JPH04232972A - Electrophotographic device and method for preventing winding of form to photosensitive body - Google Patents

Abstract

PURPOSE:To offer an electrophotographic device and a method in which the sagging of the leading edge of a form is removed and the paper is prevented from being wound around the photosensitive body for a system in which the form is attracted and carried by a transfer belt and transfer is performed. CONSTITUTION:In an electrophotographic device where the accumulated forms 4 are separated and fed one by one, and electrostatically attracted and carried by the transfer belt 10, and held between the transfer belt 10 and the photosensitive body 12 which holds an electrostatic latent image corresponding to printing information and toner electrostatically attracted on the electrostatic latent image so that a toner image on the photosensitive body 12 is transferred to the form 4, the leading edge of the form 4 carried to a transfer part is a little bent toward the photosensitive body 12.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus, and more particularly to a method for preventing paper from wrapping around a photoreceptor, and an electrophotographic apparatus using the method.

0002

2. Description of the Related Art As a known example of a conventional electrophotographic apparatus, as described in Japanese Unexamined Patent Publication No. 2-95668, a combination of an elastic roller and a metal roller is used to curl paper in the direction of peeling it from a photoreceptor. Some attempts have been made to prevent paper from wrapping around the photoreceptor.

0003

[Problems to be Solved by the Invention] However, the above-mentioned prior art does not take into account the wrapping of the paper around the photoreceptor due to sag during cutting of the leading edge of the paper, and the wrapping of the paper around the thin photoreceptor with low bending rigidity. There wasn't.

That is, the number of sheets of paper to be cut at once during cutting, the problem of wrapping around the photoreceptor that occurs at a frequency that is correlated with the number of sheets, and the curling of the paper after printing due to wrapping around the photoreceptor affect the print quality. There was a problem of lowering the .

[0005] The present inventors have discovered that the main cause of paper wrapping around the photoconductor occurs when the leading edge of the paper sag, equivalent to the thickness of the paper, is attached in the direction of separation from the photoconductor when the paper is cut. I found it. In other words, when the leading edge of the paper is sagging in the direction of peeling off from the photoreceptor, a gap layer is created between the paper and the transfer belt, and this gap layer reduces the electrostatic adsorption effect of the transfer belt on the paper, causing the paper to sag. The film wraps around the photoreceptor that it comes into contact with at the transfer section.

An object of the present invention has been made to solve the above-mentioned problems, and in particular, for a system in which paper is attracted to a transfer belt and transferred while being transferred, it is possible to remove sagging at the leading edge of the paper and to remove the paper from the photoreceptor. It is an object of the present invention to provide an electrophotographic apparatus and a method thereof in which paper does not get wrapped around the edges.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a paper feeding device that separates and feeds stacked sheets one by one, and a dielectric device that electrostatically attracts and transports the sheets. An endless transfer belt consisting of an endless transfer belt, a pulley that drives the transfer belt, at least one pulley that tensions the transfer belt, an electrostatic latent image corresponding to print information, and an electrostatic adsorption on the electrostatic latent image. a photoconductor that holds the toner that has been applied to the photoconductor; and in order to transfer the toner image on the photoconductor to a sheet of paper that is being conveyed by the transfer belt, the paper is sandwiched between and brought into contact with the photoconductor and the transfer belt. An electrophotographic apparatus comprising a transfer section, characterized in that a means for slightly bending a leading edge of the paper toward the photoreceptor is provided between the paper feeding device and the transfer section. be.

[0008] Further, between the paper feeding device and the transfer unit, there is provided a support portion that supports the leading edge of the paper, a fixed portion having a rounded corner that contacts the leading edge of the paper, and a fixed portion that supports the leading edge of the paper. A paper leading edge bending means is provided, comprising a moving part that bends the leading edge of the paper located in the gap with the fixed part in the direction of the photoreceptor by moving with a predetermined gap from the fixed part. It is something to do.

[0009] Also, the stacked sheets are separated and fed one by one, and the sheets are electrostatically attracted and conveyed by an endless transfer belt made of a dielectric material, so that an electrostatic latent image corresponding to the print information and a corresponding image are formed. At a transfer section where the paper is sandwiched between and in contact with the transfer belt and a photoconductor that holds toner electrostatically adsorbed on the electrostatic latent image, the toner image on the photoconductor is conveyed by the transfer belt. An electrophotographic device that transfers images onto paper that is
The method for preventing paper from wrapping around the photoreceptor is characterized in that the leading edge of the paper being conveyed to the transfer section is slightly bent toward the photoreceptor.

