US3813161A

US3813161A - Platen cover

Info

Publication number: US3813161A
Application number: US00340156A
Authority: US
Inventors: D Curtis
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1973-03-12
Filing date: 1973-03-12
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28

Abstract

A closure device which is mounted movably on a support member for substantially covering an article disposed thereon. The closure device includes a resilient pad and a sheet member coterminous therewith throughout the contact area therebetween. In the contact area, the sheet member substantially fills the interstices of the resilient pad. The foregoing abstract is neither intended to define the invention disclosed in the specification, nor is it intended to be limiting as to the scope of the invention in any way.

Description

[ May 28, 1974 United States Patent [1 1 Curtis Primary Examiner-Samuel S. Matthews PLATEN COVER w, a b h a R S e m n a M M J wC ,m ,mmm m .MAJ H HI. .1 mom Vl C wmn uh AAP.

. m .I o n 0 .B .U 1. m u 0 W 0 M C d x m ,8 e D X n e 60L m n .w v w m A .1] 5 3 7 7 Conn.

ABSTRACT A closure device which is mounted movably on a support member for substantially covering an article disposed thereon.

M'C M55 1 211 95? M Filed:

Appl. No.: 340,156

The closure device includes a resilient pad and a sheet member coterminous therewith throughout the contact area therebetween. In the contact area, the

62 NM 57 52 .0 m G 5 m U St Um l] 21 55 93 sheet member substantially fills the interstices of the resilient pad.

[58] Field of Search.......................... 355/75 References Cited UNITED STATES PATENTS The foregoing abstract is neither intended to define the invention disclosed in the specification, nor is it intended to be limiting as to the scope of the invention in any way.

3,615,134 Newcomb.............i............... 355/75 3.685305 8/1972 Marshall................... 355/75 11 Claims, 3 Drawing Figures PATENTEDMAYZB 1974 saw 1 or 2 1 PLATEN COVER BACKGROUND OF THE INVENTION This invention relates generally to an electrophotographic printing machine, and more particularly concerns a device utilized to cover an original document disposed on a support member in the printing machine.

A typical electrophotographic printing machine is provided with a transparent platen upon which the original document is supported. The printing machine includes an optical system arranged to create a light image of the original document. The light image is projected onto a charged photoconductive surface. Areas of the charged photoconductive surface irradiated by the light image are discharged recording thereon an electrostatic latent image corresponding to the original document. Generally, the machine is provided with a suitable cover to prevent extraneous light from entering the optical system during the imaging process. Furthermore, the cover is adapted to reflect light rays from the machine optical system preventing development of the border regions extending beyond the original document. The cover usually has a rigid outer shell with a suitable light weight rubber material secured thereto and arranged to engage the original document. Preferably, the rubber material is flexible and colored white so as to reflect light rays therefrom. A cover of this type is disclosed in U.S. Pat. No. 3,642,37l issued to .lonesv ct al. in I972.

Preferably the cushion of the platen cover should be soft and conformable to a thick document, thereby permitting a book or the like to be disposed upon the transparent platen of the printing machine, enabling the pages thereof to be reproduced. The surface in contact with the platen glass and the four sides thereof are, preferably, made from a light reflecting material, i.e. a white colored material, and are smooth. More over, the exterior surface is designed to achieve substantially optimum reflectivity, gloss, hardness and ozone resistivity. The latter is particularly significant in an electrophotographic printing machine wherein the presence of ozone may deteriorate the cushion.

Heretofore, various techniques have been utilized to produce such a cushion which is readily securable to a substantially rigid shell forming a suitable platen cover. Techniques previously utilized include lamination of white plastics and elastomers to a sheet of urethane foam. Other approaches include spraying a white coating on a sheet of urethane foam. The lamination procedure did not prove satisfactory inasmuch as the sides of the cushion and the edges thereof prove to be unacceptable. Moreover, the overall appearance of the cushion was not esthetically pleasing. The technique of spraying a white coating on the sheet of urethane foam also proved to be somewhat inadequate in that it was extremely difficult to obtain a smooth outer surface.

Accordingly, it is a primary object of the present invention to improve the cushion of a platen cover utilized in an electrophotographic printing machine.

SUMMARY OF THE INVENTION Briefly stated, and in accordance with the present invention, there is provided a movably mounted closure device adapted to engage and substantially cover an article.

