JPH0687181B2 - Transfer device in electrophotographic device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transfer device in an electrophotographic apparatus.

2. Description of the Related Art Conventionally, in this type, the electrostatic latent image is formed on the outer periphery of the photoconductor by the electrostatic latent image forming means, and the electrostatic latent image is developed by the developing device, and the polarity of the electric charge of the toner is changed. The toner image on the photoconductor is transferred onto a sheet by an electric field generated by applying voltages of different polarities to the transfer charger, and the toner image on the sheet is fixed by a fixing unit. The paper feed path for guiding the paper between the photoconductor and the transfer charger is formed with the pair of guide plates facing each other. However, since the thickness of the paper differs depending on the paper quality, two paper guides are provided. The plates are arranged facing each other with some allowance in the facing distance.

Problems to be Solved by the Invention However, since the paper is attracted by the transfer charger, thin paper is easily separated from the outer peripheral surface of the photoconductor. In addition, since the electric field is applied from the transfer charger to the paper over a wide range, the transfer range from the photoconductor to the paper is widened. As a result, the sheet is separated from the outer peripheral surface of the photoconductor as the distance to the transfer charger becomes longer. In this way, when the space between the outer periphery of the photoconductor and the surface of the paper is opened, the transfer position of the toner on the photoconductor to the paper is displaced. Therefore, it is impossible to print clearly.

Means for Solving the Problems A rotatable photoconductor, an electrostatic latent image forming means for forming an electrostatic latent image on the outer periphery of the photoconductor, a developing device for developing the electrostatic latent image, and the photoconductor. A transfer charger for transferring the toner image of the body to a sheet, a fixing unit for fixing the toner image transferred on the sheet, a sheet feeding path for guiding the sheet between the photoconductor and the transfer charger, In an electrophotographic apparatus having a transport path for transporting a sheet from the transfer charger to the fixing unit, a movable body that is urged in a direction away from the transfer charger between an outlet of the sheet feed path and the transfer charger. Is rotatably provided, and a supporting roller that is positioned above the transfer path on one side of the sheet feeding path and elastically presses the sheet toward the photoconductor is rotatably bonded to the upper portion of the movable body. The transfer chain A receiving portion that is pressed against the bottom surface of the ear is fixedly provided on the movable body.

Therefore, the electrostatic latent image forming means forms an electrostatic latent image on the outer periphery of the photoconductor, and the electrostatic latent image is developed by the developing device.
This developed toner image is transferred to the paper by the transfer charger, and the toner image on the paper is fixed by the fixing unit.
The paper is brought close to the outer periphery of the photoconductor by a supporting roller near the transfer charger, and the range of the electric field generated by applying a voltage to the transfer charger is limited by the supporting roller so that the photoconductor and the transfer charger face each other. The transfer action is performed at a portion, that is, a portion where the paper sheet approaches the photoconductor, thereby preventing the shift of the transfer position of the toner image of the photoconductor on the paper sheet. Further, when the transfer charger is removed upward, the receiving portion is released to the bottom of the transfer charger, so that the movable body is separated from the transfer charger by the urging force, and thus the transfer charger is removed without interfering with the supporting roller. It becomes possible.

Embodiment An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a rotatable photoconductor, and a charging charger 2 for charging the outer peripheral surface of the photoconductor 1 and a photoconductor 1 are provided on the outer periphery of the photoconductor 1.
Electrostatic latent image forming means 4 including an exposing device 3 for scanning a laser beam on the outer peripheral surface of the sheet, and a developing device 5 for developing the electrostatic latent image.
A transfer charger 6 for transferring the toner image on the photoconductor 1 onto the sheet 9, a cleaning unit 7 for wiping off the residual toner on the photoconductor 1, and a charge eliminating unit 8 for erasing the electrostatic latent image on the photoconductor 1. And are provided.

Next, a paper feed cassette 10 for accommodating the paper 9 in a stacked state
And a paper feed roller 11 for taking out the papers 9 in the paper feed cassette 10 one by one, and the transfer charger 6 for the papers 9
And a sheet feeding roller 13 located on both sides of the sheet feeding path 12, and a conveying path 1 for guiding the sheet 9 from the transfer charger 6 to a fixing roller 14 which is a fixing unit.
5,16 and are provided. Further, a paper transport roller 17 is provided on one side of the transport path 15. Further, a pair of left and right peeling claws 18 whose front ends are inserted into annular grooves (not shown) formed at both ends of the photoconductor 1 are provided.

The paper feed path 12 is formed by a pair of guide plates 19 and 20 opposed to each other, and a space is provided between the guide plates 19 and 20 so that the thickest paper can be smoothly fed.

Next, a movable body 22 biased by a spring 21 in a direction away from the transfer charger 6 is rotatably held by a support shaft 23 between the outlet of the paper feed path 12 and the transfer charger 6. The movable body 22 is composed of a pair of left and right arms 24 held by a support shaft 23, and an arm 27 urged clockwise by a spring 25 and rotatably held at the upper end of the arm 23 by a support shaft 26. Both ends of a supporting roller 28 located above one side of the transfer charger 6 on the sheet feeding path 12 side are rotatably supported by these arms 27 and face the lower part of the supporting roller 28. Both ends of the receiving plate 29 are fixed. The support roller 28 and the receiving plate 29 are horizontally long along the photoconductor 1. Both ends of a leaf spring 31 having a receiving portion 30 pressed against the bottom surface of the transfer charger 6 are fixed to the left and right arms 24. Further, the stopper 32 that comes into contact with the arm 24 is formed integrally with the member that forms the transport path 16. Further, a sheet guide piece 33 projecting from the other side of the transfer charger 6 toward the central portion is provided on the transfer charger 6.

