JPH0816046A - Color image forming device - Google Patents

Abstract

PURPOSE:To reduce the number of rotations of an image forming body required for image formation during monochrome image formation and the time required for monochrome image, formation, in a color image formation device in which a color image and a monochrome image are selected and formed. CONSTITUTION:A Scorotron charger 6, a laser write system unit 7, a cleaning means 13, a developing means 8 or 11, and a transcribing means 12 are arranged in order for a photosensitive body belt 1. The cleaning means 13 is brought into contact with the photosensitive body belt 1 and can be brought into contact with it or released from it, the cleaning means 13 is brought into contact with an image forming body, charging and light exposure are performed with transcription residual toner stuck to the photosensitive body bolt 1, thereafter, cleaning developing, and transcription are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming method in which a color toner image or a single color toner image is selectively formed on an image forming body by an electrophotographic method and is transferred onto a transfer material to obtain an image. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus which selects and forms a color toner image or a single color toner image on an image forming body by an electrophotographic method and transfers the image onto a transfer material to obtain an image,
For example, it is described in JP-A-5-61307 and the like and is known. In the image forming apparatus described in the above publication, the image carrier belts are arranged substantially horizontally and horizontally, and a plurality of developing devices are arranged in parallel on the lower surface of the belt with the developing openings thereof facing upward. Then, around the image carrier belt stretched between the two rotating rollers provided to face each other, in the order of forming an image, a charger, an exposure unit by a laser writing system, a cleaning unit, and the above-mentioned unit. Non-contact developing devices for accommodating the yellow, magenta, cyan, and black developers, respectively, and a transfer device that faces the curved surface of the image carrier belt and has a predetermined interval. A fixing device is provided above the transfer device. The transfer device and the charging device are commonly used or they are combined so that they can be switched to a predetermined position on the photosensitive belt. The image forming body rotates at least 5 times during the color image formation by the image forming process of charging, exposure, reversal development, transfer, and cleaning, and the image forming body rotates twice during the monochromatic black image formation by the above process. Is a color image forming apparatus. Color images are recorded one after another on recording paper that is intermittently conveyed by the color image forming apparatus configured as described above. In the conventional image forming apparatus thus configured, the cleaning device and the non-contact developing device are separated from the charging device and the writing system, so that the toner contamination of the optical system such as the laser writing system, the charging device and the transfer device is separated. Can be prevented. Further, by integrating the developing device, the cleaning device, and the photoconductor, it is possible to realize an image forming apparatus that can be downsized and improved in maintenance.

However, in the image forming apparatus described in the above publication, due to the above arrangement, the contact of the cleaning is released during the formation of the single color image and the process of contacting after the transfer is used. It has a drawback that it requires rotation and it takes time to form a monochromatic image.

[0004]

SUMMARY OF THE INVENTION According to the present invention, when a monochromatic image is formed by a color image forming apparatus which selects a color image and a monochromatic image by electrophotography and forms a monochromatic image, the cleaning means is kept in contact. An object of the present invention is to provide a color image forming apparatus that enables high-speed printing by reducing the number of rotations of the image forming body by enabling continuous image formation.

It is another object of the present invention to provide a color image forming apparatus in which the time required for forming a monochromatic image is shortened and the effect of shielding the image exposure light by the transfer residual toner is reduced. .

It is another object of the present invention to provide a color image forming apparatus that shortens the time required to form a monochromatic image and is not affected by the shielding effect of the toner layer.

Further, the invention according to claim 4 is integrally formed with the image forming body so that the toner adhered to the leveling means or the staying means inside the apparatus does not stain the inside of the color image forming apparatus when the image forming body is replaced. An object is to provide a color image forming apparatus to be replaced.

[0008]

The above object can be achieved by the following means. That is, the image forming apparatus according to the invention of claim 1 forms a latent image by exposing the image forming body, charging means for charging the image forming body, and the image forming body charged by the charging means. Exposure means, cleaning means for cleaning the image forming body when it comes into contact with the image forming body and having a mechanism for contacting and releasing the contact with the image forming body, and non-contact reversal development of the latent image with toner. A plurality of non-contact developing means for obtaining a toner image by means of the above, and a transfer means for transferring the toner image developed by the non-contact developing means onto a transfer material. In a color image forming apparatus in which an exposing unit, the cleaning unit, the non-contact developing unit, and the transfer unit are arranged in this order, the cleaning unit releases contact with the image forming body during color image formation, and charges and exposes. ,developing, The toner image superimposed on the image forming body is repeatedly transferred by the rotation of the image forming body, and after the transfer, the toner image is contacted with the image forming body to clean the image forming body. The color image forming apparatus is characterized in that the cleaning means is in contact with the image forming body and performs charging, exposure, cleaning, reversal development and transfer.

The color image forming apparatus according to a second aspect of the present invention is characterized in that the toner is transparent to infrared light and the exposing means exposes the image forming body with infrared light. Color image forming apparatus.

According to a third aspect of the present invention, there is provided a color image forming apparatus, in which the leveling means capable of contacting and releasing the contact with the image forming body,
Alternatively, the color image forming apparatus according to claim 1, further comprising a staying unit.

A color image forming apparatus according to a fourth aspect of the invention is characterized in that the image forming body and the leveling means or the staying means are integrally removable. And

[0012]

In the color image forming apparatus according to the present invention, the latent image is formed by exposing the image forming body, the charging means for charging the image forming body, and the image forming body charged by the charging means. Exposure means for forming, a cleaning means for cleaning the image forming body when it comes into contact with the image forming body and a mechanism for contacting and releasing the contact with the image forming body, and the latent image is not contacted with toner A plurality of non-contact developing means for reversal development to obtain a toner image, and a transfer means for transferring the toner image developed by the non-contact developing means onto a transfer material, and the charging means for the image forming body. In a color image forming apparatus in which the exposing unit, the cleaning unit, the non-contact developing unit, and the transfer unit are arranged in this order, the cleaning unit releases the contact with the image forming body during the formation of a color image to charge the image forming body. , Dew , And development are repeated by rotating the image forming body to transfer the toner image superposed on the image forming body, and after the transfer, the toner image is contacted with the image forming body to clean the image forming body, while a monochrome image is formed. At the time of image formation, the cleaning means is in contact with the image forming body and performs charging, exposure, cleaning, reversal development and transfer.

