 82 with a dry solids ratio of about 1.7% and an overall ratio of Isopar L to Marcol between about 50: 1 and 500: 1, and more. Preferably, the developer used will be between about 100: 1 and 200: 1. The charge director is added in an amount equal to 40 mg / gm solid, as described in US patent application Ser. No. 07 / 915,291 (utilizing lecithin, BBP, ICIG3300B) and WO 94/02887, and the particles of the toner. Charge. Other charge directors and additional additives may be used as known in the art.

  The process described above produces a black toner. Cyan, magenta and yellow toners are produced in step 2) using a mixture of different materials. For cyan toner, 822 grams of solubilized material, 21.33 grams of BT 583D and BT 788D pigment (Cookson), 1.73 grams of DI355DD pigment (BASF), 7.59 grams of aluminum, respectively. Tristearate, 1426 grams of Isopar L is used in step 2. For the magenta toner, step 2 uses 810 grams of solubilized material, 48.3 grams of Finess Red F2B, 6.81 grams of aluminum tristearate, and 1444.2 grams of Isopar L. Is For the yellow toner, 810 grams of solubilized material, 49.1 grams of D1355D pigment, 6.9 grams of aluminum tristearate, 1423 grams of Isopar L are used in Step 2.

  Intermediate transfer member 30 will be described in detail below, with particularly preferred embodiments thereof (along with FIGS. 3 and 4). U.S. Pat. No. 5,089,856 or 5,047,808, or any application in which this application is a continuation-in-part, incorporated herein by other structures known in the art. Any suitable intermediate transfer member having such a multilayer transfer member. Member 30 is maintained at a suitable voltage and temperature for electrostatic transfer of the image from the image bearing surface. The intermediate transfer member 30 is preferably associated with a pressure roller 71 for transferring an image to a final substrate 72 such as paper by heat and pressure. For the particularly preferred toner described above, an image temperature of about 95 ° C. at the onset of fusing is preferred.

  Certain aspects of the invention, particularly the method of placing the transfer blanket on the drum, are generally applicable and, as known in the art, apply to a wide range of types of blankets for ink, liquid toner, and powder toner. It is possible.

  The cleaning device 32 operates to scrub the surface of the photoreceptor 12 and preferably includes a cleaning roller 74, a sprayer 76 to assist in the process of spraying and scrubbing a non-polar cleaning solution, Includes a wiper blade 78 that completes cleaning of the photoconductive surface. A cleaning roller 74, made of any synthetic rubber known in the art for this purpose, is moved in the same direction as the drum 10, as indicated by arrow 80, causing the surface of the roller to rub the surface of the photoreceptor. To do. Any residual charge remaining on the surface of photoreceptor sheet 12 is removed by exposing the photoconductive surface to light from optional neutralizing lamp assembly 36, but this is not required in practice.

  According to a preferred embodiment of the present invention, after developing each image of a given color, a single color image is transferred to intermediate transfer member 30. Subsequent images of different colors are sequentially transferred to the intermediate transfer member 30 to match the previous image. When all desired images have been transferred, a complete multicolor image is transferred from transfer member 30 to substrate 72. Only the impression roller 71 creates a functional bond between the intermediate transfer member 30 and the substrate 72 when the transfer of the composite image to the substrate 72 takes place. In addition, each monochromatic image is separately transferred to the substrate via the intermediate transfer member. In this case, the substrate is fed once through the machine for each color, held on a platen, and contacts the intermediate transfer member 30 for composite image transfer. Alternatively, the intermediate transfer member is omitted, and the developed single-color image is directly transferred from the drum 10 to the base 72 sequentially.

  3A, 3B, 4A-4D illustrate a preferred embodiment of the intermediate transfer member 30 according to a preferred embodiment of the present invention. FIG. 3A shows the intermediate transfer blanket 100 installed on the drum 102. The transfer blanket 100 (details shown in FIGS. 4C and 4D) preferably includes a layered transfer member 104 and a mounting fixture 106.

  As best shown in FIG. 4C, transfer member 104 includes a release layer 109 that is outermost on the blanket when installed on drum 102. The underlying layer 109 is preferably made of a soft elastomer, preferably polyurethane, and is preferably about 65 or less, more preferably about 55 or less, but preferably about 35 or more Shore. The matching layer 111 has A hardness. A suitable hardness value is between 45 and 55, preferably about 50. The underlying layer 111 is a conductive layer 114 that covers the thin barrier layer 115. The barrier layer 115 covers the body 116 of the blanket and includes a top layer 118, a compression layer 120, and a fabric (woven) layer 122. Underneath the fabric layer is a layer 126 of adhesive, which is preferably in contact with the drum 102.

