JP2001092216A - Color image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color image recording device that an intermediate transfer part is simply constituted in small size and the maintenance property is satisfactory. SOLUTION: Image-forming units 17Bk, 17C, 17M and 17Y provided with a photoreceptor 11, the developing device and a toner containing part, constitutes a rotary body being assembled/arranged in an approximately annular form. An intermediate transfer belt unit 2, housing the intermediate transfer belt 3 and a first transfer roller 4 composed of an elastic body, and provided with a pair of rollers 16 for keeping a nipping quantity constant between the intermediate transfer belt 3 and the photoreceptor 11, is constituted so as to repeat contact/separation with the photoreceptor 11. The image formed on the photoreceptor 11, is transferred on the intermediate transfer belt 3 and moreover is transferred on recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color printer,
The present invention relates to a color image recording apparatus applicable to a color copying machine, a color facsimile, and the like.

[0002]

2. Description of the Related Art In a general color electrophotographic method, a color image is formed by superposing toner images of yellow, magenta, cyan, and black on a transfer material. In this color image forming method, a toner image of each color is sequentially formed on a single photoreceptor, and a transfer material wound around a transfer drum is rotated to repeatedly face the photoreceptor. A transfer drum system that transfers toner images in an overlapping manner, and a plurality of image forming units are arranged side by side,
In general, a continuous superimposing method in which toner images of respective colors are sequentially transferred to a transfer material conveyed by a belt through respective image forming portions and the color images are superimposed.

A color image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 1-252982 is one using the former transfer drum system. FIG. 8 shows an outline of the entire configuration of this conventional example, and the configuration and operation will be briefly described below. In FIG. 8, reference numeral 101 denotes a photoreceptor.
2, developing unit 103, transfer drum 104, cleaner 1
05 is provided. The developing unit 103 includes a Y developing device 106 for forming a yellow toner image, and a magenta M
Developing unit 107, cyan C developing unit 108, black Bk
The developing unit group is rotated, and each developing unit sequentially faces the photoconductor 101 to be in a developable state. During operation, the transfer drum 112 and the photoreceptor rotate at a constant speed in the direction of the arrow while facing each other.

When the image forming operation is started, the photosensitive member 101 rotates in the direction of the arrow, and its surface is uniformly charged by the charger 102. Thereafter, the surface of the photoconductor is irradiated with a laser beam 110 modulated with a signal for forming a first color yellow image, thereby forming a latent image. Next, this latent image is first developed by the Y developing device 106 facing the photoconductor.
To form a yellow toner image. The yellow toner image formed on the photoconductor is transferred to the transfer drum 104.
By the time the transfer drum 1 moves to the position
A single sheet of paper as a transfer material sent from a sheet feeding unit 111 is wound around the outer periphery of the sheet 04 with its tip held by a claw 112, and a yellow toner image on a photoreceptor is placed at a predetermined position on the sheet. Are timed to meet in opposition.

After the yellow toner image on the photoreceptor is transferred to the sheet by the action of the transfer charger 113, the surface of the photoreceptor is cleaned by the cleaner 105 to prepare the next color image formation. Subsequently, magenta, cyan, and black toner images are formed in the same manner. At that time, the developing unit 103 sets each developing device used according to the color to a photosensitive member so as to be in a developable state. The diameter of the transfer drum is large enough to allow the longest sheet to be wound and to replace the developing device between the images of each color.

[0006] Laser beam 110 for image formation of each color
Is performed at a timing such that the toner image of each color on the photoconductor and the toner image already transferred onto the sheet on the transfer drum are aligned and opposed as the rotation is performed. In this manner, the four color toner images are transferred to the transfer drum 10.
4, the image is transferred onto the sheet, and a color image is formed on the sheet. After the toner images of all colors have been transferred, the paper is peeled off from the transfer drum 104 by the peeling claws 114, the toner image is fixed by the fixing device 116 via the transport unit 115, and the paper is discharged out of the apparatus.

