JP2003295573A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve user's convenience and the handleability of an apparatus by smoothly performing the exchanging work of a developing unit. <P>SOLUTION: The image forming apparatus is equipped with lighting switches 107Y, 107M, 107C and 107K disposed in the range of an apparatus main body covered with an external cover and corresponding to a plurality of developing units. When any of the switches 107Y, 107M, 107C and 107K is operated to be depressed, a CPU 121 actuates a motor 81 for driving a developing system so as to move the developing unit corresponding to the lighting switch operated to be depressed to a take-out position. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming technique for printers, copiers, facsimile machines and the like.

[0002]

2. Description of the Related Art Conventionally, a charged photoconductor is exposed by an exposing means to form an electrostatic latent image on the photoconductor, and toner is attached to the electrostatic latent image by developing means to form a toner image. However, an electrophotographic image forming apparatus is known in which this toner image is transferred onto a transfer paper to obtain a predetermined image. Particularly, as an apparatus capable of forming a color image, it is formed on a photoreceptor. An image forming apparatus is known in which the toner image is primarily transferred to an intermediate transfer medium and the toner image transferred to the intermediate transfer medium is secondarily transferred to a transfer paper.
In this image forming apparatus, when forming a color image,
For example, a toner image of a plurality of colors is sequentially formed on the photoconductor, and primary transfer is performed on the intermediate transfer medium for each formation of the toner image of each color, thereby forming a color toner image on which the toner images of the plurality of colors are superimposed on the intermediate transfer medium. Then, the color toner image is secondarily transferred to a transfer paper to obtain a color image. In the image forming apparatus configured as described above, it is possible to perform monochromatic printing by using a specific color among a plurality of colors, for example, black toner.

As this type of image forming apparatus, there is known an image forming apparatus provided with a rotary developing section in which a plurality of developing units respectively containing toners of different colors are arranged radially around a rotation axis. In this image forming apparatus, one of the plurality of developing units is arranged at a developing position facing the photoconductor by being driven to rotate about its rotation axis to develop the electrostatic latent image on the photoconductor. , Primary transfer to the intermediate transfer medium. Further, the rotary developing unit is rotationally driven to switch the developing unit, and the development with the toner of each color and the primary transfer are repeated to form a color toner image by superposing the toner images of a plurality of colors on the intermediate transfer medium. There is.

In the above conventional image forming apparatus, when the developing unit is replaced when the remaining amount of toner contained in the developing unit is almost exhausted, the rotary developing unit is rotated to preset the developing unit to be replaced. The developing unit is replaced after being moved to the taken-out position. In this case, when the outer cover provided on the main body of the apparatus is opened, the inner cover that opens and closes the outlet of the developing unit can be opened and closed.
A replacement instruction button for instructing the movement of the developing unit to the take-out position is provided.

[0005]

By the way, it is known that the above-mentioned conventional image forming apparatus is provided with one replacement instruction button. In this apparatus, the rotary developing unit rotates by one color each time the replacement instruction button is pressed. Therefore, depending on the position of the developing unit, it may be necessary to press the replacement instruction button several times to move the desired developing unit to the take-out position, and thus the usability is not good. Further, it is necessary to provide a window or the like for confirming whether or not the desired developing unit is arranged at the exchange position. Also, in that case, one developing unit must be moved to the take-out position, and after confirming that the developing unit is different from the desired one, the replacement instruction button must be operated again, and it takes time to replace the developing unit. It will be necessary.

The present invention has been made in view of the above,
It is an object of the present invention to provide an image forming apparatus having a plurality of developing units, which can smoothly replace the developing units and improve the convenience of the user and the usability of the apparatus.

[0007]

In order to achieve the above object, the invention according to claim 1 is provided movably in a plurality of developing units in which toners of different colors are accommodated, and in an apparatus main body, One of the plurality of developing units includes a unit holding unit that holds the plurality of developing units, and a unit driving unit that moves the unit holding units to move the arrangement positions of the plurality of developing units. In an image forming apparatus in which an electrostatic latent image is developed in a state where it is selectively placed at a developing position, the apparatus body is covered with an outer cover that can be opened and closed, and the outer cover of the apparatus body. An inner cover that is openable and closable in a range, an outlet of the developing unit that is provided in a range covered by the inner cover of the apparatus body, and the outer cover of the apparatus body. When a plurality of exchange instruction buttons operable from outside for instructing an exchange operation of each of the plurality of developing units provided in a range covered by the plurality of exchange instruction buttons and any of the plurality of exchange instruction buttons are operated, And unit movement control means for moving the developing unit corresponding to the operated replacement instruction button to the take-out position facing the take-out port by operating the unit driving means and moving the unit holding portion. I am trying.

According to this structure, a plurality of externally operable exchange instruction buttons for instructing the exchange operation of each of the plurality of developing units are provided within the range covered by the outer cover of the apparatus main body. By operating any one of the plurality of exchange instruction buttons, the developing unit corresponding to the operated exchange instruction button is moved to the ejection position facing the ejection port, and an instruction to move the desired development unit to the ejection position is given. This can be easily performed with a single button operation, which allows the development unit replacement work to be performed smoothly, thereby improving user convenience and device usability.

Further, the invention according to claim 2 is provided in a range covered by the outer cover of the apparatus main body and the life judging means for judging the life of each of the plurality of developing units, and the plurality of developing units are provided. A plurality of replacement display means respectively corresponding to the above, and a life display control means for driving the replacement display means corresponding to the developing unit of the plurality of replacement display means determined to be the life by the life determination means. Is characterized by.

According to this structure, a plurality of exchange display means corresponding to the plurality of developing units are provided in a range covered by the outer cover of the apparatus main body. Then, the lifespans of the plurality of development units are respectively determined, and the replacement display unit corresponding to the development unit that has been determined as the lifespan among the plurality of replacement display units is driven to open the outer cover and replace the development unit. When performing the work, since the life of the developing unit can be reconfirmed, the convenience of the user and the usability of the apparatus are improved.

Further, the plurality of replacement display means and the plurality of replacement instruction buttons corresponding to the same developing unit may be constituted by an illumination switch integrally formed with each other (claim 3).

According to this structure, since the plurality of replacement display means and the plurality of replacement instruction buttons respectively corresponding to the same developing unit are illumination switches integrally formed with each other, the number of parts is reduced. As a result, the size of the device can be reduced.

