JPS6231865A - Image forming unit - Google Patents

Abstract

PURPOSE:To easily facilitate the forming of the image having plural colors and to decrease a space and the cost by being equipped with plural developing devices and the cleaner at the position of the right and left equal distance to the axial line of a photosensitive body and constituting a device so as to function in a different condition for the image forming device. CONSTITUTION:At the position symmetrical to the right and left points to the rotating axis of a photosensitive body 1, a developing device 2 and a cleaner 3 of the same construction are arranged, and an image forming unit P1 is constituted. The unit P1 is mounted to the operating device, a static latent image is developed, this is taken out, inverted upward and downward, mounted to the operating device again and developed by a developing device 2b so that a desired developing device 2a can come to the operating position. Even at the time of the completion of the operation, the magnetic roll is rotated for the prescribed time, and the developing agent of the developing device, which does not contribute to development, does not contact with the photosensitive body. Marks M1 and M2 are stuck to the case of the unit, and the type, the color, etc., of the toner are displayed. Consequently, the image forming of plural colors and the normal rotation reverse rotation image forming can be easily executed, and by decreasing the number of units, the decrease in the space and the low cost can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a replaceable image forming unit used in an image forming apparatus such as an electronic copying machine or an electrostatic recording machine.

Conventional Technology Already, in electronic copying machines, the photoreceptor, developer, cleaner, etc. have been integrated into one unit in order to meet the demand for color copying and to easily maintain the photoreceptor, developer, cleaner, and replenish toner. A system in which multiple image forming units are prepared and loaded with toner of different tones, and in response to a request for copying a desired color, the image forming unit loaded with toner of that tone is attached to a copying machine to perform copying. has been provided (see Japanese Patent Application Laid-Open No. 108553/1983).

Problems to be Solved by the Invention By the way, as explained above, in the working method in which a plurality of image forming units are prepared and the necessary image forming units are attached to a copying machine to form an image, it is difficult to form a large number of images. In addition to requiring a space to store the unit, the photoreceptor is expensive for those that use a photoreceptor drum as the image forming drum installed in the image forming unit. Providing only toner colors results in high unit costs for color image formation.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an arrangement in which the image forming unit is placed at a position equidistant from one image forming drum with respect to the axis of rotation of this image forming drum. , a plurality of developing units and a plurality of cleaners are provided, and the image forming unit is constructed so as to be able to be attached to the image forming apparatus in different states.

This will be explained below with reference to FIG. 1 corresponding to the embodiment.

Reference numeral 1 denotes a photosensitive drum installed as an example of an image forming drum, and developing devices 2a and 2b and a cleaner 3a13b are arranged on the left and right sides of the photosensitive drum 1 at positions equidistant from the rotational axis of the drum 1. constitute an image forming unit, and
This image forming unit is configured to be attachable to the image forming apparatus in different states.

The main components of the developing device 2a include a toner storage chamber 4a, a developer storage chamber 8a, a brush height regulating member 9a, a magnetic roller lOMas developing sleeve 10a, and the like, and the same applies to the developing device 2b. A cleaner 3a that operates together with the developing device 2a is provided on the developing device 2b side, and the cleaner 3b is also provided on the developing device 2a side.
It is provided on the side. This is when the latent image on the photoreceptor drum is developed.
This is based on the necessity of operating the cleaner after the transfer.

Operation According to the desired image forming request, the image forming unit is installed in the image forming apparatus so that the desired developing device 2a among the developing devices of the image forming unit is in the operating position, and in this state, the desired developing device 2a is installed.
Image creation is performed using -. That is, the electrostatic latent image formed on the common image forming drum attached to the image forming unit P1 is generated by one developing device in the operating position among the plurality of developing devices attached to the image forming knee unit. At step 2a, the electrostatic latent image is developed, and the other developing devices are brought into a non-operating state in which they do not contribute to the development of the electrostatic latent image. After development and transfer are completed, the toner remaining on the surface of the image forming drum is removed by a cleaner 3a in preparation for the next image forming.

