JP2003241618A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device wherein a process cartridge which is defectively loaded to the device can be loaded to a prescribed position, dispensing with a special operation. <P>SOLUTION: The process cartridge is constituted so as to be pressurized and held while being pushed toward the positioning surface of the positioning part when the drum bearing of the process cartridge gets over the boundary position of the other end part of a spring 30 with reference to the positioning part of the device main body frame, and when a transfer belt unit for sucking and carrying the recording medium to respective process cartridges arranged in the vertical direction, the process cartridge is pushed by the transfer belt unit and the process cartridge is pushed into the inner side of the boundary position even in the case the process cartridge is placed on this side of the boundary position. <P>COPYRIGHT: (C)2003,JPO

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 copying machine or a printer.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a printer, a photosensitive drum as an image carrier on which a latent image is formed, and a charging means for uniformly charging the surface of the photosensitive drum, for example. A developing means for developing the latent image formed on the photosensitive drum by the exposing means, a cleaning means for removing the toner remaining on the photosensitive drum after transferring the toner image developed by the developing means onto a transfer material, and the like. A process cartridge (hereinafter abbreviated as cartridge) that is integrated and can be attached to and removed from the main body of the image forming apparatus.
The one with is proposed.

If this cartridge is not completely attached to the main body of the image forming apparatus, malfunction or image failure will occur, and various measures have been taken.

Japanese Patent Laid-Open No. 2000-98680 proposes a method of detecting the mounting state of the cartridge with high accuracy and notifying the user in the case of abnormality, but it is costly and the user has to redo the mounting work. Or, since it requires a reliable mounting operation, it is not desirable especially in an in-line color image forming apparatus having a plurality of cartridges.

Further, Japanese Patent Laid-Open No. 2001-232995 proposes a method in which a cartridge can be forcibly mounted in a predetermined position even if it is placed in front of a predetermined mounting position. Therefore, it is not suitable for an in-line color image forming apparatus having a plurality of cartridges.

Therefore, the present invention is intended to provide an image forming apparatus capable of providing a structure capable of reliably mounting a plurality of cartridges at low cost without complicating a user.

[0007]

A first invention has at least an image carrier on which an electrostatic latent image is formed and a developing means for developing the latent image on the image carrier, and the developing means develops the latent image. A process cartridge for transferring the formed toner image to a recording material at a transfer unit, a main body frame to which the process cartridge is detachably mounted, and an opening / closing body which is opened and closed with respect to the main body of the image forming apparatus when the process cartridge is attached and detached. In the image forming apparatus having the opening / closing body opened and detaching the process cartridge from the opening / closing body side with respect to the main body frame, the body frame presses the mounting portion of the process cartridge against the positioning portion. A pressing member for holding the pressing member, and the pressing member pushes the attached portion beyond the boundary position toward the positioning portion. Then, when the attached portion is abutted against the positioning surface of the positioning portion and elastically pressed and held, and the opening / closing body is closed with respect to the image forming apparatus main body, the opening / closing body is located on the front side of the boundary position. The process cartridge on which the attached portion is placed is pushed to push the attached portion to the back side beyond the boundary position.

A second aspect of the invention has at least an image carrier on which an electrostatic latent image is formed and a developing means for developing the latent image on the image carrier, and transfers the toner image developed by the developing means. A plurality of process cartridges of different colors to be transferred to a recording material by a unit, a plurality of the process cartridges arranged in the vertical direction, and a device main body frame that is detachably mounted, and an image formation when the process cartridge is attached and detached. An electrostatic transfer belt unit that is opened and closed with respect to the apparatus main body and that conveys the recording material to each of the transfer units, and holds the process cartridge with respect to the frame with the electrostatic transfer belt unit opened. In the image forming apparatus that is detached from the electrostatic transfer belt unit side, the process cartridges are attached to the frame. Each process cartridge has a pressing member that presses and holds the attached portion to the positioning portion, and when the attached portion is pushed toward the positioning portion beyond the boundary position, the pressing member causes the attached portion to When the electrostatic transfer belt unit is abutted against the positioning surface of the positioning unit and elastically pressed and held, and the electrostatic transfer belt unit is closed with respect to the image forming apparatus main body, the electrostatic transfer belt unit is located on the front side of the boundary position. It is characterized in that the process cartridge in which the mounting portion is placed is pushed to push the mounted portion beyond the boundary position and into the back side.