That is, the present invention is based on the fact that the residual toner after transfer does not adversely affect the formation of a toner image by charging, exposure, cleaning and non-contact reversal development.
That is, at the time of forming a monochromatic image, charging is performed while the transfer residual toner is still attached to the image forming body, and then image exposure is performed. Since the transfer residual toner is small, most of the charges due to corona discharge from the transfer device can charge the image forming body. Also, most of the image exposure light can reach the image forming body without being blocked by light. Further, by using the reversal development method, even if charging unevenness occurs, a portion having a high charging potential corresponds to a non-image portion, so that it has little influence on an image. However, in the non-contact development, it is extremely difficult to remove the toner once attached to the photoconductor as compared with the contact development. Further, if different colors are used in monochromatic image formation, the developing device will mix colors. Therefore, the image forming body which has been charged and image-exposed with the residual toner remaining on the transfer surface is preliminarily cleaned of the residual toner by the cleaning means before the non-contact reversal development, and then the non-contact reversal development means. A toner image is formed and subsequently transferred to the transfer material. Due to the limited contact position between the developing device group, which is the toner scattering source, and the cleaning means, and the fact that the residual toner does not adversely affect the latent image formation due to the operations of the charging means and the exposing means. The color image forming apparatus according to the present invention has a charging unit, an exposing unit, a cleaning unit, a plurality of developing units, and a transfer unit arranged in this order. By configuring the color image forming apparatus as described above, the color image forming apparatus that selects a color image and a single color image to form an image continuously forms a single color image while the cleaning unit is in contact with the color image forming apparatus. By making it possible to form an image in the same manner, it is possible to reduce the rotation required for forming a conventional monochromatic image and to obtain a monochromatic image in a short time.

Further, in the color image forming apparatus according to the invention of claim 2, the toner is transparent to infrared light and the exposing means exposes the image forming body with infrared light. 1 is a color image forming apparatus. That is, the color image forming apparatus according to the second aspect of the present invention can further reduce the influence of the transfer residual toner shielding effect when the transfer residual toner is exposed while the image forming body is exposed. The shield effect of transfer residual toner will be described. The latent image potential formed when recharging and image exposure is performed on the transfer residual toner is determined by the potential of the toner layer and the potential of the photoconductor that receives the light passing through the toner layer. Light reaching the photoconductor is attenuated by absorption and scattering by the toner layer. This effect is the shielding effect of the toner layer. That is, in order to further reduce the effect of the shield effect, by using an infrared light transmissive toner as a black toner and using an infrared laser or an LED having a wavelength of 780 nm or more as an exposure means in combination, the transfer residual toner It is possible to reduce the difference in the surface potential of the image forming body between the case where the image forming body is exposed by passing through and the case where the transfer residual toner is exposed without transmitting. Further, since the reversal development is performed, the influence of uneven charging due to toner is reduced. As described above, the color image forming apparatus according to the second aspect of the present invention is capable of continuously performing the image forming process by reducing the rotation number of the image forming body which is conventionally required when forming a single color image. By shortening the time required to form an image and reducing the effect of the shielding effect of the toner layer, a good monochromatic image can be obtained in a short time.

Further, the color image forming apparatus according to the invention of claim 3 has a leveling means or a staying means capable of contacting and releasing the contact with the image forming body. It is a device.

That is, in the color image forming apparatus according to the third aspect of the present invention, during the image formation, the transfer residual toner adhering to the peripheral surface of the image forming body is rubbed to be dispersed on the image forming body, and the shielding effect of the toner layer is obtained. Leveling means for making the influence of the toner uniform and low, or a staying means capable of abutting and releasing the abutment by keeping the transfer residual toner only in the area corresponding to the image forming area to prevent the influence on charging and image exposure. Thus, the monochromatic image formation of the image forming body can be continuously performed, the time required for the image formation is shortened, and the shielding effect of the toner layer is not affected.

The color image forming apparatus according to the invention of claim 4 is characterized in that the image forming body and the leveling means or the staying means can be integrally attached and detached. It is a forming device.

That is, in the color image forming apparatus according to the fourth aspect of the present invention, the image forming body and the staying means or the leveling means can be integrally attached and detached. Even if toner adheres, it is extremely unlikely that the toner will spill into the color image forming apparatus when the image forming body is replaced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the invention of claim 1 of the present invention is a sectional view showing the construction of a color image forming apparatus in which the image forming body of FIG. 1 is belt-shaped and an image forming system of FIG. 3 is a block diagram shown and a diagram showing the number of rotations of the image forming body at the time of forming the color image in FIG. A second embodiment according to the second aspect of the present invention will be described with reference to the data of spectral characteristics shown in FIG. A color image forming apparatus having a leveling unit and a staying unit according to the third aspect of the present invention will be described with reference to FIGS. 5 to 8 with reference to a third embodiment and a fourth embodiment. Figure 5
6 is a cross-sectional view of a color image forming apparatus 30 having a leveling member at a position along the outer peripheral surface of a photosensitive drum 29. FIG. FIG. 6 is a partially enlarged view of the leveling member. FIG. 7 is a color image forming apparatus having a retaining member at a position along the outer peripheral surface of the photosensitive belt 1.
FIG. 40 is a sectional view of 40. FIG. 8 is a partially enlarged view of the retention member. FIG. 9 is a sectional view of a color image forming apparatus according to the invention of claim 4.

However, the present invention is not limited to this embodiment.

In FIG. 1, the photosensitive belt 1 is a flexible belt-shaped image forming body. A photoconductor is provided on the outer peripheral surface of the photoconductor belt 1. The photosensitive belt 1 is installed between the rotating rollers 2 and 3. The photosensitive belt 1 is conveyed in the counterclockwise direction indicated by the arrow a due to the driving of the rotating roller 2 and the friction between the inner peripheral surface of the photosensitive belt 1 and the rotating roller 2.

