JPH0372378A - Paper refeeding device for composite image forming device - Google Patents

Abstract

PURPOSE:To improve the paper refeeding performance and to preclude jam occurrence by switching a conveying means to a conveyance release state after a form which is refed from an intermediate tray overpasses a multiple feed preventive paper feeding means. CONSTITUTION:In a process wherein the form (a) which is stocked in the intermediate tray 23 is refed, a solenoid 37 is excited every time a paper refeed signal is inputted to position a conveyor roller 34 on the uppermost paper surface in the intermediate tray 23, and then the upper most form (a) is refed to a multiple feed rod paper feeding means 28; when a paper detection sensor S detects the front end of the form (a) passes the multiple feed preventive paper feeding means 28, the solenoid 37 is turned off, the conveyor roller 34 is moved up separately, and the conveying means 25 is switched to the conveyance release state. Consequently, the paper refeeding performance is improved and the jam occurrence is precluded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper refeeding device installed in a composite image forming apparatus such as an electrostatographic copying machine capable of composite copying such as superimposed copying and double-sided copying. It is something.

[Conventional technology]

As the above paper refeeding device, for example, as shown in FIG.
The conveying means 53 for refeeding the paper a stocked in the intermediate tray 51 to the double-feed prevention sheet feeding means 52 is set to the conveying operation state X.
and conveyance release state By, and each time a paper refeeding signal is input, the conveyance means 53 is switched to the conveyance operation state X.
In addition, when the leading edge of the sheet reaches the double-feed prevention paper feeding means 52, there is a system in which the conveyance means 53 is switched to the conveyance release state MY.

Then, in consideration of the slippage of the conveyance means 53, the amount of conveyance of the paper a by the conveyance means 53 is adjusted so that the leading edge of the sheet can be reliably conveyed to the double-feed prevention sheet feeding means 52. In order to prevent the conveyance of the second sheet a stocked in the intermediate tray 51, the above paper conveyance amount is set to be large. is set to be a dimension from the trailing edge of the smallest size paper a to be fed to the conveyance action point Q.

[Problem that the invention seeks to solve]

However, if the paper to be conveyed a is slippery or has paper dust attached to it, or if the conveyance means 5
3 itself, the amount of slip of the conveying means 53 changes, so the leading edge of the paper may not reach the double-feed prevention paper feeding means 52. In particular, the leading edge of the paper stocked in the intermediate tray may not be aligned. When the above-mentioned conveying means 53 is used as the means for forwarding to the stopper,
From the point of view of edge alignment, it is better to reduce the frictional resistance of the conveyance means 53 somewhat, but this would make the paper conveyance amount even more unstable when refeeding the paper, and if the paper to be fed is long. In the case of the shaku size, since the conveyance resistance between the contact surfaces of the paper a is large, the leading edge of the paper is also
There were cases where the paper could not reach the number 2, resulting in the inability to refeed the paper and the occurrence of paper jams.

The present invention was developed in view of the above-mentioned circumstances, and includes:
The purpose of this invention is to make it possible to refeed paper in a predetermined manner through extremely simple improvements, thereby improving paper refeeding performance and preventing paper jams.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a conveying means for refeeding sheets stocked in an intermediate tray to a double-feed prevention sheet feeding means, which can be freely switched between a conveying operating state and a conveying release state. The present invention is characterized in that a paper detection sensor is disposed near the downstream side of the double-feed prevention paper feeding means, and the conveyance means is switched to a conveyance release state based on paper detection information from the paper detection sensor. be.

[Effect]

According to the above characteristic structure, regardless of changes in the slip amount of the conveyance means or differences in conveyance resistance between contact surfaces of the paper, if the leading edge of the paper is conveyed a certain distance beyond the double-feed prevention paper feed means, , the conveyance means is switched to a conveyance release state.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a composite copying type electrophotographic copying machine as an example of a composite image forming apparatus. A charging device 5, two developing devices 6 containing different color developers, a transfer device 7, a paper separating device 8, and a cleaning device 9 are arranged around the device case 3, and an optical system is installed in the upper space of the device case 3. A paper feed conveyance device 12 is provided with a movable exposure device W10, and conveys the paper a stored in the upper and lower cassette paper feed sections 11 to the transfer device 7, and a paper feed and conveyance device 12 that transports the paper a after the transfer and minutes M. a discharge conveyance device 14 that conveys the sheet to the fixing device 13;
A pair of paper ejecting rollers 16 are also provided to eject the fixed paper a to a paper ejecting tray 15.

A refeeding device 17 having an electric transmission prevention function is provided in the lower space of the device case 3, and a switchback conveying means 18 switches the sheet a after single-sided copying to feed it to the refeeding device 217. A reversing sheet feeding means 19 is disposed for reversing the sheet a after one-sided copying and feeding it to the sheet re-feeding device 217, and Conveying l! which merges and feeds the paper to the paper feed conveyance device 13! 20 is provided.

