JPH06194886A - Color image forming device - Google Patents

Abstract

PURPOSE:To prevent an electrostatic charger and a laser write system unit provided in a color image forming device from being contaminated by toner and to miniaturize the device. CONSTITUTION:A process cartridge 21 obtained by integrating a photo-sensitive belt 1 which is wound and stretched over respective turning rollers 2 and 3, respective developing devices 8, 9, 10 and 11 which are arranged under the belt 1 and house the developer of respective colors and a cleaning device 13 is constituted to be drawn out. The electrostatic charger 6 and the laser write system unit 7 are disposed above the cartridge 21, and the cartridge 21 can be drawn out to a front side in figure(or an opposite side thereto). Toner hoppers 8B, 9B, 10B and 11B of the respective colors interfere in the drawing- out direction of the cartridge 21 and respectively loaded in the respective developing devices 8 or 11. Therefore, the process cartridge 21 is drawn out after the toner hopper 8B or 11B is drawn out first.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measure for preventing toner stains caused when a process cartridge provided in an electrophotographic color image forming apparatus having a belt-shaped image forming body is attached or detached.

[0002]

2. Description of the Related Art Conventionally, a color image forming apparatus in which a belt-shaped image forming body is stretched substantially horizontally and a plurality of developing devices are arranged in parallel on the lower surface of the image forming body is disclosed in, for example, JP-A-61-151560. And are known. According to the color image forming apparatus described in the above publication, the image carrier belt is 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 opposite to each other, the charger, the exposure section by the laser writing system, and the yellow disposed at the above-described position in the order of forming an image. , A magenta, cyan, and black developer, respectively, and a transfer provided at a predetermined interval so as to face the curved surface of the image carrier belt wound around one rotating roller. A fixing device and a fixing device are provided above the transfer device and the transfer device, respectively. A cleaning device is provided adjacent to the charging device, facing the curved surface of the image carrier belt wound around the other rotating roller and having a predetermined distance.

The color image forming apparatus having the above-mentioned structure records color images one after another on recording paper which is intermittently conveyed.

[0004]

The belt-shaped image forming body includes an integrated process cartridge in which a plurality of developing devices, a cleaning device, and a waste toner box are integrated, and a plurality of developing device units from the integrated process cartridge. For example, a split type process cartridge in which the waste toner box is divided and only the cleaning device is integrated.
The structure according to the type is general.

In either case, it is necessary to prevent the charging device and the image exposure device provided in the image forming apparatus from being contaminated by toner scattering, or the toner spilling out when the process cartridge is pulled out to prevent the inside of the apparatus from being contaminated.

Particularly, it is preferable that the charging device, the image exposure device, and the like, which are difficult to get dirty, are arranged above the process cartridge, and the developing device and the cleaning device, which are contamination sources, are arranged below.

However, conventionally, it cannot be said that the mechanical units such as the charger, the image exposure device, the developing device, and the cleaning device described above are properly arranged for such toner stains.

In particular, if the developing device and the cleaning device are arranged above or on the side surface of the process cartridge, the toner will be spilled out when the process cartridge is pulled out and the inside of the device will be contaminated.

Focusing on this point, the present invention arranges, for example, a charging device and an image exposure device which are not contaminated with respect to the belt-shaped image forming body, and a developing device and a cleaning device which are sources of toner contamination are arranged below. It is an object of the present invention to provide a more compact image forming apparatus while preventing toner stains.

[0010]

The present invention provides the following a, b,
It is achieved by either c or d.

(A) A color image forming apparatus having at least a charging device, an image exposure device, a plurality of developing devices, a cleaning device, and a transfer device for a stretched belt-shaped image forming body, A charging device, an image exposure device, a plurality of developing devices and a cleaning device, and a transfer device are arranged in this order with respect to the moving direction of the image forming body, and the charging device and the image exposing device are arranged above the image forming body and a plurality of developing devices are provided. A color image forming apparatus having a cleaning device disposed below.

(B) A belt-shaped image forming member stretched,
In a process cartridge in which a plurality of developing devices and a cleaning device are separated from each other or integrated with each other and can be attached to and detached from an image forming apparatus, a toner hopper arranged in parallel with the developing device interferes with the attachment and detachment of the process cartridge. A color image forming apparatus, wherein a process cartridge can be attached and detached by retracting the toner hopper attached to the process cartridge. (C) In the color image forming apparatus, the process cartridge is pulled out in the rotation axis direction of the image forming body stretched around a plurality of rotation axes in (b).

