JP2006153931A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which allows a stopped process cartridge to be replaced in such a state that process cartridges other than a black process cartridge are separated from a belt-like transfer means, if a stop condition of process cartridges is satisfied. <P>SOLUTION: In the image forming apparatus, a plurality of process cartridges which have photoreceptor drums as electrostatic latent image carriers and developing means for developing electrostatic latent images, integrally constituted therein and are attachable to and detachable from the image forming apparatus are disposed around the belt-like transfer means. The image forming apparatus has a color mode of forming a multi-color image and a monochromatic color mode for forming a black image. In the monochromatic color mode, process cartridges other than the black process cartridge are separated from the belt-like transfer means, and a stopped process cartridge is replaced in such a state that the process cartridges other than the black process cartridge are separated from the belt-like transfer means, if the stop condition of process cartridges is satisfied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium such as an electrophotographic copying machine or an electrophotographic printer.

  As one type of full-color image forming apparatus, a tandem full-color image forming apparatus in which process cartridges containing magenta, cyan, yellow, and black color developers are arranged along a paper conveyance belt or intermediate transfer belt has been put into practical use. ing.

  In such a tandem full-color image forming apparatus, mono-color image formation and full-color image formation are switched, that is, image formation is performed using only a process cartridge containing a black developer at the time of mono-color image formation. There is an image forming apparatus that does not use a process cartridge of the above color.

  Patent Document 1 discloses a configuration in which the transfer material belt is separated from the photosensitive drum of a color other than black by partially moving the transfer material conveyance belt, and Patent Document 2 discloses an intermediate transfer belt. A spaced configuration is shown. With this configuration, the color process cartridge can be deactivated during mono-color image formation, and consumption of the process cartridge can be suppressed.

  On the other hand, not only a full-color image forming apparatus but also a special sequence may be added when a new product is detected during process cartridge replacement. As shown in Patent Document 3, a process of positively applying a lubricant to the photosensitive drum of a new process cartridge, and as shown in Patent Document 4, a toner sealing seal is automatically wound on the new process cartridge. There is a rotational drive process to take.

JP-A-9-146383 JP 2001-242680 A JP 2002-343861 A JP 2001-056604 A

  However, by separating the transfer member from the photosensitive drum, image formation is performed using only the process cartridge containing the black developer during monocolor image formation, and the process cartridges of other colors are not used. In the tandem type full-color image forming apparatus, there is no description regarding a specific operation when the process cartridge is replaced. In particular, there is a demand for a specific method for suppressing the consumption of other process cartridges when a new process cartridge is inserted.

  Therefore, a first object of the present invention is to replace a stopped process cartridge while the process cartridge other than black is separated from the belt-shaped transfer means when the process cartridge stop condition is satisfied. An object is to provide an image forming apparatus.

  A second object of the present invention is to provide an image forming apparatus capable of suppressing the consumption of process cartridges other than those that have been replaced.

  A third object of the present invention is to provide an image forming apparatus capable of suppressing the consumption of process cartridges other than black.

  To achieve the above object, according to a first aspect of the present invention, a photosensitive drum, which is an electrostatic latent image carrier, and a developing unit for developing an electrostatic latent image are integrally configured and attached to and detached from an image forming apparatus. In an image forming apparatus in which a plurality of possible process cartridges are arranged around a belt-shaped transfer unit, there are a color mode for forming a multicolor image and a monocolor mode for forming a black image. The non-black process cartridge and the belt-shaped transfer unit are separated from each other. When the process cartridge stop condition is satisfied, the non-black process cartridge and the belt-shaped transfer unit are separated and the stopped process cartridge is stopped. It is characterized by exchanging.

  According to a second aspect of the present invention, there are provided a plurality of process cartridges that are configured integrally with a photosensitive drum that is an electrostatic latent image carrier and a developing unit that develops the electrostatic latent image, and that can be attached to and detached from the image forming apparatus. In the image forming apparatus arranged around the belt-shaped transfer unit, there are a color mode for forming a multicolor image and a monocolor mode for forming a black image. In the monocolor mode, a process cartridge other than black is used. The belt-like transfer means is separated, and when the stop condition for the process cartridge other than black is satisfied, the stopped process cartridge is replaced with the process cartridge other than black and the belt-like transfer means being separated. The rotation of the process cartridge other than the belt-shaped transfer means and the replaced process cartridge is stopped, and the replaced process cartridge And performing the rotational drive during the period established.