  Drum 102 is preferably heated by a heater, such as an internal halogen lamp heater, to facilitate transfer of the image from release layer 109 to the final substrate, as is well known in the art. Other heating methods, or no heating at all, are also used in practicing certain aspects of the invention. The degree of heating depends on the properties of the toner or ink used with the invention.

  As shown in FIGS. 4A, 4B, and 4D, the mounting fixture 106 comprises an elongated conductive bar 108 made of, for example, a metal such as aluminum (in the form of a finger-like extension). Take place) also conductive, preferably made of the same material as the bar 108, and preferably formed with a series of L-shaped mounting feet 110 formed integrally therewith. In particular, the bar 108 is formed with a groove into which the end of the layered transfer section 104 is inserted. Preferably, the end of the layered member inserted into the mounting bar does not have a release layer 109 or a matching layer 111, thereby exposing the conductive layer 114 and making electrical contact with the bar. Bars 108 are also formed with sharp internal protrusions that penetrate the outer layer of the blanket and contact the conductive layer.

  Optionally, each layer below conductive layer 114 is partially conductive (eg, by adding conductive carbon black or metal fibers) and the adhesive layer is conductive. This allows the current to flow directly from the surface of the drum to the conductive layer.

  In one preferred embodiment of the invention, the fixture 106 is formed from a single sheet of metal, the feet being bent into a U-shape to form a groove into which the layered member is inserted. Is partially cut from. After insertion, the outer wall of the groove is pressed against the layered member, securing the layered member to the groove. The partially cut member is bent to form a mounting foot.

  In the preferred embodiment of the present invention shown in FIGS. 1-3, the drum 102 is maintained at a potential, for example 500 volts, suitable for transferring an image to an intermediate transfer member, while the voltage is maintained at a mounting fixture. Applied to conductive layer 114 via 106. Therefore, the source of the transfer voltage is very close to the outer surface of the member 104, so that it is possible to lower the transfer potential of the drum.

  In the preferred embodiment of the present invention, the transfer unit 104 is manufactured by the following procedure.

  1. The first structure for the blanket structure is a blanket body 116 that is generally similar to that used for printing blankets. One suitable body is MCC-1129-02, manufactured and sold by Reeves SpA, Lodi Vecchio (Milan), Italy. Other suitable blanket types are U.S. Patent Nos. 5,047,808, 4,984,025, 5,335,054, WO 91/03007, WO 91/14393, WO 90/14619. No. WO 90/04216, which are incorporated herein by reference. In a preferred embodiment of the present invention, the body 116 is preferably a blend of a fabric layer 122 made of woven NOMEX material and having a thickness of about 200 microns, and preferably about 400 microns, of carbon black. The compression layer 120 is made of saturated nitrile rubber and has improved thermal conductivity. Layer 120 preferably includes small gaps (about 40-60% of the volume), and upper layer 118 is preferably made of the same material as the compression layer, but without gaps. Layer 109 is preferably about 100 microns thick. The blanket body is manufactured by a manufacturing method generally used for manufacturing an offset printing blanket for ink offset printing.

  The blanket body 116 is preferably dimensioned to a relatively precise thickness by abrading components on the surface of the upper layer 118. The preferred thickness for the finished body 116 is about 700 microns, but other thicknesses can be used depending on the dimensions of the printing system in which it is used and the exact material used for the blanket body.

  2. The side of the fabric of the blanket body 116 is preferably coated with a 30 micron thick layer of silicone-based adhesive (preferably Type D 66 manufactured by Dow Corning). The adhesive is H. P. Smith Inc. Covered with a sheet of mylar coated with a silicon fluoride material, such as DP 5648 release paper (one-sided coat), provided by Bedford Park, Illinois. This adhesive is characterized by good adhesion to the surface of the drum 102 and is resistant to the carrier liquid used for liquid toner. The blanket can be removed from the drum when its replacement is desired by cutting the blanket along the edge of the fixture 106 and removing the blanket and fixture.

