JPH08241024A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an electrical contact point for surely conducting an optional cassette feeder to a device main body. CONSTITUTION: By conducting the grounded metallic frame 24 of the device main body 2 to the metallic frame 23 of the optional cassette feeder 4 through a leaf spring 22 which is elastically displaced, a discharge action is surely executed and the generation of radiation noise and the other noise are suppressed so as to prevent a malfunction from occurring or a faulty image from being formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a facsimile, a copying machine and a printer.

[0002]

2. Description of the Related Art In recent years, an increasing number of users are demanding an image forming apparatus capable of supplying sheets of various sizes or accommodating a large number of sheets. In order to meet this demand, conventionally, an image forming apparatus has been proposed in which an optional cassette feeder can be added according to a user's request. The optional cassette feeder is usually provided with a sheet feeding cassette for accommodating sheets, a sheet feeding roller for feeding a sheet from the sheet feeding cassette, a drive transmission means for transmitting driving to the sheet feeding roller, and the like.

Further, in particular, in order to add an optional cassette feeder without increasing the installation area of the apparatus, there is one which is arranged under the apparatus main body of the image forming apparatus (for example, JP-A-60- 230164).

In an image forming apparatus equipped with such an optional cassette feeder, in order to conduct static electricity or the like generated in the optional cassette feeder to the grounded apparatus main body side, a gap between the apparatus main body and the optional cassette feeder is provided. Is provided with an electrical contact. This electrical contact is generally formed so that the metal frame on the device body side and the metal frame on the option cassette feeder side are in direct contact when the device body and the option cassette feeder are stacked.

[0005]

However, since the rigid metal frames are in contact with each other in the above-mentioned electrical contact, the contact is not sufficient, or the frames are not contacted due to deformation of the frame, etc., and stable conduction is obtained. There was a problem that it was not possible.

Due to this poor conduction, radiation noise and other noise are generated, which causes problems such as malfunction and image disturbance.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an electrical contact for surely connecting the option cassette feeder and the apparatus main body.

[0008]

SUMMARY OF THE INVENTION According to the present invention, in an image forming apparatus in which an optional sheet feeding unit can be attached to an apparatus main body, a grounded conductive portion of the apparatus main body and a conductive portion of the optional sheet feeding unit are made conductive. It is characterized in that it is connected through a flexible leaf spring.

According to the present invention, in an image forming apparatus in which optional sheet feeding units can be stacked and attached to the lower side of the apparatus main body, when the optional sheet feeding units are stacked and attached to the apparatus main body, the apparatus main body side is grounded. The conductive metal frame and the metal frame of the optional sheet feeding unit are opposed to each other, and a conductive leaf spring is provided on either one of the metal frames, and the leaf spring is pressed against the other metal frame. Is characterized in that the metal frames are electrically connected to each other.

The present invention is characterized in that the leaf spring has a plurality of spring portions having different shapes.

[0011]

According to the above construction, when the optional sheet feeding unit is attached to the main body of the apparatus, the conductive portions are electrically connected to each other through the leaf springs which are elastically displaced and press-contact with the conductive portions. The charge can be reliably removed.

Even when the optional sheet feeding units are stacked and mounted on the apparatus body, a leaf spring elastically displaced between the metallic frame of the apparatus body and the metallic frame of the optional sheet feeding unit makes pressure contact between the metallic frames. It is possible to surely remove the electric charge by connecting the switch.

If a plurality of spring portions are provided on the leaf spring,
Even if the surface of the metal frame on the pressure contact side has a shape such as a step, it can be surely conducted.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. First, the overall configuration of an image forming apparatus (laser beam printer) to which the present invention is applied will be described based on FIG.

A laser beam printer (hereinafter referred to as a printer) 1 includes an apparatus main body 2 and an optional cassette feeder 4 which is an optional sheet feeding unit mounted below the apparatus main body 2.
Composed of and. This optional cassette feeder 4
Is used by connecting to the apparatus main body 2 according to the user's request.

In the printer 1 having this structure, the paper feeding cassette 5 can be mounted on the cassette feeder 3 arranged at the lower part of the apparatus main body 2, and the paper feeding cassette 6 can be mounted on the optional cassette feeder 4.

