US3612681A

US3612681A - Electrophotographic copying device

Info

Publication number: US3612681A
Application number: US816568A
Authority: US
Inventors: Yoshio Itoh
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1968-04-25
Filing date: 1969-04-16
Publication date: 1971-10-12
Anticipated expiration: 1988-10-12
Also published as: DE1920650A1; DE1920650B2; JPS5134300B1; NL6906441A

Abstract

The present invention provides an electrophotographic copying device of the type in which a copy paper is maintained in direct contact with an original to be copied. The device includes auxiliary separating means in the form of an elongated strip interposed between marginal portions of the copy paper and the original along one side of the advancing passage of the copy paper and original and separating means cooperating with said auxiliary separating means to separate the copy paper from the original.

Description

United States Patent Yoshio Itoh Kokubunji-shi, Tokyo, Japan 816,568 Apr. 16, 1969 Oct. 12, 1971 Canon Kabushki Kaisha Tokyo, Japan Apr. 25, 1968 Japan Inventor App]. No. Filed Patented Assignee Priority ELECTROPIIOTOGRAPHIC COPYING DEVICE 6 Claims, 6 Drawing Figs.

Int. Cl

FieldofSearch ..355/l2, I10

[56] Reierences Cited UNITED STATES PATENTS 3,022,716 2/1962 Smith 355/110 3,498,709 3/1970 Kaminstein... 355/ l 2 Primary Examiner-Samuel S. Matthews Assistant Examiner-E. M. Bero Attorney-Watson, Leavenworth & Kelton ABSTRACT: The present invention provides an electrophotographic copying device of the type in which a copy paper is maintained in direct contact with an original to be copied. The device includes auxiliary separating means in the form of an elongated strip interposed between marginal portions of the copy paper and the original along one side of the advancing passage of the copy paper and original and separating means cooperating with said auxiliary separating means to separate the copy paper from the original.

ELECTROPIIOTOGRAPIIIC COPYING DEVICE The present invention relates to an electrophotographic copying device and more particularly an electrophotographic device provided with improved means for separating a copy paper from an original.

In electrophotography, for example, of the direct-contactexposure type, a copy paper having a photosensitive layer is unifonnly electrically charged before or after the copy paper is superposed on an original to be copied and the copy paper,

while in the superposed relation with the original, is directly exposed or exposed by reflected lights, thereby forming on the photosensitive layer an electrostatic latent image corresponding to the original. Thereafter, the copy paper, which has been electrically attracted to the original, is separated therefrom and the electrostatic latent image formed on the photosensitive layer of the copy paper is developed by a suitable developing agent having an electrical polarity. The developed image is fixed to the copy paper by a suitable means.

In the copying device 7' use in the above-described method, the copy paper is closely contacted with the original so that special means must be provided for separating the copy from the original prior to practice of the next step. For this purpose,

there have been proposed various methods or systems.

In one of these prior methods, in order to easily separate the copy paper from the original in the separating step, the leading edge of the copy paper is displaced from that of the original by approximately one-fourth inch when they are superposed and advanced into the copying device. Another method is such that the original is held in an auxiliary separating sheet. In all these methods, the copying operation is very tedious and the construction of the copying device is complicated so that, due to erroneous operation or defects in the construction of the device, it frequently occurs that the original is erroneously advanced into the developing section and is damaged.

In another method, the copy paper and the original are advanced by a pair of feed rollers having different peripheral speeds so that the leading edges of the copy paper and the original are displaced from each other and in this state advanced toward the separating position. However, when such method is utilized in the direct-contact-exposure system, the original and the copy paper are charged and exposed in superposed relation, or the previously electrically charged copy paper is superposed upon the original and then exposed, so that they are electrostatically attracted to each other, thereby making it difficult to separate the copy paper from the original. That is, even by the above-described separating method, separation is still difiicult.

A further separating method disclosed is such that between the original and the copy paper there is interposed a length of a thread, 'wire or sheet or the like during the time when the copy paper is superposed upon the original and the photosensitive layer is electrically charged and exposed. However, in order that better quality electrostatic latent images may be formed, the use of this separating means is not preferable.