According to a fourth aspect of the present invention, permission display means for displaying permission to open the inner cover is provided in a range of the apparatus body covered by the outer cover, and the apparatus body is provided with the permission display means. It is provided in the range covered by the outer cover,
Prohibition display means for displaying prohibition of opening of the inner cover, and driving the permission display means when any of the plurality of developing units is stopped at the extraction position,
In other cases, it is characterized by further comprising permission prohibition display control means for driving the prohibition display means.

According to this structure, permission display means for displaying permission to open the inner cover and prohibition display means for displaying prohibition of opening the inner cover are provided in a range covered by the outer cover of the apparatus body. The permission display means is driven when any one of the plurality of development units is stopped at the take-out position, and the prohibition display means is driven otherwise, so that the development unit can be used for replacement work. This prevents an operator's erroneous operation and prevents a device failure or the like.

Further, the invention according to claim 5 is provided in a range covered by the outer cover of the apparatus main body, and displays a plurality of information indicating whether or not the plurality of developing units are attached to the unit holding portion. The unit display means and the mounting display control means for driving the unit display means corresponding to the developing unit mounted on the unit holding portion among the plurality of unit display means are further provided.

According to this structure, a plurality of unit display means for displaying the presence / absence of mounting of the plurality of developing units in the unit holding portion are provided in a range covered by the outer cover of the apparatus main body, and a plurality of unit display means are provided. By driving the unit display means of the unit display means corresponding to the developing unit attached to the unit holding portion, the outer cover is opened to replace the developing unit when the developing unit is replaced. Since reconfirmation can be performed, user convenience and device usability are improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the external appearance of a printer which is an embodiment of an image forming apparatus according to the present invention will be described with reference to FIGS. 1 is a perspective view showing the appearance of the printer, FIG. 2 is a perspective view showing a state in which an outer cover is opened in FIG. 1, and FIG. 3 is a perspective view showing a state in which an inner cover is further opened in FIG.

As shown in FIG. 1, this printer has a box-shaped device body 1 which is substantially rectangular parallelepiped.
Is a paper discharge unit 2 and an operation display panel 3 provided on the upper surface.
And an outer cover 5 provided on the side plate 4, and a paper feed cassette 6 is attached to the lower portion of the apparatus body 1.

In the area of the side plate 4 covered by the outer cover 5, as shown in FIG. 2, a developing unit replacement operation display portion 100, an inner cover 101, and a photoconductor unit take-out lever 102 are provided. A photoconductor unit outlet 103 is provided. Further, as shown in FIG. 3, an outlet 104 for exchanging the developing unit is formed in the area of the side plate 4 covered by the inner cover 101.

The operation display panel 3 is provided with a plurality of operation keys and a display section made of, for example, a liquid crystal display, receives operation instructions to the printer from the user, and displays messages to the user. . An outer cover sensor 5A (see FIG. 8) for detecting the opening / closing of the outer cover 5 and an inner cover sensor 101A (see FIG. 8) for detecting the opening / closing of the inner cover 101 are provided respectively, and the detection signal thereof is the CPU 121 (see FIG. 8). Refer to)). Development unit replacement operation display section 10
Zero will be described later.

Next, the configuration of the printer will be described with reference to FIGS. FIG. 4 is a diagram showing the internal configuration of the printer, FIG. 5 is a schematic diagram of the rotary developing section, FIG. 6 is a development view of the intermediate transfer belt, FIG. 7 is a diagram showing a developing unit replacement operation display section, and FIG. 8 is a book. FIG. 3 is a block diagram showing an electrical configuration of the printer.

This printer superimposes four color toners of yellow (Y), magenta (M), cyan (C), and black (K) to form a full-color image, for example, only black (K) toner. Is used to form a monochromatic image, and when a print command signal including an image signal is given from an external device such as a host computer, the engine unit 7
The respective units are controlled to print out an image corresponding to the image signal on the transfer paper 8 conveyed from the paper feed cassette 6.

The engine unit 7 is a photosensitive member unit 1.
0, a rotary developing unit 20, an intermediate transfer unit 30, a fixing unit 40, and an exposure unit 50. The photoconductor unit 10 includes a photoconductor 11, a charging unit 12, and a cleaning unit 13, and the rotary developing unit 20 includes
Yellow developing unit 2 containing yellow toner
Y, magenta developing unit 2M containing magenta toner, cyan developing unit 2 containing cyan toner
C, a black developing unit 2K containing black toner, and the like. The intermediate transfer unit 30 includes an intermediate transfer belt 31, a vertical synchronization sensor 32, a belt cleaner 33,
A gate roller pair 34, a secondary transfer roller 35, a photoconductor driving motor 36, and the like are provided. Above 7 units 1
Each of 0, 2Y, 2M, 2C, 2K, 30, 40 is configured to be detachable from the apparatus body 1.

The photoconductor 11 of the photoconductor unit 10 includes the seven units 10, 2Y, 2M, 2C, 2K, 30,
In the state in which 40 is attached to the apparatus main body 1, it rotates in the direction of arrow 9 by the photoconductor driving motor 36, and is in contact with the intermediate transfer belt 31, and this contact position is in the primary transfer portion 14. It is set. Around the photoconductor 11, along the rotation direction 9, a charging unit 12, a rotary developing unit 20, and a cleaning unit 13 are arranged.

The charging unit 12 is provided with a wire electrode to which a predetermined high voltage is applied, and the photosensitive member 1 is formed by corona discharge, for example.
The outer peripheral surface of No. 1 is uniformly charged, and has a function as a charging unit. The cleaning unit 13 is arranged immediately upstream of the charging unit 12 in the rotation direction 9 of the photoconductor 11 and downstream of the primary transfer unit 14, and the primary of the toner image from the photoconductor 11 to the intermediate transfer belt 31. The toner remaining on the outer peripheral surface of the photoconductor 11 after the transfer is scraped off by a cleaning blade to clean the surface of the photoconductor 11.