The guide member 4 is fixed to the apparatus main body so as to be inscribed in the inner peripheral surface of the photosensitive belt 1. Photoconductor belt 1
Is tensioned by the action of the tension roller 5 so that the inner peripheral surface thereof rubs against the guide member 4. In addition, the guide member 4 is provided with a concave portion in an area unnecessary for image formation,
The resistance due to rubbing is reduced. Of course, this recess may be omitted if the rubbing resistance is low. Also the photoconductor belt 1
Alternatively, it is preferable to provide a low-friction member such as Teflon on the surface of either the photoreceptor belt 1 or the guide member 4 or to form the low-friction member for the purpose of reducing the sliding resistance between the guide members 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.

By providing a developing device and a cleaning device below the photosensitive belt 1, it is possible to prevent the developer from scattering and spilling.

At a position facing the guide member 4 of the photoreceptor belt 1, a scorotron charger 6 as a charging means, a laser writing system unit 7 as an exposing means, and a plurality of developing devices each containing a developer containing a toner of a specific color. Image forming means such as developing devices 8, 9, 10, 11 and the like are provided. And
In order to keep the gap without hindering the movement of the photosensitive belt 1,
It is held outside the photoconductor belt 1 by a gap holding means.

In addition to the illustrated optical system, the laser writing system unit 7 also includes an optical system such as an LED 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, 9A, and 10A keep a predetermined gap from the photosensitive belt 1. , 11A, and has a function of visualizing the latent image on the photosensitive belt 1 by a non-contact developing method. Unlike the contact development, the non-contact development has an advantage that it does not hinder the movement of the photosensitive belt 1.

The transfer device 12 charges the transfer material in order to transfer the toner image visualized on the photosensitive belt 1 to the transfer material,
The charge removing plate 12A removes charge from the transfer material charged by the transfer device 12. The color or monochromatic toner image formed on the peripheral surface of the photosensitive belt 1 is transferred by the transfer device 12 from the paper feeding cassette 14 to the transfer material fed through the paper feeding guide 15. That is,
The transfer material accommodated in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16 so that one of the uppermost layers is unloaded and the timing roller
It is supplied to the transfer device 12 via 17 at the same timing as the image formation on the photosensitive belt 1. The transfer material that has received the image transfer and the charge removal is reliably separated from the photoreceptor belt 1 that suddenly changes its direction along the rotating roller 2 without being affected by the charge removal effect on the image quality such as toner scattering. The image is fused upward by the fixing roller 18 and then discharged onto the tray 90 via the paper discharge roller 19 after being fused.

The cleaning device 13 has a blade 13A as a cleaning member and a blade moving mechanism 13B. The blade moving mechanism 13B is a mechanism for abutting or releasing the blade 13A on the outer peripheral surface of the photosensitive belt 1. The blade moving mechanism 13B is fixed to the rotating shaft while holding the blade 13A. The blade moving mechanism 13B moves the blade 13A as the rotary shaft rotates. The blade 13A is moved in the direction of arrow b in the figure by the blade moving mechanism 13B and abuts on the photosensitive belt 1. On the other hand, the blade 13A that is in contact with the photosensitive belt 1 moves in the direction opposite to the direction indicated by the arrow b in the figure to release the contact. Blade 13
When the photosensitive belt 1 is conveyed while A is in contact with the photosensitive belt 1, the transfer residual toner adhering to the outer peripheral surface of the photosensitive belt 1 is scraped off and cleaned.

That is, the cleaning device 13 is a cleaning means having a mechanism for contacting and releasing contact with the image forming body. The contacting or releasing of the contact of the blade 13A with the photosensitive belt 1 corresponds to the contacting or releasing of the contact of the cleaning means with the image forming body.

The blade 13A is always in contact with the surface of the photoreceptor belt 1 as shown in FIG. That is, while the photoconductor belt 1 is cleaned by the blade 13A, each process of image formation such as charging, exposure, reversal development, and transfer proceeds.

On the other hand, when forming a color image, the blade 13A repeatedly abuts during cleaning and releases the abutment during toner image formation. That is, blade 13A
Is released from contact during the formation of a color image and is kept at a position separated from the surface of the photosensitive belt 1. After the transfer of the color image, the photosensitive belt 1 is contacted. As a result, the transfer residual toner adhering to the outer peripheral surface of the photosensitive belt 1 is scraped off and cleaned by the blade 13A.

The process of forming a single color image by the color image forming apparatus 25 and the process of forming a color image are performed as follows.

First, the process for forming a monochromatic image is performed as follows.

The formation of a monochromatic image according to the first embodiment is performed according to the image forming system of FIG. Image reader
20 is a separate body from the printer, and the image data input unit 21
It has an image data processing unit 22, an image memory 23 and a CPU 24. That is, under the control of the CPU 24, the image data input unit 21
The data obtained by scanning the original image by the image sensor is processed by the image data processing unit 22 to create image data. This image data is temporarily stored in the image memory 23. Next, the image data is taken out from the image memory 23 and input to the color image forming apparatus 25. The color image forming apparatus 25 has a monochromatic / color mode setting unit 26 and a recording unit 27. The monochromatic / color mode setting unit 26 inputs the setting conditions of the operator to the CPU 24 and determines whether the process of the recording unit 27 is monochromatic image forming. Set to one of color image formation. When the image data input to the color image forming apparatus 25 is input to the laser writing system unit 7 of the recording unit 27,
In the laser writing system unit 7, a laser beam generated by a semiconductor laser element (not shown) is rotationally scanned by a polygon mirror 7B rotated by a drive motor 7A shown in FIG. 1, and passes through an fθ lens 7C and mirrors 7D and 7E. Thus, the optical path is bent, and a bright line is formed by being projected onto the outer peripheral surface of the photosensitive belt 1 to which electric charges have been previously applied by the scorotron charger 6.

On the other hand, when the scanning is started, the beam is detected by the index sensor, the modulation of the beam is started corresponding to the image data, and the modulated beam scans the outer peripheral surface of the photosensitive belt 1. Therefore, a latent image corresponding to the image data is formed on the outer 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 subjected to reversal development in a non-contact state by the developing device 11 of the developing means in which black toner (visual medium) is loaded, and a toner image is formed on the belt surface. The photoconductor belt 1 is conveyed while holding the obtained toner image on the belt surface and passes through the transfer device 12. When the photoconductor belt 1 passes through the transfer device 12, the toner image held on the belt surface is transferred to the transfer material.

