JPH0798540A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To provide a multicolor image forming device constituted so that color mixture or soiling in a device main body is prevented from occurring caused by toner or falling from a developing cartridge without making the device main body large in size. CONSTITUTION:The structure of a supporting body 30 supporting the developing cartridges 4a-4d is made hollow and four arm members 30a-30d are used as air ducts (a), (b), (c) and (d). Then, these air ducts are made to communicate with a center air duct (e) formed at the hollow part of the rotary shaft 31 of the supporting body 30. The duct (e) is extended as a suction duct and connected to a suction fun through an air filter. Besides, an extension air duct 34 pushed out to a photoreceptor drum 1 side at the pressuring action time of the developing cartridges is successively provided on the ducts (a), (b), (c) and (d). Then, the scattering toner is sucked only from just under the drum 1 and a developing sleeve 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus using a plurality of toners as a developer, such as a color copying machine.

[0002]

2. Description of the Related Art In a multicolor image forming apparatus of this type, a process of transferring a recording image formed by charging, exposing and developing on an image carrier onto a transfer material is repeated a plurality of times to transfer the image onto the transfer material. There is a method of forming a superimposed image of a plurality of colors to obtain a color image.

A multicolor image forming apparatus of this type is disclosed in, for example, German Patent Publication No. 2607727 and Japanese Patent Laid-Open No. 50-50.
It has been put to practical use with the configuration described in Japanese Patent No. 935, etc. As shown in FIG. 6, these devices are provided with a photosensitive drum 1 which is an image carrier and a charging roller 3, and a developer and a developer accommodating portion and a developing means for performing development on the right side of the photosensitive drum 1. Are integrated into a cartridge, and a plurality of developing devices 4a, 4b, 4c, and 4d that are removable from the main body of the apparatus and are exchanged when the stored developer is completely consumed are supported by a rotatable support, and the support is rotated. Rotating developing device 9 having developing opening surfaces 5a, 5b, 5c, 5d of developing cartridges 4a, 4b, 4c, 4d on the same circumference centered on shaft 31.
Is provided.

Further, the developing cartridges 4a, 4b, 4
The yellow toner, the magenta toner, the cyan toner, and the black toner are respectively stored in c and 4d.
As shown in FIG. 7, coating rollers 6a, 6b, 6c, 6d and toner regulating members 7a, 7b, 7c, 7d are provided, and the toner coating rollers 6a, 6b, 6c and 6d, the developing roller 8a,
Toner is applied onto the surfaces 8b, 8c and 8d, and the toner regulating members 7a, 7b, 7c and 7d give necessary tribo to the toner. The material of the toner regulating member is preferably nylon or the like when the toner has a negative polarity and is preferably silicone rubber or the like when imparting a positive charge, and a material which is charged opposite to the polarity of the toner is preferable. The peripheral speed of the developing roller 8 is preferably selected in the range of 1.0 to 2.0 times the peripheral speed of the photosensitive drum 1. In addition, the support rotating shaft 31
Attached to the developing cartridges 4a, 4b, 4c,
4d, as shown in FIG.
Development opening surfaces 5a, 5b, 5c, and 5d of b, 4c, and 4d
Are driven so as to always face the photosensitive drum 1. still,
As one means of driving method, for example, Japanese Patent Laid-Open No. 50-9343.
There is a means described in Japanese Patent Publication No.

The developing cartridge 4 eliminates the trouble of toner replenishment and maintenance, and can be easily replaced by a user who does not have special knowledge and skills. Further, as the toner used in the developing cartridge 4, it is preferable to use a one-component developer which has a simple cartridge structure and a low cost and is ready for miniaturization, but a two-component developer may be used.

On the left side of the photosensitive drum 1, there is arranged a transfer roller 10 which holds a transfer material (not shown) and has a function of transferring an image on the photosensitive drum 1 onto the transfer material.

The photosensitive drum 1 is driven in the direction of the arrow at a peripheral speed of 100 mm / sec by a driving means (not shown). The photosensitive drum 1 is constructed by coating a photoconductor made of an organic photoconductor (OPC) on the outer peripheral surface of an aluminum cylinder having a diameter of 40 mm.
It may be S, Se or the like.

A laser diode 11, which constitutes an exposure device, a rotary polygon mirror 13 which is driven to rotate by a high speed motor 12, a lens 14 and a folding mirror 15 are arranged above the main body of the device.

On the charging roller 3 described above, an AC voltage of Vpp (peak-to-peak voltage) of 1500 V is superimposed on a DC voltage of -700 V at an AC frequency of 700 Hz, and the surface of the photosensitive drum 1 is uniformly charged to about -700 V. .

