JPH06263266A - Paper feed cassette fitting method - Google Patents

Abstract

PURPOSE:To prevent malfunction of a control board or a host system following static electricity due paper friction when a feeder cassette is fitted into a printing machine. CONSTITUTION:Papers 4 are set in a feeder cassette 1 which is fitted to a printing machine 10. The papers 4 are pushed against a pickup roller 11 on the machine 10 side by a paper cassette base 2. The cassette base 2 is electrically connected to the machine mainframe 14 via a metal spring 3, a conductive member 17, an electric resistor 16 and a plate spring 13, and when a feeder cassette 1 is inserted therein discharge gradually occurs through the electric resistor 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing machine such as a copying machine or a printer. In particular, the present invention relates to an optimum method for an apparatus in which static electricity is generated by friction, which is performed by pulling out paper from a paper feed cassette during printing.

[0002]

2. Description of the Related Art In a paper feed cassette, a metal plate is often used as a member for pushing up the paper or for moving the paper to the correct position. When the paper is fed, the paper is pulled out from the paper feed cassette, so that the papers rub against each other to generate static electricity.
This static electricity is accumulated, and when it exceeds a certain limit, it becomes a spark discharge and is radiated to the printer body. This may cause a sudden change in the potential of the main body frame at the ground level to generate noise, which may cause a malfunction in the host board that controls the main body and the previous host system via the I / F. In order to prevent this, the technique of contacting the metal plate with the frame of the main body to discharge static electricity has been used.
As a specific example, a technique in which a metal spring is provided on the main body frame to contact the metal plate in the paper feed cassette, or a chain is hung on the metal plate in the paper feed cassette to contact the main body frame Was widely practiced.

In such a system, static electricity during printing is surely discharged to the main body frame. However, in the case of inserting / removing the paper feed cassette, at the moment when the internal metal plate comes into contact with the main body frame, the paper feed cassette is still used. The static electricity accumulated in the battery will be discharged to the body frame and cause malfunction.

A known example of a paper feed cassette is Japanese Patent Laid-Open No. 61-
Although there are 106341 and Japanese Patent Laid-Open No. 49-18336, they are not related to static electricity.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention intends to prevent the occurrence of malfunction by discharging static electricity gradually even when a paper feed cassette is inserted and removed.

[0006]

In order to solve the above problems, static electricity is prevented from being discharged and accumulated in a paper feed cassette during printing, and static electricity is gradually discharged when the paper feed cassette is inserted and removed. It may be configured as follows. Specifically, the problem can be solved by connecting the metal plate in the paper feed cassette and the main body frame with a member having an electrical resistance value.

[0007]

During printing, static electricity is generated due to friction between the pulled-out paper and the remaining paper, and this static electricity is not accumulated in the paper feed cassette and is scattered to the metal part in the paper feed cassette where static electricity is most likely to be transferred. Since this metal is connected to the frame ground of the main body, it is discharged through the electric resistance as it is and loses the electric charge. On the other hand, when the paper feed cassette is pulled out and reinserted into the main body, static electricity is accumulated due to the friction between the papers or the friction between the paper and the paper feed cassette. Then, when they are fitted together, the accumulated charge flows through the electric resistance to the main body frame, so that the potential change of the frame ground is small, that is, the noise is small.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention and shows a state in which a paper feed cassette 1 is fitted in a printer main body 10 such as a printer or a copying machine.

The paper 4 is stored in the paper feed cassette 1 made of an electrically insulating material. Further, a cassette base 2 made of a metal plate is vertically attached to the paper feed cassette 1, and the paper 4 is lifted upward by a metal spring 3.

On the other hand, on the body side, a pickup roller 11 which is rotatably mounted inside and a paper separating plate 12 which is pressed against the pickup roller 11 are mounted. Pickup roller 1
1 is made of a material such as rubber having a large frictional force for the purpose of rotating and pulling out the paper. Also, the paper separating plate 1
Reference numeral 2 is for pressing the pickup roller 11 from the lower side so that the paper is not double-fed, that is, only the uppermost paper that is in contact with the pickup roller 11 is sent out one by one.

A leaf spring 13 made of a metallic material is fixed to the body frame 14 with screws 15.

