JPH04328760A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the peripheral surface of a photosensitive belt by a shielding member owing to which there is no possibility that a process cartridge is inadvertently opened while it is handled on the outside of a device. CONSTITUTION:Shielding members 32 and 38 are movably provided at the respective aperture parts of the image transfer area and the exposing area of the photosensitive belt 1 incorporated in the process cartridge 30, and sliding plates 34 and 40 connected to the shielding members are locked at positions where the respective aperture parts are covered with the shielding members by the pressing of a twist spring 36 or a tension spring 41. In the case of loading the process cartridge 30 in the device, releasing plates 50A and 50B fixed in the device release the locking of the sliding plates 34 and 40, and further the shielding plates are moved by resisting the pressing of the spring to automatically retreat from the image transfer area and exposing area.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an electrophotographic image forming apparatus that forms images on transfer materials such as copying machines and printers, and more specifically, the present invention relates to an electrophotographic image forming apparatus that forms images on transfer materials such as copying machines and printers. The present invention relates to an image forming apparatus that can be attached and detached in the following state.

0002

2. Description of the Related Art Many methods and devices have been proposed for obtaining color images using electrophotography. For example, JP-A-6
As disclosed in Japanese Patent No. 1-100770, a latent image is formed and developed in accordance with the number of separated colors of the original image on a photosensitive drum serving as an image forming member, and is transferred onto a transfer drum each time the development is performed. There is a method in which a multicolor image is formed on a drum and then transferred onto a transfer material to obtain a color copy. In addition to the photoreceptor drum, the device using this method requires a transfer drum large enough to transfer one image onto its circumferential surface.
It is inevitable that the device will be large and have a complicated structure.

Furthermore, as disclosed in, for example, Japanese Patent Laid-Open No. 61-149972, a latent image is formed and developed on a photoreceptor drum according to the number of separated colors of an original image, and each time the development is performed, a latent image is formed on a transfer material. There is a method to obtain multicolor copies by transferring to With this method, it is difficult to overlap multicolor images with high precision, and it is impossible to obtain high-quality color copies.

[0004] Furthermore, formation of a latent image according to the number of separated colors of the original image on the photoreceptor drum and development with color toner are repeated, and the color toner images are superimposed on the photoreceptor drum and then transferred to obtain a color image. There is a way. The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-open No. 60-7585 by the present applicant.
No. 0, No. 60-76766, No. 60-95456,
This is disclosed in Japanese Patent No. 60-95458, Japanese Patent No. 60-158475, and the like.

[0005] In a multicolor image forming apparatus that obtains a color image by superimposing color images as described above, a plurality of developing units containing different color toners are arranged around the periphery of the photoreceptor drum. Generally, the photoreceptor drum is rotated multiple times to develop the latent image on the photoreceptor drum to obtain a color image.

[0006] Such image forming apparatuses, especially in the case of color image forming apparatuses, have a plurality of developing devices and a plurality of corresponding toner replenishing devices, so the structure of the image forming section becomes complicated, and the process Inspect each material individually,
Replacement or replenishment work is extremely difficult.

Therefore, at least the photoreceptor and the cleaning member are integrated, or the photoreceptor, the developing device, the cleaning member, etc. are housed in an integrated cartridge and installed in the main body of the apparatus as a unit, and then the photoreceptor, the developing device, the cleaning member, etc. A structure is adopted in which the cartridge can be removed from the main body of the apparatus by a simple operation.

[0008]

[Problems to be Solved by the Invention] When such a cartridge is formed, the photoreceptor has a structure in which most of the photosensitive surface is shielded, but since the image exposure area and transfer area are exposed, it is difficult to see outside the device. If the photosensitive surface is removed, dust may adhere to it and the photosensitive surface may be contaminated or damaged by touching it with hands or other objects.

[0009] As a result of solving this problem and improving the present invention,
The object of the present invention is to provide an image forming apparatus that protects the photosensitive surface by always shielding the exposure and transfer areas of the photosensitive member except when the image forming apparatus is installed in the apparatus.

0010

[Means for Solving the Problems] The above object is to provide an image forming apparatus that is removably equipped with a process cartridge that incorporates a belt-like photoreceptor and process means for forming each image provided on its peripheral portion. This is achieved by an image forming apparatus characterized in that a shielding member provided in an image transfer area and an image exposure area of the belt-shaped photoreceptor is opened by the mounting operation of the process cartridge.

[0011]

[Embodiment] FIG. 1 shows a first embodiment of the image forming apparatus of the present invention.
6 to 6.

In FIG. 1, reference numeral 1 denotes a flexible photoreceptor belt serving as a belt-like image carrier. Transported clockwise.

