JPH0238505B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feeding device for accommodating paper that has been copied on one side and feeding it out again in a double-sided copying machine.

2. Description of the Related Art It has been well known to obtain copies by copying methods such as electrophotography. In this method, an electrostatic latent image is formed on a photoreceptor, then the toner image is transferred to a transfer sheet, fixed, and discharged from the copying machine to obtain a copy.

In recent years, in order to save paper or simplify the storage of copies, so-called automatic duplex copying, in which copies are automatically made on both sides of a sheet of paper, has come into use. This automatic two-sided copying can be roughly divided into one-sided copying of the desired number of copies using the first original, the sheets on which one-sided copying has been completed, and the paper that has been copied on both sides are temporarily stacked and stored in the paper feeder for double-sided copying, and then In order to copy on the back side of the paper using the second original, the single-sided copied paper is fed one by one from a paper feeder for double-sided copying to complete the double-sided copying, or the first
Complete single-sided copying for one sheet using the second original and place it in the duplex copying paper feeder, then copy on the back side of this sheet using the second original to make double-sided copying for each sheet of paper. A method is known in which the process is repeated for a desired number of copies.

In an automatic double-sided copying machine using the former method, for example, as shown in FIG. Form. This electrostatic latent image is developed by a developing device 3 to form a toner image. On the other hand, the transfer paper 4 is transported from the paper tray 5 or 6 by a paper transport device 7, and its position is corrected by a registration roller 8, so that it comes into contact with the toner image in synchronization with the rotation of the photosensitive drum 2. Next, the toner image is transferred to the transfer paper by the transfer corotron 9 and conveyed by the conveyor belt 10.
Then, the toner image is sent to the fixing device 11 and the toner image is fixed. After single-sided copying has been completed in this manner, the transfer paper is reversed by the paper reversing device 12, and then a desired number of sheets are stacked and stored in the double-sided copying paper feed device 13. Next, in order to perform backside copying, a second original is placed on the platen 1 and a toner image is formed on the photosensitive drum in the same manner as described above.

The transfer paper for back-side copying is fed from a paper feeding device 13 for double-sided copying, conveyed by a feed roller 14 for double-sided copying and a paper conveyance device 7, and is positioned by a registration roller 8, and then comes into contact with the toner image. After transfer and fixing are performed in the same manner as described above, the transfer paper on which double-sided copying has been completed is discharged from the copying machine by the paper discharging device 15 to obtain a double-sided copy.

The latter method differs from the former method in that it stores only one sheet of paper that has been copied on one side, then copies the back side, and then makes double-sided copies for each sheet of paper. In order to make it possible to copy the back side of a sheet that has been copied on one side, it is necessary to first store the sheet that has been copied on one side in a paper feeding device for duplex copying provided in the copying machine, and then feed the sheet again when copying on the back side. However, single-sided copied paper has a tendency to curl due to the heating or pressure action of the fixing device during single-sided copying, and since the front and back sides of the single-sided copied paper are reversed by the paper reversing device, especially When storing the first sheet of paper, the slippage between the paper feeder for double-sided copying and the paper becomes poor, and the first sheet of paper gets stuck in the middle of the paper feeder, causing a storage failure and the paper being fed for back-side copying. This results in the paper not being accurate.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a paper feeding device for a double-sided copying machine for accommodating single-sided copied paper and feeding it again, which eliminates the above-mentioned drawbacks.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper tray for accommodating single-sided copied paper, which is provided with a through hole approximately in the center, and a paper tray that rotates when storing and feeding the first sheet of single-sided copied paper. An auxiliary feed roller provided through the through hole of the receiver, and a paper that presses the paper against the auxiliary feed roller 20 and applies a conveying force to the auxiliary feed roller 20 when storing the first sheet of the single-sided copied paper. This can be achieved by a paper feeding device of a double-sided copying machine that includes a presser member 26 and a paper feeding means for feeding out the stored single-sided copied paper.

Next, the configuration of the present invention will be explained with reference to FIG.

16 is a conveying roller consisting of a pair of rollers that feeds the single-sided copied paper to the paper feeding device of the double-sided copying machine;
Reference numeral 17 denotes a detector that detects the entry of the paper fed by the conveyance roller 16. Reference numeral 18 denotes a paper receiver for storing paper, and a through hole 19 is bored approximately in the center of the paper receiver 18. 20 is paper tray 1
A rotatable auxiliary feed roller provided through the through hole 19 of 8 accumulates and accommodates the single-sided copied paper 21 on the upper surface of the paper receiver 18 and the upper surface of the auxiliary feed roller 20. Reference numeral 22 denotes a paper feeding unit provided at the rear end of the paper feeding device for feeding out the stored single-sided copied paper, and this paper feeding unit 22 consists of a feeding roller 23 and a separating roller 24, both of which move in the same direction It rotates counterclockwise (in the figure).

A paper leading edge detector 25 is provided near the paper feeding means 22 on the paper receiver 18 side (on the right side in the figure) to detect when the leading edge of the paper 21 that has moved on the paper receiver 18 has arrived. Note that 26 is a paper pressing member that presses the paper 21 for each sheet of paper that enters, and the pressing surface of this paper pressing member 26 is provided at a position that substantially faces the auxiliary feed roller 20 when pressing.
In addition, the paper pressing member 26 is provided so as to be movable up and down. This paper pressing member 20 is used to hold one side of a single-sided copy sheet.
When storing the first sheet on the top surface of the paper tray 18,
It presses the paper against the auxiliary feed roller 20 and applies a conveying force to the auxiliary feed roller.

