JP2001056591A - Color image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color image recording device which can be miniaturized by simplifying the constitution of a toner image forming part including a photoreceptor and a developing unit. SOLUTION: As for the recording device, a supporting body which is constituted by aggregating and arranging image forming units 1Bk, 1C, 1M and 1Y with a developer hopper and a photoreceptor 9 integrally formed in a nearly circular state so that they may be attached/detached is rotated around a cylindrical shaft 31, and a mirror 5 for changing the optical path of exposure laser light and exposing the photoreceptor 9 is arranged in the inside of the shaft 31. Thus, the efficiency in storing each image forming unit is enhanced. Besides, the mirror 5 is arranged at the inside of the shaft 31, so that the occupancy volume is made smaller than that in the case of arranging the mirror 5 in a position other than the supporting body and the miniaturization of the device is attained.

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 general, in order to form a color image by electrophotography, a method of forming a color image by superposing toner images of yellow, magenta, cyan, and black on a transfer material has been adopted. As a method of forming this color image, a toner image of each color is sequentially formed on one photoconductor, and the transfer material wound around the transfer drum is rotated to repeatedly oppose the photoconductor, and the color of each color sequentially formed there is formed. A transfer drum system in which toner images are superimposed and transferred, and a plurality of image forming units are arranged side by side, and each color toner image is sequentially transferred to a transfer material conveyed by a belt or the like by passing through the position of each image forming unit. In general, a continuous overlapping method in which the sheets are overlapped is performed.

An example of the former using the transfer drum system is an example of a color image recording apparatus disclosed in Japanese Patent Application Laid-Open No. 1-252982.

FIG. 3 shows an outline of the overall configuration of this conventional example, and the configuration and operation will be briefly described below. In FIG. 3, reference numeral 101 denotes a photosensitive member, and
02, a developing unit 103, a transfer drum 104, and a cleaner 105 are provided. The developing unit 103 includes a Y developing unit 106 for forming a yellow toner image, an M developing unit 107 for magenta, and a C developing unit 10 for cyan.
8, a K developing device 109 for black, and the whole is rotated so that each developing device can be developed in a state where the developing device can face the photoconductor 101 sequentially.

During operation, the transfer drum 104 and the photoreceptor rotate at a constant speed in the direction of the arrow while facing each other.

First, when the operation is started, the photosensitive member 101 rotates in the direction of the arrow, and the surface thereof is uniformly charged by the charger 102.

Thereafter, the surface of the photoreceptor is irradiated with a laser beam 110 modulated by a signal for forming a first color yellow image.
To form a latent image. Further, this latent image is first developed in the yellow developing unit 106 facing the photoreceptor to form a yellow toner image. By the time the formed yellow toner image comes to a position facing the transfer drum 104, one sheet of the transfer material sent from the sheet feeding unit 111 has already been formed on the outer periphery of the transfer drum 104 with the claw part. The toner image is formed such that the yellow toner image on the photoreceptor is opposed to a predetermined position of the paper and is wrapped around the paper.

After the yellow toner image on the photoreceptor is transferred to the sheet by the operation of the transfer charger 113, the surface of the photoreceptor is cleaned by the cleaner 105 to prepare for the formation of the next color image. Subsequently, magenta, cyan, and black toner images are formed in the same manner. At that time, the developing unit 103 sets each developing unit that uses the color corresponding to the photoconductor 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.

Laser beam 110 for forming images of each color
Is performed at a timing such that the toner images of the respective colors on the photoreceptor and the toner images already transferred onto the paper on the transfer drum are aligned and faced with each other as they rotate. 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 sheet is peeled off from the transfer drum 104 by the peeling claws 114, the upper toner image is fixed by the fixing device 116 via the transport section 115, and the sheet is discharged out of the apparatus. The above is a brief description of the configuration and operation of the conventional example.

On the other hand, as an example of a color image forming apparatus using the continuous transfer system, there is Japanese Patent Application Laid-Open No. 1-250970. In this example, four image forming stations each including a photoreceptor and an optical scanning unit are arranged for forming images of four colors, and the paper conveyed to the belt passes under the respective photoreceptors and passes therethrough. 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, a method of superimposing toner images of respective colors sequentially formed on a photoreceptor on an intermediate transfer material is used. Is transferred to the transfer material at once as disclosed in JP-A-2-212867.

[0012]

Among the conventional examples described above, 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 photosensitive member, and the timing of the leading edge of the image is adjusted to match the mutual positions of the toner images of the respective colors when a color image is formed. 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 very complicated. Had become.

Further, rigid 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 method has an image forming position corresponding to the number of colors, and a sheet is required to pass through the sheets one after another. Therefore, a transfer drum is not necessary. A latent image forming means such as a laser optical system for forming a latent image is required corresponding to the number of colors, and the structure is very complicated and expensive at this portion. Furthermore, since there are a plurality of image forming positions, the relative positional relationship between the image forming units of each color greatly affects the color shift.

