JPH0494339A - Paper feeding device - Google Patents

Abstract

PURPOSE:To prevent the double feeding of sheets of plural kinds by mounting a double feeding prevention member on a front end regulating member of a cassette in such a way that it can be rotated, and by regulating the rotational angle through an angle adjusting means. CONSTITUTION:A double feeding prevention member 11 is mounted on a front end regulating member 7 of a cassette 1 in such a way that the member can be rotated around a shaft 13, while elastic power is given to the double feeding prevention member 11 by a spring 12. A sheet 10 is fed out by the rotation of a feeding roller 6, and is abutted on a frictional material 14 mounted on the upper surface of the double feeding prevention member 11, while the double feeding prevention member 11 is rotated around the shaft 13. An angle regulating member 15 is mounted on the regulating member 7 in such a way that the member can be moved vertically, while the prevention member 11 is rotated by a protruded part 15a of the angle regulating member, and the rotation is stopped thereby. A thin sheet which is easily double-fed, or a sheet curled upward are to be fed, the rotational angle of the double feeding prevention member 11 is widened by moving the regulating member 15 upward, and the resistance between the sheet 10 and the frictional material 14 is increased. When a thick sheet is to be fed, the rotational angle is reduced, and double feeding can thus be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sheet feeding device used in image forming apparatuses such as copying machines and laser printers.

Conventional technology Conventionally, the double feed prevention member of a paper feed device used in a copying machine, etc. has been either the self, an elastic body such as a plate spring, something supported by an elastic body, or a structure formed in a cassette. Become,
All of them were simply fixed to the double feed prevention member or to the paper feed side of the cassette.

A conventional paper feeding device will be described below.

FIG. 3 is a perspective view of a conventional paper feeding device, and FIG. 4 is an enlarged view of main parts of the paper feeding section. 1 is a cassette that stores sheets, 2 and 3 are side plates that regulate the sheet width, 4 is a sheet placement plate that pushes up the sheet, 5 is an elastic member that pushes up the sheet placement plate, and 6 is a paper feeder that sends out the sheet. roller,
Reference numeral 7 denotes a leading edge regulating member that regulates the position of the leading edge of the sheets; 8 denotes a double-feed prevention member that feeds the sheets one by one; 9 is attached to the double-feed prevention member 8, and assists separation between sheets by frictional resistance with the sheets. Friction material. 10 is a sheet made of paper, resin film, or the like.

The operation of the conventional paper feeding device configured as described above will be described below.

The sheet 10 is stored in the cassette 1 in contact with the side plates 2 and 3, the leading end regulating member 7, etc., and is sent out by the paper feed roller 6. At this time, the plurality of sheets 10 come into contact with the double-feed prevention member 8, and due to the elasticity of the double-feed prevention member 8 and the resistance of the friction material 9, the uppermost sheet in contact with the paper feed roller 6 l
Only O is sent into the image forming apparatus from the cassette.

Problem to be Solved by the Invention However, in the above conventional configuration, the double feeding prevention member 8,
Since it is fixed to one end of the tip regulating member 7 of the cassette L, the inclination angle of the electric feed prevention member is fixed, and the elastic force of the double feed prevention member is also constant, so the thickness of the sheet and the stiffness of the sheet are fixed.
It was not possible to deal with curls, etc., and problems such as double feeding and jamming occurred. Furthermore, in order to avoid these problems, it has been necessary to severely limit the type and material of the sheet.

Means for Solving the Problems The present invention is such that a double-feed prevention member is rotatably attached to a tip regulating member, and an angle adjustment means for regulating the rotation angle of the double-feed prevention member is provided.

Effect With the above configuration, in the case of a thin sheet or a sheet that curls upward and is easily double-fed, the angle regulating means is moved upward and the rotation angle of the double-feed prevention member is reduced, thereby preventing the sheet and the double-feed prevention member from collapsing. This increases the resistance with the friction material and prevents double feeding.

On the other hand, in the case of a thick sheet or a sheet that curls downward and is likely to jam, move the angle regulating means downward,
By increasing the rotation angle of the double-feed prevention member, the resistance between the sheet and the friction material of the double-feed prevention member is reduced, and jams are prevented.