On the other hand, as an example of a color image forming apparatus using the continuous transfer method, there is Japanese Patent Application Laid-Open No. 1-250970. In this conventional example, four image forming stations each including a photoreceptor, an optical scanning means, etc. are arranged for forming images of four colors, and the paper conveyed to the belt passes under the respective photoreceptors and the color is transferred. The toner images are superimposed.

Further, as another method of forming a color image by superimposing toner images of different colors on a transfer material, one method is to superimpose toner images of respective colors sequentially formed on a photosensitive member on an intermediate transfer material, Japanese Patent Application Laid-Open No. H2-212867 discloses a method for collectively transferring the toner images on the intermediate transfer material to transfer paper.

[0009]

In the transfer drum system,
A transfer drum is used to align and overlap toner images of different colors. The transfer drum is rotated at the same speed with respect to the photoconductor, and the timing of the leading end of the image is adjusted to match the mutual positions of the toner images of each color when forming a color image. However, in the above configuration, since the paper must be wound around the transfer drum, the diameter of the transfer drum needs to be a certain size or more, and the structure is extremely complicated and high accuracy is required. But it was large and expensive. Strong paper such as postcards and cardboard cannot be used because they cannot be wound around the transfer drum.

On the other hand, the continuous transfer system has an image forming position corresponding to the number of colors, and it is only necessary to pass a sheet through the image forming position. Therefore, such a transfer drum is not necessary. In this case, a plurality of latent image forming means such as a laser optical system for forming a latent image on a photoreceptor are required in accordance with the number of colors, and the structure is very complicated and expensive. Furthermore,
Since there are a plurality of image forming positions, it is difficult to obtain high image quality stably because the relative displacement of the image forming units of each color, the eccentricity of the rotation axis, and the displacement of the parallelism of each unit directly affect the color misregistration. there were. In particular, it is necessary to accurately perform positioning between the colors of the latent image by the latent image forming means.
As described in Japanese Patent Application Laid-Open Publication No. H11-209, there has been a problem that an image exposure system as a latent image forming means requires a considerable device and a complicated configuration.

Further, Japanese Patent Laid-Open No. 2-2 using an intermediate transfer material
In the example of Japanese Patent No. 12867, in order to form toner images of each color on the same photoreceptor, a plurality of developing units must be arranged around a single photoreceptor. And the photoreceptor became a belt shape that was difficult to handle. In addition, if each developing unit is replaced at the time of maintenance, matching adjustment with the characteristics of the photoconductor is required,
When the photoconductor is replaced, it is necessary to adjust the position between the photoconductor and each developing device. Therefore, maintenance of each color developing device and the photoconductor is also difficult.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a color image recording apparatus in which the structure of an intermediate transfer unit is small and simple, has good maintenance, and is stable in transfer and does not cause color misregistration.

[0013]

In order to achieve the above object, a color image recording apparatus according to the present invention transfers an image formed on a photoreceptor to an intermediate transfer belt, and further comprises an apparatus provided on the apparatus side. In a color image recording apparatus that forms an image by transferring an image onto a recording sheet by a retransfer roller and fixing the image, the individual units including the photoconductor, the developing device, and the toner storage unit are collectively arranged in a substantially annular shape. A rotator, an intermediate transfer belt, and an elastic roller for pressing the intermediate transfer belt against the photoconductor are housed, and the nip amount between the intermediate transfer belt and the photoconductor is kept constant by contacting the end of the photoconductor. And an intermediate transfer belt unit having a pair of rollers to rotate the rotating body to sequentially arrange the photoconductors at the image forming position, while maintaining the pressure between the intermediate transfer belt and the photoconductor. · Repeat spacing effect transfer of the color image, and a configuration.