In (d) b, the color image forming apparatus is characterized in that the process cartridge is pulled out in a moving direction of the image forming body stretched around a plurality of rotation shafts.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is a side sectional view showing the structure of a color image forming apparatus of FIG. 1, a front view of FIG. 2, a schematic view of the same upper surface of FIG. 3 and an image forming system of FIG. The block diagram of FIG.

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

1 and 2 show an image forming apparatus 25 of the present invention. In FIG. 1, reference numeral 1 is a flexible photosensitive belt which is a belt-shaped image forming body, and the photosensitive belt 1 is a rotating roller 2 and It is installed between 3 and is rotated in the counterclockwise direction indicated by the arrow by driving the rotating roller 2.

Reference numeral 4 denotes a guide member fixed to the main body of the apparatus so as to be inscribed in the photoconductor belt 1. The photoconductor belt 1 is stretched by the action of the tension roller 5 so that its inner peripheral surface is The guide member 4 is rubbed. It should be noted that the guide member 4 is provided with a concave portion in an area unnecessary for image formation to reduce resistance due to rubbing. Of course, this recess may be omitted if the rubbing resistance is low. Further, a low friction member such as Teflon is provided on either surface of the photoconductor belt 1 or the guide member 4 for the purpose of reducing the sliding resistance between the photoconductor belt 1 or the guide member 4, or is composed of the above low friction member. Preferably.

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 rotation, so that a stable image forming surface can be formed. There is.

On the upper surface side of the stretched photoreceptor belt 1, a scorotron charger 6 which is a charging means and a laser writing system unit 7 which is an image exposure means are arranged in this order from the right side in the rotating direction of the photoreceptor belt 1. And the developing devices 8, 9, 10, 11 and the cleaning device 13 are arranged in this order from the left side on the lower surface side.

Further, the cleaning device 13 and each developing device 8,
A waste toner box 13C is arranged below 9, 10, and 11.

Further, below the waste toner box 13C, a paper feed cassette 14 is removably loaded.

Each of the developing devices 8 to 11 is a developing device which is a plurality of developing means containing a developer of a specific color, and these image forming means are located at positions facing the guide member 4 of the photosensitive belt 1. It is arranged. Then, in order to maintain the gap without hindering the movement of the photoconductor belt 1, the guide member 4 is brought into contact with the guide member 4 on the outside of the photoconductor belt 1 with a gap holding means.

In addition to the optical system shown in the figure, the laser writing system unit 7 may be an optical system in which a light emitting section and a converging optical transmission body are integrated.

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

Toner hoppers 8B, 9B, 10B and 11B for replenishing toner of respective colors are provided in parallel on the side of and above the developing devices 8, 9, 10 and 11, respectively. , 1
The color image forming apparatus 25 is provided so as to be detachable from the vertical direction indicated by the arrow in FIG.

Since the developing devices 8, 9, 10, 11 and the cleaning device 13 are arranged on the lower surface side of the photosensitive belt 1 in this manner, it is possible to prevent toner scattering and spillage, and thus the charging device 6 It is possible to prevent toner contamination of the laser writing system unit 7.

Reference numeral 12 denotes a transfer device, which is provided to face the surface of the photosensitive belt 1 wound around the rotating roller 3 with a predetermined space as shown in FIG.

Further, the blade 13A and the toner carrying roller 13B of the cleaning device 13 are arranged on the photosensitive belt 1 during image formation.
Is kept at a position apart from the surface of the photoconductor belt 1 and is pressed against the surface of the photoconductor belt 1 as shown in the drawing only at the time of cleaning after image transfer.

The cleaning device 13 is not limited to the right side of the developing device 11 and may be disposed on the left side of the developing device 8 to function.

The unit of the photosensitive belt 1 stretched through the rotating rollers 2 and 3 and the developing devices 8, 9 and 1
A process cartridge 21 shown by a chain line in which the unit in which 0 and 11 are integrated, the cleaning device unit, and the waste toner box 13C are integrated into a unit is configured.