The image forming unit has the configuration and operation described above, and is equipped with one common image forming drum, multiple developing units, and cleaners, and one image forming unit can have different modes depending on its installation state. It is possible to create images of

Embodiment FIGS. 1 to 4 show a first embodiment of the image forming unit according to the present invention. FIG. 1 is a cross-sectional view of the image forming unit, and FIG. 2 is a cross-sectional view of the image forming unit. FIG. 2 is an explanatory diagram of an image forming process using a copying machine, which is an example of an image forming apparatus. Third
The figure is an explanatory diagram of a situation in which an image forming unit is attached to and detached from an image forming apparatus.

FIG. 4 is an explanatory diagram of a situation in which the image forming unit is rotated and mounted in different positions.

First, the image forming unit P1 will be explained. Figures 1 and 2
In the figure, an image forming unit Pl includes a photosensitive drum 1, which is installed as an example of an image forming drum, and developing units 2a and 2b located on the left and right sides of the photosensitive drum 1 at positions symmetrical with respect to the rotational axis of the drum 1.
and cleaners 3a and 3b are arranged. The developing units 2a and 2b and the cleaners 3a and 3b arranged on the left and right sides have exactly the same configuration.

The developing device 2a (the same applies to the developing device 2b) has a magnetic roller 10Ma, which is sequentially magnetized with S and N poles on the outer periphery, coaxially mounted inside a developing sleeve 10a formed of a conductive non-magnetic material into a cylindrical shape. The developing sleeve 10a is placed close to the surface of the photosensitive drum 1. The toner storage chamber 4a of the developing device is provided with a toner stirring member 5a1 and a toner intensity detection member 6a.
One side faces the developing sleeve 10a with a partition plate 7a' and a toner regulating plate 7a disposed with a slit s left below the partition plate 7a'. A space in which the developing sleeve 10a is accommodated, which is partitioned by the partition plate 7a' and the toner regulating plate 7a, forms a developer preparation chamber 8a, and a height regulating member 9a is provided above and close to the developing sleeve 10a. ing. A developer spill prevention member 17 is still provided between the photoreceptor drum 1 and the outer box of the developer.

The cleaner 3a (same as the cleaner 3b) is located below the developer preparation chamber 8b on the side of the developing device 2b, and is a device consisting of a cleaning blade 18a and a collected toner storage chamber 19a. Explain.

In this figure, it is assumed that the developing device 2a and the cleaner 3a are in operation, and the developing device 2b and the cleaner 3b are in an inactive state.

First, the toner is moved from the toner storage chamber 4a to the toner regulating plate 7a and the partition plate 7a above it by the operation of the stirring member 5a.
The developer is sent to the developer preparation chamber 8a through the slit S between the developer preparation chamber 8a, and is mixed with a magnetic carrier previously loaded in the developer preparation chamber 8a at a constant ratio to prepare a developer. The developer is mixed and stirred while moving counterclockwise on the developing sleeve 10a by the rotation of the magnetic roller 10Ma and the rotation of the developing sleeve 10a, and the layer thickness of the developer is regulated by the height regulating plate 9a. A magnetic brush is formed on the developer sleeve 10a.

On the other hand, a stain charge is applied to the photoreceptor drum 1 by the charging charger 11, and then a light image corresponding to the original image is exposed onto the photoreceptor drum 1 by the image exposure optical system 12 to form an electrostatic latent image. be done.

The electrostatic latent image is developed and visualized by the rubbing of the magnetic brush on the developing sleeve 10a, and then transferred by the transfer charger 14 onto transfer paper fed from the paper feeder 13, and sent to the fixing device 16. and become established.

The toner remaining on the photoreceptor drum 1 is removed by a cleaning blade 18a provided in the cleaner 3a, and then the photoreceptor drum 1 is removed by an eraser lamp 15.
The remaining charge is removed by the process, and the image is prepared for the next image formation.