The primary object of the present invention is to provide an electrophotographic copying device incorporating therein means for easily separating an original from a copy paper. According to the present invention, this can be attained by the provision of auxiliary separating means, in the form of an elongated striplike material extending between marginal portions of the original and the copy paper along one side of the passage of their advancement, which will not adversely affect the copying operation, and wedge-shaped separating means disposed in the vicinity of said auxiliary separating means.

Another object of the present invention is to provide an electrophotographic copying device incorporating therein a novel means for positively separating an original from a copy paper, thus completely eliminating the defects encountered in conventional separating means.

Another object of the present invention is to provide an electrophotographic copying device incorporating therein separating means and auxiliary separating means for easily separating an original from a copy paper.

A further object of the present invention is to provide an electrophotographic copying device incorporating therein a novel separating means which requires no power to drive the same for separating an original from a copy paper.

Other objects and advantages of the present invention will become apparent to those skilled in the art in the course of the following description.

In brief, according to the present invention, an original and a copy paper are advanced with an auxiliary separating means being interposed therebetween along one side of the passage thereof while the copy paper is charged and exposed. At the end portion of said auxiliary separating means are disposed wedge-shaped separating members having incliningside edges transversely of said passage, whereby the original and the copy paper are easily separated respectively transversely of said passage from the side of said auxiliary separating means toward the opposite side.

The above and other objects, features and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings, in which:

FIG. I is a sectional view of an embodiment of an electrophotographic photocopying device according to the present invention:

FIG. 2 is a perspective view of essential portions inside the device shown in FIG. 1;

FIG. 3 is a plan view of the inside of the device of FIG. 1;

FIG. 4 is a perspective view of a copy-original-separating mechanism incorporated in the device of FIG. I;

FIG. 5 is a perspective view of pressure plates disposed below the exposure device incorporated in the copying device of FIG. 1; and

FIG. 6 is a sectional view of another embodiment of the present invention.

Referring to FIGS. 1 to 5 illustrating an embodiment of the present invention, a copy paper 1 is guided by a guide plate 2 attached to a machine frame 100. Above the copy guide plate 2 is disposed an original guide plate 4 for separating the original 3 from the copy 1 and guiding the original. The original guide plate 4 is attached to the sideplate 45 as best shown in FIG. 2. A pair of

feed rollers

5 and 6 is disposed backwardly of both of the

guide plates

2 and 4 and rotatably joumaled between sideplates 60. At least one of the

feed rollers

5 or 6 is driven by a driving means such as motor not shown. Backwardly of the pair of

feed rollers

5 and 6 are disposed charging devices 7 and 740 for imparting charge to the copy paper 1. The charging devices 7 and 7' are mounted upon the sideplates 60 respectively through supporting members not shown and have corona electrodes 70 and 70' surrounded by shield cases 71 and 7l The

electrodes

70 and 70 are connected to the opposing polarity terminals of a highvoltage source not shown. An exposure device 8 is disposed backwardly of the charging devices 7 and 7' for forming an electrostatic image upon the copy paper 1 and comprises an exposure light source 9, a hood covering the upper half of the light source 9 and a shield frame 19 for preventing transmission of light in undesired directions. The exposure device 8 is disposed between the sideplates 60 through a suitable support. Immediately below the exposure light source 8 are disposed

pressure plates

10 and 10 for guiding the superposed original 3 and the copy paper 1 and light emanating from the exposure lamp 9 illuminates the copy paper 1 through the pressure plate 10. For this purpose, the pressure plate must be transparent. Immediately backwardly of the exposure device 8 are disposed a pair of

delivery rollers

11 and 12 joumaled rotatably between the sideplates 60. At least one of these delivery rollers must be driven by a suitable drive means such as motor not shown. A pair of

original delivery rollers

13 and 14 are rotatably joumaled between the sideplates 60 for delivering or discharging the original 3 out of the photocopying machine into for example a tray disposed outside of the machine. In order that the original 3 may be transported or advanced forwardly and substantially horizontally, it is preferable that the copy paper and

original guide plates

2 and 4, the pair of

feed rollers

5 and 6, the charging device 7 and 7' the exposure device 8 and the pairs of

delivery rollers

11 and 12, 13 and 14 are all disposed at the same height.