In the present instance, the closure device includes a resilient pad and sheet member. The sheet member is coterminous with the resilient pad throughout the contact area therebetween. When the closure device is in the closed position the sheet member is arranged to be interposed between the resilient pad and the article substantially in contact therewith. Pursuant to the present invention, the sheet member fills the interstices of the resilient pad throughout the contact area therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIG. 1 is a schematic perspective view of an electrophotographic printing machine employing the present invention therein;

FIG. 2 is an elevational view, partially in section, depicting the platen cover of the present invention pivoted to an intermediate position; and

FIG. 3 is an enlarged sectional elevational view taken along the lines 3-3 of FIG. 2.

While the present invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION With continued reference to the drawings wherein like reference numerals have been used throughout to designate like elements, FIG. 1 schematically ilustrates an electrophotographic printing machine in which the present invention may be incorporated. The electrophotographic printing machine, depicted schematically in FIG. 1, illustrates the various components utilized therein for producing multi-color copies from a colored original. Although the platen cover of the present invention is particularly well adapted for use in an electrophotographic printing machine, it should become evident from the following description that it is equally well suited for use in a wide variety of machines and is not necessarily limited in its application to the particular embodiment shown herein.

As illustrated in FIG. 1, the printing machine employs a photoconductive member having a drum, indicated generally by the reference numeral 10, mounted rotatably within the machine frame (not shown). Photoconductive surface 12 is entrained about and secured to the exterior circumferential surface of drum 10. One type of suitable photoconductive material is disclosed in U.S. Pat. No. 3,655,377 issued to Sechak in 1972. Drum 10 is positioned in the printing machine such that it moves sequentially through a series of processing stations as it rotates in the direction of arrow 14. A main drive motor rotatesdrum 10 at a predetermined speed relative to the various machine operating mechanisms. The machine logic coordinates the operating stations of the machine with one another to produce the proper sequence of events at the respective station.

As shown in FIG. 1, drum 10 initially rotates photoconductive surface 12 through charging station A. A corona generating device, indicated generally at 16, is

positioned thereat. Preferably, corona generating device 16 extends in a generally transverse direction across photoconductive surface 12. Photoconductive surface 12 is charged by corona generating device 16 to a relatively high substantially uniform potential. Preferably, corona generating device 16 is of a type described in U.S. Pat. No. 2,778,946 issued to Mayo in 1957.

After photoconductive surface 12 is charged, drum rotates to exposure station B. At exposure station B, a filtered light image of the original document is projected onto the charged photoconductive surface 12. A moving lens system, generally designated by the reference numeral 18, and a color filter mechanism, shown generally at 20, are located at exposure station B. A suitable moving lens system is disclosed in U.S. Pat. No. 3,062,108 issued to Mayo in 1962, and a suitable color filter mechainsm is described in copending application Ser. No. 830,282 filed in 1969. An original document 22, such as a sheet of paper, book, or the like, is placed face down upon a support member, indicated generally at 68, which includes a transparent viewing platen 24. Lamp assembly 26, lens system 18 and filter mechanism 20 are moved in a timed relation with drum 10 to scan successive incremental areas of original document 22 disposed upon platen 24. Thus, a flowing light image of original document 22 is created and, in turn, projected onto photoconductive surface 12. Filter mechanism 20 is arranged to interpose selected color filters into the optical light path. The machine logic, in association with filter mechanism 20, actuates the appropriate color filter to operate on the light rays transmitted through lens 18, and thereby record an electrostatic latent image on photoconductive surface 12. The electrostatic latent image recorded on photoconductive surface 12 corresponds to a preselected spectral region of the electromagnetic wave spectrum, hereinafter referred to as a single color electrostatic latent image.

With continued reference to FIG. 1, drum 10 rotates the single color electrostatic latent image recorded on photoconductive surface 12 to development station C. Threee individual developer units, generally indicated by the

reference numerals

28, 30 and 32, respectively, are disposed at development station C. The developer units render the electrostatic latent image recorded on photoconductive surface 12 visible. A typical development station employing a plurality of developer units is disclosed in copending application Ser. No. 255,259, filed in 1972. The developer units thereof, are, preferably, all of the type referred to generally as magnetic brush developer units and utilize a magnetizable developer mix comprising carrier granules and toner particles therein. The developer mix is continually brought through a directional flux field to form a brush thereof. Development is achieved by bringing the electrostatic latent image recorded on photoconductive surface 12 into contact with the brush of developer mix. Thus, the toner particles are attracted electrostatically from the brush of developer mix to the electrostatic latent image recorded on photoconductive surface 12. In the multicolor electrophotographic printing machine hereindescribed, each of the respective developer units contains discretely colored toner particles. The toner particles thereof correspond to the complement of the spectral region of the wave length of light transmitted through filter 20. For example, a green filtered electrostatic latent image is rendered visible by depositing green absorbing magneta toner particles thereon. Blue and red latent images are developed with yellow and cyan toner particles, respectively.