0010

[Operation] According to the above structure, the leading edge of the paper being conveyed to the transfer section can be slightly bent in the direction of the photoreceptor, so that when the paper is sandwiched between the photoreceptor and the transfer belt, the paper and the transfer belt are There is no void layer between them. Therefore, the electrostatic adsorption effect of the transfer belt works effectively, and the paper does not get wrapped around the photoreceptor.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an electrophotographic apparatus showing an embodiment of the present invention. The sheets 4 accumulated in the hopper 2 are separated and fed one by one and conveyed to the sheet leading edge bending means 6. The conveyance roller 8 conveys the paper 4 to a transfer belt 10, and then the transfer belt 10 conveys the paper 4 to a transfer section where the toner on the photosensitive drum 12 is transferred. The toner image on the photosensitive drum 12 is visualized by a developing device 14 . A transfer corotron 16 is provided on the back side of the transfer belt 10 facing the photosensitive drum 12.
is arranged to electrostatically attract the toner image on the photosensitive drum 12 to the paper 4. Thereafter, the paper 4 is conveyed to the fixing device 18, and the toner image is fixed onto the paper 4. The paper 4 after fixing is carried out to an output tray by a carry-out roller 20. In addition, the apparatus of this embodiment is provided with an optical unit 22 for developing an image on the photosensitive drum 12, a cleaner 24 for cleaning residual toner on the photosensitive drum 12, and the like.

Here, the situation when the leading edge of the paper 4 passes through the transfer section in a conventional electrophotographic apparatus will be described with reference to FIGS. 2 and 3. Cut paper is manufactured by cutting continuous paper using a cutting machine, so the sharpness of the cutting machine and
Depending on the number of sheets of paper at the time of cutting, sagging of different sizes may occur as shown at the leading edge of the paper 4 in FIG. 2. Due to the influence of this sag, a gap layer 26 is formed between the transfer belt 10 and the paper 4.
occurs, and a discharge occurs here to eliminate static electricity. As a result,
The leading edge of the paper 4 is attracted to the photosensitive drum 12, and the paper 4 is attracted to the photosensitive drum 12 as shown in FIG. This sag is as large as about 1.5 times the thickness of the paper, and the size of the sag is determined in one direction and at a cycle of the number of sheets corresponding to the number of sheets at the time of cutting.

In order to eliminate the influence of this sagging in the transfer section and prevent the paper 4 from wrapping around the photosensitive drum 12, it is preferable to bend the leading edge of the paper in the direction opposite to the sagging, that is, toward the photosensitive drum 12. . However, if the amount of folding is too large, problems such as paper jams may occur in the paper transport path after the paper leading edge folding means 6.

Hereinafter, the paper leading edge bending means 6, which is the main part of the present invention, will be explained with reference to the drawings. In addition, in the following figures, for the sake of clarity, the paper is shown to be conveyed from the left side in the figure, similar to those in FIGS. 1 to 3. Therefore, the folding direction of the leading edge of the paper is downward.
In short, the paper leading edge bending means 6 may be installed so that the direction in which the leading edge of the paper is folded is in the direction of the photosensitive drum 12, such as by turning the paper leading edge bending means 6 upside down or placing the photosensitive drum 12 on the lower side. .

4 and 5, the leading edge of the paper is placed on the photosensitive drum 1.
2 shows an embodiment of the means 6 for bending in two directions. As shown in FIG. 4, the paper 4 is conveyed to a guide 32 provided on the stay 30 of the paper leading end folding means 6. As shown in FIG. The fixed blade 34 is attached to the stay 30 or the side plate of the paper leading edge bending means 6. The tip of the fixed blade 34 is
As shown in FIG. 5, unlike a cutter, it is rounded. A bending blade 36 for bending the leading edge of the paper 4 is rotatably attached to the side plate. The paper 4 is guided between the fixed blade 34 and the folding blade 36, and is stopped by the lower blade of the folding blade 36. Thereafter, the folding blade 36 descends and the leading edge of the paper 4 is folded.