The exposure unit 50 is reflected by a laser light source 51 composed of, for example, a semiconductor laser, a polygon mirror 52 that reflects the laser light from the laser light source 51, a polygon motor 53 that rotationally drives the polygon mirror 52, and a polygon mirror 52. Lens unit 5 for focusing the laser light
4, a plurality of reflection mirrors 55, a horizontal synchronization sensor 56, etc. are provided. Is reflected by the polygon mirror 52,
The laser beam 57 emitted through the lens unit 54 and the reflection mirror 55 scans the surface of the photoconductor 11 in the main scanning direction (direction perpendicular to the paper surface of FIG. 4), and the laser light 57 corresponding to the image signal is scanned. An electrostatic latent image is formed on the surface of the photoconductor 11.
At this time, the horizontal synchronization sensor 56 obtains a synchronization signal in the main scanning direction, that is, a horizontal synchronization signal.

The polygon motor 53 is a polygon mirror 5.
2 is a preset rotation speed, for example 30,000 rp
It is driven to rotate at a high speed of m (revolutions / minute). For example, it has a configuration capable of high-speed rotation by an oil bearing, and when the rotation speed reaches the above-mentioned set rotation speed by starting the drive, the CPU
A ready signal is sent to 121. The exposure unit 50 is
It has a function as an exposure unit.

The rotary developing section 20 has a holding frame 22 fixed to a rotation shaft 21 at the center thereof, and the holding frame 22 has four color developing units 2Y, 2M, 2 and.
Holds C and 2K detachably. Each developing unit 2Y,
2M, 2C, and 2K are developing rollers 23Y and 23, respectively.
M, 23C, 23K, and each developing roller 23Y, 23
In the state where M, 23C, and 23K are arranged at the developing position where they abut on the photoconductor 11, toner of each color adheres to the electrostatic latent image on the photoconductor 11 to perform development.

Each of the developing units 2Y, 2M, 2C, 2K and the holding frame 22 has a guide rail (not shown) which is provided parallel to the rotary shaft 21 and engages with each other.
Each of the developing units 2Y, 2M, 2C, 2K can be drawn out through the outlet 104 in the direction of the rotation shaft 21 of the holding frame 22. Further, a new developing unit can be attached to the holding frame 22 by pushing it in the direction of the rotation shaft 21 of the holding frame 22 through the outlet 104.

Here, only when one of the developing units (here, the developing unit 2K) is arranged at the take-out position as shown in FIG. 5C, the developing unit is taken out through the take-out port 104, and A new developing unit can be installed after taking it out. The side plate 4 prevents the developing unit from being taken out while the developing unit is arranged at a position other than the taking-out position.
All the developing units 2Y, 2M, 2 are attached to the holding frame 22.
When C and 2K are mounted, they are arranged radially around the rotary shaft 21.

A developing system driving motor 81 is connected to the rotary shaft 21 via a rotary clutch 82. The developing system driving motor 81 is, for example, a stepping motor in this embodiment, and is connected to the developing shafts 23Y, 23M, 23C, and 23K in addition to the rotating shaft 21. When the rotary clutch 82 is turned on and the developing system driving motor 81 is driven in the normal direction, the holding frame 22 rotates, and the four developing units 2Y, 2M, 2C, 2
The arrangement position of K moves. On the other hand, with one developing unit placed at the developing position, the rotary clutch 82
When the developing system driving motor 81 is driven in the reverse direction with the switch off, the developing rollers 23Y, 23M, 23C and 23K rotate. 4 and 5, in the present embodiment, for example, the holding frame 22 rotates clockwise and the developing roller 23
Y, 23M, 23C and 23K rotate counterclockwise.

A holding frame 22 (rotary developing section 2) is provided on one end side of the rotary shaft 21 (front side of FIG. 5).
A position sensor 25 for detecting the standby position (home position) of 0) is provided. This position sensor 25
Is composed of, for example, a detection disk 251 fixed to one end of the rotary shaft 21 and a photo interrupter 252 in which a light emitting unit (for example, LED) and a light receiving unit (for example, photodiode) are arranged to face each other. The peripheral portion of the disk 251 is arranged so as to rotate in the gap between the light emitting portion and the light receiving portion of the photo interrupter 252.

With this configuration, when the slit formed in the peripheral portion of the detection disk 251 passes through the gap of the photo interrupter 252, the output signal from the photo interrupter 252 switches between low level and high level. And
Based on the change in the output signal level, the developing system driving motor 81 is stopped after driving by a predetermined driving pulse number set in advance, and the rotary developing section 20 is stopped at the standby position. When rotating from the standby position, the position sensor 2
The position of the holding frame 22 is determined based on the number of drive pulses of the developing system drive motor 81 from the time when the output signal level of No. 5 changes. FIG. 4 shows a state in which the black developing unit 2K is arranged in the developing position, FIG. 5 (A) shows a state in which the holding frame 22 is arranged in the standby position, and FIG. 5 (B) shows the yellow developing unit 2Y in the developing position. Placed state,
(C) shows a state in which the black developing unit 2K is arranged at the take-out position.

The configuration of the position sensor 25 is not limited to this, and a reflection type optical sensor may be used instead of the photo interrupter. Also, for example, the holding frame 2
A characteristic portion such as a protrusion may be formed on a part of the outer peripheral edge of 2, and the standby position may be detected by detecting this characteristic portion. In this case, the detection disk 25 is attached to the rotary shaft 21.
1 is not necessary, the size in the axial direction can be reduced, which is advantageous in reducing the size of the device.

Further, each developing unit 2Y, 2M, 2C,
The unit-side connector 26 is provided on each side surface of the 2K end
Y, 26M, 26C, and 26K are fixed, a main body side connector 27 is movably arranged on the apparatus main body 1, and when the holding frame 22 (rotary developing section 20) is arranged at the developing position, A unit-side connector fixed to the developing unit located one downstream in the rotation direction of the holding frame 22 of the developing unit at the developing position (see, for example, FIG. 5).
As shown in (B), when the yellow developing unit 2Y is at the developing position, one unit side connector 26K fixed to the black developing unit 2K on the downstream side thereof is arranged at a position facing the main body side connector 27. Is configured to.

Further, the unit side connectors 26Y, 26
M, 26C, 26K are EEPROMs 83Y, 83M,
It incorporates 83C and 83K (see FIG. 8). EEPR
The OMs 83Y, 83M, 83C and 83K are for storing various data regarding the developing units 2Y, 2M, 2C and 2K.

The connector drive motor 28 moves the main body side connector 27 in the contact and separation directions with respect to the rotary developing section 20, and is a unit side connector (in FIG. The main body side connector 27 is moved between the fitting position with the side connector 26K) and the separated position.

