JPH06186862A - Image forming device - Google Patents

Abstract

PURPOSE:To easily and surely position a transfer guide plate and a transfer electrode provided in a clamshell type image forming device with respect to a photosensitive drum. CONSTITUTION:The photosensitive drum 3 held by a casing member 3A is attached to the upper main body 1 of the clamshell type image forming device in which the upper main body 1 is opened/closed to a lower main body 27. The transfer guide plate 23 is turnably supported by the supporting shaft 13A of a 2nd paper feeding lower roller 13a in the lower main body 27, and an electrode holder 25 by which the transfer electrode 7 and a separation electrode 8 are integrally held abuts on the reference surface 3B for an electrode holder of the casing member 3A and is positioned with respect to the drum 3 when the upper main body 1 is closed. Then, the transfer guide plate 23 descending along an interlocking plate 24 provided in the electrode holder 25 is positioned with respect to the drum 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer guide member and a transfer electrode positioning means provided in, for example, a copying machine of a clamshell type electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art Generally, an electrophotographic image forming apparatus having a structure in which a lower main body and an upper main body are divided into two, and the upper main body is rotated around a common support shaft to open and close with respect to the lower main body is a clamshell. It is called a type and is applied exclusively to the field of small popular machines.

In the upper body, for example, a document table and a document irradiation lamp which reciprocates below the document table, a scanning optical system composed of a reflection mirror and a fixed projection lens and a reflection mirror, and a predetermined potential by a band electrode. Is charged and rotated, a developing device for applying toner to the electrostatic latent image formed on the surface of the photosensitive drum by the scanning optical system to develop the photosensitive drum, and a photosensitive drum after transferring the toner image to recording paper. A cleaning device for cleaning the surface of the body drum is attached. On the other hand, on the lower main body, a recording paper conveying device that conveys the recording paper toward the lower side of the photosensitive drum surface when closed, a transfer electrode that transfers a toner image onto the recording paper surface, a separation electrode, and a transfer onto the recording paper surface It is equipped with a fixing device for fixing a toner image and a paper discharge roller, and is quite compact when closed.

Then, a required toner image is successively recorded on the surface of the recording paper which is intermittently conveyed along a predetermined conveying path.

Then, for example, the transfer material sent from the paper feed cassette loaded in the bottom of the image forming apparatus passes through a predetermined paper feed / conveyance system, and then is transferred to the photosensitive drum by a transfer guide member provided at a predetermined position on the lower main body side. The toner image formed on the photosensitive drum is transferred to the transfer material by the adjacent transfer electrodes that are guided.

[0006]

In order to obtain a good toner image, the transfer guide member that normally guides the transfer material toward the peripheral surface of the photosensitive drum has its guide surface and the leading end portion on the photosensitive drum and the adjacent transfer member. The transfer material must be accurately positioned in the conveying direction and the height direction with respect to the electrodes.
In particular, when the upper body mounting the photosensitive drum is opened and closed like a clamshell type image forming apparatus, a reliable positioning means for the transfer guide member and the transfer electrode with respect to the photosensitive drum is required. Conventionally, the position of the transfer guide member is manually adjusted by using a jig so that the transfer guide member can be mounted at a predetermined position with respect to the peripheral surface of the photoconductor drum. There are many variations, and it cannot be said that this is a reliable positioning means.

The present invention solves the above problems, and in particular, an image in which a transfer guide member provided in a clamshell type image forming apparatus can be easily and reliably positioned with respect to a photosensitive drum or a transfer electrode. An object is to provide a forming apparatus.

[0008]

[Means for Solving the Problems]
It is achieved by any one of b, c and d.

(A) A clamshell type image forming apparatus in which the upper body rotates around a common support shaft with respect to the lower body and is divided into two parts, the lower body and the upper body, to be opened and closed. In at least the upper body has an image carrier unit, and the lower body has a transfer electrode elastically supported by a movable transfer guide member for guiding a transfer material to a transfer position of the image carrier. And an image forming apparatus characterized in that the transfer guide member is positioned on the image carrier or the image carrier unit via the transfer electrode when the upper body is closed.

