JPH01117142A - Paper separator - Google Patents

Abstract

PURPOSE:To keep off any double feed of paper surely as checking an amount of paper powder to be produced to the smallest possible extent by installing an actuating means which varies an overlap according to temperature and humidity. CONSTITUTION:A friction pad 24 and a paper feed roller 23 are overlapped whereby paper is waved, and thereby paper separation takes place. At the time of high temperature when a paper electrostatic charge value is relatively small, the friction pad 24 is pulled down by contraction of a form memory alloy spring 30, whereby an overlap is relatively reduced. With this reduction, resistance between the friction pad 24 and the paper is made smaller, and an amount of paper powder to be produced is restrained. At the time of low temperature when the paper electrostatic charge value is relatively much, the friction pad 24 is pulled up by dint of tensile force of a tension spring 29 whereby the overlap is made larger, and thereby any double feed of the paper is yet surer prevented from occurring.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a paper feed section such as an intermediate tray of a copying machine, in which two
This is to prevent more than one sheet of paper from being fed at the same time.

(Prior art) Generally, when sheets used in copying machines and the like are stacked in an electrostatically charged state, two or more sheets are transported at the same time (multiple feeding) when the paper is fed, causing problems in subsequent paper transport. It is possible to give

In particular, in a copying machine capable of double-sided copying, the paper stocked in the intermediate tray has passed through the mechanical loading chamber and is highly charged, so the paper must not be fed from the intermediate tray. If this is done, a paper separation device is required to prevent φ feeding.

Conventionally, there is such a paper separation system as shown in FIG. 5. This device includes a separation roller 102 and a pad 103 for separating paper 101, and a recess 103a corresponding to the separation roller 102 on the surface of the pad 103 facing the separation roller 102.
is provided, and the recess 103a of this pad and the separation roller 10
2 and 2 are arranged so as to overlap with each other (see dimension a in FIG. 5). According to such a configuration, the paper 101 sandwiched between the separation roller 102 and the gate of the pad 103 is fed in an undulating state, which spreads the paper and prevents double feeding.

Incidentally, the band weight of such paper 101 is generally larger when the temperature is low and low humidity than when the temperature is high and humidity. (Dimension a in FIG. 5) needs to be set large.

However, when the overlap amount is set large like this, the resistance of the pad against the paper increases, so
When this paper is rubbed against the pad, the amount of paper dust generated increases, and especially when applied to an intermediate tray separation device, the paper dust may scatter near the photoreceptor drum and affect the image. There is sex.

(Objective of the Invention) In view of the above circumstances, an object of the present invention is to provide a paper-portion II device that can reliably prevent double feeding of paper while minimizing the output of paper dust. .

(Structure of the Invention) The present invention includes a separation roller that rotates in the paper conveyance direction, and a pad that is disposed opposite to the separation roller and has a recessed portion formed on the opposing surface corresponding to the separation roller. In a paper separation 5A system in which these pads and separation rollers are arranged so as to overlap each other and sheets are separated and conveyed by both, these pads and separation rollers are arranged so that the suspension of the overlap is variable. In addition, the device is provided with an actuation means for changing the overlap depending on temperature or humidity.

According to this configuration, when the paper band Im is relatively small, such as at high temperature or high humidity, the operating means reduces the amount of overlap between the separation roller and the pad, thereby minimizing the generation of paper dust, and In a state where the paper is charged relatively much, such as when the temperature is low or the humidity is low, double feeding of paper can be reliably prevented by increasing the "overlap".

(Example) Figure 2 shows a configuration that allows double-sided copying on paper. The internal structure of an IP photocopier is shown. A contact glass 1 is disposed on the top surface of this copying machine, and an automatic document feeder (ADF) 3 having a document tray 2 is disposed above it.

Inside the main body of the copying machine, a photoreceptor drum 4 is provided, and peripheral devices for the photoreceptor drum 4 include a main charging device I5, a developing device! ! 6, transfer device ff7, minute ill
Device i! 8. A cleaning device 9 etc. is installed,
An optical system 10 is provided above the photoreceptor drum 4 for irradiating an image of a document placed on the contact glass 1 onto a predetermined position on the photoreceptor drum 4 .

On the other hand, a paper feed cassette 11 is mounted on one side of the copying machine body in a plurality of stages and is removably installed, and the paper in the paper feed h set 11 is passed through a paper feed path 13 to the photoreceptor. The paper is supplied to the drum 4 and sequentially passes through a conveyor belt 14, a fixing device 15, and a pair of paper discharge rollers 16, and is discharged onto a paper discharge tray 17.