A printing mechanism (not shown) such as an electrophotographic printing system or a thermal transfer printing inkjet system is formed inside the main body. Also provided therein is a control board that controls the drive of the individual components of the printing mechanism. The control board is typically electrically connected to the body frame 14 to stabilize its ground level.
Furthermore, in order to control this printing machine from the outside, a host system or controller is often connected via an I / F.

With such a structure, when the pickup roller 11 rotates, the paper 4 is pulled out by the frictional force and sent to the inside of the main body 10. Then, it is printed by the above-mentioned printing mechanism and discharged to the outside of the main body 10.

When printing is continued here, static electricity is generated due to friction between paper sheets, and the electric charges are accumulated and discharged toward the body frame 14 at once. Due to this discharge, the ground level of the main body frame 14 is momentarily raised and becomes noise, which changes the ground level of the control board and causes a malfunction. In addition, the host system may malfunction through the I / F.

In order to prevent such noise,
A conductive member around the paper 4 may be connected to the main body frame 14 to discharge the electric charge generated by friction without being accumulated. To this end, the member 5 is used as a conductive material, and the conductive member cassette base 2 which is usually a metal plate in the paper feed cassette 1 is connected to the main body frame 14 through the metal spring 3 and the main body side leaf spring 13. Good.

However, there is a problem with this configuration as well. When the paper is exhausted and the paper is replenished, the paper feed cassette 1 is inserted and removed. At this time, the paper is rubbed and charged. When the sheet cassette 1 is inserted into the main body 10, this electric charge is discharged to the main body frame 14 at once through the above-mentioned path. Therefore, the same problem as described above occurs.

In order to solve this problem, the present invention is to change the member 5 into a semiconductive member having a certain resistance value.

By doing so, during printing, the charge generated by friction is also discharged through the same path, so that the charge is not accumulated. Further, even when the paper feed cassette 1 is inserted, the accumulated charge is discharged through the semiconductive member 5, and the resistance value of the member 5 restricts the flow of the charge, so that the charge is gradually discharged. Body frame 1
The ground level of 4 does not change suddenly. Therefore, neither the control board on the main body side nor the host system malfunctions.

FIG. 2 and FIG. 3 are enlarged views of a target portion in another embodiment, compared with FIG.

FIG. 2 shows an example in which the member 17 is a conductive member and the electric resistor 16 is connected between its paths. Although the example of FIG. 1 is a distributed constant in which the entire member 5 has a resistance value,
FIG. 2 shows an example of a lumped constant in which the electric resistor 16 has a resistance value. When the paper feed cassette 1 is inserted, it is gradually discharged through the electric resistor 16.

FIG. 3 shows an example in which the electric resistor 16 is mounted on the main body 10 side. The leaf spring 13 is insulated by an insulating member 19 so as not to come into direct contact with the body frame 14.

Although not shown, it is also conceivable to make the entire paper feed cassette 1 a semiconductive member. For example, the paper feed cassette 1 is molded from a plastic insulating material, and a conductive material such as carbon is mixed into the material.

[0023]

According to the present invention, static electricity generated during printing is discharged to the main body frame 14 without accumulating in the paper feed cassette 1. Further, even when the paper feed cassette 1 is inserted or removed, the accumulated static electricity is discharged through the electric resistance, so that there is no sudden change in the ground level, and therefore the control board and the host system do not malfunction.

The effect of the present invention is remarkable especially in the case of a printing machine having a high printing speed and a large amount of triboelectrification of paper, and also in a season when it is likely to generate static electricity due to seasonal drying.

[Brief description of drawings]

FIG. 1 is a structural diagram showing an embodiment of the present invention.

FIG. 2 is a partially enlarged view of another embodiment of the present invention.

FIG. 3 is a partially enlarged view of the same.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Paper feed cassette, 2 ... Cassette base, 3 ... Metal spring, 5 ... Semiconductive member, 10 ... Printer main body, 13
... conductor leaf spring, 14 ... body frame, 16 ... electrical resistor, 17 ... conductor member.

Claims (1)

[Claims] 1. A frame ground is formed of a non-conductive paper feed cassette for storing paper, a conductive member incorporated in the paper feed cassette, and a conductive member having a fitting portion with the paper feed cassette. In the mating system of the paper feed cassette that is combined with the printer body, the conductive member built into the paper feed cassette and the frame ground member of the main body should be connected by a member that has an electrical resistance value. Characteristic paper feed cassette fitting method.