Reference numeral 4 denotes a support member or guide member fixed to be inscribed in the photoreceptor belt 1, and the photoreceptor belt 1 is brought into a tensioned state by the outward biasing action of the rotary roller 3. The guide member 4 rubs the inner peripheral surface thereof.

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt 1 are always maintained at a constant position relative to the surface of the guide member 4 even during conveyance, making it possible to form a stable image forming surface. .

6 is a scorotron charger as a charging means; 7
8 to 1 are laser writing system units serving as image exposure means;
Reference numeral 1 denotes a plurality of developing means, that is, developing devices, each containing a developer of a specific color, and each of these image forming means is arranged opposite to the outer circumferential surface of the photoreceptor belt 1 with the guide member 4 as its back surface. will be established.

In addition to the optical system shown in the drawings, the laser writing system unit 7 may also include an optical system that integrates a light emitting section and a convergent light transmission body.

Each of the developing devices 8, 9, 10, and 11 accommodates, for example, yellow, magenta, cyan, and black developers, respectively, and includes developing sleeves that maintain a predetermined gap from the photoreceptor belt 1. It has a function of making the latent image on the photoreceptor belt 1 visible by a non-contact development method. Unlike contact development, this non-contact development has the advantage of not interfering with the movement of the photoreceptor belt.

12 is a transfer device, 12A is a charge eliminating bar, and 13 is a cleaning section, that is, a cleaning device, which includes a blade 13A and a toner conveying roller 13.
B is maintained at a position apart from the surface of the photoreceptor belt 1 during image formation, and is pressed against the surface of the photoreceptor belt 1 as shown in the figure only during cleaning after image transfer.

The color image forming process by the color image forming apparatus is performed as follows.

First, the formation of a multicolor image according to this embodiment is performed according to the following image forming system. That is, data obtained by a color image data input section in which an image sensor scans an original image is subjected to arithmetic processing in an image data processing section to create image data, which is temporarily stored in an image memory. The image memory is then taken out during recording and input to a recording section, for example, the color image forming apparatus shown in the embodiment of FIG.

That is, the color signal output from the image reading device separate from the printer is transmitted to the laser writing system unit 7.
In the laser writing system unit 7, a laser beam generated by a semiconductor laser (not shown) is rotated and scanned by a polygon mirror 7B rotated by a drive motor 7A, passes through an fθ lens 7C, and then is transmitted to a mirror 7D and The photoreceptor belt 1 has its optical path bent by 7E and 7F and is charged in advance by a charger 6 serving as a charging means.
is projected onto the circumferential surface to form a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the first color signal is started, and the modulated beam scans the circumferential surface of the photoreceptor belt 1. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt 1 by main scanning by the laser beam and sub-scanning by the conveyance of the photoreceptor belt 1. This latent image is yellow (Y) in the developing means.
The toner (developing medium) is developed by the developing device 8 loaded with the toner (developing medium), and a toner image is formed on the belt surface. The obtained toner image, while being held on the belt surface, passes under a cleaning device 13, which is a cleaning means, which is separated from the peripheral surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photosensitive belt 1 is charged again by the charger 6, and then the second color signal outputted from the signal processing section is inputted to the writing system unit 7, and the above-mentioned first color signal Writing is performed on the belt surface in the same manner as in the case of , and a latent image is formed. The latent image is developed by a developer 9 loaded with magenta (M) toner as a second color.

This magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image.

A developing device 10 has cyan (C) toner, and forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing section.

Furthermore, numeral 11 is a developing device having black toner, which forms a black toner image superimposed on the belt surface by the same process. These developing devices 8, 9, 1
Direct current or even alternating current bias is applied to each sleeve 0 and 11, and jumping development is performed using a two-component developer, which is a developing means, and non-contact development is performed on the photoreceptor belt 1 whose base is grounded. It is about to be done. Note that as the development, non-contact development using a one-component developer can also be used.

The color toner image thus formed on the circumferential surface of the photoreceptor belt 1 is transferred to a transfer material fed from the paper feed cassette 14 via the paper feed guide 15 at the transfer section.

That is, the top layer of the transfer material stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and transferred to the photoreceptor belt 1 via the timing roller 17.
It is supplied to the transfer device 12 in synchronization with the above image formation.

The transfer material that has undergone image transfer and static electricity removal is reliably separated from the photoreceptor belt 1, which suddenly changes direction along the rotation roller 2, and is transported upward via the suction type conveyor belt 17A. After the image is fused by the fixing roller 18, the sheet is discharged via the discharge roller 19 onto a tray formed on the upper lid 20.