Further, in this copying machine, the pair of paper ejection rollers 16
A switching mechanism C for switching the paper path is provided immediately upstream of the paper feed path 13, and a return path 18 for reversely feeding the paper is provided between the switching mechanism C and the paper feed path 13.

The switching mechanism C includes a guide path for guiding the paper ejected from the fixing device 15 to the output tray 17 side, and a paper reverse feeding path 19 provided above the switching mechanism C.
It is configured to switch between a passage that guides the user and a passage that guides the user.

An intermediate tray 20 is provided in the middle of the return path 18 to temporarily suspend the paper, and a paper feed device is provided downstream of the intermediate tray 20 to refeed the suspended paper. 21 are provided.

The paper feeder N21 includes a paper feed roller 22 for refeeding paper;
It is composed of a paper separating device including a separating roller 23 and a friction pad 24, and a stopper 25, and the separating roller 23 and friction pad 24 are arranged facing each other on the downstream side of the paper feed roller 22. . Stopper 25
can be switched between a state of protruding from the upper surface of the intermediate tray 20 and a state of being retracted by a solenoid or the like, and in the protruding state, the leading edge of the paper fed backwards is aligned.

When the duplex copying mode is selected in such a copying machine, a series of copying operations are performed, and the standard 11i
1! After one side of the paper is fixed by step 1!15, the paper is once transported from the switching mechanism C to the reverse feed path 19, and is transported backward from this reverse path 19 to the intermediate tray 20.
When the paper is re-fed from the intermediate tray 20 face down to the photosensitive drum 4, the photosensitive drum 4 transfers the paper to the back side and discharges the paper.

Next, the above paper feed system! The detailed structures of the separation rollers 23 and friction pads 24 in 21 are shown in FIGS. 1 and 3 to 4.
This will be explained based on the diagram.

The separation roller 23 is connected to a shaft 26 extending in the front-rear direction of the copying machine main body.
The rollers are provided at two locations on the shaft 26, and are configured to be rotated together with the shaft 26 in the feeding direction.

The friction pad 24 is made of a material having a high coefficient of 1III with respect to paper, such as urethane rubber, and has a recess corresponding to the separation roller 23 on its upper surface 24a (the surface facing the separation roller 23). 24b is formed.

This friction pad 24 is fixed to the upper surface of the mounting bracket 27, and is provided between the downstream end of the intermediate tray 20 and the upstream end of the guide plate 28, as shown in No. 38. ing. Moreover, the *rubbing pad 24 is placed in such a position that the *m pad 24 and the paper feed roller 23 overlap, that is, the lower surface 23a of the separating roller 23 is located at the FJ.
It is arranged at a position lower than the upper surface 24a of the FIA pad 24.

A long hole 27a extending vertically is formed in the center of the mounting bracket 27, and a screw 31 fixed to the guide plate 28 side is fitted into this long hole 27a. Movement in the width direction is restricted. Mounting portions 27k) extending toward the intermediate tray 20 are provided on both sides of the mounting bracket 27, and the upper portion of the mounting portion 27b is attached to the intermediate tray via a tension spring 29 made of a normal metal material. A shape memory alloy spring (actuating means) 30 is interposed between the lower part of the attachment portion 27b and the intermediate tray 20. That is, the friction pad 24 and its mounting bracket 27 are suspended from above by the tension spring 29.

The shape memory alloy spring 30 is soft and easily deformed at a temperature below a predetermined temperature, but when the temperature exceeds a predetermined temperature, it contracts against the tensile force of the tension spring 29 in order to return to a pre-memorized shape. The mounting bracket 27 and the friction pad 24 are pulled downward by the forceps.

On the other hand, protrusions 27 are provided on both sides of the mounting bracket 27.
c protrudes, and on the guide plate 28 side, an 11υ1 portion 32 consisting of two protrusions 28a and 28b arranged above and below is provided, and the protrusion 27c is located on both protrusions 28a and 28bfl. The mounting bracket 27 is arranged as shown in FIG. Therefore, the mt* pad 24 and the mounting bracket 27 are movable between a position where the protrusion 27c abuts the upper protrusion 28a and a position where the protrusion 27C abuts the lower protrusion 28b.

In the paper separation device having such a structure, when the temperature is higher than a predetermined temperature, the shape memory alloy spring 30 is in a contracted state in order to return to the memorized shape, and therefore the friction pad 24 and the mounting bracket 27 are Against the tensile force, the protrusion 27c is pulled down to the position where it abuts the lower protrusion 28a (the state shown by the solid line in FIG. 1), and the separation roller 23 and friction pad 24 overlap by the dimension a shown in FIG. - rap. Therefore, when the separation roller 23 is rotationally driven and the paper passes between the separation roller 23 and the 11111112 pad 24, the paper is fed in a wavy state when viewed from the direction shown in FIG. Paper separation (preventing double feeding) is performed.

