JPH0639307B2 - Intermediate paper feeder for copiers - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an intermediate sheet feeding device of a copying machine that stacks copy sheets that have passed through an image forming section and then re-feeds them to the image forming section.

2. Description of the Related Art Conventionally, it is more conventional to provide an intermediate paper feeding device of the above type in a copying machine capable of screen copying in which copy images are formed on both sides of copy paper or composite copying in which copy images are formed on the same side of copy paper. It is well known. This type of conventional intermediate paper feeding device has one intermediate tray for stacking copy papers, and the papers on this tray are successively re-fed by the feeding means. There are cases where copy sheets are stacked on the intermediate tray with the copy image side facing up, and there are cases where copy sheets are stacked with the copy image side facing down.Usually, the copy images face up in the double-sided copy mode. In the composite combined mode, the copied images are usually stacked with the images facing downward. The copy sheets stacked in this manner are sequentially re-fed by the feeding means, but when the conventional feeding means is configured to feed the copy sheets on the intermediate tray from the topmost paper, it is always the highest. If it is configured to feed paper from the uppermost paper and from the lowermost paper, the copy paper is always sent out from the lowest paper. However, it has become clear as a result of recent studies that this configuration causes the following drawbacks.

The intermediate sheet feeding device illustrated in FIG. 4 has a sheet feeding roller 50 that comes into pressure contact with the uppermost sheet C1 of the copy sheets C stacked on the intermediate tray 23, and a sheet feeding unit including a friction pad 51. By rotating the paper feed roller 50 in the clockwise direction, the copy paper C is re-fed one by one from the uppermost paper C1. At this time, if the copy paper C is stacked on the intermediate tray 23 with the surface on which the copy image T is formed facing downward, this will be the next copy paper when the top paper C1 is re-fed. When sliding on C2, the paper feed roller 50
Presses the uppermost paper C1 downward, the image surface of the uppermost paper C1 is strongly rubbed against the paper feed roller corresponding portion 52 of the second copy paper C2. Therefore, as shown in FIG. 5, the roller corresponding portion 52 of the second copy paper C2 is rubbed in a state where the toner slightly separated from the image of the first copy paper C1 is accumulated, and the toner is rubbed there. Contamination occurs.

On the contrary, as shown in FIG. 6, the copy paper C is stacked on the intermediate tray 23 with the surface on which the copy image T is formed facing upward, and is fed from the uppermost paper C1 by the rotation of the paper feed roller 50. If so, the image formed on the roller corresponding portion 52 of the second copy paper C2 comes into sliding contact with the first copy paper C1.
The image of the roller corresponding portion 52 of the first copy paper C2 does not rub against the same place on the top paper C1, but rather the top paper C1.
From the front end to the rear end, it rubs over its entire length, so
The toner on the second copy paper is a little peeled off, and this is the top paper C.
Even if it adheres to No. 1, it is dispersed on the surface of the copy paper C1, and the stain is not noticeable and does not become recognizable stain.

For the same reason as described above, when the copy sheets are stacked on the intermediate tray with the image side facing up and the sheets are fed again from the bottom sheet, the copy sheets are placed on the copy sheet surface as in FIGS. 4 and 5. Contamination of the toner occurs, and when the copy sheets stacked with the copied images facing downward are re-fed from the lowest paper, the substantial contamination of the toner does not occur as in FIG.

As described above, depending on the orientation of the image surface of the copy sheet and which of the upper and lower copy sheets is to be fed, the copy sheet may or may not be soiled, and therefore the toner may not be soiled. In addition, if the copy paper is always re-fed by the method shown in FIG. 6, for example, toner contamination can be prevented. However, as described above, since the orientation of the image forming surface of the copy sheets stacked on the intermediate tray changes depending on the copy mode (duplex copy, composite copy), it is always necessary to re-feed the copy sheets as shown in FIG. It was not possible to carry out this process, and it was often the case that copy paper had to be re-fed in the manner shown in FIG.

The purpose of the present invention is based on the above-mentioned novel recognition. The purpose of the present invention is to re-feed the copy paper from the top paper and the bottom paper. An object of the present invention is to provide an intermediate paper feeding device capable of preventing the generation of recognizable toner stains on the copy paper surface.

Structure The present invention includes first and second intermediate trays for stacking copy sheets, first-class feeding means for feeding the copy sheets stacked on the first intermediate tray from the topmost sheet, and stacking on the second intermediate tray. A configuration including a second feeding unit that feeds the copied copy paper from the lowest paper is proposed.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a copying machine having an intermediate paper feeding device according to the present invention. In this copying machine, a copying paper final processing device 4 and an automatic document feeder 2 which are connected to a copying machine main body 1 are used as required. It is attached.