  The adhesive is used to ensure good thermal contact between the back of the blanket and the drum on which it is installed. Silicone adhesive is used because the adhesive is typically used in a suitable apparatus attached to a blanket that is exposed to the heat generated in the underlying drum. The temperature of the drum varies depending on the thermal resistance of the blanket and the desired surface temperature of the blanket (which depends on the toner used in the process and the details of the transfer of the toner to the final substrate), but the temperature of the drum is 80 °. C., 100 C., 120 C., 150 C. or higher.

  3. The top layer 118 is preferably coated with a subbing sub-micron layer before being coated with additional layers. A preferred primer is Dow Corning 1205 Prime Coat. The type of undercoat depends on the properties of the upper layer and the conductive layer. Preferably, a 0.3 micron primer is applied to a wire rod coating apparatus no. 0 bar coats the clean top layer.

  4. The blanket body 116 may diffuse through the upper layer of the blanket as a gas, such as antioxidants, antiozonants, etc., when the blanket is heated during the imaging process, or when there is a carrier liquid such as Isopar L. Because of the additives, a barrier layer 115 is preferably coated over the top layer 118 (more precisely over the primer). This barrier layer is substantially impermeable to the diffusible material in the blanket body and to the carrier liquid used.

  If this layer is omitted, under certain conditions the added material may cause photoreceptor degradation. Specifically, it can be seen that the imaging process becomes dependent on humidity.

  In a preferred embodiment of the present invention, a layer of polyvinyl alcohol of 4-11 microns (88% hydrolyzed) is coated over the subbing layer overlying the top layer 118.

  Preferably, 88% hydrolyzed polyvinyl alcohol (Aldrich Chemical Co. Inc., Milwaukee, Wis.), Having an average molar weight between 85,000 and 145,000, is heated at 90 ° C. to a reflux system. Dissolve in water by stirring constantly for 30 minutes. After 30 minutes, an amount of ethanol equal to twice the amount of water is added to the solution, and the resulting concentration of polyvinyl alcohol is preferably less than 10%. Higher concentration solutions can be used, but are more difficult to spread evenly due to their higher viscosity.

  The solution is placed on the layer 118 of the body 116 using a thin wire rod or knife inclined 30-45 ° to the direction of knife or body movement. The solvent is dried at room temperature or evaporated by blowing hot air through the layers.

  Applying one or more coatings is utilized to obtain the required thickness.

  Too thin a layer results in transfer of the material from the body 116, which is correlated with reduced transfer efficiency from the photoreceptor to the intermediate transfer blanket, which may have been caused by photoreceptor degradation. A 4 micron material is sufficient to avoid leaching, but preferably a slightly larger thickness is used.

  Other barrier materials and other thicknesses may be used depending on the carrier liquid used in the toner and the gases generated by the body 116. Other barrier materials require less or greater thickness due to their resistance to carrier liquids and gases generated by body 116. Also, if the body 116 resists leaching by the carrier liquid and does not contain any material discharged (especially when the body 116 is heated) or any antioxidant or antiozonant, layer 115 is omitted.

  Polyvinyl alcohol is a thermoplastic crystalline material with a melting point above the temperature of the operating blanket. Polyvinyl alcohol is also believed to form a layer impermeable to the carrier of gases and hydrocarbons used in liquid toners.

  5. The conductive layer 114 is preferably formed of acrylic rubber to which conductive carbon black has been added. In the preferred embodiment of the present invention, only a few microns of conductive coating is required. The conductive layer is first mixed with 300 grams of Hytemp 4051EP (Zeon Chemicals) with 6 grams of Hytemp NPC 50 and 9 grams of sodium stearate in a 2 roll mill for 20 minutes, and then mixes 150 grams of the mixed material. It is formed by dissolving in 2000 grams of methyl ethyl ketone (MEK) and stirring at room temperature for 12 hours.

  Forty grams of conductive carbon black, such as, for example, Printex WE2 (Degussa), is added to the solution and the mixture is ground in a 01 attritor with the addition of 3/16 inch steel balls. Milling is carried out at 10 ° C. for 4 hours, after which time the material is diluted by adding MEK to 7.5-8% solids concentration and removed from the mill in the form of a conductive lacquer.

  The blanket is overcoated (after step 3 or step 4) with a conductive lacquer of about 3 microns (3 passes using a No. 0 rod) and dried at room temperature for 5 minutes.

  Before the conforming layer of soft elastomer is applied, an additional primer coat (except for the part inserted into the bar 108) is added over the conductive lacquer.