(B) A clamshell type image forming apparatus in which the upper body rotates about a common support shaft with respect to the lower body and is divided into two parts, the lower body and the upper body, to be opened and closed. In at least the upper body has an image carrier unit, and the lower body has a movable transfer guide member for guiding a transfer material to a transfer position of the image carrier and a transfer electrode. The image forming apparatus is characterized in that the transfer electrode is positioned on the image carrier or the image carrier unit via the transfer guide member when closed.

(C) A clamshell type image forming apparatus in which the upper body rotates about a common support shaft with respect to the lower body and is divided into two parts, the lower body and the upper body, to be opened and closed. In at least the upper body, an image carrier unit and a movable transfer guide member for guiding the transfer material to the transfer position of the image carrier are provided, and the lower body is supported so as to be vertically movable. An image forming apparatus having a transfer electrode that engages with a transfer guide member, wherein the transfer guide member is elastically supported with respect to a lower main body and positioned on an image carrier or an image carrier unit.

In (d) c, the image forming apparatus is characterized in that the transfer guide member is integrated with at least the transfer electrode.

[0013]

FIG. 1 is a first embodiment of the present invention.
1A is a side view showing the positioning means of the transfer guide member with respect to the image carrier, FIG. 1B is a side sectional view showing the structure of the stopper of the transfer guide plate, and FIG. 2 is the second embodiment. FIG. 4 is a side view showing the positioning means of the transfer electrode with respect to the image carrier, a side view showing the positioning means of the transfer guide member integrated with the transfer electrode with respect to the image carrier of the third embodiment, and the crumb of FIG. Configuration of shell-type image forming device (when closed)
Will be described with reference to a side cross-sectional view of FIG.

However, the present invention is not limited to this embodiment.

As shown in FIGS. 4 and 5, a clamshell type electrophotographic image forming apparatus 18 (hereinafter referred to as an image forming apparatus).
Is divided into two parts, a lower main body 27 and an upper main body 1 which is rotatably attached to the lower main body 27 via a common support shaft 28 to open and close. On the upper surface of the upper body 1, the original M
A platen glass P for installing the above is provided, and a scanning optical system 2 is provided below the platen glass P in the upper body 1. The scanning optical system 2 is a reciprocating document irradiation lamp 2.
a, the first mirror 2b, the second and third mirrors 2c forming a V shape, and the fixed lens 2d and the fourth mirror 2e. A photosensitive drum 3 is provided in the center of the inside of the upper body 1 so as to be rotatable in the direction of the arrow, and around the periphery thereof, a strip electrode 4 for uniformly charging the photosensitive body 3a along the rotation direction.
Further, the developing device 6 in which the toner is replenished by the toner replenishing device 5 and the developing sleeve 6b is built in, the charge eliminating electrode 9, and the cleaning device 10 are sequentially arranged.

A paper feed cassette 11 for storing recording paper is loaded in the space at the bottom of the lower main body 27 of the image forming apparatus 18, and the first paper feed for feeding the recording paper in the paper feed cassette 11 diagonally to the upper right. Paper feed by a paper roller 12, a guide plate 12a, a U-turn guide member 22 for making a U-turn of the recording paper upward in the direction of the photoconductor drum 3, and a pair of intermediate rollers 21 facing the conveyance path of the U-turn guide member 22. The U-turn part of the device is configured. Then, as shown in the figure, the bottom surface of the housing 6a of the developing device 6 (second cartridge 30) mounted on the upper main body 1 faces the guide surface of the flat portion of the U-turn guide member 22, and the upper transport guide surface. It is 6c. A second paper feed upper roller 13b is rotatably attached to the bottom surface of the developing device.

Then, 13a mounted on the lower main body 27 temporarily stops the recording paper fed by the intermediate roller pair 21 at the standby position, and then transfers the visible image front end on the photoconductor 3a and the recording paper front end to the transfer position. The second paper feed lower roller (the second paper feed upper roller 13b presses and rotates in a pair when closed) to feed the paper again toward the transfer position at an appropriate timing so as to match with each other. A transfer guide member for guiding the recording paper fed by the paper roller pair 13 to the transfer position of the photosensitive drum 3. 7 is a transfer electrode, 8 is a separation electrode,
Reference numeral 15 denotes a conveying device that conveys the recording sheet after transfer to the fixing position, and the fixing device 16 includes a heating roller 16a and a pressure roller 16b. Reference numeral 17 denotes a paper discharge roller that discharges the recording paper after fixing to the outside of the main body.