  According to a third aspect of the present invention, there are provided a plurality of process cartridges that are integrally configured of a photosensitive drum that is an electrostatic latent image carrier and a developing unit that develops the electrostatic latent image and that can be attached to and detached from the image forming apparatus. In the image forming apparatus arranged around the belt-shaped transfer means, there are a color mode for forming a multicolor image and a monocolor mode for forming a black image. In the monocolor mode, a process cartridge other than black is used. When the black process cartridge stop condition is satisfied, the black process cartridge is replaced with the non-black process cartridge and the belt-shaped transfer unit separated from each other. The rotation drive at the initial installation of the black process cartridge is performed in a state in which the rotation drive of other process cartridges is stopped. That.

  According to the present invention, when the stop condition of the process cartridge is satisfied, the stopped process cartridge is replaced while the non-black process cartridge and the belt-shaped transfer unit are separated from each other. Can be suppressed.

  In addition, when the stop condition of the process cartridge other than black is satisfied, the stopped process cartridge is replaced with the process cartridge other than black being separated from the belt-like transfer means, and the belt-like transfer means and the replacement are not performed. Since the rotational drive of the replaced process cartridge is stopped when the process cartridge rotational drive is stopped, only the minimum necessary rotational drive can be performed and consumption of the process cartridge can be suppressed. .

  Further, when the stop condition for the black process cartridge is satisfied, the black process cartridge is replaced with the non-black process cartridge and the belt-shaped transfer unit separated from each other, and the rotation drive of the non-black process cartridge is stopped. In this state, since the black process cartridge is rotated at the time of initial installation, only the minimum necessary rotation drive can be performed, and consumption of the process cartridge can be suppressed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, in the full-color image forming apparatus according to the present embodiment, the process cartridges 8M, 8C, 8Y, and 8K as the first, second, third, and fourth image forming units are arranged in a substantially vertical direction ( It has a structure that is stacked in the direction of gravity). Each of the process cartridges 8M to 8K forms magenta, cyan, yellow, and black images. The process cartridges 8M to 8K have the same configuration, and are photosensitive drums 9M, 9C, 9Y, and 9K that are image carriers, chargers 10M, 10C, 10Y, and 10K that are charging units, and for developing latent images. The developing sleeves 12M1, 12C1, 12Y1, and 12K1 are provided as developer carriers that accommodate the developers (toners) of the above-described colors and carry the developers on the surfaces thereof and are arranged corresponding to the photosensitive drums 9M to 9K. The developing devices 12M, 12C, 12Y, and 12K as the developing means and the cleaning blades 14M, 14C, 14Y, and 14K are integrated in each color. Exposure units 11M, 11C, 11Y, and 11K are provided on the main body side.

  In the present embodiment, the developing devices 12M, 12C, 12Y, and 12K are of a non-contact developing method, and the developing sleeves 12M1, 12C1, 12Y1, and 12K1 that are developing carriers of the developing devices 12M to 12K are opposed to each other. A developing bias in which a rectangular AC voltage and a DC voltage are superimposed between the photosensitive drums 9M to 9K and the developing sleeves 12M1 to 12K1 during development are held with a gap of about 300 μm from the photosensitive drums 9M to 9K. Is applied.

  The developing devices 12M to 12K that store the respective color toners are provided with 19C1, 19C2, 19Y1, 19Y2, 19K1, and 19K2 with a pair of transparent windows 19M1 and 19M2. The presence / absence of the developer in the developer container is determined by whether or not the light from the light emitting sources 22M, 22C, 22Y, and 22K provided in the main body is detected by the light receivers 23M, 23C, 23Y, and 23K. Detect.

  A transfer conveyance belt 7 constituting a transfer material carrying / conveying member that carries and conveys the transfer material 1 is disposed along each of the process cartridges 8M to 8K. The transfer conveyance belt 7 is stretched around a driving roller 5, a driven roller 6 and a belt stretching roller 20 which are belt driving means, and is driven to rotate in the direction indicated by an arrow A. The transfer units 13M, 13C, 13Y, and 13K are arranged to face the photosensitive drums 9M to 9K with the transfer conveyance belt 7 interposed therebetween. The transfer conveyance belt 7 has the driving roller 5 as a fulcrum, the transfer device 13K does not move, and the driven roller 6, the belt stretching roller 20, and the transfer devices 13M, 13C, and 13Y swing, whereby the photosensitive drums 9M, 9C, Separated from 9Y.

