JP2001341861A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device capable of stably feeding the paper without affecting the rotation of a paper feeding roller even when a paper sheet on a paper feeding table is waved. SOLUTION: A paper feeding gear 3 is mounted on one end part 4 of a shaft 4 rotatably along with the shaft 4, and half moon-shaped paper feeding rollers 5 are mounted on two intermediate parts of the shaft 4 at positions capable of feeding the paper sheet S on the paper feeding table 6, rotatably along with the shaft 4. Collars 52 are respectively mounted near the two paper feeding rollers 5, the collars 52 are projected from flat parts 51 of the paper feeding rollers 5 as shown in a drawing 2, which prevents a surface of the paper sheet S from being kept into contact with the flat part 51. The collars 52 are rotatable and slidable with the shaft 4, and mounted by means of fasteners 53 unmovably in the axial direction of the shaft 4.

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 in an image forming apparatus such as a copying machine, a facsimile machine, and a printer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile machine, a printer, etc., there is known a paper feeder for feeding sheet paper using a half-moon-shaped feed roller as shown in FIG. This type of paper feeder transmits the rotation of the drive motor 1 to the paper feed gear 3 via a plurality of idle gears 2 and gives rotation to a half-moon-shaped paper feed roller 5 coaxial with the paper feed gear 3. Thus, sheet paper is fed.

More specifically, referring to FIG. 5, the outer peripheral surface of the feed gear 3 has a tooth portion 31 and a toothless portion 32, and one end surface of the feed gear 3 has a projection. 33 and a rotation preventing unit 34 are provided. One end of a spring 35 as an urging means is attached to the projection 33, and urges the paper feed gear 3 to rotate clockwise. The rotation preventing member 34 is configured to engage the lever 37 attached to the solenoid 36 to prevent the rotation of the feed gear against the urging force of the spring 35.

In the above-described configuration, in the non-sheet feeding state, the toothless portion 32 of the sheet feeding gear 3 is located at a position facing the teeth of the idle gear 23 as shown in FIG. Is not transmitted to the paper feed roller 5.

Here, when there is a paper feed command by, for example, turning on a print key (not shown) or the like, the solenoid 36 is turned on, whereby the engagement between the lever 37 and the rotation preventing section 34 is released. As a result, the urging force of the spring 35 acts, the paper feed gear 3 rotates clockwise, and the teeth of the idle gear 23 and the teeth 31 of the paper feed gear 3 mesh, so that the driving force from the drive motor 1 is reduced. This is transmitted to the paper feed roller 5. Thereby, the paper feed roller 5 rotates to feed the sheet paper. When the paper feed roller 5 makes one rotation, the toothless portion 32 comes to a position facing the teeth of the idle gear 23 as shown in FIG. At this time, the solenoid 36 is turned off, and the drive from the drive motor 1 is cut off again.

[0006]

In the prior art as described above, when the sheet S is wavy as shown in FIG. 6, the sheet S comes into contact with the flat portion 51 of the sheet feeding roller 5. As a result, the tension force of the spring 35 is given a resistance. Therefore, even when the solenoid 36 is turned on during the sheet feeding operation and the engagement between the lever 37 and the rotation preventing portion 34 is released, the sheet feeding gear 3 does not rotate, and a problem such as a sheet feeding failure may occur.

[0007] A similar problem also occurs when sheets S exceeding the allowable number are set in the sheet feeding section as shown in FIG.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a sheet feeding device for performing stable sheet feeding.

[0009]

According to a first aspect of the present invention, there is provided a sheet feeding apparatus which is attached to a drive source and a shaft which is rotated by receiving a drive from the drive source, and which feeds sheet paper. A half-moon-shaped paper feed roller, a paper feed gear attached to one end of the shaft, and having a toothless portion for interrupting drive from the drive source and a tooth portion for transmitting drive from the drive source. At least one intermediate gear exists between the driving source and the sheet feeding gear, and the teeth of the sheet feeding gear mesh with the intermediate gear to transmit the drive from the driving source to the sheet feeding roller. And biasing means for biasing the sheet feeding gear to rotate about the shaft, and rotation preventing means for preventing rotation of the sheet feeding gear against the biasing force of the biasing means. In the non-feeding state, the gap between the toothless portion of the feeding gear and the intermediate gear is caused by the engagement between the feeding gear and the rotation preventing means. The sheet feeding gear is held at the second position, and the sheet feeding gear and the rotation preventing means are disengaged with the sheet feeding start operation, and the sheet feeding gear is moved to the second position by the urging force of the urging means. 1 and then rotate the paper feed gear once by drive transmission from a drive source to feed the sheet paper through the paper feed roller. A collar protruding from a flat portion of the paper feed roller is provided near the paper feed roller. According to the first aspect of the present invention, since the collar protruding from the flat portion of the sheet feeding roller is provided, even if the sheet set in the sheet feeding portion is wavy, the sheet is fed. There is no hindrance to the rotation of the paper feed roller during the start operation. Further, it is possible to prevent the sheet sheets exceeding the allowable number from being set in the sheet feeding unit, and it is possible to perform stable sheet feeding.

