JPH01247333A - Paper feeder - Google Patents

Abstract

PURPOSE:To enable a picture quality to be prevented from deteriorating of paper eliminated in its double feed by lowering a mounting plate in every end of feeding one sheet of paper so as to release the paper from its forced contact with a paper feed roll and paired paper feed rollers. CONSTITUTION:When a bypass paper feed is selected, paper 3 is detected for whether or not it is loaded on a tray 31, and the paper 3, when it is not loaded, is displayed on a control panel or the like. While the paper 3 is confirmed to exist, when a print key is operated by an operator, a solenoid 61 operates actuating an operating member 61a to a broken line position. In this way, the operating member 61a is released from its stopping to a pawl 62a of a clutch assembly unit 62. Thereafter when a mounting plate 5 lifts its front end part, the paper 3 on the plate 5 is forced to come into press contact with a paper feed roll 4, while paired paper feed rollers are forced to come into press contact by controlling the print key. Thus conveying the paper 3 to a side of the paired paper feed rollers, the paper is conveyed to a side of paired resist rollers 9 by rotating a paper feed roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device for feeding paper to a copying machine or the like, and particularly to a device used in a bypass paper feeding mechanism of a copying machine or the like.

[Background Art] In an image forming apparatus such as a copying machine, a paper feeding device for feeding recording paper is provided in the main body of the apparatus. There are various paper feeding methods, such as manual paper feeding, cassette paper feeding, and stack paper feeding for bypass (bypass paper feeding). Here, a paper feeding device used for bypass paper feeding of an image forming apparatus such as a copying machine will be particularly described.

In the bypass paper feed mechanism, a paper feed tray on which paper is stacked is provided outside the main body of a copying machine, etc., and a paper feed roller is provided above the leading edge of the paper. This paper feed roller is pressed against the paper and rotates to pull out the paper sheets one by one from the paper feed tray.On the downstream side of this paper feed roller, there is a roller for feeding the paper into the inside of the main body of the apparatus. A pair of paper feed rollers is provided. The paper feed roller pair includes a paper feed roller that is rotationally driven in a direction in which the paper is fed, and a reversing roller that is pressed against the paper feed roller via the paper. The reversing roller is driven to rotate in the opposite direction to the paper feeding roller, and when only one sheet of paper is conveyed between the paper feeding roller and the reversing roller, the paper is fed by the action of a torque limiter. Rotate in the direction you want. on the other hand,
If two sheets of paper overlap due to double feeding,
The paper in contact with the reversing roller is rotated so as to be returned to the tray side, thereby preventing double feeding.

[Problem to be solved by the invention]

As described above, double feeding is prevented by the action of the paper feed roller and the reversing roller, and the paper is fed one by one to the next pair of registration rollers. However, if the reversing roller is constantly in pressure contact with the paper feed roller, a situation may occur in which the leading edge of the paper is pinched by the pair of registration rollers and at the same time the rear end of the paper is pinched by the pair of paper feed rollers. In this case, it is necessary to pull the paper strongly on the registration roller side.
The load on the registration roller pair becomes large.

The drive of the pair of registration rollers is synchronized with the rotation of the photoconductor drum, so if the load on the pair of registration rollers increases as described above and paper slippage occurs,
Image shrinkage and character misalignment occur due to timing discrepancies.

Therefore, as shown in Japanese Unexamined Patent Publication No. 59-108631, a system has been proposed in which the paper is detected to have been conveyed to a predetermined position and the pressure contact between the pair of paper feed rollers is released based on the detection signal. has been done.

However, the conventional technique disclosed in this publication requires a large number of drive sources and members for releasing the pressure contact between the two rollers, and thus has a problem in that the structure becomes complicated.

Furthermore, in the device disclosed in the above publication, the forward feeding of the paper is stopped by releasing the pressure contact between the paper feed roller and the paper at the same time as releasing the pressure contact between the paper feed roller pair (reversing roller). At this time, the paper feed roller is raised. In such a system, if the pressure contact of the reversing roller is released and the electric feeding prevention mechanism is no longer activated as described above, double feeding may occur when feeding long sheets of paper. In other words, if the paper is long, the trailing edge may come into contact with the paper in the tray while the leading edge is sandwiched between the pair of registration rollers. In this case, the friction between the paper and the paper causes the next paper to be transported. are transported together. That is, as in the prior art described above, while releasing the pressure contact of the reversing roller,
In a system in which paper feeding is stopped by raising the paper feed roller, double feeding may occur after the pressure of the reversing roller is released.

