JPH03132671A - Color image forming device - Google Patents

Abstract

PURPOSE:To stably obtain a color image by forming a belt shape image forming body in a unit so that it can be inserted to an extracted from an upper enclosure, and providing a shutter member which protects the plane of the image forming body exposed when the upper enclosure is opened/closed or the unit is inserted or extracted. CONSTITUTION:The belt shape image forming body 1 and the upper enclosure in which the unit containing a cleaning device, etc., is assembled so that it can be inserted and extracted are provided on a device main body so that they can be released. Furthermore, a protective plate 22 having plural aperture parts is provided on the lower plane of the belt shape image forming body 1, and the shutter member 23 opened/closed by the movement of the aperture part in a lateral direction is provided on the lower plane of the protective plate 22. When the upper cabinet 20 is opened or the image forming unit is inserted/extracted, the shutter member 23 functions against the tensile force of a spring for rewinding, and is set after being moved to the position of a stopper in a direction of arrow head, then, all the aperture parts for protection are shielded. Thereby, it is possible to prevent the fatigue and deterioration of the image forming body occurring, and the color image can be stably obtained extending over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus such as a color printer or a color copying machine that forms color images by an electrophotographic method using a belt-like image forming member.

[Conventional technology]

Conventionally, a drum-shaped image forming body has been used in an electrophotographic image forming apparatus. However, the drum-shaped image forming body requires sophisticated processing techniques, resulting in poor processing yield and high cost. Therefore, in recent years, an image forming apparatus using a belt-like image forming body, which is made by coating or vapor-depositing a photoconductive material on a visible belt and is easy to process and inexpensive, has been studied.
For example, Japanese Patent Application Laid-Open No. 129678/1983 proposes a monochrome laser printer using the belt-like image forming body. In this printer, the shape of the belt-shaped image forming body is determined by being stretched between rotating rollers including a drive roller, and there is an advantage that space can be used effectively and compactness can be achieved. Further, in the printer, the outer belt-like image forming body having a talam shell structure is made into a unit and can be inserted into and removed from the main body of the apparatus, making it easy to remove jams and replace parts.

However, in the printer described in the above-mentioned publication, no measures are taken to protect the image forming body when the clamshell is opened or when the unit is inserted or removed.

Incidentally, in the copying industry, there is an increasing demand for color images with a larger amount of information in place of monochrome images.

Therefore, a color copying machine using the belt-shaped image forming body has been developed as, for example, the Sharp full color copying machine CX-7500, and is commercially available. The color copying machine is of an analog type, and includes a belt-shaped image forming body, a plurality of developing devices arranged in parallel above the image forming body, and an electric control system in an apparatus main body including a paper feeding and conveying system. The upper housing is provided to be openable. Furthermore, in image formation by the color copying machine, toner images of each color are sequentially formed on the image forming body by multiple rotations of the belt-like image forming body. The toner images of each color are superimposed on the transfer belt to form a color toner image. This color toner image is transferred onto transfer paper and fixed to form a color image.

C Problems to be Solved by the Invention] However, in the color copying machine, as described above, the upper housing, which is open to the apparatus main body, includes a belt-shaped image forming body, a plurality of developing units, and an analog control system. etc., the operation of opening the upper casing is heavy and difficult.

I; Since no measures have been taken to protect the surface of the image forming body that is exposed when the upper housing is opened, there is a problem that the image forming body is susceptible to fatigue deterioration due to light, dust adhesion, damage, etc. be.

During external image formation, the toner images of each color formed by multiple rotations of the image forming body are superimposed on the intermediate transfer belt, which causes problems such as poor superposition accuracy and the inability to obtain color images with good resolution. There is.

By the way, regarding the problem of protecting the exposed surface of the image forming body, for example, Japanese Patent Laid-Open Nos. 59-34546 and 59
-61865, Japanese Patent Application Laid-Open No. 59-61860, etc. However, the techniques described in these publications all relate to copying machines that form monochrome images in an analog manner using an image forming drum.