After the electrostatic latent image recorded on photoconductive surface 12 is developed with the appropriately colored toner particles, drum 10 is rotated to transfer station D. At transfer station D, the toner particles adhering electrostatically to photoconductive surface 12 in image configuration, are transferred to a sheet of final support material 34. Final support material 34 may be, amongst others, plain paper or a polysulfone thermoplastic sheet. However, it is evident to one skilled in the art that many transparent as well as opaque materials are available which may be formed into sheets to receive multi-color images thereon. A transfer roll, shown generally at 36, is arranged to recirculate support material 34. Transfer roll 36 is biased electrically to a potential of sufficient magnitude and polarity to attract electrostatically the toner powder image recorded on photoconductive surface 12 to support material 34. One such suitably electrically biased transfer roll is described in U.S. Pat. No. 3,612,677 issud to Langdon et al., in 1971. Each of the single color tonerpowder images developed on photoconductive surface 12 are transferred to support material 34 in superimposed registration with one another. To this end, transfer roll 26 is arranged to rotate in synchronism with drum 10. Thus, support material 34 is secured releasably on transfer roll 36 for movement in a recirculating path therewith. As shown in F 16. l, transfer roll 36 rotates in the direction of arrow 38 while drum 10 rotates in the direction of arrow 14. Both transfer roll 36 and drum 10 are driven by a common drive motor through a series of gears arranged such that drum l0 and transfer roll 36 rotate at substantially the same angular velocity.

Support material 34 is advanced from stack 40 disposed on tray 42. Feed roll 44, in operative communication with retard roll 46, advances and separates the uppermost sheet from stack 40. The advancing sheet moves into chute48 which guides it into the nip between register rolls 50. Thereafter, gripper fingers 52 mounted on transfer roll 36 secure releasably thereon support material 34 for movement in a recirculating path therewith. After the requisite number of toner powder images have been transferred to support material 34, gripper fingers 52 space support material 34 from transfer roll 36. This enables stripper bar 54 to be interposed between the underside of support material 34 and transfer roll 36, thereby causing support material 34 to be separated from transfer roll 36. After support material 34 is separated from transfer roll 36, it is advanced on an endless belt conveyor 56 to fixing station E. At fixing station E, a suitable fuser, indicated generally at 60, coalesces the transferred powder images to support material 34. U.S. Pat. No. 3,498,592 issued to Moser et al. in 1970 describes one type of suitable fuser which is adapted to coalesce the transferred toner poweder image to support material 34. After the fusing process, support material 34 with the multi-color image affixed permanently thereto is advanced by

endless belt conveyors

60 and 62 to catch tray 64. At catch tray 64, the machine operator removes the copyfrom the printing machine.

Although a preponderance of toner particles are transferred to support material 34, invariably some residual particles remain on photoconductive surface 12 after the transfer of the toner powder image to support material 34. These residual toner particles are removed from photoconductive surface 12 as drum moves through cleaning station F. At cleaning station F, the residual toner particles are initially brought under the influence of a cleaning corona generating device (not shown). The corona generating device is adapted to neutralize the electrostatic charge remaining on the residual toner particles. This enables a rotatably mounted fibrous brush 66 to mechanically clean the neutralized toner particles from photoconductive surface 12. Brush 66 is positioned in cleaning station F contacting photoconductive surface 12. Hence, the residual toner particles remaining on photoconductive surface 12 after each successive transfer operation are readily removed therefrom. A suitable brush cleaning device is described in U.S. Pat. No. 3,590,412 issued to Gerbasi in 197l.

It is believed that the foregoing description is sufficient for purposes of the present application to illustrate the general operation of a multi-color electrophotographic printing machine embodying the teachings of the present invention.

Referring now to the specific subject matter of the present invention, FIG. 2 depicts the platen cushion thereof in detail. As shown in FIG. 1, the electrophotographic printing machine includes a stationary support member 68 having a substantially rectangular platen 24. Platen 24 is, preferably, made of glass and secured by suitable means to the frame of the electrophotographic printing machine. Transparent platen 24 rests upon resilient means or a soft edge gasket 69 secured to horizontally dependent flange 70 of the rigid machine frame. A plate 72 is affixed to the machine frame and placed over platen 24. Plate 72 includes an opening therein to expose a top surface of platen 24.