As shown in the figure, a first cartridge 20 containing the belt electrode 4, the photosensitive drum 3, and the cleaning device 10, a second cartridge in which the developing device 6 and the toner replenishing device 5 are unitized. Process cartridge which is divided into two parts such as 30 so that they can be separated from each other and combined.
40 is detachably attached to the upper main body 1 of the image forming apparatus 18. The first cartridge 20, the second cartridge 30, the paper feed / conveyance system and related process members have a length such that an image is recorded in the width direction of the B4 size recording paper (perpendicular to the paper surface). There is. When the image forming apparatus 18 is maintained or jammed, for example, the upper main body 1 rotated via the support shaft 28 is opened and held at a predetermined interval with respect to the lower main body 27.

When the copy button is operated while the above apparatus is closed, the original M on the platen glass P is exposed and scanned by the scanning optical system 2, and the electrostatic latent image of the original M on the photoconductor 3a of the photoconductor drum 3 is scanned. Is formed. This electrostatic latent image is made into a visible image by the developing device 6, and this visible image is fed to the paper feeding cassette 11
It is transferred by the transfer electrode 7 to the recording paper fed by making a U-turn from. After the transfer, the recording paper is separated from the photoconductor 3a by the separation electrode 8, is conveyed to the fixing device 16 by the conveying device 15, is fixed there, and is ejected by the ejection roller 17.
In this way, desired toner images are successively recorded on the recording paper surface.

Next, the means for positioning the transfer guide member 23 with respect to the photosensitive drum 3 according to the first embodiment of the present invention via the transfer electrode 7 will be described with reference to FIGS. 1 (a) and 1 (b).

Throughout the first, second, and third embodiments described below, members having the same function (including the members) have the same symbols even if their shapes are slightly different.

As shown in FIG. 1A, the transfer guide plate 23 provided on the lower main body 27 is a plate-like member formed in a substantially U shape, and its longitudinal direction (direction perpendicular to the paper surface) is, for example, that of a B4 size recording paper. It has a length capable of guiding the width direction toward the transfer position of the photosensitive drum 3. The upper surface of the U-shape shown in the figure is formed with a conveyance guide surface 23a for the recording paper, and the lower surface of the transfer guide plate 23 is engaged with an interlocking plate 24 rotatably provided on the transfer electrode 7 described later. An engagement surface 23b is formed. The right end portion of the transfer guide plate 23 is rotatably supported by the support shaft 13A of the second lower paper feed roller 13a.

As shown in the figure, the transfer electrode 7 and the separation electrode 8 are mutually positioned and held by the electrode holder 25 to form a unit. Semicircular projections 25a are provided at two predetermined heights on the left and right ends of the upper surface of the electrode holder 25 at positions not interfering with the conveyance of the recording paper. The upper surfaces of the projections 25a are, for example, photosensitive drums. So that the transfer electrode 7 and the separation electrode 8 are positioned with a predetermined distance from the peripheral surface of the photoconductor drum 3 by abutting against the electrode holder reference surface 3B provided on the casing member 3A for holding 3. Has become.

A boss 25b is planted on the lower surface of the electrode holder 25, and a boss 27b is also planted on the lower body frame 27A of the lower body 27 at a position facing the boss 25b.
An electrode holder pressing spring 36 whose upper end contacts the lower surface of the electrode holder 25 and whose lower end contacts the lower main body frame 27A surface is provided between b and 27b.

The electrode holder pressing spring 36 elastically biases the electrode holder 25 upward. Each boss 25
b, 27b and the electrode holder pressing spring 36 are provided at a plurality of positions (not shown) at appropriate intervals in the longitudinal direction of the electrode holder 25 (the direction perpendicular to the paper surface). An interlocking plate 24 is rotatably supported by a support shaft 33 on both side surfaces of the electrode holder 25 (only the front surface of the drawing is shown).
The interlocking plate 24 is urged to rotate in the counterclockwise direction by springs 32 that are respectively wound on the lower end faces 24a of the.

