JPH03266857A - Color image forming device - Google Patents

Abstract

PURPOSE:To make an image forming unit compact and to extremely facilitate maintenance by integrally forming an image forming body and a transfer body, etc., thereby constituting a process unit. CONSTITUTION:A photosensitive belt 1 is laid and stretched between turning rollers 2 and 3 and driven by making its inner peripheral surface slide on a guiding member 4. A transfer device 14 and a separation device 16, etc., are provided in a transfer drum 12 and the photosensitive belt 1, the transfer drum 12, and a laser write unit 7, etc., are integrally housed in a cartridge 30. Therefore, the image forming body is attached to/detached from a device main body without impairing positional accuracy and the image forming unit is made compact. By turning the cartridge 30 upward centering around a specified supporting point, a developing unit 40, etc., is lifted and cleaning and exchange are easily performed when jamming occurs.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to color electrophotographic copying machines, color printers, etc. that synthesize color images on a transfer material using a rotating transfer body wrapped around a transfer material. The present invention relates to an image forming apparatus.

[Conventional technology]

As a color image forming apparatus, for example, Japanese Patent Application Laid-Open No. 60/767
According to Publication No. 66, a color toner image is formed on an image forming body by repeatedly writing image data for each color using a laser beam scanner and developing with a developer containing color toner, and this is transferred to a transfer material by corona radiation. There is known an apparatus that performs electrostatic batch transfer using an electric device, and then fixes the transfer material to record a color image. This device superimposes toner images of each color on the image forming body, so it has advantages such as excellent superimposition accuracy. There are also problems such as the inability to obtain good color images with conventional analog systems.

Therefore, for example, Japanese Patent Application Laid-open No. 123257/1983 proposes a technique in which toner images of each color are superimposed on a transfer material using a rotating transfer body around which a transfer material is wound. This technology involves writing on an image forming body with a laser beam modulated by a digital signal of separated color image information, development with a developer containing color toner, and wrapping the color toner image obtained by the development around the transfer body. By repeating the transfer to a transfer material, a color toner image is formed on the transfer material, and this is fixed to record a color image. That is, the process is the same as the monochrome image forming process in that each time a toner image is formed on an image forming body, it is transferred to a transfer material.

Regarding image forming bodies, there have been proposed photosensitive drums in which a photoconductor is coated or vapor deposited on the circumferential surface of the drum, as well as belt-shaped image forming bodies in which a photoconductor is coated or mounted on a flexible belt. The shape of the belt-shaped image forming body (hereinafter also referred to as a photoconductor belt) is determined by stretching it between rotating rollers including a drive roller, so it is possible to effectively utilize space and create a compact color image forming apparatus. It is effective when configured.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a transfer type color image forming apparatus that is compact and has excellent characteristics, particularly in terms of maintainability.

[Structure of the invention]

The above object is to provide a color image having a plurality of developing devices upstream in the moving direction of a belt-like image forming body that is stretched between a plurality of rotating rollers and a transfer body adjacent to the rotating rollers downstream. This is achieved by a color image forming apparatus characterized in that the belt-like image forming body and the transfer body constitute an integrally formed process unit that can be inserted and removed.

Note that the belt-like image forming body is preferably used in a horizontally stretched manner.

〔Example〕

One embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

In FIG. 1, l is a flexible photoreceptor belt which is a belt-like image forming member, and the photoreceptor belt l is a rotating roller 2 and 3.
The material is conveyed clockwise by the drive of a rotating roller 2, which is constructed of a rubber roller and is installed between the materials.

Reference numeral 4 denotes a guide member inscribed in the photoreceptor belt 1. The photoreceptor belt 1 is kept under tension by the upward bias of the tension roller 5, and its inner peripheral surface is rubbed against the guide member 4.

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt l are always maintained at a constant relative position with respect to the surface of the guide member 4 even during conveyance, and a stable image forming surface can be constructed.

6 is a scorotron charger as a charging means; 7 is a laser writing system unit; and 8 to 11 are a plurality of developing units each containing a developer of a specific color. The photoreceptor belt 1 is disposed opposite to the outer circumferential surface of the photoreceptor belt l.

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 such as an LED and a convergent light transmission body.

Each of the developing units 8 to 11 accommodates, for example, yellow magenta, cyan, and black developers, respectively, and each developing sleeve 8 maintains a predetermined gap with the photoreceptor belt l.
A, 9 A, IOA, IIA, photoreceptor belt l
It has the function of making the upper latent image visible using a non-contact development method. Unlike contact development, non-contact development using this one-component or two-component development method has the advantage of not interfering with the movement of the photoreceptor belt l.