A third aspect of the present invention is the second aspect of the invention, wherein the electrostatic transfer belt unit is characterized in that the frame portion holding the electrostatic transfer belt abuts against the frame portion of the process cartridge and pushes it. .

In a fourth aspect based on the second or third aspect, the electrostatic transfer belt unit is constructed so as to be rotatable about a fulcrum on one end side in the vertical direction, and the electrostatic fulcrum from the rotational fulcrum. The distance to the opening / closing operation unit of the transfer belt unit is longer than the distance from the rotation fulcrum to the most distant process cartridge among all the process cartridges.

A fifth invention is characterized in that, in any one of the above inventions, the mounted portion of the process cartridge is a bearing member provided at both end portions of the image carrier.

According to a sixth aspect of the present invention, in any one of the above-mentioned aspects, the pressing member that presses and holds the mounted portion of the process cartridge against the positioning portion has the mounted portion directed toward the inner surface and the lower surface of the positioning portion. It is characterized by pressing with.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An image forming apparatus according to the present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a schematic sectional view of a color image forming apparatus according to an embodiment of the present invention.

[Overall Configuration] First, the overall configuration of the color image forming apparatus will be outlined with reference to FIG. In addition,
FIG. 1 is a vertical cross-sectional view showing the overall configuration of a full-color laser beam printer 100 which is one mode of a color image forming apparatus.

In FIG. 1, a color image forming apparatus 100 is provided.
Is provided with four photoconductor drums 1 (1a, 1b, 1c, 1d) as image holders arranged in the vertical direction.
The photosensitive drum 1 is rotationally driven counterclockwise by a driving unit (not shown). A charging device 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photoconductor drum 1 in order along the rotation direction of the photoconductor drum 1 and a photoconductor by irradiating a laser beam based on image information. The scanner unit 3 (3a, 3a, 3a for forming an electrostatic latent image on the drum 1)
b, 3c, 3d), developing devices 4 (4a, 4b, 4c, 4) for adhering toner to the electrostatic latent image and developing it as a toner image.
d), an electrostatic transfer device 5 that transfers the toner image on the photosensitive drum 1 to the transfer material S, and a cleaning device 6 (6) that removes the transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer.
a, 6b, 6c, 6d) and the like are provided. here,
The photosensitive drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are integrally formed into a cartridge to form a process cartridge 7.

The photosensitive drums 1 will be described in detail below.

The photosensitive drum 1 is constituted by coating an organic photoconductive layer (OPC photosensitive member) on the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Photoconductor drum 1
Both ends thereof are rotatably supported by support members, and are driven to rotate counterclockwise by transmitting a driving force from a drive motor (not shown) to one end.

As the charging device 2, a contact charging type device can be used. The charging member is a conductive roller formed in the shape of a roller. The roller is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the roller to make the surface of the photosensitive drum 1 uniform. It is to be charged.

The scanner unit 3 is arranged in a substantially horizontal direction of the photosensitive drum 1, and a polygon mirror 9 in which image light corresponding to an image signal is rotated at a high speed by a scanner motor (not shown) by a laser diode (not shown).
(9a, 9b, 9c, 9d) is irradiated. The image light reflected by the polygon mirror 9 forms the image forming lens 10 (10a,
10b, 10c, 10d), the surface of the charged photosensitive drum 1 is selectively exposed to form an electrostatic latent image.

