JPH05213474A - Paper sheet conveyor and image forming device using it - Google Patents

Abstract

PURPOSE:To enable registration surely even on small-size paper recording mediums. CONSTITUTION:Elasticity providing means 101 are provided at both end portions of a driven roller 12 and the driven roller 12 is kept being pressed into elasftic contact with a driving roller 11 and an elastically pressing means 101 for the driving roller 11 is provided on the middle axis portion 120A of the driven roller 12 other than both end portions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for improving the conveyance of a recording medium such as a sheet in an electronic copying machine or a laser printer, and an image forming apparatus using the apparatus. Is.

[0002]

2. Description of the Related Art In recent years, images such as names and addresses have been formed on a small-sized recording medium such as a business card using an electronic copying machine or the like.

Conventionally, in this kind of electronic copying machine,
A recording medium fed from the sheet feeding means into the apparatus main body is registered and guided to the image forming means built in the apparatus main body through a registration roller which is a recording medium conveying means, and is guided and conveyed. There is.

As shown in FIG. 5, such a registration roller is rotatably supported by a driving lower registration roller b, which is rotatably supported by a lower frame a of the apparatus body, and an upper frame c, which is vertically movable. And a driven upper registration roller d for
Elasticity imparting means composed of springs e, e are provided at both ends of the upper registration roller d to elastically maintain the upper registration roller d in pressure contact with the lower registration roller b.

[0005]

However, in the above-mentioned conventional structure, the elasticity imparting means composed of the springs e, e is provided only at both ends of the upper registration roller d, and therefore, FIG. As indicated by the two-dot broken line, the central portion of the upper registration roller d is warped up and floated above the lower registration roller b, and as shown by the dotted line in FIG. 5, for example, a small-sized recording medium P such as a business card.
Is conveyed to the central portion between the upper and lower registration rollers b and d,
Since the applied pressure is weak and the resist cannot be surely registered, the recording medium P is skewed and conveyed toward the image forming unit side, whereby the image cannot be formed on the recording medium P with high accuracy. There was a problem.

The present invention has been made under the above circumstances, and its purpose is to make it possible to reliably register even small-sized recording media such as paper sheets. An object of the present invention is to provide a conveying device and an image forming apparatus using the device.

[0007]

In order to solve the above problems, the present invention conveys paper sheets between a driving roller and a driven roller, and at the same time, elastic imparting means is provided at both ends of the driven roller. In a paper sheet conveying device provided with the driven roller elastically kept in pressure contact with the drive roller, the elastic force with respect to the drive roller is provided at least at one position of the intermediate shaft portion excluding both ends of the driven roller. The paper sheet conveying apparatus is characterized in that a pressing means is provided.

Further, according to the present invention, an image having recording medium conveying means for registering and guiding the recording medium fed from the sheet feeding means into the apparatus main body to the image forming means built in the apparatus main body is provided. In the forming apparatus, the recording medium conveying means is composed of a driving lower registration roller and a driven upper registration roller, conveys the recording medium between these rollers, and is elastic at both ends of the upper registration roller. The upper registration roller is elastically kept in pressure contact with the lower registration roller by providing means, and the lower registration roller is provided at at least one position of the intermediate shaft portion excluding both ends of the upper registration roller. In the image forming apparatus using the above-mentioned paper sheet transporting device, elastic pressing means is provided.

[0009]

That is, according to the present invention, by adopting the above configuration, the elastic imparting means is provided at both ends of the driven roller to elastically maintain the driven roller in pressure contact with the driving roller, and Since the elastic pressing means for the drive roller is provided at at least one position on the intermediate shaft portion excluding both end portions, the conventional lifting of the driven roller at the central portion is prevented.

Further, by adopting such a paper sheet conveying device as a registration roller which is a recording medium conveying means of an image forming apparatus, even a recording medium of a small size can be surely registered. It is possible to prevent skew of a recording medium having a small size.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 4. FIG. 2 is an electronic copying machine as an image forming apparatus using the paper sheet conveying apparatus according to the present invention. 1 schematically shows the entire internal configuration of the device, in which 1 is a device main body,
Reference numeral 2 is an image forming means 2 provided in the apparatus main body 1.