A closure device or platen cover, indicated generally at 74, is mounted pivotably along one edge of support member 68 and includes a substantially rigid continuous outer shell 76 and a resilient pad 78 secured thereto. Preferably, outer shell 76 is made from a suitable plastic material. Sheet member 80 is conterminous with resilient pad 78 throughout the contact area there'- between. Moreover, sheet member 80 is arranged to be interposed between original document 22 and resilient pad 78 when cover 74 is in the closed position. Sheet member 80 is molded integrally with resilient pad 78 and adapted to fill the interstices throughout the entire contact area therebetween. Thismolding process will be described hereinafter in greater detail with reference to FIG. 3.

A handle 82 is provided at the free end of cover 74 and provides a means by which cover 74 may be raised and lowered. To permit cover 74 to be raised over large objects to be reproduced, such as books, while still, permitting cover 74 to lie in a plane substantially parallel to platen 24, cover 74 is double hinged. Double hinge 84 is arranged to secure cover 74 at the end thereof opposed from handle 82. A suitable double hinge is described in U.S. Pat. No. 3,062,110 issued to Shepardson et al. in 1962.

In particular, the present invention is concerned with producing a sheet member 80 secured to resilient pad 78 such that the interstices of the contact area therebetween are filled. In this manner, resilient pad 78 is secured to sheet member 80. Resilient pad 78 is preferably made from a polyurethane foam material, while sheet member is also preferably made from a light reflecting i.e., white polyurethane elastomer. Preferably, the thickness of sheet member 80 ranges from about several mils to about 1/ 16th of an inch maximum.

As shown in region 86 of FIG. 3, sheet member 80 uniformly fills the interstices of resilient pad 78 throughout the contact area therebetween. This insures that sheet member 80 is tightly bonded to resilient pad 78 over the entire contact area. Sheet member 80 is adapted to surround substantially all of the surfaces of resilient pad 78, exclusive of surface 88 which is secured to outer shell 76. The foregoing is achieved by a suitable molding process which will hereinafter be described.

In forming a suitable platen cushion which includes sheet member 80 and resilient pad 78, a suitably configured mold of metal, silicon rubber, or epoxy has the interior surface thereof sprayed with a polyurethane elastomeric coating. Preferably, the foregoing elastomeric coating is white or any other suitable light reflective material. One such suitable material is available under the tradename Neothane from the Goodyear Tire and Rubber Company in Akron, Ohio. This initial coating corresponds to sheet member 80 and is arranged to encompass all of the surfaces of resilient pad 78 which is subsequently to be molded in the mold, exclusive of the surface thereof arranged to be in engagement with outer shell 76. After the elastomeric coating corresponding to sheet member 80 is sprayed in the mold, it is allowed to cure for a short period,.whereupon the mixed chemicals of the polyurethane foam of resilient pad 78 is dispensed therein. The liquid polyurethane expands to fill the spaces in the mold with a foam. The polyurethane foam and the elastomeric skin or coating chemically combine such that the interstices of the coterminouscontact area therebetween are integral with one another. Thus, resilient pad 78 and sheet member 80 form a composite platen cushion adapted to be secured to outer shell 76. In the foregoing process, the surface finish of sheet member 80 is dependent upon the characteristics of the mold surface. Furthermore, the color of sheet member 80 may be suitably varied by changing the color of the polyurethane spray being applied to the mold interior surface. In addition, the physical characteristics of the platen cush-' ion can be suitably adjusted by varying the polyurethane constituents or by utilizing other suitable materials so as to obtain the requisite properties therefore.

While the foregoing embodiment has been described in conjunction with a resilient pad integral with a sheet member to form a platen ,cushion separate from the cover of the outer shell, it is evident to one skilled in the art that both the resilient pad and sheet member may be suitably molded to the outer shell. Thus, it is apparent that if desired, a completely integral platen cover 74 may be formulated by the foregoing process, i.e. resilient pad 78'may be molded to outer shell 76 while sheet member 80 may be suitably molded to resilient pad 78 as heretofore described.

In recapitulation, platen cover 74 includes an outer shell 76 having a resilient pad 78 secured thereto. Furthermore, sheet member 80, which is fabricated from a light reflecting material, is adapted to be coterminous with resilient pad 78 over substantially the entire contact area therebetween. The molding process heretofore described issuch that interstices 86 between sheet member 80 and resilient pad 78 are filled forming an integral bond therebetween. This molding process produces an esthetically pleasing platen cushion having a light reflecting surface on substantially all of the exposed exterior surfaces thereof while maintaining the surface in contact with the outer shell substantially free therefrom. Hence, the platen cover of the present invention may be readily utilized in an electrophotographic printing machine to insure that the border regions surrounding the image remain undeveloped and are the color of the original support material, i.e. they do not have any toner particles deposited thereon.