Further, as shown in FIG. 5, the scanner unit 3 is formed longer than the pitch between the left and right side plates in the longitudinal direction, and is mounted so that the projection 33 projects from the opening hole 35 of the side plate 32 to the outside. The pressing method of the scanner unit at that time is about 4 as indicated by the arrow by the compression spring 36.
It is pressed downward by 5 ° with a force of about 1 kgf. As a result, it is reliably pressed against the abutting portion and positioned.

As shown in FIG. 2, the developing device 4 comprises a toner container 41 containing toners of respective colors of yellow, magenta, cyan and black, and the toner in the toner container 41 is supplied by a feeding mechanism 42. The toner is applied to the outer circumference of the developing roller 40, which is rotated clockwise in the figure, by the toner supply roller 43, which rotates in the clockwise direction in the figure, and the developing blade 44, which is pressed against the outer circumference of the developing roller 40. Is given.

By applying a developing bias to the developing roller 40 facing the photosensitive drum 1 on which the latent image is formed, toner development is performed on the photosensitive drum 1 according to the latent image.

An electrostatic transfer belt 11 is disposed so as to face all the photoconductor drums 1a, 1b, 1c, 1d arranged in the vertical direction and to circulate so as to come into contact with them. The electrostatic transfer belt 11 is composed of a film-like member having a volume resistivity of 10 ¹¹ to 10 ¹⁴ Ω · cm and a thickness of about 150 μm. The electrostatic transfer belt 11 is supported by rollers with four axes in the vertical direction, and circulates so that the transfer material S is electrostatically adsorbed on the outer peripheral surface on the left side of the drawing to bring the transfer material S into contact with the photosensitive drum 1. To do. As a result, the transfer material S becomes the electrostatic transfer belt 1
The toner image on the photosensitive drum 1 is transferred to each transfer position by 1.

Abutting on the inside of the electrostatic transfer belt 11,
The transfer roller 12 (12a, 12b, 12c, 12) is provided at a position facing the four photoconductor drums 1a, 1b, 1c, 1d.
d) are installed side by side. A positive charge is applied from the transfer roller 12 to the transfer material S via the electrostatic transfer belt 11, and an electric field generated by the charge causes the transfer material S in contact with the photosensitive material drum 1 to be transferred onto the photosensitive material drum 1. A negative toner image is transferred.

The electrostatic transfer belt 11 has a circumference of about 700 mm,
The belt has a thickness of 150 μm and is wound around four rollers of a driving roller 13, driven rollers 14a and 14b, and a tension roller 15, and rotates in the direction of the arrow in the figure. Accordingly, the toner image is transferred while the above-described electrostatic transfer belt 11 circulates and the transfer material S is conveyed upward from the driven roller 14a side to the drive roller 13 side.

The paper feed unit 16 feeds and conveys the transfer material S to the image forming unit, and a plurality of transfer materials S are stored in the paper feed cassette 17. Paper feed roller 1 during image formation
8 (half-moon roller), the pair of registration rollers 19 are driven to rotate in accordance with the image forming operation, and the transfer material S in the paper feed cassette 17 is transferred.
While the sheet is separated and fed one by one, the leading end of the transfer material S abuts against the registration roller pair 19 and temporarily stops, and after forming a loop, the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized, and the registration roller pair is synchronized. Paper is fed to the electrostatic transfer belt 11 by 19.

The fixing section 20 is for fixing the toner images of a plurality of colors transferred onto the transfer material S, and includes a rotating heating roller 21a and a pressurizing member which is in pressure contact with the heating roller 21a to apply heat and pressure to the transfer material S. And a roller 21b.

That is, the transfer material S on which the toner image on the photosensitive drum 1 is transferred is conveyed by the fixing roller pair 21 composed of the heating roller 21a and the pressure roller 21b when passing through the fixing section 20, and at the same time, Heat and pressure are applied by the fixing roller pair 21. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.