The spring 32 has an elastic force capable of sufficiently withstanding the weight of the transfer guide plate 23 and securely holding it. The interlocking plate 24 is a stopper (not shown) for the electrode holder 25 when the upper body 1 is opened.
Has stopped at a predetermined position by.

The bent surface of the tip portion 24b of the interlocking plate 24 abuts the lower surface of the engaging surface 23b of the transfer guide plate 23 so that the electrode holder
The transfer guide plate 23 is rotated up and down via the interlocking plate 24 with the upward and downward movement of 25. And FIG. 1 (b)
As shown in FIG. 5, the arm 25c is provided on the right side surface of the electrode holder 25 so as to project to the right, and the stopper 25d of the transfer guide plate 23 is provided on the lower surface of the tip of the arm 25c. The transfer guide plate 23, which is rotated upward by the interlocking plate 24, has its engaging surface 23b abutted against the stopper 25d, so that the leading end of the transfer guide plate 23a of the transfer guide plate 23 has the transfer electrode 7 Is positioned at a predetermined position with respect to.
Then, the electrode holder 25 and the transfer guide plate 23 are configured to move integrally via the interlocking plate 24.

The positioning operation of the transfer guide plate 23 thus constructed will be described.

The electrode holder provided on the casing member 3A for holding the photosensitive drum 3 when the opened upper main body 1 is lowered with the support shaft 28 as a fulcrum and is closed with respect to the lower main body 27 to reach the latter half of the closing time. Reference surface 3B is a protrusion of the electrode holder 25
The electrode holder 25 is pressed downward against the electrode holder pressing spring 36 by abutting on the upper surface of the electrode holder 25a. With the lowering of the electrode holder 25, the interlocking plate 24 also lowers, and the engaging surface 23b has the tip portion 24b.
The transfer guide plate 23, which is engaged with the bent surface, also rotates counterclockwise downward by its own weight around the support shaft 13A, and the transport guide surface 23a also descends. When the upper body 1 is closed at a predetermined position on the lower body 27, the transfer electrode 7 and the separation electrode 8 in the electrode holder 25 are positioned at a predetermined position with respect to the peripheral surface of the photosensitive drum 3. At the same time, the transport guide surface 23a of the transfer guide plate 23 is also reliably positioned at a predetermined distance from the peripheral surface of the photosensitive drum 3 via the interlocking plate 24 and the stopper 25d. Further, since the leading end portion of the transfer guide surface 23a of the transfer guide plate 23 is positioned at a predetermined position both vertically and horizontally with respect to the transfer electrode 7, even if the upper body 1 is vertically rotated, The position does not change. Therefore, variations in the transfer current distribution of the transfer electrode 7 are regulated, and the current distribution conditions are properly maintained, so that a good toner image can always be transferred onto the recording paper.

Then, when the upper main body 1 is opened, the pressing is released, and the transfer guide plate is moved as the electrode holder 25 and the interlocking plate 24 are raised.
23 also rotates upward, stops at a predetermined position, and waits.

Next, the means for positioning the transfer electrode 7 via the transfer guide plate 23 with respect to the photosensitive drum 3 of the second embodiment will be described.

As shown in FIG. 2, the transfer guide plate 23 provided in the lower main body 27 is a plate-like member formed in a substantially U shape, and its longitudinal direction (the direction perpendicular to the paper surface) is, for example, the width direction of B4 size recording paper. It has such a length that it can be guided toward the transfer position of the photosensitive drum 3. The upper surface of the U-shape shown in the figure is provided with a conveyance guide surface 23a for the recording paper, and a semicircular projection 23c as shown in the figure is provided on the upper surface of the tip of the conveyance guide surface 23a. A transfer guide plate reference surface 3D, which is formed in a semicircular concave surface with which the protrusion 23c abuts, is provided on a part of the casing member 3A of the photosensitive drum 3, and serves as a positioning surface for the transfer guide plate 23. There is. The transfer guide plate reference surface 3D is not limited to the concave shape and may be a flat projection. Therefore, in this case, the projection 23c at the tip of the transport guide surface 23a is not necessary and may be flat.

