JPH06130800A - Image forming device - Google Patents

Abstract

PURPOSE:To form the image of high quality without distortion by always keeping form feeding speed constant. CONSTITUTION:A developing unit 15 is attachably/detachably fitted to a device case 1. Toner T is stuck to an electrostatic latent image on a photosensitive drum 11 to the developing unit 15. A recording paper P is fed between the photosensitive drum and a transfer unit 23 by the rotation of a feeding roller 22. A toner image on the photosensitive drum 11 is transferred on the recording paper P by the transfer unit 23. A cleaning brush 35 is formed by flocking fiber on a base member 36 and stuck/fixed to the bottom part of the toner case 16 of the developing unit 15 through the base member 36. In a state where the developing unit 15 is fitted to the device case 1, the top end of the fur of the cleaning brush 35 is brought into contact with the top end of the outer periphery of the driven roller 22b of the feeding roller 22. Paper powder, etc., stuck on the driven roller 22b are removed by the cleaning brush 35, accompanying with the rotation of the feeding roller 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which a sheet is fed between a photoconductor and a transfer unit and a toner image is formed on the sheet. The present invention relates to a feed roller for feeding into a transfer device.

[0002]

2. Description of the Related Art In this type of image forming apparatus, an exposing device forms an electrostatic latent image on a photosensitive drum as a photoconductor, and a toner is attached to the electrostatic latent image by a developing device. It is like this. Then, the sheet is fed by the rotation of a pair of feed rollers composed of a driving roller and a driven roller, and is fed between the photosensitive drum and the transfer device. In this state, the transfer device transfers the toner image on the photosensitive drum. Is transferred onto the paper.

[0003]

By the way, although the outer circumference of the feed roller is usually made of silicone rubber or the like,
Paper powder or the like adheres to the peripheral surface of the feed roller as the paper is transferred. Therefore, the frictional coefficient of the feed roller is lowered by the paper dust or the like, and slippage easily occurs between the feed roller and the paper. Then, there is a possibility that the feed roller may not be able to stably transport the paper at a predetermined transport speed. Therefore, in such a case, the paper cannot be fed between the photosensitive drum and the transfer device at a predetermined timing, the transfer position of the toner image on the paper is displaced from the predetermined position, or the transfer image is not transferred to the paper. There is a problem in that the quality of a transferred image may be deteriorated due to a state in which the image is expanded and contracted in the transport direction to be distorted.

The present invention has been made to solve the above problems, and an object of the present invention is to always maintain a constant sheet feeding speed and perform high-quality image formation without distortion. It is to provide an image forming apparatus capable of

[0005]

In order to achieve the above object, according to the present invention, a developing device is detachably attached to an apparatus case, and the developing device forms a toner image on a photoconductor and feeds it. In an image forming apparatus in which a sheet is fed between a photoconductor and a transfer unit by a roller and a toner image on the photoconductor is transferred onto the sheet by the transfer unit, the developing unit is attached on a feed roller. A brush is attached to remove paper dust and the like.

[0006]

Therefore, according to the present invention, as the feed roller rotates, the paper dust and the like adhering to the roller is removed by the brush. Therefore, the friction coefficient of the feed roller is not lowered by the attached paper dust and the slippage between the feed roller and the paper does not easily occur, and the paper is stably transported by the feed roller at a predetermined transfer speed. To be done. The brush is attached to the developing device, and the developing device is detachably attached to the apparatus case. Therefore, even if paper dust or the like is accumulated in the brush and the ability of the brush to remove the paper dust is reduced, the brush can be easily cleaned by removing the developing device from the apparatus case.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the device case 1 includes a substantially box-shaped lower case 2 having an open upper surface, and an upper case 4 mounted on the lower case 2 via a support shaft 3 so as to be openable and closable. It is configured. A pair of left and right support bodies 5 are provided on both inner sides of the lower case 2, and a pair of front and rear guide grooves 6 and 7 extending downward from the upper end side of the support body 5 are formed on the inner side surfaces thereof.

