JPS6341327A - Sheet feed device for picture forming device - Google Patents

Abstract

PURPOSE:To prevent turbulence of a picture due to discharge, by a method wherein a resistor having a resistance value of 10<2>-10<10>OMEGA is inserted in the earthing circuit of a sheet placing plate formed with a sheet placing plate in a sheet feed cassette and an earthing device connected to the pressurizing plate of a sheet feed cassette locking device. CONSTITUTION:A sheet feed cassette 2 is inserted in a sheet feed cassette locking device 1 mounted to the sheet feed port of the body of a picture forming device. Projected parts 103a of the tip parts of a pair of lock levers 103 on both sides of the locking device 1 are locked to recessed parts 203b on both sides of the cassette 2 to secure the cassette 2. Simultanuously, a pressurizing plate 104 of the locking device 1 enters through the front of the cassette 2 to push up a sheet laminating plate 204 in the cassette 2 to pressure a paper P between the nip formed between the sheet laminating plate and a sheet feed roller 3. A semicircular column body 104d made of conductive plastic having a resistance value of 10<2>-10<10>OMEGA is located to the tip of the pressurizing plate 104, and a shaft 102 of the locking lever 103 is earthed by means of 106. This constitution, when the cassette is remounted to the picture forming device, gradually discharges charge, accumulated in the sheet laminating plate, to prevent turbulance of a picture.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a paper feeding device in an image forming apparatus such as an electrophotographic device, and more specifically, in a paper feeding device using a paper feeding cassette, the present invention relates to a paper feeding device that uses a paper feeding cassette. The present invention relates to a paper feeding device configured to prevent the adverse effects of discharge on an image forming apparatus.

[Background of the invention]

As is well known, a paper feed device installed in an image forming device such as an electrophotographic device includes a paper feed cassette for storing sheets of paper for image recording in a stacked state, and and a paper feed cassette locking device provided within the main body of the image forming apparatus for locking the cassette.

Start operation of the image forming apparatus with the paper feed cassette (hereinafter abbreviated as cassette) being locked in the paper feed cassette locking device (hereinafter abbreviated as cassette locking device). Then, the paper feed roller in the image forming apparatus pulls out the topmost paper sheets of the paper stack (paper stack) in the cassette one by one and sends them to the image recording section (transfer section) in the image forming apparatus. The image is recorded on the paper.

When the topmost paper in the paper stack is pulled out of the cassette by the paper feed roller in the above state, the paper being pulled out and the paper directly below it rub against each other, so that the surface of both papers is is charged with electric charge. When such a paper pull-out operation is repeated many times, a multi-leaf charge accumulates in the paper stack, and the charge is eventually transferred to the metal paper stack on which the paper stack is loaded. Flow into the board. While the cassette is in use, the metal pressure plate, which is a part of the paper feed cassette locking device, is pressed against the paper stacking plate, so the electric charge flowing into the paper stacking plate will cause the charge to flow into the paper stacking plate. After flowing through the image forming apparatus to various parts of the image forming apparatus, it is discharged to the ground through a ground wire provided in the image forming apparatus.

However, if the cassette is removed from the image forming apparatus when a large amount of unused paper remains in the cassette, the charges accumulated on the paper stacking plate in the cassette will have nowhere to escape.

The paper remains accumulated on the paper stacking board. Therefore, when the cassette is reinstalled into the image forming apparatus, the charges accumulated on the paper stacking plate are released at once, and after the charges flow into the image forming apparatus via the pressure plate, It is discharged to the earth through a ground wire within the device.

Conventionally, the above-mentioned charge discharge that occurs when a cassette is reinstalled into an image forming apparatus did not have a large negative impact on the operation of the image forming apparatus, but recent image forming apparatuses have a Since the device is equipped with ICs, microcomputers, etc. that operate on weak currents and voltages, if a large amount of charge is released from the paper feed cassette as described above, the control device will be affected by noise due to the charge release. As a result, there is a possibility that the image forming apparatus may not be able to exhibit the desired performance.