A sheet feeding roller 7 is arranged in the cassette feeder 3, and the sheet is fed from the sheet feeding cassette 5 by the sheet feeding roller 7. A paper feed roller 8 is arranged in the optional cassette feeder 4, and the paper is fed from the paper feed cassette 6 by the paper feed roller 8.

A registration roller pair 9 is provided on the downstream side of the cassette feeders 3 and 4 in the apparatus main body 2 for feeding the sheets fed from the paper feed cassettes 5 and 6 to the image forming means at appropriate timing. There is.

The image forming means is a laser emitting device 10.
And a mirror 1 for reflecting the laser light emitted from the laser transmission device 10 and forming an image on the photosensitive drum 13.
1, a developing device 14 for developing the latent image formed on the photosensitive drum 13 with toner, a transfer roller 15 for transferring the developed toner image to a sheet, and And a fixing roller pair 16 for fixing the toner image on the sheet. The photosensitive drum 13 and the developing device 14 are arranged in the process cartridge 12 which is detachable from the apparatus main body 2.

Further, in the apparatus main body 2, a pair of conveying rollers 17 and 19 for conveying the sheet on which the image is formed by the image forming means, and a discharging roller for discharging the sheet face up on a tray (not shown). 18, a discharge tray 21 provided on the upper surface of the apparatus main body 2 is appropriately provided with a discharge roller 20 for discharging the sheet facedown.

With such a configuration, the sheets contained in the sheet feeding cassettes 5 and 6 are selected and sent out, and the image is formed by the image forming means and discharged.

A first embodiment of the present invention will be described here with reference to FIGS. 1 and 2.

On the upper surface of the optional cassette feeder 4 connected to the apparatus main body 2, a metal leaf spring 22 as an electrical contact is provided. The leaf spring 22 is fixed to a metal frame 23, which is a conductive portion of the optional cassette feeder 4, by an appropriate fixing means such as a screw or caulking, and projects above the surface on which the apparatus main body 2 is placed.

The leaf spring 22 is provided so that it can be elastically displaced vertically with respect to the fixed portion A, and the tip end side and both end sides of the surface 22A that abuts the metal frame 24 which is the conductive portion of the apparatus main body 2 are bent. Thus, the front end face 22B and the side end face 22C are formed. Since the lower end portions of the tip end surface 22B and the side end surface 22C are inside the metal frame 23 even when the leaf spring 22 is not elastically displaced (state shown in FIG. 2), the edge of the leaf spring 22 is exposed. Without
Even if the cord or each component hits the leaf spring 22, it is not damaged by the edge.

A metal frame 24 is arranged on the side of the apparatus main body 2 where the leaf springs 22 face each other. When the apparatus main body 2 and the optional cassette feeder 4 are stacked, the leaf springs 22 are attached to the metal frame 24 of the apparatus main body 2. It is pushed down by and is elastically displaced and pressed against the metal frame 24. As a result, the metal frame 23 of the option cassette feeder 4 and the metal frame 24 of the apparatus body 2 can be surely conducted through the leaf spring 22, and the static electricity generated in the option cassette feeder 4 can be passed through the apparatus body 2. Can be surely grounded.

In this embodiment, in order to increase the substantial spring length, a surface similar to the surface 22C may be bent from the surface 22B as shown in FIG. Also, face 22
The joint length of the bent portion of A and the surface 22C may be shortened to provide the cutout portion.

Next, another embodiment of the present invention will be described with reference to the drawings.

In the second embodiment shown in FIG. 3, the leaf spring 22 is fixed to the metal frame 23 of the option cassette feeder 4 in the first embodiment, whereas the leaf spring 2 is used.
5 is fixed to the metal frame 24 of the apparatus main body 2. FIG. 4 shows the leaf spring 25 of this embodiment.
Since the shape of is the same as the shape of the leaf spring 22 of the above-described embodiment, the description will be omitted. Each surface 25A, 25B of the leaf spring 25,
25C corresponds to each surface 22A, 22B, 22C of the leaf spring 22.