By changing the conveyance path by the first path switching mechanism 21, the sheet a after one-sided copying is taken out to the tray 15, and the sheet a after one-sided copying is transferred to the paper refeeding device 17.
The second path switching mechanism 2
By changing the conveyance path in step 2, paper a after single-sided copying is
It is possible to select a paper take-out mode for double-sided copying in which the sheet a is fed to the switchback conveyance means 18, and a paper take-out mode for composite copying in which the sheet a after single-sided copying is fed to the reversal conveyance means 19. It is composed of

As shown in FIGS. 2 and 3, the paper refeeding device 17 includes an intermediate tray 23 that accommodates the paper a after single-sided copying;
It is located on the downstream side of the intermediate tray 23 in the paper refeeding direction and serves as a leading edge alignment stopper 24 for aligning the leading edges of the paper a stored on the intermediate tray 23, and also serves to advance the paper a to this stopper 24. and a conveyance means 25 that sequentially refeeds the uppermost sheet a on the intermediate tray 23 each time a refeeding signal is input, and a drive means 26 that switches the stopper 24 to a non-operating state at the time of refeeding. The register 112 of the paper feeding and conveying device 12 prevents paper a from being fed twice when refeeding the paper.
- a double-feed prevention sheet feeding means 28 that feeds sheets to the roller 27; and detecting that the leading edge of the paper has passed through the double-feed prevention sheet feeding means 28, the conveying means 25 is changed from a conveying operation state X to a conveyance release state Y;
A paper detection sensor S is provided to switch the paper.

The double-feed prevention paper feeding means 28 has a paper feeding roller 30 fixed to the longitudinal center of the rotary shaft 29, and a clutch 31 that is switched to a paper feeding transmission state for a predetermined period of time each time a paper refeeding signal is input manually. is provided on one end side of the rotating shaft 29, while a double feeding prevention roller 32, which is rotatable by a predetermined angle in the opposite paper feeding direction, is provided in contact with the paper feeding roller 30. When two sheets of paper a are fed between the paper feed roller 30 and the double-feed prevention roller 32, only the paper a on the paper feed roller 30 side is fed. .

The conveyance means 25, which also serves to forward the paper a to the stopper 24, is constructed as follows.

That is, the 17-shaped arm 33 is loosely fitted onto the rotary shaft 29 provided with the paper feed roller 30 of the double-feed prevention paper feeding means 28, and the transport roller 34 is loosely fitted on the loose #A side of the L-shaped arm 33.
An endless belt 36 is wound around the transport roller 34 and a rotating body 35 connected to the rotating shaft 29, and a solenoid 37 for swinging the 15-shaped arm 33 is provided. It is linked to the letter-shaped arm 33.

In the step of stocking the intermediate tray 23 with the paper a after single-sided copying, the solenoid 37 is energized every time the paper is fed onto the intermediate tray 23, and this causes the transport roller 34 to move toward the intermediate tray 23. By being positioned above the paper fed above, the paper a is placed on the stopper 2.
At the same time, the solenoid 37 is demagnetized and the paper is conveyed toward the conveyance roller 34 side.
The conveyance means 25 is configured to be switched to the conveyance release state Y by being separated above the plane of the paper.

Alternatively, the paper a stocked in the intermediate tray 23
In the step of refeeding the paper, the solenoid 37 is energized every time a paper refeed signal is input, and as a result, the conveyance roller 34 is positioned on the uppermost paper surface on the intermediate tray 23. The paper a is fed by the double feed prevention paper feeding means 28
When the paper detection sensor S detects that the leading edge of the paper a has passed through the double-feed prevention paper feeding means 28, the solenoid 37 is demagnetized and the transport roller 34 is moved upward. The conveyance means 25 is configured to be switched to the conveyance release state MY by being moved away from the conveyance means 25.

The conveyance amount of paper a by this conveyance means 25 is the point Pl
The dimension from to the paper detection point Pl of the paper detection sensor S is
The dimension from the trailing edge Pl of the paper of the minimum size to be fed to the conveyance action point Pl is set to be small, thereby preventing the conveyance of double sheets a, and the conveyance Regardless of changes in the slip amount of the means 25, differences in conveyance resistance between the contact surfaces of the sheet a, etc., the sheet a is configured to be conveyed a certain distance until the leading edge of the sheet is detected by the paper detection sensor S. There is.

In the embodiment, the conveyance means 25 also serves as means for conveying the paper a to the leading edge alignment stopper 24, but each means may be provided separately.

〔Effect of the invention〕

As explained above, the present invention waits for the paper re-fed from the intermediate tray to pass the double-feed prevention paper feeding means, and then switches the transporting means to the transport release state, and the slipping of the transporting means Paper can be reliably transported to the specified position regardless of differences in transport resistance between paper contact surfaces, etc.
This makes it possible to reliably prevent the occurrence of paper jams and the inability to refeed the paper due to the leading edge of the paper not reaching the double-feed prevention paper feeding means.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional side view of an electrophotographic copying machine as an example of a composite image forming apparatus, FIG. 2 is a perspective view of a paper refeeding device, FIG. 3 is a side view of the paper refeeding device, and FIG. FIG. 5 is a block diagram of a conventional paper refeeding device. 23... Intermediate tray, 25... Conveying means, 28...
・Double feed prevention paper feeding means, a... Paper, S... Paper detection sensor, X... Conveyance operating state, Y... Conveyance release state. Applicant: Mita Kogyo Co., Ltd. Agent: Hideo Fujimoto, patent attorney

Claims (1)

[Claims] A conveyance means for refeeding the paper stocked in the intermediate tray to the double-feed prevention sheet feeding means is provided so as to be freely switchable between a conveying action state and a conveyance release state, and is provided near the downstream side of the double-feed prevention sheet feeding means. A paper refeeding device for a composite image forming apparatus, characterized in that a paper detection sensor is disposed, and the transport means is switched to a transport release state based on paper detection information from the paper detection sensor.