Below the pairs of

delivery rollers

11 and 12 are disposed a pair of

rollers

15 and 16 for advancing the copy paper bearing thereupon the electrostatic latent image toward the developing section. As in the case of the other pairs of rollers, at least one of the

rollers

15 or 16 must be driven by suitable drive means such as motor not shown. In order to prevent the destruction of the electrostatic latent image upon the copy paper 1, the

rollers

12 and 16 must be made of an electrically insulating material. Reference numeral 17 designates a developing device for developing the electrostatic image upon the copy paper 1 into a visible image and is shown as a liquidtype developing device. A pair of guide plates 43 are disposed within the developing device 17 and a pair of

rollers

21 and 41 are provided for squeezing out the developing solution remaining upon the copy paper. Any other suitable developing device,- for example, magnetic brush developing device, powder cloud developing device and the like may be utilized as the developing device 17. A guide plate 18 for image fixing is so arranged that heated air from an air-heating fan 20 disposed above the guide plate 18 may be directed upon the surface of the copy paper 1 passing over the guide plate 18. A pair of

delivery rollers

22 and 42 are disposed for delivering or discharging the processed copy paper 1 out of the photocopying machine into a tray not shown. The pairs of rollers 15 and I6, 21 and 41, and 22 and 42 are rotatably supported between the sideplates 60. At least one roller of each pair of rollers must be driven by drive means not shown.

Next referring particularly to FIG. 4, the original-copypaper-separating device, the features of which are the principal characteristic of the present invention, will now be described in detail. Reference numeral 23 designates an auxiliary separating member for preventing the marginal portions of copy paper 1 and the original 3 from contacting each other. The auxiliary separating member 23 is in the form of an elongated strip, extending along one side of the passage of the original and copy paper from the outlet side of the original guide plate 4, toward the original-copy-separating members which will be described in more detail hereinafter, in such a manner that the copying operation will not be affected by this arrangement of the auxiliary separating member 23. As shown in FIG. 4, the auxiliary separating member 23 is securely fixed to the guide plate 4. Preferably, the auxiliary separating member 23 is made of an electrically insulating (insulative), smooth, sheetlike material. The rear end portion of the auxiliary separating member 23 is disposed in contact with the separating member which will be described hereinafter. Relief portions or reduced-

diameter portions

28 and 51 are formed at one side portions of the

feed rollers

5 and 6 respectively.

Similar relief portions

29 and 52 are formed at one side portions of the pair of

delivery rollers

11 and 12. The diameters of these relief portions are smaller than those of the rollers.

FIG. 5 illustrates the pressure plates 10 and 10' disposed below the exposure device 8.

Relief portions

53 and 54 are formed in the pressure plates 10 and 10' respectively and the thickness of the relief portion is less than that of its corresponding pressure plate.

Referring again to FIG. 4, reference numeral 27 designates a wedge-shaped separating member attached to the sideplates and the leading edge of the separating member 27 contacts'the auxiliary separating member 23 and is disposed immediately backwardly of the roller 12. The separating member 27 is curved so as to guide the copy paper bearing the electrostatic image thereupon and being delivered from the pair of

rollers

11 and 12. Reference numeral indicates the curving side edge of the separating member 27 for separating the copy paper from the original from the side close to the auxiliary separating member 23 toward the opposite side thereof transversely of the copy paper and the original. Reference numeral 26 is another separating member having a flat surface and being disposed in a wedge shape so as to provide an inclining side edge 24. It should be noted that this separating member is secured below the end of the auxiliary separating member 23. Preferably both of the separating

members

26 and 27 are made of an electrically insulating, thin and smooth sheetlike material. It is also preferable that the angle a of the wedge formed by the curving side edges 24 and 25 of the separating

members

26 and 27 is within the range of from 5 to Next the mode of operation of the device having the construction as described hereinabove will be described. First, the copy paper 1 is placed upon the guide plate 2 with the photosensitive layer of the copy paper 1 being directed downwardly while the original 3 is placed upon the guide plate 4 with the image of the original to be copied being directed downwardly. The copy paper 1 and the original 3 are fed into the pair of

rollers

5 and 6 simultaneously. It must be noted that the auxiliary separating member 23 is interposed between the copy paper 1 and the original 3 and that the original 3 and the copy paper 1 are advanced by the rollers while being partially separated from each other by the auxiliary separating member through the charging and exposure devices until they are finally separated from each other by the separating

members

26 and 27. The photosensitive layer of the copy paper 1 is sensitized by corona discharge between the pair of

corona discharge electrodes

70 and 70 of the discharging devices 7 and 7'.

