JPH04282674A - Grounding structure for image forming device - Google Patents

Abstract

PURPOSE:To connect each grounding for each circuit substrate without increasing the number of parts by connecting each grounding of the circuit substrates installed in a multiple number of positions to a fixing device housing formed with a metal plate. CONSTITUTION:The housing 7 of the fixing device is formed by the metal plate and a fixing roll 2 and a heater 4 are supported by it. On the edge part of the housing 7, connection members 71 and 72 are each formed. These connection members and the groundings for the electrical circuit substrates 5 and 6 are connected. The grounding between the circuit substrate 5 and the circuit substrate 6 are electrically connected through the connection member 71, the housing 7 main body, and the connection member T2 and all become equal in potential.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grounding structure for each circuit board of an image forming apparatus in which the housing of a fixing device is formed of a metal plate.

0002

2. Description of the Related Art In recent years, image forming apparatuses have tended to be miniaturized, and due to space limitations, control systems such as a main controller installed in the image forming apparatus and drives of main motors etc. controlled by the control system In some cases, circuit boards on which electrical circuits such as systems are installed are distributed and arranged at multiple locations.

In such an image forming apparatus, if the ground between each electric circuit board is independent, there is a risk that the ground potential will vary and become susceptible to noise, etc., resulting in malfunction. , each ground of each electric circuit board is connected with a copper wire or the like.

0004

[Problems to be Solved by the Invention] However, the conventional method of connecting each ground of each electric circuit board with a copper wire or the like increases the number of parts such as copper wires, resulting in an increase in cost.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and aims to provide a ground structure for an image forming apparatus that connects each ground of each electric circuit board without increasing the number of parts.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an image forming apparatus in which a housing of a fixing device is formed of a metal plate. It is connected to the housing of the fixing device.

[0007]

According to the ground structure of the image forming apparatus constructed as described above, the respective grounds of the circuit boards disposed at a plurality of locations are connected to each other via the housing of the fixing device, and are all at the same potential.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a schematic diagram showing an example of an image forming apparatus equipped with a developing device according to the present invention. Note that the image forming apparatus main body 10 and the covers, housings, etc. of each device are made of synthetic resin or the like in order to reduce costs.

The image forming apparatus includes a contact glass 11 on which a document is placed and a document presser 12 on its upper surface, and also includes image forming means inside. Then, when copying is started, the contact glass 11 and the document presser 12 move to the left, and the right end reaches the document reading section 1, which will be described later.
When it reaches above No. 4, it is reversed and starts moving rightward to scan the document.

The image forming means is a light source 13 consisting of a lamp or the like.
, a document reading section 14 including a condensing lens, a photosensitive drum 15, a charging device 16, a developing device 17, and a transfer separation device 18.
, a cleaning section 19, a fixing device 1, and the like. The image forming apparatus main body 10 is configured to be separable into, for example, an upper main body including a photoreceptor drum 15, a developing device 17, and the like, and a lower main body (FIG. 3) including a fixing device 1 and the like.

[0011] Then, when copying is started, the light source 13
The light from the contact glass 11 is reflected by the document on the contact glass 11, and this reflected light is focused onto the photoreceptor drum 15 by the document reading section 14. On the other hand, the surface of the photoreceptor drum 15 is charged by the charging device 16 and then exposed to light from the document reading section 14 to form an electrostatic latent image.

The electrostatic latent image is developed with toner by the developing device 17 and transferred to the transfer paper fed from the transfer paper insertion slot 20 by the transfer separation device 18, and then transferred to the photosensitive drum 15.
After the transfer is completed, the transfer paper is fixed by the fixing device 1. That is, the fixing device 1 has a fixing roller 2.
and a pressure roller 3 , and the fixing roller 2 is provided with a heater 4 for heating the fixing roller 2 . and,
The fixing roller 2 and pressure roller 3 heat and melt the toner image transferred to the transfer paper using a heater 4, and apply pressure to fix the toner image on the transfer paper. After this fixing, the transfer paper is discharged to the discharge tray 21. On the other hand, the cleaning section 19 cleans the toner remaining on the surface of the photoreceptor drum 15 after the transfer.

Next, an example of the connection relationship between the electric circuit board provided in the image forming apparatus and the housing of the fixing device 1 will be explained with reference to FIGS. 1 and 3. As shown in FIG. 3, electric circuit boards 5 and 6 are provided at both ends 101 and 102 of the image forming apparatus main body 10, respectively, and these electric circuit boards 5 and 6 are equipped with control circuits such as a CPU and other components. Electrical circuits such as a main motor controlled by a control circuit, a drive circuit for the light source 13, a charging device 16, etc. are distributed in a distributed manner.

The housing 7 includes the fixing roller 2 and the heater 4.
It supports the fixing roller 2 and the heater 4, and is arranged horizontally between the ends 101 and 102 as a long object. Further, the housing 7 is formed of a metal plate such as an aluminum plate or an iron plate. That is,
Heater 4 and fixing roller 2 heated by the heater 4
are at high temperatures, so if the housing 7 that supports the fixing roller 2 and heater 4 is made of synthetic resin or the like, there is a risk that it will be deformed or deteriorated by the heat of the heater 4 or the like. For this reason, the housing 7 is made of a metal plate.

On the other hand, at a proper position at the end of the housing 7,
As shown in FIG. 1, connection members 71 and 72 are formed, respectively, and these connection members 71 and 72 are connected to the ground of the electric circuit boards 5 and 6 by screws 73 and 74, respectively. That is, as described above, since the housing 7 is formed of a metal plate such as an aluminum plate or an iron plate, it has electrical conductivity. Therefore, the ground between the electric circuit board 5 and the electric circuit board 6 is electrically connected via the connecting member 71, the housing 7 body, and the connecting member 72.

The housing 7 is fixed to the image forming apparatus main body 10 with screws 75 and 76.

In this way, since the respective grounds between the electric circuit boards 5 and 6 are connected through the metal plate that is the housing 7 of the fixing device 1, the grounds of the electric circuit boards 5 and 6 are connected separately using copper wires or the like. There is no need to do so.

In the above explanation, the electrical circuit boards are distributed in two locations, but even if the electrical circuit boards are distributed in three or more locations, each ground of each electrical circuit board can be connected via the housing 7 in the same way as in the above explanation. can. Further, in the above description, the ground of the electric circuit boards 5, 6 and the housing 7 are connected by screws 73, 74, but they may be connected by connection terminals such as crimp terminals.

[0019]

[Effects of the Invention] Since the present invention connects each ground of the circuit boards arranged at a plurality of locations through the housing of the fixing device, there is no need to connect each ground of each circuit board with a copper wire or the like. The number of parts can be reduced and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing a connection between a housing and an electric circuit board of a fixing device according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of an image forming apparatus including a fixing device according to the present invention.

FIG. 3 is a perspective view of essential parts showing the positional relationship between the housing and the electric circuit board of the fixing device according to the present invention.

[Explanation of symbols]

1 Fixing device 2 Fixing roller 3 Pressure roller 4 Heater 5, 6 Electric circuit board 7 Housing of fixing device 10 Image forming device main body 71, 72 Connection member

Claims (1)

[Claims] 1. An image forming apparatus in which a housing of a fixing device is formed of a metal plate, wherein each ground of a circuit board disposed at a plurality of locations is connected to the housing of the fixing device. Earth structure.