The image forming apparatus 25 of FIG. 1 can be pulled out to the front side (left side of FIG. 2) or the left and right direction.

The process cartridge 21 may be a photosensitive belt unit and a developing device unit, and may be, for example, the photosensitive belt unit alone or a split type in which the cleaning device 13 is attached to the photosensitive belt unit. It does not matter if each unit is pulled out in the direction described above.

Each toner hopper 8B, 9B, 10B, 11
B is provided so as to interfere with the attachment / detachment direction of the process cartridge 21 in order to make the image forming apparatus 25 compact. Therefore, when the process cartridge 21 is pulled out, the toner hoppers 8B, 9B, 10B and 11B are separated from the unillustrated coupling portion. And the process cartridge 21 is pulled out from each of the developing devices 8, 9, 10, and 11.

Color image forming apparatus configured as described above
The process of forming 25 color images is performed as follows.

First, the formation of a multicolor image according to this embodiment is shown in FIG.
Image forming system. That is, the data obtained by the color image data input unit (FIG. 4A) in which the image sensor scans the original image is processed by the image data processing unit (FIG. 4B) to create image data, This is temporarily stored in the image memory (FIG. 4C). Next, the image memory is taken out at the time of recording and is recorded (see FIG. 4).
(D)) is input to the color image forming apparatus 25 shown in the embodiment of FIG.

That is, the color signal output from the image reading device separate from the printer is the laser writing system unit 7.
Input to the laser writing system unit 7, a laser beam generated by a semiconductor laser (not shown) is rotationally scanned by a polygon mirror 7B rotated by a drive motor 7A, passes through an fθ lens 7C, and a mirror 7D. The optical path is bent by 7E, and a bright line is formed on the peripheral surface of the photoreceptor belt 1 to which electric charges have been previously applied by the charger 6 as a charging means.

On the other hand, when the scanning is started, the beam is detected by the index sensor, the modulation of the beam by the first color signal is started, and the modulated beam scans the peripheral surface of the photosensitive belt 1. Therefore, a latent image corresponding to the first color is formed on the peripheral surface of the photosensitive belt 1 by the main scanning by the laser beam and the sub-scanning by the conveyance of the photosensitive belt 1. This latent image is subjected to reversal development in a non-contact state by the developing device 8 loaded with yellow (Y) toner (visual medium) in the developing means to form a toner image on the belt surface. The obtained toner image passes through 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 next copy cycle.

That is, the photoconductor belt 1 has the charger 6
Then, the second color signal output from the signal processing unit is input to the writing system unit 7, and writing is performed on the belt surface in the same manner as in the case of the first color signal described above. The image is formed. 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.

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

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

Further, 11 is a developing device having a black toner, which is formed by superposing a black toner image on the belt surface by the same process. These developing devices 8, 9, 10 and
A direct current or an alternating current bias is applied to each sleeve 11 to perform jumping development with a one-component or two-component developer that is a developing device, and the development is performed in a non-contact manner on the photoreceptor belt 1 whose base is grounded. It is supposed to be done.

The color toner image thus formed on the peripheral surface of the photoconductor belt 1 is loaded in the lower part of the image forming device 25 in the transfer device 12 and the neutralizing plate 12A.
It is transferred to the transfer material sent from the paper feed guide 15 from 14.

That is, the transfer material contained in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16 and one of the uppermost layers is carried out, and the timing is adjusted with the image formation on the photosensitive belt 1 via the timing roller 17. And is supplied to the transfer device 12.

The transfer material subjected to image transfer and charge removal is more reliable than the photosensitive belt 1 which 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. And then move it upwards to the fixing roller.
The image is fused by 18 and then discharged onto a tray 20 via a discharge roller 19.

On the other hand, in the cleaning device 13, the photosensitive belt 1 which has been transferred to the transfer material is further conveyed and the blade 13A facing the rotating roller 3 and the rotating toner conveying roller 13B are brought into pressure contact with each other. After the residual toner is removed and after the completion of the removal, the blade 13A is separated again, and a little later, the toner carrying roller 13B is separated, and a new image forming process is started. In this way, color images are recorded on the transfer material one after another.