Below the transfer guide plate 23, there is provided a connecting portion 23d with the transfer electrode 7 as shown in the figure.
An arm 25c integrally provided at the right end portion of an electrode holder 25A holding the transfer electrode 7 is rotatably supported by a support shaft 33A at 23d.

The upper end of the transfer guide plate 23 is in contact with the bent portion provided at the upper end of the connecting portion 23d, and the lower end is the lower body 27.
The upper main body 1 is designed to rotate clockwise upward by a transfer guide plate pressing spring 35 that abuts against the frame 27A of
Stopper (not shown) provided on the lower body 27 when the
Is designed to stop at a predetermined position.
The right end portion of the transfer guide plate 23 is rotatably supported by the support shaft 13A of the second lower paper feed roller 13a as in the first embodiment.

A protrusion 25d shown in the figure is provided on the upper surface of both ends of the electrode holder 25A in the longitudinal direction, and the pin is attached to the support shaft 33A and has one end provided on the side surface of the electrode holder 25A.
The upper end of the projection 25d is brought into contact with the lower surface of the transport guide surface 23a by a predetermined pressing force by a spring 32 whose other end is applied to the connecting portion 23d of the transfer guide plate 23, so that the transfer guide plate 23 and the electrode holder 25A (including The transfer electrode 7) and the transfer electrode 7) are integrally rotatable.

Therefore, the electrode holder 25A also rotates vertically, following the transfer guide surface 23a of the transfer guide plate 23 that rotates vertically when the upper body 1 is opened and closed. The separation electrode 8 adjacent to the left side of the transfer electrode 7 has bosses 8b, 27b that are provided to face each other with one end abutting the lower surface of the separation electrode 8 and the other end abutting the lower body frame 27A of the lower body 27. It is pushed upward by the separated pole pressing spring 37 which is positioned. Each of the separation pole pressing spring 37 and each of the bosses 8b and 27b is provided at a plurality of positions with an appropriate interval in the longitudinal direction of the separation electrode 8. Then, the protrusions 8a provided at two positions on the left and right of the upper surface at both ends in the longitudinal direction of the case of the separation electrode 8 are brought into contact with the reference surface 3C for the separation electrode provided on the casing member 3A so that the peripheral surface of the photosensitive drum 3 and the predetermined surface are provided. It is arranged to be positioned at intervals. When the upper body 1 is opened, the separation electrode 8 is stopped at a predetermined position by a stopper (not shown) provided on the lower body 27 and stands by.

The positioning operation of the transfer electrode 7 thus constructed will be described.

When the opened upper main body 1 is lowered about the support shaft 28 as a fulcrum and is closed with respect to the lower main body 27 and the latter half of the closing time is reached, a reference for a transfer guide plate provided on the casing member 3A of the photosensitive drum 3 The surface 3D is the protrusion 23c of the transfer guide plate 23.
And the reference surface 3C for the separation electrode comes into contact with the protrusion 8a of the separation electrode 8 to push down the transfer guide plate 23 and the separation electrode 8 against the elasticity of the transfer guide plate pressing spring 35 and the separation electrode pressing spring 37. . Therefore, as the transfer guide plate 23 descends, the transfer electrode 7 integrated with the electrode holder 25A also descends.

When the upper body 1 is joined to the lower body 27 at a predetermined position, the transfer guide surface 23a of the transfer guide plate 23 is formed.
The transfer electrode 7 is positioned at a predetermined distance from the peripheral surface of the photosensitive drum 3, and at the same time, the transfer electrode 7 that descends due to the lowering of the transport guide surface 23a is also positioned at a predetermined position with the peripheral surface of the photosensitive drum 3. The transfer guide plate 23 is described as an example in which the transfer guide plate 23 is positioned in contact with the reference surface of the casing member 3A, but the present invention is not limited to this. For example, the transfer guide plate 23 may be contacted with the peripheral surface outside the image forming area of the photosensitive drum 3. . The transfer electrode 7 and the transfer guide plate 23, which are separate from each other, are positioned so that the leading end of the transport guide surface 23a is located at a predetermined position both vertically and horizontally with respect to the transfer electrode 7 as in the first embodiment. Since the upper body 1 is rotated to the upper body, the positions of the upper body 1 do not change.

