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
  • G03G15/65—Apparatus which relate to the handling of copy material
  • G03G15/6597—Apparatus which relate to the handling of copy material the imaging being conformed directly on the copy material, e.g. using photosensitive copy material, dielectric copy material for electrostatic printing
• • 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
  • G03G15/75—Details relating to xerographic drum, band or plate, e.g. replacing, testing
  • G03G15/751—Details relating to xerographic drum, band or plate, e.g. replacing, testing relating to drum
  • G03G15/752—Details relating to xerographic drum, band or plate, e.g. replacing, testing relating to drum with renewable photoconductive layer
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/10—Bases for charge-receiving or other layers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/10—Bases for charge-receiving or other layers
  • G03G5/101—Paper bases
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/10—Bases for charge-receiving or other layers
  • G03G5/102—Bases for charge-receiving or other layers consisting of or comprising metals
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/10—Bases for charge-receiving or other layers
  • G03G5/105—Bases for charge-receiving or other layers comprising electroconductive macromolecular compounds
  • G03G5/108—Bases for charge-receiving or other layers comprising electroconductive macromolecular compounds the electroconductive macromolecular compounds being anionic

Definitions

• the present invention relates to image forming and image transfer apparatus especially for use in electrostatic imaging using a sheet type photoreceptor.
• Organic photoreceptor materials for use in toner imaging are well known.
• the organic photoreceptor is coated onto a drum or endless belt on which an electrostatic image is formed.
• a sheet of photoreceptor material is mounted onto a drum to provide the same function.
• the present invention seeks to provide, in a first aspect thereof, improved image forming apparatus utilizing a new sheet photoreceptor configuration.
• imaging apparatus including: a substantially rectangular organic photoreceptor sheet including a backing layer, a conductive layer and a photoconductive layer, wherein along one edge of the sheet there is an exposed conductive area, preferably an exposed portion of the conductive layer; a drum having a longitudinal cavity formed therein and including a slot formed between the cavity and the cylindrical surface of the drum into which the one edge of the photoreceptor sheet is inserted; and a rotatable element within the cavity which, in a locking position, presses the sheet, and preferably the conductive area thereof against a wall of the cavity, fixedly and removably holding the photoreceptor sheet in place.
• the conductive area is pressed against the rotatable element.
• the drum is at substantially ground electrical potential .
• both the photoconductive and conductive layers are not present and wherein the portion of the photoreceptor sheet overlies the slot .
• the chargeable photoreceptor includes a dust masking layer, preferably of paper, between the backing layer and the drum .
• the dust absorbing is attached to the backing layer only along an edge of the paper layer, preferably adj acent to the slot .
• a substantially rectangular organic photoreceptor sheet including a backing layer , a conductive layer and a photoconductive layer wherein along one edge thereof the photoconductive layer is not present such that the conductive layer is exposed .
• a substantially rectangular organic photoreceptor sheet including a backing layer , a conductive layer and a photoconductive layer wherein along one edge thereo f there is an exposed conductive area.
• both the photoconductive and conductive layers are not present.
• the photoreceptor sheet includes a dust masking layer , preferably of paper , proximate the backing layer .
• the dust absorbing is attached to the backing layer only along an edge of the dust absorbing layer, preferably adjacent to exposed conductive edge.
• a substantially rectangular organic photoreceptor sheet including a backing layer , a conductive layer and a photoconductive layer wherein along one edge thereof the photoconductive layer and the conductive layers are not present .
• the photoreceptor sheet includes a dust masking layer , preferably of paper, proximate the backing layer .
• the dust absorbing is attached to the backing layer only along an edge of the dust absorbing layer .
• the dust masking layer i s attached adjacent to and displaced from an edge of the photoreceptor opposite the one edge thereof at which the photoconductive layer and the conductive layers are not present .
• a substantially rectangular organic photoreceptor sheet including a backing layer, a conductive layer and a photoconductive layer and further including a dust masking layer, preferably a paper layer, proximate the backing layer.
• the dust masking layer is attached to the backing layer only along an edge of the dust masking layer, preferably , adj acent to and displaced from an edge of the photoreceptor.
