JP2003118848A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder for an electrophotographic unit, capable of pressing down paper ends without causing scars or bends on the paper ends during paper charging and without being affected by variation in the printing position, and thereby capable of preventing disturbance in the attitude of paper being transported. SOLUTION: In this paper feeder for the electrophotographic unit provided with paper end pressing members on its inner walls for pressing paper ends at the printing position for stabilizing attitude of the paper, the members are drawn back to a position causing no damage on the paper ends by a withdrawing means when papers are put in or out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device of a printing device.

[0002]

2. Description of the Related Art FIG. 6 is a cross-sectional view showing a structure of a conventional sheet feeding device, that is, a device generally called a hopper, and a state in which sheets (cut sheets) are stacked on the hopper and printing is performed. is there. In FIG. 6, 1 is a hopper, and 2 is a main body of a printing apparatus using an electrophotographic method.

A table 4 for stacking sheets 3 is provided inside the hopper 1. The table 4 has a height that allows printing when the hopper 1 is stored in the main body 2 of the printing apparatus. Is connected to a device for raising. The contact sensor 5 is a detection device that detects the height of the paper 3, and the paper 3 is controlled by the contact sensor 5 so that it is always held at a printable position. The paper 3 held at the printable position is conveyed by a paper feed roller 6 at regular intervals to a paper conveyance mechanism (not shown) installed in the main body 2, and printing is performed by a printing mechanism (not shown).
Will be printed.

However, the paper used in the electrophotographic printer is generally susceptible to the storage environment such as temperature and humidity, and the paper left in a high humidity environment for a long time has a curved shape. Or it may change into a wavy shape.

When such a sheet is loaded in the hopper 1 and printing is performed, the sheet 3 is conveyed when the sheet is conveyed by the sheet feeding roller 6.
In some cases, a resistance force other than the advancing direction acts on the sheet 3 and the posture of the sheet 3 is disturbed. As shown in FIG. 7, there is a problem that the sheet is obliquely fed out of the regulation of the inner wall 7 of the hopper 1 and the paper guide 8. .

[0006] Further, the conveyance attitude of the paper 3 is determined by the paper feed roller 6
Also, when the paper feed roller 6 is installed in one of the left and right sides, the paper feed roller 6 is attached to the paper 3 as compared with the case where the paper feed roller 6 is arranged in the central portion of the paper 3. Since the rotational moment around the center acts, the conveyance posture is disturbed, and there is a tendency that the frequency of skew feed increases.

In order to prevent the above-mentioned problem, in the prior art, as shown in FIG. 8, there is a method in which a brush-like member 9 is attached to the inner wall 7 of the hopper 1 at the sheet printing position to forcibly hold the edge of the sheet. It was

Further, as shown in FIG. 9, there is also a method in which a claw-shaped member 10 is installed on the inner wall of a hopper to forcibly hold the edge of the paper to prevent the conveyance posture of the paper 3 from being disturbed.

[0009]

In the above-mentioned conventional paper feeding device in which the brush-like member is provided on the inner wall of the hopper, the amount of printing is large, and the brush-like member is worn out quickly in the electrophotographic apparatus in which the paper is loaded many times in the hopper. Therefore, it becomes necessary to replace it regularly, and maintenance is not efficient, and there is a problem in terms of maintenance cost.

That is, the method for installing the brush-like member is as follows.
Although it is advantageous for a personal computer electrophotographic device having a relatively small print amount, it is not suitable for a high-speed electrophotographic device having a large print amount. Further, in the above-described paper feeding device in which the claw-shaped member is provided on the inner wall of the hopper, the paper may be damaged when the paper is loaded. Further, since the claw-shaped member is fixed to the inner wall of the hopper, it is not possible to cope with variations in the printing position due to changes in the shape of the paper, that is, variations in the paper feeding position and mechanical variations in the printing position of the hopper itself. In some cases, a phenomenon such as not being able to press a part sufficiently or being pressing too much is necessary, and it may not be possible to obtain a sufficient effect of preventing the disturbance of the conveyance posture of the paper.

The object of the present invention is to solve the above problems and to prevent damage to the paper when loading the paper into the hopper.
In addition, in order to cope with variations in the printing position, the edge of the sheet is always held at a constant pressure, and even in an electrophotographic apparatus with a large printing amount, it is possible to prevent disturbance of the sheet conveyance attitude during sheet feeding, which is advantageous in terms of maintenance cost. It is an object of the present invention to provide a sheet feeding device equipped with a sheet edge pressing means for the purpose.

[0012]

SUMMARY OF THE INVENTION The above-mentioned object is to contact the edge of the paper at a constant pressure at the printing position and to move in the same direction as the moving direction of the paper stacking member, that is, the table. This is achieved by installing a sheet edge pressing means that retracts to a position where the paper is not applied to the inner wall of the hopper.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the sheet feeding device configured as described above, since the sheet edge pressing member retracts when the sheet is loaded,
Without damaging the edge of the paper such as scratches and creases, and when the table is loaded and the table moves to the print position, the position of the paper edge retainer changes according to the variation of the print position. Therefore, it is possible to always press the edge of the paper with a constant pressure.

Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.

In FIG. 1, 1 is a hopper, and the hopper 1
A table 4 for loading sheets 3 is installed in the interior of the machine, and when the hopper 1 is moved to and housed in the main body 2 of the electrophotographic apparatus, it is lifted by a drive device that raises the sheets 3 to a printing position. ing. The amount of rise of the sheet 3 is detected by detecting the upper surface of the sheet by the contact type sensor 5, and the sheet 3 stacked on the table 4 is controlled so as to always maintain a constant height.