Regarding the image forming method of a color image, for example, Japanese Patent Application Laid-Open No. 60-75850, Japanese Patent Application Laid-Open No. 60-76766, etc., a color toner image is formed by superimposing toner images of each color on an image forming body. A technique has been proposed in which the color toner image is transferred all at once onto a transfer paper and fixed to form a color image. According to this technique, since the toner images of each color are directly superimposed on the image forming body, there is an advantage that a color image with high resolution can be obtained without color shift. However, all of the techniques described in the above-mentioned publications perform image formation using an image forming drum, and do not disclose protection of the drum surface of the image forming body.

(Object of the Invention) The object of the present invention is to provide a color image forming apparatus in which an upper housing is openable to the main body of the apparatus, and a unit including a belt-shaped image forming member is removable from the upper housing. Provided is a color image forming device that stably supplies high-performance color images by effectively protecting the surface of the image forming body that is exposed when the upper housing is opened or when the unit is inserted or removed. It's about doing.

[Structure and operation of the invention]

The above object is to provide an image forming means including a belt-like image forming body stretched between a plurality of rotating rollers, a charger, an exposing means, and a plurality of developing devices arranged in parallel around the periphery of the image forming body. and a color image forming apparatus comprising an apparatus main body and an upper housing that is openable to the apparatus main body, wherein the belt-shaped image forming body is removable from the upper housing. The unit is configured as a unit, and the unit is characterized by having a shutter member that opens and closes and protects the surface of the image forming body exposed when the upper housing is opened and closed or when the unit is inserted and removed by moving in the lateral direction. This is accomplished by a color image forming device.

The color image forming apparatus of the present invention includes yellow (Y), magenta (M), cyan (C), and black (BK) developing devices arranged in parallel, a paper feed conveyance system, a transfer pole, a charging electrode,
An upper casing in which a unit including a belt-shaped image forming body, a cleaning device, etc. is removably installed is provided in an openable manner to the main body of the device, which includes a writing device using a laser beam, an LED light, etc. ing.

That is, since a plurality of heavy developing units are arranged in parallel below the image forming body on the apparatus main body side, the upper housing can be easily opened, toner contamination inside the apparatus is reduced, and the entire apparatus is The configuration has been stabilized.

The above configuration is for a color printer, but when a color copying machine is used, a color scanner is usually incorporated into the upper housing.

Next, the unit including the belt-like image forming body is provided with a protection plate having a plurality of openings on the bottom surface of the belt-like image forming body, as shown in FIG. A sliding member is provided which opens and closes the opening by moving it in the lateral direction. In FIG. 1, for the sake of understanding, (A) a belt-shaped image forming unit, (B) a protective plate, (C) a shutter member, and (D) various image forming members are shown separated from each other.

The protection plate shown in FIG. 1(B) is located within the image forming unit shown in FIG. C) Charger and exposure apertures Y, M, and C.

Openings are provided at positions facing each of the BK developing rolls.

These openings are also in the unit and have openings of the same size at the corresponding positions as shown in FIG. 1(C).
The shutter member is opened and closed by moving in the lateral direction.

The shutter member according to the present invention opens and closes a large number of openings of the protection plate at once by a slight movement along the plane l2 of the protection plate, and as a result, the shutter members are arranged over a wide area of the image forming body. It has the function of protecting many exposed surfaces with a simple mechanism.

That is, as shown in FIG. 1(C), when the upper housing is opened or when the image forming unit is inserted or removed, the shutter member incorporated in the unit is rotated by the rotation of the winding handle. , it is moved in the direction of the arrow to the stopper position against the tension of the unwinding spring, and is set at that position by the locking member. In this case, the opening of the shutter member is moved from the position indicated by the dotted line to the position indicated by the solid line, so that all the protective openings are covered. Next, the upper case is closed, and when the unit is loaded, the lock is released and the shutter member is returned to the reference position (the position indicated by the dotted line) by the tension of the unwinding spring, and each of the shutter members is The aperture and the aperture of the protection plate match to enable image formation.

The means for opening and closing the shutter member is preferably opened and closed by manually rotating an opening and closing handle, or it is preferably opened and closed mechanically in conjunction with the opening and closing of the upper casing.

and motor drive outside of said manual or automatic mechanical means;
It may be opened and closed by solenoid drive or the like. When the jack member is opened and closed, the shutter member moves close to the surface of the developing roll and is therefore contaminated with developer. Therefore, the shutter member is not moved in the lateral direction when the upper housing is in close contact with the main body of the apparatus, but is performed during the separation process. Therefore, timing selection is important for manual operation.

