JPH069073A - Paper feed device - Google Patents

Abstract

PURPOSE:To simply adjust a mechanism by which paper sheets loaded on a paper feed table are delivered in order in the paper feed direction, and minify dislocation of the paper feed table. CONSTITUTION:In the paper feed device provided with a hopper 3 in which paper sheets 5 are loaded on a paper feed table 4 and the height of the uppermost paper sheet is controlled to be in a decided level, and a pick unit 6 by which the paper sheets 5 are delivered while contacting at least one pick roller 61 with the uppermost sheet of the paper sheets 5 by required pressing force through elastic members 64a, 64b, the device is constituted so that a one point supporting metal fitting 7 is provided between the frame 12 of the device and the pick unit 6 so as to be on a vertical plane containing the delivery direction line of the center part of the pick roller 61, and it is oscillated only in the direction of balancing the pressing force of the pick roller 61 against the uppermost sheet of the paper sheets 5.

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 used in an electrophotographic apparatus or the like, and more particularly to a mechanism for sequentially feeding sheets stacked on a sheet feeding table in a sheet feeding direction.

In recent years, as the printing speed of an electrophotographic apparatus has become faster, it has been required to increase the capacity of a paper feed table (paper hopper) for supplying paper to the electrophotographic apparatus. However, the capacity of, for example, a cassette type paper feed table attached to this electrophotographic apparatus is limited by the size of the electrophotographic apparatus. Therefore, in order to realize a large capacity, a separate type paper feeding device is generally added to the electrophotographic apparatus, but the reliability of the paper feeding mechanism of the paper feeding device is improved with the increase in size. It has been demanded.

[0003]

2. Description of the Related Art FIGS. 3A and 3B are structural views of a conventional sheet feeding device, in which FIG. 3A is a side sectional view and FIG. In addition, in order to make the description of the configuration and operation easy to understand, the same reference numerals are given to the same portions throughout the drawings, and the duplicated description thereof will be omitted.

In both figures, reference numeral 1 is a sheet feeding device, the main components of which are a carriage 2 for transportation, a hopper 3 which is movable on the carriage 2 in the front-rear direction of the drawing via a slide rail 21, and accommodated in the hopper 3. Paper feed table 4 that is controlled so that it can be moved up and down
And a pick unit 6 having a function of sequentially feeding in the arrow Y direction from the uppermost sheet of sheets 5 such as cut sheets stacked on the sheet feeding table 4.

The raising / lowering mechanism of the sheet feeding table 4 has a function of controlling the uppermost sheet surface position of the sheet 5 to a constant level at all times, and is mounted in the hopper 3 but not directly related to the present invention. Is omitted.

The pick unit 6 is a unit pivotally supported about the center of rotation R. The pick unit 6 picks up the paper 5 while contacting the uppermost paper surface of the paper 5 with a predetermined pressing force, and the picked-up paper 5 in the arrow direction. Registration roller that conveys in the Y direction
62, a conveyance motor 63 for rotating these by a transmission mechanism such as a belt drive, and a spring 64 arranged to press the pick roller 61 against the sheet 5.

In this spring 64, a left spring 64a and a right spring 64b are arranged in a direction in which the bottom surface of the pick unit 6 is attracted to the apparatus frame 12. The pick roller 61 will be described with reference to an example including a left pick roller 61a and a right pick roller 61b.

In order to accurately feed the sheet 5 without misalignment, the rotation axis of the pick roller 61 contacting the uppermost surface of the sheet 5 is maintained in a predetermined direction, and the sheet 5 and the left and right pick rollers 61a, 61b are separated from each other. It is an important condition that a uniform pressing force is applied to the contact surface of. That is, the paper feed table 4
It is necessary to maintain the parallel positional relationship between the pick unit 6 and the pick unit 6. A conventional mechanism for performing this parallel adjustment will be described below.

FIG. 4 is an enlarged view of a main part of a conventional pick unit positioning mechanism. FIG. 4A is a front side exploded perspective view of the pick unit positioning fitting 11 shown in FIG. 3, and FIG. 11 is an exploded perspective view of the back side viewed from the back side.

In both figures, the pick unit positioning metal fitting 11 is a frame 11a formed by bending plates at both ends welded along the apparatus frame 12 (for example, the ceiling surface) of the sheet feeding apparatus 1 shown in FIG. Adjustable by penetrating through the front side of one of the bent plates, the support shaft 11b for the pick unit that is screwed and fixed, and through the elliptical hole 11c formed in the other bent plate on the far end side. It consists of a spindle 11d for a pick unit that is screwed.