After the transfer to the transfer material, the photosensitive belt 1 is ready for the next monochromatic image forming process. Photoconductor belt 1
Is a scorotron charger 6 with the transfer residual toner attached.
An electric charge is applied by the laser writing system unit 7, and then a latent image is written by the laser writing system unit 7. The laser beam projected by the laser writing system unit 7 passes through the attached transfer residual toner and reaches the outer peripheral surface of the photosensitive belt 1.

The photosensitive belt 1 on which the latent image has been written passes through the cleaning means 13 while the transfer residual toner remains attached.

Since the blade 13A of the cleaning means 13 is in contact with the photosensitive belt 1 during the formation of a monochromatic image,
The transfer residual toner is cleaned as the photoconductor belt 1 is conveyed. The blade 13A is not released from contact during the formation of a single-color image. Therefore, the photoconductor belt 1 is reliably cleaned by the conveyance before the development by the developing device 11. Further, if the blade 13A is brought into contact with or released from the contact while a part of the peripheral surface of the photosensitive belt 1 is exposed by the laser writing system unit 7, the conveyance of the photosensitive belt 1 is affected by the fluctuation of the torque. Since the exposure position fluctuates, the blade 13A should not be moved during writing.

The cleaned photoreceptor belt 1 is conveyed and the latent image formed before cleaning is subjected to reversal development in a non-contact state by the developing device 11 of the developing means in which black toner is loaded. The black toner image formed on the peripheral surface of the photoconductor belt 1 is transferred onto the transfer material by the transfer device 12, and the next image forming process is completed. The transfer material is fed from the paper feed cassette 14, the image is fused by the fixing roller 18, and then discharged onto the tray 90 via the paper discharge roller 19, which is similar to the image forming process described above.

Further, when a monochromatic image is formed, the image forming process is different from the conventional one, and continuous printing can be performed without wasteful rotation of the image forming body. In addition, since the transfer residual toner is removed by cleaning, color mixing does not occur even when switching to a different single color image. That is, the photoconductor belt 1 is charged and exposed, is subjected to cleaning to remove transfer residual toner, a toner image is formed by a developing device, and a toner image is transferred onto a transfer material by the transfer device 12 to perform an image forming process. Is the end.

Next, the color image forming process of the color image forming apparatus is performed as follows.

The formation of the color image according to the present embodiment is performed according to the image forming system of FIG. 2 similarly to the formation of the monochromatic image. That is, when the formation of a color image is selected by the single color / color mode setting unit 26, the data obtained by the image reading device 20 is input to the image forming device 25 and the laser writing system unit 7 of the recording unit 27. It A latent image 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 according to the color signal. This latent image is subjected to reversal development in a non-contact state by the developing device 8 of the developing means in which yellow (Y) toner (visual medium) is loaded, and a toner image is formed on the belt surface. The obtained toner image passes under the cleaning device 13 which is a cleaning means separated from the peripheral surface of the photosensitive belt 1 while being held on the belt surface, and enters the process of image formation by the next color signal.

When the process of image formation by the next color signal is started, the photoconductor belt 1 is charged again by the scorotron charger 6, and then the second color signal output from the signal processing unit is output by the writing system unit 7. To the photosensitive member surface, and a latent image is formed in the same manner as in the case of the first color signal described above. The latent image is reversely developed in a non-contact state by the developing device 9 loaded with magenta (M) toner as the second color.

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

The developing device 10 has cyan (C) toner,
A cyan (C) toner image is formed on the belt surface based on a control signal generated by the signal processing unit.

Further, a developing device having black (K) toner
11 is formed by superposing a black toner image on the belt surface by the same process. These developing devices 8, 9, 10 and 11
DC or further AC bias is applied to each of the sleeves 8A, 9A, 10A, 11A, and the base body of the photosensitive belt 1 is grounded. The photoconductor belt 1 is designed to be subjected to non-contact jumping development with a one-component or two-component developer.

On the other hand, the photoconductor belt 1 which has finished the transfer onto the transfer material is further conveyed while the transfer residual toner remains attached and passes through the cleaning device 13. When the transfer is completed, the blade 13A facing the rotating roller 3 is pressed against the photosensitive belt 1. The photoconductor belt 1 is a cleaning device 13
After passing, the transfer residual toner on the peripheral surface is cleaned. After the completion of cleaning, the blade is again
13A is separated to start a new image forming process.

As described above, the number of rotations of the photosensitive belt 1 at the time of color image formation by at least the processes of charging, exposing, developing, transferring and cleaning is as shown by the solid line in FIG. The electrostatic latent image formed on the surface of the photosensitive belt 1 by the scorotron charging and exposure is subjected to reversal development with yellow toner. The development period depends on the first rotation and the second rotation because of the arrangement of the developing device 8. In the color image forming apparatus 25 according to the embodiment of FIG. 1, the photosensitive belt 1 is conveyed from the scorotron charging device 6 to the developing device 8 for about half a circumference.
The photosensitive belt 1 is conveyed for about half a round and then for another round, and the developing device 8 performs reversal development with yellow toner.

Next, charging, exposure and reversal development with magenta toner are similarly carried out during two rotations, and cyan toner is supplied from three rotations and black toner is applied from four rotations and development is performed. Due to the arrangement of the respective developing devices, the period during which the development is performed will depend on the next rotation. Therefore 5
By rotation, a color image is formed on the surface of the photosensitive belt 1 with yellow, magenta, cyan, and black toners. Then, the toner image is transferred onto the surface of the transfer material by the transfer device 12 on the color image formed on the photosensitive belt 1 during 5 rotations, and then the photosensitive belt 1 is cleaned by the cleaning device 13. That is, the photosensitive belt 1 rotates 5 times from the first charging, exposure and development to the end of transfer, and rotates once for cleaning. The rotation for cleaning is performed for a period slightly longer than one rotation as shown in FIG. That is, the cleaning means is arranged such that the photosensitive belt 1 is moved in a period from the end of transfer during 5 rotations to the start of 6 rotations.
Abutted against. Further, the cleaning means is released from contact with the photosensitive belt 1 during the period from the end of 6 rotations to the start of exposure for the next image forming process.
Therefore, since the cleaning is completed in the next image forming process, a stable toner image can be formed and a good image can be obtained.
It should be noted that the cleaning means may be brought into contact with the toner during the transfer after the image exposure by the color signal of the fourth rotation is completed.

