JPH09290936A - Paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely correct the skew of the transfer paper with smaller number of parts. SOLUTION: A pair of carrying rollers 9, 9 are provided between a transfer paper shuffling device comprising a paper sheet feed roller, etc., and a resist roller. When the transfer paper is normally carried, the load on a pair of carrying rollers 9, 9 is same, planetary gears 12, 12 are not rotated, right and left carrying rollers 9 are rotated at the same number of revolution to carry the transfer paper. When the transfer paper is skewed, one end is abutted on the resist roller, and the transfer paper is no longer advanced, the planetary gear 12 starts its rotation, the rotation of an input gear 11 is transmitted only to the carrying roller 9 on the reverse side, and the skew of the transfer paper is corrected by adjusting the number of' revolution of the right and left carrying rollers 9 until each end of the transfer paper P is abutted on the resist roller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for an image forming apparatus such as a copying machine and a printer.

[0002]

2. Description of the Related Art A sheet feeding device for feeding a sheet using a transfer sheet conveying member such as a calling roller and a transfer sheet separating device at a sheet feeding portion of a sheet feeding tray is disclosed in, for example, Japanese Patent Laid-Open No. As disclosed in Japanese Patent Publication No. 01-317938, by providing a pair of pick rollers, one of which is independently driven when the skew of the cut sheet is detected, the skew of the sheet can be easily and accurately corrected. There are things that I was able to do.

However, in the paper feeding device disclosed in Japanese Patent Laid-Open No. 1-317938, since a clutch, two motors, a sensor, etc. must be used, the structure and control are complicated and the cost is high. is there.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet feeding device capable of surely correcting the skew of a transfer sheet with a structure having a smaller number of parts. It is another object of the present invention to provide a sheet feeding device that can prevent double feeding of sheets and can reliably correct the skew of one transfer sheet. Another object of the present invention is to provide a paper feeding device capable of suppressing the generation of wrinkles during the transfer of the transfer paper.

[0005]

In order to achieve the above-mentioned object, a sheet feeding device of the present invention has a transfer sheet conveying member such as a calling roller in a sheet feeding section of a sheet feeding tray. In a paper feeding device that feeds out paper using the transfer paper separating device, a pair of carrying rollers is provided, and the pair of carrying rollers are connected by a differential gear device.

A second aspect of the present invention is characterized in that a pair of conveying rollers connected by the differential gear device are located between the transfer paper separating device and the registration roller.

According to the third aspect of the present invention, the axis lines of the pair of conveying rollers connected by the differential gear device have a receding angle with respect to the sheet conveying direction and are arranged symmetrically with respect to the sheet conveying direction. It is characterized by being done.

According to the fourth aspect of the present invention, after the sheet enters the pair of conveying rollers connected by the differential gear device, the calling roller and the like are stopped, and only the pair of conveying rollers is used. A feature is that the paper is conveyed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a side sectional view showing an embodiment of a sheet feeding device according to the present invention, FIG. 2 is a perspective view of a sheet feeding mechanism, and FIG. 3 is a perspective view of the same operating state. In the drawing, 1 is a manual feed table, 2 is a paper feed roller, 3 is a paper feed clutch, 4 is a call roller, 5 is a reverse rotation roller having a built-in torque limiter 6, and 7 is a pickup solenoid. The transfer paper P is set so as to abut against a roller on the manual feed table 1.

In this mechanism, each element below the paper feed roller 2 constitutes a transfer paper separating device. When the paper feed clutch 3 rotates, the shaft of the paper feed roller 2 rotates and the paper feed roller 2 is driven. Being rotated. Further, the calling roller 4 is also driven and rotated via the relay gear group. Further, the reverse rotation roller 5 that is in contact with the paper feed roller 2 is caused by the frictional force with the paper feed roller 2 that exceeds the torque of the built-in torque limiter 6 and the paper feed roller 2
And go around. At the paper feed timing, the pickup solenoid 7 is turned on, and the calling roller 4 is lowered through the link mechanism to feed the transfer paper P.

Further, the apparatus of this embodiment is provided with a pair of conveying rollers 9, 9 between a transfer paper separating device composed of a paper feed roller 2 and the like and a registration roller 8. These transport rollers 9, 9 are connected via a differential gear device. As shown in FIGS. 4 and 5, the differential gear device includes an input gear 11 that meshes with a gear 10 transmitted from a drive source and receives a rotation, and a pair of bevel gears having a rotation shaft in a direction perpendicular to the rotation shaft. The planetary gears 12 and 12 are shaped, and the transmission gears 14 and 14 are bevel gears that mesh with the planetary gears 12 to transmit the rotation to the drive shaft 13 of each conveying roller 9. Further, the two conveying rollers 9 and 9 are the transmission gears 1 of the differential gear device described above.
Although it is driven from 4 via a gear train, it is arranged so as to have the same angle opened in the left-right direction by 90 ° or more with respect to the traveling direction of the transfer paper P (the direction of the arrow in FIG. 4).

The operation of the apparatus of this embodiment will be described below. First, the separation of the transfer paper P at the time of paper feeding is performed as follows. The torque limiter 6 built in the reverse rotation roller 5 during normal single-sheet feeding
The feeding force (friction force) of the paper feed roller 2 is sent to the registration rollers 8 rather than the torque force of the above. Therefore, the reverse rotation roller 5 rotates together with the transfer paper P due to the frictional force. That is, the feeding force F applied by the paper feed roller 2 to the first transfer paper P
There is a relation of FI> F2 + F3 between the friction resistance force F2 between the transfer sheets P and the returning force F3 of the torque limiter 6 (see FIG. 6).