The automatic document feeder 2 is arranged on the upper part of the copying machine body 1, and the document D is set on the paper feed tray 5 and the paper feed belt 6 on the right side thereof. The lowermost original is fed rightward in the drawing by the operation of the belt 6, and is conveyed around the clockwise rotating roller 7 as indicated by an arrow A, and is fixed to the copying machine main body 1. It is fed onto the contact glass 8 by a conveyor belt 9 placed opposite thereto, and is left stationary at a predetermined position. At this time, the original has its image surface facing the contact glass 8.

On the other hand, the copying machine main body 1 supports a photosensitive drum 10 which is driven to rotate in a counterclockwise direction, and an image forming means including a charging charger 11, a developing device 12 and the like is arranged around the photosensitive drum 10, and above the drum 10. An imaging optical system 14 including a light source 13 is arranged. The original document stopped on the contact glass 8 is illuminated by a light source 13 which scans and moves in the direction of the arrow, and the reflected light passes through an optical system to a charging charger.
The surface of the photoconductor drum 10 charged by 11 reaches the surface, and a latent image corresponding to the original image is formed on the drum 10. This latent image is visualized by toner as it passes through the developing device 12, and this visible image is selectively transferred from the first or second paper feeding device 15 or 16 to the transfer portion of the photosensitive drum 10, that is, the image. The copy image transferred to one surface (first surface) of the copy paper C fed to the forming unit is fixed by the fixing device 17. The residual toner on the drum 10 is cleaned by the cleaning device 18.

After the illumination processing by the light source 13 is completed, the document is conveyed by the conveyor belt 9
Is re-actuated to the left, conveyed around the turn roller 19 and returned to the paper feed tray 5 (arrow B),
The originals are stacked with the image surface facing upward from the other originals stacked here.

The other side of the copy paper on which the copy image is formed on the first side (second side)
In the double-sided copy mode in which a copy image is also formed on the front side), the copy paper is sent to the reverse guide 21 of the reverse device 20,
The traveling direction is switched from the direction of arrow E to the direction of arrow F, and this is fed to the intermediate sheet feeding device 22 according to the present invention.
The intermediate paper feeding device 22 includes two first and second intermediate trays 23a and 23b, a switching means including a switching guide member 42 that selectively guides the copy paper to the intermediate trays, and the intermediate trays 23a and 23b. Of the first side and the second feeding means 37a and 37b for feeding the copy paper, and in the double-sided copy mode, the copy paper having the first surface copied is fed to the first intermediate tray 23a. In this case, the switching guide member 42 is the first
2 and FIG. 2, the copy paper is guided by the guide member 42 and the fixed guide plate below the copy paper toward the first intermediate tray 23a, and by the discharge roller 29a. It is reliably fed to the first intermediate tray 23a. At this time, the copy paper is already in the reversing device 2.
Since it is subjected to the reversing action (switching of the traveling direction) by 0, it is stacked on the first intermediate tray 23a with the first surface on which the copied image is formed facing upward. The ejected copy paper is stopped at a predetermined position where the leading end region reaches the leading end region of the first intermediate tray 23a.

The above operation is sequentially performed a predetermined number of times,
As shown in FIG. 2, a plurality of copy papers C are stacked on the first intermediate tray 23a with the copy images T facing upward, and after the number of copies reaches a predetermined number, the first feeding means 37a. Paper is re-fed.

The illustrated first feeding means 37a includes a first intermediate tray 23a.
It has a paper feed roller 24 and a separation roller pair 25 for re-feeding the upper copy paper C from the uppermost paper C1.

At the time of re-feeding the copy paper on the first intermediate tray 23a, the paper feed roller 24 is lowered or the intermediate tray 23a is moved up so that the uppermost paper C1 and the paper feed roller 24 are fed to the second paper sheet, as is known per se. As shown by the chain line in the figure, the sheets are pressed against each other and the sheet feeding roller 24 starts rotating in the clockwise direction. As a result, the uppermost sheet C1 is sent to the left in FIG. 2, and the double feed is prevented by the pair of separating rollers 25, and it is sent to the image forming section as indicated by arrows Ga and G, and to the transfer section of the photosensitive drum 10 in this example. Is sent. As a result, a copy image can be formed on the second surface of the transfer paper C1, and the copy paper C1 passes through the fixing device 17 again, and after the image on the second surface is fixed, the reversing device 20 normally reverses the copy paper C1. It is ejected from the copying machine main body 1 as it is, as indicated by an arrow H, without receiving it.