In the image forming operation, the process cartridges 7a, 7b, 7c and 7d are sequentially driven in accordance with the print timing, and the photosensitive drum 1 is driven in accordance with the driving.
a, 1b, 1c, and 1d are rotationally driven counterclockwise. Then, the scanner unit 3 corresponding to each process cartridge 7 is sequentially driven. By this driving, the charging roller 2 applies a uniform electric charge to the peripheral surface of the photoconductor drum 1, and the scanner unit 3 moves to the photoconductor drum 1 thereof.
The peripheral surface is exposed according to an image signal to form an electrostatic latent image on the peripheral surface of the photosensitive drum 1. The developing roller 40 in the developing device 4 transfers toner to the low potential portion of the electrostatic latent image to form (develop) a toner image on the peripheral surface of the photosensitive drum 1.

The most upstream photosensitive drum 1 in the transfer material conveying direction
At the timing when the front end of the toner image formed on the peripheral surface of (1a) is rotationally conveyed to the point where it opposes the electrostatic transfer belt 11, the print start position of the transfer material S coincides with that point. The registration roller pair 19 starts rotating to feed the transfer material S to the electrostatic transfer belt 11.

The transfer material S is pressed against the outer circumference of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic transfer roller 22 and the electrostatic transfer belt 11, and between the electrostatic transfer belt 11 and the electrostatic transfer roller 22. A voltage is applied to the transfer material S, which is a dielectric, to induce an electric charge in the dielectric layer of the electrostatic transfer belt 11, and the transfer material is electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. ing. As a result, the transfer material S
Is stably attracted to the electrostatic transfer belt 11 and is conveyed to the most downstream transfer unit.

While being conveyed in this way, the transfer material S sequentially transfers the toner images on the respective photosensitive drums 1 by the electric field formed between the respective photosensitive drums 1 and the transfer roller 12. The transfer material S to which the toner images of four colors have been transferred is curvature-separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13, and is carried into the fixing unit 20. The transfer material S is heat-fixed with the toner image by the fixing unit 20, and then is discharged from the main body by the paper discharging roller pair 23 from the paper discharging unit 24 with the image surface facing down.

The process cartridge will be described in detail with reference to FIGS. 2 and 3 show a main cross section and a perspective view of the process cartridge 7 containing the toner. The yellow, magenta, cyan, and black process cartridges 7a, 7b, 7c, and 7d have the same configuration.

The process cartridge 7 is a drum-shaped electrophotographic photosensitive member which is an image bearing member, that is, the photosensitive drum 1.
A photosensitive drum unit 50 having a charging unit and a cleaning unit, and a developing unit 4 having a developing unit for developing the electrostatic latent image on the photosensitive drum 1.

The photosensitive drum unit 50 is rotatably attached to the cleaning frame 51 via the bearing 31 (31a, 31b) which is a bearing of the photosensitive drum 1. On the circumference of the photosensitive drum 1, the photosensitive drum 1
Primary charging means 2 for uniformly charging the surface of the photosensitive drum 1 and a cleaning blade 60 for removing the developer (toner) remaining on the photosensitive drum are arranged, and the surface of the photosensitive drum 1 is further cleaned by the cleaning blade 60. The residual toner removed from the toner feeding mechanism 52 is sequentially fed to a waste toner chamber 53 provided at the rear of the cleaning frame.

Then, the driving force of a drive motor (not shown) is transmitted to an input portion provided at one end on the rear side in the figure, so that the photosensitive drum 1 is rotated counterclockwise in the figure in accordance with the image forming operation. I am trying to let you.

On the other hand, the developing unit 4 includes the photosensitive drum 1
A developing roller 40 that contacts with the developing roller 40 and rotates in the direction of the arrow Y, a toner container 41 containing toner, and a developing frame 45. Both ends of the developing roller 40 are rotatably supported by a developing device frame 45 via bearing members, and toner is supplied on the periphery of the developing roller 40 in contact with the developing roller 40 and rotating in the arrow Z direction. A roller 43 and a developing breaker 44 are arranged respectively. Further, inside the toner container 41, a toner conveying mechanism 42 for stirring the contained toner and conveying it to the toner supply roller 43 is provided.

