JPH06250451A - Color image forming device - Google Patents

Abstract

PURPOSE:To prevent the staining of a transfer material with toner leaked from a cleaning device. CONSTITUTION:This color image forming device has such a structure that the bottom surface of a photosensitive belt l is the transfer part, of an image and a transfer roller 12 and a cleaning device 13 are installed on the lower side of the feeding path of the transfer material, to prevent the sticking of the toner leaked from the cleaning device 13 to the front surface of the transfer material, that is, the transfer surface of the image and is constituted so that at the time of transferring the image, the transfer roller 12 is in contact with a belt surface to transfer the image onto the transfer material and after the transfer, the blade 14 of the cleaning device 13 is pressed to be in contact with the belt surface, to remove residual toner, as a characteristic.

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 in which a toner image is formed on an image forming body by an electrophotographic method, the toner image is neutralized and then transferred onto a transfer paper to obtain an image.

[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 Japanese Patent Laid-Open No. -100770, a latent image is formed and developed on a photoconductor drum, which is an image carrier, according to the number of separated colors of an original image, and the latent image is transferred to a transfer drum each time the image is developed. There is a method in which a multicolor image is formed on the surface and then transferred onto a recording paper to obtain a color copy.

Further, a method of obtaining a color image by repeatedly forming a latent image on the photosensitive drum according to the number of separated colors of the original image and developing with a color toner, superimposing the color toner image on the photosensitive drum and then transferring it. There is. The basic process for forming this multicolor image is described in Japanese Patent Application Laid-Open No. 60-75850 and 60
-76766, 60-95456, 60-95458, 60-15
It is disclosed by Japanese Patent No. 8475.

As for the image forming body, a belt in which the photoconductor is applied or mounted on a flexible belt together with a photosensitive drum having the photoconductor coated or vapor-deposited on the drum peripheral surface as described above. Image-formers have also been proposed. Belt-shaped image forming body (hereinafter also referred to as a photoconductor belt)
Since the shape is determined by being stretched between the rotating rollers including the driving roller, it is effective when the space is effectively used to form an image forming apparatus having a compact shape. In addition, since the photoconductor belt can run along a small curvature, it is possible to prevent transfer material separation failure by separating the transfer material using a small-diameter rotating roller and utilizing this curvature portion. it can.

[0005]

Regardless of whether the drum-shaped or belt-shaped photosensitive member is used, when the image transfer portion is installed on the peripheral surface portion below them, the upper surface of the transfer material becomes the image surface. As a result, the toner dropped or scattered from the cleaning device or the like adheres to the image surface of the transfer material and the image quality may be significantly impaired.

As a result of solving and improving this point, the present invention provides
It is an object of the present invention to provide a color image forming apparatus capable of effectively preventing stains on a transferred image due to cleaning and always recording a high quality image.

[0007]

In the color image forming apparatus having a plurality of developing devices, transfer means and cleaning means arranged around an image forming body, the above-mentioned object is to supply a transfer material to be fed to the apparatus. This is achieved by a color image forming apparatus characterized in that the image forming body and the plurality of developing devices are arranged on one side of the feeding path, and the transfer means and the cleaning means are arranged on the other side.

[0008]

FIG. 1 is a block diagram of a color image forming apparatus according to the present invention.
Through FIG.

In FIG. 1, reference numeral 1 denotes a flexible OPC photosensitive belt which is a belt-shaped image forming body, and the photosensitive belt 1 is provided between rotating rollers 2 and 3 and includes a rotating roller 2.
It is conveyed clockwise by the drive of.

Reference numeral 4 denotes a support member, that is, a guide member fixed to the main body of the apparatus so as to be inscribed in the photosensitive belt 1.
The inner peripheral surface of the photosensitive belt 1 is rubbed against the guide member 4.

Therefore, the photoconductor on the outer peripheral surface of the photoconductor belt 1 is always kept in a constant relation position with respect to the surface of the guide member 4 even during conveyance, so that a stable image forming surface can be formed. .

Reference numeral 6 denotes a scorotron charger, which is a charging means, and 7
Is a laser writing system unit as an image exposing means, 8 to 1
Reference numeral 1 designates a plurality of developing means, that is, developing devices, each containing a developer of a specific color, and these image forming means are arranged so as to face the outer peripheral surface of the photosensitive belt 1 with the guide member 4 on the back side. Set up.

In addition to the illustrated optical system, the laser writing system unit 7 also includes an optical system in which a light emitting portion and a converging optical transmission body are integrated.