[Purpose of the invention]

An object of the present invention is to provide an improved paper feeding device that can prevent a large amount of charge from being discharged from the paper cassette into an image forming apparatus at once when the paper feeding cassette is reinstalled.

[Summary of the invention]

In the improved paper feeding device according to the present invention, a paper stacking plate in a paper feeding cassette, a pressure plate provided on a paper feeding cassette locking device in an image forming apparatus, and a pressure plate connected directly or indirectly to the pressure plate. A grounding circuit for the paper stacking plate is constructed by a grounding means having a resistance value of 10 to 1010 Ω, and at least a part of the pressure plate, the paper stacking plate, and the grounding means are It is characterized by being made of a resistor.

The paper feeding device according to the present invention was developed based on the results of various experiments to prevent the adverse effects of discharge from within the paper feeding cassette. In the paper feeding device, by setting the resistance of the discharge path of the accumulated charges in the paper feeding cassette to the above value, the discharge of the accumulated charges is suppressed or the discharge time is extended, and as a result, the image forming apparatus It is possible to prevent malfunctions from occurring.

:Embodiments of the invention] Examples of the invention will be described below with reference to the drawings.

1 to 3 are diagrams showing a first embodiment of the present invention. FIG. 1 also shows a paper feeding cassette locking device 1 provided in a housing of an image forming apparatus in a paper feeding apparatus of the present invention;
FIG. 2 is a perspective view showing a front end portion of a paper feed cassette 2 detachably locked to the paper feed cassette locking device 1;

As shown in FIG. 1, the paper feed cassette locking device 1 is composed of various members described below. That is, a pair of bearing members 1o1. fixed within the housing of one image forming apparatus.
A rotating shaft 1o2° whose both ends are rotatably supported by the bearing member 101; a locking lever 1o3° fixed to both ends of the rotating shaft 102 for locking a paper feed cassette 2 to be described later; A pair of support parts 104a are loosely fitted to the moving shaft 102,
A pressure plate 104 is rotatably supported relative to the rotation shaft 102 via the support portion 104a. A coil spring 105 whose one end is locked to the rotation shaft 102 and whose other end is engaged with the hook 104b of the pressure plate 104. A paper feed cassette locking device is provided by various members such as a grounding means 106 that elastically slides on the outer peripheral surface of the rotation shaft 102 and electrically grounds the pressure plate 104 via the rotation shaft 102. 1 is configured.

Locking lever 10 that can rotate integrally with rotation shaft 102
3 has a tip protrusion 103a at its tip that fits into a side edge recess of a paper feed cassette 2, which will be described later. Rotation axis 10
The bearing member 101 that rotatably supports the paper feed cassette 2 is provided with a first stop horn 4101a so that the lock/f-103 can stand still at a predetermined angle of inclination. When the cassette is pulled out from the cassette locking device 1, the locking lever 103 remains stationary at a position where it is pressed against the stylus 4101m.

A pin 102a is provided protruding from the outer peripheral surface of the rotation shaft 102, and a hook 105a at one end of a coil spring 105 fitted on the rotation shaft 102 is engaged with the pin 102a. The engaging portion 105b at the other end is the pressure plate 104
The hook 104b can be engaged with the hook 104b erected thereon.

When the paper feed cassette 2 is not inserted into the locking device 1 as shown in FIG.
04b receives an upward force from the engaging portion 105b of the coil spring 105.

Another pin 102b is provided on the outer circumferential surface of the rotation shaft 102, and this pin 102b is attached to the pressure plate 1 in the state shown in FIG.
It is pressed against a second stopper 104C erected at 04. On the other hand, the paper feed cassette 2 has an opening 20 in the center.
1a is formed on the front plate 201. A bottom plate 202 with an opening 202a connected to the opening 201a formed in the front end portion, a sloped surface 203a on the front surface that engages with the tip of the locking lever 103, and a top surface near the front end with the locking lever 103. A side plate 203 having a recess 203b into which the tip projection 103m fits, and a filter paper stacking plate 204 that covers the opening 202 of the bottom plate 202 and can be raised and lowered on the bottom plate 202. are doing. The paper loading board 204
is made of a conductive material such as metal, but the other front plate, bottom plate, and side plates are all made of a non-conductive material.