Next, a second embodiment according to the invention of claim 2 will be described. In the second embodiment, the infrared ray transmitting black toner is used as the black toner of the two-component developer in the developing device 11 in the color image forming apparatus 25 of FIG. Further, the color image forming apparatus 25 uses the laser writing system unit 7 which emits infrared light as a laser beam.

Pigment Yellow 97 is used as a pigment for obtaining an infrared light transmitting black toner in a weight ratio of 3.5 parts by weight, Pigment Red 97
146 was mixed in a weight ratio of 4 parts and Pigment Blue 15 was mixed in a weight ratio of 3 parts. In addition, the pigment obtained by mixing is mixed in a weight ratio of 5
To 10 parts, 100 parts by weight of the main resin (polyester resin), and 6 parts of the release agent (wax) were mixed, melted and kneaded, and pulverized and classified to obtain a toner.

FIG. 4 shows data of the spectral characteristics of the infrared light transmitting black toner. The solid line in FIG. 4 is the data of the spectral characteristics of each pigment. Also, what is shown by a dotted line is the data of the spectral characteristics of the infrared light transmitting black toner.
With this spectral characteristic, a double-sided tape having good transparency is attached to one surface of the OHP sheet to form an adhesive surface. Toner is evenly applied to this adhesive surface and the spectral transmittance is measured. This is O
The spectral transmittance of the toner is corrected by the spectral transmittance of the HP sheet and the double-sided tape. A Hitachi spectrophotometer (HITACHI 330 type) was used for this measurement, and the wavelength range was from 360 nm to 850 nm.

The laser writing system unit 7 uses a semiconductor laser device as a GaAlAs infrared light emitting diode (L manufactured by Matsushita Electric Industrial Co., Ltd.).
Since N 172) is used, the laser beam becomes infrared light.

In order to give the toner the spectral characteristics shown in FIG. 4, the following pigments may be mixed and used. Benzidine Ye
llow) G (C.I. 21090), benzidine yellow C
R (C.I. 21100), Permanent Yellow (Perma
nent Yellow) DHC (product of Hoechst), Brilliant Carmine 6B (C.
I. 15850), Rhodamine 6G Lake (C.
I. 45160), Rhodamine B Lake (C.I. 45170),
Phthalocyanine Blue Non-Crystal (Phthalocya
nine Blue non Crystal) (C.I.74160), Phthalocyanine Green (C.I.74260), Fat (Fa)
・ Yellow 5G, Fat ・ Yellow 3G, Fat ・
Red G, Fat Red HRR, Fat Red 5B, Fat Black HD, Zabon First (Za
pon Fast) · Black RE, Pomelo First Black B, Pomelo First Blue HFL, Pomelo ·
First Red BB, Pomelo First Yellow G, Quinacridone Red (C.I. 465000). The mixture is at least a yellow pigment, a magenta pigment,
Select one pigment from each of the cyan pigments to obtain a black color.

If the exposure means projects infrared light of 780 nm or more, the laser writing system unit 7 shown in the embodiment
However, the exposure means such as an LED may be used.

As shown in this embodiment, the scorotron charger 6, the laser writing system unit 7, the cleaning device 13, the developing devices 8, 9, 10, 11 and the transfer device 12 are arranged in this order on the photosensitive belt 1. By using the infrared image transmitting black toner and the laser writing system unit 7 that emits infrared light as a laser beam in combination in the arranged color image forming apparatus 25, it is necessary to form an image at the time of forming a single color image on the image forming body. It was possible to obtain a color image forming apparatus which shortens the time and is hardly affected by the shielding effect of the toner layer.
Note that yellow, magenta, cyan, and toner are usually transparent to infrared light.

Next, a third embodiment and a fourth embodiment according to the invention of claim 3 will be described. A third embodiment will be described with reference to FIGS. 5 and 6, and a fourth embodiment will be described with reference to FIGS. 7 and 8. FIG. 5 is a cross-sectional view of a color image forming apparatus 30 having a leveling means at a position along the outer peripheral surface of the photosensitive drum 29. FIG. 6 is a partially enlarged view of the leveling means. FIG. 7 is a cross-sectional view of the color image forming apparatus 40 having a retention unit at a position along the outer peripheral surface of the photoconductor belt 1. FIG. 8 is a partially enlarged view of the retention means. The components designated by the same reference numerals are common to the first embodiment shown in FIG. 1 and the third embodiment and the fourth embodiment shown in FIGS. 5 to 8.

In FIG. 5, the color image forming apparatus 30 includes a leveling member 31 as leveling means at a position along the outer peripheral surface of the photosensitive drum 29.
Have. The color image forming apparatus 30 includes a scorotron charger 6, a laser writing system unit 7, and a cleaning device 1 in this order along the outer peripheral surface of the photosensitive drum 29 in the direction of arrow a in the figure.
3, developing devices 8 to 11, a transfer device 12, and a leveling member 31 are provided. Scorotron charger 6, laser writing system unit 7, cleaning device 13, developing devices 8 to 11, transfer device 12
This has been described in the first embodiment. Further, the toner image on the photosensitive drum 29 is transferred onto a transfer material, fixed by the fixing roller 18, and then discharged to the outside of the color image forming apparatus 30.

On the other hand, the leveling member 31 rubs the transfer residual toner adhering to the outer peripheral surface of the photosensitive drum 29 so as to evenly adhere it to the outer peripheral surface of the photosensitive drum 29. Photoconductor drum 29
The outer peripheral surface of is a surface having a photosensitive layer. By the leveling member 31 leveling the transfer residual toner, the effect of the transfer residual toner on the shield effect of the toner layer becomes uniform.