The developing units 8, 9, 10, and 11 contain, for example, yellow, magenta, cyan, and black developers, respectively, and the developing sleeves 8A and 9A that maintain a predetermined gap with the photosensitive belt 1. , 10A, 11A, and has a function of visualizing the latent image on the photoconductor belt 1 by a non-contact developing method. Unlike the contact development, this non-contact development has an advantage that it does not hinder the movement of the photosensitive belt.

A transfer roller 12 is a transfer means, and a cleaning device 13 is a cleaning device.
The numeral 13 includes a blade 14 and a waste toner box 15 is integrated.

The transfer roller 12 and the cleaning device 13 are held in a rectangular frame 16 via support shafts 12A and 13A that rotatably support the transfer roller 12 and the cleaning device 13, respectively, and are rotated clockwise by their own weight. It is in contact with the respective stoppers 12B and 13B.

The frame body 16 is supported by the main body of the apparatus so as to be movable in the horizontal direction through a pair of elongated holes 16A provided on both side surfaces, and is a motor which meshes with a rack tooth profile 16B at the lower edge of the frame body 16. It is adapted to be slid by the rotation of the M pinion P.

The frame 16 is further provided with a cam member 17 fixed to a rotating shaft 17A on the lower side thereof, and the cam member 17 is rotated counterclockwise by driving the rotating shaft 17A. The transfer roller 12 or the cleaning device 13 can be rotated counterclockwise.

The color image forming process by the color image forming apparatus is performed as follows. First, in forming a color toner image on the peripheral surface of the photosensitive belt 1, the frame 16 and the cam member 17 are kept at the positions shown in FIG.
Therefore, the transfer roller 12 and the cleaning device 13 are both retracted from the peripheral surface of the photosensitive belt 1 and separated from each other.

First, the formation of a multicolor image according to this embodiment is performed according to the following image forming system. In other words, the image data processing unit performs arithmetic processing on the data obtained by the color image data input unit where the original image is operated by the image pickup device to create image data, which is once stored in the image memory. Next, the image memory is taken out at the time of recording and is inputted to a color image forming apparatus which is a recording unit, for example, shown in the embodiment of FIG.

That is, when a color signal output from an image reading apparatus separate from the printer is input to the laser writing system unit 7, the laser writing system unit 7 generates a semiconductor laser (not shown). The laser beam is rotated by the drive motor 7A. The polygon mirror 7 is rotated.
It is rotated by B, passes through the fθ lens 7C, and then the mirror 7
The optical path is bent by D and 7E, and a bright line is formed by being projected onto the peripheral surface of the photosensitive belt 1 to which electric charges have been previously given by the charger 6 as a charging means.

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. Therefore, 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 yellow (Y) in the developing means.
Is developed by the developing device 8 loaded with the toner (visual medium), and a toner image is formed on the surface at the first round of the belt. The obtained toner image enters the next copy cycle while being held on the belt surface.

That is, the photosensitive belt 1 enters the second round and is recharged by the charger 6, and then the second color signal output from the signal processing unit is input to the writing system unit 7, and Writing to the surface of the photoconductor belt 1 is performed in the same manner as in the case of the first color signal, and a latent image is formed. The latent image is developed by the developing device 9 loaded with magenta (M) toner as the second color.

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

Numeral 10 is a developing device having a cyan (C) toner, and the photosensitive belt 1 forms a cyan (C) toner image on the surface of the photosensitive belt 1 in the third lap on the basis of a control signal generated in the signal processing section. To do.

Further, reference numeral 11 denotes a developing device having black toner, which forms a black toner image on the surface of the belt in the fourth round by superimposing the same process. A DC or further AC bias is applied to each sleeve of each of these developing devices 8, 9, 10 and 11 to perform jumping development by a two-component developer which is a developing means, and a photoreceptor whose base is grounded. The belt 1 is adapted to be subjected to reversal development in a non-contact manner. As the development, non-contact development using a one-component developer can also be used.

The color toner image thus formed on the peripheral surface of the photosensitive belt 1 is conveyed to the image transfer portion at the fifth round of the belt.

In the case of a monochrome image, only the black image is developed by the developing device 11, and the image is transferred on the second round of the belt.

By thus transferring the image after the toner image has been formed, it is possible to prevent the latent image from being formed and disturbed due to fluctuations in the speed of the photosensitive member during transfer.

When the photosensitive belt 1 enters the fifth round, the operations of the charging device 6, the laser writing system unit 7 and the developing devices are stopped in synchronization therewith, and at the same time, the rotating shaft 17A.
The power is transmitted to the cam member 17 and the cam member 17 is driven to a position rotated by approximately 90 degrees in the counterclockwise direction.