With the above configuration, the exposure of the belt-shaped image forming body when it is inserted and removed is shielded and protected, and the image forming body is prevented from deteriorating due to fatigue, damage, and contamination by dust, and high-quality images can be stably supplied for a long time. It becomes like this.

The developing units installed in the lower housing are arranged in parallel on the lower surface of the belt-shaped image forming body with the developing surfaces facing upward, and are preferably integrated with each other by sharing a part of the wall surface with respect to the main body of the apparatus. Preferably, it is removable. This configuration has the advantage that toner contamination and color mixing between the developing units is reduced, and the center of gravity of the entire apparatus is relatively low, resulting in a stable arrangement.

In order to form a color image using the color image forming apparatus of the present invention, a color information reading device is used to read the color information of a color document for each color, and the obtained color information is converted into an electrical signal. Modulate laser light or LED light. The resulting modulated light is exposed onto an image forming body that rotates for each color signal to form an electrostatic latent image, which is developed to form a color toner image. The above steps are repeated for the number of color signals to form a color toner image formed by overlapping toner images of each color, and this is transferred and fixed all at once onto a transfer material to form a color image. The above explanation is about a method for binding a color copying machine, but it may also be a printer that forms a color image using an external error signal from a CPU or the like without using the color information reading device. In addition, a charging device and an exposure device for each color are installed in each developing device, and a color toner image is formed by overlapping toner images of each color with one rotation of the image forming body, and the toner images are transferred all at once onto a transfer material. - It may be fixed to form a color image.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto.

(Embodiment 1) FIGS. 2 and 3 are diagrams illustrating the configuration of a color printer of this embodiment.

In FIG. 2, ■ is a visible photoreceptor belt that is a belt-like image forming member, and the photoreceptor belt 1 is connected to rotating rollers 2 and 3.
Rotating roller 2 consisting of a rubber roller and installed between
It is transported clockwise by the drive of.

Reference numeral 4 denotes a guide member fixed to the main body of the apparatus so as to be inscribed in the photoreceptor belt l, and the photoreceptor belt l is brought into a tensioned state by the upward mechanical action of the tension roller 5, so that its inner peripheral surface is rubbed against the guide member 4.

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt l are always maintained at a constant position relative to the surface of the guide member 4 even during conveyance, making it possible to form a stable image forming surface.

Reference numeral 6 denotes a scorotron charger as a charging means, 7 a laser writing system unit as an image exposure means, and 8 to 11 a plurality of developing means, that is, developing devices each containing a developer of a specific color, each of which forms an image. The means is disposed facing the outer peripheral surface of the photoreceptor belt l with the guide member 4 on the back side.

Each developer 8.9.10.11 is Y (yellow) M (
Each developing sleeve 8A accommodates each developer (magenta), C (cyan), and BK (black), and maintains a predetermined gap with the photoreceptor belt 1.

9A, IOA, and IIA, and has a function of developing a latent image on the photoreceptor belt 1 by a non-contact development method.

Unlike contact development, this non-contact development has the advantage of not interfering with the movement of the photoreceptor belt.

In color image formation by the color printer of this embodiment,
A color signal from an external device such as a CPU is input to the laser writing system unit 7, and in the laser writing system unit 7, a laser beam oscillated by the semiconductor laser device 30 is rotated by a drive motor 7A. It is rotated and scanned by a polygon mirror 7B, passes through an fθ lens 7C, has its optical path bent by mirrors 7D and 7E, is charged in advance by a charger 6 serving as a charging means, and is projected onto the circumferential surface of a photoreceptor bell). A latent image is formed.

On the other hand, when the scanning starts, the beam is detected by the index sensor, the modulation of the beam by the first color signal is started, and the modulated beam is transferred to the photoreceptor bell l-1.
scan the circumferential surface of the Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt l-1 by main scanning by the laser beam and sub-scanning by the conveyance of the photoreceptor belt l. This latent image is developed by a developing device 8 loaded with yellow (Y) toner (developing medium) in the developing means.
A toner image is formed on the belt surface. The obtained toner image, while being held on the belt surface, passes under a cleaning device 13, which is a cleaning means, which is separated from the peripheral surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photoreceptor belt l is charged again by the charger 6, and then the second color signal outputted from the signal processing section is input to the writing system unit 7, and the second color signal is inputted to the writing system unit 7, and the second color signal is inputted to the writing system unit 7. In the same manner, writing is performed on the drum surface to form a latent image. The latent image is developed by a developer 9 loaded with magenta (M) toner as a second color.