Embodiment FIG. 1 is an enlarged view of the main parts of a paper feeding device in an embodiment of the present invention, and FIG. 2 is a diagram showing the operating state during paper feeding. 1 is a cassette, 2 is a side plate, 4 is a sheet mounting plate, 5 is an elastic material, 6
1 is a paper feeding roller, 7 is a leading end regulating member, and 10 is a sheet, which are the same as those in the conventional example, and therefore are given the same numbers and their explanation will be omitted.

Reference numeral 11 denotes a double-feed prevention member for preventing double-feeding of sheets; 12 is an elastic material such as a spring or rubber that provides elastic force to the double-feed prevention member 11; 13 is a rotating shaft of the double-feed prevention member 11; and 14 is a heavy A friction material 15 is attached to the double feeding prevention member 11 and helps prevent double feeding by frictional resistance with the sheet.
This is an angle regulating member constituting an angle regulating means that adjustably regulates the rotation angle of the distal end regulating member 7, and is provided so as to be vertically movable through a sliding groove or the like of the tip regulating member 7.

Regarding the paper feeding device of this embodiment configured as above,
The operation will be explained below.

When the sheet IO is fed out by the rotation of the paper feed roller 6, it comes into contact with the friction material 14 attached to the upper surface of the double-feed prevention member 11. At that time, the double feeding prevention member 11 moves the convex portion 1 of the angle regulating member 15 around the rotation shaft 13 by the conveyance force of the sheet 10 given by the paper feed roller 6.
Rotate until it comes into contact with 5a. At that time, the sheet 10 is rotated around the rotating shaft 13, and an elastic member 12 is attached so as to return the double-feed prevention member 11 in the direction opposite to the traveling direction of the sheet 10.
Due to the elastic force of the uppermost sheet lOa and the frictional resistance of the friction material 14, only the uppermost sheet lOa is fed into the image forming apparatus from the cassette 1, and when the sheet lOa leaves the double feed prevention member 11, the electric transmission prevention member 11 will return it to its initial position.

The rotation angle of the double feed prevention member +1 is set to be small when it is located above the angle regulating member 15, and to be large when it is located below.

In the case of thin sheets that are easily double-fed or sheets that curl upward, the angle regulating member 15 is moved upward and the rotation angle of the double-feed prevention member 11 is reduced to reduce the sheet lO.
and the friction material 14 of the double feed prevention member 11,
Prevent double feeding.

On the other hand, in the case of thick sheets that tend to jam, or sheets that curl downwards, by moving the angle regulating member 15 downward and increasing the rotation angle of the double-feed prevention member 11, double-feeding with the sheet 10 can be avoided. The resistance between the prevention member 11 and the friction material 14 is reduced to prevent jamming. Incidentally, the angle regulating member 15 may be slidably provided on the columnar portion 11a of the double feeding prevention member 11 to prevent double feeding. At this time, the convex portion 15a of the angle regulating member 15 may be provided so as to come into contact with the tip regulating member 7. It is convenient to use different cassettes depending on their size.

Effects of the Invention The present invention makes it possible to rotate plain paper, OHP sheets, and envelopes by making the double-feed prevention member, which is provided for the purpose of preventing double-feeding of sheets, rotatable and adjustable to a predetermined rotation angle. ,
Accurately responds to changes in the condition of sheets such as postcards due to the type of sheet, curling up and down, strength of the back, etc., prevents double feeding and jams of sheets, and handles paper types with a single paper feeder. It is designed to be compatible with a wide range of environments.

[Brief explanation of the drawing]

Fig. 1 is an enlarged view of the main parts of a paper feeding device according to an embodiment of the present invention, Fig. 2 is a diagram of the operating state during paper feeding, Fig. 3 is a perspective view of a conventional paper feeding device, and Fig. 4 is the same. FIG. 2 is an enlarged view of a main part of a double feeding prevention section of the paper feeding device. ...Sheet placement plate...Paper feed roller double feeding prevention member 0...Sheet 2...Elastic material 4...Friction material

Claims (1)

[Scope of Claims] A side plate that regulates the width of the sheet, a leading edge regulating member that regulates the position of the leading edge of the sheet, and a sheet mounting plate that pushes the sheet toward the paper feed roller located above via an elastic member. The paper feeding device includes: a double-feed prevention member rotatably disposed on the leading edge regulating member; an elastic member that biases the double-feed prevention member; and a rotation angle of the double-feed prevention member. A paper feeding device comprising: an angle adjusting means for controlling the angle;