JPH0735439U - Sheet material feeder - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent an irregular state in which the next sheet material is generated when the sheets are sequentially taken out from the uppermost sheet material of the superimposed sheet material. A load control member and an elastic member for elastically deforming when the feeding roller is driven and for reversing the roller when returning to the old position by stopping driving are arranged.

Description

[Detailed description of the device]

[0001]

[The purpose of the device]

 The present invention relates to a sheet material feeding device in which sheets are taken out one by one from the uppermost one of the stacked sheet materials.

Such a feeding device has been already proposed, for example, as disclosed in Japanese Patent Publication No. 1-57011, and will be briefly described below.

FIG. 2 is a perspective view showing an example of such a sheet material feeding device, showing a means for feeding a transfer sheet of a copying machine. The copying machine main body shown by a chain double-dashed line is shown in FIG. When the cassette b in which the transfer paper e, which is a sheet material, is superposed and stored is mounted, the vicinity of the leading end of the transfer paper e comes into contact with the feeding roller M arranged on the shaft m arranged on the mounting body side.

When the shaft m is driven in this state, the feeding roller M takes out the uppermost transfer sheet in the cassette beyond the separation claw a provided at the front end of the cassette and conveys it to the conveyance roller pair g. Further, it is conveyed to a well-known image forming site.

In such a sheet material take-out means, as shown in FIG. 3, since the feeding roller M is in contact with the transfer sheet with an appropriate nip width f, the sheet feeding roller is the first sheet. At the last portion of the sheet material e-1, this portion comes into contact with the leading edge portion of the second sheet material e-2 at the same time, and contacts the sheet feeding roller M in the ranges of f-2 and f-1, respectively. I will come into contact with you.

By this time, since the first sheet has been pulled by the conveying roller pair g on the downstream side, if the frictional force of the f-2 portion is large, the roller M will receive a rotational force, As a result, the second sheet material is sent out by the frictional force of the f-1 portion, so that the sheet material can be bent as indicated by the symbol 1 in FIG.

When such bending occurs, there is a possibility that a bending tendency is attached to cause a transfer failure or cause a jam. Therefore, in order to solve such a problem, for example, the one disclosed in Japanese Patent Publication No. 1-57011 has been proposed.

FIG. 4 shows the paper feed roller described in the above publication, which is mounted on the shaft m of the apparatus as shown in FIG. It is in contact with the sheet e. The roller M comprises a roller inner ring c made of a rigid material and rotatably arranged on a shaft m, and an outer ring ma made of rubber or the like arranged around the roller inner ring c. When the roller M comes into contact with the uppermost sheet of the sheet material, which is the object to be conveyed, and rotates in the direction of arrow B in the drawing, the uppermost sheet in the sheet material storage portion that comes into contact with the roller M moves in the direction of arrow A. Will be transported to.

That is, an opening ca is formed in the inner ring c, and a pin n fixed to the shaft m is arranged inside the opening ca. A spring i is provided in the opening ca. One end of the spring i abuts on the edge of the opening ca and the other end abuts on the pin n so that the spring i It is biased to the edge portion cb.

With such a structure, when the shaft m rotates in the direction of arrow B, the pin n attached to this presses the edge portion cb of the opening ca and the entire roller M in the direction of arrow B. The sheet material that rotates and contacts the sheet is conveyed in the direction of arrow A.

When the conveyed sheet material is gripped and pulled by a conveying roller pair (not shown) arranged on the downstream side (right side in the drawing), the rotating force to the roller M is also blocked by a clutch (not shown). Then, the axis m stops. At this time, since the roller continues to rotate due to the frictional force between the sheet material and the roller M, the pin n integrated with the stopped shaft m is separated from the edge cb of the opening, and the spring i is compressed. The roller M continues to rotate until the spring force and the friction force conflict with each other.

Even when the state shown in FIG. 3 occurs and the tip of the sheet material is bent, when the first sheet material passes and the torque to the feeding roller M disappears, Since the restoring force of the spring i, which has been compressed up to that point, causes the roller M to rotate a little in the reverse direction, the sheet material moves in the opposite direction, and the bending is eliminated.

In the meantime, in the above configuration, when the roller M is reversely rotated by the restoring force of the spring i, the shaft m and the pin n integral with the shaft m must be braked to be in a fixed state. I can't do it. Further, while the sheet material is being transported by the transportation means such as the transportation roller g on the downstream side, the roller M needs to be smoothly driven as the sheet material travels.

As described above, it is extremely difficult to balance the above-mentioned braking action on the roller M and the force for reversing, and it has not been possible to achieve a satisfactory result. Is the reality.