Thus, even when the user attaches and detaches the intermediate transfer belt unit during maintenance, image formation can be started without special adjustment.
In addition, the pressure contact between the intermediate transfer belt and the photoconductor can be kept constant, and the pressure contact nip amount is always constant, so that the photoconductor and the intermediate transfer belt are repeatedly contacted and separated to transfer a color image. Even when the transfer is performed, the transfer performance does not change for each color.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a color image recording apparatus and an intermediate transfer belt unit according to the present invention will be described with reference to FIG. 1 is an outer casing of a color electrophotographic printer,
The right end side of the drawing is the front side. Reference numeral 1A denotes a printer front plate. The front plate can be freely opened and closed as shown by a dotted line with respect to a hinge shaft 1B on the lower side of the printer outer casing 1, and can be freely raised and closed as shown by a solid line. The operation of attaching and detaching the intermediate transfer belt unit 2 to and from the inside of the printer, and checking and maintaining the inside of the printer such as when a paper jam occurs, are performed by opening the front plate 1A to open the inside of the printer.
The attachment / detachment operation of the intermediate transfer belt unit 2 is designed to be in a direction perpendicular to the rotation axis generatrix direction of the photoconductor.

FIG. 2 shows the structure of the intermediate transfer belt unit 2. The intermediate transfer belt unit 2 includes a unit housing 2a, an intermediate transfer belt 3, and a first conductive elastic body.
A transfer roller 4, a second transfer roller 5 composed of an aluminum roller, a tension roller 6 for adjusting the tension of the transfer belt, a belt cleaner roller 7 for cleaning the toner image remaining on the transfer belt, and a toner collected on the cleaner roller 7 It includes a scraper 8 for scraping, a waste toner reservoir 9a and 9b for retaining collected toner, and a position detector 10 for detecting the position of the transfer belt. The intermediate transfer belt unit 2 is a printer front plate 1 shown in FIG.
A is folded down as indicated by a dotted line and opened to be detachable from a predetermined storage portion in the printer outer casing 1.

The intermediate transfer belt 3 is made of an endless belt-like semiconductive urethane film having a thickness of 100 μm, and is formed by molding a low-resistance urethane foam around the periphery to have a resistance of 107 Ωcm. It is wound around the first transfer roller 4, the second transfer roller 5, and the tension roller 6, and is configured to be movable in the arrow direction. Here, the circumferential length of the transfer belt is a length (62 mm) slightly longer than half of the circumferential length of a photosensitive drum (diameter 30 mm) to be described later, in the longitudinal direction length (298 mm) of A4 paper which is the maximum paper size. Is set to 360 mm.

When the intermediate transfer belt unit 2 is mounted on the main body of the printer, the first transfer roller 4 is applied to the photosensitive member 11 (shown in FIG.
kg, and the second transfer roller 5 is pressed through the intermediate transfer belt 3 to a third transfer roller 12 (shown in FIG. 1) having the same configuration as the first transfer roller 4 described above. . The third transfer roller is configured to be rotatable following the intermediate transfer belt 3.

The cleaner roller 7 is a roller of a belt cleaner for cleaning the intermediate transfer belt 3. This is a configuration in which an AC voltage for electrostatically attracting toner is applied to a metallic roller. The cleaner roller 7 may be a rubber blade or a conductive fur brush to which a voltage is applied.

FIG. 3 is a perspective view showing the structure of the position detector 10 using a photo interrupter provided inside the intermediate transfer belt unit 2. A detection hole 13 is provided at an end of the intermediate transfer belt 3, and the position detector 10 optically detects the passage of the detection hole 13 so as to align a color image on the intermediate transfer belt 3. It is.

