JPH01123257A - recording device - Google Patents

Abstract

PURPOSE:To decrease generation and influence of electrical noises by enclosing an integrated writing unit and control members by a conductive shielding frame. CONSTITUTION:Recording paper 16 carried from the right side to the left of the device comes into contact with a recording body 1 in the lower position of said body and, therefore, the writing unit 10 and the control members such as electrical parts which are liable to generate radiation noises as well as electric parts, etc., susceptible to the influence of external noises, for example, PSU, sequence control part, controllers and video signal control parts are disposed collectively as closely to each other as possible in the position on the side opposite to the position where the recording paper comes into contact with the recording body 1, i.e., the space above the recording body 1. The writing unit and the controls members are thus capable of constituting one unit housed in one conductive shielding frame 15. The conductive shielding frame 15 is grounded directly or via other frame to the frame gland earth over the entire part of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording device, specifically a laser printer, a digital copying machine, and a facsimile machine having a control unit that generates radiation noise such as video signals and clock signals and is susceptible to external noise. This relates to recording devices such as the following.

雛】q【Tane Conventionally, an electrostatic latent image is formed on a photoreceptor by exposure using an optical signal from an optical writing unit, and a developed image is formed by development.
Electrophotographic recording devices are used that form images on recording paper through transfer and fixing, as shown in Figure 1.
A video control unit that sends and controls video signals to the writing unit; a signal control unit that includes a controller that sends code/video signals to the video control unit; and a signal control unit that controls charging, exposure, and
A conventional recording apparatus is equipped with a sequence control section that performs sequence control of an image forming means that performs development, etc. and transfer/fixing of recording paper, and a PSU that supplies power to each part of the apparatus.

In conventional recording apparatuses, in order to secure a paper conveyance path and downsize the entire apparatus, electrical components are arranged in a dispersed manner, and each electrical component is connected with a harness.

When high-speed video signals and clock signals are used in control units that include electrical components, radiated noise is generated.
This can cause radio wave interference, and a structure in which electrical appliances are distributed and connected to a harness is susceptible to external noise, such as static electricity caused by human operation, and external noise, which can easily cause malfunctions.
This causes data loss. The portion included within frame A in the block diagram collectively illustrated in FIG. 1 is a portion that tends to generate radiation noise and is susceptible to the influence of external noise.

In order to reduce the generation of radiated noise and eliminate the effects of external noise, use a ferrite core or shielded cable for the harness, use a multilayer laminate, ferrite beads, etc. for the control board, and use a sheet metal cover or conductive material for the exterior. Countermeasures such as applying paint are taken, but this greatly increases the cost, and since the electrical components are scattered, complete countermeasures cannot be taken, and the above problems are still unresolved. No, no.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an inexpensive recording device that is resistant to external noise, generates little radiation noise.

In order to achieve the above object, the present invention provides a writing unit and a control unit at a position opposite to the support or movement center of the recording body from the position where the recording paper comes into contact with the recording body for transfer. are arranged close together and surrounded by a conductive shield frame, and the conductive shield frame is grounded.

The structure and operation of the present invention will be explained in detail based on the embodiment shown in the drawings.

FIG. 2 shows an example of a laser printer as an example of a recording apparatus according to the present invention. The photosensitive drum l as a recording medium, the charger 2, the developing device 3, the transfer charger 4, the cleaning device 5, the paper feed device 6, the fixing device 7, the paper ejection tray 8, and the paper transport path 9 included in the image forming means are It is formed similarly to a known recording device.

The position where the recording paper contacts the recording medium 1, for example, the photosensitive drum for transfer, that is, the position of the transfer charger 4 is as follows:
The writing unit 10 is arranged at a position substantially opposite to the support center or the movement center of the recording medium 1. An optical signal from the writing unit 10 is projected onto the recording medium 1 at an exposure position 211 between the charger 2 and the developing device 3 .

For example, the configuration shown in FIG. 1 can be used as it is as a control section for controlling the writing unit 10 and the image forming means. The PSU 12, the engine board 13 incorporating a sequence control unit, a video control unit, etc., and the controller board 14 incorporating a controller, etc. are arranged near the writing unit 10.
and are surrounded by one conductive shield frame 15. The conductive shield frame 15 may be formed of a plurality of metal plates, a conductive sheet, a metal casting, or the like.

In FIG. 2, the recording paper 16 that is conveyed from the right side of the apparatus to the left touches the recording body 1 at a lower position, so the recording paper 16 contacts the recording body 1 at a position opposite to the position where the recording paper makes contact with the recording body 1. In the space above 1, the writing unit 10 and control members, especially electrical equipment that easily generates radiation noise and electrical equipment that is susceptible to external noise, such as a PSU, a sequence control unit, a controller, and a video signal control unit, are placed. Place them as close together as possible. Thereby, the writing unit and the control member can constitute one unit housed within one conductive shield frame 15. Since each electrical component is placed close to each other, the harness connecting each component is either short or directly connected to each other. The conductive shield frame 15 is grounded to the frame ground of the entire device, either directly or via another frame.

As a modification of FIG. 2, as shown in FIG. 3, a conductive shield frame 15 is arranged below the recording medium 1, contrary to FIG. They can also be transported so that they are in contact with each other. Same as Figure 1.
Or corresponding parts are given the same reference numerals, and detailed explanations are omitted.

The conductive shield frame housing the writing unit and the control member in one unit is not limited to being placed above or below the photoreceptor 1 as in the examples shown in FIGS. 2 and 3, but is placed between the recording medium and the conductive shield frame. The contact position of the recording paper may be, for example, anywhere as long as it is substantially opposite to the transfer position.

Therefore, it is determined by the conveyance path of the recording paper.

A modified example will be shown in the fourth part. FIG. 4A is an example in which the recording paper is placed on the right side of the recording medium, FIG. 4 is a modification of FIG. 3 in which the path of the recording paper is different, and FIG. 4C is a modification of FIG. 4A. The fourth diagram is an example in which the contact position of the recording paper is on the left side of the recording medium, FIG. 4E is a modification of the fourth diagram, and FIG. 4F is a modification of FIG. 4C.

The arrangement of the conductive shield frame that houses the writing unit and the control member in one unit is clear from the drawings, so a description thereof will be omitted.

According to the present invention, the writing unit and the control section are centrally configured, and each member of the control member can be connected directly or by a short harness, and the generation of radiation noise and the influence of external noise can be prevented.

By surrounding the integrated writing unit and control member with a conductive shield frame, it has become possible to reliably reduce the generation and influence of electrical noise compared to the conventional case where they are dispersed.

According to the present invention, the writing unit and the control member can be placed together and shielded, so less material is required for the shield frame, the shape can be made simple, and it is much cheaper than the conventional one. was gotten.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the relationship between the recording medium, the image forming device, the writing unit, and the control member of the recording device, FIG. 2 is a schematic cross-sectional view of the recording device according to the present invention, and FIG. 3 is a separate diagram. FIGS. 4A-4F are schematic cross-sectional views of other embodiments of the present invention. 1... Recording body 10... Writing unit 15
...Conductive shield frame Fig. 1 Bunonta Fig. 4

Claims (1)

[Scope of Claims] A recording medium, a writing unit that forms an electrostatic latent image on the recording medium, an image forming means that forms an image on the recording medium, and control that controls the writing unit and the image forming means. In a recording device having a section, the writing unit and each part of the control section are located close to each other at a position opposite to the support or movement center of the recording body from the position where the recording paper contacts the recording body for transfer. A recording device characterized in that the recording devices are arranged together and surrounded by a conductive shield frame, and the conductive shield frame is grounded.