By assembling the bearings 65 and 66 provided on the side plates of the pick unit 6 so as to be loosely fitted to the opposing support shafts 11b and 11d, the pick unit 6 is centered on the support shafts 11b and 11d. It can swing freely. By adjusting the fixing position of the support shaft 11d for the pick unit with respect to the oval hole 11c, the parallelism of the contact position of the pair of pick rollers 61 shown in FIG. 3 with respect to the sheet 5 can be arbitrarily adjusted. .

FIG. 5 is an explanatory view of a main part of a conventional inclination correcting mechanism of a hopper. In the figure, reference numeral 22 is a block for mounting the slide rail 21 which is screwed on the upper surface of the carriage 2, and the hopper 3 is mounted via the slide rail 21 so as to be movable in the direction perpendicular to the paper surface of this figure. . The slide rail 21 is used when replenishing the paper in the hopper 3.

Reference numeral 23 is a screw for fixing the block 22, and 24 is a screw.
Is a spacer to be inserted into one end of the block 22 in the longitudinal direction with respect to the upper surface of the trolley 2. By selectively adjusting the thickness of the spacer 24, the inclination of the hopper 3, that is, FIG.
It is possible to adjust the parallelism of the contact position of the pick roller 61 with respect to the sheet 5 shown in FIG. Further, it is also possible to make a correction by using a push screw without using the spacer 24.

By using one or both of the two types of adjusting mechanisms described above, the paper feeding table 4 can be assembled at the time of assembling the apparatus.
And the parallel positional relationship between the pick unit 6 and the pick unit 6 were adjusted.

[0015]

A conventional paper feed table 4
According to the adjusting means for the parallel positional relationship between the pick unit 6 and the pick unit 6, it takes a long time to perform the adjustment. Also,
If the position of the paper feed table or the like shifts during operation of the apparatus, there is a drawback that causes a failure such as skew.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a sheet feeding device which is easy to adjust and has a small displacement of the sheet feeding table.

[0017]

To achieve the above object, as shown in FIG. 1, a hopper 3 for stacking sheets 5 on a sheet feeding table 4 and controlling the height of the uppermost sheet surface to a constant level.
And a pick unit 6 for feeding out the paper 5 while bringing at least one pick roller 61 into contact with the uppermost paper surface of the paper 5 by an elastic member 64 with a required pressing force. A one-point support metal fitting 7 is provided between the device frame 12 and the pick unit 6 on a vertical plane including the payout direction line at the center of the pick roller 61, and the pick roller 61 with respect to the uppermost paper surface of the paper 5. It is configured to swing only in the direction in which the pressing force is balanced.

[0018]

The pick unit 6 supported by the one-point support metal fitting 7 provided on the vertical plane including the payout direction line at the center of the pick roller 61 can swing about the shaft 72 in the arrow A direction.

At this time, when the shaft 72 is at the center of gravity with respect to the swinging direction of the pick unit 6, the uppermost sheet surface of the sheet 5 moves up from the non-contact state to the pick roller 61 and approaches first. One pick roller 61, for example the left pick roller 61
Until it abuts against a, rises further while abutting it, and abuts against the right pick roller 61b, the pick unit 6 swings to follow the uppermost sheet surface with almost no pressing force.

When both pick rollers 61a and 61b come into contact with each other, the pressing forces of the springs 64a and 64b provided on the left and right act equally and press the uppermost sheet surface. Also, if the center of gravity is displaced with respect to the swing direction,
By adjusting the left and right springs 64a and 64b, it is possible to compensate so that a uniform pressing force acts on the uppermost sheet.

[0021]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows the principle of the pick unit positioning mechanism of the present invention. This drawing is different from FIG. 3B in that a single point support fitting 7 is attached instead of the pick unit positioning fitting 11.

In the figure, C is a center line indicating the edge of the vertical plane including the payout direction line at the center of the pick roller 61. The one-point support fitting 7 is a bearing fitting 71 provided on the ceiling of the pick unit 6 on the center line C thereof, and is loosely fitted to the bearing fitting 71, along a vertical plane including the center line C and parallel to the uppermost paper surface. The shaft 72 is provided in the direction in which the shaft 72 and the fixing bracket 73 that fixes the shaft 72 to the device frame 12.