The image forming means 2 has a photosensitive drum 3 as an image bearing member which is rotatably and axially supported at a substantially central portion of the apparatus main body 1. Around the photosensitive drum 3, a developing unit is provided. The device 4, the transfer device 5, the peeling device 6, the cleaning device 7, the charge eliminating device 8 and the charging device 9 are arranged in this order.
The photoconductor drum 3 rotates clockwise and is uniformly charged by the charging device 9.

An original placing table 10 made of platen glass is provided on the upper surface of the apparatus main body 1, and an automatic original feeding device 20 for automatically feeding an original (not shown) is provided on the original placing table 10. It is provided. Furthermore, 3 in the figure
Reference numeral 0 denotes an exposure device as an exposure means arranged below the document table 10.

The exposure apparatus 30 includes an exposure lamp 32 whose back portion is bent by a reflector 31, a first, a second, and an exposure lamp 32.
Third reflecting mirrors 33, 34, 35, a lens 36,
The optical system includes fourth, fifth, and sixth reflection mirrors 37, 38, 39, and the like.

That is, an image of an original document (not shown) placed on the original document table 10 is scanned by the exposure device 30 and is exposed on the photosensitive drum 3 of the image forming means 2. The electrostatic latent image formed on the photosensitive drum 3 is developed by the developing device 4 to form a developed image.

On the other hand, on one side of the apparatus body 1,
First and second paper feed means 50 are provided, and the paper feed means 50 is composed of a paper loading section 51 that stores copy paper (not shown) as a recording medium, and is picked up from this paper loading section 51. The copy sheets are taken out one by one through the roller 52 and the sheet feeding roller 53, and the first sheet feeding means 50 can manually feed a small recording medium P such as a business card. ing.

The copy paper taken out is
A registration roller 11, which is a recording medium conveying unit described later,
The sheet is conveyed while being guided to a transfer device 5 disposed opposite to the photoconductor drum 3 via 12, and the developed image developed by the developing device 4 by the transfer device 5 is a copy sheet. It is designed to be transcribed on top.

The copy paper after the transfer by the transfer device 5 is peeled off by the peeling device 6 by AC corona discharge, and is fixed by the fixing belt 1 via the conveying belt 13 which is a conveying means.
4 is conveyed, and the fixing device 14 melts and fixes the developed image on the copy paper.

The copy sheet after the fixing is taken out by the take-out roller pair 15 provided at the downstream side of the fixing device 14, and the gate 16 provided at the downstream side of the take-out roller pair 15.
Is switched to a sheet discharge tray 17 provided outside the apparatus main body 1 via a sheet discharge roller 17, or
Alternatively, it is again conveyed to the reversing means 19 formed inside the apparatus main body 1.

The copy sheet conveyed to the reversing means 17 is switched back to the registration roller pair 1
It is guided and conveyed again through 1 and 12 to the transfer device 5 arranged to face the photoconductor drum 3 by this.
Both sides can be copied. Further, the residual toner remaining on the photosensitive drum 3 after the transfer and peeling of the developed image onto the copy paper is scraped off by the cleaning blade 71 of the cleaning device 7, and the scraped used toner and Waste toner containing foreign matter is conveyed to the transport roller 7.
2 is discharged to the outside of the cleaning device 7. The photoconductor drum 3 cleaned by the cleaning device 7 has its potential reduced to a certain level or lower by the neutralization device 8 to enable the next copying operation.

That is, the above-mentioned recording medium conveying means is
As shown in FIGS. 1, 3 and 4, the lower resist roller 11 for driving and the upper resist roller 12 for driving are formed, and both ends of the roller shaft 110 of the lower resist roller 11 are bearings. 111,1
11 through the lower frames 1A, 1 of the device body 1
It is axially supported between A.

On the other hand, the both ends of the roller shaft 120 of the upper registration roller 12 have bushes 121, 121.
Via the slot 1, is inserted between the elongated holes 100, 100 provided in the upper frames 1B, 1B of the apparatus main body 1, is axially supported so as to be vertically movable, and the elongated hole 1 of the upper frames 1B, 1B is
The bushes 121, 121 exposed to the outside from 00, 10 are provided with elasticity imparting means composed of springs 122, 122 so that the upper registration roller 12 is elastically maintained in pressure contact with the lower registration roller 11. ..