On the other hand, the photoreceptor belt 1, which has completed the transfer to the transfer material, continues to be conveyed, and the remaining toner is removed by the cleaning device 13 in which the blade 13A, which is a cleaning member, and the toner conveyance roller 13B are brought into pressure contact with each other. After waiting for the end of the process, the blade 13A is pulled away again, and a little later, the toner conveying roller 13B smoothes out the toner accumulated on the tip of the blade 13A.
The toner conveying roller 13B is separated and a new image forming process begins.

The photoreceptor belt 1 is shown in FIGS. 2 and 3 as a process material for image formation, together with a charger 6 and developing devices arranged opposite to each other on the lower periphery, and a cleaning device 13 arranged at the lateral end. It is incorporated into an independent color process cartridge 30 as shown, and is integrated and attached to and detached from the main body of the apparatus. The color process cartridge 30 is not necessarily limited to one that contains all of the process materials described above, and may be one in which at least the photoreceptor belt 1 and the cleaning device 13 are integrated.

The color process cartridge 30 further includes a developer replenishing section 30A on the side of the cleaning device 13.
Further, a waste toner cartridge 30B is built in integrally with the guide member 4, and the developer replenishing section 30A supplies toner to each developing device, while the waste toner cartridge 30B receives waste removed by cleaning. Each device has a function to collect toner.

The color process cartridge 30 is inserted into and removed from the main body of the apparatus in the following manner.

That is, as shown in FIG. 6 showing the AA cross section, inside the device, a pedestal 50 is provided which is slidably supported by engaging a pair of fixed guide rails 40 with legs 50A on the bottom surface. Then, the color process cartridge 30 is placed on the pedestal 50 and housed in the apparatus.

The pedestal 50 is integrated with a rack plate 51 that meshes with the pinion P1 of the motor M1 on the apparatus main body side, and is mounted by tilting and sliding so as to have an inclined angle when viewed diagonally from the upper right direction by the rotation of the motor M1. be done.

In the color process cartridge 30, a set of guide members 31 having arcuate slits as shown in FIG. 2 are installed on the circumferential surface of the photoreceptor belt 1 facing the image transfer area.

The guide members 31 are located on both sides of the photosensitive belt 1 outside the image area, and a shielding member 32 covering the image area is housed between them along the photosensitive surface.

The shielding member 32 is a highly flexible flat thin plate made of a springy metal plate, and a pair of string members 33A and 33B (each shown with a dashed line) is attached to each end of the guide member. It is attached at a position where it can move within the slit formed by 31.

The other end of the string member 33A is fixed to a column 34A of a sliding plate 34 that is slidably supported on the upper surface of the cartridge 30, while the other end of the string member 33B is installed inside the cartridge 30 and is twisted. It is locked onto a rotating shaft 35 which is always urged to rotate counterclockwise by a spring 36, and is further wound.

Therefore, when the process cartridge 30 is not placed in the mounting position, the sliding plate 34 is moved to the column 34A.
slides to the leftmost position where it contacts the outer wall of the cartridge 30, and engages with the protrusion 37A of the locking plate 37 with the shielding member 32 positioned in the image transfer area of the photoreceptor belt 1. It is fixed.

Further, the process cartridge 30 has a plate-shaped shielding member 38 slidably housed inside the exposure opening 30C.

A pair of string members 39 are attached to one end of the shielding member 38, and the string members 39 are attached to a sliding plate 4 slidably supported on the lower surface of the cartridge 30.
It is fixed to the column 40A of 0.

The other end of the shielding member 38 is secured to a pair of tension springs 41 which are stretched between the shielding member 38 and the process cartridge 30 in the exposure area.

Therefore, when the process cartridge 30 is not placed in the mounting position, the sliding plate 40
A has been slid to the furthest position where it contacts the outer wall of the cartridge 30, and the shielding member 38 is engaged with the protrusion 42A of the locking plate 42 in a position that closes the opening 30C. Fixed.

Furthermore, the process cartridge 30 has support plates H1, H2, H3 and It includes shielding plates C1, C2, C3 and C4 fixed to the tips of H4, respectively.

Each of the shielding plates is made of a soft and flexible synthetic resin plate such as Mylar, and each of the supporting plates is made of a thin plate having spring properties such as phosphor bronze or stainless steel, and the top of each shielding plate is photosensitive. The body belt 1 is attached and installed in a state in which it is in light pressure contact with the circumferential surface of the body belt 1.

In the process of installing the process cartridge 30 into the apparatus, the locking plates 37 and 42 first come into contact with release plates 50A and 50B fixedly installed within the apparatus.

