JPH0519553A - Image forming device - Google Patents

Abstract

PURPOSE:To improve assembling performance and to destaticize an untransferred image supporting body so as to improve image quality by supporting a case made of an insulating material by a conductive cover and fixing the conductive cover on a device main body. CONSTITUTION:An electric part 9 is disposed adjacently to the back surface side of a carrying guide plate 30, and a paper feeding cassette 20 where a recording paper P being an image supporting material is housed is disposed to be opposed to the plate 30 so as to interpose the electric part 9 between them. The electric part 9 is obtained by housing an electric circuit substrate 3 and an AC inlet 5, etc., in the case 8 made of the insulating material and the outside of the case 8 is covered with the conductive cover 7 so as to face the recording paper P of the cassette 20. Then, the insulating case 8 is covered with the conductive cover 7 made of a material having rigidity excellent in surface conductivity, for example, aluminum coating steel plate or zinc coating steel plate, and supported by the cover 7. Furthermore, the cover 7 is fixed on the frame of the device main body. Therefore, the recording paper P is carried in a state where it contacts with the cover 7, and the recording paper P is easily destaticized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, and more particularly to an image forming apparatus in which an electrical component is disposed adjacent to the back side of a conveyance guide member.

[0002]

2. Description of the Related Art Conventionally, in this type of image forming apparatus,
There are various arrangement examples of the electrical equipment unit such as the power supply unit and the controller unit, and the paper cassette depending on the device.
There was something like that shown in.

FIG. 4 is a vertical sectional view showing a laser beam printer. In the figure, the video signal input to the laser scanner unit 25 is output as laser light converted into an image signal, reflected by the reflection mirror 27 and sent into the process cartridge 26, and rotated in the direction of the arrow in the drawing to rotate in the direction of the primary charger. The latent image is written on the uniformly charged photosensitive drum 28 at 11, and the latent image is developed by the toner at the developing device 12, and reaches the transfer roller 29. On the other hand, the recording paper P, which is the uppermost image supporting material on the paper feeding cassette 20, is separated from the uppermost one by a pickup roller 21 and a separating claw (not shown) and is sent out. The toner image on the photosensitive drum 28 is transferred by the transfer roller 29 at the same timing as the photosensitive drum 28, transferred to the fixing device 31 through the paper conveyance guide 30, and fixed by the transfer roller pair 35. It is discharged to the outside of the machine. On the other hand, the transfer residual toner remaining on the photosensitive drum 28 is cleaned by the cleaning device 14. In the above description, the photosensitive drum 28, the primary charging device 11, the developing device 12, and the cleaning device 14 are housed in a case and constitute a process cartridge 26.

An AC power supply circuit for taking in AC power to the apparatus main body 1, a low voltage power supply circuit for converting AC power into DC power, D
A high-voltage power supply circuit for converting a C power supply into a high-voltage power supply, and at least one or more electric circuit parts among electric circuit parts such as a DC controller part and a controller part for controlling electric signals of the apparatus body, for example, an electric circuit board 3 Also, a power supply unit including a power supply circuit section is housed in a resin-molded power supply case 2. The paper feed cassette 20 containing the recording paper P is inserted and guided and supported by a main body frame (not shown) of the apparatus main body in a form protruding from the apparatus main body 1 in front of the paper feeding portion of the main body 1.

In this case, as an electromagnetic shield member against the noise emitted from the power supply unit, a vinyl chloride sheet or a PET sheet is vapor-deposited with aluminum or copper foil, that is, a conductive sheet (shield sheet) 4 and the circuit board 3 and It was arranged so as to be sandwiched between the power supply cases 2.

[0006]

However, the above-mentioned conventional example has the following drawbacks.

Conventionally, as shown in FIG. 4, on the inner surface of the power source case 2 made of a molded resin, as a measure against noise from the electric circuit board 3, a vinyl chloride sheet or a PET sheet is adhered with aluminum or copper foil, or The vapor-deposited conductive sheet 4 (shield sheet) was attached to the electric circuit board 3 side with the insulating surface of vinyl chloride, PET, etc. facing the power source case 2 side.

Because of the above-mentioned structure, it is difficult to assemble the electric component part, and the structure is not inexpensive.

Further, when the recording paper P is inserted into the paper feed cassette 20 in the main body of the apparatus, the recording paper is charged when the packaging is taken and the recording paper is cut, and the image is displayed without being discharged as it is. If recorded, there is a risk that the transferred image may scatter.

