JP2990302B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus for forming an image on a transfer material such as a copying machine or a printer. More specifically, the present invention relates to an image forming apparatus including an image carrier. And a detachable image forming apparatus.

[0002]

2. Description of the Related Art Many methods and apparatuses have been proposed for obtaining a color image using electrophotography. For example, JP-A-61
As disclosed in JP-A-100770, a latent image is formed and developed in accordance with the number of color separations of a document image on a photosensitive drum as an image forming body, and transferred to a transfer drum each time development is performed. There is a method of obtaining a color copy by forming a multicolor image thereon and then transferring it onto a transfer material. The device according to this method is:
In addition to the photosensitive drum, it is necessary to provide a transfer drum large enough to transfer one image on the peripheral surface thereof, and it is inevitable that the apparatus has a large and complicated structure.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-149972, a latent image is formed and developed on a photosensitive drum in accordance with the number of color separations of an original image. To obtain a multicolored color copy. In this method, it is difficult to accurately superimpose multi-color images, and a high-quality color copy cannot be obtained.

Further, a latent image is formed on the photosensitive drum in accordance with the number of separated colors of the original image and development with color toner is repeated, and a color image is obtained by superimposing and transferring the color toner image on the photosensitive drum. There is a way. The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-Open No. 60-75850 by the present applicant.
60-76766, 60-95456, 60-95458, 60-15847
No. 5 discloses this.

In a multicolor image forming apparatus which obtains a color image by such superposition, a plurality of developing devices containing color toners of different colors are arranged on the periphery of a photosensitive drum. Generally, the photosensitive drum is rotated a plurality of times to develop a latent image on the photosensitive drum to obtain a color image.

Such an image forming apparatus, particularly a color image forming apparatus, has a plurality of developing units and a plurality of toner replenishing devices corresponding to the plurality of developing units. Inspection of each material individually
It is extremely difficult to replace or supply.

For this reason, at least the photosensitive member and the cleaning member are integrated, or the photosensitive member, the developing device, the cleaning member and the like are housed in an integrated cartridge and mounted on the apparatus body in a unit state. A structure is adopted in which the cartridge can be removed from the apparatus main body by a simple operation.

[0008]

When such a cartridge type is adopted, the photosensitive member has a structure in which most of the photosensitive surface is shielded, but since the exposure area and the transfer area of the image are exposed, the inside of the apparatus is undesired. Dust and paper dust adhere even when the photoreceptor is mounted on the photoreceptor, and when the photoreceptor is detached from the apparatus, the photoreceptor surface may be further stained or damaged by touching hands or other objects.

The present invention has solved and improved this point,
It is an object of the present invention to provide an image forming apparatus that always protects a photosensitive surface by always exposing and exposing a transfer area of a photoreceptor except during an operation of an image forming process.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus having at least a detachable process cartridge having a built-in image carrier and a cleaning member in response to a power input to the apparatus or an image forming signal input. This is achieved by an image forming apparatus characterized in that at least a shielding member provided in an image transfer area of an image carrier is opened.

[0011]

FIG. 1 shows a first embodiment of an image forming apparatus according to the present invention.
5 to FIG.

In FIG. 1, reference numeral 1 denotes a flexible photosensitive belt serving as a belt-shaped image carrier. The photosensitive belt 1 is provided between rotating rollers 2 and 3 and is driven by the rotating roller 2. It is conveyed clockwise.

Reference numeral 4 denotes a support or guide member fixed so as to be in contact with the photoreceptor belt 1. The photoreceptor belt 1 is tensioned by the urging action of the rotating roller 3 to the outside. The inner peripheral surface is rubbed against the guide member 4.

Accordingly, the photosensitive member on the outer peripheral surface of the photosensitive belt 1 is always kept at a fixed relation to the surface of the guide member 4 even during the conveyance, so that a stable image forming surface can be formed. .