The developing unit 4 is the developing unit 4
Centering around hollow support shafts 49 provided on bearing members 47 and 48 attached to both ends of the developing unit 4, the entire developing unit 4 is supported with respect to the photosensitive drum unit 50 by a pin 49a pivotally supported in the supporting shaft 49. The suspension structure is swingably supported so that the developing roller 40 contacts the photosensitive drum 1 by a rotation moment about the support shaft 49 when the process cartridge 7 is alone (not mounted on the printer body). , Photosensitive drum unit 50
Between the developing unit 4 and the developing unit 4, the developing unit 4 is constantly urged by the pressure spring 53 arranged on the opposite side of the photosensitive drum 1 with the support shaft 49 interposed therebetween.

Next, a mechanism for mounting the process cartridge 7 in the printer body 100 will be described with reference to FIG. In FIG. 4, the photosensitive drum 1 and the bearing 31 (31
Although only a, 31b) are shown, in the color printer of the present embodiment, the process cartridge 7 (FIG. 2) in which the charging unit 2, the developing unit 4, and the cleaning unit 6 are integrally configured as described in the overall configuration. ).

Printer body 1 of process cartridge 7
The mounting of 00 on the frame F is performed by inserting a bearing 31 for supporting the photosensitive drum 1 along the first guide groove 34 from the direction of the arrow as shown in FIG.

In this frame F, groove portions 34a to 34d, 34e are provided at the front corners of the left and right side plates 32 in upper and lower four stages, respectively.
To 34h are formed so as to face each other at the same level, and between 34a and 34e, between 34b and 34f, and between 34c and 34 that face each other.
Bearings 31a and 31b attached to the left and right shaft ends of the photosensitive drum 1 are inserted between g and between 34d and 34h.

Then, as shown in FIG. 6, the position of the process cartridge 7 is determined by pressing the bearing 31 against the lower surface of the groove portion 34 which is the positioning portion of the main body and the abutting surfaces 37 and 38 which are the inner surfaces.

Regarding the method of pressing the process cartridge 7 in the printer main body, as shown in FIG. 5, the left and right side plates 32 are respectively caulked with shafts 39, and the shaft 39 supports a torsion coil spring 30. One end 3
0a is fitted and fixed in holes 32a formed in the left and right side plates 32. The other end of the torsion coil spring 30 extends toward the front side of the apparatus body and is bent at about 90 degrees so as to face the groove 34, and the tip of this bent portion is located outside the groove 34. It opens so that it comes into contact with the bearing 31 when the process cartridge 7 is mounted.

In the state where the process cartridge 7 is not provided, the torsion coil spring 30 is regulated in the rotation direction by the other end of the torsion coil spring 30 coming into contact with the protrusion 32b formed by bending and raising from the left and right side plates 32. Has been done.

When the process cartridge 7 is inserted, the bearing 31 pushes up the tip of the bent portion at the other end of the torsion coil spring 30 as described above, and the other end of the torsion coil spring 30 moves counterclockwise. The other end of the spring 30 is rotated when it is rotated against the force and the process cartridge 7 is inserted deeper than the boundary position, that is, when the bearing 31 goes over the corner of the bent portion of the other end of the spring 30. The spring 30 rotates clockwise by the restoring force of the spring, the other end of the torsion coil spring 30 pushes the bearing 30, and the bearing 30 is further retracted to the abutting surfaces 37, 38 for positioning as shown in FIGS. It hits against and is pressed with a force of about 1 kgf in the direction of the arrow. Normally, the user inserts the process cartridge 7 of each color to a predetermined position and the mounting is completed. At that time, the user can confirm that the process cartridge 7 is securely attached because of the click feeling.

However, there is a possibility that the process cartridge 7 is placed in front of the boundary position where it is pulled inward by the torsion coil spring 30, that is, it is imperfectly mounted.