As explained in FIGS. 2 and 3, an opening 201a formed in the center of the front plate 201 allows the paper feed roller 3 disposed inside the casing of the image forming apparatus to enter the paper feed cassette 2. This is an opening for the paper feed roller to enter. In addition, an opening 2 formed at the center of the front end of the bottom plate 202
Reference numeral 02a denotes a pressure plate entry opening that allows the pressure plate 104 of the paper feed cassette locking device 1 to enter into the paper feed cassette 2.

In the first embodiment of the present invention shown in FIGS. 1 to 3, the upper surface of the tip of the pressure plate 104 has an electrical resistance value of 102 to 10 Ω.
A semi-cylindrical resistor 104 made of conductive plastic.
It is characterized by forming a d. According to the inventor's experiments, members having such electrical resistance values are used for the pressure plate 1041, the paper stacking plate 204, and the like. It has been confirmed that by providing a grounding circuit for the paper stacking board consisting of the grounding means 106 and the grounding means 106, sudden discharge from the paper stacking board 204 to the image forming apparatus can be effectively suppressed. The first embodiment of the present invention shows a case where a resistor 104d having the above-mentioned n-air resistance value is provided at the tip of the pressure plate 104.

Figure 2 shows how many sheets of paper P are left over from the previous use.
This figure shows a state before the paper feed cassette 2 containing K is attached to the paper feed cassette locking device 1 inside the image forming apparatus housing. In this state, the tip of the locking lever 103 is urged downward by the coil spring 105, and the rotation shaft 102
The pin 102b is the stopper base 104c of the pressure plate 104.
is in contact with.

When the paper cassette 2 is moved in the direction of the arrow A shown in the figure in order to lock the paper cassette 2 in the paper cassette locking device 1, the tip of the locking lever 103 touches the side plate 20 of the cassette 2.
This corresponds to the front inclined surface 203a of No. 3. Then, when the cassette 2 is further propelled in the direction of the arrow, the tip of the lever 103 moves upward along the inclined surface 203a, and at the same time, the lever 103 rotates counterclockwise with respect to the axis of the rotation shaft 102. At the same time, the rotation shaft 102 is also rotated counterclockwise.

Note that when the tip of the lever 103 engages with the inclined surface 203a, the pressure plate 104 enters the cassette 2 through the opening 202a provided in the bottom plate 202 of the cassette 2, and the pressure plate 104 Resistor 1 installed at the tip
04d is brought into contact with the lower surface of the paper stacking board 204, and this state is maintained thereafter.

On the other hand, at the same time as the pressure plate 104 enters the cassette 2, the paper feed roller 3 in the image forming apparatus also enters the cassette 2 through the opening 201 & of the front plate 201 of the cassette 2, and the paper P in the cassette 2 is positioned above.

When the locking lever 103 is rotated counterclockwise, the rotation axis 1
02 is also rotated counterclockwise, and at this time, the coil spring 105 fitted to the rotation shaft 102 is also twisted counterclockwise. Therefore, since the engaging portion 105b of the coil spring 105 is rotated counterclockwise, a counterclockwise torque is also applied to the pressure plate 104 via the rib portion 104b that engages with the retaining portion 105b. As a result, the resistor 104d is pressed against the lower surface of the paper stacking plate 204, and acts to push up the paper stacking plate 204.

When the paper feed cassette 2 is further propelled in the direction of the arrow, the tip protrusion 103 & of the locking lever 103 touches the side plate 2 of the cassette 2.
03 and then raise the protrusion 1 as shown in FIG.
03a is inserted into the recess 203b on the upper surface of the side plate 203, whereupon the cassette 2 cannot be further propelled in the direction of the arrow, and the cassette 2 is locked with the locking device 1. At this time, the pressure plate 104
Since the paper stacking plate 204 is pushed upward by the force of 05, the paper P in the cassette 2 is pressed against the circumferential surface of the paper feed roller 3, making it possible to start paper feeding.