The frame 9 of the photosensitive drum unit 8 is in the form of a box that is long in the left and right, and support shafts 10 are formed so as to project from both ends. Then, the both support shafts 10 are inserted into the front guide groove 6 and are engaged with the bottom of the front guide groove 6, whereby the photosensitive drum unit 8 is detachably attached to the apparatus case 1. The photosensitive drum 11 as a photosensitive member is rotatably supported in the frame 9 of the photosensitive drum unit 8 at both ends of the rotary shaft, and a photoconductive film 12 is formed on the outer peripheral surface thereof.

As shown in FIGS. 1 and 2, the charger 13 is provided in the photosensitive drum unit 8 and uniformly charges the photoconductive film 12 to a predetermined potential. The exposure unit 14 is mounted in the upper case 4, and the upper case 4 is attached to the lower case 2.
The exposure device 14 irradiates the photosensitive drum 11 with light in a state where the photosensitive drum 1 is rotated in the upper closed position.
An electrostatic latent image having a predetermined potential is formed on 1.

The developing device 15 includes a toner case 16 for containing the toner T, a toner cartridge 17 detachably mounted on the toner case 16, and the photosensitive drum 1.
1 and a developing roller 18 disposed in a lower end opening portion in the toner case 16 so as to closely face the same. Engagement pins 16a are formed at both ends of the toner case 16,
By inserting both engagement pins 16a into the rear guide groove 7 of the support 5 and engaging with the bottom of the groove 7, the developing device 15
Is detachably attached to the device case 1. Then, a predetermined potential is applied to the toner T by the developing roller 18, and the toner T is attached to the electrostatic latent image based on the difference between the potential and the potential of the electrostatic latent image, and the electrostatic latent image is visualized. Be converted.

The paper feed cassette 19 is detachably attached to the lower part of the lower case 2, and a large number of recording papers P as papers are accommodated in the paper feed cassette 19 in a stacked state. Then, when the paper feed roller 20 is rotated, the recording papers P are sent out one by one from the paper feed cassette 19 and transferred to the lower part of the photosensitive drum 11 via the paper guide 21 and the pair of feed rollers 22. To be done. The feed roller 22 is composed of a drive roller 22a that can be positively rotated by a drive motor (not shown) and a driven roller 22b that is in contact with the drive roller 22a. Become.

The transfer unit 23 and the guide roller 24 are arranged so as to face the photosensitive drum 11 with a sheet transfer path interposed therebetween. Then, the recording paper P is brought into close contact with the photosensitive drum 11 by the guide roller 24, and a predetermined potential is applied to the close contact portion by the transfer device 23. Based on the difference between the potential and the potential of the toner image, The toner image is transferred onto the recording paper P.

The discharging lamp 25 is the photosensitive drum 11 after the transfer.
The outer peripheral surface of is irradiated with light to eliminate the electric charge. The cleaning brush 26 is disposed in the photosensitive drum unit 8,
The paper dust and the like adhering to the photosensitive drum 11 after the transfer is removed. The memory removal brush 27 made of a conductive brush is also arranged in the photosensitive drum unit 8 to scatter the toner T remaining on the photosensitive drum 11 after transfer and uniformly disperse the toner T on the photosensitive drum 11. Incidentally, the developing device 15 also performs a cleaning operation for collecting the residual toner T dispersed by the memory removing brush 27 by electrostatic attraction, in parallel with the developing operation.

The heat fixing device 28 is arranged on the paper feeding side of the photosensitive drum 11, and is provided with a heating roller 29 and a pressure roller 30 which comes into contact with the heating roller 29 with a paper transfer path interposed therebetween. Then, the recording paper P is the paper guide 3
The toner image on the recording paper P is heated and fixed by being fed between the heating roller 29 and the pressure roller 30 via 1. The recording paper P on which the image fixing is completed is discharged onto the paper discharge tray 34 via the paper guide 32 and the pair of guide rollers 33.

As shown in FIG. 1, the cleaning brush 35 is formed by implanting bristles on a base member 36, and the base member 36 holds the toner case 16 of the developing unit 15.
It is fixed to the bottom of the adhesive. Then, with the developing device 15 mounted in the apparatus case 1, the tips of the bristles of the cleaning brush 35 come into contact with the upper periphery of the driven roller 22b of the feed roller 22. Then, as the feed roller 22 rotates, the paper dust or the like adhering to the driven roller 22b is removed by the cleaning brush 35, and the removed paper dust or the like is collected in the cleaning brush 35.

