JP2613236B2 - Paper feeder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder for an electrostatic copying machine.

2. Description of the Related Art In an electrostatic copying machine, two or more paper feed cassettes are often provided, but a paper feed path for feeding paper from a plurality of paper feed cassettes to a transfer portion of a single photosensitive drum is provided. The transport paths coming out of the respective paper feed cassettes join at the entrance of the nip portion of the pair of transport rollers common to the respective paper transport paths.

FIG. 1 is a diagram showing an example of a paper feeder of a wet copying machine having two paper feed cassettes.

At the front end of the upper surface of the sheet bundle placed on the bottom plate of the two sheet cassettes 18, two feed rollers 1 are sequentially provided, respectively.
When two or more sheets are sent out at the same time, the separation roller 2 for separating the double feed is provided in pressure contact with the second delivery roller, and only one sheet is sent out toward the common relay conveyance roller 8. Each transport path is constituted by guide plates 3, 4 and 6, 7, and the paper sent out from each sheet cassette 18 is guided by guide plates 3, 4.
4: Guided by 6 and 7, inserted into the nip of relay conveyance roller 8, skew correction is performed by relay conveyance roller 8 to register roller pair 11 via the conveyance path constituted by guide plates 9 and 10. The sheet is fed to the transfer section between the photosensitive drum 17 and the transfer charger 13 at a predetermined timing. Charger 14,
The toner image formed on the photosensitive drum 17 by the electrophotographic process means such as the wet developing unit 12 is transferred to the transfer paper fed from the paper feed cassette 18 by the action of the transfer charger 13, and the separation broad 15 ' Then, the toner is conveyed to a fixing unit (not shown) by the turn roller 15 and the turn belt 15 ″ to be fixed. The residual toner on the photosensitive drum 17 is cleaned by the cleaning unit 16.

Two guide plates of which the non-guide surfaces are opposed to each other among the guide plates 3, 4: 6, and 7 constituting the transport path from the two paper feed cassettes 18 described above.
Auxiliary guide plates 5, 5 'made of a thin elastic plate are attached to the front ends of the 4, 6 respectively.

However, in the paper feeder of this configuration, when one of the auxiliary guide plates of the adjacent transport path whose non-guide surfaces face each other is pushed and bent by the waist of the sheet, the leading end of the other auxiliary guide plate is moved toward the transport path. And may hinder the conveyance. Also,
In particular, when the auxiliary guide plate is pushed by the paper stiffness, the displacement amount of the auxiliary guide plate is large, the paper conveyance path becomes close to a straight line, and the leading end of the paper is connected to the relay conveyance roller pair 8. At a position distant from the contact portion of the relay conveyance roller 8, the smooth insertion into the relay conveyance roller pair 8 is hindered, and a conveyance failure is likely to occur.

By the way, as the auxiliary guide plates 5, 5 ', a polyester film or the like having a stable quality and versatility is used, but since the tip is conventionally used in a state where the tip is cut off, Paper dust is generated by the paper being squeezed at the leading edge, and is scattered or adheres to the paper surface, which adheres to the relay roller 8 or the registration roller 11, which reduces the coefficient of friction and reduces the conveying force. Let it cause a jam. This is a problem that occurs in both the wet copying machine and the dry copying machine. In particular, in the case of the wet electrostatic copying machine, there is a remarkable influence of paper dust which is not generated in the dry electrostatic copying machine.

The wet type copying machine employs a recycling system in which a liquid in a developing tank for storing a developing solution is supplied to and collected from both a developing unit and a cleaning unit. Therefore, when paper dust is generated due to squeezing, fraying, etc. in the transfer paper transfer process, the paper dust is transferred from the transfer paper which is in close contact with the photoreceptor to the surface of the photoreceptor at the time of transfer, and is cleaned together with the residual toner by the cleaning unit and is removed by the developer. Collected in the developing tank. The developing tank is provided with a toner concentration sensor for the developing solution. When the toner concentration detected by the developing tank falls below a predetermined value, the toner is replenished and the predetermined toner concentration is maintained. As a toner density sensor, a type in which a light emitting unit and a light receiving unit are opposed to each other with a gap of about 0.5 to 2.0 mm, and a toner density is detected by constantly flowing a developer between the light emitting unit and the light receiving unit is widely used. . In this method, since the gap between the light emitting section and the light receiving section is narrow, when the paper dust collected from the cleaning section is caught in the gap, toner adheres to the gap and gradually grows on the light emitting face and the light receiving face, and finally grows in the gap. Is filled, and the sensor performs erroneous detection.Even if the actual developer concentration is low, it is erroneously detected as if the toner concentration is high, and toner supply is not performed. , The density of the developed image decreases. Also, paper powder becomes sludge in the developer and accumulates in the developer circulation path, resulting in overflow of the developer from the circulation path.

Further, in a dry copying machine, when paper dust is clogged between the cleaning blade and the photosensitive drum, halftone black streaks appear on the copy, and the copy quality deteriorates.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described circumstances of a conventional paper feeding and conveying device of an electrostatic copying machine, and has a configuration in which one of the first opposing auxiliary guide plates is bent by being pushed by the waist of a sheet and the other auxiliary guide plate is bent. An object of the present invention is to provide a paper feeding and conveying device that does not cause the leading end of a guide plate to protrude into a conveying path and that can smoothly insert the leading end of a sheet into a pair of relay rollers even when a strong paper is fed. Secondly, it is an object of the present invention to provide a paper feeder that generates less paper dust.