When the main body side connector 27 is moved toward the fitting position by the connector drive motor 28, the connector main body of the main body side connector 27 enters the concave portion of the unit side connector 26K, and at the fitting position, the male part of the unit side connector 26K is male. The terminal electrode (not shown) and the female terminal electrode (not shown) of the main body side connector 27 are electrically connected. As a result, the EEPROM (the built-in EEPROM of the unit side connector 26K in FIG. 5B) built into the unit side connector and the CPU 121 are electrically connected via both connectors, and data transfer is performed with the CPU 121. By performing this, detection of mounting of the developing unit, detection of a new product, life management, and the like are performed.

Two of the male terminal electrodes of the unit side connector 26K are connected to each other to form a so-called loopback wiring. In addition, the unit side connectors 26Y, 2
6M and 26C are similarly configured and each include a loopback wiring. As a result, in the CPU 121, the main body side connector 27 and the unit side connector 26Y,
It is possible to detect that the 26M, 26C, and 26K are properly fitted to each other.

Further, the apparatus body 1 has a holding frame 22.
A lock lever 29 is provided for fixing the lock lever at a predetermined position. The lock lever 29 urges the holding frame 22 in the direction of pressing the holding frame 22 by the elastic force of elastic means (not shown) such as a spring member, and the concave portion of the lock lever 29 and the convex portion of the holding frame 22 are engaged with each other. In the locked state (solid line in FIG. 5), the holding frame 22 is securely fixed at the standby position, the developing position and the take-out position. A lock release solenoid (not shown) that pulls against the elastic force of the spring member is connected to the lock lever 29. When the lock release solenoid is turned on, the lock lever 29 locks the holding frame 22. Is released, and the holding frame 2 is in the unlocked state (broken line in FIG. 5).
Two rotations are possible.

The developing bias in which the direct current component or the direct current component and the alternating current component are superposed on each other is the developing bias generating circuit 1.
The toner of the color is applied to the developing roller by the developing roller 14 and is attached to the electrostatic latent image on the surface of the photoconductor 11 from the developing unit located at the contact position (developing position) with respect to the photoconductor 11 to develop the toner. Rotary developing unit 20 (developing unit 2Y,
2M, 2C, 2K) have a function as developing means.

The holding frame 22 corresponds to the unit holding portion, and the developing system driving motor 81 corresponds to the unit driving means.

Intermediate transfer belt 3 of intermediate transfer unit 30
1 is wound around a tension roller 31A, a drive roller 31B, a tension roller 31C and a driven roller 31D. The tension roller 31A is for surely bringing the intermediate transfer belt 31 into contact with the photoconductor 11. The drive roller 31B is rotationally driven together with the photoconductor 11 by the photoconductor drive motor 36.

As shown in FIG. 6, the intermediate transfer belt 31 is an endless belt formed by joining substantially rectangular sheet bodies at a joint 71. In FIG. 6, the arrow 72 indicates the rotational drive direction, and the arrow 73 indicates the rotational axis direction.

This intermediate transfer belt 31 has a rotational axis of 7
3 has a projecting portion 74 provided on one end side (upper side in FIG. 6) of 3, and a transfer inhibition area 75 and a transfer permission area 76. The transfer prohibited area 75 is set in a range of predetermined dimensions on both sides of the seam 71 from one end to the other end in the rotation axis direction 73. Transfer permission area 76
Is a region other than the transfer inhibition region 75 and is set to a rectangular region excluding one end and the other end in the rotation axis direction 73, and the toner image is primarily transferred to the transfer permission region 76. The transfer permission area 76 has a size larger than the A3 size in the long side direction in the rotation drive direction 72, and the A3 size toner image 77 in the long side direction in the rotation drive direction 72 can be transferred. In this embodiment, the maximum toner image size that can be formed on the intermediate transfer belt 31 is set to A3 size.

A roller-shaped bias applying member (not shown) is in contact with the intermediate transfer belt 31, and a predetermined primary transfer bias is applied to this bias applying member. Then, by the primary transfer bias, the photoconductor 1
The toner image on No. 1 is primarily transferred to the intermediate transfer belt 31.

The vertical synchronization sensor 32 is composed of, for example, a photo interrupter having a light emitting portion (for example, LED) and a light receiving portion (for example, photodiode) arranged to face each other, and one end side of the rotating intermediate transfer belt 31 in the rotation axis direction 73. And detects the passage of the protrusion 74 and outputs a detection signal. The detection signal output from the vertical synchronization sensor 32 is used as a vertical synchronization signal that serves as a reference for image formation control by the engine control unit 120. The vertical synchronization sensor 32 is arranged in the vicinity of the driven roller 31D, whereby the intermediate transfer belt 3 is
It is possible to reduce the influence of the bending and the swinging of No. 1 and to stably detect the protruding portion 74.

The belt cleaner 33 is in contact with the intermediate transfer belt 31 by means of the cleaner separation / contact clutch (see FIG. 4).
The intermediate and solid lines) and the separated state (broken line in FIG. 4) are switchably arranged, and scrape off the residual toner on the intermediate transfer belt 31 in the contact state. The contact and separation of the belt cleaner 33 is performed on the transfer prohibited area 75 of the intermediate transfer belt 31.

The gate roller pair 34 is rotationally driven by the driving force of the conveying system driving motor 60 being transmitted when the gate clutch is turned on. The secondary transfer roller 35 is in contact with the intermediate transfer belt 31 (solid line in FIG. 4) and separated (broken line in FIG. 4) with the separation clutch for the secondary transfer roller.
Can be switched. The secondary transfer roller 35 is applied with a predetermined secondary transfer bias while being in contact with the intermediate transfer belt 31, and conveys the transfer paper 8 while the intermediate transfer belt 3 is being conveyed.
The toner image on No. 1 is secondarily transferred onto the transfer paper 8, and the contact position is set at the secondary transfer portion 37.

The fixing unit 40 includes a heating roller 41 and a pressure roller 42, and the transfer paper 8 is formed by the rollers 41 and 42.
The toner on the transfer paper 8 is heated and melted to be fixed on the transfer paper 8 while being conveyed, and has a function as a fixing unit.