  The resistance of the conductive layer is preferably greater than about 20 kOhm / square, and preferably less than about 50 kOhm / square. This value depends on the resistivity of the layer above the conductive layer and the aspect ratio of the blanket. In general, the resistance is low enough that the current flowing through the conductive layer (to supply leakage current through the overlying layer) does not cause a substantial change in voltage along the surface of the blanket. Should. The resistance of the conductive layer and, more importantly, the overlying layer controls the current flowing through the overlying layer. Generally speaking, the conductive layer has a relatively low resistance and resistivity, the conforming layer (layer 111) has a higher resistivity, and the overlying release layer (layer 109) has a higher resistivity. Have.

  6.1 kg of pre-filtered Fomrez-50 polyester resin (Hagalil Company, Acidod, Israel) is dewatered and degassed at 60 ° C. in vacuo. 600 grams of degassed material is mixed with 1.4 grams of dibutyltin dilaurate (Aldrich) and degassed for 2 hours at room temperature. 30 grams of the finished material, 3.15 grams of RTV Silicon 118 (General Electric), 4.5 grams of polyurethane crosslinker DESMODUR 44V20 (Bayer) are stirred together. The material of the 100 micron layer is no. The three-wire rod is used to coat the primed conductive layer in several passes in clean conditions, preferably in class 100 conditions. The coating is cured for 2 hours at room temperature under a clean hood to form a layer of polyurethane.

  Other methods of forming a suitable conforming layer (matching layer) are shown and described in the parent application of the present application. Further, the conductive layer is omitted, and the layer 118 is made conductive.

The layer 111 thus formed has a resistance on the order of about 10 ⁹ Ω-cm and preferably has good thermal stability at the operating temperature of the blanket surface, which is about 100 ° C. or less.

  The function of the conforming layer is to provide a good fit of the blanket to the imaging surface (and of the image on the imaging surface) at the low pressures used during transfer of the image from the imaging surface to the blanket. is there. The layer should preferably have a Shore A hardness between 25 or 30 and 65, more preferably about 50. A thickness of 100 microns is preferred, but other thicknesses between 50 microns and 300 microns are also used, with 75-125 microns being preferred.

7. Preferably, 12 grams of RTV silicon 236 (Dow Corning) release material diluted with 2 grams of Isopar L (Exxon) and 0.72 grams of Syl-off 297 (Dow Corning) are mixed together. A wire rod (Bar No. 1) coating system is used, passing 5 to 6 times under clean conditions to achieve a release layer thickness of 8 microns. The material is cured at 140 ° C. for 2 hours. The cured release material has a resistivity of about 10 < ¹⁴ > to 10 < ¹⁵ > [Omega] -cm.

  To install the blanket 100 on the drum 102, the mounting feet 110 preferably include a plurality of installations formed on the drum 102 without removing the mylar sheet from the layer of adhesive (the back of the blanket). Is inserted into the hole 130. As can be seen most clearly in FIGS. 3A, 3B and 4D, the mounting feet 110 each have a tip portion 132 and a back portion 134. The tip 132 is inserted into a groove formed in the far side wall of the mounting hole 130 and the back portion 134 is located toward the side wall opposite the hole. In this way, the edges of the blanket are accurately positioned. The edge of the mylar sheet closest to the foot is removed, and the remaining mylar sheet is removed when the adhesive confirms that the subsequent portion of the blanket attached to the drum rests flat against the drum. Removed sequentially.

  The present inventor has discovered that this placement method is far superior in providing a stable transfer surface as compared to a placement method using only an adhesive or a gripper at both ends of the blanket.

  Alternatively or additionally, a very soft conforming layer on the back of the blanket can be used. This type of soft layer provides good thermal contact between the blanket and the heated drum 102 so that the temperature of the drum does not need to be too high to bring the outer surface of the blanket to operating temperature. In addition, such a very soft layer makes the blanket "stick" to the drum, thus eliminating the need to use an adhesive under certain conditions. Furthermore, when the blanket is changed, no adhesive remains on the drum to be removed.

  Very soft layers are produced in the following way.

  1. 100 g of Hi-Temp 4051 EP (Zeon) acrylic resin is mixed with 2 g of NPC-50 crosslinker (Zeon) and 3 g of sodium stearate, dissolved in toluene, and mixed with 15% non-volatile solid solution. I do. Optionally, up to about 40 g of carbon black Pearls 130 (Cabot) is added.