Then, the upper registration roller 12 is
For example, the shaft portion 120A of the roller shaft 120 is separated into left and right parts 12A and 12B so as to expose the shaft portion 120A of the roller shaft 120 with a gap width W narrower than the business card size in the center portion, and the shaft portion 120A of the roller shaft 120 is placed on the shaft portion 120A. Is provided with elastic pressing means 101 supported by the upper frame 1B of the apparatus body 1.

The elastic pressing means 101 is composed of a pressing body 102 which is supported by the upper frame 1B of the apparatus main body 1 so as to be vertically movable, and a spring 103 which biases the pressing body 102 downward. , The pressing body 102
Is brought into contact with the shaft portion 120A of the roller shaft 120 to apply a load to the central portion of the upper registration roller 12 and prevent the intermediate portion of the roller shaft 120 other than both ends from being warped. ..

Further, reference numerals 112 and 113 in the figure denote first rollers provided on the roller shaft 110 of the lower registration roller 11.
And a second drive gear, 123 is a driven gear provided on the roller shaft 120 of the upper registration roller 12, and the first drive gear 112 is transmitted from a drive system of the apparatus main body 1 not shown. The lower registration roller 11 is rotated by being driven by a driving force to rotate the lower registration roller 11, while the driven gear 123 meshes with the second driving gear 113 to rotate the upper registration roller 12. ..

In the above-described embodiment, the elastic pressing means 101 is provided at one central portion of the upper registration roller 12.
The roller shaft 120 is configured to be elastically pressed by, for example, the left and right side portions of the intermediate portion of the roller shaft 120 excluding both end portions.
Elastic pressing means 101 may be provided at a position.

[0027]

As is apparent from the above description, according to the present invention, elasticity imparting means is provided at both ends of the driven roller so that the driven roller is elastically maintained in pressure contact with the driving roller and the driven roller is driven. Since the elastic pressing means for the drive roller is provided at at least one position of the intermediate shaft portion excluding both end portions of the roller, it is possible to prevent the floating of the driven roller in the central portion as in the past.

Further, by adopting such a sheet conveying device as a registration roller which is a recording medium conveying means of the image forming apparatus, it is possible to surely register a recording medium of a small size. It is possible to prevent the skew of the recording medium having such a small size, and thus it is possible to accurately form an image on the recording medium.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an essential part showing an embodiment of an image forming apparatus using a paper sheet conveying apparatus according to the present invention as a recording medium conveying unit.

FIG. 2 is an explanatory view schematically showing the overall internal configuration of the image forming apparatus.

FIG. 3 is a sectional view taken along line AA of FIG.

FIG. 4 is an explanatory view showing a separated state of upper and lower registration rollers which also constitute a recording medium conveying unit.

FIG. 5 is a schematic cross-sectional view of a registration roller that constitutes a recording medium conveying unit in a conventional image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Device main body, 1A ... Lower frame, 1B ... Upper frame, 2 ... Image forming means, 11 ... Driving roller (lower registration roller), 12 ... Followed roller (upper registration roller), 100 ... Long hole, 101 ... Elastic pressing Means, 102 ...
Pressing body, 103 ... Spring, 110 ... Roller shaft of driving roller, 120 ... Roller shaft of driven roller,
120A ... Shaft, 122 ... Elasticity imparting means (spring), P ... Recording medium.

Claims (2)

[Claims] 1. A paper sheet is conveyed between a driving roller and a driven roller, and elastic imparting means is provided at both ends of the driven roller to elastically maintain the driven roller in pressure contact with the driving roller. In the paper sheet transporting device configured as described above, an elastic pressing means for the drive roller is provided in at least one position of the intermediate shaft portion excluding both ends of the driven roller. 2. An image forming apparatus comprising recording medium conveying means for registering and guiding a recording medium fed from a paper feeding means into the apparatus main body to an image forming means built in said apparatus main body. The recording medium conveying means is composed of a driving lower registration roller and a driven upper registration roller, conveys the recording medium between these rollers, and provides elastic imparting means at both ends of the upper registration roller. While the upper registration roller is elastically kept in pressure contact with the lower registration roller, elastic pressing means for the lower registration roller is provided at at least one position of the intermediate shaft portion excluding both ends of the upper registration roller. An image forming apparatus comprising: