JPH0648609A - Paper feeding device - Google Patents

Abstract

PURPOSE:To prevent a high speed copying machine from feeding extra paper sheets. CONSTITUTION:In a copying machine wherein copying will not start until the document fed from a document tray 21 is set on a document table 1, and the paper sheet supplied from a paper sheet tray 5, 6 or 7 is set at the position of a register roller 8, after the documents on the document tray 21 is fed, whether there are documents on the document tray 21 is detected, and only while there are documents on the document tray 21, a paper sheet on which the image of the next document is copied is fed.

Description

Detailed Description of the Invention

[0001]

This invention relates to a high speed copying machine,
The present invention relates to a paper feeding device that feeds originals and paper.

[0002]

2. Description of the Related Art A general copying machine is provided with a photosensitive member and a process device such as a charging device and a developing device at the center of the copying machine main body, and forms a toner image on the surface of the photosensitive member. A copy image is formed by transferring the toner image onto a sheet. A paper cassette is attached to the side or bottom of the main body of the copying machine to store paper. During the copying process, the toner image is transferred to the paper fed from the paper cassette. After being fed from the paper cassette, the paper in the paper cassette comes into contact with a registration roller arranged in front of the photosensitive member and temporarily stops (paper setting is completed). Then, the conveyance is started at the timing of being superimposed on the toner image.

A document feeder may be provided on the upper part of the main body of the copying machine. The document feeding device is a device that conveys a document placed on a document tray to the document table (sets a document) and returns the document on the document table to the document tray after scanning processing.

In the copying machine configured as described above, the document scanning (copying process) is started by the fact that the document is set on the document table and the paper is set at the registrar position. .

[0005]

When the document set and the paper set trigger the start of the document scanning as described above, the time until the document is set on the platen or the paper is set at the registration roller position. The time determines the copying speed. For this reason, high-speed copying becomes difficult with a copying machine in which it takes time to set an original or set paper. In many cases, the paper setting time is an obstacle to high-speed copying. If the paper cassette is installed at the bottom of the copier body,
This is because the distance from the paper cassette to the registration rollers becomes long and the time until the paper is conveyed to the registration rollers becomes long.

In order to realize high-speed copying in a copying machine in which the distance between the paper cassette and the registration rollers is long as described above, it is conceivable to start the paper feeding from the paper cassette early. That is, while the original is fed after the previous copying process is completed, the sheet is fed while the previous copying process is being performed. By feeding the next sheet during the previous copying process, the time from the completion of the previous copying process until the setting of the next sheet is completed is shortened, so that high-speed copying can be realized. Become.

However, if the paper feeding for the next copying processing is started before the previous copying processing is completed, the paper may be fed even though there is no original to be copied next. It was

An object of the present invention is to provide a sheet feeding device which prevents excessive sheets from being fed in a high speed copying machine.

[0009]

According to the present invention, there is provided a document setting means for feeding one document from a document bundle placed on a document tray and setting it on a document table, and a sheet bundle stored in a paper cassette. Sheet setting means for feeding one sheet of paper from the sheet and setting it at the registration roller position; and means for starting the copying process in a state where the original is set on the original table and the sheet is conveyed to the registration roller position. , After detecting the presence of the next original on the original tray after feeding the original on the original tray, when the presence of the next original is detected,
Before the feeding of the original document is started, a feeding control means for starting the feeding of the next original document from the paper cassette is provided.

[0010]

According to the present invention, after the document on the document tray is fed, it is detected whether or not there is the next document on the document tray. When there is the next document on the document tray,
The paper on which the image of the original is to be copied is fed from the paper cassette. In this way, the next paper is fed only when the next original is on the original tray, that is, the paper is fed only when the original corresponding to the fed paper is present. It will not be fed. Further, by starting the feeding of the paper before feeding the original, the timing of setting the paper is not significantly delayed from the timing of setting the original.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is a diagram showing a schematic construction of a copying machine.

A document table 1 is provided on the upper surface of the main body of the copying machine, and a circulating document feeder 2 is arranged above it. The circulation type document feeder 2 includes a document tray 21, a document feed belt 22, a document feed belt 23, and a document discharge roller 24.
And so on. A stack of documents is placed on the document tray 21. One document at the bottom of the document stack is fed by the document feeding belt 22 and set at a predetermined position A on the document table 21. The document feeding belt 23 is arranged on the document table 1, and the document is slid on the document table 1 to allow the document table 1 to slide.
The original is set at the predetermined position A of. By operating the document feed belt 23 and the document discharge roller 24, the document set on the document table 1 is discharged to the bottom of the document tray 21.

An optical system 3 is arranged below the document table. The optical system 3 includes a plurality of mirrors and copy lamps, scans a document set at a predetermined position A on the document table 1, and guides the reflected light to the photoconductor 4. A charging device, a developing device, and the like are arranged around the photoconductor 4 to form an image forming process section. An electrostatic latent image is formed on the surface of the photoconductor 4 by the reflected light of the document, and toner is attached to the latent image to form a toner image.

At the lower part of the copying machine main body, there are provided paper trays 5, 6 and 7 for accommodating paper for transferring a toner image. The paper trays 5, 6 and 7 are provided with paper feed belts 51, 61 and 71, respectively, and feed the paper in the corresponding paper cassette. Usually three paper trays 5,
Papers of different sizes are stored in 6 and 7,
At the time of copying processing, one sheet is fed from the bundle of sheets stored in the sheet tray 5 or 6 or 7 and conveyed to the photoconductor 4. The toner image on the photoconductor 4 is transferred to this sheet. The sheet fed from the sheet tray (any one of 5 to 7) hits the registration roller 8 arranged at a position before the photoconductor 4 and is temporarily stopped.

After that, the registration roller 8 starts to rotate and is fed to the photoconductor 4. A registration sensor S2 is provided in front of the registration roller 8. The registration sensor S2 detects the paper when the paper fed from one of the paper trays reaches the position of the registration roller 8, and is turned on. The paper-conveying rollers arranged in front of the registration rollers 8 (on the side of the paper tray) are configured such that the upper roller is lifted up when a certain force or more is applied. Therefore, when the sheet comes into contact with the registration roller 8 and stops, the upper roller floats up and the roller idles, so that the sheet cannot move any further.

The operation of the copying machine configured as above will be briefly described. The originals set on the original tray 21 are fed one by one to the predetermined position A, and a copy is made every time one original is set at the predetermined position A, and the originals are transferred to the original tray 21. Is discharged. When copying a plurality of originals from a plurality of originals, the entire originals are circulated to make one copy, and then the entire originals are circulated again to make a second copy. In this way, the desired number of copies is made. A round sensor S is placed on the document tray 21.
1 is arranged. The circulation sensor S1 is used for the document tray 2
When the originals are set to 1, the actuators are set so as to be placed on all the originals, and when the originals are circulated one by one, the returned originals are placed on the actuators. ing. When all the originals are circulated, the one-way sensor S1 is turned on, and at the same time, the actuator of the one-way sensor S1 is set on the originals on the original tray 21.

In such a copying machine, the copying process is started when the document is set at a predetermined position A on the document table 1 and the sheet reaches the registration rollers 8. FIG. 1 is a flow chart showing a processing procedure for feeding and scanning a document and a sheet, and FIG. 2 is a time chart for the same. Below, the procedure for feeding a document and a sheet and the procedure for scanning a document will be described. FIG. 2 is a time chart when the number of originals is three.

