JPH05257346A - Paper feeding guide device - Google Patents

Abstract

PURPOSE:To obtain the paper feeding guide device where recording paper can be proceeded toward a photosensitive drum with stability. CONSTITUTION:The paper feeding guide device 21 consists of a pair of second paper feeding rolls 13, the paper feeding guide member 22 adjacent to the rolls on the left side, each supporting parts 25 and 26 in two places supporting the paper feeding guide member 22, a shaft support 26a supporting the shaft of the paper feeding guide member 22, a shaft supporting screw 23 and an energizing spring 24. A slit 22f is provided in a back side bent part 22d which is one of the bent parts of the paper feeding guide member 22 and when the paper feeding guide member 22 is attached to each supporting parts 25 and 26 by the shaft support 26a and a shaft supporting screw 23, a space D is secured between a periphery surface of a photosensitive drum 3 and the paper feeding guide member 22 by the effect of the slit 22f and the energizing spring 24 even if the paper feeding guide member 22 is deformed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed guide device for feeding recording paper to a photosensitive drum mounted in an image forming apparatus such as a copying machine or an image scanner.

[0002]

2. Description of the Related Art Generally, an electrophotographic image forming apparatus such as a copying machine or an image scanner comprises a platen on which a document is placed, a document irradiation lamp which reciprocates below the platen, a reflection mirror, and a fixed projection lens and a reflection mirror. A photosensitive drum that is endlessly rotated by a scanning optical system and a band electrode that are charged with a predetermined potential, and toner is applied to the electrostatic latent image formed on the surface of the photosensitive drum by the scanning optical system. A developing device for developing the toner image, a transfer electrode for transferring a toner image onto a recording paper surface which is a transfer material conveyed below the surface of the photosensitive drum, a separation electrode and a removing electrode, and the recording paper surface. The fixing device fixes the toner image transferred onto the surface of the photosensitive member, and the cleaning device removes the toner and paper dust remaining on the surface of the photosensitive member after the transfer. In a recent popular type copying machine, for example, a process cartridge in which a cartridge in which a belt electrode, a photosensitive drum, a cleaning device and the like are unitized and a developer cartridge which can be separated and connected to the cartridge are combined into one is used as an image forming apparatus. It's quite compact because it's removable.

Further, the toner collected by the cleaning device is supplied to the developing device by the recycling device and is reused.

[0004]

Generally, the recording paper carried out from the paper feed cassette is accurately conveyed to the surface of the photoconductor drum by a timing roller and a paper feed guide member which are provided in front of the photoconductor drum, and is always in good condition. The toner image is transferred. The longitudinal direction of the photosensitive drum is, for example, B
The four-size recording paper has a length capable of recording an image in the width direction, and the paper feed guide member has the same length.

In order to transfer a good toner image over the entire area of the recording paper, the distance between the peripheral surface of the photosensitive drum and the leading end of the paper feed guide member that allows the recording paper to enter the peripheral surface of the photosensitive drum. Is one of the conditions to maintain high accuracy within, for example, 1.5 mm ± 0.1 mm. However, in order to process the parts such as the paper feed guide member, the frame of the image forming apparatus supporting the same and the casing of the photoconductor drum, and the mutual assembly within the predetermined processing accuracy, the length is long and the area is large. There is a problem such as processing distortion, which requires a very troublesome work, and inevitably causes variations in accuracy. If the positions of the peripheral surface of the photosensitive drum and the paper feed guide member do not reach the predetermined accuracy, the recording paper that enters toward the photosensitive drum flaps and the transferred toner image is disturbed. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a paper feed guide device capable of accurately attaching a paper feed guide member to a photosensitive drum.

[0006]

The purpose of this invention is to feed a sheet, which is carried out from the sheet storage section by the first carrying means, to the photosensitive drum by the second carrying means and the paper feed guide member. In the guide device, the paper feed guide member has two fulcrums pivotally supported by a pair of supporting portions provided in the image forming apparatus, and a paper feed formed in the sheet conveying direction with reference to the fulcrums. This is achieved by a paper feed guide device characterized in that one end of the guide member is provided with an elongated hole at the fulcrum of the paper feed guide member having a positioning surface for positioning the photosensitive drum at the tip end portion of the guide member.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is a side view showing the structure of the paper feed guide device of FIG. 1, a perspective view showing the shape of the paper feed guide member of FIG. 2, and a side showing the structure of the image forming device of FIG. A cross-sectional view will be described. However, the present invention is not limited to this embodiment.