With this one-point support mechanism, the entire pick unit 6 swings only in the direction of arrow A. Then, when the sheets 5 set on the sheet feeding table 4 are gradually raised by driving the hopper 3 when the sheets are set, and the uppermost sheet surface comes into contact with one of the pick rollers 61, for example, the left pick roller 61a, the swinging mechanism The left pick roller by action
61a is lifted around the shaft 72 and then comes into contact with the other right pick roller 61b.

Until the pick rollers 61a and 61b come into contact with the uppermost paper surface, the pick unit 6 swings to follow the uppermost paper surface with little pressing force.
When the paper feed table 4 is further raised, the shaft of the single-point support fitting 7
When gravity is balanced in the swinging direction of the pick unit 6 around 72, the pressing forces of the left spring 64a and the right spring 64b, which have the same pressing force, act equally to reach the required pressing force. At that time, the raising control of the paper feed table 4 is stopped.

If the gravity of the pick unit 6 in the swinging direction is not balanced about the shaft 72 of the one-point support member 7, the balance can be achieved by adjusting the pressing force of the left spring 64a and the right spring 64b. It can be corrected to the position.

FIG. 2 shows a front view of the essential parts of one embodiment of the present invention. The difference between this figure and FIG. 1 is that the swing center point for single point support is brought close to the axis of the pick roller 61, and the swing direction of the pick roller is as vertical as possible.

In the figure, a single-point support fitting 7 is a bearing fitting 74 fixed to the ceiling frame of the pick unit 6 in a suspending direction, and is loosely fitted in the bearing fitting 74, along a vertical plane including the center line C and It is composed of a shaft 75 provided in the paper feeding direction parallel to the uppermost paper surface, and a fixing metal fitting 76 for fixing the shaft 75 to the apparatus frame 12.

The fixing metal fitting 76 supports the shaft 75 in the orthogonal direction, and penetrates both ends of the shaft parallel to the axial center line of the pick roller 61 through stupid holes (not shown) provided on both side surfaces of the pick unit 6 to form an apparatus frame. The mechanism is fixed to 12.
With this configuration, the height of the pick unit 6 can be made small.

According to the above construction, the pick unit 6 as a whole is supported at one point, and the paper 5 of the pick roller 61 faces the vertical plane including the feeding direction line at the center of the pick roller 61.
Since it swings only in the direction to balance the pressing force with respect to the uppermost sheet surface of the pick roller, even if the sheet feeding table 4 is misaligned or an abnormal tilt occurs, the pick roller is automatically moved.
The pressing force on the topmost sheet of 61 is corrected evenly.

[0030]

As is apparent from the above description, according to the present invention, the adjustment time of the parallel positional relationship between the sheet feeding table 4 and the pick unit 6 is shortened, and the sheet feeding table and the like are operated when the apparatus is in operation. There is an effect that it is possible to prevent the occurrence of a fault such as a skew even with respect to the positional deviation.

[Brief description of drawings]

FIG. 1 is a principle diagram of a pick unit positioning mechanism of the present invention.

FIG. 2 is a front view of a main part of an embodiment of the present invention.

FIG. 3 is a structural diagram of a conventional paper feeding device

FIG. 4 is an enlarged view of a main part of a conventional pick unit positioning mechanism.

FIG. 5 is an explanatory view of a main part of a conventional tilt correction mechanism for a hopper.

[Explanation of symbols]

 3 Hopper 4 Paper feed table 5 Paper 6 Pick unit 7 One-point support bracket 12 Device frame 61 Pick roller 64 Elastic member (spring)

Claims (1)

[Claims] 1. A hopper (3) for stacking sheets (5) on a sheet feeding table (4) and controlling the height of the uppermost sheet surface to a constant level,
The uppermost paper surface of the paper 5 is provided with a pick unit (6) for feeding out the paper (5) while at least one pick roller (61) is brought into contact with the elastic member (64) with a required pressing force. In the device, the device frame (12) of the device and the pick unit (6)
A single-point support metal fitting (7) is provided between the pick roller (61) and the top surface of the paper (5) of the pick roller (61) on the vertical plane including the feeding direction line. A sheet feeding device, which is configured to swing only in a direction in which the pressing force is balanced.