Reference numeral 12 denotes a transfer drum that is a transfer member that is in contact with the photoreceptor belt l around the rotary roller 2, and the transfer drum 12 is rotated counterclockwise at the same circumferential speed as the photoreceptor belt l.

The transfer drum 12 has a clamp lever 13 on its circumferential surface for fixing the transfer material, and a transfer device 1 on its inner surface.
4, a transfer material clamp release means 15, and a separator 16.
is arranged in the charger 25.

The transfer device 14 is arranged so as to correspond to the contact point between the photosensitive belt 1 and the transfer drum 12, and the clamp release means 15 and the separator 16 are arranged sequentially on the downstream side of the transfer device 14. The charger 25 is arranged to wrap the transfer material and re-charge the transferred toner image.

A cleaning device 17 includes a blade 17A and a toner conveying roller 17B, which are always in pressure contact with the circumferential surface of the photoreceptor bell l-1 to remove residual toner after image transfer. Reference numeral 26 is a fab run cleaning device for the transfer drum 12 and has a pressure release mechanism.

The process of the color image forming apparatus using 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 image forming system shown in FIG. That is, the data obtained by the color image data input section (FIG. 2 (a)) in which the image sensor scans the original image is input to the image data processing section (FIG. 2 (a)).
Image data is created through arithmetic processing in (b)), which is then stored in the image memory (FIG. 2 (c)). Then, the image memory is taken out during recording and transferred to the recording section (Fig. 2 (D)).
), for example, is input to the color image forming apparatus shown in the embodiment shown in FIG. Wc1.

That is, when a color signal output from an image reading device separate from the printer is input to the laser writing system unit 7, the laser writing system unit 7 outputs 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, and passes through an fθ lens 7C to mirrors 7D and 7E.
The optical path is bent by this, and the light is projected onto the circumferential surface of the photoreceptor belt 1, which has been charged in advance by a charger 6, which is a charging means, 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 movement of the photoreceptor belt 1. This latent image is reversely developed in a non-contact state by a developing device 8 loaded with a yellow developer in the developing means, and a yellow toner image is formed on the circumferential surface of the photoreceptor belt 1. After the obtained toner image is transferred to a transfer material on a transfer drum 12, which will be described later, residual toner is removed by a cleaning device 17, and the next copy cycle begins.

That is, the photoreceptor belt l is charged again by the charger 6, and then the second color signal output from the signal processing section is input to the writing system unit 7, and the second color signal is inputted to the writing system unit 7, and the second color signal is inputted to the writing system unit 7. Similarly, writing is performed on the circumferential surface of the photoreceptor belt 1 to form a latent image. This latent image is the second
The developing device 9 loaded with magenta developer is used for non-contact reversal development to form a magenta toner image, which is superimposed on the already formed yellow toner image of the transfer material on the transfer drum 12. It is formed by

1O is a developing device containing cyan developer, which applies cyan developer to one circumferential surface of the photoreceptor belt based on the image signal generated by the signal processing section.
A cyan toner image is formed on the transfer material on the transfer drum 12 described above so as to be superimposed on the toner image.

Furthermore, 11 is a developing device having a black developer,
A black toner image is superimposed on the transfer material on the transfer drum 12 by the same process. Each of these developing devices 8,
9. A direct current or even alternating current bias voltage is applied to each of the sleeves 10 and 11, and jumping development is performed using an l-component or two-component developer as a developing means, and the photoreceptor whose base is grounded is Reversal development is performed without contacting the belt 1.

Transfer material is supplied to the transfer drum 12 in the following manner.

Paper feed cassette 1 synchronizes with image formation on photoreceptor belt l.
8, the transfer material is carried out by a paper feed roller 19, and only one sheet of the uppermost layer is fed to a timing roller 21 by a separation roller 20. The timing roller 21 starts feeding the transfer material in response to a paper feed signal, fixes the leading end of the transfer material by a clamp lever 13 on the transfer drum 12, and then wraps the transfer material around the drum as it rotates.

The transfer drum 12 is driven at the same circumferential speed as the photosensitive belt 1, and is synchronized with the position of the image developed on the transfer drum 12, and the transfer device 14 sequentially transfers yellow, magenta, cyan, and black toner images as described above. is transferred onto the transfer material.

When the image transfer is thus completed, the clamp release means 15
is activated, the transfer material is released from being fixed by the clamp lever 13, and then the charge is removed in the separator 16 and separated from the drum surface. After being fed to the fixing roller 22 and fixing the image thereon, the transfer material is transferred to the paper ejection roller 23. After that, it is discharged onto the tray 24.