FIG. 7 shows a state in which all the process cartridges 7 are incompletely mounted. The electrostatic transfer belt unit rotates about a rotation fulcrum 11a provided at the lower part, and the process cartridge 7 is detached by opening the electrostatic transfer belt unit 11 as shown in FIG. When the electrostatic transfer belt unit 11 is closed, first, the casing 11c of the transfer belt unit 11 comes into contact with the casing 8a of the process cartridge 7a located at the bottom, and the casing 8c of FIG.
Start pushing it in, as shown in. When the transfer belt unit 11 is further closed and the process cartridge 7a is pushed farther from the boundary position as shown in FIG. 8B, the bending of the other end of the torsion coil spring 30 causes the process cartridge 7a to operate as described above. 7a is retracted to the back side, abutted against the abutting surfaces 37, 38, and fixed, and positioned at a predetermined position. If the transfer belt unit 11 is further closed, the above operation is repeated from the lower side of the process cartridge 7, that is, in the order of 8b, 8c, and 8d, and the transfer belt unit 11 is positioned on the positioning surface 12 as shown in FIG. When it is closed until it hits, all process cartridges 7 are fully installed,
Casing 11c of electrostatic transfer belt unit 11 and casings 8a, 8b, 8 of all process cartridges
It is separated from c and 8d. That is, all process cartridges 7 are correctly mounted for each color, and the state is the same as when the electrostatic transfer belt is finally closed.

By pressing the process cartridge 7 by the transfer belt unit 11 by bringing the respective casings into contact with each other, it is possible to protect the components related to printing, and also to provide the force for the user to operate the transfer belt unit 11. , Can be reliably transmitted to the process cartridge 7.

The opening / closing operation of the transfer belt unit 11 is a rotary type, and the process cartridge 7 is moved from the fulcrum 11a.
By distributing the distances up to, the timing of pushing the casing 8 of the process cartridge of each color when closing the transfer belt unit 11 is 8a, 8b, 8c, 8d.
It becomes easy to shift in the order of, and the operation force for the user to close the transfer belt unit 11 can be reduced.

Further, the user selects the transfer belt unit 11
In addition to the handle 11b serving as the operating portion, a handle 11b for opening and closing is provided on the uppermost portion, and the distance from the rotation fulcrum 11a to the operating portion 11b is longer than the distance from the fulcrum 11a to all process cartridges 7. The applied operation force can be efficiently converted into a moment, and the process cartridge 7 can be pushed in with a force smaller than the reaction force when the process cartridge 7 is directly pushed in. Therefore, the operation force for closing the electrostatic transfer belt unit can be reduced.

[0052]

As described above, according to the present invention,
The process cartridge can be fixed at a predetermined positioning position with a simple configuration, and at the same time, even when the user mounts the process cartridge in an incomplete position,
By closing the transfer belt unit with respect to the main body of the image forming apparatus, it becomes possible to mount all process cartridges at predetermined positions. Therefore, it is possible to provide an in-line color image forming apparatus that does not cause a malfunction or an image defect due to incomplete mounting at low cost without compelling the user to perform a complicated operation.

[Brief description of drawings]

FIG. 1 is a sectional view showing a color image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the process cartridge of FIG.

FIG. 3 is an exploded perspective view of the process cartridge of FIG.

FIG. 4 is a perspective view showing a frame structure of an image forming apparatus in which the process cartridge of FIG. 1 is mounted.

5 is a side view showing a part of the frame of FIG.

FIG. 6 is a diagram showing a part of FIG. 5;

7 is a cross-sectional view of a state in which a process cartridge is incompletely attached to the image forming apparatus of FIG.

8A and 8B are cross-sectional views showing a process of mounting the process cartridge in the color image forming apparatus by moving the transfer belt unit in the closing direction in the state of FIG.

9 is a cross-sectional view showing the complete mounting of the process cartridge in the color image forming apparatus through the mounting process of FIG.