FIG. 4 shows an arrangement for fixing three rollers of the intermediate transfer belt unit. 4 is a first transfer roller (30 mm in diameter), 5 is a second transfer roller (30 mm in diameter), 6
Is a tension roller (diameter 12 mm), 14 is those 3
It is a side plate for fixing the book roller. Tension roller 6
Always applies tension to the intermediate transfer belt by the spring 15. As shown in the perspective view of FIG. 5, both ends of the first transfer roller 4 have a diameter 28 smaller by 2 mm than the diameter of the first transfer roller.
Two rollers 16 of mm are attached. FIG. 6 shows how the intermediate transfer belt unit contacts the photoconductor. Reference numeral 11 denotes a photosensitive member of the image forming unit, which is pressed against the first transfer roller 4 via the intermediate transfer belt 3. The degree of the pressure contact at this time is defined by the rollers 16, and the pressure contact is always performed with a fixed nip amount without being too strong or too weak. At this time, the intermediate transfer belt 3 is
Although the tension roller 6 is pushed up by the spring 15, the tension roller 6 can be kept constantly at a constant tension even when the image forming unit changes, although the tension roller 6 is more likely to be loosened as compared with the state where it is not in contact. Therefore, it is possible to stably transfer the toner image on the photoconductor to the intermediate transfer belt, and it is possible to prevent the occurrence of color misregistration due to the bending of the intermediate transfer belt.

Returning to FIG. Black in the center of the printer,
Four fan-shaped image forming units 17Bk, 17C, 17M, and 17Y for each color of cyan, magenta, and yellow form an image forming unit group 18 and are arranged in a ring as shown in the figure. Each image forming unit is detachable at a predetermined position of the image forming unit group 18 by opening the printer top plate 1C of FIG. 1 around the hinge shaft 1D. Image forming unit 1
Reference numeral 7 designates a mechanical drive system and an electric circuit system on both the image forming unit side and the printer side which are connected via a mutual coupling member (not shown) by being properly mounted in the printer. Electrically integrated.

Image forming unit 1 arranged in an annular shape
7Bk, 17C, 17M, 17Y is a support (not shown)
, Which is driven by a moving motor 19 as a whole, and is fixed and does not rotate.
It is configured to be rotatable around 0. Each image forming unit is rotated by an image forming position 2 facing a second transfer roller 4 that sequentially supports the intermediate transfer belt 3 described above.
1 can be located. The image forming position 21 is also an exposure position by the laser signal light 22.

Each of the image forming units is made of the same components except for the developer put in the image forming unit. Therefore, the image forming unit 17Bk for black will be described for simplification of description, and the other colors will be omitted. For each color,
The same portions are denoted by the same reference numerals, and if it is necessary to distinguish the configuration of each color, a character indicating each color is appended to the reference numeral. FIG. 7 shows the black image forming unit 17Bk in detail. In this description, the inventors have used the developing method disclosed in Japanese Patent Application No. Hei. In FIG. 7, reference numeral 11 denotes an organic photoreceptor in which phthalocyanine is dispersed in a polycarbonate binder resin; 23, a non-rotating magnet fixed coaxially with the photoreceptor 11; 24, a charging roller for negatively charging the photoreceptor; Reference numeral 25 denotes an exposure window through which the laser beam enters the image forming unit, and reference numeral 26 denotes a developer hopper. Developer hopper 26
Inside, particle size 50μ coated with silicone resin
m ferrite carrier 27Bk and a two-component developer 29Bk obtained by mixing black toner 28Bk in which a black pigment is dispersed in a polyester resin.
Attach to surface. Reference numeral 30 denotes a rotatable collecting electrode roller made of aluminum, 31 denotes a non-rotating magnet coaxially fixed inside, 31 denotes a scraper made of polyphenylene sulfide which scrapes off toner on the collecting electrode roller, 3
Reference numeral 3 denotes an AC high-voltage power supply for applying a voltage to the collection electrode roller. Reference numeral 34 denotes a cleaner for cleaning the toner remaining on the surface of the photoconductor after the transfer. The diameter of the photoconductor 11 is 30 mm, and the photoconductor 11 is rotated in the direction of the arrow at a peripheral speed of 60 mm / s.
Has a diameter of 16 mm and was also rotated in the direction of the arrow at a peripheral speed of 60 mm / s.

