JPH07319301A - Transfer device in image forming device - Google Patents

Abstract

PURPOSE:To simplify the work for attaching a transfer roller facing the surface of a photoreceptor drum and a high voltage board for applying a high voltage to the transfer roller, etc., in an electrostatic image forming device. CONSTITUTION:A transfer unit base 8 is formed into a shape like an open case by the rear surface of a base plate 8a, a supporting part 31 for supporting the transfer roller 9 and a passage guiding member 32 for making the passage of a paper sheet P smooth are provided on the surface side of the base plate 8a and engaging pawls 39 are provided on the inside surfaces of base part side plates 8b and attaining support so as to cover almost all the wide range surface of the high voltage board 26 in a case part. Moreover, a coil terminal 36 in elastically pressurized contact with a plate like electrode part 38 formed on the wide range surface of the high voltage board 26 is made to face the rear surface side of the base plate 8a and the terminal 36 is connected to a wiring 37 connected to the transfer roller 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device in an electrostatographic image forming apparatus such as a laser printer, a copying machine or a facsimile machine.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-3-16657.
As disclosed in Japanese Patent Laid-Open No. 3 (1993), an optical image signal is applied to the surface of an image carrier that is uniformly charged to form an electrostatic latent image, and charged toner is applied to the latent image to form a toner image. After forming
Applying a high transfer voltage to the transfer roller while passing the paper through the transfer part where the transfer roller is in contact with the surface of the image carrier,
An image forming apparatus is known in which a toner image is transferred onto a sheet and then the sheet is heated and pressed to fix the toner image on the sheet to form an image.

In this case, conventionally, a member for supporting the transfer roller, a guide member for guiding the paper coming out of the transfer portion toward the fixing device, and a substrate having a high voltage circuit for applying a transfer voltage are used. , Were separately attached to the main body frame of the image forming apparatus.

[0004]

However, with this configuration, it takes a lot of time to attach and disassemble the above-mentioned components, and additionally, a conductive wire to be applied to the transfer roller from the high-voltage board is separately connected. It has to be connected and disconnected, which is troublesome. Furthermore, if a paper jam occurs during use of the image forming apparatus, the operator inserts his / her hand into the transfer portion to pull out the paper, so that the hand or the like should not touch the high-voltage board. Therefore, conventionally, since the surface of the high-voltage board is covered with an insulating cover body, the number of required parts is increased and the manufacturing cost is increased. .

The present invention has been made to solve the above technical problems, and facilitates the mounting and disassembling work,
Moreover, it is an object of the present invention to provide a transfer device in a safe image forming apparatus, which reduces manufacturing cost.

[0006]

In order to achieve the above object, a transfer device in an image forming apparatus according to the present invention transfers a toner image onto a transfer member which faces a surface of an image carrier which rotates and carries a toner image. In an image forming apparatus configured to transfer a toner image to a recording medium such as a sheet that passes a transfer member by applying a voltage, a support portion of the transfer member and a passage guide member for the recording medium are formed on the surface. On the back surface side of the transfer unit table, there is provided a supporting means for attaching and supporting an edge portion of the high voltage substrate for applying a transfer voltage to the transfer member.

According to a second aspect of the present invention, in the transfer device of the image forming apparatus according to the first aspect, the transfer unit base is formed in a box shape with an open back surface, and the high voltage substrate is formed in the box portion. While the wide surface is configured to be substantially covered, the supporting means is provided on the inner surface of the box portion. Further, the invention according to claim 3 is the transfer device in the image forming apparatus according to claim 1 or 2,
On the back surface side of the transfer unit base, terminal means for elastically pressing and contacting the electrode portion formed on the wide surface of the high voltage substrate is exposed, and the terminal means and the wiring connected to the transfer member are connected. It was done.

[0008]

EXAMPLES Next, examples embodying the present invention will be described. FIG. 1 is a schematic sectional side view of a laser beam printer 1 as an image forming apparatus, and FIG. 2 is a sectional side view of a transfer device. In the printer 1 of this embodiment, a paper feed cassette 3 as a paper feed unit is detachably attached to a lower portion of a main body case 2, and recording sheets stacked in the paper feed cassette 3 by a plurality of paper feed rollers 4 and the like. The paper P as a medium is separated one by one, and between the image forming unit 7 and the transfer unit base 8 having a transfer roller 9 as a transfer member via the paper guide plate 5 and the feeding roller pair 6. Sent.

The image forming unit 7 includes a photosensitive drum 10.
A developing device unit 11 including a toner tank and a developing roller 12, and a charging device 13 including a charging roller,
A cleaning (not shown) device and the like are housed in a case as one kit to form a single unit. A scanner unit 22 including a laser emitting section 23, a lens 24, a reflecting mirror 25, and the like is arranged above the image forming unit 7, and below the transfer unit table 8 the charging device 13 and the transfer roller 9 are arranged. A high voltage substrate 26 for applying a high voltage is arranged, and a control substrate 27 is arranged below the fixing unit 15.

