Electro-photography printing devices including photoreceptors for creating a latent image that may be subsequently developed and printed are known in the art. Typically, the photoreceptor is made up of a thin photoreceptor sheet attached to a rotatable drum. Typically, the photoreceptor sheet is periodically replaced due to damage. During operation, a charger uniformly charges the photoreceptor. The drum is rotated and a laser writer discharges the photoreceptor in selected areas to create a latent image. Continued rotation of the drum brings the selectively charged photoreceptor into contact engagement with a developer roller for developing the latent image. The developed latent image is then transferred to a desired substrate. Alternatively, there may be provided an intermediate transfer member, which may be a drum or belt and which is in operative engagement with the photoreceptor bearing the developed image
One system is described in U.S. Pat. No. 5,508,790 to Belinkov et al. entitled “Photoreceptor Sheet and Imaging System Utilizing Same” which is incorporated herein by reference.
The subject matter regarded is particularly and distinctly claimed in the concluding portion of the specification. Non-limiting examples of embodiments of the present invention are described below with reference to figures attached hereto, which are listed following this paragraph. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same symbol in all the figures in which they appear. Dimensions of components and features shown in the figures are chosen for convenience and clarity of presentation and are not necessarily shown to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
In the following description, exemplary, non-limiting embodiments of the invention incorporating various aspects of the present invention are described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details presented herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the present invention. Features shown in one embodiment may be combined with features shown in other embodiments. Such features are not repeated for clarity of presentation. Furthermore, some unessential features are described in some embodiments.
In the design of a faster printer, the present inventors have found that the lifespan of the photoreceptor sheet has been further limited. It has been found that faster printing increases the stresses on the photoreceptor and periodically leads to disengagement of the photoreceptor from the drum and/or mechanical damage to the thin photoreceptor sheet. This reduces its lifetime.
An aspect of some embodiments of the invention is the provision of an improved device for holding a thin photoreceptor sheet onto a drum of an electro-photography printing device.
According to some embodiments of the present invention, the improved device includes a holding surface engaging the sheet by moving toward the sheet in a substantially perpendicular direction to the surface of the sheet. Force is transmitted to the sheet over a surface area engaged with the holding surface facilitating substantially uniform holding pressure over that area. The holding surface is an improvement over existing devices that engage the sheet by rotating an element that is substantially tapered and/or a leaf spring that engages the sheet over a line. The tapered end of the rotating element presses the sheet against a wall, transmitting force to the sheet over a line and/or over a minimal area. Providing a holding surface that engages the sheet in a substantially perpendicular direction as is provided in embodiments of the present invention, increases the holding robustness of the device and reduces stresses imposed on the sheet that can lead to damage of the sheet.
According to some embodiments of the present invention, the holding surface is an end surface of a clamping element that slides along a channel. In some exemplary embodiments, the clamping element rests on a rotatable shaft that is operative to translate the clamping element responsive to a rotation of the shaft. In some exemplary embodiments, the shaft engages the clamping element on a surface opposite that of the holding surface.
According to some embodiments of the present invention, a second clamping element engages the sheet from an opposite direction. In some exemplary embodiments, the second clamping element is preloaded by a spring. The preload spring can be positioned in a number of locations with respect to the second clamping element. In some exemplary embodiments, the spring is a wave spring having a length substantially corresponding to a length of the sheet. In some exemplary embodiments, the preload force of the spring is adjustable. In some exemplary embodiments adjustment to the preload force is facilitated with a slider and an associated set screw operative to press against the spring.
According to some embodiments of the present invention, the improved device includes a substantially rigid holding surface backed by a pre-loaded spring. The holding surface engages the sheet by moving toward the sheet in a substantially perpendicular direction to the surface of the sheet and engages the sheet over a substantially flat surface. As is described herein above, force is transmitted to the sheet over the surface area of the holding surface facilitating substantially uniform holding pressure over the surface area of the sheet engaged with the holding surface.
An aspect of some embodiments of the present invention is the provision of an improved device for removably holding a thin photoreceptor sheet onto a drum of an electro-photography printing device. According to some embodiments of the present invention the device includes a handle that can, by rotation, effect engagement and/or disengagement of the photoreceptor sheet from the drum. In some exemplary embodiments, the handle is fixed to the rotating shaft described above.
According to some embodiments of the present invention, the device includes a mechanism handle for engagement and/or disengagement of the photoreceptor sheet from the drum. In some exemplary embodiments, at least one part of the mechanism handle is fixed to the shaft while other parts are attached to drum. According to some embodiments of the present invention, the mechanism handle eases operation of the device for holding the thin photoreceptor sheet onto the drum, e.g. reduces the force employed for operating the device.
An exemplary embodiment of the present invention provides a device for holding a photoreceptor sheet onto a drum of an electro-photography printing device comprising first and second holding surfaces that are configured to hold an edge of the photoreceptor sheet from opposite directions by pressing against the sheet in a substantially perpendicular direction with respect to the surface of the sheet, wherein at least the second holding surface is pre-loaded.
In some embodiments, the first and the second holding surfaces are surfaces of a corresponding first and second clamping element.