When a signal according to the yellow image pattern is input to the laser diode 11 described above, the photosensitive drum 1 is irradiated through the optical path 16, and the photosensitive drum 1 is irradiated with light at approximately -100V. Become. When the photosensitive drum 1 further advances in the arrow direction, the developing cartridges 4a, 4b, 4c, 4
visualized by d.

Next, the transfer process will be described in detail. The transfer drum 9 is constructed by winding a metal cylinder 19 having a diameter of 156 mm, an elastic layer 20 made of urethane foam made of Inoac having a thickness of 2 mm and winding a PVDF 21 having a thickness of 100 μm on the upper layer.

The transfer material fed from the transfer material cassette 17 to the transfer roller 10 by the pickup roller 18 is held by the gripper 22.

The toner image on the photosensitive drum 1 is transferred onto a transfer material by a voltage applied between the photosensitive drum 1 and the transfer roller 10 from a power source (not shown). At the same time, the charge is injected into the transfer material so that the transfer material 10 is attracted to the transfer roller 10. If necessary, apply a voltage between the suction rollers 23,
It may be adsorbed in advance.

In addition to the above steps, magenta, cyan,
By carrying out also for black, toner images of a plurality of colors are formed on the transfer material. The transfer material is separated from the transfer roller 10 by the separation claw 24, and the toner image is fused and fixed to the transfer material by a conventionally known fixing device 25 that performs heating and pressing to obtain a color image.

The transfer residual toner on the photosensitive drum 1 is cleaned by a cleaning device 26 such as a known fur brush and blade means. Further, it is preferable that the toner on the transfer roller 10 is also cleaned by a transfer roller cleaning device 27 such as a fur brush or a web, if necessary.

By the way, in the image forming apparatus as described above, toner is scattered or spilled from the developing cartridge 4 in the rotary developing device 9, and the scattered or spilled toner is transferred to the developing cartridges 4 of other colors. There is a problem that color mixture occurs due to mixing, and an image with a correct color tone cannot be obtained. In addition, there is a problem that the main body of the image forming apparatus or the rotary developing device 9 is contaminated by the scattered or spilled toner.

The above-mentioned toner scattering mainly occurs during development, and the cause thereof is the developing sleeve 8 of the developing cartridge 4.
When using a centrifugal force due to the rotation of the developing roller and a superposed alternating current as the developing bias, it is considered that the developer reciprocates or vibrates between the developing sleeve 8 and the photosensitive drum 1 due to the alternating current component.

Further, the toner spill means that the developing cartridge 4 is externally vibrated and spills from the developing sleeve 8 side in the developing cartridge 4 to the outside of the developing cartridge. This occurs when the cartridge 4 is attached to or detached from the rotary developing device 9, or when the developing cartridge is replaced.

Therefore, in order to suck the scattered or spilled toner as described above, a suction duct 40 is provided near the developing sleeve of the developing cartridge 4 facing the photosensitive drum 1 as shown in FIG. It is considered to suck scattered or spilled toner at 40.

[0020]

However, if there is a suction duct in the vicinity of the developing sleeve of the developing cartridge as shown in FIG. 6, a position apart from the developing sleeve is provided in order to avoid interference with the revolving operation of the rotary developing device. However, there is a problem that a sufficient suction force cannot be obtained, and if the suction force is too high, the toner on the photosensitive drum is also sucked.
Further, the gap between the transfer drum and the suction duct can be widened by enlarging the photosensitive drum, but there is a disadvantage that the size of the photosensitive drum becomes expensive and the device becomes large.

Therefore, an object of the present invention is to provide a multicolor image forming apparatus capable of preventing color mixture and stains in the apparatus body due to toner scattered or spilled from a developing cartridge without increasing the size of the apparatus. Is.

[0022]

The above object can be achieved by a multicolor image forming apparatus according to the present invention. In summary, according to the present invention, an image carrier on which a latent image is formed, a developer accommodating section for accommodating a developer, and a developing means for developing are integrally formed into a cartridge, and a plurality of units detachable from the apparatus main body are detachable. And a plurality of developing cartridges, wherein the plurality of developing cartridges are rotatably arranged around the rotation mechanism supporting shaft parallel to the central axis of the image carrier by the developing cartridge supporting body, and the selected developing cartridge is In a multicolor image forming apparatus that rotates to a position facing the image carrier and sequentially develops to obtain a multicolor image, a developer scattered from the plurality of developing cartridges on the rotation mechanism support shaft and the developing cartridge support. A suction duct for sucking
The suction duct sucks the developer scattered at the time of development,
The multicolor image forming apparatus is characterized in that it can be extended with the movement of the developing cartridge.

The suction duct for sucking the developer scattered from the plurality of developing cartridges and the ozone suction duct for sucking ozone generated from the charger of the image carrier are both sucked by a single suction fan. The suction of the scattered developer is positively performed during the development, and the suction duct for sucking the developer scattered by the rotation mechanism is blocked during the non-development, and the ozone generated from the charger is positively suctioned. It is preferable.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multicolor image forming apparatus according to the present invention will be described below in more detail with reference to the drawings. The same members as those described above are designated by the same reference numerals and the description thereof will be omitted.
Further, mainly the characteristic part of the present invention will be described.