Therefore, the variation of the transfer current distribution of the transfer electrode 7 is regulated and properly maintained under the predetermined current distribution condition, so that a good toner image is always transferred onto the recording paper. The transfer guide plate 23 is released when the upper body 1 is opened.
Rotate upward, and accordingly, the transfer electrode 7 is also pushed up, and at the same time, the separation electrode 8 is also pushed up and stopped at respective predetermined positions to stand by.

Next, the positioning means for the transfer guide plate 23 integral with the transfer electrode 7 of the third embodiment with respect to the photosensitive drum 3 will be described.

As shown in FIG. 3, the transfer guide plate 23 is, for example, a conveyance guide surface 23a for guiding a B4 size recording paper toward the transfer position of the photosensitive drum 3 and a right angle from the right end portion of the conveyance guide surface 23a. It is a plate-shaped member formed by the rising portion 23e that is raised, and the upper end of the rising portion 23e is rotatably supported by a support shaft 33B on a part of the casing member 3A of the photosensitive drum 3. . And transfer guide plate
23 has an upper end on the lower surface of the transport guide surface 23a and a lower end on the lower body.
It is pushed up by a transfer guide plate pressing spring 35 which is fitted and positioned on a boss 27b planted in a frame 27A of the lower main body of 27. Then, the leading end of the transport guide surface 23a comes into contact with the transfer guide plate reference surface 3E provided at both ends in the longitudinal direction of the casing member 3A so as not to interfere with the transport of the recording paper, thereby causing the photosensitive drum 3 to move. The peripheral surface and the transport guide surface 23a of the transfer guide plate 23 are positioned with a predetermined gap. Therefore, regardless of whether the upper main body 1 is opened or closed, the conveyance guide surface 23a and the peripheral surface of the photosensitive drum 3 are always rotated vertically with a predetermined gap. The transfer electrode 7 adjacent to the left side of the transfer guide plate 23 is raised to a predetermined height above the left end portion of the electrode case as shown in FIG.
A bent portion 7a having the same shape as the lower surface of a is provided, and is integrally connected to the lower surface of the transport guide surface 23a.
Therefore, the transfer electrode 7 and the transfer guide plate 23 are integrally rotated up and down when the upper body 1 is opened and closed. As shown in the drawing, the lower end of the transfer electrode 7 is positioned by being fitted to a boss 27b (common to the boss 27b for the transfer guide plate pressing spring 35) which is planted in the lower main body frame 27A of the lower main body 27. Since the upper end of the transfer electrode pressing spring 36 comes into contact with the transfer electrode 7 and pushes the transfer electrode 7 upward, the transfer guide plate 23
Comes into contact with the transfer guide plate reference surface 3E of the casing member 3A. Since the transfer electrode pressing spring 36 is provided, the transfer electrode 7 and the transfer guide plate 23 may be separated. In any case, since the leading end of the transport guide surface 23a is positioned both vertically and horizontally with respect to the transfer electrode 7, the positions of the upper body 1 are changed even if the upper body 1 is vertically rotated. do not do. Therefore, variations in the transfer current distribution of the transfer electrode 7 are regulated and properly maintained under the defined current distribution condition, so that a good toner image is always transferred onto the recording paper. The structure of the separation electrode 8 and the positioning means for the photoconductor drum 3 operate with the same functions as those of the second embodiment described above, and the description thereof will be omitted. Although not shown, the separation electrode 8 and the transfer electrode 7 may be integrally connected as in the first embodiment. The operation of the positioning means for the transfer guide plate 23 thus configured will be described.

