JPH06247567A - Paper sheet feed device - Google Patents

Abstract

PURPOSE:To feed paper sheets under the condition in which contact pressure between a paper feed roller and a paper sheet is set constant. CONSTITUTION:Lifting force is applied on paper sheets 10 piled on a push-up plate 12 by means of push-up springs 15 as an energization means of the push-up plate interposed between the push-up plate 12 and a case 11. The lifting force is regulated by means of a regulating roller 20 arranged in the vicinity of a paper sheet feed roller 30, so that the uppermost paper sheet is always positioned at a fixed height position. Meanwhile, the paper sheet feed roller 30 is brought in contact with the paper sheet 10 at fixed pressure by the energization force of a spring 35 or the dead weight, and the paper sheet fed roller 30 is rotated under this condition so as to feed the paper sheet.

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 of an image forming apparatus in, for example, a word processor, a copying machine, etc., and in particular, it is stable regardless of the type and thickness of a large number of sheets stacked. The present invention relates to a paper feeding device capable of feeding paper.

[0002]

2. Description of the Related Art A conventional sheet feeding device, particularly in the case of a small image forming apparatus, urges a push-up plate on which sheets are stacked toward a sheet feeding roller through urging means such as a spring. A structure is known in which a sheet is pressed against a sheet feeding roller arranged at a fixed position (for example, Japanese Patent Laid-Open No. 2-7).
No. 0628, 70629).

Further, in an image forming apparatus that feeds a large amount of paper such as a large-sized copying machine, a motor pushes up a push-up plate on which paper is loaded, and a sensor detects the position of the uppermost paper to detect the paper. A structure is known in which a predetermined control is performed so that the position is constant, and a paper feed roller movably provided in the vertical direction is pressed against the paper with a constant pressure (for example, Japanese Patent Laid-Open No. 63-11233). Gazette).

Further, the one in which the above-mentioned mechanism described in Japanese Patent Laid-Open No. 63-11233 is omitted is Japanese Patent Laid-Open No. 61-197.
It has been known for a long time in Japanese Patent No. 338.

[0005]

However, in the paper feeding apparatus described in Japanese Patent Laid-Open No. 2-70628 in which the paper is pressed against the paper feeding roller by the urging force of the spring, the paper is fed depending on the type and thickness of the paper. Since the weights are different, the pressure generated between the paper feed roller and the paper is variously changed, and there is a disadvantage that a paper feed error or a double feed is caused due to the pressure.

Further, in the paper feeding apparatus described in Japanese Patent Laid-Open No. 63-11233, in which the motor raises the paper, the uppermost paper position is detected by the sensor, and this is controlled to a fixed position, the motor is Since the structure requires separate parts such as a sensor, the internal structure of the device is complicated,
There is an inconvenience that not only the size is increased, but also the cost is increased and the power consumption is wasted.

Further, in the one disclosed in Japanese Patent Laid-Open No. 61-197338, since the entire sheet is held down by the lifting restraint plate,
If there is a large amount of paper loaded, the sliding friction between the lifting restraint plate and the topmost paper will be large, and in order to overcome this and send the paper out, the drive source of the paper feed roller must be made larger than necessary. There was an inconvenience that it did not happen.

[0008]

OBJECTS OF THE INVENTION The object of the present invention is to improve the disadvantages of the conventional example, and in particular, the uppermost sheet of paper is kept at a constant pressure on the feed roller regardless of the type of sheets stacked on the lifting plate. It is an object of the present invention to provide a sheet feeding device that can be brought into contact with each other and can reduce cost while avoiding complication of the internal structure of the device.

[0009]

The present invention comprises a push-up plate on which a plurality of sheets are stacked, and a push-up plate biasing means for biasing the push-up plate toward the paper feed roller. In the sheet feeding device provided with the uppermost sheet abutting the sheet feeding roller by the urging force and capable of feeding a predetermined sheet,
A regulation roller that comes into contact with the uppermost sheet and maintains a constant contact pressure between the sheet feeding roller and the sheet is provided in the vicinity of the sheet feeding roller.
This is intended to achieve the above-mentioned object.