Reference numeral 6 denotes a scorotron charger as a charging means;
Denotes a laser writing unit as an image exposure means, and 8 to 11
Is a plurality of developing means or developing devices each containing a developer of a specific color, and these image forming means are disposed opposite to the outer peripheral surface of the photoreceptor belt 1 with the guide member 4 on the back side. Is done.

As the laser writing system unit 7, in addition to the optical system shown in the figure, an optical system or the like in which a light emitting unit and a converging light transmitter are integrated is used.

Each of the developing units 8, 9, 10, and 11 accommodates, for example, a developer of yellow, magenta, cyan, and black, respectively, and includes respective developing sleeves for maintaining a predetermined gap from the photosensitive belt 1. It has a function of visualizing a latent image on the photoreceptor belt 1 by a non-contact developing method. Unlike the contact development, the non-contact development has an advantage of not hindering the movement of the photosensitive belt.

Reference numeral 12 denotes a transfer unit, 12A denotes a charge removing bar, 13 denotes a cleaning unit or cleaning device, and a blade 13A of the cleaning device 13 and a toner conveying roller 13B are separated from the surface of the photosensitive belt 1 during image formation. It is pressed against the surface of the photoreceptor belt 1 as shown in FIG.

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

First, the formation of a multicolor image according to the present embodiment is performed according to the following image forming system. That is, data obtained by a color image data input unit in which an image sensor scans an original image is processed by an image data processing unit to create image data, which is temporarily stored in an image memory. Next, the image memory is taken out at the time of recording and inputted to a recording unit, for example, a 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 applied to the laser writing system unit 7.
In the laser writing system unit 7, the laser beam generated by the semiconductor laser (not shown) is rotationally scanned by a polygon mirror 7B rotated by a drive motor 7A, and is mirrored through an fθ lens 7C. The light path is bent by 7E and 7F, and projected on the peripheral surface of the photoreceptor belt 1 to which electric charges are previously applied by the charger 6 as a charging means, thereby forming a bright line.

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

That is, the photoreceptor belt 1 is charged again by the charger 6, and then the second color signal output from the signal processing unit is input to the writing unit 7, and the first color signal In the same manner as in the above case, writing is performed on the belt surface to form a latent image. The latent image is developed as a second color by a developing device 9 loaded with magenta (M) toner.

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

Reference numeral 10 denotes a developing device having cyan (C) toner, which forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing unit.

Further, reference numeral 11 denotes a developing device having a black toner, which forms a black toner image on the belt surface by the same processing. A DC or AC bias is applied to each sleeve of each of these developing units 8, 9, 10 and 11, and a jumping development is performed by a two-component developer as a visualizing means, and the photosensitive member whose substrate is grounded The belt 1 is developed in a non-contact manner. As the development, non-contact development using a one-component developer can also be used.

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

That is, one of the uppermost layers of the transfer material accommodated in the paper supply cassette 14 is carried out by the rotation of the paper supply roller 16, and the timing is synchronized with the image formation on the photosensitive belt 1 via the timing roller 17. It is supplied to the transfer device 12.

The transfer material that has undergone image transfer and charge removal is separated from the photoreceptor belt 1 that suddenly changes direction along the rotating roller 2 and is moved upward through an attraction type conveyance belt 17A. In the opposite direction, the image is welded by the fixing roller 18, and then discharged onto a tray formed on the upper lid 20 via the discharge roller 19.

On the other hand, the photoreceptor belt 1 after the transfer to the transfer material is further conveyed, and the remaining toner is removed by the cleaning device 13 in which the blade 13A serving as a cleaning member and the toner conveying roller 13B are pressed against each other. After the end, the blade 13A is separated again, and a little later, the toner transport roller 13B smoothes the toner accumulated on the tip of the blade 13A, and then the toner transport roller 13B
B is separated and a new image forming process is started.

The photoreceptor belt 1 is shown in FIG. 2 and FIG. 3 as a process material for image formation together with a charger 6 and respective developing devices arranged opposite to the lower peripheral edge and a cleaning device 13 arranged at the lateral end. It is incorporated in an independent color process cartridge 30 as shown, integrated therewith and detached from the apparatus main body. The color process cartridge 30 is not necessarily limited to the one in which all of the above-described process materials are incorporated, and at least the photosensitive belt 1 and the cleaning device
13 may be integrated.