The surface of the photosensitive drum 10 precharged by the charging device 13 is irradiated with light emitted from the scanner unit 22 in accordance with image data transmitted from an external device such as a host computer (not shown). The electrostatic latent image is formed on the surface of the photoconductor drum 10, and then the developing roller 12 is rotated to supply the charged powdery toner to visualize the latent image. After that, the toner image is transferred onto the paper P supplied between the photosensitive drum 10 and the transfer roller 9. Next, the sheet P that is conveyed by sliding on the sheet passage guide member 32 on the front surface side (upper side) of the transfer unit table 8 which will be described in detail later is fixed in the fixing unit 15.
Then, heat and pressure are applied to the transferred image to fix the toner image on the sheet by passing between the heating roller 16 and the pressing roller 17. After that, the paper is discharged to the paper tray 21 on the upper surface of the main body case 2 via the paper discharge guide plate 18, the intermediate roller pair 19, and the paper discharge roller pair 20.

An embodiment of the transfer device of the present invention will be described below with reference to FIGS. 1 and 2. The transfer unit base 8 is formed by injection molding with a synthetic resin having an electrical insulation property such as ABS resin. As shown in FIG. 2, one side of the upper surface of the base plate 8a of the transfer unit base 8 is formed as shown in FIG. , A bifurcated groove-shaped support portion 31 for vertically supporting the bearings (not shown) at the left and right ends of the conductive (metal) shaft of the transfer roller 9 made of a conductive sponge, etc. To project. The bearing is configured such that the transfer roller 9 is pressed against the lower circumferential surface of the photosensitive drum 10 by a biasing means (not shown) such as a metallic (conductive) coil. A plurality of fin-shaped passage guide members 32 for guiding the paper P, which has passed through the transfer portion, toward the fixing unit 15 are integrally formed on the stepped portion on the base plate 8a adjacent to the support portion 31 in an upward direction. It is protruding. At least one of the bearings is made of a conductive material (metal or a composite member in which carbon black, graphite, and metal powder are dispersed in a synthetic resin).

On the other hand, as shown in FIGS. 1 and 2, a plurality of supporting legs 33, 33 are provided from the base plate 8a of the transfer unit base 8 as a supporting means for attaching and supporting the edge portion of the high voltage substrate 26. Are projected downward, and the engaging claws 3 for locking the edges of the high-voltage board 26 are provided at the lower ends of the support legs 32.
4 is provided. As a result, in a state where the high-voltage board 26 is attached to the back surface side of the transfer unit base 8 in advance so that it cannot be removed,
The transfer unit base 8 can be mounted at a predetermined location.

FIG. 3 shows another embodiment, and the basic constitution is almost the same as that of the above embodiment. Therefore, only different parts will be described. The transfer unit base 8 is formed in a box shape that opens downward, and the high voltage substrate 26 is completely covered in the box portion. And
Of the four side plates 8b integrally projecting downward from the base plate 8a of the transfer unit base 8, at least two side plates 8b facing each other are used as supporting means for supporting the edge portion of the high-voltage board 26.

In this case, on the inner surface of the side plate 8b, there is formed an engaging claw 39 which can be fitted and engaged when the high voltage board 26 is pushed into the box portion. According to this embodiment, similarly to the above-described embodiments, the transfer unit base 8 can be mounted at a predetermined position while the high-voltage board 26 is mounted on the back surface side of the transfer unit base 8 in advance so that it cannot be removed. At the same time, since the high-voltage board 26 is completely surrounded by the box on the back side of the transfer unit base 8 having an electric insulation property, even if an operator touches the passage guide member 32 to remove the paper jam, an electric shock will occur. It is safe without.

Further, as shown in FIG. 3, the inner diameter of the electrically insulating cylindrical guide member 35 projecting downward from the base plate 8a of the transfer unit base 8 is electrically conductive (metallic). Etc.) and the coil-shaped terminal 36 is arranged, and one end of the terminal 36 is connected to the wiring 37 connected to the bearing 30 (or the biasing means 30a) having the conductivity, while the other end of the terminal 36 ( The lower end) is pressed into contact with the flat plate-shaped electrode portion 38 formed on the upper surface of the high voltage substrate 26. According to this structure, the work of mounting the high-voltage board 26 on the rear surface side of the transfer unit base 8 and the wiring connection work for supplying power to the transfer roller 9 are completed at the same time, so that the mounting work can be extremely simplified. Produce an effect.