In this image forming process, a developing device in an inactive state,
That is, it is necessary to prevent the developer in the developing device 2b, which does not contribute to the development of the electrostatic latent image, from contacting the surface of the photoreceptor drum 1. To this end, at the end of the image forming operation, the magnetic roller is controlled to rotate for a fixed period of time even after the photosensitive drum 1 and the developing sleeve 10a have stopped rotating, and the developing sleeve 110
This can be achieved by, for example, reducing the thickness of the developer layer on the photosensitive drum 1 so that the developer does not come into contact with the surface of the photosensitive drum 1.

Also, since the cleaning blade of the cleaner 3b that is not used comes into contact with the photoreceptor drum 1 during image formation, there is a risk of disturbing the electrostatic latent image on the photoreceptor drum 1. By using this insulating material, the electrostatic latent image will not be disturbed. Alternatively, this can be achieved by releasing the cleaning blade that is not in use from being pressed against the photosensitive drum 1.

Next, the state in which the image forming unit P1 is attached to the image forming apparatus and reversed will be explained. FIG. 3(1) shows a state in which the image forming unit P1 is attached to the image forming apparatus. (2), (3) As shown in Figure 4, the image forming unit (P) is pulled out together with the guide rail. By rotating it around the axis, flipping it upside down, placing it on the guide rail again, and pushing it into the image forming device, it can be installed with the developing device on the opposite side of the image forming unit moved to the operating position.

Note that the image forming unit has marks Ml and M2 corresponding to the type and color of the loaded toner on a part of the outer box, and the image forming device detects this mark M1 and determines the operating position. It is also possible to automatically control the developing pressure, etc., suitable for the developing device in the system, and also to visually check the mark M2 from the outside to check the color of the toner, etc.

In the second embodiment shown in FIG. 5, in the image forming unit in the first embodiment, between the developing device 2a and the cleaner 3b,
The partition wall between the developing device 2b and the cleaner 3a has been removed, and it is necessary to load the same type of toner into the left and right developing devices 2a and 2b, but the residual toner collected by the cleaning blade can be stored again. It can be returned to the room and used.

In the third embodiment shown in FIG. 6, the developing devices 2a are symmetrically arranged with respect to a vertical line t passing through the photosensitive drum 1.

This embodiment differs from the first embodiment in that when the developing device 2a operates, the cleaner 3a on the developing device side operates. Note that the cleaning blade 18a of the cleaner 3a
As in the case of the first actual flow side, it is necessary to select a material that does not disturb the electrostatic latent image formed on the photoreceptor drum 1. It is also possible to reuse the residual toner on the image forming drum 1 collected by the cleaner by removing the partition between the cleaner 3a and the toner storage chamber 4a.

In this embodiment, the steps of charging, exposing, developing, and transferring are performed as the photoreceptor drum rotates, but after that, the photoreceptor drum is moved to the image forming device side with residual toner remaining on the photoreceptor drum. It passes through the static elimination, charging, and exposure positions and reaches the cleaner position of the image forming unit.

Therefore, in the case of this embodiment, if one image is processed using the length of one rotation or more of the photoreceptor drum, the influence of the image handled in the previous process may appear, which is undesirable. In this embodiment, after the transfer process of one image is completed, it is appropriate to completely remove residual toner and charge by rotating the photosensitive drum, which is not involved in the image forming process. It is Nao.

The fourth embodiment shown in FIG. 7 is similar to the third embodiment shown in FIG. 6, but the position of the cleaner 3a is different, and when the developing device 2a is operated, the cleaner is A cleaner 3a located on the opposite side of the photosensitive drum is operated.

When using the image forming unit configured as shown in the third and fourth embodiments by attaching it to the image forming apparatus, it is necessary to pull it out from the image forming apparatus when using the developing device on the opposite side of the used developing device. The image forming unit is rotated around a vertical axis as shown in FIGS. 8(1), (2), and (3), and then reattached to the image forming apparatus with its front and rear sides reversed. Therefore, since the image forming unit is not turned upside down, toner does not spill.

A plurality of embodiments related to the image forming unit have been described above, but by using toner that differs in color tone and charging property in each developing device in the image forming unit, it is possible to form a variety of images. .