As a result, as shown in FIG.
12 rotates counterclockwise around the support shaft 12A as a fulcrum, is pressed against the peripheral surface of the photoconductor belt 1 and rotates in the same direction with the same circumference, and starts the transfer action.

On the other hand, one of the uppermost layers of the transfer material contained in the paper feed cassette 20 is carried out by the rotation of the paper feed roller 21 and the double feed prevention roller 22, and an image is formed on the photosensitive belt 1 via the timing roller 23. And is supplied to the transfer unit at the same timing.

At the transfer portion, the toner image on the photosensitive belt 1 is efficiently transferred to the transfer material by the transfer action of the transfer roller 12 and the image recording is completed.

The transfer material which has received the transfer of the image is surely separated from the photosensitive belt 1 which suddenly changes its direction along the rotating roller 3 and goes upward, and after the image is fused by the fixing roller 5. It is discharged onto the tray 25 via the paper discharge roller 24.

On the other hand, when the transfer of the image is completed, the cam member 17 is rotated clockwise by the power of the rotating shaft 17A to return the transfer roller 12 to the state shown in FIG. 1, and then the motor M is driven. As a result, the frame body 16 is slid to the left as shown in FIG. 3, and the cam member is again moved through the rotary shaft 17A.
Rotate 17 counterclockwise.

As a result, the cleaning device 13 rotates counterclockwise around the support shaft 13A as a fulcrum to elastically press the blade 14 against the peripheral surface of the photosensitive belt 1 to remove the toner remaining on the belt. Perform cleaning.

When the photosensitive belt 1 makes one round and the cleaning operation is completed, the cam member 17 is rotated clockwise to return the cleaning device 13 to the state shown in FIG.
Then, by rotating the motor M in the reverse direction, the frame 16 is slid to the initial position shown in FIG. 1 to complete a series of image recording.

Since the cleaning device 13 is located below the transfer material feeding path, the possibility that it will adhere to the image surface of the transfer material is extremely small even if some toner leakage occurs. By removing 16, the waste toner box 15 and the waste toner box 15 can be taken out of the apparatus, so that replacement and disposal are easy.

Further, the frame 16 is further provided with the charger 6 described above.
It is also possible to rotatably install it and position it on the peripheral surface of the photoconductor belt 1 by the pressing action of the same cam member 17 to the transfer roller 12 and the cleaning device 13 described above to perform the charging action.

The developing device and the photoconductor belt 1 are
By opening the side cover 30 of the main body of the apparatus, they are individually attached or detached as a unit as a cartridge, while the cleaning device 13 and the waste toner box 15 open the side cover 31 of the mounting portion of the paper feed cassette 20. It is attached and detached by.

Further, in FIG. 4, the transfer roller 112 and the cleaning device 113 are supported between a pair of crank members 40 which are integrated via a rotary shaft 40A, and the rotary solenoid S drives the transfer roller 112 and the transfer roller 112. Cleaning device 1
It shows an example configured to switch 13 positions,
When the solenoid S is rotated clockwise, the transfer roller 112 comes into contact with the peripheral surface of the photosensitive belt 1, and when rotated counterclockwise, the blade 113A of the cleaning device 113 causes the peripheral surface of the photosensitive belt 1. Is pressed against.

[0042]

As described above, according to the present invention, the risk of the transferred image being contaminated by the adhesion of toner is extremely reduced, and as a result, a color image forming apparatus capable of always recording a high quality image is provided. .

[Brief description of drawings]

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

FIG. 2 is a cross-sectional configuration diagram of the device during image transfer.

FIG. 3 is a cross-sectional configuration diagram of the device during cleaning.

FIG. 4 is an explanatory diagram showing an example of switching between transfer and cleaning.

[Explanation of symbols]

 1 photoconductor belt 5 fixing roller 6 charger 7 laser writing system unit 8, 9, 10, 11 developing device 12, 112 transfer roller 13, 113 cleaning device 14, 114 blade 15, 115 waste toner box 16 frame 20 paper feed Cassette 30, 31 Side cover 40 Crank member M Motor S Rotary solenoid

Front Page Continuation (72) Inventor Tadayoshi Ikeda 2970 Ishikawacho, Hachioji City, Tokyo Konica Stock Company

Claims (2)

[Claims] 1. A color image forming apparatus having a plurality of developing devices, transfer means and cleaning means around an image forming body, wherein the image is provided on one side of a feeding path of a transfer material fed to the apparatus. A color image forming apparatus comprising: a forming body and the plurality of developing devices, and the transfer means and the cleaning means arranged on the other side. 2. The color image forming apparatus according to claim 1, wherein the transfer means and the cleaning means are alternately moved to face the image forming body during image formation by the apparatus.