Therefore, the present invention solves such a problem, and an object thereof is to improve the assemblability of the electrical equipment section by changing the configuration of the power supply cover, to suppress the cost, and to further shield. An object of the present invention is to provide an image forming apparatus capable of easily improving the shield effect by simplifying the members and capable of removing the charge of the untransferred image supporting material.

[0011]

According to a first aspect of the present invention, in an image forming apparatus in which an electrical component section is disposed adjacent to the back side of a conveyance guide member for guiding an image support member, the electrical component section is an electrical component member. Is housed in an insulating material case, the outer side of the insulating material case is covered with a conductive cover, and the image supporting material cassette is disposed facing the image supporting material housing portion on the conductive cover. The image forming apparatus is characterized by supporting the case made of the insulating material and being fixed to a frame of the apparatus body.

A second invention of the present invention is the image forming apparatus according to the first invention, wherein a part of the conductive cover is a part of a conveyance guide portion of the image support material.

A third invention of the present invention is characterized in that the electrical equipment portion has an AC inlet having a ground terminal, and the conductive cover is connected to the ground terminal. The image forming apparatus according to the invention.

According to a fourth aspect of the present invention, the conveyance guide member is electrically conductive, and the conductive case and the conveyance guide member are electrically connected to each other. It is a device.

[0015]

Embodiments of the present invention will be described in detail below with reference to the drawings. The parts having the same functions as the parts described in the conventional example are denoted by the same reference numerals and the description thereof may be omitted.

FIG. 1 shows the outline of the main section of a small laser beam printer. In the figure, the conveyance guide plate 30
The electrical equipment section 9 is disposed adjacent to the back surface side of the conveyance guide plate 3
A paper feed cassette 20 containing a recording paper P as an image support material is arranged with the electrical component section 9 in between, facing 0.

The recording paper P loaded in the paper feed cassette 20 is fed by the rotation of the pickup roller 21 and the separation claw 1
5, the recording sheet P is separated and conveyed by the conveying roller 13, the skew is removed while the recording paper P is aligned with the reference surface, and a registration sensor (not shown) is operated to make the entrance conveying guide 1
7 is conveyed to the transfer roller 29 through the paper feed path 16. Simultaneously with the signal operation of the registration sensor, it is synchronized with the image information that is emitted from the laser scanner unit 25, passes through the reflection mirror 27, and is emitted onto the photosensitive drum 28 of the process cartridge 26.

The laser beam applied to the photosensitive drum 28 is developed with toner by a well-known electrophotographic process such as the conventional example, and the toner image is transferred onto the recording paper P by the transfer roller 29. The recording paper P on which the toner image has been transferred is separated from the photosensitive drum 28 and is conveyed to the fixing device 31 through the conveyance guide plate 30. The toner image on the recording paper is fixed by the fixing device 31, the paper is guided by the U-turn path-shaped transport guide 18, and is advanced by the paper discharge roller pair 35 onto the paper discharge tray 37 at the upper part of the main body. It is called "down" and discharged and loaded.

Next, a detailed description will be given of the structural arrangement relationship around the electrical equipment section 9 and the paper feed cassette 20 in the main body, which is the basis of the present invention, with reference to FIGS.

FIG. 2 shows a paper transport unit (paper transport guide plate 30),
3 is a detailed cross-sectional view of an electrical component (electrical component of power source, conductive cover 7, insulating case 8) 9 and paper feed cassette 20. FIG.
FIG. 3 is a partial detailed view of FIG. 2.

The electrical component section 9 shown in FIG. 2 is an AC power circuit for taking in an AC power source into the main body of the apparatus, a low-voltage power source circuit for converting the AC power source to the DC power source, and a low-voltage power source for converting the voltage to a high voltage. At least one electrical component of a high-voltage power supply circuit for forming an image by a process, a control circuit for controlling the apparatus main body, etc. is housed in an insulating case 8 such as one thin mold resin such as ABS resin, polycarbonate resin, etc. And is arranged in the vicinity (bottom) facing the lower surface of the paper transport guide plate 30 of the apparatus body 1. The insulating case 8 is made of vinyl chloride as another material,
It may be the one to which polyethylene terephthalate is attached. The insulating case 8 is covered with a conductive cover 7 such as a material having excellent surface conductivity and having rigidity, for example, an aluminum-coated steel plate, a zinc-coated steel plate, and the insulating case 8 is covered with the conductive cover 7. I support it. The conductive cover 7 is fixed to a frame (not shown) of the apparatus body.

