JPH06234255A - Electrophotographic apparatus - Google Patents

Abstract

PURPOSE:To correct at least the warpage of paper by taking a measure for positioning a pressure fixing part constituted by bringing a pair of freely reversibly rotatable pressure rollers having the length corresponding to the width of paper to a pressure contact state on the side of the paper feed part of a transcription part to arrange the same to a paper transfer passage. CONSTITUTION:At least, an electrostatic latent image forming part 8, a developing part and a transcription part 10 are respectively arranged around a photosensitive element 5. A paper feed part 16 is arranged to one end of the paper transfer passage 14 passing through the transcription part 10 a temporary stacker 17 is connected to the other end of the paper transfer passage 14. Further, a pressure fixing part 20 constituted by bringing a pair of freely reversibly rotatable pressure rollers 21, 22 having the length corresponding to the width of paper to a pressure contact state is positioned on the side of the paper feed part 16 of the transcription part 10 to be arranged to the paper transfer passage 14. A plurality of paper feed parts 24, 25 driven from the paper feed part 16 toward the temporary stacker 17 at the time paper feed and driven in the reverse direction at the time of printing are arranged to at least the temporary stacker 17. By this constitution, at least the pressure fixing part 20 is utilized to correct the warpage of the paper.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic apparatus.

[0002]

2. Description of the Related Art Conventionally, in order to remove moisture from a paper supplied for printing, there is a heater in which heat is applied to the paper during the paper feeding process. However, the warp or waviness of the paper is corrected. It is not possible. In addition, JP-A-4-1912
As described in Japanese Patent Laid-Open No. 28-28, there is an invention in which the paper is prevented from being generated in the image forming unit by conveying the paper while pressing it with a pressure roller.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The invention described in Japanese Patent Publication No. 8 is an invention aimed at preventing the generation of paper dust. However, since the paper is pressed by the pressing roller during the paper feeding, the operation of flattening the paper can also be obtained. It is considered to be a thing. However, there is a problem that the number of parts increases because a pair of pressure rollers is provided only for the purpose of simply pressing the paper.

[0004]

SUMMARY OF THE INVENTION According to the present invention, at least an electrostatic latent image forming section, a developing section and a transfer section are arranged around a photoconductor, and one end of a sheet conveyance path passing through the transfer section is provided. A pressure fixing unit, which is provided with a paper unit, is connected to a temporary stacker at the other end, and has a pair of forward and reverse rotatable pressure rollers having a length corresponding to the width of the paper, is brought into pressure contact with each other. At least the temporary stacker is provided with a paper feed unit that is located on the paper unit side and is provided in the paper conveyance path, and that is driven from the paper feed unit toward the temporary stacker during paper feeding and in the reverse direction during printing.

[0005]

According to the present invention, the sheet can be flattened by the pressure fixing section in the process of conveying the sheet from the sheet feeding section to the temporary stacker. Further, in the process of reversing the paper feeding unit to return the paper from the temporary stacker, the image on the photoconductor can be transferred to the paper by the transfer unit, and the image transferred to the paper can be fixed by the pressure fixing unit. Furthermore, since the pressure fixing unit can be used to correct the warp and waviness of the paper, the number of parts can be reduced, and further,
Since a heater is not required for fixing, it is possible to save electric power.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 is a housing. The housing 1 is divided into two parts in the vertical direction and has an upper part that can be opened and closed, and has a pressing part 3 that releases the cover switch 2 and switches the cover switch 2 on when the upper part is opened. A paper discharge tray 4 is provided above the housing 1, and a photoconductor 5 is rotatably provided inside. Around the photoconductor 5, an electrostatic latent image forming unit 8 including a charger 6 and an exposing unit 7, a developing unit 9,
A transfer unit 10, a charge eliminating unit 11, a cleaning unit 12,
The static eliminator 13 is sequentially arranged counterclockwise.

A paper feed roller 16 is provided at one end of the paper feed path 14 that passes through the transfer unit 10 and the charge removal unit 11 as a paper feed unit for feeding the papers in the paper feed cassette 15 one by one. A temporary stacker 17 is connected to the other end of the paper transport path 14. A paper discharge path 18 is provided between the transfer unit 10 and the paper feed roller 16 and extends from the paper transport path 14 toward the paper discharge tray 4. The paper discharge path 18 and the paper transport path 18 are provided. A conveyance direction switching member 19 is provided at a branch point with respect to 14 so as to be vertically displaceable. A pressure fixing unit 20 is provided between the transport direction switching member 19 and the charge eliminating unit 11. The pressure fixing unit 20 includes a pair of pressure rollers 2 made of metal and having a length corresponding to the width of the paper and being rotatable in the forward and reverse directions.
The first and second members 22 and 22 are formed by press-contacting each other with their axes slightly inclined. Between the pressure fixing unit 20 and the paper feed roller 16, a carrying roller 23 that carries the paper fed from the paper feeding roller 16 only to the left is disposed. Further, reversing rollers 24 and 25, which are driven from the paper feed roller 16 toward the temporary stacker 17 at the time of paper feeding and are driven in the opposite direction at the time of printing, are provided at the temporary stacker 17 and one end of the paper transport path 14. The paper discharge path 18 is provided with a paper discharge roller 26. The housing 1 is provided with a DC power supply 27 and a heat radiation fan 28.