The present invention has been made in view of the above points, and uses a simple mechanism to release the pressure contact between the pair of paper feed rollers each time the feeding operation of one sheet of paper is completed. It is an object of the present invention to provide a paper feeding device that can prevent double feeding after release and that can improve image quality especially when used in an image forming apparatus.

[Means to solve the problem]

As described above, in the paper feeding device, when the feeding operation for one sheet of paper ends, the pressure contact between the paper feeding roller and the paper is released, and the forward feeding of the paper is stopped. The pressure between the paper feed roller and the paper can be released by raising the paper feed roller as in the prior art, but it can also be done by lowering the paper, that is, the mounting plate on which the paper is placed. It is possible. For those that lower the board, a lowering mechanism is provided for this purpose.
The operating timing of this lowering mechanism coincides with the timing of releasing the pressure contact between the pair of paper feed rollers.

Therefore, the paper feeding device according to the present invention lowers the mounting plate on which the paper is placed every time the feeding of one sheet of paper is completed to release the pressure contact between the paper and the paper feeding roller, and The pressure contact between the pair of paper feed rollers is released each time the feeding operation of one sheet of paper is completed by using a lowering mechanism of the plate.

(Function) In the present invention, for example, the pressure release member connected to the reversing roller is lowered using the lowering mechanism of the mounting plate.

Therefore, by simply adding a simple connecting member, it is possible to realize a mechanism for releasing the pressure contact between the paper feed roller pair and release the pressure contact between the paper feed roller and the reversing roller each time the feeding operation for one sheet of paper is completed. It is possible to avoid problems such as the paper being pulled between the pair of paper feed rollers and the pair of paper feed rollers, and to eliminate causes of text blurring and the like. Moreover, since the pressure contact between the paper and the paper feeding roller is released by lowering the mounting plate, the paper will not be fed in duplicate even after the pressure contact between the reversing roller is released.

〔Example〕

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

FIG. 1 is a block diagram of a paper feeder according to an embodiment of the present invention, and this paper feeder feeds sheets 3 stacked on a tray 31 into an apparatus such as a copying machine. here,
A case will be described in which the paper feeding device according to the present invention is used as a bypass paper feeding device of a copying machine. A pair of registration rollers 9 are provided inside the copying machine main body, and a guide 11
The paper guided by the register rollers 9 and 12 is conveyed to an image forming section (not shown) by the pair of registration rollers 9. A pair of paper feed rollers for conveying paper is provided upstream of the pair of registration rollers 9, that is, on the right side in the figure. This paper feed roller pair is composed of a paper feed roller l for conveying the paper to the registration roller pair 9, and a reversal roller 2 that is pressed against the paper feed roller l via the paper. 2 is always urged toward the paper feed roller l by a biasing member (not shown).

Further, this reversing roller 2 is applied with a driving force in the direction of returning the paper to the tray side to prevent double feeding, but during normal conveyance, the torque limiter acts on the paper feed roller 2.
The paper feeding roller 1 rotates in the paper feeding direction together with the paper feeding roller 1 by the driving force of the paper feeding roller 1 .

A mounting plate 5 is provided between the pair of paper feeding rollers and the tray 31 on which the leading edge of the paper is placed, and above this mounting plate 5, the paper 3 on the mounting plate 5 is fed. A paper feed roller 4 is provided to move the paper to the opposite side of the paper roller. As is clear from FIG. 3, the mounting plate 5 includes a portion 53 on which the paper is placed, hinge portions 51 formed at both widthwise ends of the paper 1iII placement portion 53, and left and right hinge portions. 5
A locking part 5 formed to protrude laterally from one of the parts 1 to 1.
2. The rear end of the hinge portion 51 is
It is rotatably attached to the body frame of the copying machine, and can be rotated about the rear end of the hinge portion 51 by a mounting plate lowering mechanism 6, etc., which will be described later. Further, a spring 7 is provided below the front of the board 5 as shown in FIG.
The front part of 5 is urged upward by this spring 7.

Next, details of the board lowering mechanism 6 will be explained with reference to FIG. 3.The board lowering mechanism 6 has a clutch assembly 62. This clutch assembly 62 has a gear portion 62c driven by a gear train from a drive system, and has a spring clutch inside. Two pawls 62a and 62b are provided on the outer periphery of the cylindrical body δ2d in which the spring clutch is built.
0＠Arranged at opposite positions and offset in the axial direction. Further, a solenoid 61 is disposed close to this clutch assembly 62, and the tip of an actuating member 61a operated by this solenoid 61 is latched to either pawl 62a or 62b of the clutch assembly 62. It has become. A shaft 63 provided parallel to the drive shaft 41 of the paper feed roller 4 is fixed to the clutch assembly 62, and an oval lift cam is attached to the end of the shaft 63 on the opposite side of the clutch assembly 62. 64 is fixed (see Figure 1).