• a substantially rectangular organic photoreceptor sheet including a backing layer, a conductive layer and a photoconductive layer, wherein an edge of the backing layer extends beyond an edge of the photoconductive layer and beyond an edge of the conductive layer and wherein the edge of the conductive layer is coated with a layer of substantially insulating material .
• the insulating material preferably includes a dielectric material .
• the insulating material includes HumiSeal type 1A24.
• the respective edges of the photoconductive layer and the conductive layer are substantially aligned .
• the edge of the conductive layer extends slightly beyond the respective edge of the photoconductive layer.
• FIGS. 1A and IB are cross-sectional, simplified, overall and expanded, partial drawings, respectively of a drum on which a photoreceptor is mounted, showing a mounting method for photoreceptors in accordance with a preferred embodiment of the invention
• Figs. 1C and ID show an alternative method for mounting photoreceptors in respective open and gripping configurations
• Fig. 2A and 2B are respective top and side views of a photoreceptor in accordance with a preferred embodiment of the invention
• Figs . 2C and 2D are cross-sectional partial side views of the photoreceptor of Figs . 2A and 2B; Fig .
• FIG. 2E is a cross-sectional partial side view of a photoreceptor in accordance with another , pre ferred , embodiment of the present invention
• Fig . 3A and 3B are cross-sectional partial side views of two, respective, types of insulated-edge photoreceptors, constructed in accordance with a further pre ferred embodiment of the present invention
• Figs . 4A, 4B, and 4C are respective side view, top view , and side view illustrations of three , respective , steps in a preferred method of forming the insulated edge photoreceptor of Fig. 3A.
• FIG. 1A - ID and 2A - 2D A novel photoreceptor sheet 12 and apparatus and a method for mounting the sheet on a drum 10 are shown in Figs. 1A - ID and 2A - 2D.
• Photoreceptor sheet 12 is preferably mounted on drum 10 using the mechanisms shown in Figs. 1A and IB or 1C and ID. As shown most clearly in Fig. IB, one end of photoconductive sheet is inserted into a slot 140 which forms the entryway to a cavity 142 formed in drum 10. An eccentric cylindrical 1 cam 144 which is situated in the cavity can be rotated to
• the photoreceptor can be any photoreceptor 3 shown by dotted lines in Fig. IB, the photoreceptor can be
• cam 144 is rotated to the position shown by the
• FIGS. 1C and ID show a rotating member 20 having a
• the photoreceptor can be inserted into slot 140
• resilient element 22 is
• Photoreceptor sheet 12 consists essentially of an
• 29 photoreceptor sheet 12 comprises four layers, a paper layer
• a backing layer 152 such as of Mylar
• the photoconductive layer comprises a
• a photoconductive layer for simplicity of the discussion, since the exact construction of the photoconductive layer or layers does not form a part of the present invention.
• a preferred photoreceptor is, for example, Emerald 2 (manufactured by Lexmark) .
• the photoconductor should preferably be treated by one of the treatments specified in PCT publication WO 91/17485 which corresponds to copending U.S. Application 07/946,411, the disclosure of which is incorporated by reference. In general these applications describe several processes. In one process, the photoreceptor sheet is mounted on a drum with the photoconductive surface facing outwards.
• the sheet is subjected to heat treatment which removes stress from the photoconductive layer without removing it from the backing layer.
• the photoreceptor is now cooled, without removing it from the drum.
• the photoconductive layer is in compression and the backing layer is in tension.
• the photoreceptor sheet is subjected to tension and heated to a temperature at which the photoconductive layer is stress released but at which the backing is not stress released.
• the sheet is cooled and then the tension is removed. This process also results in a photoreceptor sheet in which the photoconductive layer is in compression and the backing layer is in tension.
• the surface of the photoconductive layer is chemically treated to remove stress from the layer and make it more plastic or elastic than it previously was.
• Figs. IB-ID Preferably materials such as cyclohexanone are used to chemically treat the photoconductive layer.
• the end of the sheet which is inserted into slot 140 has only two layers, i.e. , backing layer 152 and conducting layer 154. This assures that the conducting layer, when pressed against the interior of cavity 140 by cam 144 or member 22, will make good electrical contact with the cavity wall. This provides convenient grounding of the conductive layer, even when the backing layer and the paper layer are not conducting.