  FIG. 2 is a schematic view of a lubricant application device. By rotating the application brush 25M in contact with the photosensitive drum 9M, zinc stearate 26M as a lubricant is applied to the surface of the photosensitive drum 9M.

  Each of the process cartridges 8M to 8K is equipped with memory 27M, 27C, 27Y, and 27K as storage means, and holds that the process cartridge is new as information. Of course, when the process cartridge is used, this information can be rewritten.

  First, the case where a full-color image is formed will be described with reference to FIG.

  In response to an image formation request signal from the host 24, the image forming apparatus causes the preparatory rotation of the laser scanners that are the exposure units 11 </ b> M to 11 </ b> K, the preparatory rotation of the photosensitive drums 9 </ b> M to 9 </ b> K and the transfer conveyance belt 7, and the temperature adjustment rotation of the fixing unit 15. In addition, the recording paper 1 as a transfer material in the paper feeding unit 2 is taken out one by one by the pickup roller 16 and temporarily held by the registration roller 17.

  In the first process cartridge 8M, when the photosensitive drum 9M is uniformly charged by the charger 10M, a laser beam corresponding to magenta image information is irradiated to form an electrostatic latent image. The magenta toner of the developing device 12M is transferred to the electrostatic latent image by the developing bias, and a magenta toner image is formed on the photosensitive drum 9M.

  On the other hand, the recording paper 1 is timed with the magenta toner image on the photosensitive drum 9M, passes through the registration roller 17, is fed to the transfer conveying belt 7 through the paper passing path 4, and is adsorbed as an adsorbing means. The transfer conveyance belt 7 is adsorbed and supported by the action of the roller 18. Further, the transfer conveyance belt 7 is rotated and conveyed to the transfer portion T1, and the magenta toner image is transferred onto the recording paper 1 by the action of the transfer device 13M.

  Also in the second to fourth process cartridges 8C, 8Y, and 8K, the cyan toner image, the yellow toner image, and the black toner image are respectively transferred to the photosensitive drums 9C, 9Y, and 9K in the same manner as the first process cartridge 8M. As the recording paper 1 is conveyed by the transfer conveyance belt 7 to the transfer portions T2, T3, T4 of the second to fourth process stations 8C, 8Y, 8K, the transfer devices 13C, 13Y, 13K. As a result of the above, the toner images of the respective colors are overlaid and transferred.

  The recording paper 1 onto which the four color toner images have been transferred in the fourth process cartridge 8K at the most downstream side is conveyed to the fixing unit 15, where the toner image is fixed and conveyed to the discharge unit 3.

  After the transfer, each of the photosensitive drums 9M to 9K has the residual toner removed by the cleaning blades 14M to 14K and is used for the next image formation, while the image forming apparatus rotates the exposure units 11M to 11K, and the photosensitive drum 9M. ˜9K, the rotation of the transfer conveyance belt 7 and the rotation driving of the fixing device 15 are stopped.

  Next, the case where image output, that is, image formation is performed only by the most downstream fourth process cartridge 8K will be described with reference to FIG. Hereinafter, this image forming method is referred to as a mono color mode.

  When image output is performed only with the fourth process cartridge 8K on the most downstream side, the photosensitive drums 9M to 9Y of the first to third process cartridges 8M, 8C, and 8Y, which are color cartridges on the upstream side, and developing units 12M to 12C. Stop driving. Specifically, the rotational driving of the developing sleeves 12M1 to 12Y1 is stopped. Since the developing devices 12M to 12K of the present embodiment employ the non-contact developing method as described above, the developing sleeves 12M1 to 12K1 are connected to the photosensitive drums 9M to 9K regardless of whether the image is output or not. There is no rubbing.

  FIG. 4 is a control block diagram of the present embodiment. Since the process cartridges 8M, 8C, 8Y, and 8K have one configuration, the first process cartridge 8M will be described as an example. One control unit 37 is provided in the image forming apparatus.