A pin 64b is attached to the eccentric position of the lift cam 64.
An arm 65 is rotatably connected via the arm 65. The arm 65 has an oval outer circumference, and an oval hole 65a having substantially the same shape as the outer circumference is formed from the center to the upper part. The locking portion 52 of the mounting plate 5 can be locked in this hole 65a.

Next, a mechanism for releasing the pressure contact between the pair of paper feed rollers using the loading plate lowering mechanism 6 will be described.

In FIG. 1, a pressure release member 8 is attached to the shaft 21 of the reversing roller 2 to release the reversing roller 2 from being pressed against the paper feed roller 1. As shown in FIG. This pressure release member 8 includes a shaft mounting portion 82 mounted on the shaft 21 of the reversing roller 2;
A connecting portion 84 extends downward from the shaft mounting portion 82 in parallel with the axis connecting the paper feed roller 1 and the reversing roller 2, and a cam that protrudes downstream from the connecting portion 84 and comes into contact with the cam surface 64a of the lift cam 64. It consists of a contact part 81. A guide groove 83 is formed at the lower end of the pressure release member 8, and a pin 85 is inserted into the guide groove 83. In FIG. 1, reference numerals 13 and 14 are guides for conveying the paper.

Next, the operation will be explained.

Bypass paper feeding in this embodiment is performed by vertical movement of the mounting plate 5, rotation of the paper feed roller 4, and paper feed conveyance by a pair of paper feed rollers. When bypass paper feeding is selected, it is detected whether paper 3 is placed on tray 31 or not. If the paper 3 is not placed, a message to that effect is displayed on the operation panel or the like. When the presence of paper 3 is confirmed and the print key is operated by the operator, the solenoid 61 shown in FIG. 3 is activated, and the actuating member 61a is activated to the position shown by the broken line in the figure. As a result, the actuating member 61a and the clutch assembly 62
The locking with the claw 62a is released.

The clutch assembly 62 always receives driving force from the drive system in the direction of the arrow in FIG.
2 is rotated by the wind 62a and the release of the engagement of the operating member 61a. After rotating 180 degrees, the wind 62a
The claw 62b located on the opposite side engages with the tip of the actuating member 61a located at the position indicated by the broken line, and rotation is stopped.

The rotation of the clutch rotor 62 causes the lift cam 64 to rotate 180'' via the shaft 63, and as a result, the arm 65 eccentrically attached to the lift cam 64 rises to the position indicated by the broken line in the figure. The locking portion 52 of the board 5, which has been pulled downward by the hole 65a of 65, is released.At this point, the board 5 is always urged upward by the spring 7, so it has not been pulled downward until then. The mounted board 5 rotates clockwise around the hinge portion 51, and its front end rises.As the front end of the mounted Fi5 rises, the board Fi5 is placed on the board 5. The placed paper 3 comes into pressure contact with the paper feed roller 4.

On the other hand, by operating the print key, the pair of paper feed rollers are brought into pressure contact. That is, before the print key is operated, the cam contact portion 81 of the pressure release member 8 is pressed by the cam surface 64a of the lift cam 64, and the reversing roller 2 is moved downward by the pressure release member 8 (the second (see figure). Therefore, the pressure contact between the paper feed roller pair is released. In this state,
When the print key is operated and the lift cam 64 rotates 180″' due to the above-mentioned operation, since the lift cam 64 is provided eccentrically, the position of its cam surface 64a rises, which causes the reversing roller 2 to move upward. A member (not shown) urging upward allows the reversing roller 2 to move upward and is brought into pressure contact with the paper feed roller 1 (the state shown in FIG. 1).

In this way, the paper feed roller 4 and the paper 3 are brought into pressure contact, and the paper feed roller pair is also brought into pressure contact. The paper feed roller 4 rotates clockwise, so that the paper 3 is conveyed to the opposite side of the paper feed roller. Since the paper feed roller 1 and the reversing roller 2 are brought into pressure contact with each other by the above-described operation, the paper dipped between the two rollers is conveyed to the registration roller pair 9 side by the rotation of the paper feed roller 1. At this time, for example, if two sheets of paper are fed double, the reversing roller 2 rotates in the opposite direction due to the difference in the friction coefficient between the sheets and the friction coefficient between the reversing roller 2 and the paper.
The paper on the reversing roller 2 side is sent back to the tray 31 side.