When the opened upper main body 1 is lowered about the support shaft 28 as a fulcrum, the transfer guide plate 23 axially supported by the casing member 3A of the photosensitive drum 3 resists the elastic force of the transfer guide plate pressing spring 35. The transfer electrode 7 which is integrally coupled with the transfer electrode 7 also moves down against the transfer electrode pressing spring 36. When the final stage of closing the upper body 1 is reached, the ionization electrode 8 also descends against the separation electrode pressing spring 37 by the separation electrode reference surface 3C of the casing member 3A. When the upper body 1 is closed at a predetermined position with respect to the lower body 27, the transfer guide plate 23, the transfer electrode 7, and the separation electrode 8 are positioned at predetermined positions with respect to the photosensitive drum 3. Since the tip of the transport guide surface 23a and the transfer electrode 7 are positioned with respect to each other in the vertical and horizontal directions as described above, the transfer current distribution set as described above is maintained even if the upper body 1 rotates. Therefore, a good toner image can always be transferred onto the recording paper.

[0044]

By the positioning mechanism of the transfer guide member and the transfer electrode with respect to the photosensitive drum of the present invention, each can be positioned easily and surely. Further, since the transfer electrodes are integrally positioned or linked with the transfer guide plate so as to be positioned relative to each other, the positional relationship between the transfer electrodes does not change even when the upper body is opened and closed, and the transfer electrodes are always set. Since the current distribution condition is maintained, a good toner image is transferred onto the recording paper.

[Brief description of drawings]

FIG. 1A is a side view showing a positioning means of a transfer guide member with respect to an image carrier according to an embodiment of the present invention.
FIG. 6B is a side sectional view showing the structure of the stopper of the transfer guide member of the above.

FIG. 2 is a side view showing a positioning unit for positioning a transfer electrode with respect to an image carrier according to an embodiment of the present invention.

FIG. 3 is a side view showing a positioning means of a transfer guide member integrated with a transfer electrode with respect to an image carrier according to an embodiment of the present invention.

FIG. 4 is a side sectional view showing a configuration (when closed) of a clamshell type image forming apparatus.

FIG. 5 is a schematic diagram of the same as above when opened.

[Explanation of symbols]

 1 Upper Body 3 Photosensitive Drum 3A Casing Member 3B Reference Surface for Electrode Holder 3C Reference Surface for Separation Electrode 3D, 3E Reference Surface for Transfer Guide Plate 7 Transfer Electrode 8 Separation Electrode 13A Second Paper Feed Lower Roller Spindle 18 Image Forming Device 23 Transfer guide plate 23a Transport guide surface 23b Engaging surface 23c Protrusion 23d Connection 23e Start-up 24 Interlocking plate 25, 25A Electrode holder 25d Stopper 27 Lower body 27A Lower body frame 28 Spindle 35 Transfer guide plate pressure spring 36 Transfer Electrode pressure spring 37 Separated electrode pressure spring

Claims (4)

[Claims] 1. A clamshell type image forming apparatus in which an upper body is rotated around a common support shaft with respect to a lower body and is opened / closed by being divided into two parts, the lower body and the upper body. At least the upper body has an image carrier unit, and the lower body has a movable transfer guide member for guiding a transfer material to a transfer position of the image carrier, and a transfer electrode elastically supported. And an image forming apparatus characterized in that when the upper body is closed, the transfer guide member is positioned on the image carrier or the image carrier unit via the transfer electrode. 2. A clamshell type image forming apparatus in which an upper body is rotated around a common support shaft with respect to a lower body and is divided into two parts, the lower body and the upper body, to be opened and closed. At least the upper body has an image carrier unit, and the lower body has a movable transfer guide member for guiding a transfer material to a transfer position of the image carrier and a transfer electrode. An image forming apparatus characterized in that the transfer electrode is positioned on the image carrier or the image carrier unit via the transfer guide member when the transfer electrode is closed. 3. A clamshell type image forming apparatus in which an upper body rotates about a common support shaft with respect to a lower body and is divided into two parts, that is, the lower body and the upper body, to be opened and closed. , At least the upper body has an image carrier unit and a movable transfer guide member for guiding a transfer material to a transfer position of the image carrier, and the lower body is vertically movably supported to transfer the transfer material. A transfer electrode that engages with the guide member,
An image forming apparatus, wherein the transfer guide member is elastically supported with respect to a lower body and is positioned on an image carrier or an image carrier unit. 4. The image forming apparatus according to claim 3, wherein the transfer guide member is integrated with at least the transfer electrode.