Thus, it is apparent that there have been provided, in accordance with the present invention a closure device that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.

What is claimed is:

l. A movably mounted closure device adapted'to engage and substantially cover an article disposed'on a support member, including:

a resilient pad having interstices on at least one of its surface areas; and i a sheet member having a surface areas coterminous with said resilient pad substantially throughout said surface area of said pad and arranged to be interposed between the article and said resilient pad when the closure device is in the closed position, said sheet member surface area filling the interstices of said resilient pad substantially throughout the contact area therebetween.

2. A device as recited in claim 1, further including a substantially rigid outer shell secured to the surface of said resilient pad opposed from said sheet member, said outer shell being mounted pivotably on the support member.

3. A device as recited in claim 2, wherein said sheet member is made-of a light reflecting material.

4. A device as recited in claim 3, wherein said light reflecting material is made of a white polyurethane material having a maximum thickness of about 1/16 inch.

"5. A device as recited in claim 4, wherein said resilient pad is made of a polyurethane material.

6. An electrophotographic printing machine of the type having a corona generating device for charging a photoconductive surface to a substantially uniform potential, and an exposure mechanism for creating a light image of an original document arranged to be recorded on the charged photoconductive surface, wherein the improvement includes:

a support member mounted on the printing machine, said support member being arranged to hold the original document in a light projecting relationship with the exposure mechanism for recording the light image thereof on the charged photoconductive surface; and cover member mounted movably on said support member, said cover member comprising a resilient pad having interstices on at least one of its surface areas, and a sheet member having a surface area coterminous with the resilient pad substantially throughout said surface area of said pad and arranged to be interposed between the original document and the resilient pad when said cover member is in the closed position, said sheet member surface area filling the interstices of the resilient pad substantially throughout the contact area therebetween.

7. A printing machine as recited in claim 6, wherein said cover member further includes a substantially rigid outer shell secured to the surface of the resilient pad opposed from the sheet member, said outer shell being mounted pivotably on said support member.

. 8. A printing machine as recited in claim 6, wherein said support member includes:

a substantially rigid frame secured to the printing machine, said frame having an aperture therein; resilient means secured to said frame member on the periphery of the aperture therein; and

a transparent member having a generally planar surface, said transparent member being mounted on said resilient means in the aperture of said frame member permitting light rays to be transmitted therethrough.

9. A printing machine asrecited in claim 6, wherein the sheet member of said cover member is made of a light reflecting material. v

10. A printing machine as recited in claim 9, wherein the light reflecting material of said cover member is made of a white polyurethane material having amaximum thickness of about 1/16 inch.

11. A printing machine as recited in claim 10, wherein the resilient pad of said cover member is made of a polyurethane material.

Claims

1. A movably mounted closure device adapted to engage and substantially cover an article disposed on a support member, including: a resilient pad having interstices on at least one of its surface areas; and a sheet member having a surface areas coterminous with said resilient pad substantially throughout said surface area of said pad and arranged to be interposed between the article and said resilient pad when the closure device is in the closed position, said sheet member surface area filling the interstices of said resilient pad substantially throughout the contact area therebetween.

3. A device as recited in claim 2, wherein said sheet member is made of a light reflecting material.

5. A device as recited in claim 4, wherein said resilient pad is made of a polyurethane material.

6. An electrophotographic printing machine of the type having a corona generating device for charging a photoconductive surface to a substantially uniform potential, and an exposure mechanism for creating a light image of an original document arranged to be recorded on the charged photoconductive surface, wherein the improvement includes: a support member mounted on the printing machine, said support member being arranged to hold the original document in a light projecting relationship with the exposure mechanism for recording the light image thereof on the charged photoconductive surface; and a cover member mounted movably on said support member, said cover member comprising a resilient pad having interstices on at least one of its surface areas, and a sheet member having a surface area coterminous with the resilient pad substantially throughout said surface area of said pad and arranged to be interposed between the original document and the resilient pad when said cover member is in the closed position, said sheet member surface area filling the interstices of the resilient pad substantially throughout the contact area therebetween.

8. A printing machine as recited in claim 6, wherein said support member includes: a substantially rigid frame secured to the printing machine, said frame having an aperture therein; resilient means secured to said frame member on the periphery of the aperture therein; and a transparent member having a generally planar surface, said transparent member being mounted on said resilient means in the aperture of said frame member permitting light rays to be transmitted therethrough.

9. A printing machine as recited in claim 6, wherein the sheet member of said cover member is made of a light reflecting material.

10. A printing machine as recited in claim 9, wherein the light reflecting material of said cover member is made of a white polyurethane material having a maximum thickness of about 1/16 inch.