The present invention has been made to cope with such a situation, and has a very simple structure in a sheet material feeding device that sequentially takes out the sheets one by one from the uppermost one of the superimposed sheets. It is an object of the present invention to provide a device that can reliably prevent the conveyance of the first sheet and the bending of the second and subsequent sheets without the need for production and adjustment.

[0016]

[Constitution of device] [Technical means for solving the problem and its action]

 In order to achieve the above object, the present invention conveys a sheet material in a sheet material feeding device in which a roller is brought into contact with the superposed sheet material and the roller is driven to sequentially convey and discharge the sheet material. After the end of driving the paper feed roller in the direction, the means for reversing the paper feed roller by a predetermined amount is provided, or the means for reversing the paper feed roller in this device is a paper feed roller. A sheet material feeding device comprising: a load control member attached to a drive shaft of a roller; and an elastic member that elastically deforms as the paper feeding roller rotates in the conveying direction. .

With this structure, the sheet material can be sequentially and reliably taken out from the uppermost one of the superposed sheet materials with no difficulty in manufacturing or adjustment due to an extremely simple structure. Is possible.

[0018]

[Explanation of Examples]

 FIG. 1 is a perspective view showing the embodiment of the present invention, in which a sheet e loaded in a cassette b is attached to a shaft m driven by a drive source (not shown) and is shown at the top. The roller M that contacts the sheet conveys and discharges the sheet to the right in the drawing. In each part, the parts corresponding to those shown in FIG. 2 are designated by the same reference numerals.

In the illustrated apparatus, the paper feed roller Ma is fixed to the shaft m, and the uppermost sheet in the cassette is taken out by rotating the paper feed roller Ma.

One end of the shaft m is extended outward, and a load control member h that rotates with a predetermined load torque is attached to a suitable position of the end of the shaft m. An appropriate elastic member i is provided. The elastic member i is engaged with a fixed portion j in the apparatus main body.

With such a configuration, when the shaft m is driven and rotates together with the paper feed roller ma, the sheet e is conveyed, and the load control member h also rotates to engage the fixed portion at a proper position. The elastic member i to be joined is elastically deformed. Due to the reaction force at this time, a force in the reverse rotation direction is applied to the load control member h. In this case, it is assumed that the load torque of the load control member h is set to be smaller than the drive torque of the shaft m.

Therefore, only the shaft m rotates when the reaction force and the load torque are in equilibrium, and when the rotational force of the shaft m then stops, the force balance is lost, and the reaction force causes the shaft m and The paper feed roller Ma rotates in the reverse direction until the elastic deformation of the elastic member i returns to its original state. When the sheet is pulled by the pair of conveying rollers located on the downstream side, the sheet feeding roller is rotated by this, and the elastic member is deformed in the same manner as described above. The paper feed roller reverses until it is fixed.

[0023]

[Effect of device]

 As described above, according to the present invention, when the rollers are sequentially taken out from the uppermost sheet while the leading end portions of the overlapped sheet materials are suppressed by means such as a separating claw, the first and second rollers are used. It is possible to reliably prevent the irregular state of the second sheet caused by engaging with both the first sheet with a simple configuration and without requiring particularly troublesome adjustment.

Therefore, by using the present invention in a sheet feeding device of an image forming apparatus such as a copying machine, there is a remarkable effect in preventing the occurrence of transfer failure and jam.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of an embodiment in which the present invention is applied when a sheet material is taken out from a cassette used in an image forming apparatus.

FIG. 2 is a perspective view of an essential part showing a sheet takeout mechanism of a known image forming apparatus.

FIG. 3 is an explanatory diagram showing a state in which the last edge of the uppermost sheet of the superposed sheets touches the sheet feeding roller.

FIG. 4 is a side view showing a configuration of a known paper feed roller for solving the problem caused by the state shown in FIG.

[Explanation of symbols]

 a separation claw b cassette e sheet material h load control member i elastic member Ma, M paper feed roller l bending of sheet material

Claims (2)

[Scope of utility model registration request] 1. A roller is brought into contact with the superposed sheet materials,
In a sheet material feeding device that drives the rollers to sequentially convey and discharge the sheet material, provided with means for reversing the sheet feeding roller by a predetermined amount after the driving of the sheet feeding roller in the sheet material conveying direction is completed. A sheet material feeding device characterized in that 2. A means for reversing the paper feed roller comprises a load control member attached to a drive shaft of the paper feed roller, and an elastic member elastically deformed as the paper feed roller rotates in the conveying direction. The sheet material feeding device according to claim 1.