An opening 4a is formed in a portion of the option cassette feeder 4 facing the leaf spring 25, and the leaf spring 25 is passed through the opening 4a through a metal frame 23 arranged in a frame body formed by molding. It is designed to be pressed.

A third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, even if there is a step or the like on the metal frame with which the leaf spring is in pressure contact, it is possible to ensure conduction.

Two metal frames of the apparatus main body 2 are arranged at different heights, and in order to electrically connect each metal frame 24A, 24B and the metal frame 23 of the optional cassette feeder, they are provided at two positions of the leaf spring 26. Spring portion 26A,
26B are formed.

As shown in FIG. 6, the leaf spring 26 is formed by bending a single spring material.
6A and 26B are formed in such a shape that they are in pressure contact with the metal frames 24A and 24B, respectively. Each of the spring portions 26A and 26B has a bending structure similar to that of the above embodiment.

By configuring the leaf spring 26 in this manner, reliable conduction can be ensured. Further, it has advantages that the installation space can be made smaller and the cost is lower than the case where a pair of leaf springs are provided separately.

[0034]

As described in detail above, the present invention provides
A flat spring that elastically displaces and comes into pressure contact with the current-carrying part is used to conduct electricity between the main body of the device and the power-supplying part of the optional paper feed unit to ensure proper static elimination, thus suppressing the generation of radiated noise and other noise. It is possible to prevent the occurrence of operation and image defects.

Even when the optional sheet feeding units are stacked and mounted on the apparatus main body, the leaf spring can surely remove the electricity, and suppress the generation of radiation noise and other noises to prevent malfunctions and defective images. Can be prevented.
In this case, simply by placing the main body of the device on the optional paper feeding unit, the leaf spring automatically comes into pressure contact with the metal frame and conducts, so there is no need for special mounting structure or mounting work, and it is cheap and assembly workability is improved. Can be made.

If the leaf spring is provided with a plurality of spring portions, even if the surface of the metal frame on the pressure contact side has a shape such as a step, it can be surely conducted, so that the mounting position of the leaf spring is not limited. The degree of freedom of installation position increases.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a leaf spring which is a main part of FIG.

FIG. 3 is a perspective view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing a leaf spring which is a main part of FIG.

FIG. 5 is a perspective view showing a third embodiment of the present invention.

6 is a perspective view showing a leaf spring which is a main part of FIG.

FIG. 7 is a sectional view of a laser beam printer which is an example of an image forming apparatus to which the present invention is applied.

FIG. 8 is a perspective view showing a modification of the first embodiment of the present invention.

[Explanation of symbols]

2 Device body 4 Optional cassette feeder (optional paper feeding unit) 22, 25, 26 Leaf spring 23 Metal frame (conductive part) 24 Metal frame (conductive part)

Claims (5)

[Claims] 1. An image forming apparatus in which an optional sheet feeding unit can be attached to an apparatus main body, wherein a grounded conductive portion of the apparatus main body and a conductive portion of the optional sheet feeding unit are connected via a conductive leaf spring. An image forming apparatus characterized by the above. 2. The leaf spring is attached to one of the conductive parts, and when the optional sheet feeding unit is attached to the apparatus main body, the leaf spring is pressed by the other conductive part and elastically displaced to the other conductive part. The image forming apparatus according to claim 1, wherein the image forming apparatus is pressed. 3. An image forming apparatus capable of stacking and mounting optional sheet feeding units on the lower side of the apparatus main body, wherein when the optional sheet feeding units are stacked and mounted on the apparatus main body, the apparatus main body side is grounded. The metal frame and the metal frame of the optional sheet feeding unit are arranged so as to face each other, and a conductive leaf spring is provided on either one of the metal frames, and the leaf spring is pressed against the other metal frame so that each An image forming apparatus characterized in that the metal frames are electrically connected. 4. The image forming apparatus according to claim 3, wherein the leaf spring has a plurality of spring portions having different shapes. 5. The image forming apparatus according to claim 1, wherein the leaf spring has a plurality of bent portions for reducing the exposure of the edge portion.