A half-moon-shaped pickup roller 61 is provided upward from the front end of the paper feed cassette 6 (the right end in FIG. 4).
The feed roller pair 62 is disposed, and the gate roller pair 3
4, the secondary transfer roller 35 and the fixing unit 40 are sandwiched, and a conveyance roller pair 63 and a discharge roller pair 64 are further arranged to form a conveyance path of the transfer paper 8 (a chain line in FIG. 4). ing.

The pickup roller 61 is driven by a pickup solenoid. The feed roller pair 62, the gate roller pair 34, the secondary transfer roller 35, the heating roller 41 of the fixing unit 40, the conveyance roller pair 63, and the discharge roller pair 64 are the same conveyance system drive motor via the drive force transmission mechanism. It is connected to 60. The transport system driving motor 60 outputs a ready signal when it reaches a predetermined rotation speed. When the feed clutch is turned on, the feed roller pair 62 is rotationally driven by transmitting the driving force of the transport system driving motor 60. The transfer sheet 8 is formed by a pair of discharge rollers 64, and the sheet discharge unit 2 provided on the upper portion of the apparatus body 1.
Is discharged to.

In FIG. 7, the developing unit replacement operation display section 100 includes an opening prohibition display section 105, an opening permission display section 106, and illumination switches 107Y, 107M, 107.
Equipped with C and 107K. The open prohibition display section 105
This message is for indicating to the user that the opening operation of the inner cover 101 is prohibited, and a message (in this embodiment, for example, a hand over which the inner cover is opened is overlaid with an X mark) indicating that effect is displayed. In addition to the above, the red LED 108 is provided. The opening permission display unit 106 is for indicating to the user that the opening operation of the inner cover 101 is permitted, and is provided with a message (in this embodiment, for example, a picture of a hand opening the inner cover) indicating that. With green LED1
It is equipped with 09. Illumination switches 107Y, 107M,
Each of 107C and 107K is composed of a push button that can be pressed from the outside, and a button body of the push button has, for example, an LED built therein so that the push button can be turned on. Development unit replacement operation display section 1
The display control of 00 will be described later.

In FIG. 8, the main controller 110 is a CPU
111, an interface 112 for exchanging control signals with an external device, and an image memory 113 for storing an image signal given via the interface 112. The CPU 111 interfaces the print command signal including the image signal from an external device with the interface 112.
When received via the engine, the job data is converted into job data in a format suitable for the operation instruction of the engine unit 7 and sent to the engine control unit 120.

The engine control unit 120 includes a CPU 121,
The ROM 122 and the RAM 123 are provided. ROM
A CPU 122 stores a control program of the CPU 121, and a RAM 123 temporarily stores control data of the engine unit 7 and calculation results by the CPU 121. The CPU 121 is sent from an external device via the CPU 111. RAM 123 for the data related to the image signal
To store.

The CPU 121 receives a vertical synchronization signal Vsync from the vertical synchronization sensor 32 and a horizontal synchronization signal Hsync from the horizontal synchronization sensor 56 as input signals from the engine unit 7, and receives the outer cover sensor 5A, the inner cover sensor 101A, The detection signals are respectively received from the position sensors 25. Then, the CPU 121 controls the operation of each unit of the engine unit 7 based on these input signals and the control program.

That is, the CPU 121 sends a control signal to the motor drive circuit for driving the photoconductor driving motor 36 to synchronously rotate the photoconductor 11 and the intermediate transfer belt 31. Further, the CPU 121 sends a control signal to a motor drive circuit that drives the transport system drive motor 60,
The transfer paper 8 is controlled to be transferred from the paper feed cassette 6, and the transfer paper 8 is transferred at the same speed as the peripheral speed S1 of the intermediate transfer belt 31.

Further, the CPU 121 sends a control signal to a separation / engagement clutch drive circuit (not shown) for driving each separation / engagement clutch to separate and contact the belt cleaner 33 and the secondary transfer roller 35 with respect to the intermediate transfer belt 31. To control. Further, the CPU 121 receives the operation content of the operation key of the operation display panel 3 and controls the display content of the display unit.

Further, the CPU 121 sends a control signal to the developing bias generating circuit 124 to control the application of the developing bias. Further, the CPU 121 sends a control signal to the motor drive circuit 125 that drives the developing system drive motor 81, and also sends a control signal to the clutch drive circuit 126 that drives the rotary clutch 82 to hold the holding frame 22 and the developing roller. 23Y, 23M, 23C, 23
Control the rotational drive of K.

Further, the CPU 121 sends a control signal to a motor drive circuit (not shown) for driving the connector drive motor 28, and the unit side connectors 26Y, 26M, 2 are connected.
The fitting and separation of the 6C and 26K and the main body side connector 27 are controlled. At this time, the unit side connectors 26Y, 2
By the loopback wiring arranged on the 6M, 26C, and 26K, the CPU 121 allows the unit-side connector 26Y,
It is detected that the 26M, 26C and 26K and the main body side connector 27 are properly fitted to each other.

Further, the CPU 121 sends a control signal to a drive circuit (not shown) which drives a lock release solenoid (not shown), and stops the drive of the lock release solenoid to lock the holding frame 22 by the lock lever 29. Then, the lock release solenoid is driven to unlock the holding frame 22 by the lock lever 29.

Further, the CPU 121 counts the number of writing pixels of the electrostatic latent image by using the control signal sent to the laser light source 51, calculates the toner usage amount of each color based on the number of pixels, and the EEPROMs 83Y, 83M, 83C, 83K
Write the data on the amount of toner used to
By reading the stored contents of the EPROMs 83Y, 83M, 83C, and 83K, the attached developing units 2Y and 2Y
M, 2C, 2K new product detection and remaining life determination.

Further, the CPU 121 uses the inner cover sensor 1
The opening / closing of the inner cover 101 is determined based on the detection signal of 01A, and when the inner cover 101 is opened, the power supply to the developing system drive motor 81, the connector drive motor 28, and the unlock solenoid is shut off. Further, the CPU 121 determines whether the outer cover 5 is open or closed based on the detection signal of the outer cover sensor 5A, and when the outer cover 5 is opened, cuts off power supply to drive sources other than the above drive sources.

Further, the CPU 121 uses the developing unit 2
When it is determined that there is no remaining life of Y, 2M, 2C, and 2K, the fact is displayed on the operation display panel 3, and while the outer cover 5 is open, the illumination switches 107Y and 107M corresponding to the developing unit are displayed. , 107C, 107K are turned on.