The leveling member 31 will be described with reference to the partially enlarged view of FIG. The leveling member 31 is a conductive brush 32 capable of contacting and releasing contact with the photosensitive drum 29 as shown in FIG. 6 (A).
have. The conductive brush 32 is obtained by densely planting conductive fibers 33 of 10 ³ to 10 ⁸ Ω on a substrate 34. The substrate 34 is rotatably provided on the outer peripheral surface of the photosensitive drum 29 at a position where it does not come in contact with the support member 35 having conductivity and having a rotating shaft. The supporting member 35 is a substrate 34 which is indicated by an arrow c in the figure.
It is supported so as to be rotatable. The board 34 is rotated by a moving mechanism (not shown) as indicated by an arrow c in the figure. As the substrate 34 rotates, the conductive brush
Reference numeral 32 makes contact with or releases contact with the photosensitive drum 29. The conductive brush 32 comes into contact with the photosensitive drum 29 during the formation of a single-color image, and moves and releases the contact during the formation of a color image.

The leveling member 31 may have a conductive rotating brush 36 as shown in FIG. 6 (B). Conductive rotating brush 36
The conductive fibers 33 are densely planted on the rod 37. The rod 37 is made of a conductive material. The conductive rotating brush 36 can be reciprocated by a moving mechanism (not shown) as shown by an arrow c in the drawing so that it can be contacted with and released from the photosensitive drum 29. It is similar to the case. The rod 37 is rotated by a rotating device (not shown). The conductive fibers 33 densely planted according to the rotation of the rod 37 are brought into sliding contact with the photosensitive drum 29 so as to have a relative speed difference. In the figure, the conveying direction of the photosensitive drum 29 is indicated by an arrow a, and the rotating direction of the conductive rotary brush 36 is indicated by an arrow d. In the figure, the photoconductor drum 29 and the conductive rotary brush 36 are arranged so as to go backward at the facing portion, but even if the photoconductor drum 29 is in the forward direction,
It suffices that there is a relative speed difference between the conductive rotary brush 36 and the conductive rotary brush 36.
The conductive brush 36 comes into contact with the photoconductor drum 29 at the time of forming a single-color image, and moves and releases the contact at the time of forming a color image.

The leveling member 31 of the color image forming apparatus according to the invention of claim 3 may be a ground, but an AC power source
AC bias may be applied by 38. Leveling member 31 to the applied 50～500V, potential of the photosensitive member by the AC bias 500～5KH _Z is preferably neutralization. In addition, the toner also receives the vibration and is uniformly dispersed. Further, in order to prevent the toner from being scattered and the leveling member 31 from being contaminated due to the adhesion of the toner, it is preferable to apply a DC voltage of 50 to 200 V having the same polarity as the toner. The surface potential of the photoconductor after completion of transfer differs depending on the site. For this reason, there are some areas where the transfer residual toner is electrostatically attached to the surface of the photoconductor and the other areas where it is difficult to attach them electrostatically. By removing the charge, the transfer residual toner becomes uniform from the photosensitive drum 29. Since the conductive fibers 33 rub against the transfer residual toner that has become easily separated, the transfer residual toner is evenly distributed on the photosensitive drum 29.

Next, monochromatic image formation by the color image forming apparatus 30 of the third embodiment will be described. In the color image forming apparatus 30, the cleaning device 13 and the leveling member 31 are always in contact with the photoconductor drum 29 when forming a single color image. Photoconductor drum
The toner image formed on the peripheral surface of 29 is transferred to the transfer material in the transfer device 12. On the other hand, the photosensitive drum 29, which has finished the transfer onto the transfer material, continues to rotate, and the transfer residual toner is evened out by the leveling member 31. Subsequently, the photosensitive drum 29 is charged by the scorotron charger 6 and then a latent image is formed by the laser beam by the laser writing system unit 7. The photoconductor drum 29 continues to rotate even after the latent image is formed, and the transfer residual toner uniformly leveled by the leveling member 31 is removed by the cleaning device 13 as the photoconductor drum 29 rotates. The photoconductor drum 29 continues to rotate and a toner image is formed by the developing device 11, and the formed toner image is transferred to a transfer material by the transfer device 12, and the monochromatic image forming process is completed.

Although the conductive brush 32 and the conductive rotating brush 36 are given as examples of the leveling member 31, other shapes may be used as long as the transfer residual toner can be evened out.

In the color image forming apparatus 30, the leveling member 31 is released from contact when forming a color image. Therefore, color image formation is performed in the same manner as in the first embodiment in which the leveling member is not provided.

Next, a fourth embodiment will be described with reference to FIGS. 7 and 8. In the fourth embodiment, the components designated by the same reference numerals in the first embodiment shown in FIG. 1 and the fourth embodiment shown in FIG. 7 are common.

In FIG. 7, the color image forming apparatus 40 has a staying member 41 as a staying means instead of the leveling means at a position along the outer peripheral surface of the photosensitive belt 1. The color image forming apparatus 40 includes a scorotron charger 6, a laser writing system unit 7, a cleaning device 13, developing devices 8 to 11, a transfer device 12, and a retention device in order along the outer peripheral surface of the photoconductor belt 1 in the direction of arrow a in the figure. A member 41 is provided. Further, the toner image on the photosensitive belt 1 is transferred onto a transfer material, fixed by the fixing roller 18, and then discharged to the outside of the color image forming apparatus 40.

On the other hand, the staying member 41 collects transfer residual toner adhering to the peripheral surface of the photoreceptor belt 1 at the contact portion between the photoreceptor belt 1 and the staying member 41. Since the staying member 41 collects the transfer residual toner in this way, the charge application by the scorotron charger 6 and the writing by the laser writing system unit 7 are performed in a state where the transfer residual toner is not attached to the photosensitive belt 1. Be seen. Since the transfer residual toner does not adhere to the photosensitive belt 1, the charging unevenness due to the transfer residual toner and the shielding effect of the toner layer are eliminated.

The retention means may be a mechanical retention means or an electrical retention means. FIG. 8A shows a staying means having a staying blade 42 which is a mechanical staying means, and FIG. 8B shows an electric staying means having a staying roller 44 to which a bias is applied. .