  The photosensitive drum 9M and the developing device 12M are driven by a driving motor 34 which is a driving unit via a clutch 36 capable of driving transmission. Drive control of the drive motor 34 and the clutch 36 is performed by a control unit 37 that is a control unit. That is, in the present embodiment, the control unit 37 can select the process cartridges 8M to 8K used for image formation, and for the process cartridges not used for image formation, the clutch 36 releases the drive transmission to the developing device. . One drive motor 34 may be provided for each of the process cartridges 8M to 8K, or one drive motor 34 may be provided for each of the plurality of process cartridges. .

  FIG. 5 is a control block diagram of the transfer conveyance belt 7 of the present embodiment. The control unit 43 may be the same as the control unit 37 described above, and one control unit 43 is provided in the image forming apparatus.

  The transfer conveyance belt 7 is driven to rotate by driving the drive roller 5 by the drive motor 40. The rotation of the drive motor 40 is transmitted to the swing gear 42 via a clutch 41 capable of driving transmission, and a full color position (a position where the photosensitive drums 9M to 9K abut) and a monocolor position (the photosensitive drums 9M to 9Y). Rock position). Drive control of the drive motor 40 and the clutch 41 is performed by a control unit 43 that is a control unit. As described above, the separating operation of the transfer conveyance belt 7 from the photosensitive drums 9M to 9Y is performed through the rotational drive of the transfer conveyance belt 7, so in this embodiment, the photosensitive drums 9M to 9Y are stopped. The driving of the photosensitive drums 9M to 9Y is stopped after being separated from the conveyance belt 7 so as not to rub against the conveyance belt 7 later.

  The operation of the image forming apparatus according to the present embodiment will be described with reference to FIG.

  When a request for full-color image formation is issued from the host and “out of toner” is detected in the first to third process cartridges 8M, 8C, and 8Y that are color cartridges during the above-described full-color image formation operation, the rear end of the recording paper 1 Immediately passes through the respective transfer portions T3 of the third process cartridge 8Y by the transfer conveyance belt 7, and immediately enters the state of receiving the action of the transfer device 13K only at the transfer portion T4 of the fourth process cartridge 8K. By immediately controlling the clutch 41 by the provided control unit 43, the transfer / conveying belt 7 is separated from the full color position (position where it contacts the photosensitive drums 9M to 9K) from the monochromatic position (photosensitive drums 9M to 9Y). Position).

  At the same time as the photosensitive drums 9M to 9Y and the transfer / conveying belt 7 are separated from each other, drive control is performed by the control unit 37 serving as a control unit, and the rotational drive of the process cartridges 8M to 8C is stopped. By quickly transitioning to a state in which monocolor image formation is possible in this way, the process cartridge that is not used for image formation is consumed in the case where the photosensitive drum and others are stopped while being rotationally driven at the full color position. Can be suppressed. In this state, the process proceeds to the post-rotation operation of the black process cartridge, stops the image forming apparatus, and notifies the host that only mono-color image formation is possible.

  In this state, the image forming apparatus according to the present embodiment can form a monocolor image using only the fourth process cartridge 8K.

  Next, when the user replaces one of the first to third process cartridges 8M, 8C, and 8Y that has become “out of toner”, the transfer conveyance belt 7 has the photosensitive drums 9M to 9Y. The monochromatic position, which is a position that is separated from each other, is maintained. The image forming apparatus receives information that “the process cartridge is new” from the memory 27X that is a storage unit mounted on the process cartridge 8X, and zinc stearate that is a lubricant on the surface of the photosensitive drum 9X that is a new product sequence. In order to positively apply 26X, the photosensitive drum 9X is rotationally driven for a predetermined time. At this time, the controller 37 drives only the photosensitive drum 9X and does not drive other color cartridges. In addition, the fourth process cartridge 8K and the transfer conveyance belt 7 are not driven.

  When the process cartridge is exchanged at the monocolor position (position away from the photoconductor drums 9M to 9Y), if the photoconductor drum is rotated only by stopping the transfer conveyance belt and the exchanged process cartridge is rotated, the difference in peripheral speed between the two causes If the photosensitive drum is rotated only in the process cartridge that has been replaced by rotating the transfer / conveying belt, the flaw defect may occur due to the difference in the peripheral speed between the transfer / conveying belt and the photosensitive drum. If the transfer conveyance belt is rotated and the photosensitive drums of all the process cartridges are rotated, unnecessary problems of rotating the photosensitive drums in the process cartridges other than the exchanged cartridges will be eliminated, and the above-described problems that may be consumed can be solved. .