In some embodiments, at least the first clamping element rests on a rotatable shaft.
In some embodiments, the first clamping element approaches and recedes from the second holding surface in response to rotation of the shaft.
In some embodiments, the shaft has a cross sectional shape that includes a circular portion and a flat portion.
In some embodiments, the first clamping element recedes from the second clamping element in response to the first clamping element resting on the flat portion of the shaft.
In some embodiments, at least one of the first or the second holding surface is pre-loaded by a spring.
In some embodiments, the spring is a wave spring.
In some embodiments, the length of the spring corresponds to at least the length of the edge of the photoreceptor sheet.
In some embodiments, the spring is a leaf spring.
In some embodiments, the spring rests on the second clamping element on a surface opposite the holding surface of the second clamping element.
In some embodiments, the device comprises a sliding element at least partially resting on the spring and a set screw configured to translate the sliding element over the spring.
In some embodiments, the sliding element and the set screw are configured for adjusting the pre-load of the spring.
In some embodiments, the drum includes a slot on the perimeter of the drum and wherein the device is positioned on the drum proximal to the slot so that the slot forms an entryway into the device.
In some embodiments, the device comprises a handle fixed to the rotatable shaft, wherein the handle is operative to hold and release the photoreceptor sheet from the drum.
In some embodiments, the photoreceptor sheet is a foil.
In some embodiments, the photoreceptor sheet has a thickness between 0.07 and 0.11 mm.
In some embodiments, the device applies a holding force at least 250 Kg on the photoreceptor sheet.
In some embodiments, the device applies a holding pressure of at least 70 MPa.
In some embodiments, the device is configured for removably fixing the photoreceptor sheet onto the drum.
In some embodiments, the device is configured for providing an electrical path between the photoreceptor sheet and the drum.
An exemplary embodiment of the present invention provides a device for holding a photoreceptor sheet onto a drum of an electro-photography printing device, the device comprising first and second holding surfaces that are configured to clamp an edge of the photoreceptor sheet from opposite directions by pressing against the sheet in a substantially perpendicular direction with respect to the surface of the sheet, and a handle associated with the holding device, wherein the handle is operative to hold and release the photoreceptor sheet from the drum.
In some embodiments, at least one of the first or the second holding surfaces is pre-loaded by a wave spring.
In some embodiments, the device applies a holding force at least 250 Kg on the photoreceptor sheet.
In some embodiments, the device is configured for providing an electrical path between the photoreceptor sheet and the drum.
According to some embodiments of the present invention, a holding mechanism is integrated onto a photoreceptor drum of an electro-photography printing device and implemented to removably lock a photoreceptor sheet onto the photoreceptor drum. Reference is now made to
According to some embodiments of the present invention, holding device 150 includes a slider 240 that is configured to adjust the pre-loading force in spring 250. In some exemplary embodiments, a set screw 310 pushes slider 240 so as to push down on spring 250 and thereby increase the pre-load force. Releasing the force on slider 240 with set screw 310 reduces the pre-loading in spring 250. According to some embodiments of the present invention, a return spring 115 may be included to separate clamping element 110 and 120.
According to some embodiments of the present invention, while the holder is in open position, there is a gap between sliders 120 and 110, which allow the photoreceptor sheet to enter between them. According to some embodiments of the present invention, during an open state, return spring 115 may separate clamping element 110 and 120. In this position, the return spring separates the clamping elements so that the photoreceptor sheet 105 may be inserted between the clamping elements. According to some embodiments of the present invention, during an open state, set screw 310 is adjusted to push slider 240 so as to push down on spring 250 and thereby set the desired the pre-load force. In one exemplary embodiment, set screw 310 is adjusted so that the tip and/or tapered portion of push slider 240 slides until touching a wall of extrusion 133.
According to embodiments of the present invention, during the open position, the photoreceptor sheet 105 may be inserted through volume and/or cavity 130 between the clamping elements 110 and 120 and up until a wall of extrusion 133.
During initiation of a locking state of holding device 150, shaft 210 is rotated clockwise and, in response to the rotation, clamping element 110 approaches clamping element 120 in a substantially perpendicular direction with respect to the end surfaces of clamping element 110 and clamping element 120. As clamping element 110 approaches clamping element 120, clamping element 110 presses against clamping element 120 which is typically pre-loaded by a spring 250. During a locking state of holding device 150, clamping element 110 and clamping element 120 presses against the edge of the photoreceptor sheet which is inserted between them. According to some embodiments of the present invention, during initiation of a release state of holding device 150, shaft 120 is rotated counter clockwise again and in response to this rotation, clamping element 110 recedes from clamping element 120 in a substantially perpendicular direction with respect to the end surfaces of clamping element 110 and clamping element 120 the gap between them is created and releases the hold on the photoreceptor sheet. Since the clamping elements do not traverse the surface of the photoreceptor sheet, the force that can be applied is not limited as it is in the prior art by stresses in the photoreceptor sheet caused by such sliding.