In FIG. 8A, the stay blade 42 is made of an elastic material. The retention blade 42 is fixed to the support member 43.
The support member 43 supports the staying blade 42 so that the staying blade 42 can come into contact with the photoreceptor belt 1 and can be released therefrom. The support member can move back and forth. The stay blade 42 moves as the support member 43 reciprocates, as indicated by an arrow e in the figure. The solid line in the figure shows the state where the staying blade 42 is in contact with the photosensitive belt 1, and the dotted line shows the state where the staying blade 42 is released from the contact and separated from the photosensitive belt 1. The transfer residual toner is blocked by the contact portion between the staying blade 42 and the photosensitive belt 1. The transfer residual toner is blocked by the staying blade 42 and stays on the upstream side of the staying blade 42 on the photoconductor belt 1 while corresponding to the toner image forming area.
The contact portion is a contact portion when the stay blade 42 is used as the stay means. In the figure, black dots are residual toner or residual toner remaining on the photosensitive belt 1.

The residual transfer residual toner that has stayed moves to the cleaning means 13 when the staying blade 42 is released from the contact in the non-image forming area, along with the conveyance of the photosensitive belt 1. The transfer residual toner is scraped off by the cleaning means 13 and the cleaning is completed. Retention blade as retention means
In the color image forming apparatus having 42, releasing the retention means releasing the contact of the retention blade 42. It is not necessary for the retention means to completely retain the transfer residual toner, and therefore, the contact force may be set so as not to cause uneven rotation on the image forming body at the time of contact or contact release. Alternatively, as the retention release, the contact force may be reduced without allowing the contact release to pass the retained toner.

In FIG. 8B, the stay roller 44 is an electrode roller 45.
And a bias power supply 46. Electrode roller 45 is 10 ² to 10 ⁸ Ω
Is provided on the surface and is rotatably supported by a conductive rotating shaft 47 at a position in contact with or not in contact with the photosensitive belt 1. The electrode roller 45 is pivotally supported by a rotating shaft 47 and rotates in the direction of arrow f in the figure. A bias voltage is applied to the electrode roller 45 by a bias power supply 46. The bias power supply 46 is at least
A first bias voltage capable of attracting the transfer residual toner from the photosensitive belt 1 to the electrode roller 45, and a second bias voltage capable of adhering the transfer residual toner attracted to the electrode roller 45 to the photosensitive belt 1 again.
The bias voltage can be changed to the bias voltage of. When a first bias voltage of 100 to 500 V having a polarity opposite to that of the toner is applied to the electrode roller 45, the transfer residual toner is adsorbed by the electrode roller 45 and stays on the peripheral surface of the electrode roller 45. When a second bias voltage of 100 to 500 V having the same polarity as the toner is applied to the electrode roller 45, the transfer residual toner moves away from the electrode roller 45 and moves again onto the peripheral surface of the photosensitive belt 1. The AC 50~200V, it is preferable to facilitate the movement of the toner to be applied by superimposing 500~5KH _Z. FIG. 8B shows a state in which the toner is attached to the electrode roller 45 by applying the first bias voltage. In the figure, black dots are residual toner that has accumulated or adhered to the photosensitive belt 1. The transfer residual toner moves from the photosensitive belt 1 to the electrode roller 45 by the applied first bias voltage. When the electrode roller 45 is used as the staying means, the first bias voltage is applied during the period corresponding to the toner image forming area. Releasing the retention means changing the bias voltage to the second bias voltage in the non-image forming area of the toner image and moving the transfer residual toner adhering to the electrode roller 45 to the image forming body.

Next, the monochromatic image formation by the color image forming apparatus 40 of the fourth embodiment will be described. In the color image forming apparatus 40 of the fourth embodiment, the cleaning device 13 is always in contact with the photosensitive belt 1 when forming a single color image. On the other hand, the retention unit 41 retains the transfer residual toner in the image area, and releases the retention unit 41 between images during non-image formation or continuous printing.

The toner image formed on the peripheral surface of the photosensitive belt 1 is transferred to the transfer material by the transfer device 12. on the other hand,
Since the photosensitive belt 1 that has been transferred to the transfer material is further conveyed, the transfer member residual toner is retained by the retention member 41. Subsequently, the photoreceptor belt 1 is charged by the scorotron charger 6 and then the laser writing system unit 7
A latent image is formed by the laser beam. The photoconductor belt 1 is continuously rotated to form a toner image by the developing device 11, and the formed toner image is transferred to the transfer material by the transfer device 12, and the image forming process is completed.

The staying member 41 releases the stay between images or during non-image formation. When the stay member 41 releases the stay, the remaining transfer residual toner adheres to the photosensitive belt 1 again. The transfer residual toner that has adhered again is removed as the photoconductor belt 1 is conveyed because the cleaning unit 13 is in contact with the photoconductor belt 1.

When the stay member 41 releases the stay between images, the transfer residual toner adheres to the non-image area of the photosensitive belt 1. Since the latent image is not formed in the non-image area, even if the transfer residual toner adheres, it is not affected by the shielding effect of the toner layer.

Further, even when the staying member 41 releases the staying during non-image formation, the latent image is not formed, so that the shield effect of the toner layer does not affect the latent image.

As described in the third and fourth embodiments, the leveling means or staying means of the color image forming apparatus according to claim 3 is means for reducing the influence of the shielding effect of the toner layer. . That is, the leveling member described in the third embodiment makes the distribution of the transfer residual toner on the image forming body uniform and uniformly reduces the influence of the shielding effect of the toner layer. The staying member described in the fourth embodiment temporarily stays the transfer residual toner to eliminate the influence of charging and shielding effect of the toner layer.

Then, as shown in this embodiment, the scorotron charger 6, the laser writing system unit 7, the cleaning device 13, and the developing device 8 are attached to the drum or belt-shaped photosensitive member.
To 11, the transfer device 12, and the staying means are arranged in this order, in the color image forming apparatus 40, by combining the leveling means and the staying means for reducing the influence of the shield effect of the toner layer, a single color of the image forming body is obtained. In addition to shortening the time required for image formation during image formation, the toner layer is not affected by the shielding effect.

Next, a fifth embodiment according to the invention of claim 4 will be described with reference to FIG.

FIG. 9 is a cross-sectional view of the color image forming apparatus 50 having the retention means at a position along the outer peripheral surface of the photosensitive belt 1. The first embodiment shown in FIG. 1 and the fifth embodiment shown in FIG.
In the embodiment of the present invention, the components having the same reference numerals are common.