[Explanation of symbols]

1 (1a-1d) photoconductor drum 2 (2a-2d) Charging device 3 (3a-3d) Scanner unit 4 (4a-4d) Developing device, developing unit 5 Electrostatic transfer unit 6 (6a-6d) Cleaning device 7 (7a-7d) process cartridge 8 (8a-8d) Process cartridge casing 11 Electrostatic transfer belt 12 Positioning abutting surface of electrostatic transfer belt 20 Fixing unit 31 (31a, 31b) Bearing 34 (34a to 34h), guide groove 37 Bearing left / right positioning abutting surface 38 Positioning abutment surface of bearing in vertical direction 40 (40a-40d) Developing roller 46 (46a-46d) ribs 47/48 Bearing member 49 Support shaft 49a pin 50 Photosensitive drum unit 53 Pressure spring

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H071 AA03 BA04 BA13 BA14 BA16                       BA29 DA08 DA09                 2H200 FA12 GA16 GA23 GA34 GA47                       HA02 HB12 JB06 JB25 JB46                       LA03 MB04

Claims (6)

[Claims] 1. A recording material having at least an image carrier on which an electrostatic latent image is formed and a developing means for developing the latent image on the image carrier, and a toner image developed by the developing means at a transfer portion. A process cartridge for transferring to, and a body frame to which the process cartridge is detachably mounted,
An image forming apparatus that has an opening / closing body that is opened and closed with respect to an image forming apparatus main body when the process cartridge is attached and detached, and that attaches and detaches the process cartridge to and from the main body frame from the opening and closing body side with the opening and closing body open. In the main body frame, a pressing member for pressingly holding the mounted portion of the process cartridge at a positioning portion,
When the attached portion is pushed toward the positioning portion beyond the boundary position, the pressing member abuts the attached portion against the positioning surface of the positioning portion to elastically press and hold the opening / closing body. Is closed with respect to the main body of the image forming apparatus, the opening / closing body pushes the process cartridge in which the attached portion is placed on the front side of the boundary position and pushes the attached portion beyond the boundary position to the rear side. An image forming apparatus characterized by being pushed into. 2. A recording material having at least an image bearing member on which an electrostatic latent image is formed and a developing unit for developing the latent image on the image bearing member, and a toner image developed by the developing unit at a transfer unit. A plurality of process cartridges of different colors to be transferred to, a plurality of process cartridges arranged in a vertical direction, and an apparatus main body frame that is detachably mounted, and an image forming apparatus main body when the process cartridge is attached and detached. And an electrostatic transfer belt unit that conveys the recording material to each of the transfer units,
In the image forming apparatus, wherein the process cartridge is detached from the electrostatic transfer belt unit side with respect to the frame with the electrostatic transfer belt unit opened, a mounting portion of each process cartridge is attached to the frame as a positioning portion. Each of the process cartridges has a pressing member that presses and holds the attached portion of the positioning portion when the attached portion is pushed toward the positioning portion beyond the boundary position. When the electrostatic transfer belt unit is abutted against the positioning surface and elastically pressed and held, and the electrostatic transfer belt unit is closed with respect to the image forming apparatus main body, the electrostatic transfer belt unit has the attached portion on the front side of the boundary position. Push the process cartridge that has been placed to push the attached part to the back side beyond the boundary position. An image forming apparatus characterized by being embedded. 3. The image forming apparatus according to claim 2, wherein in the electrostatic transfer belt unit, a frame portion holding the electrostatic transfer belt abuts and pushes a frame portion of the process cartridge. 4. The electrostatic transfer belt unit is configured to be rotatable about a fulcrum on one end side in the vertical direction, and a distance from the rotation fulcrum to an opening / closing operation portion of the electrostatic transfer belt unit is the rotational position. The image forming apparatus according to claim 2, wherein the distance from the fulcrum to the most distant process cartridge among all the process cartridges is longer. 5. The image forming apparatus according to claim 1, wherein the attached portion of the process cartridge is a bearing member provided at both ends of the image carrier. 6. The pressing member, which presses and holds the mounted portion of the process cartridge against a positioning portion, presses the mounted portion toward the inner surface and the lower surface of the positioning portion. The image forming apparatus according to any one of 1 to 5.