Returning to FIG. 1, the description will be continued. Reference numeral 35 denotes a laser exposure device disposed below the inside of the printer outer casing 1, and includes a semiconductor laser, a scanner motor 35a, and a polygon mirror 3.
5b, a lens system 35c, and the like. The pixel laser signal light 22 corresponding to the time-series electric pixel signal of the image information from the laser exposure device 35 is used for the image forming unit 1 shown in FIG.
Through an optical path window 36 formed between 7Bk and 17Y, the light enters a fixed mirror 38 in the shaft 20 through a window 37 opened in a part of the shaft 20, is reflected and is at the image forming position 21. The photosensitive member enters the image forming unit 17Bk substantially horizontally from the exposure window 25 of the image forming unit 17Bk, and passes through a passage between a developer reservoir 26 and a cleaner 34 disposed above and below the image forming unit 17Bk. The light enters the exposure unit on the left side surface of the drum 11 and is scanned and exposed in the generatrix direction.

Here, since the optical path from the optical path window 36 to the mirror 38 uses the gap between the adjacent image forming units 17Bk and 17Y, the image forming unit group 1
8 has very little wasted space. Also, mirror 3
Since 8 is provided at the center of the image forming unit group 18, it can be constituted by a single fixed mirror, and has a simple configuration and easy alignment.

Reference numeral 12 denotes a third transfer roller disposed above the paper feed roller 39 inside the printer front plate 1A, and a nip portion where the intermediate transfer belt 3 and the third transfer roller 12 are brought into pressure contact with each other. A paper transport path is formed so that paper is fed by a paper feed roller 39 provided below the printer front plate 1A.

Reference numeral 40 denotes a paper feed cassette provided on the lower side of the printer front plate 1A so as to protrude outward, and can set a plurality of papers S at the same time. 41a and 41b are paper transport timing rollers, 42a and 42b are fixing roller pairs provided on the upper inside of the printer, 43 is a paper guide plate provided between the third transfer roller 12 and the fixing roller pairs 42a and 42b, 44a
44b is a paper discharge roller pair disposed on the paper outlet side of the fixing roller pairs 42a and 42b, 45 is a fixing oil reservoir for storing a silicone oil 46 supplied to the fixing roller 42a, and 47 is a silicone oil applied to the fixing roller 42a. It is an oil supply roller. The above is the description of the main configuration of the color image recording apparatus of the present invention.

According to the above configuration, the intermediate transfer belt section having a complicated configuration can be unitized. Therefore, when the intermediate transfer belt is deteriorated, the user can replace the entire unit and the maintenance performance is improved.

Further, in a color image recording apparatus in which the photoreceptor and the intermediate transfer belt repeatedly contact and separate as in the present invention, the intermediate transfer belt is easily bent at the time of separation and contact. However, in the present invention, the intermediate transfer is always performed by the tension roller. This is a configuration that applies tension to the belt, and does not cause color shift or the like due to bending.

In the color image recording apparatus according to the present invention, in which the photosensitive member and the intermediate transfer belt repeat contact and separation,
Although it is difficult to keep the pressure contact between the intermediate transfer belt and a plurality of different photoconductors constant, in the present invention, since a roller is provided on the side of the first transfer roller to make contact with the photoconductor, the pressure contact nip amount is always constant. The transfer performance does not change for each color.

Hereinafter, the operation of the color image recording apparatus according to one embodiment of the present invention will be described with reference to FIGS.