Each of the locking plates is pressed and retracted inward of the cartridge 30 by contact with each release plate, and the sliding plate 3
4 and 40, each sliding plate is then brought into contact with each release plate and slides to the right, and when the cartridge 30 is installed in its storage position, it is in the position shown in FIG. reach

As a result, the shielding members 32 and 38 are moved and retracted from the image transfer area of the photoreceptor belt 1 and the opening 30C, respectively, against the torsion spring 36 or the tension spring 41, thereby preventing the process cartridge 30 from forming an image. Make it possible.

Furthermore, as shown in FIG. 4, each of the above-mentioned support plates H1,
H2, H3, and H4 are press pins D whose ends projecting from windows W on both sides of the cartridge project from both inner sides of the device.
1, D2, D3, and D4 and are pressed and elastically deformed, and the tops of the shielding plates C1, C2, C3, and C4 are separated from the circumferential surface of the photoreceptor belt 1, and the photoreceptor belt 1 is
transport circuit.

On the other hand, photosensors S1, S2, S3, etc. for detecting the passage of the transfer material are arranged at key points on the conveyance path of the transfer material, and the sensors located on the upstream side of each conveyance detect the passage of the transfer material. After the detection, if the downstream sensor cannot detect the transfer material even after a predetermined time has elapsed, a jam detection signal is output, and the occurrence of a jam in the transfer material is detected. Each of the detected signals mentioned above is input to the control section of the main body of the device,
It is output as a signal for controlling the rotation of the motor M1 and the motor M2, which will be described later.

When the jam detection signal is input, the motor M1 starts to rotate in reverse and rotates the color process cartridge 3.
0 is moved from the mounting position, that is, the first position where image formation is performed, to the second position as shown in FIG. 5, where jam removal or toner replenishment or replacement is performed.

The reverse rotation operation of the motor M1 is stopped when the light shielding plate 52 on the top surface of the cartridge is detected by the photosensor S5.

The upper lid 20 is rotatably supported by the apparatus main body via a shaft 20A, and is opened by rotating counterclockwise to open the opening at the upper part of the apparatus main body.

That is, the upper lid 20 has a sector gear 21 integrated in its rotating base that meshes with the pinion P2 of the motor M2 on the apparatus main body side, and is rotated counterclockwise from the illustrated position by the rotation of the motor M2. held at a given angle.

In this state, the color process cartridge 3
The above-mentioned shielding members 32 and 38 provided at 0 are both placed in the shielding position, and operations such as removing jammed paper and replenishing toner are performed while protecting the photoreceptor belt 1.

The process cartridge 30 is returned to the mounting position, that is, the first position, by operating a reset button provided on the operating section.

When the reset button is pressed, the motor M1 rotates in the forward direction to move the process cartridge 30 from the position shown in FIG. 5 to the position shown in FIG.
2 is stopped at the position detected by the photosensor S4.

[0059] In synchronization with this, the motor M2 also starts rotating in the forward direction, and the upper cover 20 is rotated clockwise to close the opening at the upper part of the main body of the apparatus.

Note that even when the process cartridge 30 is not installed, that is, when it is removed from the apparatus, the shielding members 32 and 38 are maintained at the closed position as in the case where the process cartridge 30 is at the second position.

[0061]

[Effects of the Invention] According to the present invention, the photoreceptor is effectively prevented from adhering to dust and dirt, and its lifespan is significantly improved.
As a result, an image forming apparatus that can use a photoreceptor for a long period of time and that can always record high-quality images has been provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus of the present invention.

FIG. 2 is a cross-sectional configuration diagram of a process cartridge of the apparatus.

FIG. 3 is a cross-sectional configuration diagram of a process cartridge of the apparatus.

FIG. 4 is a front view of the process cartridge.

FIG. 5 is a cross-sectional configuration diagram of main parts of the device.

FIG. 6 is a sectional view of essential parts of the device.

[Explanation of symbols]

1...Photoreceptor belt
2...Rotating roller 12...Transfer device
13...Cleaning device 17...Timing roller
30...Color process cartridge 30C...Opening part
31...Guide member 32, 38...Shielding member
33A, 33B, 39...String member 34, 40 sliding plate
35... Rotating shaft 36... Torsion spring
3
7, 42...Locking plate 41...Tension spring
50A, 50B...Release plate C1-C4...Shielding plate
H1~H4...Support plate

Claims (1)

[Claims] 1. An image forming apparatus removably equipped with a process cartridge containing a belt-shaped photoreceptor and process means for forming images provided on the peripheral edge thereof, wherein the process cartridge is attached to the apparatus by an operation of attaching the process cartridge to the apparatus. An image forming apparatus characterized in that a shielding member provided in an image transfer area and an image exposure area of a belt-shaped photoreceptor is in an open state.