FIG. 6 shows the process in which the leading edge of the paper 4 is bent. As the paper 4 is conveyed, the leading edge of the paper 4 collides with the lower blade of the folding blade 36, and the paper 4 is stopped. Thereafter, the folding blade 36 descends, guides the leading edge of the paper 4 between the fixed blade 34 and the folding blade 36, and folds it by a folding amount L. The bending blade 36 is rotated by a reciprocating motion type or a rotary motion type.

FIG. 7 shows a control configuration for rotating the sheet leading edge bending means 6. As shown in FIG. The paper 4 is sent to the control device 4
The paper feed roller 44 is driven by the paper feed roller driving means 42 controlled by the paper feed roller 44 to be conveyed. The paper 4 is detected by the paper detection sensor 46 disposed just before the paper leading edge bending means 6.
The control device 40 judges this detection signal and outputs a drive signal to the bending blade driving means 48 to drive the bending blade 36. After a certain period of time, the control device 40 further drives the folding blade 36 to retract the paper 4.
is conveyed to the downstream conveyance path 50. After the paper 4 passes through the paper leading edge folding means 6, the folding blade 36 is controlled so as to stop again at a position where the leading edge of the next paper 4 is stopped by the lower blade.

As shown in FIG. 8, the bending amount L by the sheet leading edge bending means 6 is suitably 0.1 to 0.6 mm. When the bending amount L is 0.1 mm or less, the bending effect is insufficient and winding around the photosensitive drum 12 occurs. On the other hand, if the bending amount L is larger than 0.6 mm, troubles are likely to occur in the paper conveyance path or the stacker.

According to this embodiment, 0.1 mm to 0.6 m
The device that makes the fold m toward the photoreceptor is not effective for thick paper that does not wrap around the photoreceptor. Also, the leading edge of the paper is temporarily stopped by a stopper, and in that state, the leading edge of the paper is
Since the two-stage blade that bends 0.6 mm operates to act on the leading edge of the paper, there is no possibility of a malfunction such as bending the leading edge of the paper to a dimension greater than the specified size.

FIGS. 9 and 10 show the sheet leading edge bending means 6.
Another example is shown below. FIG. 9 is a diagram showing the control configuration of this example, and FIG. 10 is a diagram showing the operation process. As shown in these figures,
In this embodiment, the leading edge of the paper 4 conveyed by the paper feed roller 44 is detected by the paper detection sensor 46, and when the leading edge of the paper 4 protrudes by an amount L from the end surface of the fixed base 52, the reciprocating blade 54 is activated from above. Then, the L portion is bent from the end face of the fixed base 52, and then it is retracted upward again. This embodiment also provides the same effects as the embodiment shown in FIG.

In these embodiments, a separate corotron is placed on the back side of the transfer belt, a rubber roller with high electrical resistance is used to press the paper against the photoreceptor, or a bias voltage is applied to this rubber roller to attract the toner. By doing so, a clear image without any disturbance can be obtained.

[0022]

According to the present invention, it is possible to prevent paper from wrapping around a photosensitive drum, which is caused by sagging or curling of the edges of cut paper during cutting.

Furthermore, since no special means is required to separate the paper from the photosensitive drum, there is an effect of reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an electrophotographic apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a conventional phenomenon in which paper wraps around a photosensitive drum.

FIG. 3 is a diagram showing a conventional phenomenon in which paper wraps around a photosensitive drum.

FIG. 4 is a schematic configuration diagram showing a paper leading end folding means according to an embodiment of the present invention.

FIG. 5 is a schematic enlarged view of the paper leading edge folding portion in FIG. 4;

FIG. 6 is a diagram illustrating a process in which the leading edge of the paper is folded in this embodiment.

FIG. 7 is a control configuration diagram of a sheet leading edge bending means of the present embodiment.

FIG. 8 is a diagram showing the relationship between the bending length L of the leading edge of the paper, paper wrapping around the photosensitive drum, and paper conveyance jam.

FIG. 9 is a control configuration diagram of a paper leading end folding means in another embodiment of the present invention.

10 is a diagram showing a process in which the leading edge of the paper is folded in the embodiment of FIG. 9; FIG.