At a position adjacent to the support portion 31, a static elimination plate 40 for removing the electrostatic charge charged on the sheet P passing through the transfer portion is erected upward, and a base plate adjacent thereto. A flat auxiliary charge-eliminating plate 41 is provided on the stepped portion on 8a.
Are arranged, the auxiliary static elimination plate 41 and the static elimination plate 40 are electrically connected at the contact portion 42, and the static elimination plate 40 and the like are connected to a ground (potential 0) not shown. As a result, it is possible to efficiently remove the electrostatic charge charged on the paper P when passing through the upper portion of the static elimination plate 40 and the auxiliary static elimination plate 41.

It goes without saying that the present invention can also be applied to a transfer device in an electrostatic electrophotographic image forming apparatus such as a facsimile or a copying machine.

[0018]

As described above, claim 1
A transfer device in an image forming apparatus according to the invention described above applies a transfer voltage to a transfer member that faces a surface of an image carrier that carries and rotates a toner image, and a toner image is applied to a recording medium such as a sheet that passes through the transfer member. In an image forming apparatus configured to transfer a transfer member, a transfer unit table having a support member for a transfer member and a passage guide member for a recording medium formed on the front surface is used for applying a transfer voltage to the transfer member. It is provided with a support means for mounting and supporting the edge portion of the high voltage board.

Therefore, according to the present invention, the transfer unit base is provided with the supporting portion for supporting the transfer member, the passage guide member for facilitating the passage of the recording medium, and the supporting means. , The number of parts is reduced, the transfer member is mounted on the supporting portion, the high-voltage board is mounted on the back side of the transfer unit base in advance via the supporting means, and then the transfer unit base is mounted on the predetermined position. In this way, it is possible to perform the mounting work of these parts all at once, and the disassembling work can be performed at one place, and the labor of assembling and disassembling work can be greatly simplified, and the manufacturing cost can be significantly reduced. .

According to a second aspect of the present invention, in the transfer device of the image forming apparatus according to the first aspect, the transfer unit base is formed in a box shape having an open back surface, and the high voltage substrate is formed in the box portion. While the wide surface is configured to be substantially covered, the supporting means is provided on the inner surface of the box portion. Therefore, according to the present invention, in addition to the operation and effect of the invention described in claim 1, the wide surface on which the electronic components are mounted in the high-voltage board mounted on the back side of the transfer unit base is completely covered. Even when an operator brings his or her hand close to the transfer unit base in the event of paper jam, it is possible to prevent an accident such as electric shock and it is safe.

Furthermore, the invention according to claim 3 is the same as claim 1.
Alternatively, in the transfer device of the image forming apparatus according to claim 2, terminal means for elastically pressing and contacting the electrode portion formed on the wide surface of the high voltage substrate is provided on the rear surface side of the transfer unit base. The terminal means and the wiring connected to the transfer member are connected. According to this invention, in addition to the operation and effect of the invention according to claim 1 or 2, in addition to the work of mounting the high voltage substrate on the back side of the transfer unit base, the terminals projected from the back side of the transfer unit base are also provided. Since the means is pressed into contact with the electrode part of the wide surface of the high voltage board and electrically connected, the work of mounting and removing the high voltage board and the wiring connection work can be performed at the same time, and the assembly and disassembly work is further improved. The effect is that it becomes easy.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a laser printer.

FIG. 2 is a side sectional view of a main part of a transfer device.

FIG. 3 is a side sectional view of another embodiment.

[Explanation of symbols]

 1 Printer 2 Main Body Case 7 Image Forming Unit 8 Transfer Unit Base 8a Base Plate 8b Side Plate 10 Photosensitive Drum 11 Developing Device Unit 15 Fixing Unit 26 High Voltage Substrate 30 Bearing 31 Support Portion 32 Passage Guide Member 33 Support Foot 34, 39 Engagement Claw 37 Wiring 38 Electrode

Claims (3)

[Claims] 1. A transfer member is configured to transfer a toner image onto a recording medium such as a sheet of paper which passes through the transfer member by applying a transfer voltage to a transfer member which faces the surface of an image bearing member which carries and rotates the toner image. In the image forming apparatus, on the back side of the transfer unit base having the support portion of the transfer member and the passage guide member of the recording medium formed on the front surface, an edge of a high voltage substrate for applying a transfer voltage to the transfer member. A transfer device in an image forming apparatus, comprising a supporting means for mounting and supporting a unit. 2. The transfer unit base is formed in a box shape with an open back surface, and the wide surface of the high-voltage board is substantially covered in the box portion, while the supporting means is provided on the inner surface of the box portion. The transfer device in the image forming apparatus according to claim 1, wherein the transfer device is provided. 3. A terminal means for elastically pressing and contacting the electrode portion formed on the wide surface of the high voltage substrate is exposed on the back surface side of the transfer unit base, and is connected to the terminal means and the transfer member. The transfer device in the image forming apparatus according to claim 1, wherein the transfer device is connected to the wiring.