JP3654860B2 - Sheet material supply device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet material supply apparatus provided with a sheet material neutralizing mechanism in a copying machine, a printer, a facsimile, or the like.
[0002]
[Prior art]
In general, an image forming apparatus such as a copying machine, a printer, a facsimile, or the like supplies a sheet material such as a recording sheet or a document set on a sheet feeding cassette, a manual sheet feeding tray, or a document tray to an image forming unit or an image reading unit. A sheet material supplying device (hereinafter referred to as a paper feeding device) is provided.
FIG. 1 is a schematic view showing a cross section of a conventional general paper feeder Z. The conventional paper feeding device Z has a cylindrical paper feeding roller 1 formed on its peripheral surface with a layer made of rubber or the like having a high frictional resistance, and is rotatably supported by a predetermined shaft 3a. A lift plate 3 detachably attached to the roller 1, and a sheet material placed on the lift plate 3 is elastically biased to the paper feed roller 1 by an elastic member such as a coil spring 3 b, When the sheet feeding roller 1 rotates, only the uppermost sheet material in contact with the sheet feeding roller 1 is separated by the friction pad 4 urged by the sheet feeding roller 1 by the coil spring 4b to the image forming unit or the like. Supplied towards. The lift plate 3 is provided on the paper feed roller 1 side of the paper feed tray 2 on which the sheet material is placed.
Here, the lift plate 3 is once separated from the paper feed roller by the action of a cam (not shown) provided on the rotation shaft 1a of the paper feed roller 1 every time one sheet material is supplied (FIG. 1). The position of the sheet material is urged toward the paper feed roller 1 when the sheet material is moved again to the side close to the paper feed roller 1 side (position shown by the solid line in FIG. 1). As a result, when the lift plate 3 is away from the paper feed roller 1, the sheet material is not urged by the paper feed roller 1, so the paper feed roller 1 is idle and does not feed out the sheet material. Only when the lift plate 3 comes close to the paper feed roller 1, the sheet material urged by the paper feed roller 1 is sent out by the rotation of the paper feed roller 1.
Here, the sheet material supplied by the sheet feeding roller 1 is rubbed during sheet feeding to generate static electricity due to frictional charging. When this static electricity accumulates, it becomes difficult for a plurality of sheet materials to be peeled off one by one, and even if separation by the friction pad 4 or the like is used, double feeding in which two or more sheet materials are supplied is likely to occur. Furthermore, such static electricity becomes noise and leads to malfunction of electronic components.
Conventionally, in order to prevent the charging of the sheet material as much as possible, the lift plate 3 is used as a metal plate to release the charge of the sheet material.
[0003]
[Problems to be solved by the invention]
However, even if the lift plate 3 is a metal plate, if the number of sheets supplied increases and the amount of generated static electricity increases, the static electricity accumulates in the lift plate 3 as a result. There was also a problem that led to malfunction of electronic parts.
Accordingly, the present invention has been made in view of the above circumstances, and the object of the present invention is that the sheet material is double-fed or an electronic component malfunctions due to static electricity generated by rubbing the sheet material. An object of the present invention is to provide a sheet material supply device that prevents this.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a rotating sheet feeding roller, a first position where the uppermost surface of one or a plurality of sheet materials placed is in pressure contact with the sheet feeding roller, and the uppermost surface of the sheet material. And a lift plate that reciprocally moves between a second position away from the paper feed roller, and a predetermined conductive member that is grounded via a rotation shaft of the paper feed roller. And a sheet material supply device configured to contact the conductive member each time the lift plate moves to the second position.
For example, the conductive member is made of a metallic member so as to be rotatable on a rotating shaft of the grounded paper feed roller and to come into contact with the lift plate moved to the second position.
Thus, whenever the lift plate is separated from the paper feed roller, it contacts the conductive member and is grounded, so that it is possible to prevent static electricity from accumulating on the lift plate. It is possible to prevent malfunction of electronic components due to feeding and noise.
In addition, since the conductive member is grounded via the rotation shaft of the paper feed roller, existing metal members such as the rotation shaft of the paper feed roller can be used effectively, and a new ground wire for static elimination can be used. There is no need to provide a space, and there is no loss of size and weight.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments and examples of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. It should be noted that the following embodiments and examples are examples embodying the present invention, and do not limit the technical scope of the present invention.
FIG. 1 is a schematic view showing a cross section of the paper feeding device X according to the embodiment of the present invention, and FIG. 2 is a perspective view of a main part of the paper feeding device X according to the embodiment of the present invention.
A sheet feeding device X according to an embodiment of the present invention is an image forming apparatus such as a copying machine, a printer, a facsimile, and the like, such as a recording sheet or a document set on a sheet feeding cassette, a manual sheet feeding tray, or a document tray. It is an example of a sheet material supply device that supplies a sheet material to an image forming unit or an image reading unit.
As shown in FIG. 1, the sheet feeding device X has the same structure and operation as seen from the cross section and is the same as the conventional sheet feeding device Z described above.
Next, the charge eliminating mechanism of the paper feeding device X will be described with reference to FIG.
FIG. 2 is a perspective view showing the configuration of the paper feed roller 1 and the lift plate 3 which are the main parts of the paper feed device X.