• the photoreceptor can be provided with a conductive edge which is electrically connected with the conductive layer and either the cavity wall or resilient member 22, or both.
• the paper layer as indicated above, is not attached to the back of the backing layer over the length of the photoreceptor. However, in a preferred embodiment of the invention, the paper is attached to the backing layer near the leading edge of the photoreceptor and at the end of the paper, i.e., at reference numeral 158.
• the function of the paper layer is to reduce the effect of dust or other particles which may be on the drum (or possibly between the photoreceptor and the paper) from effecting the imaging process by causing pressure points on the surface of the photoreceptor.
• the other end of the photoreceptor (its trailing edge), which is shown in detail in Fig. 2D preferably comprises only the backing layer, and, as shown in Figs. IB -ID, the backing layer extension is long enough to overlay slot 140 so as to avoid liquid toner entering cavity 142.
• the outer surface of drum 10 is shaped near slot 140 (at reference numeral 160) to provide a slope so that the contact between the photoreceptor and surfaces which it contacts is smooth, i.e., such that the overall diameter of the drum and the photoreceptor and, if present, the overlaying trailing edge, remains independent of the angular position on the drum. All the layers other than the backing layer are removed at the trailing edge mainly to obviate any chance that the conducting surface will touch a charging device such as a scorotron which is normally present in electrostatic imaging apparatus.
• a charging device such as a scorotron which is normally present in electrostatic imaging apparatus.
• the generally dielectric backing layer 152 remains substantially constantly charged, at the trailing edge, when the photoreceptor sheet is in operative use. This results in electrostatic attraction between drum 10 and the charged trailing edge of sheet 12, assisting in the adherence of sheet 12 to drum 10. It should be noted that sheet 12 is generally not attached to drum 10 by mechanical means, other than at the leading edge, to account for possible variations in the length of sheet 12 during operation. The electrostatic force provided by the dielectric trailing edge of sheet 12 allows circumferential relative motion between sheet 12 and drum 10.
• the trailing edge of the photoreceptor is cut at a slight angle to square, of about 1 in 35. This angle is used to provide a smooth transition of contact, at the edge, for a cleaner blade, used to clean untransferred toner from the photoreceptor, prior to the next imaging cycle.
• a photoreceptor sheet having square cut ends or having one or both edges cut at a slight angle is referred to herein as a "substantially rectangular" photoreceptor sheet. All edges and transitions are preferably smooth without jagged margins. For clarity, the overlapping end of the photoreceptor sheet is not shown in Figs. 1C and ID.
• leading and trailing edges of the photoreceptor can be varied to suit the particular application.
• the present inventors have found that the leading, conductive edge (inserted into slot 140) of the photoreceptor is preferably about 13 mm wide and the trailing edge (for overlap) is preferably about 20 mm wide.
• the direction of rotation of drum 10 is shown by an arrow 162.
• Fig. 2D Unfortunately, these desired arrangements of the trailing edges have been found to be extremely difficult to implement.
• FIG. 2E illustrates an alternative, more practical, embodiment of the trailing edge of photoreceptor sheet 12 in which conductive layer 154 extends slightly beyond photoreceptor layer 156.
• the above described photoreceptor sheet 12 may be used in any known electrostatic imaging device.
• liquid toner imaging apparatus is used, preferably of the type described in U.S. Patent application 08/371117, filed January 11, 1995, the disclosure of which is incorporated herein by reference.
• an electrically biased squeegee roller (not shown) is used for squeegeeing a layer of liquid toner which is developed onto the photoreceptor surface.
• the squeegee roller is typically electrically biased, preferably to a negative voltage of 1300-1600 Volts, and urged against the photoreceptor with a predetermined pressure, typically approximately 90 grams per centimeter along the length of the squeegee roller.
• a predetermined pressure typically approximately 90 grams per centimeter along the length of the squeegee roller.