  2. A thin layer of the solution is coated on a mylar coated for release and dried. This process is repeated until a suitable thickness of 20-30 microns is achieved.

  3. The uncured resin is laminated (overlaid) to a layer of adhesive on a blanket made in accordance with the invention or directly to a layer of fabric. This step is preferably performed before curing of the release layer.

  4. The laminate structure is cured with the release layer and the release coated mylar is removed.

  This layer has a Shore A hardness of about 20-24 without carbon black and about 40-45 with carbon black. Softer materials (softer materials) are also suitable, but substantially harder materials do not adhere well to the drum surface. Optionally, the adhesive layer at the bottom of the blanket is not coated into a very soft layer, improving the bond between the blanket and the drum. This is particularly desirable for harder layers.

Acrylic materials can be replaced with other soft elastomeric materials such as soft polyurethane or nitrile rubber. Other heat modifying fillers, such as Fe ₂ O ₃ and alpha aluminum oxide, which have a smaller effect on the hardness of the final product, can also be used in place of carbon black.

  FIG. 5 shows another method of the preferred embodiment of the present invention in which somewhat differently shaped holes 130 'are used. In this embodiment, the back portion 134 rests against a protrusion 150 formed on one side of the hole, and the surface 154 of the foot 110 rests on the bottom 156 of the protrusion formed on the other side of the hole.

  The preferred electrical connection between the conductive layer and the mounting bar is to remove (or not form) the layer that preferably covers the edges of the conductive layer, for example, the overlying layer. For example, by crimping or penetrating the mounting bar at the point marked 160 in FIG. 4D. Crimping is also used to hold the blanket in the installation bar.

  The layer of adhesive preferably covers the back of the blanket, or the layer of adhesive covers only a portion of the back, such as the furthest edge of the blanket (blanket hem), or is present in the present invention. In embodiments, it is also omitted under certain conditions.

  Certain aspects of the present invention are not limited to the particular type of imaging system used, and certain aspects of the present invention may also include any suitable imaging system for forming an image of a liquid toner on an imaging surface, the present invention It will be appreciated that certain aspects are also beneficial in powder toner systems. Certain aspects of the invention are also useful in systems that use other types of intermediate transfer members, such as belts and continuous coated drum type transfer members. Certain aspects of the present invention are also suitable for use with an offset printing system. While the specific details given above for the imaging system include some of the best modes for carrying out the invention, many aspects of the invention relate to electrophotographic, offset printing, and copying techniques. It is applicable to a wide range of known systems.

  Those skilled in the art will understand that the present invention is not limited to the description and examples provided herein. Rather, the scope of the present invention is defined solely by the following claims.

1 is a simplified cross-sectional view of an electrostatic imaging device constructed and operative in accordance with a preferred embodiment of the present invention. FIG. 2 is a simplified enlarged sectional view of the device of FIG. 1. FIG. 4 is a simplified side cross-sectional view of an intermediate transfer member including a removable intermediate transfer blanket mounted on a drum, according to a preferred embodiment of the present invention. FIG. 3B is a partially cutaway plan view of the intermediate transfer member of FIG. 3A. FIG. 4 is a corresponding plan view of an intermediate transfer blanket according to a preferred embodiment of the present invention. FIG. 4 is a corresponding side view of an intermediate transfer blanket according to a preferred embodiment of the present invention. 3 shows details of the layered structure of the intermediate transfer blanket according to a preferred embodiment of the present invention. FIG. 4C is a cutaway enlarged view of a fixing mechanism of the intermediate transfer blanket of FIGS. 4A and 4B. FIG. 4 is a simplified cross-sectional view of a portion of an intermediate transfer member including a removable intermediate transfer blanket mounted on a drum, according to another preferred embodiment of the present invention.