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

A developing device 10 has cyan (C) toner, and forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing section.

Further, numeral 11 denotes a developing device having black toner, which forms a black toner image by superimposing it on the drum surface using the same process. A direct current or even an alternating current bias is applied to each sleeve of each of these developing devices 8°9. Development is performed without contacting the belt l. As for the development, non-contact development using a component (1) developer can also be used.

The color toner image thus formed on the circumferential surface of the photoreceptor belt l is transferred to a transfer material fed from the paper feed cassette 14 via the paper feed guide 15 at the transfer section.

That is, the top layer of the transfer material housed in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and is transferred via the timing roller 17 in synchronization with the image formation on the photoreceptor belt l. is supplied to the vessel 12.

The transfer material, which has undergone the transfer and charge removal of the color toner image, is transferred to the photoreceptor belt 1 which suddenly changes direction along the rotating roller 2.
The paper is reliably separated and directed upward, and after the image is fused by the fixing roller 18, it is discharged onto the tray 20 via the paper discharge rollers 19A and 19B.

On the other hand, the photoreceptor belt l that has completed the transfer to the transfer material continues to be conveyed to the blade 13A and the toner conveying roller 13B.
The remaining toner is removed in the cleaning device 13 with the blade 13A pressed against the blade 13A, and after that, the blade 13A is separated again, and a little later, the toner conveying roller 13B smoothes out the toner accumulated on the tip of the blade 13A. , the toner conveying roller 13B is separated and a new image forming process begins.

The color image forming apparatus has a cram-n-el structure in which the upper casing can be opened by rotating the upper casing clockwise around the rotation shaft 21, and the photoreceptor belt 1 and the cleaning device 13 are attached to the unit on the upper casing side. Each developing device, laser writing system unit 7, fixing roller 1
8 and the like are housed together with the paper feed cassette 14 in the lower housing side.

A protection plate 22 having the structure shown in FIG. 1(B) is provided in the unit I-K close to the lower surface of the photoreceptor belt 1, and the protection plate 22 is provided with an image forming member. Y, M, C
, BK, etc. developing rolls 8A, 9A, IOA, II
The opening for A and charging exposure is provided in the shape of a square hole.

The opening of the protection plate 22 is opened and closed by a shutter member 23 that moves along the lower surface of the protection plate under the action of a solenoid 30.

The shunter member is provided with a square hole-shaped opening as shown in FIG. 1(C) at a position corresponding to the opening of the protection plate, and the right end of the shutter member is It is fixed to the roll 23A and biased in the unwinding direction by the action of a spring 23C. Before the upper case reaches the closed position shown in FIG. 2 from the position shown in FIG. 3, the shunter member 23 is wound up by the winding roll 23A by the action of the spring 23C when the solenoid is turned off, and the protective plate opening is opened. The upper casing is brought into contact with the opening of the first member, and the upper casing is brought into close contact with the main body of the apparatus, after which image formation is possible. Further, when the upper housing is opened from the main body of the apparatus, the solenoid is turned on for a predetermined period of time, and the shutter member 23 is moved to the left in the drawing by the width of the opening, and each opening of the protection plate is connected to the opening of the one member. The surface of the photoreceptor is protected by being shielded by other areas.

As described above, in the color printer of this embodiment, the devices are assembled in a stable arrangement from the front, and the Cram-n-El structure makes it easy to remove jams and replace parts. Since the surface of the image forming apparatus was protected by the protective plate and the coating material, fatigue deterioration of the image forming body was extremely small, and stable color images could be obtained even after repeated use over a long period of time.

In the above explanation, the movement of the shutter member as the upper housing is opened and closed has been explained, but the same is true when inserting and removing the shutter member into and out of the photoconductor unit. Opening and closing can be performed by moving the members.

(Embodiment 2) FIG. 5 is a sectional view of a main part of a color printer explaining this embodiment, and the differences are as follows.