In the paper feeding device of the present invention configured as described above, the single-sided copied paper is fed by the conveyance roller 16 and whose entrance is detected by the detector 17 is stored along the inclination of the paper receiver 18. When the first sheet of single-sided copied paper enters, the auxiliary feed roller 20 begins to rotate (counterclockwise in the figure) to move the paper toward the paper feeding section based on the entry detection signal from the detector 17. At this time, the paper pressing member 26 presses the paper against the auxiliary feed roller 20 and applies a conveyance force to the auxiliary feed roller 20. The paper 21 moved by the conveyance roller 16 and the auxiliary feed roller 20 is then detected by the paper leading edge detector 25 as the leading edge of the paper arrives, and based on this detection signal, the rotation of the auxiliary feed roller 20 is stopped to stop the movement of the paper. deposited and contained.

Such auxiliary feed roller 20 and paper pressing member 2
6, the leading edge of the first sheet of paper reaches the feed roller 23 and separation roller 24, which is the key to preventing misfeeds and double feeds when refeeding. Paper tray 1
8, and refeeding can be performed extremely smoothly.

When the second sheet of single-sided copied paper enters, it is moved over the first sheet by the action of the conveyance roller 16 without rotating the auxiliary feed roller 20, and is deposited and stored. The third and subsequent sheets are stacked and stored without rotating the auxiliary feed roller 20 in the same manner as the second sheet, and the process is repeated until the desired number of copies are stacked and stored. During stacking and storage, the paper pressing member 26 is actuated to press the paper for each sheet of paper stacked and stored, to correct curls of the paper, and to bring the paper into close contact with the paper receiver or auxiliary feed roller and the paper and each other. You may try to make it more sensitive.

The single-sided copied sheets stacked and housed in this manner are then sent out from the paper feeding device by the paper feeding means 22 in conjunction with the back side copying operation. This feeding is performed by operating the auxiliary feed roller 20, the feed roller 23, and the separating roller 24. Auxiliary feed roller 20, feed roller 23 and sorting roller 2
4 rotate in the same direction (counterclockwise in the figure) so that the stacked and housed single-sided copied sheets can be fed from the bottom side. The bottom sheet of paper is sent out by the rotational force of the auxiliary feed roller 20 and the feed roller 23, and even if two or more sheets of paper are sent out, the second and subsequent sheets are sent out by the rotational force of the sorting roller 24. Since the paper acts to be pulled back into the paper feeding device, it is possible to feed the paper one sheet at a time starting from the bottom side. At this time, in order to prevent stacking and lifting of the stored paper, or to ensure smooth feeding with the auxiliary roller 20,
The pressing surface of the paper pressing member 26 may be made to lightly contact the upper surface of the stacked paper.

As described above, the paper feeding device of the present invention rotates the auxiliary feed roller when storing the first sheet of single-sided copied paper, so that the paper can move smoothly on the paper tray, and the paper can move smoothly on the paper tray. Even if the paper is curled or the contact resistance between the paper and the paper holder is high, it can be moved smoothly.

In the above-described embodiment, the rotation and stop of the auxiliary feed roller was performed based on the detection signals of the detectors provided at the entrance and rear end of the paper feeder, but this is not necessarily limited to this. The time it takes the paper to reach the paper feeder and the time it takes the paper to move within the paper feeder may be measured in advance, and the auxiliary feed roller may be rotated or stopped based on this. The auxiliary feed roller may be rotated or stopped using the various paper conveyance detectors provided.

[Brief explanation of drawings]

Figure 1 shows an outline of an example of an automatic double-sided copying machine.
FIG. 2 is a sectional view of a paper feeding device showing an embodiment of the present invention. Codes in the figure: 1...platen; 2...photosensitive drum;
3... Developing device; 4... Transfer paper; 5, 6... Paper tray; 7... Paper transport device; 8... Registration roller; 9... Transfer corotron; 10... Transport belt; 11... Fixing device; 12... Paper reversing device ;13
... Paper feeding device for double-sided copying; 14... Feed roller for double-sided copying; 15... Paper ejection device; 16... Conveyance roller;
17, 25...Detector; 18...Paper receiver; 19...Through hole; 20...Auxiliary feed roller; 21...Single-sided copied paper; 22...Paper feeding means;23...Feed roller;24...
Handling roller.

Claims (1)

[Claims] 1. A paper tray 18 with a through hole 19 provided approximately in the center for storing single-sided copied paper, and a former paper tray 18 that rotates when storing and feeding the first sheet of single-sided copied paper. An auxiliary feed roller 20 provided through the through hole 19, and a paper that presses the paper against the auxiliary feed roller 20 and applies a conveying force to the auxiliary feed roller 20 when storing the first sheet of the single-sided copied paper. A paper feeding device for a double-sided copying machine, comprising a presser member 26 and a paper feeding means 22 for feeding out the stored single-sided copied paper.