As shown in Figure 3, the paper feed cassette 2 is a paper feed cassette.

When the paper feeding device is completed by being locked in the locking device 1, the paper stacking plate 204, the pressure plate 104, and the grounding means 106 form a grounding circuit for the paper stacking plate.

In the first embodiment of the present invention shown in FIGS. 1 to 3, a resistor 104d made of conductive plastic and having a resistance value of 102 to 1010 Ω is used as a circuit component of the grounding circuit on a pressure plate 104 and a paper stacking plate 204. Since it is provided in the contact area with the paper stack plate 204, even when the paper feed cassette 2 containing unused sheets P is reinstalled in the image forming apparatus as shown in FIGS. The charges accumulated in the image forming apparatus are not suddenly released to the image forming apparatus, and therefore there is no risk of adversely affecting electronic circuits and the like within the image forming apparatus.

FIG. 4 is a schematic diagram showing the configuration of a second embodiment of the present invention. In this second embodiment, an all-metal pressure plate 1041 that does not have the resistor 104d as described above is used, and as a grounding means for grounding the rotating shaft 102, the resistance value is from lo2 to
A grounding circuit is constructed using a grounding member 1061 with a resistance of 10Ω. In this embodiment, as in the first embodiment, it is possible to effectively prevent sudden charge discharge from the paper stacking plate 204 to the image forming apparatus when the paper feed cassette 2 is reinstalled.

In a third embodiment of the invention shown in FIG. 5, a grounding member 106. In place of using
while grounding the paper loading plate 204. with a resistance value of 102 to 10 Ω. By equipping the paper feed cassette 2 in the paper feed cassette 2, a grounding circuit for the paper stacking plate is constructed. It has been confirmed that in this example, as in the previous examples, it is possible to prevent sudden charge discharge from the paper stacking plate in the cassette 2 when the paper feed cassette 2 is reinstalled in the image forming apparatus.

〔Effect of the invention〕

As explained above, in the paper feeding device of the present invention, the paper stacking plate in the paper feeding cassette, the pressure plate in the paper feeding cassette locking device, and the grounding means of the paper feeding cassette locking device constitute the paper feeding device. In the grounding circuit for the paper stacking board, some of the components of the circuit are configured as resistors with a resistance value of 102 to 1010 Ω, so that the person who reinstalls the paper feed cassette in the image forming apparatus can It is possible to prevent sudden discharge of charge from the plate to the image forming device, and as a result, it is possible to eliminate the adverse effects of electrostatic discharge on the image forming device.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of a paper feeding device according to a first embodiment of the present invention, and FIG. 2 is a perspective view of the device shown in FIG. Fig. 3 is a diagram showing the state in which the paper feed device is completed by locking the paper feed cassette 2 to the paper feed cassette locking device in the first embodiment, and Fig. 4 is a view showing the state in which the paper feed device is completed in the first embodiment. Figure 9 shows the second embodiment of
FIG. 5 is a diagram showing a third embodiment of the present invention. 1...Paper cassette locking device

Claims (1)

[Scope of Claims] A feeding device for an image forming apparatus that includes a paper feeding cassette locking device built into the main body of the image forming device, and a paper feeding cassette detachably locked to the paper feeding cassette locking device. In the paper device, a conductive paper stacking plate provided in the paper feeding cassette, and the paper feeding plate that engages with the paper stacking plate when the paper feeding cassette is locked in the paper feeding cassette locking device. A grounding circuit for the paper feed cassette is constituted by a conductive pressure plate in the cassette locking device and a grounding means in the paper feed cassette locking device that directly or indirectly grounds the pressure plate. , at least a part of the paper loading plate, the pressure plate, and the grounding means included in the grounding circuit, with a resistance of 10^2 to 10^1^0 Ω.
1. A paper feeding device for an image forming apparatus, characterized in that the paper feeding device is configured as a resistor having a resistance value of .