As described above, the copy paper C on the first intermediate tray 23a is 1
The sheets are re-fed one by one, and at that time, each copy sheet faces the image side upward and is fed by the sheet feeding roller 24 from the topmost sheet, so that the description will be given with reference to FIG. For the reason described above, the noticeable toner stain does not occur on the copy paper surface.

The copy sheet discharged from the copying machine main body 1 is carried into the copy sheet final processing device 4, and when the switching guide plate 40 occupies the position of the chain line at that time, the copy sheet is discharged as it is to the sheet discharge tray 41, and the final sheet. It is considered as copy paper. Further, when the guide plate 40 is switched to the position indicated by the solid line, the copy sheets are placed on the stapler tray 26, and when the number of the copy sheets reaches a predetermined number, the stapler 3 automatically binds the copy sheets to the sheet surface of FIG. On the other hand, the doggy tail 27 that can swing back and front
The bundle of copy papers that are discharged to and are bound to each other are sorted one by one.

In the composite copy mode in which the copy image is formed on the first surface of the copy paper fed from the first or second paper feeding device 15 or 16 as described above, and then the superimposed copy image is formed on the same surface. The copy paper on which the image on the first side is fixed by the fixing device 17 after leaving the photoconductor drum 10 is conveyed in the direction of arrow F without being fed to the reversing guide 21 of the reversing device 20, and the intermediate paper feeding device 22. Sent to. Therefore, the copy sheet sent to the intermediate sheet feeding device 22 has the image forming surface facing downward, and by re-feeding the copy sheet to the image forming portion of the photoconductor drum 10, the copy sheet surface on which the image is already formed is formed. A duplicate image can be formed by overlapping.
This is the reason why the copy sheets are stacked on the intermediate sheet feeding device 22 with the image forming surface facing downward. If the copy sheets are sent to the above-described first intermediate tray 23a, the copy sheets are fed to the first intermediate tray 23a.
If the paper is re-fed from above by the feeding means 37a,
Due to the reason shown in FIG. 4, the copy paper surface is contaminated with toner as shown in FIG.

Therefore, in the composite copy mode, the switching guide member 42 is switched to the position shown by the chain line in FIG.
It is discharged to the second intermediate tray 23b by 9b, and a predetermined number of copy sheets C are stacked on the tray 23b. The copy paper C is fed by the second feeding means 37b when the paper is re-fed, and the feeding means 37b is provided with the two rollers 2.
It has a feeding belt 30 wound around 8 and 29, and a feeding roller pair 31, and the belt 30 is located in a notch formed in the second intermediate tray 23b, and the lowermost copy paper C3 is located on the upper surface thereof.
Is in contact with.

At the time of re-feeding, the upper surface of the belt 30 operates in the arrow direction, and an intake device (not shown) sucks the lowest paper C3 in the arrow K direction. At this time, as shown by the arrow L, it is advantageous to blow air on the leading edge of the copy paper so as to provide a separating action, so that double feeding can be prevented. In this way, only the lowermost paper C3 is sent out to the left in FIG. 3, and is conveyed in the directions of the arrows Gb and G through the feed roller pair 31, and the image is transferred from the photoconductor drum 10 to the same surface of this copy paper. Is transcribed. Next, this copy paper is subjected to an image fixing action by the fixing device 17, and then discharged as shown by an arrow H to the outside of the main body of the copying machine. Of course, this copy paper can be turned upside down or
Send to the intermediate tray 23a or the second intermediate tray 23b,
Double-sided copying or subsequent composite copying processing may be performed.

When the copying machine shown in FIG. 1 discharges the copy sheet only by copying it on the first side, the copied sheet on the first side is reversed by the reversing device 20 or without being reversed. Of course, the sheet is discharged as it is, that is, without being fed to the intermediate sheet feeding device 22.

As described above, the copy sheets on the second intermediate tray 23b are stacked with the image T facing downward, but when the sheets are re-fed, they are fed from the lowest order sheet C3. For the same reason as 6), no noticeable toner stain is given to the copy paper C4 on the lowest paper. In this way, copy sheets are stacked on the first or second intermediate tray according to the double-sided copy mode and the composite copy mode, and the copy sheets are placed on the upper side or the lower side depending on the direction of the copy sheets stacked on the tray. Since the toner is fed from above, the toner can be prevented from being soiled in any case.

In the case of the copying machine shown in FIG. 1, the copy sheets stacked in the intermediate paper feeding device faced the image side upward in the double-sided copy mode, and conversely faced the lower side in the composite copy mode. , Its orientation depends on the configuration of the copying machine, and accordingly, it is necessary to feed the copying paper to each intermediate tray accordingly. For example, in the embodiment shown in FIG. 3, the direction of the copy sheets stacked in the intermediate sheet feeding device is opposite to that in the case of FIG.