In particular, it is necessary for the latent image forming means to accurately position the latent image between respective colors.
As shown in the example of JP-A-70-70, there is a problem that a considerable device and a complicated configuration of an image exposure system as a latent image forming means are required.

Further, Japanese Patent Laid-Open No. 2-2 using an intermediate transfer material
In the example disclosed in Japanese Patent No. 12867, the shape of the photoconductor becomes large so that a toner image of each color can be formed on one photoconductor by each color developing unit. For example, a belt-shaped photoconductor is required. It becomes. In addition, there is a problem that the maintenance of the developing units and the photosensitive members of each color is also difficult. For example, each developing device requires image adjustment with the photoconductor at the time of maintenance, and when replacing the photoconductor, position adjustment with each developing device is required.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to eliminate the need for a complicated transfer drum and a complicated structure for aligning an image exposure system. An object of the present invention is to provide an excellent color image recording apparatus which can be accurately performed, has a simple configuration of a toner image forming section including a photoconductor and a developing device, is small in size, and has good maintainability.

[0018]

A color image recording apparatus according to the present invention has a rotating body in which a plurality of individual units each having a toner storage section and a photoreceptor are collectively arranged in a detachable manner in a substantially annular shape. Then, the image exposed and developed on the photoreceptor, a color image recording apparatus that transfers to a recording paper, the rotating body is configured to be rotatable around a cylindrical axis having an opening, The cylindrical shaft employs a configuration in which an optical path changing unit that changes an optical path of exposure laser light that enters through the opening and guides the light to the photoconductor is disposed inside.

The color image recording apparatus of the present invention is characterized in that the cylindrical shaft is fixed to the apparatus.

According to these constructions, by arranging the optical path changing means inside the cylindrical shaft, the occupied volume is reduced as compared with the case where the means is arranged at a place other than the rotating body, and the apparatus is downsized. Becomes possible.

The individual unit of the present invention is an individual unit used in the color image recording apparatus, and is configured to be detachable from the rotating body only above the apparatus and perpendicularly to the rotation axis, and , Formed in a substantially fan-shaped cross section,
It is characterized by the following. According to this configuration, since it is possible to attach and detach the rotator above the apparatus, it is possible to provide a user-friendly individual unit.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color image recording apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a color image recording apparatus according to an embodiment of the present invention. First, four fan-shaped image forming units 1Bk, 1C, 1M, and 1Y for each color of black, cyan, magenta, and yellow form a group of image forming units in the center, and are arranged in a ring as shown in the figure. ing. Each image forming unit is made of the same constituent members except for the developer contained therein, so that the image forming unit for black will be described for simplification of description, and the other colors will be omitted. Note that, for each color, the same portions are denoted by the same reference numerals, and when it is necessary to distinguish the configuration of each color, a character indicating each color is denoted by the reference numeral. FIG. 2 shows a black image forming unit 1.
Bk is shown in detail.

In FIG. 2, reference numeral 9 denotes an organic photoreceptor in which phthalocyanine is dispersed in a polycarbonate binder resin;
0 is a non-rotating magnet fixed coaxially with the photosensitive member 9;
Denotes a charging roller for negatively charging the photoconductor, 13 denotes a laser beam scanning light, and 14 denotes a developer hopper.

In the developer hopper 14, a two-component developer 2 is prepared by mixing a ferrite carrier 24Bk having a particle diameter of 50 μm, the surface of which is coated with a silicone resin, and a toner 25Bk.
6Bk was added and attached to the surface of the photoreceptor 9 by magnetic force.
The toner used is obtained by dispersing a pigment in a polyester resin and further adding an additive.

Reference numeral 17 denotes a rotatable collecting electrode roller made of aluminum, 16 denotes a non-rotating magnet coaxially fixed inside, 18 denotes an AC high-voltage power supply for applying a voltage to the collecting electrode roller, and 19 denotes a power supply on the collecting electrode roller. A scraper made of polyester film that scrapes toner. Photoconductor 9
Has a diameter of 30 mm and is rotated in the direction of the arrow at a peripheral speed of 60 mm / s. The collection electrode roller 17 has a diameter of 16 mm and a peripheral speed of 60 mm / s.
It was rotated in the direction of the arrow at mm / s.

Reference numeral 27 denotes a cleaner for cleaning the toner remaining on the surface of the photosensitive member after the transfer. The operation of the image forming unit configured as described above will be described below with reference to FIG. The photoconductor 9 was charged to −500 V by the charging roller 11. The photosensitive member 9 was irradiated with laser beam scanning light 13 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -100V.