As shown in FIG. 3, an electrophotographic image forming apparatus 18 is provided.
A platen glass P for placing a document M is provided on the upper surface of the main body 1, and a scanning optical system 2 is provided below the platen glass P in the main body 1. The scanning optical system 2 includes a reciprocating document irradiation lamp 2a, a first mirror 2b, second and third mirrors 2c forming a V shape, and a fixed lens 2.
d and the fourth mirror 2e. A photosensitive drum 3 is rotatably provided in the direction of the arrow at the center of the inside of the main body 1, and a belt electrode 4 for uniformly charging the photosensitive body 3a along the rotation direction is provided around the photosensitive drum 3, and a toner replenishing device. 5, a developing device 6 in which the toner is replenished with toner and a developing sleeve 6a is built in, a transfer electrode 7, a separation electrode 8, a charge eliminating electrode 9, and a cleaning device 10 are sequentially arranged. Paper cassette 11,1
Two types of recording papers having different sizes are stored in 1'and set in the main body 1. 12 is a paper cassette 11
Is a first paper feed roller that feeds the recording paper stored in to a standby position before the second supply roller 13, and is a roller 12a that is rotated via a belt to prevent double feeding of the recording paper.
12a and a stop roller (also referred to as a separating roller) 12b. Reference numeral 13 is an appropriate timing so that the recording paper fed by the first paper feed roller 12 is temporarily stopped at the standby position, and then the front end of the visible image on the photoconductor 3a and the front end of the recording paper are aligned at the transfer position. The second paper feed roller 14 that feeds paper again toward the transfer position at 14 is a guide plate for guiding the recording paper fed by the first paper feed roller 12 to the position of the second paper feed roller 13, It is opened and closed by operating a lever (not shown) so that the jammed paper can be taken out by inserting a hand. Reference numeral 15 is a conveying device that conveys the recording paper after transfer to a fixing position, and the fixing device 16 is a heating roller.
16a and pressure roller 16b. Reference numeral 17 denotes a paper discharge roller that discharges the recording paper after fixing to the outside of the main body.

As shown in the figure, a first cartridge 20 containing the belt electrode 4, the photosensitive drum 3, and the cleaning device 10, a second cartridge in which the developing device 6 and the toner replenishing device 5 are unitized. Process cartridge which is divided into two parts such as 30 so that they can be separated from each other and combined.
40 is detachably attached to the image forming apparatus 18.

When the copy button is operated in the above apparatus, the original M on the platen glass P is exposed and scanned by the scanning optical system 2, and an electrostatic latent image of the original M is formed on the photoconductor 3a of the photoconductor drum 3. It This electrostatic latent image is made into a visible image by the developing device 6, and this visible image is the paper feeding cassette of the main body 1.
Transfer electrode 7 is applied to recording paper fed from either 11 or 11 '.
Transcribed by After the transfer, the recording paper is separated from the photoconductor 3a by the separation electrode 8 and is fixed by the conveyance device 15 to the fixing device 16
The sheet is conveyed to the sheet, is fixed there, and is ejected by the sheet ejection roller 17. In this way, desired toner images are successively recorded on the recording paper surface.

The paper feed guide device for admitting the recording paper to the peripheral surface of the photosensitive drum of the present invention is constructed as follows.

As shown in FIG. 1, the paper feed guide device 21 is a second
Adjacent to the left side of the pair of paper feed rollers 13, a paper feed guide member 22 for advancing the recording paper toward the peripheral surface of the photosensitive drum 3
And a main body 1 that rotatably supports the paper feed guide member 22.
Front support portion 25 and rear support portion 26 provided on the rear side, support shaft 26a and front support portion 25 provided on the rear support portion 26, front bent portion
22c Support shaft screw 23 mounted on both sides, and paper feed guide member
22 is urged clockwise and the drum case of the photoconductor drum 3
And a biasing spring 24 that abuts against the reference surface 33. The paper feed guide member 22 is a plate-shaped member that has been pressed as shown in FIGS. 1 and 2, and the top surface of the paper feed guide member 22 is flat along the longitudinal direction (the direction perpendicular to the paper surface of FIG. 1).
As shown in the drawing, the left end 22b of the drum case 33 is bent at a predetermined angle, and its upper surface is in contact with reference surfaces 33a provided at both longitudinal ends of the drum case 33.