  It goes without saying that with the above configuration, even in an image forming apparatus using an intermediate transfer belt, consumption of a process cartridge that is not used can be suppressed. In the present embodiment, the developing sleeves 12M1 to 12K1 and the photosensitive drums 9M to 9K have been described using a non-contact developing method. However, the developing sleeves 12M1 to 12K1 and the photosensitive drums 9M to 9K are described. Also in the contact development method in which the contact is made, the same effect as described above can be obtained. In the present embodiment, the “toner running out” of the most frequently encountered print stop condition has been described in detail. The print stop condition is a life due to a decrease in the film thickness of the photosensitive drum, deterioration due to rotation of the developer carrier, Needless to say, the number of printed sheets may indicate the usage status of the process cartridge. Further, the new sequence is not limited to the lubricant application process by rotating the photosensitive drum, but can be sufficiently applied to cases where it is necessary to add another rotational drive.

<Embodiment 2>
The operation of the image forming apparatus according to the second embodiment will be described with reference to FIG.

  The image forming apparatus according to the present embodiment will be described in the case where the fourth process cartridge 8K is replaced with “out of toner” in the image forming apparatus described in the first embodiment. In addition, the figure, symbol, etc. of Embodiment 1 are used.

  When a request for full-color image formation is issued from the host, and “out of toner” of the process cartridge 8K is detected during the above-described full-color image formation operation, the rear end of the recording paper 1 is transferred to the third process cartridge 8Y by the transfer conveyance belt 7. The clutch 41 is immediately controlled by the control unit 43 provided in the image forming apparatus as soon as it passes through each transfer unit T3 and receives the action of the transfer unit 13K only in the transfer unit T4 of the fourth process cartridge 8K. As a result, the transfer / conveying belt 7 is moved from the full-color position (position where it contacts the photosensitive drums 9M to 9K) to the mono-color position (position where it is separated from the photosensitive drums 9M to 9Y).

  At the same time as the photosensitive drums 9M to 9Y and the transfer / conveying belt 7 are separated from each other, drive control is performed by the control unit 37 serving as a control unit, and the rotational drive of the process cartridges 8M to 8C is stopped. By quickly transitioning to a state in which monocolor image formation is possible in this way, the process cartridge that is not used for image formation is consumed in the case where the photosensitive drum and others are stopped while being rotationally driven at the full color position. Can be suppressed. In this state, the process proceeds to the post-rotation operation of the black process cartridge, and the image forming apparatus is stopped.

  Next, when the user replaces the process cartridge 8K, the transfer / conveying belt 7 maintains a monochromatic position that is a position away from the photosensitive drums 9M to 9Y. The image forming apparatus receives information indicating that “the process cartridge is new” from the memory 27K which is a storage unit mounted on the process cartridge 8K, and zinc stearate which is a lubricant on the surface of the photosensitive drum 9K which is a new sequence. In order to actively apply 26K, the photosensitive drum 9K is driven to rotate and the transfer / conveying belt 7 is driven for a predetermined time. At this time, the controller 37 drives only the photosensitive drum 9X and does not drive other color cartridges.

  In this way, when the process cartridge 8K is exchanged at the monocolor position (position separated from the photosensitive drums 9M to 9Y), the photosensitive drums 9M to 9Y that have stopped from the transfer conveyance belt are damaged by the difference in the peripheral speed between them. It is possible to solve the above-mentioned problem that the photosensitive drum is consumed due to unnecessary rotation of the photosensitive drum in the process cartridge other than the replacement in order to prevent a defect from being generated.

  It goes without saying that with the above configuration, even in an image forming apparatus using an intermediate transfer belt, consumption of a process cartridge that is not used can be suppressed. In the present embodiment, the developing sleeves 12M1 to 12K1 and the photosensitive drums 9M to 9K have been described using a non-contact developing method. However, the developing sleeves 12M1 to 12K1 and the photosensitive drums 9M to 9K are described. Also in the contact development method in which the contact is made, the same effect as described above can be obtained.