The color image forming apparatus 50 has a staying member 41 at a position along the outer peripheral surface of the photosensitive belt 1. Similar to the fourth embodiment, the color image forming apparatus 50 includes a scorotron charger 6, a laser writing system unit 7, and a cleaning device along the outer peripheral surface of the photosensitive belt 1 in the order of arrow a in the figure.
13, a developing device 8 to 11, a transfer device 12, and a staying means 41 are provided. Further, the toner image on the photoconductor belt 1 is transferred onto the transfer material, fixed, and then discharged to the outside of the color image forming apparatus 50.

On the other hand, the retention member 41 is also similar to that of the third embodiment, and retains the transfer residual toner adhering to the outer peripheral surface of the photosensitive belt 1.

The cartridge 51 includes a photosensitive belt 1, a scorotron charger 6, and a staying means as indicated by a chain line in the drawing.
The cartridge 41 and the cleaning means 13 are hermetically sealed. However, the cartridge 51 has slit-shaped openings at positions corresponding to the laser writing system unit 7, the developing devices 8 to 11 and the transfer device 12. The cartridge 51 is detachably attached to the color image forming apparatus 50.

The color image forming apparatus 50 is configured as described above, and the monochromatic image formation and the color image formation are performed in the same manner as the color image forming apparatus 40 shown in the fourth embodiment.

Further, although the cartridge 51 has shown the one in which the photosensitive belt 1 and the staying means are detachably integrated, a developing device may be further integrated. Further, it may have a leveling means instead of the retention means. Further, instead of the photosensitive belt 1, the photosensitive drum 29 may be provided as in the color image forming apparatus 30. Furthermore, since it is not necessary to replace the contacting and contact releasing means of the leveling member or the retention means,
It is desirable to install it separately from the cartridge 51 on the main body side.

[0088]

With the color image forming apparatus according to the first aspect of the present invention, the number of rotations of the image forming body at the time of forming a single color image by the color image forming apparatus for selecting a color image and a single color image to form an image. Since the time required for forming a monochromatic image is shortened by reducing the number of times, it is possible to obtain a monochromatic image in a short time.

In the color image forming apparatus according to the second aspect of the present invention, the number of rotations of the image forming body at the time of forming a monochromatic image is reduced to shorten the time required for forming the monochromatic image, and the toner layer is formed. By reducing the influence of the shield effect due to, it is possible to obtain a good monochromatic image in a short time.

In the color image forming apparatus according to the third aspect of the present invention, the number of rotations of the image forming body when forming a monochromatic image is reduced to shorten the time required for forming the monochromatic image, and the toner layer is formed. Since it is not affected by the shield effect due to, it is possible to obtain a good monochromatic image in a short time.

Further, according to the color image forming apparatus of the fourth aspect of the present invention, even if the remaining transfer residual toner or the leveled transfer residual toner adheres, the toner remains in the color image forming apparatus when the image forming body is replaced. Since the spillage of the color image is extremely small, it is possible to realize a color image forming apparatus which does not stain the inside of the color image forming apparatus and does not deteriorate the image due to toner scattering.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a color image forming apparatus according to a first embodiment.

FIG. 2 is a block diagram showing the image forming system of the above.

FIG. 3 is a diagram showing the number of rotations of the image forming body during color image formation according to the first embodiment.

FIG. 4 is a view showing data of spectral characteristics of toner of the second embodiment.

FIG. 5 is a sectional view of a color image forming apparatus having a leveling member according to a third embodiment.

FIG. 6 is a partially enlarged view of a leveling member according to a third embodiment.

FIG. 7 is a sectional view of a color image forming apparatus having retention means according to a fourth embodiment.

FIG. 8 is a partially enlarged view of a retaining means according to a fourth embodiment.

FIG. 9 is a sectional view showing the arrangement of a color image forming apparatus according to the fifth embodiment.

[Explanation of symbols]

 1 photoconductor belt 2 rotating roller 3 rotating roller 6 scorotron charger 7 laser writing system unit 8 developing device (yellow) 9 developing device (magenta) 10 developing device (cyan) 11 developing device (black) 12 transfer device 13 cleaning Device 13A Blade 13B Blade moving mechanism 18 Fixing roller 20 Image reading device 21 Image data input unit 22 Image data processing unit 23 Image memory 24 CPU 25 Color image forming device 26 Single color / color mode setting unit 27 Recording unit 29 Photosensitive drum 30 color Image forming device 31 Leveling member 32 Conductive brush 33 Conductive fiber 34 Substrate 35 Supporting member 36 Conductive rotating brush 37 Bar 38 AC power supply 40 Color image forming device 41 Retaining member 42 Retaining blade 43 Supporting member 44 Retaining roller 45 Electrode roller 46 Bias power supply 47 Rotation axis 50 Color image forming device 51 Cartridge

Claims (4)

[Claims] 1. An image forming body, charging means for charging the image forming body, exposing means for exposing the image forming body charged by the charging means to form a latent image, and the image forming body. Cleaning means for cleaning the image forming body when it comes into contact with the image forming body, and a plurality of non-contact means for non-contact reversal development of the latent image with toner to obtain a toner image. A contact developing unit and a transfer unit for transferring the toner image developed by the non-contact developing unit onto a transfer material. The charging unit, the exposing unit, the cleaning unit, and the non-contacting unit for the image forming body. In a color image forming apparatus in which a contact developing means and the transfer means are arranged in this order, the cleaning means releases contact with the image forming body during color image formation, and charging, exposure and development of the image forming body are performed. Rotate In return, the superimposed toner image is transferred onto the image forming body, and after the transfer, the image forming body is contacted with to clean the image forming body. A color image forming apparatus which is brought into contact with, and performs charging, exposure, cleaning, reversal development, and transfer. 2. The color image forming apparatus according to claim 1, wherein the toner is transparent to infrared light and the exposing means exposes the image forming body with infrared light. 3. The color image forming apparatus according to claim 1, further comprising a leveling unit or a staying unit capable of contacting and releasing the contact with the image forming body. 4. The color image forming apparatus according to claim 3, wherein the image forming body and the leveling unit or the staying unit are integrally detachable.