An embodiment of the multicolor image forming apparatus according to the present invention will be described in detail with reference to FIGS.

In the present embodiment, the rotary developing device 9 includes four developing cartridges 4a, 4b, as shown in FIG.
A support body 30 that detachably supports 4c and 4d is provided. As shown in FIGS. 1 and 3, the support body 30 includes arm members 30a, 30b, which are combined in a substantially cross shape in cross section,
30c and 30d, and the support rotary shaft 31 is provided at the center thereof.
Has been penetrated. Arm members 30a, 30b, 30c, 3
0d has a hollow structure, so-called air passages a, b,
c and d are formed. Similarly, the support rotary shaft 31 has a hollow structure and forms a central air passage e. Then, the air passages a, b, c, d are communicated so as to be gathered in the central air passage e, and the central air passage e is provided with an air filter 35 provided on an extension thereof as shown in FIG. Connected to the suction fan 33. Furthermore, a suction fan power source 34 is connected to the suction fan 33.

In this embodiment, as shown in FIG. 1, the developing cartridges 4a, 4a arranged in the rotary developing device 9 are arranged.
b, 4c, and 4d move toward the photosensitive drum 1 at the developing position (hereinafter referred to as pressurizing operation), maintain the gap between the photosensitive drum 1 and the developing sleeve 8 at 300 μm, the developing operation ends, and the rotary developing device 9 rotates. When performing the operation, the rotary developing device 9 is again used.
It moves in the direction of the central axis 31 and is housed in the rotary developing device 9 (hereinafter referred to as a pressure releasing operation), and avoids interference with the photosensitive drum 1 during rotation.

Further, as shown in FIG. 3, the developing cartridge has a cover member 37 on the outer side of the main body, and the main body of the developing cartridge rotates while keeping the horizontal position as the rotary developing device rotates. The cover member rotates while being fixed to the support 30. Therefore, the opening of the developing cartridge is covered at a position facing the photosensitive drum so that the user does not accidentally touch the developing sleeve when the developing cartridge is removed from the main body.

The cover member 37 is provided with a claw 41 as shown in FIG. 3, and the support 3 of the rotary developing device 9 is used by the claw 41 when the developing cartridge is pressed.
0 of each arm member 30a, 30b, 30c, 30d
The extension air passage 34 provided at the position is pushed out to the photosensitive drum 1 side. When the extended air passage 34 is pushed out, the scattered toner is sucked only from just below the gap between the photosensitive drum 1 and the developing sleeve 8 as shown by an arrow x in FIG.

If suction is performed simultaneously from the four air passages a, b, c, d, the suction force is reduced and the force for sucking scattered toner from the developing cartridge is weakened. An air passage blocking member 32 made of an elastic member is provided at the entrance of the central air passage e, so that even if the rotary developing device performs a revolving operation, the wind located below the developing portion is always shown by a in FIG. The suction is performed only from the path (a in this case) as shown by the arrows x-y-z. Toner scattering occurs when the electrostatic latent image on the photosensitive drum is being developed by the developing cartridge, and most of it consists of atomized toner. The suction wind velocity may be 0.1 m / s or more, preferably 0.5 m / s or more.

In this embodiment, since the suction port is arranged directly below the developing sleeve, there is an advantage that the efficiency is very good and the load on the suction fan can be reduced. Also,
Although the scattered toner may be accumulated under the developing sleeve and may be spilled at the time of development, in the present embodiment, since the suction port is arranged directly below the developing sleeve, such spilled development is not performed without increasing the suction force. It is possible to inhale the agent. If the suction force is increased to suck the spilled developer, the toner on the developing sleeve is also sucked, which is very uneconomical. However, in this embodiment, it is not necessary to increase the suction force. No needlessly sucking the toner of, the toner is not consumed unnecessarily, and the air filter is not replaced.

Further, according to the present embodiment having the above-mentioned structure, the scattered developer can be more efficiently sucked, the suction fan can be downsized, and the rotation operation of the rotary developing device can be interfered with. Since it does not happen, space saving is also achieved.

Next, another embodiment of the multicolor image forming apparatus according to the present invention will be described with reference to FIGS.

The ozone generated from the charging roller may deteriorate each part if it spreads inside the machine without being sucked. Therefore, the surroundings should be sucked at the time of charging, filtered by the ozone filter, and discharged to the outside of the machine. I won't. However, if the vicinity of the charger is strongly sucked during development, the toner scattered from the developing cartridge is also sucked and the photosensitive drum and the like are contaminated. Therefore, in order to more positively suck the periphery of the charger, it becomes necessary to switch the suction force.