Both ends of the paper feed guide member 22 in the longitudinal direction are symmetrically bent forward and downward at a right angle, and a front bent portion 22c is formed.
The screw hole 22e into which the spindle screw 23 is screwed in
On the other hand, an elongated hole 22f is provided at a position symmetrical to the screw hole 22e on the back side bent portion 22d. A protrusion 22h is symmetrically formed at the lower left end of each bent portion 22c, 22d, and a biasing spring 24 is fitted to each protrusion 22h as shown in FIG. Therefore, the upper end of the urging spring 24 contacts the paper feed guide member 22 and the lower end of the urging spring 24 contacts the frame of the main body 1 to urge the same. In the longitudinal direction of the frame 1a of the main body 1 of the image forming apparatus 18 (perpendicular to the paper surface), a front support portion 25 and a back support portion 26 that support the paper feed guide member 22 are erected at right angles. A hole 25a is provided at a predetermined position of the front side support portion 25, and the support screw 23
The stepped part of is fitted. Also the back side support
A support shaft 26a projecting toward the front side support portion 25 is integrally formed with the hole 26a at a position symmetrical to the hole 25a, and the support shaft 26a is fitted into the long hole 22f of the paper feed guide member 22. There is. The front and rear supporting portions 25 and 26 may be integrally formed with the frame of the main body 1, or the front and rear supporting portions 25 and 26 may be formed on a substrate molded of synthetic resin. 26
Also, it does not matter if the integrally molded member including the support shaft 26a is attached to the frame 1a of the main body 1.

The sheet feeding guide member 22 formed in this manner has the front side bent portion 22c positioned inside the front side support portion 25 after the long hole 22f is fitted to the support shaft 26a of the back side support portion 26. By fitting the flat portion of the stepped portion of the support shaft screw 23 into the hole 25a and setting it in the screw hole 22e of the front side bent portion 22c of the paper feed guide member 22, the paper feed guide member 22 is provided with each projection 22h.
Via the elastic force of the biasing spring 24 attached to
The upper surface of 22b is pressed against the reference surface 33a of the drum case 33 with a predetermined pressing force. The long hole 22f is a round hole and 25a may be replaced with a long hole.

In this way, the distance D between the peripheral surface of the photosensitive drum 3 and the front end portion 22b of the paper feed guide member 22, that is, the distance at which the recording paper enters the photosensitive drum 3 is set. Although not described, an upper guide member is provided on the upper side facing the paper feed guide member 22 at a predetermined interval, and the recording paper passes between the paper feed guide member 22 and the upper guide member to expose the light. It is designed to enter the body drum 3.

Then, for example, the front end portion 22 of the paper feed guide member 22.
When the front side and the back side of b are deformed, the long hole 22f slides the support shaft 26a according to the deformation amount to absorb the error, and the upper surface of the tip end 22b is pressed equally to the reference surface of the drum case 33. A predetermined distance D is secured over the entire area in the longitudinal direction between the peripheral surface of the photosensitive drum 3 and the tip portion 22b.

Further, even when the dimensions of the supporting portions 25 and 26 for supporting the paper feed guide member 22 are changed, the slot 22f is formed.
Of course, it will be modified by. As described above, the paper feed guide member 22 is very easily attached to the peripheral surface of the photosensitive drum 3.
Since it can be accurately mounted with a predetermined interval provided over the entire longitudinal direction, the assembling work becomes very easy and the second
The recording paper conveyed from the paper feed roller 13 in the direction of the arrow smoothly enters the peripheral surface of the photosensitive drum 3 and a good toner image is transferred. The elongated hole 22f is not limited to the back side bent portion 22d of the paper feed guide member 22 and may be provided with a position different from that of the screw hole 22e of the front side bent portion 22c. The position of the hole 25a is changed to the back side support portion 26 in the front side support portion 25.

The direction of the long hole 22f may be appropriately set in accordance with the deformation characteristics of the paper feed guide member 22 and other members.

[0019]

According to the present invention, since the paper feed guide device described above can accurately and extremely easily secure the predetermined interval with respect to the photoconductor drum even if the paper feed guide member is deformed. Processing and assembly become very easy and the recording paper stably enters toward the photosensitive drum, so that a good toner image is always transferred.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of a paper feed guide device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a shape and a mounting state of a paper feed guide member according to an embodiment of the present invention.

FIG. 3 is a side sectional view showing the configuration of the image forming apparatus.

[Explanation of symbols]

 3 Photoreceptor Drum 13 Second Paper Feed Roller Pair 18 Image Forming Device 21 Paper Feed Guide Device 22 Paper Feed Guide Member 22b Tip 22c Front Bend 22d Back Bend 22f Long Hole 23 Spindle Screw 24 Energizing Spring 25 Front support 26 Back support 26a Spindle 33 Drum case

Claims (1)

[Claims] 1. A sheet feeding guide device of an image forming apparatus, which conveys a sheet carried out from a sheet storage section by a first conveying means to a photosensitive drum by a second conveying means and a sheet feeding guide member. The guide member has two fulcrums pivotally supported by a pair of supporting portions provided in the image forming apparatus, and is exposed to the leading end of the paper feed guide member formed in the sheet conveying direction with reference to the fulcrums. A sheet feeding guide device, wherein one of the fulcrums of the sheet feeding guide member having a positioning surface with respect to the body drum has an elongated hole.