Further, the CPU 121 controls the illumination switch 10
When any one of 7Y, 107M, 107C, and 107K is pushed by the user, the holding frame 22 is rotated and the developing units 2Y, 2M, corresponding to the switch are rotated.
Move 2C and 2K to the extraction position.

Further, the CPU 121 uses the developing unit 2
During a predetermined operation of the developing units 2Y, 2M, 2C, 2K, such as movement of Y, 2M, 2C, 2K to the take-out position, the red LED 108 is made to blink. In addition, the CPU 121
Turns off the red LED 108 and turns on the green LED 109 when any of the developing units 2Y, 2M, 2C and 2K is stopped at the take-out position. These L
The lighting control of the EDs 108 and 109 is performed while the outer cover 5 is open.

Illumination switches 107Y, 107M, 107
C and 107K correspond to exchange instruction buttons and exchange display means, the open prohibition display section 105 and the red LED 108 correspond to prohibition display means, the open permission display section 106 and the green LED 109 correspond to permission display means, and the CPU 121 is a unit. It corresponds to the movement control means, the life display control means, and the permission / prohibition display control means. ROM 122 and RA
M123 constitutes a memory unit, and this memory unit is EEPR.
A non-volatile memory such as an OM or another type of memory may be adopted.

Next, the operation of the printer will be described with reference to FIG. FIG. 9 is a timing chart showing the change over time of the state of each part of the engine unit 7.

When a print command signal including an image signal is given to the main control section 110 from an external device such as a host computer, the engine control section 120 causes each section of the engine section 7 to operate in response to the control signal from the main control section 110. Start operation. At this time, if the size of the transfer paper 8 loaded in the paper feed cassette 6 does not match the size instructed by the print command signal, a message prompting replacement of the paper feed cassette is displayed on the operation display panel 3. To do. In addition, in FIG.
Although the printer is provided with one sheet feeding cassette 6, the present invention is not limited to this, and a printer having a plurality of sheet feeding cassettes may be used.

Transfer paper 8 loaded in paper feed cassette 6
Is the same as the size instructed by the print command signal (or a plurality of paper feed cassettes includes a cassette that accommodates the transfer paper 8 of the size instructed by the print command signal). ), As shown in FIG. 9, first, the transport system drive motor 60 is turned on at time t1. Then, when the ready signal is output from the transport system driving motor 60 at time t2, the driving of the photoconductor driving motor 36 is started, the intermediate transfer belt 31 is driven at a predetermined peripheral speed S1, and the vertical synchronization signal is output. The Vsync is periodically output and the driving of the polygon motor 53 is started. Then, when the ready signal is output from the polygon motor 53 at time t3, it is effectively accepted from the next vertical synchronization signal Vsync, the surface of the photoconductor 11 is uniformly charged by the charging unit 12, and the surface of the photoconductor 11 is received. , An electrostatic latent image corresponding to the image signal is formed by the laser beam 57 from the exposure unit 50, and the electrostatic latent image is developed by the rotary developing unit 20 to form a toner image. Primary transfer is performed on the intermediate transfer belt 31 in the next transfer unit 14.

That is, the intermediate transfer belt 31 is rotated by the driving of the photoconductor driving motor 36, and the times t4, t5, and
The vertical synchronization signal Vsync is output at t6 and t7, respectively. A predetermined time T from the falling edge of each vertical synchronization signal Vsync
After one time, the image request signal Vreq is output, and upon the falling of the image request signal Vreq, the formation of the electrostatic latent image corresponding to the image signal is started and the developing bias is turned on.

Then, the developing units of the rotary developing section 20 are switched at times t4, t5, t6, and t7 so that toner images of respective colors are formed on the photoconductor 11 and sequentially primary-transferred onto the intermediate transfer belt 31. It During this time, the secondary transfer roller 35 is separated from the intermediate transfer belt 31, so that the toner images of the respective colors are superposed on the intermediate transfer belt 31. The developing bias is at time t4, t5, t
It is turned off after a predetermined time T2, which is predetermined by the transfer paper size, from the falling point of each vertical synchronization signal Vsync of 6 and t7. As a result, the toner images Y, C, M and K are superimposed on the transfer permission area 76 of the intermediate transfer belt 31. If the next print command signal is not input, K
After the development with toner is completed and the rotation of the developing roller 23K is stopped, the holding frame 22 is moved to the standby position.

On the other hand, the uppermost transfer paper 8 of the transfer paper stack loaded in the paper feed cassette 6 is taken out by the pickup roller 61, conveyed at a predetermined speed by the feed roller pair 62, and nipped by the gate roller pair 34. It Then, the gate clutch is turned on in synchronization with the toner image on the intermediate transfer belt 31, and the gate roller pair 3
The transfer paper 8 is conveyed from 4 to the secondary transfer portion 37.

Then, after a lapse of a predetermined time from the time t8 when the vertical synchronizing signal Vsync falls, the separation clutch for the secondary transfer roller is turned on, the secondary transfer roller 35 contacts the intermediate transfer belt 31, and Then, the application of the secondary transfer bias from the transfer bias generation circuit 116 to the secondary transfer roller 35 is turned on at a time t9 after a predetermined time from the time t8. As a result, the color toner image in which the toner images Y, C, M, and K that have been primarily transferred to the transfer permission area 76 of the intermediate transfer belt 31 are superimposed is transferred to the transfer paper 8.

The gate clutch is turned off after the transfer paper 8 is carried out, and the application time T3 of the secondary transfer bias is set in advance according to the size of the transfer paper 8. After the application of the secondary transfer bias is turned off, the separation clutch for the secondary transfer roller is turned on, and the secondary transfer roller 35 is separated from the intermediate transfer belt 31. Then, in the fixing unit 40, the toner image is fixed on the transfer paper 8 while the transfer paper 8 is being conveyed. The transfer paper 8 is further transported by the transport roller pair 63, and is discharged to the paper discharge unit 2 by the discharge roller pair 64.

After the image formation, if the next print command signal is not input, the charging unit 12 is turned off at time t10, which is the falling point of the vertical synchronizing signal Vsync, and the primary transfer bias is passed after a predetermined time from time t10. Is turned off, then
At a time t11, which is a predetermined time after the time t10, the photoconductor drive motor 36 starts decelerating, and at the time t12 when the photoconductor drive motor 36 stops, the laser light source 51 is turned off and the transport system drive motor 60 is generated. Is turned off. The polygon motor 53 is turned off at time t13, which is a preset standby time T4 (for example, T4 = 30 seconds in the present embodiment) from time t12.