The paper feeder according to claim 2 is the paper feeder according to claim 1, wherein the shaft of the paper feed roller and the collar are slidable in a rotating direction. According to the second aspect of the present invention, since the collar is slidable in the rotating direction, the resistance between the sheet paper and the collar is further reduced, and more stable paper feeding is possible.

According to a third aspect of the present invention, in the sheet feeding apparatus, the shaft of the sheet feeding roller and the collar rotate in conjunction with each other, and the surface material of the collar has a lower resistivity than the surface material of the sheet feeding roller. The sheet feeding device according to claim 1, wherein: According to the third aspect of the present invention, since the surface material of the color is made to have a low resistivity, the resistance between the sheet paper and the color is further reduced, and more stable paper feeding is possible.

[0012]

FIG. 1 is a schematic perspective view of an embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 1 includes a drive motor 1, an idle gear 2 as an intermediate gear, a paper feed gear 3, and a half-moon-shaped paper feed roller 5 provided coaxially with the paper feed gear 3. It is mainly composed. The idle gear 2 includes a gear 21 attached to a tip end of a drive shaft of the drive motor 1 and the gear 2.
1 and a gear 23 that meshes with the gear 22
And has the function of transmitting the driving force of the driving motor 1 to the sheet feeding gear 3.

As shown in FIG. 5, the sheet feeding gear 3 has an outer peripheral surface formed of a toothed portion 31 and a toothless portion 32, and a projection 33, a rotation preventing portion 34 Is provided. One end of a spring 35 as an urging means is attached to the projection 33, and the other end of the spring 35 is attached to an image forming apparatus main body (not shown), thereby rotating the paper feed gear 3 clockwise. It is energizing. The rotation preventing member 34 is configured to prevent rotation of the sheet feeding gear 3 against the urging force of the spring 35 by engaging with a lever 37 attached to a solenoid 36. That is, the sheet feeding gear 3 is located at the second position in the non-sheet feeding state as shown in FIG. 5 and the teeth 31 of the sheet feeding gear 3 as shown in FIG.
And a first position at which the gear 23 meshes with the solenoid 36.
Is displaced by ON / OFF of.

The paper feed gear 3 is attached to one end of the shaft 4 so as to rotate together with the shaft 4, and can feed the sheet S on the paper feed table 6 at two intermediate portions of the shaft 4. At the position, a half-moon-shaped paper feed roller 5 is attached so as to rotate with the shaft 4. Colors 52 are provided in the vicinity of the two paper feed rollers 5, respectively.
2 protrudes from the flat portion 51 of the sheet feeding roller 5 so that the surface of the sheet S does not contact the flat portion 51. The flat portion 51 of the collar 52
The amount of protrusion from the paper feed roller 5 is preferably about 3 mm to a range smaller than the arc of the outer periphery of the paper feed roller 5, but is a range that protrudes from the flat portion 51 and does not exceed the arc of the outer periphery of the paper feed roller 5. If so, it can be appropriately selected.

The collar 52 is slidable with respect to the shaft 4 in the direction of rotation, and is attached by a stopper (not shown) so as not to move in the axial direction of the shaft 4. The material of the outer peripheral surface of the paper feed roller 5 is a material having a large frictional force with the sheet paper such as EPDM, that is, a material having a high resistivity, and the material of the outer peripheral surface of the collar 52 is a sheet paper such as polyacetal or the like. Is low, that is, made of a material having a low resistivity.

Next, the operation of the above embodiment will be described. As described above, in the non-sheet feeding state, the sheet feeding gear 3 is at the second position as shown in FIG. Here, for example, when a paper feed command is issued by turning on a print key (not shown) or the like, the solenoid 36 is turned on, whereby the engagement between the lever 37 and the rotation preventing unit 34 is released as shown in FIG. As a result, the urging force of the spring 35 acts, the paper feed gear 3 rotates clockwise, and the teeth of the idle gear 23 and the teeth 31 of the paper feed gear 3 mesh with each other, so that the driving force from the drive motor 1 is reduced. This is transmitted to the paper feed roller 5. As a result, the paper feed roller 5 rotates to feed the sheet S on the paper feed table 6.