[0010]

According to the present invention, the paper is constantly urged toward the paper feed roller by the urging means, but the paper is fed in a state where the vertical position of the paper is maintained at a constant position by the regulating roller provided along with the paper feed roller. It comes into contact with the paper roller. Therefore, the pressure generated between the paper feed roller and the paper is always constant, and a constant paper feed performance is ensured regardless of the type of paper.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sheet feeding device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of the sheet feeding device in this embodiment. In this figure, a plate-shaped push-up plate 12 is vertically movably housed in a box-shaped case 11 formed to accommodate a large number of single-cut sheets 10. A large number of sheets 10 are stacked on the upper surface of the push-up plate 12, and between the push-up plate 12 and the bottom plate 11A of the case 11, a coil-like push-up as a push-up plate urging means is performed. Two springs 15 are provided so that the push-up plate 12 and thus the paper 10 are constantly urged upward. At this time, the number of the push-up springs 15 to be installed is not particularly limited, and can be appropriately increased in the case of a relatively large sheet feeding device. Further, the push-up spring 15 can be replaced with a leaf spring or the like in addition to the coil spring.

A regulating roller 20 is arranged in the substantially central region above the paper 10 along the direction orthogonal to the paper surface. Both ends in the axial direction of the regulation roller 20 are supported by bearings (not shown) so as not to move in the vertical direction, and the uppermost sheet 10 can always be positioned at the same height position. The height position at which the regulation roller 20 is installed is within the vertical movement region of the sheet feeding roller, which will be described later.

A paper feed roller 30 is arranged in the vicinity of the regulation roller 20. The paper feed roller 30 is rotatably provided with its rotation shaft 30A supported by a support arm 31. The support arm 31 is pivotally supported by a fulcrum 33, which allows the paper feed roller 30 to move in the vertical direction. In this embodiment, the paper feed roller 3
0 is configured to be urged toward the sheet 10 via the coil spring 35, but the sheet feeding roller 30 may contact the sheet 10 due to its own weight.

With the above-described structure, the paper feeding device according to the present embodiment always has the push-up plate 1 as shown in FIG.
2 is pushed upward by the urging force of the push-up spring 15, and the uppermost sheet 10 is set at a constant height position by the regulation roller 20.

At this time, the sheet feeding roller 30 is rotated in the direction of the arrow in FIG. 2 when the outer peripheral surface of the sheet feeding roller 30 comes into contact with the sheet 10 by the action of the coil spring 35 and the driving means (not shown) is driven. The upper sheet 10 is sent out and it is possible to feed the sheets one by one through a known separating means.

[0017]

The present invention is constructed as described above, and
According to this, according to this, since the sheet urged by the urging means is held at a constant height position by the regulation roller, the vertically movable sheet feeding roller is always brought into contact with the sheet at a constant pressure. Therefore, stable paper feeding performance can be obtained regardless of the type and thickness of the paper. Moreover, since such an effect can be obtained only by providing the regulation roller, there is no fear of complicating the structure, and it can be provided at low cost, and
It is possible to provide a sheet feeding device that has an unprecedented excellent effect that can be realized in size and weight.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a sheet feeding device according to the present invention, showing a state in which a sheet is not in contact with a sheet feeding roller.

FIG. 2 is a schematic cross-sectional view showing a state at the time of sheet feeding in the above embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Paper 12 Push-up plate 15 Push-up spring as biasing plate urging means 20 Regulation roller 30 Paper feed roller

Claims (2)

[Claims] 1. A push-up plate on which a plurality of sheets are stacked,
A raising plate urging means for urging the pushing up plate toward the paper feed roller is provided, and the uppermost sheet is brought into contact with the paper feed roller by the urging force of the raising plate urging means so that a predetermined sheet can be delivered. In the paper apparatus, a regulating roller is provided in the vicinity of the paper feed roller, the regulation roller being in contact with the uppermost paper sheet to keep the contact pressure between the paper feed roller and the paper sheet constant. Paper equipment. 2. The paper feeding device according to claim 1, wherein the regulation roller is installed at a position corresponding to substantially the center of the push-up plate.