Next, drive control of the developing unit replacement operation display section 100 will be described with reference to FIG. FIG. 10 is a flowchart showing an example of the drive control procedure.

First, it is judged whether or not the outer cover 5 is opened (# 10), and if it is closed (N in # 10).
O), when this routine is finished and the outer cover 5 is opened (YES in # 10), the red LED 108 blinks to give a warning that the inner cover 101 is not opened (# 1).
2).

Next, it is judged whether or not there is a developing unit that has reached the end of its life (# 14), and if it does not exist (# 14).
If NO in step 14), this routine ends. On the other hand, if there is a developing unit that has reached the end of its life (YES in # 14),
Illumination switch 107Y, 107M, 107C, 107K
Of these, the illumination switch corresponding to the developing unit that has reached the end of its life is turned on (# 16).

Next, the illumination switches 107Y and 107
It is determined whether or not the M, 107C, 107K pushing operation has been performed (# 18), and if not (N in # 18,
O), waits until the pushing operation is performed, and when the pushing operation is performed (YES in # 18), the holding frame 22 is rotationally driven, and the pushing operation is performed among the developing units 2Y, 2M, 2C, 2K. The developing unit corresponding to the illuminated switch starts moving toward the take-out position (# 20).

Then, it is judged whether or not the developing unit has reached the take-out position (# 22). If not (NO in # 22), the process stands by until the developing unit reaches the take-out position. (YES in # 22), red LE
D108 is turned off (# 24), and the green LED 109 is turned on to indicate that opening of the inner cover 101 is permitted (# 26).

As described above, according to this embodiment, the illumination switches 107Y, 107M, 107C and 107K corresponding to the developing units 2Y, 2M, 2C and 2K are provided, and the illumination switches 107Y, 107M, 107C and 10K are provided.
When any of 7K is pressed, the developing unit 2Y,
Since the corresponding developing unit of 2M, 2C and 2K is moved to the take-out position, the operability of the apparatus can be improved and the replacement work of the developing unit can be smoothly performed, which improves the convenience of the user. At the same time, the usability of the device can be improved.

Further, according to this embodiment, the illumination switch 1 is provided in the vicinity of the inner cover 101 within the range covered by the outer cover 5.
07Y, 107M, 107C, 107K are provided, and it is determined whether or not the developing units 2Y, 2M, 2C, 2K are at the end of life, and the illumination switch corresponding to the developing unit that is at the end of life is turned on. Therefore, the user can reconfirm the developing unit to be replaced immediately before the replacement operation, which improves the convenience of the user and improves the usability of the apparatus.

Further, according to the present embodiment, the opening prohibition display portion 105, the red LED 108, the opening permission display portion 106 and the green LED 109 are arranged in the vicinity of the inner cover 101 within the range covered by the outer cover 5, and the development is performed. The red LED 108 is blinked while the unit is moving, and the green LED 109 is turned on when the developing unit is stopped at the take-out position. Therefore, a malfunction of the apparatus due to an erroneous operation of opening and closing the inner cover 101 by the user can be prevented. Can be prevented,
As a result, the usability of the device can be improved and the convenience of the user can be improved.

Further, according to the present embodiment, since the illumination switches 107Y, 107M, 107C and 107K are provided and also serve as the replacement instruction button and the replacement display means, the size of the apparatus and the number of parts can be reduced. be able to.

The present invention is not limited to the above embodiment, and various changes can be made to the above without departing from the spirit of the invention. For example, the following modification (1) )-(5) can be adopted.

(1) In the above embodiment, the illumination switch 1
07Y, 107M, 107C, 107K are used as the exchange instruction button and the exchange display means, but the present invention is not limited to this, and the exchange instruction button including an operation switch and the exchange display means including an LED are separately provided. It may be provided.

(2) Illumination switches 107Y, 107M,
Whether or not the developing unit is mounted may be displayed by 107C and 107K. For example, the CPU 121
When the outer cover 5 is opened, the illumination switches 107Y, 1
Of 07M, 107C, 107K, the illumination switch corresponding to the developing unit mounted on the holding frame 22 is turned on. In this mode, the illumination switches 107Y, 10
7M, 107C and 107K correspond to unit display means, and the CPU 121 corresponds to mounting display control means. According to this aspect, it is possible to reconfirm whether or not the developing unit is mounted, so that the convenience of the user can be further improved.

In this embodiment, the illumination switch 107
Of the Y, 107M, 107C, and 107K, the illumination switch corresponding to the developing unit that has reached the end of life has the same effect as that of the above-described embodiment, for example, by making it blink. In this case, the illumination switches 107Y, 10
The 7M, 107C, and 107K can also be used as unit display means and replacement display means, and do not cause a situation in which the size of the device is increased due to an increase in the number of parts.

(3) The state where the remaining amount of toner accommodated in the developing unit is low (near end) and the state where toner is almost exhausted (end) are respectively determined, and the respective states are illuminated by the illumination switches 107Y and 107M. 107C, 10
You may make it distinguishably display by 7K.

In this case, for example, the illumination switch 107Y,
Of the 107M, 107C, and 107K, the illumination switch corresponding to the near-end developing unit may be blinked, and the illumination switch corresponding to the end developing unit may be constantly turned on. Further, blinking and constant lighting may be set in reverse.

According to this aspect, when the end developing unit is replaced, the near-end developing unit can be replaced at the same time, and the operation can be selected according to the user's request, thereby improving the convenience of the user. can do.

(4) In the above embodiment, the intermediate transfer belt 31 having the seam 71 is used as the image bearing member, but the present invention is not limited to this. For example, a seamless intermediate transfer belt or an intermediate transfer drum may be used.

(5) In the above embodiment, a printer that prints an image provided by an external device such as a host computer on a transfer paper is used for explanation, but the present invention is not limited to this, and a copying machine or a facsimile is used. The present invention can be applied to a general electrophotographic image forming apparatus including an apparatus.

[0095]

As described above, according to the first aspect of the invention, a plurality of externally operable exchange instruction buttons for instructing the exchange operation of each of the plurality of developing units are provided on the outer cover of the apparatus main body. Since it is provided in the covered range, by operating any of the plurality of exchange instruction buttons, the developing unit corresponding to the operated exchange instruction button moves to the ejection position facing the ejection opening,
You can smoothly replace the development unit,
The convenience of the user and the usability of the device can be improved.