  In the present embodiment, the “toner running out” of the most frequently encountered print stop condition has been described in detail. The print stop condition is a life due to a decrease in the film thickness of the photosensitive drum, deterioration due to rotation of the developer carrier, Needless to say, the number of printed sheets may indicate the usage status of the process cartridge. Further, the new sequence is not limited to the lubricant application process by rotating the photosensitive drum, but can be sufficiently applied to cases where it is necessary to add another rotational drive.

1 is a configuration diagram of an image forming apparatus according to Embodiment 1 of the present invention. It is a figure which shows the lubricant application mechanism of the image forming apparatus which concerns on this invention. FIG. 7 is a diagram illustrating a state where only a fourth process cartridge is driven in the image forming apparatus of FIG. 1. FIG. 2 is a process cartridge drive control block diagram of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram of a transfer conveyance belt drive control of the image forming apparatus according to the first embodiment of the present invention. 3 is a flowchart illustrating an operation of the image forming apparatus according to the first embodiment of the present invention. 6 is a flowchart illustrating an operation of the image forming apparatus according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording material 5 Belt drive roller 7 Transfer conveyance belt (transfer material conveyance means)
8M, 8C, 8Y, 8K Process cartridge 9M, 9C, 9Y, 9K Photosensitive drum (image carrier)
10M, 10C, 10Y, 10K Charger 11M, 11C, 11Y, 11K Exposure unit 12M, 12C, 12Y, 12K Developer (developing means)
13M, 13C, 13Y, 13K Transfer device (transfer means)
14M, 14C, 14Y, 14K Cleaning blade 15 Fixing device

Claims (7)

A plurality of process cartridges that are integrated with a photosensitive drum that is an electrostatic latent image carrier and a developing unit that develops an electrostatic latent image and that can be attached to and detached from the image forming apparatus, around the belt-like transfer unit In the image forming apparatus arranged in
There are a color mode for forming a multi-color image and a mono-color mode for forming a black image. In the mono-color mode, the process cartridges other than black and the belt-like transfer unit are separated from each other. An image forming apparatus, wherein when the stop condition is satisfied, the stopped process cartridge is replaced with a process cartridge other than black and the belt-shaped transfer unit being separated from each other.   The image forming apparatus according to claim 1, wherein the belt-shaped transfer unit is an intermediate transfer belt or a transfer conveyance belt.   3. The image forming apparatus according to claim 1, wherein the stop conditions of the process cartridge are conditions relating to a life of the photosensitive drum, no developer, a rotation time of the developer carrier, and a number of printed sheets. A plurality of process cartridges that are integrated with a photosensitive drum that is an electrostatic latent image carrier and a developing unit that develops an electrostatic latent image and that can be attached to and detached from the image forming apparatus, around the belt-like transfer unit In the image forming apparatus arranged in
There are a color mode for forming a multicolor image and a monocolor mode for forming a black image. In the monocolor mode, a process cartridge other than black is separated from the belt-shaped transfer unit, When the stop condition of the process cartridge is satisfied, the process cartridge that is not black and the belt-shaped transfer unit are separated from each other, the stopped process cartridge is replaced, and the belt-shaped transfer unit and the rotation of the process cartridge other than the replaced cartridge are performed. An image forming apparatus that performs rotation driving at the time of initial installation of a replaced process cartridge in a state where driving is stopped. A plurality of process cartridges that are integrated with a photosensitive drum that is an electrostatic latent image carrier and a developing unit that develops an electrostatic latent image and that can be attached to and detached from the image forming apparatus, around the belt-like transfer unit In the image forming apparatus arranged in
There are a color mode for forming a multicolor image and a monocolor mode for forming a black image. In the monocolor mode, the process cartridge other than black is separated from the belt-shaped transfer means, and the black process When the stop condition for the cartridge is satisfied, the black process cartridge is replaced with the non-black process cartridge and the belt-shaped transfer unit being separated from each other. An image forming apparatus that performs rotational driving at the time of initial installation of a process cartridge.   6. The image forming apparatus according to claim 5, wherein the belt-shaped transfer means is driven to rotate simultaneously with the rotation driving at the time of initial installation of the black process cartridge.   7. The image forming apparatus according to claim 5, wherein the stop condition of the process cartridge is a condition relating to a life of the photosensitive drum, no developer, a rotation time of the developer carrier, and a number of printed sheets.

Images