The overall structure of the copying machine shown in FIG. 3 will be briefly described. An image of the document D on the contact glass 8 is imaged by the optical system 14 including the light source 13 on the photoconductor drum 10 charged by the charging charger 11. , This allows the drum 10
A latent image is formed on the latent image, which is visualized by the developing device 12. This image is transferred from the paper feeding device 15 to the copy paper fed as shown by arrows I and G, and is fixed by the fixing device 17. In the double-sided copying mode, this copy paper is subjected to the reversing action by the reversing device 20. Instead, it proceeds in the direction of arrow F as it is, and is sent to the second intermediate tray 23b by the switching guide member 35b and the discharge roller 29b which occupy the position of the solid line (arrow Mb). In this way, a predetermined number of copy sheets are stacked on the second intermediate tray 23b, and the copy sheets stacked at this time face the image side downward. The re-feeding of the copy paper is performed by the operation of the feeding belt 30 of the second feeding means 37b as in the case of FIG. 2, and the photoconductor drum 1 from the lowest copy paper is shown by arrows Gb and G.
It is fed toward 0. As a result, an image is formed on the surface of the copy paper on which an image has not been formed.

On the other hand, in the composite copy mode, the copy paper on which the image is formed on the photoconductor drum 10 passes through the fixing device 17 and is then sent to the reversing guide 21 of the reversing device 20 to undergo the reversing action (arrows E → F). The first intermediate tray 2 is rotated by the switching guide member 35a and the discharge roller 29a which are rotated to the position of the chain line.
3a (arrow Ma), and a predetermined number of copy sheets are stacked here. At this time, the copy paper faces the image forming surface upward.

At the time of re-feeding, also in this case, the paper feeding roller 24 of the first feeding means 37a descends, and the rotation of the uppermost copy paper causes the arrow to move in the same manner as the paper feeding from the first intermediate tray in FIG. As indicated by Ga and G, the image is sent to the photoconductor drum 10 and an image is formed by superimposing it on the surface on which the image is already formed. At this time, the switching guide member 35b is naturally rotated to the position indicated by the chain line.

In FIG. 3, reference numeral 36 is a switching guide member for switching the discharge of the copy paper to the paper discharge unit 38, and 39 is a control for switching the transfer of the copy paper to the copy paper final processing device (see FIG. 1). It is a switching guide member.

As described above, in the copying machine shown in FIG. 3, the copy paper is sent to the second intermediate tray 23b with the image side facing down in the double-sided copy mode, but when it is re-fed, it is sent from the lower copy paper. Further, in the composite copy mode, the copy paper is sent to the first intermediate tray 23a with the image side facing upward, and is re-fed from the copy paper on the upper side of the first intermediate tray 23a. Therefore, in any case, it is possible to prevent the copy paper from being contaminated with toner. .

As means for feeding the copy paper on the intermediate tray, it is obvious that various types of means other than those shown can be adopted. For example, as a feeding means for the first intermediate tray,
The configuration shown in the figure can also be adopted. The same applies to the reversing device. Further, the illustrated reversing device uses three rollers, and since the structure itself is already known, the description of its specific structure and operation is omitted.
Regarding this, for example, Japanese Utility Model Publication Sho-58-92
No. 246 and the like.

Advantageous Effects According to the present invention, it is possible to prevent the defect that the recognizable toner stain is formed on the copy paper surface regardless of the orientation of the copy paper stacked in the intermediate paper feeding device.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a copying machine equipped with an intermediate sheet feeding device according to the present invention, FIG. 2 is an enlarged sectional view of the intermediate sheet feeding device shown in FIG. 1, and FIG. FIG. 4 is a cross-sectional view of a copying machine in the example, FIG. 4 is a side view showing an example of a conventional intermediate paper feeding device, FIG. 5 is a plan view showing a state in which toner stains adhere to copy paper, and FIG. It is a side view which shows the same intermediate | middle paper feed device as the figure, and shows the state where the direction of copy paper is reverse. C, C1, C2, C3, C4 ... Copy paper 22 ... Intermediate paper feeding device, 23a ... First intermediate tray 23b ... Second intermediate tray 37a ... First feeding means, 37b ... Second feeding Sending means

Claims (1)

[Claims] 1. An intermediate sheet feeding device of a copying machine, which stacks copy sheets after passing through the image forming section and then re-feeds them to the image forming section, including first and second intermediate trays for stacking the copy sheets. First feeding means for feeding the copy sheets stacked on the first intermediate tray from the uppermost sheet, and second feeding means for feeding the copy sheets stacked on the second intermediate tray from the lowermost sheet. The above-mentioned intermediate sheet feeding device.