Also, as shown in FIGS. 2 and 3, the conductive cover 7 is used.
Flange part 7a and the flange 3 of the paper transport guide plate 30
By holding and fixing the flange 6a of the sheet metal AC inlet cover 6 connected to the FG (frame ground) terminal of the AC inlet 5 at 0a, the paper transport guide plate 30 and the conductive cover 7 are electrically fixed. It becomes FG.

Further, as shown in FIGS. 2 and 3, the paper transport guide plate 30 and the conductive cover 7 are provided with a flange portion 30 provided on the periphery thereof.
When a and 7a come into contact with each other and are fixed, a sealed structure is formed. The recording paper P accommodating portion of the image supporting material of the paper feeding cassette 20 faces the conductive cover 7. Then, the paper feed guide portion 7b that is continuous with the paper transport guide plate 30 of the conductive cover 7.
Is a curved sheet feeding path 16 which is concave with respect to the left side and is spaced apart from the sheet feeding outlet path wall 20 a of the sheet feeding cassette 20 and the conveyance guide 17.

When the recording paper P is picked up by the paper feed cassette 20 arranged below the electrical equipment section 9, the recording paper P
Is conveyed in contact with the conductive cover 7, and since the potential of the conductive cover 7 drops to FG, the recording paper P can be destaticized at the contact.

By adopting the configuration described above, the following various advantages can be given. By fixing the electrical component 9 to the frame (not shown) of the apparatus main body 1 with the conductive cover 7 having rigidity, the conductive cover 7 serves as a reinforcing material for the frame of the apparatus main body 1 and the strength of the main body frame is improved. It got bigger. When the recording paper P is conveyed from the paper feed cassette 20 to the transfer portion, the recording paper P is conveyed while touching the conductive cover 7 that has fallen to the FG potential, so that the recording paper P is easily discharged. . Therefore, the quality of the transferred image can be easily improved. Since the electrical component is housed in a box-shaped space with a member made of a material having good surface conductivity, the outside of the electrical component forms a closed loop of the FG to prevent noise generated from the electric circuit inside the electrical component. Things can now be done easily. From the (insulation sheet + conductive sheet + insulating resin) configuration around the electrical component,
(Thin-walled insulating resin + conductive material) simplifies the structure, and the shield member, which is conventionally mounted on the inner surface of the power supply case 2, is mounted on the outer surface, which improves the assemblability.

[0026]

Since the configuration as described above is adopted,
The following effects were obtained. 1) Since the conductive cover is fixed to the frame of the main body of the apparatus, the strength of the main body frame can be easily improved and the printing quality can be improved. 2) In the paper feed cassette, since the conductive cover faces the image supporting material accommodating portion of the cassette accommodating the image supporting material, or a part of the conductive cover is a part of the conveyance guide portion of the image supporting material. When the image support material was transported, the conductive cover was effective in eliminating static electricity, preventing the transfer image from scattering and improving the image quality. 3) Since the electric component is covered with the conductive cover and the conveyance guide member, it is possible to easily obtain the effect of shielding noise generated from the electric component. 4) Since it is easy to house and assemble the electrical component in the insulating case, the electrical component can be unitized together with the insulating case, so that the assemblability of the electrical component is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an example.

FIG. 2 is a partial detailed vertical sectional view of the embodiment.

FIG. 3 is a partially exploded perspective view of FIG.

FIG. 4 is a vertical sectional view of a conventional example.

[Explanation of symbols]

1 Image forming device body 3 Electric circuit board 5 AC inlet 7 Conductive cover 8 insulating case 20 paper cassettes 30 Paper transport guide board

Claims (4)

[Claims] 1. An image forming apparatus in which an electrical component is disposed adjacent to the back side of a conveyance guide member that guides an image supporting member, wherein the electrical component is housed in a case made of an insulating material. The outside of the case is covered with a conductive cover, and the cassette of the image supporting material is disposed on the conductive cover so as to face the image supporting material accommodating portion. An image forming apparatus characterized by being fixed to a frame. 2. The image forming apparatus according to claim 1, wherein a part of the conductive cover is a part of a conveyance guide portion of the image support material. 3. The image forming apparatus according to claim 1, wherein the electrical component section has an AC inlet provided with a ground terminal, and the conductive cover is connected to the ground terminal. 4. The image forming apparatus according to claim 3, wherein the transport guide member has conductivity, and the conductive case and the transport guide member are electrically connected.