When two or more transfer sheets P are fed, since the frictional force between the transfer sheets P is small, the rotation of the feed roller 2 is transmitted to the uppermost transfer sheet P, but the lower side. Transfer paper P
Is hardly communicated. Accordingly, the rotation of the reverse rotation roller 5 from the torque limiter 6 is transmitted, and a force acts in a direction to return the lower transfer paper P to the paper feed table 1. At this time, the return force F3 of the torque limiter 6, the feeding force F4 given to the second transfer sheet P by the first transfer sheet P, and the return resistance force F5 and F6 between the transfer sheets P are F3. The relationship of> F4 + F5 = F6 is established (see FIG. 7).

The transfer sheet P which has been conveyed one sheet as described above is then gripped by the conveying roller 9. Transfer paper P
When the paper is gripped by the carrying roller 9, the paper feeding clutch 3 is turned off, the driving of the paper feeding roller 2 and the calling roller 4 is cut off, and thus the transfer paper P is carried by only the carrying roller 9. At this time, the feeding roller 2 and the calling roller 4 may be rotated together with the transfer sheet P, or may be slipped while being stopped.

The front end of the transfer paper P that has passed through the transport roller 9 is
Next, it hits the registration roller 8. At this time, the transfer paper P
Is skewed, either the right end or the left end of the front end of the transfer paper P hits the registration roller 8 first. At this time, the conveying roller 9 on the side that has previously abutted against the registration roller 8 is stopped by resistance, but the conveying roller 9 on the opposite side continues to rotate by the differential mechanism. By this operation, the left and right ends are at the same position with respect to the registration rollers, and the skew is corrected.

The operation of this differential gear device will be described. The rotation transmitted from the drive source is transmitted to the input gear 11 via the gear 10. Here, when the load applied to both the conveyance rollers 9 is the same, the planetary gears 12 and 12 attached to the input gear 10 do not rotate, and the left and right conveyance rollers 9 rotate at the same speed as the rotation speed of the input gear 10. Rotate by number. Next, when the transfer sheet P is skewed and conveyed, and any one of the left and right ends of the transfer sheet tip comes into contact with the registration roller first, the transfer sheet P cannot advance further on the abutting side, so the conveyance roller 9 also stops. To do. At this time, the planetary gear 12 starts to rotate, and the rotation of the input gear 11 is transmitted only to the opposite transport roller 9, and the rotational speeds of the left and right transport rollers 9 are adjusted until both ends of the transfer sheet P hit the registration rollers 8. To do. The skew of the transfer sheet is corrected by this series of operations.

Further, as described above, the two conveying rollers 9 have the same angle of 90 ° or more with respect to the moving direction of the transfer sheet P, and the angle formed by both conveying rollers 9 is 180 ° or more. Therefore, when the transfer sheet P is conveyed, a force pulling it to the left and right is applied, and wrinkles are less likely to occur.

[0018]

As described above, in the paper feeding device according to the first aspect of the present invention, by connecting the pair of conveying rollers with the differential gear device, the skew of the transfer paper can be reliably achieved with a structure having a small number of parts. There is an effect that it becomes possible to correct.

In the paper feeding device of the second aspect, by providing the paired conveying rollers between the transfer paper separating device and the registration roller, in addition to the above-mentioned common effect, double feeding of the paper is prevented to ensure the reliability. Moreover, there is an effect that the skew of one transfer sheet can be corrected.

In the paper feeding device according to the third aspect of the present invention, the pair of conveying rollers are provided with a receding angle with respect to the sheet conveying direction. There is an effect that it becomes possible to suppress.

In the sheet feeding device according to the present invention, after the sheet has entered the position of the pair of conveying rollers, the sheet is conveyed only by the conveying rollers, so that in addition to the above common effect, the skew is surely achieved. There is an effect that it becomes possible to perform the correction.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a sheet feeding device according to the present invention.

FIG. 2 is a perspective view of a paper feed mechanism of the apparatus of the embodiment shown in FIG.

FIG. 3 is a perspective view of the same operation state.

FIG. 4 is a plan view showing the conveying roller and a differential gear device.

FIG. 5 is a side view of the same.

FIG. 6 is a side view for explaining a force relationship between a paper feed roller, a reverse rotation roller, and a torque limiter during the normal single-sheet feeding.

FIG. 7 is a side view for explaining a force relationship among a paper feed roller, a reverse rotation roller, and a torque limiter when feeding the same two sheets.

[Explanation of symbols]

 1 Manual Feed Table 2 Paper Feed Roller 3 Paper Feed Clutch 4 Calling Roller 5 Reversing Roller 6 Torque Limiter 7 Pickup Solenoid 8 Registration Roller 9 Transport Roller 10 Gear 11 Input Gear 12 Planetary Gear 13 Transport Roller Drive Shaft 14 Transmission Gear P Transfer Paper

Claims (4)

[Claims] 1. A sheet feeding device for feeding a sheet using a transfer sheet conveying member such as a calling roller and a transfer sheet separating device at a sheet feeding portion of a sheet feeding tray, and having a pair of conveying rollers,
A paper feeding device, characterized in that the pair of conveying rollers are connected by a differential gear device. 2. The sheet feeding device according to claim 1, wherein a pair of conveying rollers connected by the differential gear device are located between the transfer sheet separating device and the registration roller. 3. An axis line of a pair of conveying rollers connected by the differential gear device has a receding angle with respect to the sheet conveying direction and is arranged symmetrically with respect to the sheet conveying direction. The sheet feeding device according to claim 1 or 2. 4. After the sheet has entered the pair of conveying rollers connected by the differential gear device, the calling roller or the like is stopped and the sheet is conveyed only by the pair of conveying rollers. The sheet feeding device according to claim 2 or 3.