The photosensitive belt 1 and the transfer drum 12, including the cleaning device 17, are arranged in a container-shaped cartridge 3 as shown in the figure.
0 and can be attached to and detached from the main body of the device as an independent process unit.

That is, the cartridge 30 is supported by the apparatus main body by guide members 30A provided on the left and right sides,
It is inserted and removed horizontally from the front of the device via the handle 30B on the front.

Prior to the insertion and removal of the cartridge 30, each of the above-mentioned developing devices is retracted downward to separate the respective developing sleeves from the photoreceptor belt l.

The developing devices are integrated into a flexible developing container 41 in a partitioned state, and placed on a support stand 42 to form a developing device unit 40.

The developing container 41 has a plurality of compression springs 43 disposed in the front and back direction sandwiched between the bottom surface corresponding to the developing devices 8 and 11 and the supporting base 42, so that the circumferential surfaces of the developing sleeves are in contact with each other. The curvature of the curved surface formed by the guide member 4
The photoreceptor bell l-1 is stored in the main body of the apparatus in a state in which it is locked by the claw portion 42A so that the curvature is smaller than the curvature of the image forming surface of the photoreceptor bell l-1 formed by the photoreceptor bell l-1.

The left and right side portions of the support base 42 respectively form a pair of retaining portions 42B in the front and back direction, and are supported by the device main body by inscribing and engaging with an eccentric cam 44 that is pivoted to the device main body. There is.

The rotational phases of each of the eccentric cams 44 are synchronized, and the rotation allows the developing unit 40 to move up and down while maintaining a horizontal state. By rotating the eccentric cam 44 by half a rotation from the angle shown in the figure, It is possible to separate each developing sleeve from the photoreceptor belt l.

Note that if the apparatus main body is constructed in a Talam shell format in which it can be divided into upper and lower halves, and the cartridge 30 is incorporated into the upper main body and the developing device unit 40 is incorporated into the lower main body, the above-mentioned device for retracting the developing device unit 40 downward is not required. Therefore, a fixed support shaft may be provided in place of the eccentric cam 44, and the developing unit 40 can also be configured to be removable from the main body of the apparatus. FIG. 3 shows the state in which the lid is opened in the taram shell format, and with this structure, it is easy to clear jams and replace the cartridge 30 and developer unit 40. . Note that when the lid is opened, the fixing roller 22. The rollers of the paper discharge roller 23 are spaced apart from each other to prevent the transfer paper from being damaged.

Further, as in a cartridge 130 shown in FIG. 4, it is also possible to integrate the photosensitive belt 11, the transfer drum 12, and the developing unit 40, and to attach and detach them from the main body of the apparatus at the same time.

In this case, the eccentric cam 44 is provided inside the cartridge 30, and its rotation operation, that is, the downward retraction operation of the developing device unit 40, is performed after the cartridge 30 is removed from the main body of the apparatus.

When both of the cartridges 30 and 130 described above are removed from the main body of the apparatus, the openings of the charging exposure section, paper feeding section, and paper ejection section on the outer wall of the cartridge are exposed to the shielding plates S1, S2, and S.
3 to prevent damage to the stored equipment or intrusion of dust, etc.

〔Effect of the invention〕

According to the present invention, each image forming means such as an image forming body, a transfer body, and a developing device can be easily attached and detached from the apparatus main body without impairing the relative positional accuracy, and as a result, the image forming unit can be made more compact. This has led to the provision of a transfer type color image forming apparatus that is extremely easy to maintain.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus of the present invention, FIG. 2 is a block diagram showing an image forming system, and FIGS. 3 and 4 are cross-sectional configuration diagrams of a cartridge of the apparatus. l...Photoreceptor belt 4...Guide member 6...
・Charger 7...Laser writing system unit 8.9.10.11...Developer 8 A, 9 A, IOA, IIA...Developer 12.
・Transfer drum 14 ・Transfer device 16 ・Separator 18 ・Paper feed cassette 22 ・Fixing rollers 30A, 130A ・Guide member 41 ・Developer container 44 ・Compression spring Leave 13 ...Clamp lever 15...Clamp release means 17...Cleaning device 21...Timing roller 30.130...Cartridge 40...Developer unit 42...Support stand 31.32. S3...Shielding plate (a) (b) (c) (d)

Claims (2)

[Claims] (1) Color image formation with a plurality of developing units upstream in the moving direction of a belt-shaped image forming body that moves while being stretched between a plurality of rotating rollers, and a transfer body adjacent to the rotating rollers downstream. A color image forming apparatus, wherein the belt-like image forming body and the transfer body constitute an integrally formed process unit that can be inserted and removed. (2) The color image forming apparatus according to claim 1, wherein the belt-shaped image forming body is stretched in a horizontal direction.