Therefore, in this embodiment, as shown in FIG. 4, a suction duct 38 for scattered toner and an air filter 35 for collecting toner are provided on one side of the rotary developing device, and the charging roller 3 is also provided.
An ozone suction duct 39 for sucking ozone generated from the vicinity is provided, and this ozone suction duct is connected to the toner suction duct 38 of the first embodiment, and the ozone filter 3
Both the ozone from the charging roller and the toner scattered during the development can be sucked by one suction fan 33 through No. 6.

With the above-described structure, in this embodiment, when the developing cartridge is pressurized and developing is performed as shown in FIG. 1, air is supplied from both the rotary developing device 9 and the vicinity of the charging roller 3. Since the suction is performed, the suction force in the vicinity of the charging device is weakened and the scattered toner is not sucked toward the charging device. Further, as shown in FIG. 5, the rotary developing device rotates and the developing cartridge 4 causes the photosensitive drum 1 to rotate. When it is not opposed to, the air passage is blocked by the air passage blocking member 32 provided on the support rotating shaft 31, and only the vicinity of the charging roller 3 is sucked, so that the air near the charging roller is efficiently sucked. Made possible

As described above, in this embodiment, it is possible to suck both the scattered toner and the ozone in the vicinity of the charger with the optimum suction force by using one suction fan without providing a special switching fan. . Further, the present embodiment has an advantage that the number of fans can be one, no special switching means is required, the cost is very low, and the size can be reduced.

In the present embodiment, the same fan is used to suck the scattered toner and the ozone, but the present invention is not limited to this. For example, cooling of the electric circuit and suction around the humidity sensor for detecting the in-machine humidity can be performed. It is also possible to prevent the temperature rise of the scanner by providing an opening near the scanner above the rotary developing device and positively sucking air around the scanner.

[0039]

As is apparent from the above description, in the multicolor image forming apparatus according to the present invention, the rotating mechanism supporting shaft and the developing cartridge supporting member are provided with the suction duct for sucking the developer scattered from the plurality of developing cartridges. By disposing the suction duct to extend with the movement of the developing cartridge so as to suck the developer scattered at the time of development, it is possible to mix the color with the toner scattered or spilled from the developing cartridge without increasing the size of the apparatus. It is possible to prevent the inside of the apparatus body from being soiled. This makes it possible to obtain a good image and prevent stains on the recording material.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a multicolor image forming apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing a characteristic part of the present invention.

FIG. 3 is an enlarged view of the developing device in FIG.

FIG. 4 is an explanatory diagram showing a characteristic part of another embodiment of the multicolor image forming apparatus according to the present invention.

5 is an overall configuration diagram of a multicolor image forming apparatus including the characteristic portion of FIG.

FIG. 6 is an overall configuration diagram showing a conventional multicolor image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 photosensitive drum (image bearing member) 4a developing cartridge 4b developing cartridge 4c developing cartridge 4d developing cartridge 9 rotating developing device 30 developing cartridge support 31 rotating mechanism supporting shaft 33 suction fan 34 extension air passage 38 suction duct 39 ozone suction air passage ( Ozone suction duct) a Airway b Airway c Airway d Airway e Central airway

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G03G 21/00 538 2107-2H (72) Inventor Yoichiro Maebashi 3-30-2 Shimomaruko, Ota-ku, Tokyo No. Canon Inc. (72) Inventor Tetsuya Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tatsuya Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Company (72) Inventor Haruo Fujii 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Sasame 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72 ) Inventor Tatsuhiko Hayakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (2)

[Claims] 1. A plurality of developing cartridges detachably mountable to an apparatus main body, wherein an image carrier on which a latent image is formed, a developer containing portion containing a developer, and a developing means for developing are integrated into a cartridge. And a plurality of developing cartridges are rotatably arranged around the rotation mechanism supporting shaft parallel to the central axis of the image bearing member by the developing cartridge supporting member, and the selected developing cartridge is mounted on the image carrying member. In a multicolor image forming apparatus that rotates to a position facing the body and sequentially develops to obtain a multicolor image, suction of the developer scattered from the plurality of developing cartridges is applied to the rotation mechanism support shaft and the developing cartridge support. A suction duct for performing is provided, and the suction duct can be extended with the movement of the developing cartridge so as to suck the developer scattered at the time of development. Multi-color image forming apparatus. 2. The suction duct for sucking the developer scattered from the plurality of developing cartridges and the ozone suction duct for sucking ozone generated from the charger of the image carrier are both provided by a single suction fan. The developer that has been sucked and scattered is positively sucked, and the developer is sucked by the rotating mechanism when the developing is not performed.The suction duct is blocked and ozone generated from the charger is positively sucked. The multicolor image forming apparatus according to claim 1, wherein