• This breakdown of voltage may occur during actual contact between the squeegee roller and the trailing edge of layer 154 or by arcing between the squeegee roller and the conductive layer. Actual contact between the edge of layer 154 and the squeegee roller is possible, particularly in the embodiment of Fig. 2E, due to slight compliance of the generally resilient sheet 12 when urged by the generally rigid squeegee roller. It is appreciated that the above described breakdown results in gradual , accumulative, deterioration of both photoreceptor surface 12 and the squeegee rol ler .
• the trailing edge of layer 154 is insulated to prevent breakdown, as described in detai l below . I t should be noted that insulation of the trailing edge of layer 154 is preferred also in the desired , yet not readi ly implemented , arrangement (not shown in the drawings ) in which the trailing edge of layer 156 extends beyond the trailing edge of layer 154. Figs.
• FIG. 3A and 3B which schematically illustrate two types of trailing edges, analogous to the two types of trailing edges shown in Figs. 2D and 2E, respectively, whose conductive layers 154 are electrically insulated at edges 170 and 172, respectively, in accordance with a preferred embodiment of the present invention.
• a layer 175 of, preferably dielectric, insulating material is applied to trailing edge 170 (Fig. 3A) or trailing edge 172 (Fig. 3B), preventing electrical breakdown thereat.
• layer 175 preferably extends slightly beyond edges 170 or 172, both on photoreceptor layer 156 and on backing layer 152.
• extension 176 is preferably made extremely thin to avoid damage to the scraper. This is because the scrapers used by such imaging systems are generally extremely sensitive to protrusions in the direction of scraping.
• insulating layer 175 is formed of HumiSeal type 1A24, a vinyl-modified- epoxy based dielectric material, available from Columbia Chase Corporation, New York, USA.
• This insulating material is provided in a solids concentration of 20-24 percent by weight and a viscosity of 100-130 centipoise and has a drying/handling time of 15 minutes and a recommended curing time of 24 hours in room temperature.
• the material can be thinned, for example using acetone, to adjust the viscosity of the material for a given method of application.
• the cured layer is generally transparent, highly adhesive, very flexible and very durable to varying temperature and humidity conditions.
• the cured layer has a dielectric withstand voltage of approximately 3,900 Volts, a dielectric constant of approximately 2.88 at 1MHz and 25 degrees centigrade, a dissipation factor of 0.002, an insulation resistance of approximately 350,000,000 Megohms and a moisture resistance of approximately 30,000 Megohms.
• the material is also highly resistant to solvents and various chemicals.
• layer 175 may be formed of any other suitable dielectric material.
• layer 175 may be formed of HumiSeal type 1A33, a polyurethane based dielectric material, or the layer may be formed of a material based on polyvinyl alcohol (88% hydrolyzed), as described in copending U.S.
• FIG. 4A-4C schematically illustrate a preferred method of applying layer 175 to edge 170, by metered brushing. It should be appreciated that the same application method can be used for applying layer 175 to edge 172 if sheet 12 is constructed as in Fig. 2E. Although the method of Figs. 4A-4C has been found effective, it should be appreciated that other application methods, such as spraying or dipping, may also suitable.
• Fig. 4A illustrates a first step in the metered application method, in which a series of drops 178 of the insulating material are guided along the surface of an 1 application blade 177 to a portion of backing layer 152
• Drops 178 are preferably
• Fig. 4C illustrates a preferred brushing technique
• Brushing sheet 180 may be formed of any suitable rubber or
• brushing sheet 180 is formed of the material used for the

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Discharging, Photosensitive Material Shape In Electrophotography (AREA)

Applications Claiming Priority (5)

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• 1995
  • 1995-06-06 DE DE69535470T patent/DE69535470T2/de not_active Expired - Lifetime
  • 1995-06-06 CA CA 2199374 patent/CA2199374A1/en not_active Abandoned
  • 1995-06-06 JP JP50938896A patent/JP4101288B2/ja not_active Expired - Lifetime
  • 1995-06-06 EP EP95920303A patent/EP0779997B1/de not_active Expired - Lifetime
  • 1995-06-06 WO PCT/NL1995/000201 patent/WO1996007955A1/en active IP Right Grant
  • 1995-06-06 AU AU25797/95A patent/AU2579795A/en not_active Abandoned

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