At this time, even if the sheet S on the sheet supply table 6 is wavy, the surface of the sheet S is in contact with the collar 52 as shown in FIG. The contact with the portion 51 can be prevented. The collar 52
Is slidable in the direction of rotation with the shaft 4 and is made of a material having a low resistivity, such as EPDM, so that the rotation of the paper feed roller 5 is smoothly performed, and thus the paper feed gear 3 is moved from the second position to the second position. 1 can be reliably displaced to the position 1, and the sheet feeding is stabilized. When the paper feed roller 5 makes one rotation, the toothless portion 32 comes to a position facing the teeth of the idle gear 23 as shown in FIG. At this time, the solenoid 36 is turned off, and the drive from the drive motor 1 is cut off again.

The timing of turning the solenoid 36 from ON to OFF is performed immediately after the paper feed gear 3 reaches the first position.
Any timing is acceptable as long as the missing tooth portion 32 of the paper feed gear 3 reaches the position facing the teeth of the gear 23 again.

The above is one embodiment of the present invention, and the present invention can be implemented without departing from the present invention. For example, the collar 52 may not be rotatable and slidable with respect to the shaft 4 but may rotate with the shaft 4. Further, the paper feed roller 5 may be made of a material other than the above-described materials as long as the material has a high resistivity enough to convey the sheet paper by frictional force. Further, since the collar 52 only needs to protrude beyond the flat portion 51 of the paper feed roller 5, it may be made of a material other than the above-described materials. Further, the shape of the collar 52 is not limited to the shape of the donut (both the inner and outer peripheral surfaces are circles) shown in the above embodiment, but protrudes from the flat portion 51 of the paper feed roller 5. Any shape may be used.

[0020]

As described above, according to the present invention,
Providing the collar enables stable paper feeding.

[0021]

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of the present invention.

FIG. 2 is a partial view showing one embodiment of the present invention.

FIG. 3 is a diagram showing a first state in the present invention.

FIG. 4 is a schematic perspective view showing a conventional sheet feeding device.

FIG. 5 is a partial view showing a sheet feeding device (a diagram showing a second state in the present invention).

FIG. 6 is a partial view showing a conventional sheet feeding device when a corrugated sheet is set.

FIG. 7 is a partial view showing the conventional sheet feeding device when sheets exceeding the allowable number are set.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drive motor 2 ... Idle gear 3 ... Feeding gear 31 ... Tooth part 32 ... Missing tooth part 4 ... Shaft 5 ... Feeding roller 51 ... Flat part 52 ... Color 6 ... Feeding board S ... Sheet paper

Claims (3)

[Claims] 1. A driving source, a half-moon-shaped feeding roller for feeding sheet paper attached to a shaft to which driving is transmitted from the driving source and rotating, and attached to one end of the shaft, A sheet feeding gear having a toothless portion for interrupting driving from the driving source and a tooth portion for transmitting driving from the driving source; and at least one intermediate gear between the driving source and the sheet feeding gear And the teeth of the paper feed gear mesh with the intermediate gear to urge the paper feed gear about the shaft to the first position where the drive from the drive source is transmitted to the paper feed roller. An urging means; and a rotation preventing means for preventing the rotation of the sheet feeding gear against the urging force of the urging means. By the engagement, the sheet feeding gear is held at the second position where the toothless portion of the sheet feeding gear and the intermediate gear face each other, and the sheet feeding start operation is started. The engagement between the sheet feeding gear and the rotation preventing means is released, and the sheet feeding gear is moved to the first position by the urging force of the urging means. Is rotated once, and the sheet is fed through the feed roller. In the feed device, the feed roller is coaxial with the feed roller and protrudes from the flat portion of the feed roller in the vicinity of the feed roller. A paper feeding device characterized by having a collar. 2. The sheet feeding device according to claim 1, wherein the shaft of the sheet feeding roller and the collar are slidable in a rotating direction. 3. The paper feed roller according to claim 1, wherein the shaft of the paper feed roller and the collar rotate in conjunction with each other, and the surface material of the collar has a lower resistivity than the surface material of the paper feed roller. A paper feeder according to claim 1.