According to the second aspect of the present invention, a plurality of replacement display means corresponding to the plurality of developing units are provided in a range covered by the outer cover of the apparatus main body, and the life of the plurality of developing units is reduced. Of the plurality of replacement display means, the replacement display means corresponding to the developing unit determined to have reached the end of life is driven, so that when the developing unit is replaced by opening the outer cover, It is possible to reconfirm a certain developing unit and improve the convenience of the user and the usability of the apparatus.

Further, according to the third aspect of the invention, the plurality of exchange display means and the plurality of exchange instruction buttons respectively corresponding to the same developing unit are constituted by the illumination switches integrally formed with each other. Therefore, the device can be downsized by reducing the number of parts.

According to the invention of claim 4, the permission display means for displaying permission to open the inner cover and the prohibition display means for displaying prohibition of opening the inner cover are covered with the outer cover of the apparatus body. The developing unit is provided in a range so that the permission display means is driven when any of the plurality of developing units is stopped at the take-out position, and the prohibition display means is driven otherwise. It is possible to prevent an erroneous operation by the user in the replacement work, and prevent a device failure or the like.

According to the fifth aspect of the invention, a plurality of unit display means for displaying the presence / absence of attachment of the plurality of developing units to the unit holding portion are provided in a range covered by the outer cover of the apparatus main body. Every other, since the unit display means corresponding to the developing unit attached to the unit holding portion among the plurality of unit display means is driven, when the outer cover is opened and the developing unit is replaced,
The installed developing unit can be reconfirmed, and the convenience of the user and the usability of the apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an external appearance of a printer which is an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a perspective view showing a state where an outer cover is opened in FIG.

FIG. 3 is a perspective view showing a state where the inner cover is further opened in FIG.

FIG. 4 is a diagram showing an internal configuration of the printer.

FIG. 5 is a schematic view of a rotary developing unit.

FIG. 6 is a development view of an intermediate transfer belt.

FIG. 7 is a diagram showing an operation display unit for developing unit replacement.

FIG. 8 is a block diagram showing an electrical configuration of the printer.

FIG. 9 is a timing chart showing changes over time in states of various parts of the engine unit.

FIG. 10 is a flowchart illustrating an example of a drive control procedure of a developing unit replacement operation display unit.

[Explanation of symbols]

1 Device Main Body 5 Outer Cover 20 Rotary Developing Sections 2Y, 2M, 2C, 2K Developing Unit 21 Rotating Shaft 22 Holding Frame (Unit Holding Section) 81 Developing System Driving Motor (Unit Driving Means) 101 Inner Cover 105 Opening Prohibition Display Section ( Prohibition display means 106 Open permission display section (permission display means) 107Y, 107M, 107C, 107K Illumination switch (replacement instruction button, exchange display means) 108 Red LED (prohibition display means) 109 Green LED (permission display means) 120 Engine Control unit 121 CPU (unit movement control means, life display control means, permission / prohibition display control means, mounting display control means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 21/00 510 G03G 21/00 510 512 512 512 16/16 15/00 554 (72) Inventor Ken Yoshizuka Nagano 3-5 Yamato 3-chome, Suwa Prefecture, Japan Seiko Epson Corporation F-term (reference) 2H027 DA27 GA12 GA28 GA29 GA30 GA54 GB05 HB01 HB06 HB13 HB18 2H077 BA01 BA09 BA10 GA04 GA13 2H171 FA02 FA04 FA13 GA11 GA12 JA06 KA22 KA16 KA05 KA16 QA02 QB34 QB38 2H300 EA01 EA07 EA08 EA10 EA12 EA13 EA16 EA17 EA18 EB09 EB12 EB23 EG03 EH16 EJ07 EJ09 EJ15 EJ20 EJ21 EJ25 EL01 GG33 QQ10 QQ13 QQ16 QQ35 RR19 TT04 RR24 TT

Claims (5)

[Claims] 1. A plurality of developing units respectively containing toners of different colors, a unit holding unit movably provided in the apparatus main body for holding the plurality of developing units, and a unit holding unit that moves the unit holding unit. A unit driving unit that moves the arrangement positions of the plurality of developing units, and the electrostatic latent image is developed in a state where one of the plurality of developing units is selectively arranged at the developing position. In the image forming apparatus, an outer cover that is openably and closably provided on the apparatus body, an inner cover that is openably and closably provided in a range covered by the outer cover of the apparatus body, and an inner cover of the apparatus body. Of the developing unit provided in a range covered by the outer cover and the plurality of developing units provided in a range covered by the outer cover of the apparatus main body. A plurality replacement instruction button operable from the outside for instructing over operation, when any one of the plurality of replacement instruction button is operated,
Unit movement control means for moving the developing unit corresponding to the operated replacement instruction button to the take-out position facing the take-out port by operating the unit driving means and moving the unit holding portion. A characteristic image forming apparatus. 2. A life determining means for determining the life of each of the plurality of developing units, and a plurality of replacement displaying means provided in a range covered by the outer cover of the apparatus main body and corresponding to each of the plurality of developing units. The life display control means for driving the replacement display means corresponding to the developing unit judged to have reached the end of life by the life judgment means among the plurality of replacement display means. Image forming device. 3. The plurality of replacement display means and the plurality of replacement instruction buttons, each corresponding to the same developing unit, are illumination switches integrally configured with each other. The image forming apparatus described. 4. A permission display unit provided in a range covered by the outer cover of the apparatus main body, for displaying permission to open the inner cover, and provided in a range covered by the outer cover of the apparatus main body. , A prohibition display means for displaying prohibition of opening of the inner cover, and driving the permission display means when any one of the plurality of developing units is stopped at the take-out position, and otherwise. A permission / prohibition display control means for driving the prohibition display means is further provided.
The image forming apparatus according to any one of 3 above. 5. A plurality of unit display means, provided in a range covered by the outer cover of the apparatus main body, for displaying whether or not the plurality of developing units are attached to the unit holding section, and a plurality of the plurality of unit display means. 5. The mounting display control means for driving a unit display means corresponding to the developing unit mounted on the unit holding part among the unit display means, further comprising: a mounting display control means. Image forming apparatus.