■ Chargers 506, 509, 512, 515 and LED exposure devices 5 are installed on the bottom surface of the photoreceptor belt 501 for each of the Y, M, C, and BK developing devices 508, 511, 514, and 517, respectively.
07, 510, 513, 516 are provided, and the image forming body 5
By 0101 rotation, 4 of Y, M, C, BK are formed on the photoreceptor.
Color toner images are formed one on top of the other, and these four color toner images are collectively transferred onto transfer paper and fixed to form a color image.

■For this reason, a protective plate 52 is placed on the underside of the photoreceptor belt.
2 and the shutter member 523, a total of eight openings are arranged at approximately constant intervals, four openings at positions facing each of the developing units, and four openings at positions facing the four sets of chargers and exposure units. .

■When the upper casing is closed, the winding roll 52
In 3D, the bar 524 fixed to the roll shaft hits the protrusion 525 on the device main body side and is pushed upward to the position 524, so the shutter member is moved to the left in the drawing, and the photoreceptor is charged. , exposure, development, etc., are opened to enable image formation.

Further, when the upper case is opened, the original roll 52
3A is actuated to wind back the shutter member by the tension of the spring 523C, and while moving the bar 524 of the winding roll 523D to the position 524', the shutter member is moved to the right in the drawing, thereby shielding each of the image forming surfaces. be done.

Except for the above items ■ to ■, the configuration is almost the same, and the external Y, M,
Each color signal of C and BK is L E D 507, 510, 5
The light source light having an angle of 13°516 was modulated, and a color toner image was formed by one rotation of the photoreceptor using the resulting modulated light of each color. This color toner image was fixed with a hot roll as in Example 1 to form a color image.

Further, protection of the photoreceptor was ensured by opening and closing the protection plate 522 and shutter member 523 as in Example 1, and stable color images were obtained without fatigue deterioration even when color images were repeatedly formed.

〔Effect of the invention〕

As is clear from the above description, according to the color image forming apparatus of the present invention, the surfaces of the belt-shaped image forming body exposed at a plurality of locations when the upper housing is opened or when the image forming body unit is inserted or removed can be easily exposed. Protected by the operation of one shutter member of the structure,
Therefore, effects such as preventing fatigue deterioration of the image forming body and ensuring durability during repeated use are achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating the arrangement of a protection plate and a shutter member, and FIGS. 2 to 4 are sectional views of a color printer illustrating an embodiment. 1.501...Image forming belt (photoreceptor belt)2.
3... Rotating roller 4.504... Guide member 7
. . . Laser writing system unit 6. 506, 509, 512, 515 . . . Charger 8.
9.10.11,508,511,514,517...
・Developer 22.522...Protection plate 23,523
... Nyatta part 23A, 523A... Original winding roll 23B, 523D... Winding up roll 30...
・Solenoids 507, 510, 513, 516...LED exposure device 524...Bar 525...Protrusion member K...Image forming unit

Claims (5)

[Claims] (1) A belt-shaped image forming body stretched between a plurality of rotating rollers, and an image forming means including a charger, an exposure means, and a plurality of developing devices arranged in parallel around the periphery of the image forming body. It consists of
In a color image forming apparatus comprising an apparatus main body and an upper housing that is openable to the apparatus main body, the belt-shaped image forming body has a unit configuration that can be inserted into and removed from the upper housing. A color image forming apparatus characterized in that the unit has a shutter member that opens and closes by moving in a lateral direction to protect a surface of the image forming body that is exposed when the upper housing is opened and closed or when the unit is inserted and removed. (2) A color toner image is formed by overlapping each color toner image on the image forming body by multiple operations of the image forming means, and the color toner image is transferred all at once onto a transfer material. The color image forming apparatus according to item 1. (3) A color image forming apparatus according to claim 1 or 2, wherein the exposure means uses light modulated by an electrical signal. (4) The color image forming apparatus according to any one of claims 1 to 3, wherein the plurality of developing devices are arranged below the image forming body. (5) The unit including the image forming body has a protective plate disposed on the lower surface of the image forming body and having a plurality of openings, and the shutter member has a protective plate necessary for opening and closing the openings of the protective plate. A color image forming apparatus according to any one of claims 1 to 4, which is moved in width.