On the surface of the photosensitive member 9, a two-component developer 26
Bk was deposited by magnetic force in the developer hopper 14.
Next, the surface of the photoconductor 9 was passed in front of the collection electrode roller 17. When the photosensitive member 9 passes through the uncharged area, the electrode roller 17
750 V0-p (1.5 kV peak-to-peak) on which a 0 V DC voltage was superimposed was applied by an AC high-voltage power supply 18 at a frequency of 1 kHz. Then, -5
When passing through the surface of the photoreceptor 9 charged with the electrostatic latent image and charged to 00 V, the electrode roller 17 is superposed with a DC voltage of -350 V by an AC high-voltage power supply 18 to 750 V0-p (peak-to-peak 1. 5 kV) AC voltage (frequency 1.5 kHz) was applied. Then, the toner adhered to the carrier and the charged portion on the photoconductor 9 was collected by the electrode roller 17, and a negative-positive toner image was left only on the image portion on the photoconductor 9. Electrode roller 17 rotating in the direction of the arrow
The carrier and the toner adhered to the surface were scraped off by a scraper 19, returned to the developer hopper 14 again, and used for the next image formation.

Thus, a black toner image is obtained on the photoreceptor 9. The other developing units 1C, 1M, and 1Y other than black have the same configuration and operate.

Referring again to FIG. 1, the configuration of the printer unit will be described. Image forming unit 1B arranged in an annular shape
k, 1C, 1M, and 1Y are supported by a support (not shown), and are driven by a moving motor 30 as a moving unit as a whole, and are rotatable about a cylindrical fixed and non-rotating shaft 31. It has become. Each image forming unit can be sequentially located at an image forming position 50 facing a first transfer roller 33 that supports an intermediate transfer belt 32 described later. The image forming position 50 is also an exposure position by the signal light 13.

Reference numeral 3 denotes a laser exposure device, which is a signal light 13 of a laser beam modulated by a signal input to a printer unit.
Which is caused by the image forming units 1M and 1Y of FIG.
An image forming unit which passes through the optical path formed between the mirrors and is fixed to the mirror 5 fixed inside the shaft 31 through the windows 4a and 4b opened in a part of the shaft 31, is reflected and is at the image forming position 50 Of the photosensitive member 9 to form a latent image. In the state of FIG. 1, it acts on the image forming unit 1Bk for black.

Here, since the optical path to the mirror 5 is along the wall surface of the image forming units on both sides, there is almost no portion wasted as the area occupied by the image forming unit group.
Further, since the mirror 5 is provided at the center of the image forming unit group, it can be constituted by only one fixed mirror, and has a simple and highly reliable structure for alignment and the like.

Reference numeral 32 denotes an intermediate transfer belt having a thickness of 100 μm.
Is wound around a first transfer roller 33 and a stainless steel roller 34, which are formed of an endless belt-shaped film made of semiconductive urethane as a base material, and around which are formed a urethane foam with a low resistance treatment, and move in the direction of the arrow. It is possible. Here, the intermediate transfer belt 32 has a circumference of A
The length is set slightly longer than the length of the four sheets in the longitudinal direction. The first transfer roller 33 is lightly pressed against the photoconductor 9 via the intermediate transfer belt 32. A second transfer roller 35 having the same configuration as the first transfer roller 33 is lightly pressed against the roller 34 via the intermediate transfer belt 32 so as to be driven and rotatable.

Intermediate transfer belt 32 and second transfer roller 35
The paper feed sections 36a and 36b
The paper transport path is formed so that paper is sent from the printer.

Reference numeral 40 denotes a belt cleaner section including a belt cleaner for cleaning the intermediate transfer belt.

A fixing unit 44 fixes the toner image on the sheet after the transfer, and a discharge roller 45 discharges the sheet after the fixing.

The above is the description of the main configuration of the color image recording apparatus of the present invention. Next, the operation of this apparatus when forming a color image will be described.

First, the image forming unit is at the position as shown in FIG. 1, and the image forming unit 1Bk for black is at the image forming position 50 as shown in the figure. It also faces the first transfer roller 33. The black signal light is input to the image forming unit 1Bk by the laser exposure device 3, and an image is formed with black toner. At this time, the image forming speed of the image forming unit 1Bk (equal to the peripheral speed of the photoconductor)
And the moving speed of the intermediate transfer belt are set to be the same. At the same time as the image is formed, the black toner image is transferred to the intermediate transfer belt by the action of the first transfer roller 33. Immediately after all the black toner images have been transferred,
The entire image forming unit group 1Bk, 1C, 1M, 1Y is driven by the moving motor 30 to rotate integrally in the direction of the arrow in FIG.
Stops at a position where it has reached the vicinity 50 of the image forming position. During this time,
Since the portion of the developer hopper 14 (see FIG. 2) other than the photoconductor of the image forming unit is located inside the rotation arc at the tip of the photoconductor, the intermediate transfer belt does not contact the image forming unit.

After the image forming unit 1C arrives at the image forming position 50, the laser exposure apparatus inputs signal light to the image forming unit 1C with a cyan signal as before, and forms and transfers a cyan toner image. Will be At this time, the timing of writing the cyan signal light is controlled such that the intermediate transfer belt makes one rotation, and the next cyan toner image is positionally matched with the previously transferred black toner image. During this time, the second
The transfer roller 35 and the belt cleaner 40 are slightly separated from the intermediate transfer belt, and do not act on the toner image thereon.

The same operation as described above is performed for magenta and yellow, and four color toner images are superimposed on the intermediate transfer belt so as to be aligned with each other to form a color image. After the transfer of the final yellow toner image, the toner images of the four colors are collectively transferred to the sheet sent from the sheet feeding unit 36a or 36b at the same time by the operation of the second transfer roller 35. The toner image transferred to the paper is fixed by the fixing device 44. Thereafter, the sheet is discharged out of the apparatus via a discharge roller 45. The transfer residual toner remaining on the intermediate transfer belt is cleaned by the operation of the belt cleaner unit 40 to prepare for the next image formation.

Next, the operation in the monochrome mode will be described. In the monochrome mode, first, an image forming unit of a predetermined color is moved to an image forming position. Next, image formation of a predetermined color and transfer to the intermediate transfer belt are performed in the same manner as before, and this transfer is continued as it is, and transfer to the sheet sent from the sheet feeding unit by the next second transfer roller is performed. I will do it.

Next, the maintenance of the apparatus will be described. It is assumed that the developer of a specific color is no longer consumed and maintenance is performed. First, the image forming unit group is rotated by the action of the moving motor 30,
The image forming unit of the target color is moved to the upper position (the position of the image forming unit 1C in FIG. 1). Then, the cover 46 located at the upper part of the apparatus main body is opened, and only the noted image forming unit is taken out of the apparatus from the cover 46. Next, a new image forming unit of the color adjusted in advance as an image forming unit is mounted.

Therefore, after mounting, image formation can be started without any adjustment. The above is the description of the configuration and operation of the embodiment.

According to the present invention, since the images of each color are formed at the same image forming position without using a transfer drum having a complicated structure, accurate color registration can be performed with a simple structure. In addition, the image forming means is completed independently as one image forming means for each color, so that the configuration is simple, and excellent in maintainability such that the image forming means can be replaced for each color. Becomes

Therefore, in this configuration, since each image forming unit including the photoconductor can be independently adjusted outside, it is possible to easily replace, for example, a unit already adjusted at the time of shipment from a factory.

Furthermore, in the present configuration, even when a color image is continuously formed, each photosensitive member is inactive every time while forming another color, so that a stable image without electrostatic fatigue can be obtained. can get.

In the above embodiment, a specific structure is used as the structure of the image forming unit. However, even in the case of an image forming unit having a structure using a conventional developing method,
The essence and effect of the present invention do not change.

[0048]

As described above, the present invention does not use a transfer drum having a complicated structure, has a simple structure, and forms images of all colors at the same image forming position.
Accurate color registration can be performed with a simple configuration. In addition, since the image forming unit is completed independently as one image forming unit for each color, the configuration is simple,
In addition, maintenance properties such as replacement of an image forming unit adjusted in advance for each color can be improved.

Further, the configuration for guiding the light for exposure into the image forming unit group allows the image forming unit group to be simple, occupy a small volume, and be downsized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a color image recording apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an image forming unit used in a color image recording apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional color image recording apparatus.

[Explanation of symbols]

 Reference Signs List 3 laser exposure device 5 mirror 1Bk, 1C, 1M, 1Y image forming unit 9 photoconductor 32 intermediate transfer belt 33 first transfer roller 35 second transfer roller

Claims (3)

[Claims] An image formed by exposing and developing an image on the photosensitive member, the rotating body including a plurality of individual units each having a toner storage portion and a photosensitive member, which are collectively arranged in a ring shape in a detachable manner. A color image recording apparatus that transfers the image to recording paper, wherein the rotating body is configured to be rotatable around a cylindrical axis having an opening, and the cylindrical axis is inserted through the opening. A color image recording apparatus, comprising: an optical path changing unit that changes an optical path of an exposure laser beam that emits light and guides the light to the photoconductor. 2. The color image recording apparatus according to claim 1, wherein the cylindrical shaft is fixed to the apparatus. 3. An individual unit for use in a color image recording apparatus according to claim 1 or 2, wherein said unit is detachable from said rotating body only above the apparatus and perpendicularly to said rotation axis. An individual unit characterized by being formed in a substantially fan-shaped cross section.