As described above, the lift plate 3 made of metal such as iron is rotatably supported by the shaft 3a, and the sheet material s on the lift plate 3 is elastically applied in the direction of the paper feed roller 1 by the coil spring 3b. Be forced. Here, in the lift plate 3, the protrusion 3 c provided on the upper surface of the lift plate 3 contacts the cam 1 b provided on the rotation shaft 1 a of the paper feed roller 1, and the paper feed roller 1 rotates. As a result, the cam 1b reciprocates between a position close to the paper feed roller and a position away from the paper feed roller.
FIG. 2 shows a state when the lift plate 3 comes to the position farthest from the paper feed roller 1 by the action of the cam 1b. In this state, since the sheet material s is not biased by the paper feed roller 1, the paper feed roller 1 runs idle and does not feed out the sheet material.
When the paper feed roller 1 further rotates from the state of FIG. 2, the lift plate 3 moves to the side closest to the paper feed roller 1. At this time, the uppermost surface of the sheet material s is moved to the paper feed roller 1. Energize. As a result, the uppermost sheet material s urged by the paper feed roller 1 is sent out by the rotation of the paper feed roller 1. Hereinafter, the uppermost surface of the sheet material s is the first position where the lift plate 3 is urged by the paper feed roller 1, and the position where the lift plate 3 is farthest from the paper feed roller 1 (shown in FIG. 2). Position) is referred to as a second position.
A metal conductive member 6 such as an iron plate is rotatably provided on the rotating shaft 1a of the paper feed roller 1 (free state) . The conductive member 6 is in contact with the rotary shaft 1a of the feed roller 1, the rotary shaft 1a is in contact with the side wall 5 made of a metal such as iron which is a supporting member, the side wall 5 is grounded. That is, the conductive member 6 is grounded through the rotating shaft 1a and the side wall 5. Further, the conductive member 6 is provided so as to come into contact with the lower surface of the lift plate 3 when the lift plate 3 is moved to the second position (position in FIG. 2).
As a result, the lift plate 3 is in contact with the conductive member 6 and grounded every time the lift plate 3 moves to the second position, so that static electricity can be prevented from accumulating on the lift plate 3.
Further, since the lift plate 3 is moved to the first position where the sheet material s is rubbed and static electricity is generated after the charge is removed (grounded) at the second position, the sheet is always fed from the state where the charge is removed. Is started. Therefore, there is also an effect that the sheet material that is likely to occur at the start of sheet feeding is less likely to occur. In addition, the lift plate 3 is moved to the first position immediately after being neutralized (grounded) at the second position, so that the sheet feeding is started. When the frictional resistance of the sheet is the largest (static friction), the charging state is the lowest, and sheet feeding is less likely to occur than when the charge is removed (grounded) at other times (for example, during paper feeding). .
Furthermore, the lift plate 3 can be grounded via a metal member such as a rotating shaft of an existing paper feed roller and its supporting member only by providing a conductive member 6 which is a metal plate having a very light weight and a small installation capacity. Therefore, there is no need to provide a new grounding wire for static elimination, and there is no loss of size and weight. In particular, in a small machine (printer, copying machine, etc.) in which most of the members are made of resin for size reduction and weight reduction, the rotation shaft 1a of the paper feed roller 1, the support member 5 of the rotation shaft, etc. Since metal is used only for some of the members that require strength, it is particularly effective to use these existing metal members for grounding. Of course, the conductive member 6 may be provided on a directly or indirectly grounded metal portion other than the rotating shaft 1a of the paper feed roller 1, such as the side wall 5 (supporting member of the rotating shaft 1a). .
[0006]
【The invention's effect】
As described above, according to the present invention, each time the lift plate is separated from the paper feed roller, it contacts the conductive member and is grounded, so that it is possible to prevent static electricity from accumulating on the lift plate. It is possible to prevent malfunction of electronic components due to double feeding of sheet material and noise. In addition, since the lift plate is always discharged (grounded) and then starts to be fed close to the feed roller side, the lift plate is the most at the start of feeding, that is, when the frictional resistance between the sheet materials is the highest. The sheet is in a low charge state, and the sheet material is less likely to be double fed than when it is removed (grounded) at other times.
Furthermore, the lift plate can be grounded via a metal member such as the rotating shaft of the existing paper feed roller and its supporting member by adding a very lightweight conductive member with a small installation capacity. There is no need to install a new ground wire, and there is no loss of size and weight. In particular, in small machines (printers, copiers, etc.) where most of the members are made of resin in order to reduce size and weight, the strength of the rotating shaft of the paper feed roller and the support member of the rotating shaft is required. Since metal is used only for some of the members, it is particularly effective to use these existing metal members for grounding.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a cross section of a sheet feeding device X according to an embodiment of the invention.
FIG. 2 is a perspective view of a main part of a paper feeding device X according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Paper feed roller 1a ... Rotary shaft 1b of a paper feed roller ... Cam 2 ... Manual feed tray 3 ... Lift plate 3a ... Shaft 3b, 4b ... Coil spring 3c ... Projection part 4 ... Friction pad 5 ... Side wall (support member)
s ... Sheet material

Claims (2)

A rotating paper feed roller, a first position where the uppermost surface of the one or more sheets placed thereon is in pressure contact with the paper feed roller, and a second position where the uppermost surface of the sheet material is separated from the paper feed roller A sheet supply device comprising a lift plate that reciprocates between
A predetermined conductive member grounded via a rotation shaft of the paper feed roller;
A sheet material supply apparatus configured to contact the conductive member each time the lift plate moves to the second position. 2. The sheet according to claim 1, wherein the conductive member is a metal member that is rotatably provided on a rotating shaft of the grounded paper feed roller and is in contact with the lift plate moved to the second position. Material supply device.

Images