[Explanation of symbols]

2 Hopper 4 Paper 6 Paper leading edge bending means 8 Conveyance roller 10 Transfer belt 12 Photosensitive drum 14 Developing device 16 Transcription corotron 18 Fixing device 20 Unloading roller 22 Optical unit 24 Cleaner 26　Void layer 30 Stay 32 Information guide 34 Fixed blade 36 Bending blade 40 Control device 42 Paper feed roller drive means 44 Paper feed roller 46 Paper detection sensor 48 Bending blade drive means 50 Downstream conveyance path 52 Fixed stand 54 Reciprocating blade

Claims (12)

[Claims] 1. A paper feeding device that separates and feeds stacked sheets one by one, an endless transfer belt made of a dielectric material that electrostatically attracts and transports the sheets, and a pulley that drives the transfer belt. and at least one pulley for tensioning the transfer belt; a photoconductor that holds an electrostatic latent image corresponding to printing information and toner electrostatically attracted on the electrostatic latent image; and a toner image on the photoconductor. In an electrophotographic apparatus, the electrophotographic apparatus includes a transfer section that sandwiches and contacts the paper between the photoreceptor and the transfer belt in order to transfer the paper to the paper being conveyed by the transfer belt, the paper feeder and An electrophotographic apparatus, further comprising a means for slightly bending a leading end of the sheet of paper toward the photoreceptor, between the sheet of paper and the transfer section. 2. A paper feeding device that separates and feeds the stacked sheets one by one, an endless transfer belt made of a dielectric material that electrostatically attracts and transports the sheets, and a pulley that drives the transfer belt. and at least one pulley for tensioning the transfer belt; a photoconductor that holds an electrostatic latent image corresponding to printing information and toner electrostatically attracted on the electrostatic latent image; and a toner image on the photoconductor. In an electrophotographic apparatus, the electrophotographic apparatus includes a transfer section that sandwiches and contacts the paper between the photoreceptor and the transfer belt in order to transfer the paper to the paper being conveyed by the transfer belt, the paper feeder and A support part that supports the leading edge of the paper, a fixed part having a rounded corner that contacts the leading edge of the paper, and a fixed part that moves with a predetermined gap from the fixed part between the transfer part and the paper. An electrophotographic apparatus comprising: a moving part that bends the leading edge of the paper in a gap with the fixed part toward the photoreceptor; and paper leading edge bending means. 3. The electrophotographic apparatus according to claim 2, wherein the moving section includes an abutting section that abuts and stops the leading end of the conveyed sheet. 4. The electrophotographic apparatus according to claim 2, wherein the moving section rotates. 5. The electrophotographic apparatus according to claim 2, wherein the moving section reciprocates in a linear direction. 6. The electrophotographic apparatus according to claim 2, wherein the gap between the fixed part and the moving part is such that the bending length of the leading edge of the paper is 0.1 mm to 0.6 mm. Characteristic electrophotographic equipment. 7. The electrophotographic apparatus according to claim 1, further comprising a transfer corotron on the back side of the transfer belt. 8. The electrophotographic apparatus according to claim 1, further comprising a transfer corotron and a separation corotron on the back side of the transfer belt. 9. The electrophotographic apparatus according to claim 1, wherein the transfer section includes a rubber roller having high electrical resistance that transfers the toner image on the photoreceptor to the paper by pressing the paper against the photoreceptor. An electrophotographic device comprising: 10. The electrophotographic apparatus according to claim 1, wherein a bias voltage is applied to the transfer section to transfer the toner image on the photoreceptor to the paper by pressing the paper against the photoreceptor. An electrophotographic device characterized by having a rubber roller with high electrical resistance. 11. The stacked sheets are separated and fed one by one, and the sheets are electrostatically attracted and conveyed by an endless transfer belt made of a dielectric material, so that an electrostatic latent image corresponding to the printing information and the corresponding image are formed. At a transfer section where the paper is sandwiched between and in contact with the transfer belt and a photoconductor that holds toner electrostatically adsorbed on the electrostatic latent image, the toner image on the photoconductor is conveyed by the transfer belt. An electrophotographic device that transfers images onto paper that is
The method for preventing paper from wrapping around the photoreceptor of an electrophotographic apparatus, wherein the leading edge of the paper being conveyed to the transfer section is slightly bent in the direction of the photoreceptor. How to prevent it. 12. The method according to claim 11, wherein the bending length of the leading edge of the paper is 0.1 mm to 0.6 mm.
1. A method for preventing paper from wrapping around a photoreceptor of an electrophotographic device, characterized in that: