JP3064369B2 - Image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

(Prior art)

2. Description of the Related Art In an electrophotographic image forming apparatus, for example, a copying machine, many apparatuses for forming a full-color image are known. Broadly speaking, four types of methods can be considered as shown in FIG. In FIG. 1A, a latent image is formed on a latent image carrier 1, for example, a photosensitive drum, by color separation image light from a writing device 2, and is developed by a developing device of a developing device 3 containing a developer of a corresponding color. Thus, a visible image, for example, a toner image is formed. The developed image is transferred to a transfer material 5 wound around a transfer drum 4 under the action of a transfer device 6. The photosensitive drum 1 rotates by the number of times corresponding to the separation color to form a visual image of each color,
At the same time, a visible image is transferred to the transfer material on the transfer drum 4 rotating at the same time. In this way, a visible image of a different color is transferred onto the transfer material on the transfer drum 4 in each rotation. When the transfer of each color is completed, the transfer material 5 is separated from the transfer drum 4, sent to a fixing device 7, fixed and discharged. The photoreceptor drum 1 after the transfer is cleaned by the cleaning device 8 and enters the next image forming process.

In the method shown in FIG. 1B, a latent image is written on a latent image carrier 1, for example, a photosensitive drum, by a writing device 2 to form a latent image, and a developing device 3 of a corresponding color develops a latent image. Contact development is performed to form a visible image for each rotation, and the photosensitive drum 1 is rotated three or four times, for example, three or four times determined by the number of separation colors, so that a plurality of colors of the latent image are superimposed on the photosensitive drum 1. After forming a visual image of each color, the image is transferred to a transfer material 5 fed from a sheet feeding device under the action of a transfer device 6, fixed by a fixing device 7, and discharged. The photoreceptor drum 1 after the transfer is cleaned by the cleaning device 8 and enters the next image forming process.

In the method shown in FIG. 1C, a separation image is written on a latent image carrier 1, for example, a photosensitive drum 1 by a writing device 2 to form a latent image. To form a visualized image, and the visualized image is transferred to an intermediate transfer member 4, for example, an intermediate transfer drum, which is moving in synchronization with the latent image carrier 1 under the action of the intermediate transfer device 9. Photoconductor drum 1
Each time the intermediate transfer drum 4 rotates, the visualized image formation and transfer of each separation color are repeated. For example, a multicolor image is transferred to the intermediate transfer drum 4 by three to four rotations. The visible image formed by superimposing the transfer on the intermediate transfer drum 4 is transferred once to the transfer material 5 fed from the paper feeding device under the action of the transfer device 6,
The sheet is further fixed by the fixing device 7 and discharged. After the transfer, the photosensitive drum 1 is cleaned by the cleaning device 8 and the intermediate transfer drum 4 is cleaned by the cleaning device 8 ', and the next image forming process is started.

In the method shown in FIG. 1D, a latent image carrier 1, for example, a photosensitive drum is arranged for each color. For example, in the case of four colors, four photosensitive drums 1 are arranged. A latent image is formed on each of the photosensitive drums 1 by an optical writing device 2 provided separately, and a visible image is formed by a developing device 3 provided individually, and is conveyed by conveying means 4 ′, for example, a conveying belt. The image is transferred onto the transfer material 5 under the action of the transfer device 6. The transfer material after the transfer is sent to the next photosensitive drum 1 by the conveying means 4 ', and the visual image of the photosensitive drum 1 is transferred. After the transfer, the photosensitive drum 1 is cleaned by the cleaning device 8 and the next image forming process is started. In FIG. 1D, the configuration around each photoconductor drum 1 is formed in the same manner. For example, when four photoconductor drums are arranged, it is easy to distinguish the constituent members corresponding to each photoconductor drum. Therefore, the members corresponding to each other are denoted by the same reference numerals, and the reference numerals are added with the suffixes “a”, “b”, “c”, and “d” to clarify the respective latent image carriers. Last photoconductor drum, for example, photoconductor drum 1d
Is transferred to the fixing device 7 by the conveying means 4 ', and is fixed and discharged.

In the above four types, the image forming speed (copy speed and print speed) is 10 sheets / sheet in FIGS. 1A, 1B and 1C.
1 minute or less, but is 10 sheets / minute or more in the method of FIG. 1D, and the method of FIG. 1D can be speeded up.

The above four types of image forming apparatuses have different advantages and disadvantages in various image forming performances such as image forming speed and image quality. If the user wants to obtain an image forming apparatus having a new desired performance, a new apparatus must be purchased separately from the image forming apparatus conventionally used. Each time an increase in functionality is required, the entire device must be replaced, which is costly and time-consuming.

At first, an image forming apparatus for forming a black-and-white image was installed. It was necessary to replace the entire device.

Yellow, magenta, and normal color images
In order to form a single-color image such as blue, red, or green against full-color image formation obtained by superimposing the separated colors of cyan, it is possible to respond by exchanging the color of the developer in the developing device. And a full-color image are set in advance, and it is not possible to form an apparatus which enables a user to form an image of a desired color, for example, a favorite color. A method of forming a single color by simply using a plurality of single colors such as blue and red (also referred to as a multi-color method or a functional color method) is a method of forming a full color by separating colors such as yellow, magenta, and cyan ( The Victorian color system) emphasizes color reproducibility and gradation, and requires different performance. Thus, it has been impossible for the user to easily configure an apparatus for forming images of different performances at any time.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide an image forming apparatus that allows a user to easily configure apparatuses having different performances.

[Means for solving the problem]

The present invention solves the above-mentioned problems by providing a base unit containing a latent image carrier, a transfer unit, and a control device, and a full-color image detachable from the base unit and forming a latent image based on image information on the latent image carrier. A writing unit in which constituent members relating to a method arbitrarily selected from a single-color image forming method are incorporated, and a detachable / removable latent image carrier corresponding to the selected image forming method. A developing unit in which a member for developing a latent image on the body and a developer are stored; and a cleaning unit which is detachable from the base unit and has a built-in member for cleaning the latent image carrier after transfer. A unit, a paper unit detachable to the base body unit, and having a built-in means for storing paper and a means for feeding paper, and a member for fixing the transferred paper. It was solved by the image forming apparatus characterized by having a built fuser unit.

[Action]

According to the present invention, an image forming apparatus includes a combination of a base unit that stores a latent image carrier, a writing unit, a developing unit, a cleaning unit, a paper unit, and a fixing unit. It is detachable from the base unit, can be freely replaced for each unit, and a desired type of image forming apparatus can be formed. At this time, since each unit is disposed to face the latent image carrier in the base unit, the functions of writing, developing, and cleaning the image on the latent image carrier can be performed by a simple operation of replacing and detaching each unit. it can. By changing the combination of the writing unit and the developing unit, it is possible to appropriately select and form a multi-color and pictorial color system. By changing the paper unit, it is possible to easily select the image formation on one side of the transfer material or the double-sided image formation.

〔Example〕

 The details of the present invention will be described based on an embodiment shown in the drawings.

In FIG. 2, various units having casings having substantially the same shape are formed on the base body unit 11 in a detachable manner. Various units include writing unit 12,
A developing unit 13, a paper unit 14, a cleaning unit 15, a fixing unit 16, a reading unit 17, and the like are used.

The base base unit 11 is provided with a support portion 18 for attaching and supporting various units. The support part 18 can be formed as a shelf rack as shown in FIG. 2, for example. The protruding support member 18a constituting the rack can be formed integrally with the casing 11a of the base unit 1, but can also be formed to be removable. In addition, it can be made expandable and contractible. In FIG. 2, each unit such as the writing unit 12 can be attached to and detached from an appropriate portion of the support portion 18, for example, the rack 18.

In the casing 11a of the base body 11, the latent image carrier 1 can be formed as a latent image carrying belt wound around a driving roller 19 and a driven roller 20, as shown in FIG. Writing unit 1 for latent image carrying belt
2. A developing unit 13 and a paper unit 14 are mounted along one running surface of the latent image carrying belt 1 to enable latent image formation and visible image formation. The visible image formed on the latent image carrying belt 1 is
It can be formed such that the image is transferred from the latent image carrying belt 1 to a sheet fed from the sheet unit 14, for example, a transfer material under the action of a transfer unit 21, for example, a transfer roller, and then fixed by the fixing unit 16. The latent image carrying belt 1 after the transfer is cleaned by the cleaning unit 15. In this case, the fixing unit 16 and the cleaning unit 15 are conveniently arranged along the running surface on the opposite side of the latent image carrying belt 1. The fixing unit 16 can be formed integrally with the base unit 11.

As the writing unit 12, for example, a first writing unit 12a using a laser beam, a second writing unit 12b using an LED array, and the like can be configured.

The first writing unit 12a includes a charging member, a semiconductor laser (L
D), a polygon mirror, a circuit board and the like are built in, and the second writing unit 12b contains a charging member, an LED array, a circuit board and the like.

As the sheet unit 14, a sheet cassette unit 14a for feeding a plurality of sheets set in advance to one sheet, a sheet stock unit 14b for temporarily storing the image-formed sheet and feeding it again are formed. be able to.

The cleaning unit 15 includes a main cleaning unit 15a having a cleaning blade and an auxiliary cleaning unit 15b having a cleaning brush, a neutralizing lamp, and the like.
Can be provided separately, or both can be formed as one unit.

The casing 11a of the base body unit 11 is formed with a paper feed port 22 for introducing paper from the paper unit 14 and a discharge port 23 for discharging to the fixing device, and when the fixing unit 16 is integrally formed, the fixing unit A discharge port 25 for discharging the sheet after fixing is formed on the side of 16.

FIG. 3 shows an example of assembling the various units. The writing unit 12 (selectably from the first writing unit 12a, the second writing unit 12b, and the like) is selected from the lower right side of the drawing of the base body unit 11. Yes), the developing unit 13 is mounted. As a developing unit, for example, three developing devices for black developing, blue developing, and red developing are mounted from the lower side to form a multi-color system. Paper feed slot on top
Paper cassette unit 14a and paper stock 14b near 22
Are arranged side by side. A reading unit 17, an auxiliary cleaning unit 15b, and a main cleaning unit 15a are mounted on the side opposite to the side on which the writing unit 12 and the developing unit 13 are mounted, and on the left side of the drawing. In this example, a latent image is formed on the latent image carrying belt 1 by the writing unit 12, and a developing unit of a desired color among black, blue, and red is formed.
Then, the image is developed on the sheet 13 and transferred to the sheet from the sheet cassette unit 14a and fixed. The latent image carrying belt 1 after the transfer is cleaned by the cleaning unit 15. The reading unit 17 reads the toner image on the latent image carrying belt 1 as necessary.
To check and correct image forming conditions.

The reading unit 17 includes, for example, an illumination lamp, a lens, and a CC.
D is built in so that an image on the latent image carrier 1 can be read.

In the arrangement of the paper unit 14 shown in FIG. 3, as shown in FIG. 4, the paper fed from the lower paper feed cassette unit 14a as shown by the arrow a passes from the paper feed port 22 to the latent image carrier. 1 and is transferred by the action of the transfer roller 21, sent to the fixing device, and fixed by the fixing roller pair 26 in the fixing device 16. The sheet on which the image has been fixed and on which the image has been formed is directly discharged from the discharge port 25 to the discharge tray 30 (FIG. 6) as indicated by an arrow a ″. As shown by an arrow a ', the sheet to be fed is reversed after exiting the fixing roller pair 2b, and is introduced into the sheet stock unit 14b from above through a return port 29 formed in the casing 11a of the base body unit 11. In the stock unit 14b, the paper is accommodated with the paper cassette unit 14a and the front and back and front and back reversed, and the paper from the paper cassette unit 14a is reversed in front and back and front and back, that is, from the rear end side. The sheet is fed to the transfer position as shown by the arrow b, and the sheet is transferred to the back surface.

The paper after the back side fixing can be discharged as shown by an arrow a "as it is,
It can also be stacked on 14b as shown by arrow b '. This is particularly convenient for page alignment.

If necessary, sheets on which images are formed on only one side can be stacked on the sheet stock unit 14b.

3, the configuration of the image forming apparatus can be modified as shown in FIG.

FIG. 5 shows the writing unit 12 and the developing unit 13 as a set of the writing unit 12 and the developing unit 13 for each color to be developed.
Place. Writing unit for yellow from below as an example
12 and a developing unit 13, then a writing unit 12 and a developing unit 13 are arranged in the order of magenta, cyan, and black,
The sheet cassette unit 14a is arranged at the top. In this example, first, a yellow latent image is formed on the latent image carrying belt 1 by the first writing unit 12, developed with the yellow toner by the developing unit 13, and the next writing unit is written on the yellow toner image. A magenta latent image is formed by 12, a magenta toner image is formed by the developing unit 13, and a cyan, black (black) and toner image are further formed on top of each other, and finally fed from the paper feed cassette unit 14 a The toner image of the latent image carrying belt 1 is transferred to a sheet. The sheet after the transfer is fixed by the fixing unit 16 and is discharged. The latent image carrying belt 1 after the transfer is cleaned by the cleaning unit 15. The toner image on the latent image carrying belt 1 is read by the reading unit 17 as necessary, and the image forming conditions and the like are checked and corrected.

In the example of FIG. 5, contrary to the example of FIG. 3, the reading unit 17 is disposed after the cleaning unit 15 (the auxiliary cleaning unit 15b and the main cleaning unit 15a).

As shown in FIG. 6, the casing 11a of the base body unit 11 is formed with an insertion port 27 for a unit supported by a support member 18a constituting a rack.
~ 15 tips can be inserted. A connector 28 is provided on the casing 11a, and is fitted with a connector facing portion 28a provided on each of the units 12 to 15 to enable connection of an electric system or the like.

Although only three insertion ports 27 are provided in FIG. 6, eight insertion ports 27 are provided corresponding to the example shown in FIG.

Each unit (typically, the writing unit 12 is shown in the figure)
Insertion port 2 of casing 11a for positioning when mounting
One positioning hole 31 is provided on each side of 7 and a positioning pin (not shown) is provided in each unit (for example, the writing unit 12).
The positioning pin is inserted into the positioning hole 31 at the time of mounting, so that accurate positioning is performed. Further, each unit may be provided with a clamp means so that the unit does not easily fall off when mounted.

In particular, the positional accuracy of the LD of the writing unit in the sub-scanning direction, and
The requirements for the positional accuracy of the LED array in the sub-scanning direction are severe in the case of full-color image formation. The positioning holes 31 are provided corresponding to the vicinity of both ends of each unit, but a mechanism capable of manually or automatically moving one of the positioning holes 31 or the pin may be used. The position adjustment of the positioning hole 31 is performed based on information from the reading unit 17.
The determination can be made based on the print image once formed on the latent image carrier 1. Advantageously, this adjustment can be performed by both the user and the service person.

In addition to the latent image carrier 1, a control device for controlling each unit is built in the base body unit 11. As an example of the control device, it can be configured as shown in FIG.

Based on image information signals from an external device such as a personal computer from the main control board, the base unit,
It controls the writing unit, developing unit, paper unit, cleaning unit, reading unit, and fixing unit.

The substrate base unit is provided with, for example, a transfer roller drive motor, a drive roller motor for driving the latent image carrier belt, and means for controlling voltage application to the transfer roller, and is controlled by a signal from the main control board.

There are LD type and LED array type in the writing unit,
The information of each system is sent out by coded system information. Charging member power ON / OFF for charging, charging potential sensor to detect surface potential after charging, write signal memory to store writing signals, polygon motor control for LD system, automatic sub-scan information A member related to the movement control of the positioning hole for performing the correction can be provided, and a sensor for detecting the timing of starting writing can be provided.

In the developing unit, the color information of the toner color is coded and held, and residual toner is detected by toner detection. The drive of the sleeve motor is controlled to control the rotation of a roller for transporting the toner to the surface of the latent image carrier.

In the paper unit, unit information for identifying the paper cassette unit or the paper stock unit is coded and held. Paper size detection detects the size of the paper in the paper cassette, paper remaining amount detection is provided in both the paper cassette unit and the paper stock unit, and rotation of the paper feed rollers provided in the paper cassette unit and the paper stock unit Driving control is performed by a feed roller motor.

If there is a main cleaning unit and an auxiliary cleaning unit in the cleaning unit, both are controlled, and toner full detection and blade ON / OFF are performed in the main cleaning unit, and the state where the collected toner is full is performed. This is done by detecting fullness, and prompts the replacement of the cleaning unit. The blade ON / OFF controls the operation of the solenoid so that the blade is brought into contact with the photoconductor drum or not. The brush drive motor and static elimination lamp (Q / L) ON / OFF are added to the auxiliary cleaning unit. The brush performs contact and non-contact control in synchronization with the blade, and at the time of contact, the brush drive motor rotates.

The ON / OFF of the static elimination lamp may serve both as a static elimination function for the entire surface and an erase depending on the size of the printing paper.

The reading unit reads a toner adhesion pattern on a latent image carrier formed specifically for reading. The illumination lamp is illuminated only when reading the special toner adhesion pattern, and is imaged on the CCD. The calculation information is a content that is synchronized with the toner adhesion pattern and is fed back to other units regarding the deviation between fine lines and the adhesion density.

The fixing unit performs temperature detection and heater ON / OFF control to keep the temperature of the fixing roller constant, and drives a motor that rotates the roller when the transferred paper is passed.

A detachable sensor is installed near the connector and the base unit, and detects whether or not various units are mounted.

It is convenient to always install the detachable sensor at the unit opening of the casing 11a. Immediately after the power is turned on, the detachable sensor functions, and connects to the power supply only to the connector to which the unit is mounted to supply power. When any unit is removed after power-on, all power is turned off by the detachable sensor that is detected at regular intervals.
Add a circuit.

A power supply unit is provided to supply voltage to each unit.

By the control device shown in FIG. 7, even if a unit having any function is mounted on any support member (rack), the function is operated based on an external signal from a personal computer or the like, and a mono-color or full-color printout is performed.

To further explain each unit, the writing unit 12
In the first writing unit 12a of the semiconductor laser (LD) optical scanning method, as shown in FIG. 8, a charging member 42, a semiconductor laser light source 43, a polygon mirror 44, fθ An optical path 45 and the like are formed by an optical system including a lens and the like. A circuit board 46 is disposed in the casing 41.

In the second writing unit 12b using a light emitting diode array (LED), as shown in FIG.
1, a charger 52 and an LED array 53 are arranged side by side on a surface approaching the latent image carrier 1, and a circuit board 54 is arranged on the opposite side.

8 and 9, the chargers 42 and 52 are arranged on the upstream side in the moving direction of the latent image carrier 1 and
The optical path 45 by 43 and the LED array 53 are arranged so as to emit light on the downstream side.

The chargers 42 and 52 are convenient because a method that does not rely on contact with a corotron or the like does not disturb the toner image on the latent image carrier.

The developing unit 13 is variously configured depending on the developing method, but there is a two-component method in which a carrier and a toner are mixed by a dry developing method and the developer is conveyed to a developing area by a magnetic sleeve.
For example, as shown in FIG. 10, a developing sleeve 62 is disposed at an outlet of the casing 61, and conveys the developer to the latent image carrier 1. As a means for mixing the carrier and the toner, various methods such as a mixing roller, a paddle roller, and a screw can be used, but are omitted in the drawing. The casing 61 contains a developer.

In the one-component system in which the developer is transported to the developing area by a toner roller having only the toner adhered on the sleeve 62, the toner contained in the casing 61 is transported to the developing sleeve 62 by a feeding unit (not shown).

When the direction of the arrangement of the developing units 13 is set, a method using a liquid developer may be adopted.

As the developer contained in the casing 61, toner of each color is selected and used. For example, for a single color, red, blue, green, black, etc.
One of the toners of each color such as magenta and cyan is stored in each casing 61. Therefore, casings 61 of the required number of colors are prepared.

The development system includes contact development and non-contact development, both of which can be used. However, in the case of superimposing and transferring the latent image on the latent image carrier 1, non-contact development is preferred. When the intermediate transfer member is arranged in the base member 11 in addition to the latent image carrier, contact development can also be used.

The paper unit 14 stores paper in advance like a normal paper cassette, temporarily stores the paper returned from the base unit 11 and the paper cassette unit 14a that feeds one sheet according to a paper feed command, and re-feeds the paper. Paper stock unit for paper
14b It can be composed of units of other necessary configurations.

The paper feed cassette unit 14a includes, as shown in FIG.
A bottom plate 72 for supporting the paper and a paper feed roller 73 are built in the casing 71, and the paper 74 placed on the bottom plate 72 is fed to the paper feed roller.
A pressing member that pushes the bottom plate 72 toward the paper feed roller 73 in order to press the base plate 73 at a predetermined pressure is disposed, for example, a spring 76 or the like. The paper feed cassette unit 14a is formed in the casing 11a of the base body unit 11 so as to be mountable at a position where the paper fed from the outlet 75 of the casing 71 to the paper feed port 22 is introduced.

The paper stock unit 14b, as shown in FIG.
An inlet 82 is formed above the casing 81, and an outlet 83 is formed below the casing 81. A bottom plate 84 on which a sheet 85 is placed is provided at the bottom of the casing 81, and a paper feed roller 86 is provided near the outlet 83.
The casing 81 of the paper stock unit 14b is formed so as to be mountable near the return port 29 of the casing 11a of the base body unit 11.
It is further introduced into the casing 81 and placed on the bottom plate 84. The bottom plate 84 is considered so that the trailing edges of the sheets to be introduced are aligned. When a predetermined number of sheets are stocked, the bottom plate 84 is pressed against the sheet feeding roller 86 by a pressing means (not shown) in response to a sheet feeding command, and the sheet in contact with the sheet feeding roller 86 is fed one by one.

The paper fed from the outlet 83 is guided from the paper feed port 22 of the casing 11a of the base body unit 11 to a transfer position by the latent image carrier 1. When the leading edge at the time of introduction in the casing 81 is fed, the sheet is reversed and fed as a rear end. The sheet stock unit 14b is mainly used for double-sided image formation.

As the paper cassette 14, a unit configured to feed the paper from the entrance to the exit, with the front and back turned over, may be used.

This unit can be used, for example, for composite image formation in which several image forming apparatuses are superimposed on the same side of a sheet.

The cleaning unit 15 is, as shown in FIG. 13, a blade arranged so as to be in contact with the latent image carrier 1 at the time of mounting.
A main cleaning unit 15a provided at the entrance 92 of the casing 91 and a blade 93 (not shown) for sending the toner scraped from the latent image carrier 1 by the blade 93 to the back of the casing 91 such as a roller or a screw. It has a suitable feeding member. The casing 91 is formed as a toner container. When the toner is full, the entire casing 91 is replaced. If necessary, a separately removable container may be provided in the casing 91, the toner may be stored in the container, and only the container may be replaceable. The blade 93 is used to remove residual toner on the latent image carrier 1 after the transfer, and performs cleaning while the latent image carrier circulates several times, such as three to four times, when forming a multicolor image. There are times when they are not needed. At this time, the blade 93 is moved so as not to contact the latent image carrier 1.

Means for moving the blade 93 is not shown, but a known structure can be used and is provided in the casing 91.

The cleaning unit 15 may be built in the main cleaning unit 15a, but as shown in FIG. 14, another unit is formed as the auxiliary cleaning unit 15b to enable the initialization of the latent image carrier 1. Static neutralization lamp (QL) 95 and brush 96 that assists cleaning
In a casing 94. A charger or the like can be incorporated in this.
N, OFF, the brush 98 is moved back and forth between a position in contact with the latent image carrier 1 and a non-contact position.

The reading unit 17 can be composed of a latent image carrier reading unit 17a for reading a toner image on the latent image carrier 1, and a document reading unit 17b for reading a document image. As an example, a latent image carrier reading unit 17a is a lens that forms an illumination lamp 102 and reflected light from the latent image carrier 1 on a casing 101 as shown in FIG.
An optical system such as 104 and a circuit board 105 related to the image sensor are built in. As shown in FIG. 16, the document reading unit 17b includes a light source 114 for illuminating the document, a light source 114 for illuminating the document, and a reflection plate from the document. Light into an image sensor (CCD, etc.)
A structure in which an optical system 118 including a mirror 116, a lens 117, and the like for forming an image on the 115 and a circuit board 119 related to the imaging element 115 can be provided.

By using the document reading unit 17b, an image forming apparatus as a copying machine can be configured. Excluding the document reading unit 17b, an image forming apparatus as a printer that forms an image based on information from outside can be configured. Can be.

The operation of this apparatus is as follows. In the case of monocolor double-sided printing shown in FIG. 3, the latent image carrying belt 1 driven by the writing unit 12 is driven by a command from a control device built in the base body unit 11. An image is formed, and is developed by an original unit 13 of a corresponding color, for example, one of three developing units including developers of three colors of black, blue, and red, for example, a central blue developing unit 13, and supplied. The sheet is transferred to the sheet fed from the sheet cassette unit 14a, is fixed by the fixing unit 16, is inverted and makes a U-turn as shown in the example of FIG. 4, and is stocked in the sheet stock unit 14b from the return port. When a predetermined number of prints are completed, the latent image carrying belt 1 after the transfer is cleaned by the auxiliary cleaning unit 15a and the main cleaning unit 15b. The reading unit 17 can be used to read the toner adhesion pattern on the latent image carrying belt 1. The illumination lamp 102 is illuminated only during reading. The read information is fed back to other units in synchronism with the toner adhering pattern for the deviation between the thin lines and the adhering density. The pattern to be read by the reading unit is specially a latent image carrying belt 1.
Formed.

According to the next command, an image of another color is written on the latent image carrying belt 1 by the writing unit 12 to form a latent image, and the latent image is re-fed by the developing unit 13 of another color, for example, the top red. The transferred reading is fixed by the fixing unit 16 and discharged.

In the example shown in FIG. 5, a multicolor high-speed printing is made possible. For example, a yellow image is formed on the latent image carrying belt 1 by the first set of the writing unit 12 and the developing unit 13, and a subsequent set of the writing unit 12 is formed. And a developing unit 13, for example, a magenta image is formed in a superimposed manner, then a cyan image is similarly formed in a superposed manner, and a black image is further formed as required, and supplied from the paper feeding cassette unit 14a. The image of the latent image carrying belt 1 is transferred to the paper to be printed, and the transferred paper is fixed by the fixing unit 16 and discharged. The latent image carrier 1 after the transfer is cleaned in the same manner as in the example of FIG. 3 and the process for forming the next image is started. In this example, a full-color image is formed by one rotation of the latent image carrying belt 1.