The color process cartridge 30 further includes a developer supply section 30A on the side of the cleaning device 13 and a waste toner cartridge 30B integrated with the guide member 4.
The developer supply unit 30A has a function of supplying toner to each developing unit, and the waste toner cartridge 30B has a function of collecting waste toner removed by cleaning.

The color process cartridge 30 is inserted into and removed from the apparatus main body as follows.

That is, as shown in FIG. 5, which shows an AA cross section, a pedestal 50 which is slidably supported by engaging a leg 50A on the bottom surface with a pair of fixed guide rails 40 inside the apparatus.
Is provided, and the color process cartridge 30 is provided.
Is mounted on the gantry 50 and stored in the apparatus.

The rack 50 is integrated with a rack plate 51 which meshes with the pinion P1 of the motor M1 on the apparatus body side. The rack 50 is inclined and slid so as to form a dip when viewed from the upper right direction by the rotation of the motor M1. Is done.

The color process cartridge 30 has a set of guide members 31 in which arc-shaped slits are formed on the peripheral surface of the photosensitive belt 1 facing the image transfer area as shown in FIG.
Is installed.

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

The shielding member 32 is a flexible flat thin plate made of a spring metal plate, and a pair of string members 33A and 33B (each indicated by a dashed line) are provided at both ends thereof with the guide member. It is installed at a position where it can move in the slit formed by 31.

The other ends of the string members 33A and 33B are respectively connected to respective rotating shafts 34 provided in the color process cartridge 30.
Locked to A and 34B. The rotating shaft 34A is formed by coaxially integrating a gear G1 on the outer wall of the cartridge.
1 is connected via an intermediate gear IG1 to a motor m1 having an electromagnetic clutch (not shown) on the rotating shaft. On the other hand, the rotation shaft 34B is rotated by being biased clockwise by the torsion spring 35, and the string member 33B is wound a plurality of times to keep the shielding member 32 in a position where the image transfer area of the photosensitive belt 1 is closed. ing.

Further, the color process cartridge 30
A plate-shaped shielding member 36 is slidably housed in the inner surface of the opening 30C for exposure.

A string member (indicated by a dashed line) 37 is attached to one end of the shielding member 36 and fixed to one end of a rotating shaft 38 provided in the cartridge. A pair of tension springs 39 stretched between the outside and the process cartridge 30 are attached, and the tension springs 39
The biasing force keeps the shielding member 36 at the position where the opening 30C is closed.

The rotating shaft 38 is provided with a gear G on the outer wall of the cartridge.
And the gear G2 is an intermediate gear IG2
Is connected to a motor m2 having an electromagnetic clutch (not shown) on the rotating shaft.

For the motors m1 and m2, the power input, that is, the power switch provided in the operation unit of the apparatus is turned on, or the input of the image forming signal, that is, the power switch is turned on, and then the copy switch is operated. And at the same time, the electromagnetic clutches on the respective rotating shafts are also turned on, and the gear G1 is rotated clockwise to rotate the gear G
2 is rotated counterclockwise a predetermined number of times, and then stopped automatically.

As a result, each of the string members 33A and 37 is twisted by the bias of the torsion spring 35 or the tension spring 39 and wound around the rotation shaft 34A or 38, respectively, as shown in FIG. Numerals 36 move and retreat from the image transfer area of the photoreceptor belt 1 and the opening 30C for exposure, respectively, so that the laser writing system unit 7 can expose the original image and transfer the image to the transfer material. The motors m1 and m
Each of the electromagnetic clutches on the second rotating shaft is turned off by turning off the power switch or by turning off the signal by detecting the end of a series of operations by operating the copy switch to open the rotating shafts 34A and 38, respectively.