The casing of the electrophotographic apparatus (not shown) is formed by connecting an upper case and a lower case so as to be vertically rotatable. Then, the photoconductor 1, the electrostatic latent image forming unit 4, the developing device 5, the peeling claw 18, the cleaning unit 7, and the charge eliminating unit 8
The guide plate 19 and the guide plate 19 are held in the upper case, and the transfer charger 6, the fixing roller 14, the conveying paths 15 and 16, the paper conveying roller 17, the paper feeding roller 11, the guide plate 20, and the paper feeding cassette 10 are held.
Is the one held in the lower case.

In such a configuration, in the process of rotating the photoconductor 1 once, first, the outer peripheral surface of the photoconductor 1 is charged by the charging charger 2, and an electrostatic latent image is formed by scanning the charged portion with a laser beam from the exposure device 3. Then, the electrostatic latent image is developed by the developing device 5. On the other hand, the paper 9 of the paper feed cassette 10 is pulled out by the paper feed roller 11, and then is fed between the photoconductor 1 and the transfer charger 6 by the paper feed roller 13. Therefore, the transfer charger 6 applies a negative voltage to the toner image having a positive charge on the photosensitive member 1 on the sheet 9 to transfer the toner image.
Transfer to. Then, the paper 9 is attached to the photosensitive member 1 by the peeling claw 18.
It is peeled from and is transported along the transport paths 15 and 16. Subsequently, the fixing roller 14 fixes the toner image on the sheet 9 and discharges it to the outside.

Printing is performed on the paper 9 as described above, but since the receiving portion 30 receives a pressing force from the bottom of the transfer charger 6, the arm
24 is urged counterclockwise against the force of the spring and abuts on the stopper 32 to set the stop position. Then, in this state, the sheet 9 is pressed against the outer peripheral surface of the photoconductor 1 by the supporting roller 28. At this time, if the paper 9 is thick, the spring 25 is bent and the supporting roller 28 retracts together with the arm 27, so that the paper 9 is not pressed against the photoconductor 1 too much. Therefore, the surface of the sheet 9 can be brought close to the outer peripheral surface of the photoconductor 1. Further, the paper 9 is separated from the outer peripheral surface of the photoconductor 1 as it is farther from the center of the transfer charger 6, but the range of the electric field generated by applying a voltage to the transfer charger 6 is supported as shown in FIG. The roller 28 and the paper guide piece 33 restrict the rotation angle to a narrow range of θ. That is,
It is possible to perform transfer at a portion where the paper 9 can be brought close to the outer peripheral surface of the photoconductor 1, and thereby to prevent deviation of the transfer position of the toner image of the photoconductor 1 on the paper 9 and perform clear printing. You can

For maintenance, etc., the upper case is rotated upward to open the upper space of the transfer charger 6. When the paper 9 is jammed in the paper feed path 12 or the transport paths 15 and 16, the paper 9 is taken out in this state. When the transfer charger 6 is removed upward, the receiving portion 30 is released from the bottom of the transfer charger 6, so that the movable body 22 is rotated by the force of the spring 21 in the direction away from the transfer charger 6 about the support shaft 23 as a fulcrum. . Therefore, when the transfer charger 6 is removed, the supporting roller 28 can be automatically retracted from the upper side of the transfer charger 6 to the side. Toner may be spilled from the photoconductor 1 or the paper 9, but in this case, the receiving plate 29 can receive the toner.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, the paper can be brought close to the outer periphery of the photoconductor by the supporting roller in the vicinity of the transfer charge, and the electric field generated by applying a voltage to the transfer charge can be reduced. The range is limited by the supporting roller, and the copying action can be performed at the portion where the photoconductor and the transfer charger face each other, that is, the portion where the paper approaches the photoconductor, whereby the toner image of the photoconductor on the paper is obtained. The transfer position can be prevented from shifting, and a supporting roller is located above the transfer charger.However, when the transfer charger is removed upward, the receiving part is released to the bottom of the transfer charger, so a movable body is attached. Use the force to move it away from the transfer charger, and remove it without interfering with the support rollers. It has the effect of being able to

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a partially enlarged side view, and FIG. 2 is a side view showing the entire structure with a part thereof being sectioned. DESCRIPTION OF SYMBOLS 1 ... Photosensitive member, 4 ... Electrostatic latent image forming means, 5 ... Developing device, 6 ... Transfer charger, 9 ... Paper, 12 ... Paper feeding passage, 14 ... Fixing roller (fixing section), 22 …… Movable body, 28…
… Supporting rollers, 30 …… Receiving part

Claims (1)

[Claims] 1. A rotatable photoconductor, an electrostatic latent image forming means for forming an electrostatic latent image on the outer periphery of the photoconductor, a developing device for developing the electrostatic latent image, and toner for the photoconductor. A transfer charger for transferring an image onto a sheet; a fixing unit for fixing the toner image transferred on the sheet; a paper feed path for guiding the sheet between the photoconductor and the transfer charger; In an electrophotographic apparatus having a transport path for transporting from the transfer charger to the fixing unit, a movable body urged in a direction away from the transfer charger is freely rotatable between an outlet of the paper feed path and the transfer charger. A transfer roller, which is provided on one side of the copying path on the paper feed path side of the copy charger, and which elastically presses the paper toward the photoconductor, is rotatably mounted on the movable body. Press on the bottom of the charger Transfer apparatus in an electrophotographic apparatus, wherein a receiving portion fixedly provided on the movable body to be.