Note that the overlap ala at this time is set to the minimum value that can sufficiently prevent double feeding at high temperatures when double feeding is relatively unlikely to occur.

On the other hand, at low temperatures below a predetermined temperature, the shape memory alloy spring 30 is flexible and easily deformed, so the friction pad 24 and the mounting bracket 27
9, the protrusion 27c is pulled up to a position where it abuts the upper protrusion 28a (the state shown by the broken line in FIG. 1 and in FIG. 3). Therefore, the amount of overlap between the paper feed roller 23 and the rIllI pad 24 at this time is greater than that at the above-mentioned high temperature, and the paper is separated with even stronger action.

As described above, according to this paper separation device, the friction pad 2
4 and the paper feed roller 23 to cause the paper to wave, thereby separating the paper. At high temperatures when the amount of electrical charge on the paper is relatively small, the contraction of the shape memory alloy spring 30 causes the friction pad 24 to wave. By lowering , the amount of overlap is made relatively small, thereby reducing the resistance between the am pad 24 and the paper, and suppressing the amount of paper dust generated. By pulling up the friction pad 24 using the tensile force of the tension spring 29, the amount of overlap is increased, thereby making it possible to more reliably prevent double feeding of sheets.

Note that in this example, rsF! ! Although the amount of overlap is changed by moving the pad 24 up and down, the same effect can be obtained by moving the separation roller 23.

The shape memory alloy spring 30 is not limited to one that contracts when heated as described above, but may also be one that expands when heated. In this case, the friction pad 24 is suspended from above using a shape memory alloy spring,
If the structure is supported from below by a compression spring, the same effect as in the above embodiment can be obtained.

Further, in the same embodiment, the amount of overlap is changed according to the temperature by utilizing the deformation of the shape memory alloy spring 30 that follows the temperature change, but the present invention is not limited to this. It is equipped with a temperature sensor or a humidity sensor that detects temperature and humidity, and heats or cools the memory alloy spring according to the detected value.
*Rub pad 24 or separation roller 2 by solenoid etc.
3 may be moved. In the case where the amount of overlap is changed depending on the humidity, the amount of overlap may be increased when the humidity is low and the amount of charge on the paper is relatively large.

Furthermore, as a modification, the same effect can be obtained by changing the depth of the recess 24b in the paper feeding direction and moving the FJ rubbing pad 24 or separation roller 23 in the paper feeding direction.

Further, the paper separating device of the present invention is not limited to the paper feeding device 21 that feeds paper from an intermediate tray as in the above embodiment, but can also be applied to a paper feeding section of a normal copying machine.

(Effects of the Invention) As described above, in the present invention, the concave portion of the pad and the separation roller correspond to each other, and the pad and the separation roller are arranged in an overlapping state, and the amount of overlap is controlled by the temperature. Alternatively, since it is equipped with an actuation means that changes the charge according to the humidity trend, when the amount of charge on the paper is relatively small, such as at IX temperature or high humidity, the amount of overlap between the separation roller and the convex portion is reduced by the actuation means. While minimizing the generation of paper dust,
By increasing the amount of overlap when the four sheets are relatively large, double feeding of sheets can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a front view of a paper-portion IMS4 according to an embodiment of the present invention, FIG. 2 is an internal structure diagram of a copying machine in which the same device is installed in an intermediate tray, and FIG. 3 is a side view of the same device. FIG. 4 is a perspective view of the paper separation device, and FIG. 5 is a front view of the conventional paper separation device. 20... Intermediate tray (fixed side), 21... Paper feeder, 23... Separation port 0, 24...** Pad, 24a
...Top surface of friction pad (opposite to separation roller), 2
4b... recess, 30... shape memory alloy spring (actuation means). Patent applicant Sanda Kogyo Co., Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Chief 1) Masame Patent Attorney Yasuo Itaya 1st Figure 1 Figure 3

Claims (1)

[Scope of Claims] 1. A separating roller that rotates in the paper conveyance direction, and a pad that is disposed opposite to the separating roller and has a recessed portion corresponding to the separating roller on the opposing surface, and In a paper separation device in which these pads and separation rollers are arranged so as to overlap each other and the paper is separated and conveyed by both, the amount of overlap between these pads and separation rollers is variable. What is claimed is: 1. A paper separating device characterized in that the device is configured as shown in FIG. 2. The pad is configured to be movable relative to the fixed side, and a shape memory alloy spring that expands and contracts with temperature changes is interposed between the pad and the fixed side. Paper separation device as described in section.