First, the operation of the image forming unit will be described with reference to FIG. The photoconductor 11 is charged to the charging roller 24 at -500 V
Was charged. A laser beam scanning light 2 is applied to the photoconductor 11.
Irradiation No. 2 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -100V. On the surface of the photoconductor 11,
The two-component developer 29Bk was applied in the developer hopper 26 by magnetic force. Next, the surface of the photoconductor 11 is collected with the collecting electrode roller 3.
Passed before zero. When the photosensitive member 11 passes through the uncharged area, the electrode roller 30 is supplied with an AC high voltage power supply 33 by +1.
An AC voltage (rectangular wave having a frequency of 3 kHz) of 750 V0-p (1.5 kV peak-to-peak) superimposed with a DC voltage of 00 V was applied. Thereafter, when passing through the surface of the photoconductor 11 on which the electrostatic latent image has been written and charged to -500 V, the AC roller 33 supplies the electrode roller 30 with a 750 V0-p (peak-to-peak) in which a DC voltage of -300 V is superimposed. AC voltage of 1.5 kV peak (rectangular wave of 3 kHz frequency)
Was applied. Then, the developer on the photoconductor 11 and the toner adhering to the non-image portion were collected by the electrode roller 30, and a negative-positive toner image was left only on the image portion on the photoconductor 11. The developer and toner attached to the electrode roller 30 rotating in the direction of the arrow are scraped off by the scraper 32,
It was returned to the developer hopper 26 again and used for the next image formation. Thus, a black toner image was obtained on the photoconductor 11. The same operation was performed for the other developing units 17C, 17M, and 17Y other than black.

Next, the operation of the apparatus shown in FIG. 1 when forming a color image will be described. First, the image forming unit group 18 is at the position shown in FIG. 1, and the black image forming unit 17Bk is at the image forming position 21 as shown. At this time, the photoconductor 11 is in opposing contact with the first transfer roller 4 via the intermediate transfer belt 3. The contact state at this time is such that the surface of the first transfer roller 4 as shown in FIG. 6 is dented by the photoconductor 11 and the roller 16 is in contact with the side end of the photoconductor 11. The deflection of the intermediate transfer belt 3 at this time was absorbed by the tension roller 6. Returning to FIG. In the image forming step of the image forming unit described above, the black signal light is input to the image forming unit 17Bk by the laser exposure device 35, and the image is formed by the black toner. At this time, the image forming unit 17B
k (60 mm / equal to the peripheral speed of the photoreceptor)
s) and the moving speed of the intermediate transfer belt 3 are set to be the same, and the black toner image is transferred to the intermediate transfer belt 3 by the action of the first transfer roller 4 simultaneously with the image formation. At this time, a DC voltage of +1 kV was applied to the first transfer roller. Immediately after all the black toner images have been transferred, the entire image forming units 17Bk, 17C, 17M, and 17Y are driven by the moving motor 19 as the image forming unit group 18 and rotate in the direction of the arrow in FIG. The image forming unit 17C is rotated by 90 degrees and stops at the position where the image forming unit 17C reaches the image forming position 21. During this time, since the portions of the developer hopper 26 and the cleaner 34 other than the photoconductor of the image forming unit are located inside the rotation arc at the tip of the photoconductor 11, the intermediate transfer belt 3 does not contact the image forming unit. .

After the image forming unit 17C arrives at the image forming position 21, the laser exposure device 35 inputs a signal light to the image forming unit 17C with a cyan signal as before, and the cyan toner image is formed and transferred. Done. By this time, the intermediate transfer belt 3 makes one rotation, and the next cyan toner image is positionally matched with the previously transferred black toner image.
The timing of writing the cyan signal light is controlled based on the signal from the position detector 10 shown in FIG. During this time,
The third transfer roller 12 and the cleaner roller 7 are slightly away from the intermediate transfer belt 3, and are configured so as not to disturb the toner image on the transfer belt.

The same operation as described above was carried out for magenta and yellow, and the toner images of four colors were superimposed on the intermediate transfer belt 3 so as to coincide with each other in position and a color image was formed. After the transfer of the last yellow toner image, the four color toner images were collectively transferred to the sheet fed from the sheet feeding cassette 40 at the same time by the action of the third transfer roller 12. At this time, the second transfer roller 5 is grounded, and the third transfer roller 12
, A DC voltage of +1.5 kV was applied. The toner image transferred to the paper was fixed by the pair of fixing rollers 42a and 42b. The sheet was then discharged out of the apparatus via a pair of discharge rollers 44a and 44b. The transfer residual toner remaining on the intermediate transfer belt 3 is cleaned by the action of the cleaner roller 7 to prepare for the next image formation.