Accordingly, the respective shielding members 32 and 36 at the retracted positions including the second position shown in FIG. 4 are respectively wound around the rotating shafts 34B or 38 by the bias of the torsion spring 35 or the tension spring 39. Then, it returns to the position shown in FIG. 2 again and closes the image transfer area of the photoreceptor belt 1 and the opening 30C for exposure.

On the other hand, photo sensors S1, S2, S3, etc., which detect the passage of the transfer material, are provided at key points in the transfer material transport path. After the detection, if a sensor located on the downstream side cannot detect the transfer material even after a lapse of a predetermined time, a jam detection signal is output and the occurrence of the jam of the transfer material is detected. Each of the detected signals is input to the control unit of the apparatus main body,
It is output as a signal for controlling the rotation of the motor M1 and the motor M2 described later.

When the jam detection signal is input, the motor M1 starts to rotate in the reverse direction, and the color process cartridge 30
Is moved from the mounting position, that is, the first position where image formation is performed, to the second position shown in FIG.

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

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

That is, the upper lid 20 has, at its rotation base, a sector gear 21 which meshes with the pinion P2 of the motor M2 on the apparatus body side, and rotates counterclockwise from the position shown in the figure by the rotation of the motor M2. It is kept at a predetermined angle.

In this state, the color process cartridge 30
The above-mentioned shielding members 32 and 36 provided in the above are both placed in the shielding position, and operations such as removal of jammed paper and replenishment of toner are performed while the photosensitive belt 1 is protected.

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

When the reset button is depressed, the motor M1 rotates forward to move the color process cartridge 30 from the position shown in FIG. 4 to the direction shown in FIG. 1 again, and the light shielding plate 52 is detected by the photo sensor S4. Stop at the specified position.

In synchronization with this, the motor M2 also starts rotating forward and rotates the upper lid 20 clockwise to close the opening at the top of the apparatus body.

When the color process cartridge 30 is not mounted, that is, when the color process cartridge 30 is detached outside the apparatus, the shielding members 32 and 36 are maintained at the shielding position as in the case of the second position.

[0056]

According to the present invention, the photosensitive member is effectively prevented from adhering to dust and dirt, and its life is remarkably improved.
As a result, an image forming apparatus that can use the photosensitive member for a long period and can always record a high-quality image is provided.

[Brief description of the drawings]

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

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

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

FIG. 4 is a cross-sectional configuration diagram of a main part of the device.

FIG. 5 is a sectional view of a main part of the device.

[Description of Signs] 1 ... Photoreceptor belt 2,3 ... Rotating roller 12 ... Transfer unit 13 ... Cleaning device 17 ... Timing roller 30 ... Color process cartridge 30C ... Opening 31 ... Guide member 32,36 ... Shielding member 33A, 33B, 37: String member 34A, 34B, 38: Rotating shaft 35: Torsion spring 39: Extension spring M1, M2, m1,
m2: Motor G1, G2: Gear

Continuation of the front page (72) Inventor Tadayoshi Ikeda 2970 Ishikawacho, Hachioji-shi, Tokyo Examiner in Konica Co., Ltd. Examiner Hideki Suzuki (56) References JP-A-4-299360 (JP, A) JP-A-4- 283772 (JP, A) JP-A-2-27464 (JP, A) JP-A-62-201467 (JP, A) JP-A 62-193245 (JP, U) JP-A 60-199102 (JP, U) Hira 3-100856 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 21/14-21/18 G03G 21/00 370-540 G03G 15/00 550

Claims (3)

(57) [Claims] 1. An image forming apparatus comprising a detachable process cartridge containing at least an image carrier and a cleaning member, wherein at least image transfer of the image carrier is performed in response to a power supply input or an image formation signal input of the apparatus. An image forming apparatus, wherein a shielding member provided in an area is opened. 2. The process cartridge can be set to a first position for performing image formation and a second position for performing jam processing and toner replenishment / replacement. In the second position, the shielding member is in a closed state. The image forming apparatus according to claim 1, wherein 3. An image forming apparatus according to claim 1, wherein said shielding member is always kept closed when said process cartridge is not mounted on said apparatus.