In some exemplary embodiments, clamping element 110 is configured to rest on shaft 210 with a surface opposite to the surface engaging the photoreceptor sheet. Typically, spring 250 is positioned over clamping element 120 on a surface opposite the surface of clamping element 120 that engages the photoreceptor sheet. In some embodiments of the invention, rotatable shaft 210 has a substantially cylindrical circular cross section with a section sliced off, as shown in
The present inventors have found that the clamping element structure of holding device 150 facilitates higher and more uniform pressure on the sheet as compared to prior art devices.
In some exemplary embodiments, clamping element 120 is pre-loaded by spring 250. Pre-loading the clamping element with a spring increases the grip on the photoreceptor sheet and improves the uniformity of the force distribution over the edge of the sheet that is engaged by the holding device. In some exemplary embodiments of the present invention, spring 250 is a wave spring that extends over the length of the holding device. In one exemplary embodiment, spring 250 may comprise a leaf spring that extends over the length of holding device. In another exemplary embodiment, spring 250 comprises a series of springs positioned over the length of the holding device.
According to some embodiments of the present invention, the pre-load adjustment mechanism including set screw 310 and slider 240 facilitates pre-loading the wave spring 250 after assembly of clamping elements 110 and 120 and slider 240 inside the extrusion 133. In some exemplary embodiments, the assembly of the elements of the holding device, e.g. clamping elements 110 and 120 and slider 240, absent of the pre-load force provides for easier assembly.
According to some embodiments of the present invention, holding device 150 can apply a holding force of approximately 250 Kg and/or 70 MPa, although lesser or greater force can be used depending on the stress to which the photoreceptor sheet is subjected during printing.
Typically clamping elements 110 and 120 are rigid elements with flat surfaces. Optionally, clamping elements 110 and 120 may include ridges and/or protrusions etched and/or in some way formed onto a surface of the clamping elements, e.g. a surface of the clamping elements engaging the sheet, so that the ridges are forced into the sheet and hold it more securely. In some exemplary embodiments, clamping elements 110 and 120 may be coated, e.g. coated with a material to improve hold on the photoreceptor sheet, for example by increasing friction with the sheet.
According to some embodiments of the present invention, shaft 210 and a surface of the slider 110 resting on the shaft are coated with a material to minimize friction during rotation of shaft. In some exemplary embodiments, shaft 210 and the bottom surface of clamping element 110 are coated with chrome and/or nickel.
Reference is now made to
Reference is now made to
To mount photoreceptor sheet 105 onto the drum, one end of the sheet is inserted into slot 155 and thus into cavity 130 so that sheet 105 is positioned between clamping element 110 and clamping element 120 at the end of cavity 130.
According to some embodiments of the present invention, the outer surface of drum 100 as well as extrusions 133 and 136 are shaped near slot 155 to provide a slope so that the insertion of the photoreceptor sheet is facilitated. Further, in some exemplary embodiments, the other end of the photoreceptor sheet extends long enough to overlay slot 155 so as to avoid liquid toner entering cavity 130. According to some embodiments of the present invention, the photoreceptor sheet is a foil, e.g. a thin foil. In some exemplary embodiments, the sheet thickness ranges between 0.07 and 0.11 mm, e.g. 0.078-0.079 mm, approximately 0.08 mm, approximately 0.09 mm and/or 0.093 mm.
According to some embodiments of the present invention, the holding device provides improved ability to clean residual material from the photoreceptor sheet that may get stuck inside the holding device. For example, the holding device can be easily assembled and disassembled from the drum by two or more screws 169 on flange 167 for cleaning. In some exemplary embodiments, once the holding device is disassembled an air pressure gun pointed to cavity 130 may be used to remove residuals that may get stuck inside the holding device. In some exemplary embodiments, the holding device may be disassembled and cleansed, e.g. the sliders, wave spring and shaft may be disassembled for cleaning. Typically, cleaning of the holding device may be performed on site, e.g. the cleaning may take approximately 10 minutes to an hour during which the printer cannot print. This is an improvement over previously known holding devices where the disassembly of the holding device is more difficult and cleansing of the holding device is typically performed in the lab and not on site. During this time, the printer cannot be used.
Reference is now made to
In the closed position, photoreceptor 105 is clamped and fixed onto drum 100. One or more stoppers may be provided to limit the rotation of handle 410 between the open and closed state of the handle. A mechanism to lock the handle in a closed position may be included. The position of handle 410 as shown in
Reference is now made to
It should be further understood that the individual features described hereinabove can be combined in all possible combinations and sub-combinations to produce exemplary embodiments of the invention. Furthermore, not all elements described for each embodiment are essential. In many cases such elements are described so as to describe a best more for carrying out the invention or to form a logical bridge between the essential elements. The examples given above are exemplary in nature and are not intended to limit the scope of the invention which is defined solely by the following claims.
The terms “include”, “comprise” and “have” and their conjugates as used herein mean “including but not necessarily limited to”.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2007/082224 | 10/23/2007 | WO | 00 | 4/28/2010 |
Publishing Document | Publishing Date | Country | Kind |
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WO2009/054846 | 4/30/2009 | WO | A |
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Number | Date | Country | |
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20110182622 A1 | Jul 2011 | US |