In the example of FIG. 4, a space is formed between the uppermost developing unit 13 and the paper feed cassette unit 14a, and it is shown that another unit can be mounted.

It is also possible to select the number of units to be mounted and to form base units of different heights each containing a latent image carrying belt of a different length.

〔effect〕

According to the present invention, each unit can be replaced individually, the life of each unit can be extended to the maximum, the replenishment and replacement time of the supply part can be appropriately selected, and each unit operates in the best condition It is now possible to do that.

According to the present invention, the developing unit can be exchanged according to the print type such as mono-color or full-color, and can be appropriately adjusted according to the user's request, and the user himself can appropriately change the configuration.

According to the present invention, the image forming speed can be improved by the user himself / herself by purchasing additional writing units and rearranging the units.

According to the present invention, the performance can be expanded by rearranging some units, and it is not necessary to change all the devices, which is very advantageous for the user in terms of economy.

According to the present invention, the units are commonly used, the mass production effect is obtained, the cost can be reduced, the trouble can be dealt with for each unit, and the maintenance becomes easy.

[Brief description of the drawings]

FIG. 1 shows four types of color image formation, A, B,
FIG. 2 is a schematic diagram showing the configuration of each unit according to the present invention, FIG. 3 is a schematic diagram showing an example of a combination of each unit, and FIG. 4 shows the operation of the paper cassette. FIG. 5 is a schematic view showing another example of a combination of units, FIG. 6 is a perspective view of a base unit, FIG. 7 is a schematic block diagram of a control device, and FIG. 8 is a writing unit. FIG. 9 is a schematic view of another example of the writing unit, FIG.
10 is a schematic diagram of the developing unit, FIG. 11 is a schematic diagram of the paper cassette unit, FIG. 12 is a schematic diagram of the paper stock unit, FIG. 13 is a schematic diagram of the main cleaning unit, and FIG. 14 is an auxiliary cleaning unit. 15 is a schematic diagram of a latent image carrier reading unit, and FIG. 16 is a schematic diagram of a document reading unit. 11 Base unit 12 Writing unit 13 Developing unit 14 Paper unit 15 Cleaning unit 16 Fixing unit 17 Reading unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-102130 (JP, A) JP-A-59-111457 (JP, A) JP-A-60-230155 (JP, A) JP-A 60-230 237459 (JP, A) JP-A-62-71971 (JP, A) JP-A-62-141574 (JP, A) JP-A-1-306876 (JP, A) Japanese Utility Model Publication No. 58-121040 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21/18 B41J 29/00 G03G 15/01

Claims (4)

(57) [Claims] 1. A base unit containing a latent image carrier, a transfer unit and a control device, and a full-color to single-color image detachable from the base unit and forming a latent image based on image information on the latent image carrier. A writing unit having a built-in component related to a method arbitrarily selected from among the forming methods; and a detachable unit which is detachable from the base unit and is provided on the latent image carrier corresponding to the selected image forming method. A developing unit in which a member and a developer for developing the latent image are stored, and a cleaning unit which is detachable from the base unit and has a built-in member for cleaning the latent image carrier after transfer, A paper unit detachably attached to the base body unit and containing a unit for storing paper and a unit for feeding paper, and a member for fixing the paper after transfer are built in. An image forming apparatus, comprising a wearing unit. 2. The image forming apparatus according to claim 1, wherein a reading unit having a reading member for reading any one of the original and the latent image carrier is detachable from the base unit. 3. Two positioning pins are formed between the base body unit and each of the detachable units on one side, and two positioning holes are formed on the other side for engaging the positioning pins, respectively. 3. The image forming apparatus according to claim 1, wherein one of the positioning pin and the positioning hole is position-adjustable. 4. 4. The image forming apparatus according to claim 1, wherein a support member for supporting each removable unit is provided in a shelf shape on the base unit.