Thereafter, the image of the original is projected upon the copy paper 1 by the exposure lights from the fluorescent lamp 9 in the exposure device 8 through the transparent pressure plate 10 so that the electrostatic latent image corresponding to the image pattern of the original 3 is formed. After exposure, both of the copy paper 1 and the original 3 are advanced toward the pairs of

delivery rollers

11 and 12 by means of suitable transporting or advancing means such as rollers drivingly connected to an electric motor not shown and after passing through the delivery rollers, the copy paper is separated from the original.

According to the present invention, the elongated striplike auxiliary separating member 23 extends from the guide plates toward the position at which the copy paper 1 is separated from the original 3, one lateral side (marginal) portion of the copy paper 1 and the original 3 being spaced apart while being advanced after having been electrically charged. Said one lateral side portion of the copy paper 1 advanced through the relief portion 52 formed in the roller 12 and the auxiliary separating member 23 abuts against the separating member 27 having the curved side edge 25 disposed backwardly of the pair of

rollers

29 and 52 so that the copy paper 1 is separated from the original 3 from the side edge on the side of the auxiliary separating member 23 toward the opposite side transversely of the copy paper 1 by the curving side edge 25 as the copy paper 1 is advanced. The separated copy paper 1, bearing thereupon the electrostatic latent image, is guided downwardly by the separating member 27 into the pair of

feed rollers

15 and 16. The copy paper 1 emerging from the

feed rollers

15 and 16 is passed through a copy guide 43 disposed in the liquid developing device, in which the electrostatic image upon the copy paper 1 is developed. Thereafter, the copy paper 1 is directed toward the pair of squeezing and

delivery rollers

21 and 41 and fixed and dried upon the guide plate 18 by the heated air delivered from the fan 20. Thereafter, the copy paper having a visible image is discharged out of the photocopying machine through the pair of

delivery rollers

22 and 42.

Said one lateral side portion of the original 3 emanating between the relief portion 29 formed in the roller 11 and the auxiliary separating member 23 is directed toward the separating member having the curved side edge 24. ln a similar manner as described above, as the original 3 is advanced, it is separated from the copy paper 1 from the side of the auxiliary separating member 23 toward the opposite side transversely of the original by the curved side edge 24 and advanced along the separating member 26 which also serves as a guide plate toward the pair of

delivery rollers

13 and 14, from which the original 3 is discharged out of the photocopying machine.

FIG. 6 illustrates another embodiment of the exposure device incorporated in the photocopying device according to the present invention. The copy paper 1 is advanced while one side edge portion thereof is maintained in spaced-apart relation with the original 3 and is electrically charged by the charging devices 7 and 7' having the shield cases 71 and 71' surrounding the charging electrodes 70 and 70' having opposite polarities. Thereafter, the copy paper 1 is exposed by the lights transmitted through the exposure pressure plate 10" from the exposure device comprising an exposure light source 9 such as fluorescent lamp, a hood 90' covering the upper half of the light source 9' and a shield frame 19' for preventing propagation of light in undesired directions. Concurrently with the exposure, the copy paper 1 is further electrically charged by a charging device 32 having a shield 30 which surrounds a charging electrode 31 as shown in FIG. 6. By this device, an electrostatic latent image having a higher contrast as compared with that of the electrostatic latent image formed by thefirst embodiment of the present invention can be attained. Thereafter, in the similar manner as described with reference to the first embodiment, the copy paper is developed, fixed and discharged out of the photocopying machine. In the second embodiment, a visible image having high contrast can be obtained.