After a predetermined time has elapsed since the print key was operated, that is, after the feeding operation of one sheet of paper has ended, the solenoid 61 is turned off, and the actuating member 61a returns to the state shown in the solid line in FIG. 3. The lock with the claw 62b is released. Therefore, the clutch assembly 62 rotates 180'' in the same manner as described above, and then stops due to engagement with the pawl 62a. This rotation of the clutch assembly 62 causes the cam 64 to rotate 180@. The state shown in the figure is reached, and the arm 65 moves downward.This arm 65
The locking portion 52 of the mounting plate 5 is locked in the hole 65a, so that as the arm 65 moves downward,
The mounting plate 5 rotates counterclockwise around its hinge portion 51. As a result, the front end of the paper 3 separates from the paper feed roller 4, and the paper feed and conveyance operation stops.

On the other hand, due to the rotation of the cam 64, the position of the cam surface 64a moves downward, contrary to the paper feeding operation described above.
The cam contact portion 81 of the pressure release member 8 that contacts this cam surface 64a is pressed, and therefore the reversing roller 2 also moves downward via this pressure release member 8, and the pressure contact with the paper feed roller 1 is released. .

The pressure release member 8 is guided by its guide groove 83 and pin 85 to ascend and descend.

In this embodiment, the pressure contact between the paper feed roller l and the reversing roller 2 is released every time the paper feeding operation for one sheet of paper is completed, so that the leading edge of the paper is nipped by the pair of registration rollers 9. In this state, the trailing edge is released from the nip between the pair of rollers, and therefore the paper is smoothly conveyed to the image forming section, etc., which eliminates the cause of character blur caused by pressure contact between the pair of paper feed rollers. be able to. Furthermore, since the load on the pair of registration rollers 9 is small, torque fluctuations are reduced and image quality can be improved.

Furthermore, since the pressure contact between the pair of paper feed rollers is released during jam handling, the jammed paper can be easily removed.

Since the pressure contact between the pair of paper feed rollers is released using a mechanism for lowering the mounting plate 5, the pressure contact can be released by simply adding a simple member such as the pressure release member 8 to the conventional device. The mechanism can be realized and the device can be constructed at low cost. Furthermore, since the pressure contact between the paper feeding roller 4 and the paper 3 is released by lowering the mounting plate 5, the paper is not fed in duplicate after the pressure contact of the reversing roller 2 is released.

In the above embodiment, the present invention was applied to a bypass paper feed device of a copying machine, but the present invention can be applied to all other paper feed devices that require a copy machine, and the present invention can be applied in the same manner as in the above embodiment. It has the effect of

〔Effect of the invention〕

As described above, according to the present invention, each time the feeding of one sheet of paper is completed, the mounting plate on which the paper is placed is lowered to release the pressure contact between the paper and the paper feed roller, and the By using the lowering mechanism of the loading plate, the pressure contact between the pair of paper feed rollers is released every time one sheet of paper is fed, so paper can be easily removed by simply adding a simple component to the conventional paper feeding device. It is possible to realize a pressure contact release mechanism for the pair of paper feed rollers that does not cause double feeding, and when applied to an image forming apparatus, it is possible to prevent deterioration of image quality due to pressure contact between the pair of paper feed rollers.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a paper feeding device according to an embodiment of the present invention, FIG. 2 is a diagram showing a state in which the pressure contact between a pair of paper feeding rollers in the device is released, and FIG. 3 is a diagram showing the lowering of paper in the device. It is a perspective view for explaining a mechanism. l... Paper feed roller, 2... Reversing roller, 3... Paper, 4... Paper feeding roller, 5... Mounting plate, 6... Riding plate lowering mechanism, 8... - Pressure release member. Patent applicant: Representative of Mita Kogyo Co., Ltd. Patent attorney: Yukio Ono Figure 2

Claims (1)

[Claims] (1) A paper feed roller pair consisting of a paper feed roller and a reversing roller for preventing double feeding, which are pressed against each other during paper feeding, and the paper on the mounting board are pressed against each other, and the paper is conveyed to the paper feed roller pair. The paper feeding device has a paper feeding roller for feeding the paper, and the mounting plate is lowered to release the pressure contact between the paper and the paper feeding roller each time the feeding of one sheet of paper is completed. A pressure release member is provided which is connected to the lowering mechanism of the mounting plate to release the pressure contact between the paper feed roller pair, and each time the feeding operation of one sheet of paper is completed, the mounting plate is lowered. A paper feeding device characterized in that the pressing release member is operated using a lowering mechanism to release the pressure contact between the pair of paper feeding rollers.