In this structure, the inner wall of the hopper 1 is
At the printing position of the paper 3, that is, at the position where the paper feed roller 6 conveys the paper 3, a pressing means 16 for pressing the edge of the paper from above is installed.

The structure of the pressing means 16 is shown in FIGS. The pressing means 16 is composed of a conical resin member 11 that is a paper edge pressing means and a leaf spring member 12 that is a retracting means that supports the resin member 11.
Is configured so as to come into contact with the edge of the sheet through an elongated hole 13 provided in the inner wall of the hopper 1. Further, the leaf spring member 12 is attached to the shaft 15 through the elongated hole 14, and an appropriate gap is provided between the attaching portion and the leaf spring member 12,
After the paper is loaded on the table 4, it is slidable in the direction of moving to the printing position, that is, in the vertical direction by the length of the slot 14 and the amount of clearance of the shaft. When a horizontal force is applied to the resin member 11, the leaf spring member 12 bends and the resin member 11 can move in the horizontal direction.

When printing is performed by the paper feeding device of the electrophotographic apparatus having the above-described structure, first, when the paper 3 is loaded into the hopper 1, the paper 3 loaded as shown in FIG.
Since the paper comes in while pushing the slope of the resin member 11 in the horizontal direction, it is possible to prevent the problem that the edge of the paper is damaged.
Further, since the resin member 11 has a conical shape, it can be moved horizontally not only in the vertical direction but also when the paper 3 is loaded from the horizontal direction. Further, even if the sheet 3 once loaded is removed, or if something other than the sheet 3 comes into contact with, for example, the hand of the operator, the same operation is performed. Therefore, the resin member 11 and the leaf spring member 12 as a whole, that is, It is possible to prevent the parts of the holding means 16 from being damaged.

Next, when the sheets 3 are stacked on the table 4 and the table elevating mechanism raises the sheets 3, as shown in FIG. 5, the end portions of the sheets are placed on the resin member 11 at the printing position, that is, before the sheet feeding position. Starting contact, resin member 11 and leaf spring member 1
2 is stopped at the printing position while being lifted to the edge of the sheet. In this state, the edge of the sheet is pressed downward by the weight of the resin member 11 and the leaf spring member 12, and the effect of preventing the conveyance posture of the sheet 3 from being disturbed can be obtained. Further, since the resin member 11 is on the edge of the sheet, it is possible to follow variations in the height of the printing position and variations in the height of the printing position due to a change in the shape of the sheet 3, and the edge of the sheet is always kept at a constant pressure. It is possible to hold down. The weight of the resin member 11 and the leaf spring member 12, the angle of the conical slope of the resin member 11, and the bending force of the leaf spring member 12 need to be set appropriately according to the characteristics of the printing paper. 11 and the leaf spring member 12 are too heavy,
On the contrary, it may cause the paper conveyance posture to be disturbed.

In this embodiment, the weight of the paper is 55 to 13
When using 5 kg of paper, the total weight of the resin member 11 and the leaf spring member 12 is 10 (g), the angle θ of the conical slope of the resin member 11 is 100 degrees, and the spring constant of the leaf spring member 12 is 0.
Good results were obtained by setting 181 (kg / mm).

[0021]

As described above, according to the present invention, a constant pressure is always applied without damaging the edge of the paper when the paper is loaded, such as scratches or folds, and without being affected by the variation in the printing position at the printing position. It is possible to prevent the disturbance of the conveyance posture of the paper by pressing the edge of the paper. Further, since the brush member which is worn away quickly unlike the prior art is not used for the sheet edge pressing means, the maintenance cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a sheet feeding device that is an embodiment of the present invention.

FIG. 2 is a schematic view showing the mounting of the sheet edge pressing means and the retracting means, which is an embodiment of the present invention.

FIG. 3 is a schematic view showing a sheet edge pressing means and a retracting means which is an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a sheet edge pressing unit and a retracting unit when a sheet is loaded in a hopper which is an embodiment of the present invention.

FIG. 5 is a schematic view showing a state in which paper is loaded into a hopper which is an embodiment of the present invention, the table is raised, and the paper edge pressing means comes into contact with the paper edge.

FIG. 6 is a schematic view showing a conventional paper feeding device.

FIG. 7 is a schematic view showing how a sheet is obliquely fed in a conventional sheet feeding device.

FIG. 8 is a schematic view of a conventional paper feeding device.

FIG. 9 is a schematic view of a conventional paper feeding device.

[Explanation of symbols]

1 ... Hopper, 2 ... Electrophotographic apparatus main body, 3 ... Paper, 4 ...
Table, 5 ... Contact type sensor, 6 ... Paper feed roller, 7 ... Hopper inner wall, 8 ... Paper guide, 9 ... Brush-like member, 10
... Claw-shaped member, 11 ... Resin member, 12 ... Leaf spring member, 13
... elongated hole, 14 ... elongated hole, 15 ... shaft, 16 ... holding means.

Claims (2)

[Claims] 1. A feeding device for an electrophotographic apparatus, comprising: a storage member for storing a plurality of sheets of paper; a table portion for stacking the sheets; and a moving device for moving the table portion to a printable position of the sheets. In the paper apparatus, a paper edge pressing unit that presses an edge of the paper in the paper stacking direction and a retracting unit that retracts the paper edge pressing unit from the paper pressing position when the paper is loaded are provided inside the storage unit. Paper feeding device. 2. The sheet feeding device according to claim 1, further comprising: a sheet edge pressing unit made of at least a resin member and a retracting unit made of at least a leaf spring member.