In the image forming apparatus configured as described above, the recording paper P transferred from the paper feed cassette 19 side is rotated by the feed roller 22 and the photosensitive drum 11 is rotated.
And the guide roller 24. Then, as described above, the photosensitive drum 11 by the guide roller 24 is used.
A predetermined potential is applied by the transfer unit 23 to the contact portion between the recording paper P and the recording paper P, and the toner image on the photosensitive drum 11 is recorded on the recording paper P.
Transcribed on.

Further, along with this sheet transfer, the feed roller 2
Paper dust or the like of the recording paper P adheres to the peripheral surface of 2. However, in this embodiment, the cleaning brush 35 removes paper dust and the like adhering to the peripheral surface of the driven roller 22b when the feed roller 22 rotates.

The cleaning brush 3 is provided on the drive roller 22a side.
Since No. 5 is not provided, it seems that the paper dust and the like adhering to the peripheral surface of the drive roller 22a is not removed. However, if the paper dust or the like on the peripheral surface of the driven roller 22b is reliably removed by the cleaning brush 35, the paper dust or the like attached to the peripheral surface of the drive roller 22a is attached to the driven roller 22b that contacts the roller 22a. The paper dust or the like attached to the driven roller 22b is removed by the cleaning brush 35.
Therefore, as a result, the paper dust and the like adhering to the peripheral surface of the drive roller 22a is also removed. Therefore, if the cleaning brush 35 is provided on at least one of the rollers 22a and 22b, the paper dust and the like adhering to the peripheral surfaces of the rollers 22a and 22b can be sufficiently removed.

As described above, by removing the paper dust and the like on the feed roller 22 by the cleaning brush 35, the friction coefficient of the feed roller 22 is lowered and slippage occurs between the feed roller 22 and the recording paper P. The recording sheet P can be stably transported at a predetermined speed by the feed roller 22 without being easily improved. Therefore, unlike the above-described conventional case, the transfer image is transferred between the photosensitive drum 11 and the guide roller 24 at a different timing, or the transfer image is expanded and contracted in the sheet transfer direction to be distorted. It is possible to perform high-quality image formation without the possibility that the quality will deteriorate.

Further, in this embodiment, the developing unit 15 can be easily taken out from the apparatus case 1 by opening and rotating the upper case 4 from the lower case 2. Therefore, paper dust or the like collects inside the cleaning brush 35.
Even if the paper dust removing ability of the device is lowered, the paper dust accumulated in the cleaning brush 35 can be easily removed by removing the developing device 15 from the device case 1. Therefore, it is possible to prevent the possibility that the cleaning brush 35 has a reduced ability to remove the paper dust and the feed roller 22 cannot stably transfer the recording paper P.

The present invention is not limited to the above embodiments, but can be embodied in the following modes without departing from the spirit of the present invention. (1) The cleaning brush 35 is detachably attached to the developing device 15 so that the cleaning brush 35 can be easily replaced with a new one. (2) The cleaning brush 35 should be grounded in order to release static electricity. (3) The cleaning brush 35 is subjected to a non-charging process so that the cleaning brush 35 is not charged with static electricity.

[0022]

As described above in detail, according to the present invention, it is possible to keep the sheet feeding speed constant at all times, and it is possible to perform high quality image formation without distortion. To do.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view showing an embodiment of an image forming apparatus embodying the present invention.

FIG. 2 is a cross-sectional view showing a mounting state of a photosensitive drum unit and a developing device on a support.

[Explanation of symbols]

1 ... Device case, 2 ... Lower case, 4 ... Upper case, 1
DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum as a photoconductor, 15 ... Developing device, 16 ...
Toner case, 22 ... Feed roller, 22a ... Drive roller, 22b ... Followed roller, 23 ... Transfer device, 35 ... Cleaning brush, P ... Recording paper.

Claims (1)

[Claims] 1. A developing device is detachably attached to an apparatus case, a toner image is formed on the photoconductor by the developing device, and a paper is sent between a photoconductor and a transfer device by a feed roller to transfer the image. An image forming apparatus in which a toner image on a photoconductor is transferred onto a sheet by a developing device, wherein the developing device is provided with a brush for removing paper dust and the like adhering to the feed roller.