Next, the operation in the monochrome mode will be described. In the single-color mode, first, an image forming unit of a predetermined color moves to an image forming position. Next, image formation of a predetermined color and transfer to the intermediate transfer belt 3 are performed in the same manner as before, and the transfer is continued as it is after the transfer.
Was transferred to paper sent from the company and fixed as it was.

Next, maintenance of the apparatus will be described. When the developer of a specific color is consumed and maintenance is performed, first, the image forming unit group 18 is rotated by the action of the moving motor 19 to move the image forming unit of the target color to the upper position (the image in FIG. 1). (Position of forming unit 17C)
Go to And the cover 1D located at the top of the device body
, And the image forming unit of interest is taken out of the apparatus from there. Next, a new image forming unit whose image density has been adjusted in advance is mounted. Thus, after the image forming unit is mounted, image formation can be started without any adjustment.

The life of the intermediate transfer belt 3 is about 30,000 pages. The waste toner accumulated up to this time is accumulated in the waste toner reservoirs 9a and 9b. The user opens the cover 1A located at the front of the apparatus main body, and takes out the intermediate transfer belt unit 2 out of the apparatus. Next, a new unit with a cleaner or the like adjusted in advance is mounted as an intermediate transfer belt unit. Therefore, after the unit is mounted, image formation can be started without any adjustment.

The above is the description of the configuration and operation of the embodiment.
In the above embodiment, a specific structure of the image forming unit is used. However, even in the case of an image forming unit having a structure using a conventional developing method, the essence and the function and effect of the present invention may be changed. Absent.

[0041]

According to the present invention, an intermediate transfer belt unit for use in a color image recording apparatus having a small and simple structure of the intermediate transfer unit and good maintenance performance can be obtained by the above-described structure.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a color image recording apparatus using an intermediate transfer belt unit of the present invention.

FIG. 2 is a configuration diagram of an intermediate transfer belt unit of the present invention.

FIG. 3 is a perspective view showing a configuration of a position detector of the intermediate transfer belt unit of the present invention.

FIG. 4 is a configuration diagram showing how to apply tension to the intermediate transfer belt of the intermediate transfer belt unit of the present invention.

FIG. 5 is a perspective view showing a roller at an end of a transfer roller used in the intermediate transfer belt unit of the present invention.

FIG. 6 is an explanatory diagram showing how to apply tension when the intermediate transfer belt and the photosensitive member of the intermediate transfer belt unit of the present invention are in contact with each other.

FIG. 7 is a configuration diagram illustrating a configuration of an image forming unit used in a color image recording apparatus according to an embodiment of the present invention.

FIG. 8 is a configuration diagram of a conventional color image forming apparatus.

[Explanation of symbols]

 2 Intermediate Transfer Belt Unit 3 Intermediate Transfer Belt 4 First Transfer Roller 5 Second Transfer Roller 6 Tension Roller 11 Photoconductor 12 Third Transfer Roller 15 Spring 16 Roller 17Bk / 17C / 17M / 17Y Image Forming Unit 18 Image Forming Unit Group 21 Image forming position 22 Laser signal light 35 Laser exposure device 38 Mirror

Claims (1)

[Claims] 1. A color image recording apparatus for transferring an image formed on a photoreceptor to an intermediate transfer belt, transferring the image to recording paper by a retransfer roller provided on the apparatus side, and then fixing the image to form an image. , A rotating body constituted by collectively arranging individual units having the photoconductor, a developing device, and a toner storage portion in a substantially annular shape; an intermediate transfer belt; and an elastic roller for pressing the intermediate transfer belt against the photoconductor. And an intermediate transfer belt unit having a pair of rollers that abut on the end of the photoreceptor to make a nip amount between the intermediate transfer belt and the photoreceptor constant. Rotating the photosensitive member to sequentially place the photosensitive member at the image forming position, and transferring a color image by repeatedly pressing and separating the intermediate transfer belt and the photosensitive member. Recording device.