Claims (27)

An imaging device,
An imaging surface having a formed toner image;
An intermediate transfer member, which receives the image of the toner from the imaging surface and from which the image is subsequently transferred, the intermediate transfer member comprising:
A drum with a recess for installation formed inside,
An intermediate transfer blanket mounted on the drum, wherein the blanket comprises:
A layered transfer portion having a transfer surface for receiving a toner image on one side;
A mounting fixture attached to only one edge of the layered transfer portion and adapted to be combined with the mounting recess of the drum;
A device that can be installed on a drum so that the transfer blanket can be removed.   2. The apparatus of claim 1, wherein at least a portion of the surface of the layered transfer portion opposite the transfer surface is adhered to the drum.   Apparatus according to claim 1 or claim 2, wherein the layered transfer portion comprises a layer of adhesive on a second side opposite the transfer side. The layered transfer portion includes a conductive layer under the transfer surface,
Apparatus according to any of the preceding claims, wherein the mounting fixture comprises a conductive element mounted on one edge of the transfer portion and in direct contact with the conductive layer.   5. The apparatus of claim 4, wherein the conductive element contacts the drum and the drum is charged to a voltage that operates to transfer the toner image from the imaging surface to the transfer surface.   5. The device of claim 4, wherein the conductive element includes at least one "L" -shaped finger extension extending therefrom.   A first portion, wherein the at least one "L" -shaped extension extends in a direction perpendicular to the layered transfer portion; and a layered transfer portion attached to and substantially perpendicular to the first portion. 7. The device of claim 6, having a second portion that is substantially parallel and extends away therefrom.   The apparatus of claim 7, wherein the mounting recess further comprises a recess for receiving the second portion. A substantially rectangular intermediate transfer blanket,
A layered transfer portion having a transfer surface on one side,
A mounting fixture adapted to mount the blanket on the drum, the mounting fixture attached to only one edge of the layered transfer portion. The layered transfer portion includes a conductive layer under the transfer surface,
10. The intermediate transfer blanket of claim 9, wherein the mounting fixture includes a conductive element attached to one edge of the transfer portion and electrically connected to the conductive layer.   The intermediate transfer blanket of claim 10, wherein the conductive element includes at least one "L" -shaped finger extension extending therefrom.   A first portion extending in a direction perpendicular to the layered transfer portion, the at least one "L" shaped extension; and a layered transfer portion attached to and substantially perpendicular to the first portion. The intermediate transfer blanket of claim 11, having a second portion that is substantially parallel and extends away therefrom.    A resilient layer underlying the transfer surface, and a barrier layer substantially impermeable to liquid hydrocarbons and positioned between the resilient layer and the transfer surface. An intermediate transfer blanket according to any one of claims 9 to 12.   Claims: comprising a resilient layer underlying the transfer surface, and a barrier layer substantially impermeable to gas and positioned between the resilient layer and the transfer surface. Item 13. The intermediate transfer blanket according to any one of items 9 to 12.   An intermediate transfer blanket according to any of claims 9 to 14, wherein the layered transfer portion comprises a conformable layer made of a material having a Shore A hardness of less than 65.   16. The intermediate transfer blanket of claim 15, wherein the material of the conformable layer has a Shore A hardness of less than about 50.   17. The intermediate transfer blanket of claim 15 or 16, wherein the material of the conformable layer has a Shore A hardness of greater than about 30.   18. A method according to any one of claims 9 to 17, wherein the layered transfer portion comprises a soft layer on the surface of the layered transfer portion, opposite the transfer surface, having a Shore A hardness of less than 90. Intermediate transfer blanket.   19. The intermediate transfer blanket of claim 18, wherein the soft layer has a Shore A hardness of less than about 45.   19. The intermediate transfer blanket of claim 18, wherein the soft layer has a Shore A hardness of less than about 25.   19. The intermediate transfer blanket of claim 18, wherein the soft layer has a Shore A hardness of about 45.   22. An intermediate transfer blanket according to any one of claims 9 to 21, wherein the layered transfer portion comprises a layer of adhesive on a surface opposite the transfer surface.   23. The intermediate transfer blanket of claim 22, wherein the layer of adhesive is stable at a temperature of at least 80C.   24. The intermediate transfer blanket according to claim 22 or claim 23, wherein the layer of adhesive is stable at temperatures above 100C.   25. The intermediate transfer blanket of claim 24, wherein the layer of adhesive is stable at temperatures above 150C.    The intermediate transfer blanket according to any one of claims 9 to 25, wherein the outer layer is a toner release layer. An imaging apparatus for performing an imaging process,
An imaging surface formed thereon, having an image of a liquid toner consisting of toner particles and a carrier liquid,
27. An intermediate transfer blanket according to any one of claims 9 to 26, wherein the intermediate transfer blanket receives an image of toner from an imaging surface, from which the image is subsequently transferred.

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