In such a structure, the conveyance direction switching member 19 is driven in the clockwise direction to connect the paper feed cassette 15 and the paper conveyance path 14 prior to the printing operation. In this state, the paper in the paper feed cassette 15 is pulled out by the paper feed roller 16, and the conveyance roller 23, the pressure roller 21,
22 and the reversing rollers 24 and 25 provide a temporary stacker 1
Sent to 7. At this time, the paper is pressed by the pressure rollers 21 and 22.
The sheet is pressed and stretched flat, thereby correcting the warp and waviness of the sheet.

On the other hand, the photoconductor 5 is driven counterclockwise,
In the process, the charger 6 is uniformly charged, and the charged portion is scanned with laser light modulated according to an image signal from the exposure device 7 to form an electrostatic latent image, and the electrostatic latent image is developed. Developed by part 9. In synchronization with this operation, the reversing rollers 24 and 25 and the pressure rollers 21 and 22 of the pressure fixing unit 20 are driven in the opposite directions, and the paper of the temporary stacker 17 is supplied to the lower portion of the photoconductor 5. The image on the photoconductor 5 is transferred to the paper by the transfer unit 10, and the paper after the transfer is the static elimination unit 1.
The charge is removed by 1 to be peeled off from the photoconductor 5, and the transfer image is fixed by the pressure fixing unit 20. In this case, since a heater is not required for fixing, power can be saved. By the time the fixing starts, the conveyance direction switching member 19 is driven in the counterclockwise direction to connect the paper conveyance path 14 and the discharge path 18, so that the sheet passing through the pressure fixing section 20 is discharged to the discharge path 18. Then, the sheet is discharged to the sheet discharge tray 4. After the transfer, the residual toner is wiped off from the photoconductor 5 by the cleaning unit 12, and then the charge is removed by the charge removing unit 13.

In the above embodiment, the description has been given of the case where the transferred sheet is discharged to the sheet discharge tray 4 via the sheet discharge path 18, but it may be returned to the sheet feed cassette 15.
In this case, the transport roller 23 is used depending on the transport direction of the paper.
Is selectively rotated in the forward or reverse direction. In this case, a paper discharge roller for discharging the returned paper to the outside of the paper feed cassette 15 may be provided if necessary.

[0011]

As described above, the present invention has a length corresponding to the width of the sheet by providing the sheet feeding section at one end of the sheet conveying path passing through the transfer section and connecting the temporary stacker at the other end. A pressure fixing unit consisting of a pair of pressure rollers that rotate freely in the forward and reverse directions is pressed against each other and is located in the paper transport path on the paper feed unit side of the transfer unit. Since at least the temporary stacker is provided with a paper feeding unit that is driven and driven in the reverse direction during printing, the paper can be flattened by the pressure fixing unit in the process of conveying the paper from the paper feeding unit to the temporary stacker. In the process of reversing the paper feed unit and returning the paper from the temporary stacker, the transfer unit can transfer the image on the photoconductor to the paper and the pressure fixing unit can fix the image transferred to the paper. Fixed Since the warp and corrugation of the paper can be corrected by using the parts, it is possible to reduce the number of parts, and further, since a heater is not required for fixing, power can be saved. And so on.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view schematically showing an electrophotographic apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 5 Photoconductor 8 Electrostatic Latent Image Forming Section 9 Developing Section 10 Transfer Section 14 Paper Conveying Path 16 Paper Feeding Section 17 Temporary Stacker 20 Pressure Fixing Section 21, 22 Pressure Roller 24, 25 Paper Feeding Section

Claims (1)

[Claims] 1. At least an electrostatic latent image forming section, a developing section and a transfer section are arranged around a photoconductor, and a paper feed section is provided at one end of a paper conveyance path passing through the transfer section and at the other end. A temporary fixing stacker is connected, and a pressure fixing unit formed by pressing a pair of forward and reverse rotatable pressure rollers having a length corresponding to the width of the paper into pressure contact with each other is located on the paper feeding unit side of the transfer unit, An electrophotographic apparatus, wherein at least the temporary stacker is provided with a paper feed unit that is provided in a paper transport path and is driven from the paper feed unit toward the temporary stacker during paper feeding and is driven in the reverse direction during printing.