Table 1 shows specific examples and their relationship with the above embodiments. In example a, each developer stores black toner and color toner, and in example a, each developer stores different color toners. , two-color images can be created with one image forming unit.

Example C is a case where toners having different charging polarities are stored, and a normal image and a reversed image can be formed with one image forming unit. However, in this case, it is necessary to change the developing bias voltage applied to the developing sleeve as the mounting state of the image forming unit changes. Example d is an example in which the same type of toner is stored in each developing unit, and a large amount of image formation and collection and reuse of toner are taken into consideration.

Table 1 Finally, the outline of the drive mechanism of an image forming apparatus using the image forming unit of the present invention will be explained with reference to FIG.

First, as a mechanism on the image forming unit P1 side, the photoreceptor drum 1 has a driving gear 51 and magnetic rollers 10Ma, 10M.
The developing sleeves 10a and 10b have driving gears 54a and 54a, respectively.
4b, the stirring members 5a and 5b each have a driving gear 53.
a and 53b are attached. In addition, gears 53a and 5
4a, 53b and 54b are engaged with each other on the image forming unit side.

On the other hand, on the image forming apparatus side, a drive gear 56 is driven by a drive source (not shown) via a belt 55, and a gear 57.59 is driven by a motor 58.60. There is.

When the image forming unit is installed in the image forming apparatus using the developing device 2a, the drive gear 51 of the photosensitive drum 1 meshes with the gear 56, and the drive gear 52a of the magnetic roller meshes with the gear 5.
9, the drive gears 53a of the stirring member are driven by meshing with the gears 57, respectively. On the other hand, the gears 52b and 53b that drive each member of the developing device that is not in an operating state are connected to a locking member 61.6.
It is configured to be locked by 2.

Furthermore, at the end of the image forming operation, the photoconductor drum and the developing sleeve stop rotating first, and then the magnetic roller stops rotating after a certain time delay, thereby reducing the thickness of the developer layer on the surface of the developing sleeve. The developer is kept in a non-contact state with the surface of the photoreceptor drum. However, even if the image forming unit is inverted and installed in this state as shown in FIGS. 4 and 8, the drive gears of the components of the developing unit that are not in use will be locked by the locking members. In addition, since the unused developing device does not act on the photosensitive drum, the unused developing device does not adversely affect image formation.

Effects of the Invention With the configuration described above, the present invention can easily perform multi-color image formation, normal image formation, reverse image formation, etc. with one image forming unit, and can also perform multi-color image formation. It is possible to quickly respond to various image forming demands such as the demand for images, etc., and it is not only possible to reduce the number of image forming units and reduce storage space, but also to use multiple image forming drums. Since the image forming unit is shared by multiple developing devices, it is possible to provide an image forming unit at a low cost.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of an image forming unit according to the present invention, and FIG. 1 is a cross-sectional view of the image forming unit;
Fig. 2 is an explanatory diagram of the image forming process, Fig. 3 is an explanatory diagram of the attachment and detachment of the image forming unit, Fig. 5 is a cross-sectional view of the image forming unit of the second embodiment, and Fig. 6 is a diagram of the third embodiment. FIG. 7 is a cross-sectional view of the image forming unit of the fourth embodiment, and FIG. 8 is a cross-sectional view of the image forming unit of the third and fourth embodiments. It is an explanatory view of the situation where it is worn in the state. FIG. 9 is an explanatory diagram of a drive mechanism of an image forming apparatus using the image forming unit of the present invention. P11 image forming image forming unit: photosensitive drum, 2a12b,
Developing device, 3a, 3b: Cleaner, 10a, 10b, Developing sleeve, 18a, 18b: Cleaning blade, 1
9a, 19b: Collected toner storage chamber Fig. 2

Claims (1)

[Claims] An image forming apparatus includes one image forming drum on which an electrostatic latent image is formed, a plurality of developing units, and a plurality of cleaners located at positions equidistant from the rotational axis of the image forming drum. An image forming unit characterized in that it is configured so that it can be attached in different states to the image forming unit.