When the user operates the print switch, the process is started (n1). At the time of processing immediately after the operation of the print switch, that is, at the time of feeding the first original and the sheet, the feeding of the original and the sheet are started almost at the same time.
First, the document feeding belt 22 and the paper feeding belt (51
Alternatively, 61 or 71) operates (n2 → n3).
The document feeding belt 22 feeds the document on the document tray 21 to a predetermined position A, and the paper feeding belt (51, 61 or 71) feeds the paper of the paper tray (5, 6 or 7) to the registration roller 8. To send. After the document feeding belt 22 is turned on, the document is set at a predetermined position A on the document table after T _OSET . The setting state of the document on the predetermined position A is detected by the timer. That is, it is assumed that the document reaches the predetermined position A after T _{OS ET} after the document feeding belt 22 is turned on (n4). Further, after the paper feeding belt (51, 61 or 71) is turned on, the paper reaches the position of the registration roller 8 after T _PREG . The arrival of the sheet at the position of the registration roller 8 is detected by the registration sensor S2 (n5). Therefore, T _PREG is a measured value. The original is set at a predetermined position A on the original table 1, and the paper is set at the position of the registration roller 8 (registration sensor S2).
Is turned on) (at t1), the optical system 3 starts operating (n6). As a result, the document set on the document table 1 is scanned.

When the scanning of the original is completed, the original on the original table 1 is returned to the original tray 21 and the original on the original tray is fed to the original table 1 (n7 → n8). In this way, every time scanning of one document is completed, the document on the document tray is set at the predetermined position A on the document table 1.

On the other hand, the second and subsequent sheets are fed as follows. T _PCYC is determined by which paper cassette the paper is fed from. When the paper is fed from the paper cassette far from the registration roller 8, T _PCYC is set short, and when the paper cassette is close, the T _PCYC is set long (n11). T _PCYC is set upside down from the timing T _{2 when the} second document is set on the document table 1. That is, if the timing at which the second document is set on the document table 1 is T ₂ , then the second sheet is set to be fed before T _PREG . In addition,
The time T _SCAN required for exposing a document differs depending on the size of the document, and the timing T _{2 at} which the _second document is set on the document table also varies depending on the size of the document. Therefore, in this embodiment, the time for making the smallest copy (when the paper needs to be fed at the earliest) is set to T _PCYC.
Has been set as. However, T _PCYC may be set individually according to the size of the document.

When the feeding of the original is started at n3 or n8, the TS1 time is counted (n12). This TS
One hour later, the state of S1 is detected, and if S1 is on, sheet feeding is started after T _{PC YC} (n13 → n14 → n).
15). In S13, when S1 is off, that is, when there is no next original on the original tray, the paper is not fed. By controlling in this way, it is possible to prevent excess paper from being fed.

Although FIG. 2 shows an example in which three originals are copied, the copying cycle for the third part is repeated when a larger number of copies are to be made.

[0023]

According to the present invention, before the feeding of the sheet on which the copy image is formed next is started, it is judged whether or not the original of the image to be formed on the sheet exists, and the original exists. Only in this case, the feeding of the sheet is started, so that the wasteful sheet is not fed. Also, since the paper feed is started before the document feed is started,
The copying speed can be increased without significantly lengthening the time for setting the paper (setting to the registration roller position).

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure for setting a document and paper.

FIG. 2 is a time chart showing a procedure for setting a document and paper.

FIG. 3 is a diagram showing a schematic configuration of a copying machine.

[Explanation of symbols]

 1 Document Plate 2 Circulating Document Feeder 21 Document Tray 22 Document Feeding Belt 5, 6, 7 Paper Tray 51, 61, 71 Paper Feeding Belt A Predetermined Position S1 Loop Sensor S2 Registration Sensor

Claims (1)

[Claims] 1. An original setting means for feeding one original from a bundle of originals placed on an original tray and setting it on an original plate, and one sheet of paper from a bundle of papers stored in a paper cassette. To set the original to the registration roller position by means of a sheet, a means to start the copying process in a state where the original is set on the original table and the paper is conveyed to the registrar position, and the original on the original tray is fed. After the document is fed, the document detection unit that detects the presence or absence of the next document on the document tray, and when the presence of the next document is detected, the next document is fed from the paper cassette before the document feeding is started. A sheet feeding device comprising: a feeding control unit that starts feeding.