In the electronic photographic photocopying device of the present invention, the superposed copy paper 1 and the original 3 are advanced in the state in which they are attracted to each other electrostatically after having been uniformly charged by the

charging devices

7 and 7 and the auxiliary separating member 23 is provided along one side of the passage of the copy paper and the original in such a manner that the auxiliary separating member 23 will not adversely affect the formation of an electrostatic latent image and so that the copy paper can be easily separated from the original prior to the next step.

Furthennore, edges of the separating

members

26 and 27 are disposed at the end portion of the auxiliary member 23 in such a manner that said edges are in contact with the marginal portions of the copy paper and the original which are separated from each other by the auxiliary separating member 23, that is the portions between which are interposed the member 23. Therefore the leading edges of the copy paper and the original abut against the separating

members

26 and 27 as the copy paper and the original are advanced and separated from each other transversely from the side of the auxiliary separating member 23 toward the opposite side. The copy paper 1 is directed toward the developing device by the separating member 27 which serves as a guide for the copy paper while the original is directed toward the

delivery rollers

13 and 14 through the separating member 26 which also serves as a guide. It will be seen that the copy paper 1 can be separated from the original easily and positively. Furthermore, the separating device according to the present invention will not affect adversely the formation of an electrostatic latent image and will not require any further drive means, for example, individual separating rollers or air-suction mechanism.

The present invention has been so far with particular reference to a direct-contact-exposure-type electrophotographic photocopying machine, but it will be understood that the present invention can be also applied to a contact-reflection-exposure-type photocopying device and to an electrographic device of the type utilizing an electrostatic photocopying method in which a previously electrically charged copy paper is superposed upon an original and exposed, thereby forming an electrostatic image.

What is claimed is:

1. An electrophotographic copying device comprising:

a. guide means in said device for superposing an original atop a copy paper, including a guide plate placeable between said su sed ori and b. pressure roller p aii l s suppor t ii rearufai c ii y a s;id guide plate and adapted to advance therebetween said superposed original and copy paper, opposed marginal portions of said rollers being of reduced diameter;

c. means disposed intermediate said roller pairs for forming an electrostatic image of said original on said copy paper;

d. means disposed rearwardly of said roller pairs for separating said image-bearing copy paper from said original;

e. means for developing said image on said separated copy paper; and

f. an elongated strip member secured to said guide plate and extending therefrom between said opposed roller marginal portions and secured to said separating means.

2. The device claimed in claim 1 wherein said separating means includes a first plate having an edge comprising a first portion secured to said strip member and a second portion tapering rearwardly of said strip member and a second plate having an edge disposed in contact with the undersurface of said strip member.

3. The device claimed in claim 2 wherein said second plate defines an arcuate surface transversely of said strip member.

4. The device claimed in claim 1 wherein said strip member is comprised of an electrically insulative resilient material.

5. The device claimed in claim 2 wherein said plates are comprised of electrically insulative resilient material.

6. The device claimed in claim 1 wherein said electrostatic image-forming means includes first and second plate members having opposed surfaces for receiving therebetween said superposed original and copy paper, opposed marginal portions of said plate member surfaces being recessed, said strip member extending between said recessed surfaces.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,612,681 Dated October 12, 1971 Inventor-(s) YOShiO 11101! It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Item [73] Title page, "Canon Kabushki Kaisha" should read --Canon Kabushiki Kaisha-.

Column 1, line 19, "7'" should read --:Eor--.

Column 2, line 24, should read Column 2, line 46, "740" should read --7'--.

Column 6 lines 11-12, "electrographic" should read -electrophotographic--.

. Signed and sealed this 30th day of May 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, J'H. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents

Claims

1. An electrophotographic copying device comprising: a. guide means in said device for superposing an original atop a copy paper, including a guide plate placeable between said superposed original and copy paper; b. pressure roller pairs supported rearwardly of said guide plate and adapted to advance therebetween said superposed original and copy paper, opposed marginal portions of said rollers being of reduced diameter; c. means disposed intermediate said roller pairs for forming an electrostatic image of said original on said copy paper; d. means disposed rearwardly of said roller pairs for separating said image-bearing copy paper from said original; e. means for developing said image on said separated copy paper; and f. an elongated strip member secured to said guide plate and extending therefrom between said opposed roller marginal portions and secured to said separating means.