When the process cartridge 21 is to be replaced, for example, during maintenance of the image forming apparatus 25, the front door 25A is opened outward in the direction of the arrow as shown in FIG. 2, and the toner hoppers 8B, 9B, 10B and 11B of the respective colors are shown. In some cases, the lid member that does not cause toner spillage at the joint portion is divided in a closed state and pulled out upward, and then the process cartridge 21 is pulled out in the axial direction of the rotary rollers 2 and 3 indicated by arrows. After the predetermined maintenance work is completed, a new process cartridge 21 prepared separately is loaded and the toner hoppers 8B, 9B, 10B for the respective colors are loaded.
11B is loaded in a predetermined position of each developing device 8, 9, 10, 11 and the front door is closed to start a new image formation.

Although not shown, a process cartridge
The pulling-out direction of 21 is not limited to the above-mentioned direction, and not only the pulling-out direction can be set to the opposite side (right side in FIG. 2), but also the pulling-out direction in the rotation direction of the photoconductor belt 1 (left-right direction in FIG. 1) Is also possible.

In any case, the toner hoppers 8B, 9B,
10B and 11B are pulled out from the developing devices 8, 9, 10, and 11 and separated, and then lifted to a predetermined position of the image forming apparatus 25 that does not interfere with the process cartridge 21, and the process cartridge 21 is pulled out.

Therefore, when the process cartridge 21 is replaced, the developing devices 8, 9, 10, 11 and the cleaning device 13, which are toner scattering sources, are arranged below, so that the toner is not spilled and is arranged above the process cartridge 21. Toner contamination of the charging device 6, the laser writing system unit 7 and the like that are currently installed is effectively prevented.

Further, the image forming apparatus is constructed by the construction of the process cartridge 21 and the arrangement of the toner hoppers 8B to 11B.
The 25 is extremely compact.

The color image forming apparatus 25 of the present invention can record not only a color image but also a monochrome image according to a user's request.

[0052]

The developing device and the cleaning device of the color image forming apparatus having the belt-shaped photoconductor of the present invention are arranged below the photoconductor belt unit to form a process cartridge. Since the charger and the laser writing system unit, which adversely affect the image formation, are arranged above them, toner contamination during image formation and maintenance of the image forming apparatus can be effectively prevented.

Further, the size of the image forming apparatus can be reduced by the structure of the process cartridge and the arrangement of the toner hopper.

[Brief description of drawings]

FIG. 1 is a side sectional view showing the configuration of a color image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of the above.

FIG. 3 is a schematic view of the upper surface of the same.

FIG. 4 is a block diagram of an image forming system of the image forming apparatus.

[Explanation of symbols]

 1 Photosensitive Belt 2 Rotating Roller 3 Rotating Roller 6 Charging Device 7 Laser Writing System Unit 8 Developing Device (Yellow) 8B Toner Hopper (for Yellow) 9 Developing Device (Magenta) 9B Toner Hopper (for Magenta) 10 Developing Device (Cyan) 10B toner hopper (for cyan) 11 developing device (black) 11B toner hopper (for black) 12 transfer device 13 cleaning device 13C waste toner box 21 process cartridge 25 image forming device

Claims (4)

[Claims] 1. A color image forming apparatus having at least a charging device, an image exposing device, a plurality of developing devices, a cleaning device, and a transfer device with respect to a stretched belt-shaped image forming body, A charging device, an image exposure device, a plurality of developing devices and a cleaning device, and a transfer device are arranged in this order with respect to the moving direction of the formed body, and the charging device and the image exposure device are provided above the image forming body and a plurality of developing devices and a cleaning device. A color image forming apparatus characterized in that the apparatus is disposed below. 2. A process cartridge in which a belt-shaped image forming body stretched over, a plurality of developing devices, and a cleaning device are divided from each other or are integrated with each other and can be attached to and detached from the image forming device. A color image forming apparatus, wherein a process cartridge can be attached and detached by retracting the toner hopper installed at an interference position where the toner hopper arranged in parallel with the container interferes with the attachment and detachment of the process cartridge. 3. The color image forming apparatus according to claim 2, wherein the process cartridge is pulled out in a rotation axis direction of the image forming body stretched around a plurality of rotation axes. 4. The color image forming apparatus according to claim 2, wherein the process cartridge is pulled out in a moving direction of the image forming body stretched around a plurality of rotation shafts.