Configuration In order to achieve the first object, the sheet feeding / conveying device of the present invention is configured such that, when one of a pair of auxiliary guide plates whose non-guide surfaces face each other exceeds a predetermined value, the other guide plate has a non-guide surface. A means for transmitting a deflection load is provided. Second
In order to achieve the above object, a curvature is provided at the leading end of the inner surface of the paper of the auxiliary guide plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing the details of the auxiliary guide plates 5, 5 'of the embodiment in which the present invention is applied to the paper feeding and conveying device described in FIG. Two auxiliary guide plates 5, 5 'with non-guide surfaces facing each other
In both cases, the front end is bent 180 ° on the opposite side of the guide surface by press working or the like, so that the bent front end has an appropriate curvature. Further, projections 21 and 21 'are respectively provided on the opposite surfaces of the sheet guide surface. Normally, the tip of this projection is slightly separated from the auxiliary guide plate of the other party.

Since this device is configured as described above, when paper is conveyed, even if it is rubbed at the leading ends of the auxiliary guide plates 5, 5 ', it has an appropriate curvature, so that almost no paper dust is generated. . As shown in FIG. 3, when ordinary paper is conveyed through the lower conveyance path and the auxiliary guide plate 5 'is pushed,
If there are no projections 21 and 21 'as in the prior art, the auxiliary guide plate 5' bends and the tip of the auxiliary guide plate 5 protrudes into the lower conveying path as shown by the broken line in the figure to convey the paper. May hinder. However, in this embodiment, the projections 21 and 21 '
Is provided, when the auxiliary guide plate 5 'is pressed and bent, when the amount of deflection exceeds a certain value, the bending load is transmitted to the other auxiliary guide plate 5 via the projections 21 and 21'. This prevents the tip of the auxiliary guide plate 5 from protruding into the lower transport path.

Further, when a sheet having strong stiffness is conveyed through the lower conveying path, the pressing force by the leading end of the sheet is provided by the bending stress of the two auxiliary guide plates 5, 5 'by providing the projections 21, 21'. Because of the support, the amount of displacement is reduced as compared with the case without the projections 21 and 21 ′, and even a stiff paper can be smoothly guided to the contact portion of the roller pair 8.

The means for transmitting the deflection load is not limited to the protrusion as shown in FIG. 2, but may be a block member 22, 22 'interposed between the two auxiliary guide plates as shown in FIG. Good.

Also, the means for imparting a curvature to the tip of the auxiliary guide plate can be formed by another known method.

Effects As described above, according to the present invention, even paper having strong stiffness can be smoothly inserted into the pair of transport rollers without being hindered by the auxiliary guide plate of the adjacent paper transport path. The generation of paper dust in the conveying section is prevented, and the occurrence of jams due to a decrease in the conveying force of the conveying rollers and the occurrence of a decrease in the developer concentration can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sheet feeding / conveying apparatus 1 of a copying machine to which the present invention is applied.
FIG. 2 is a sectional view showing the vicinity of an auxiliary guide plate according to an embodiment of the present invention, FIG. 3 is an explanatory view for explaining the operation thereof, and FIG. 4 is an auxiliary view of another embodiment of the present invention. It is sectional drawing which shows the front-end | tip part of a guide plate. 1 ... delivery roller, 3,4,6,7 ... guide plate, 5,5 '... auxiliary guide plate, 8 ... relay conveyance roller, 11 ... registration roller, 12 ... developing unit, 13 ... transfer Section, 16 Cleaning section, 17 Photoconductor drum, 21, 21 'Projection (flexure load transmission means), 22, 22' Block (flexure load transmission means)

Claims (4)

(57) [Claims] A plurality of feed rollers for feeding paper from each of a plurality of paper feed cassettes; and a plurality of pairs of guide plates for guiding the paper fed from each of the feed rollers to a common pair of transport rollers to form a transport path. And a non-guide surface of an adjacent conveyance path, and an auxiliary guide plate made of an elastic thin plate provided at the end of a guide plate opposed to each other. And a means for transmitting a deflection load to one of the auxiliary guide plates when the deflection of the auxiliary guide plate exceeds a predetermined value. 2. The method according to claim 1, wherein the deflection load transmitting means is a convex portion provided on the non-guide surface side of each of the opposing auxiliary guide plates and abutting against the non-guide surface of the other party when the deflection exceeds a predetermined value. The sheet feeding and conveying device according to claim 1, wherein the sheet feeding and conveying device is characterized in that: 3. The sheet feeding and conveying apparatus according to claim 1, wherein said flexible load transmitting means is a block member provided between the non-guide surfaces of the auxiliary guide plate facing each other. 4. A plurality of feed rollers for feeding paper from each of a plurality of paper feed cassettes, and a plurality of pairs of guide plates for guiding the paper fed from each feed roller to a common pair of transport rollers to form a transport path. And a non-guide surface of an adjacent conveyance path and an auxiliary guide plate made of an elastic thin plate provided at the end of a guide plate opposed to each other, in the sheet feeding device of an electrostatic copying machine, the non-guide surfaces face each other. Means for transmitting a deflection load to one of the auxiliary guide plates when a deflection exceeds a predetermined value, and a curvature provided at a leading edge of a paper guide surface of the auxiliary guide plate. Transport device.