JP7139785B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, as an image forming apparatus, a plurality of toner images of different colors formed on a plurality of image holding means are primarily transferred onto an intermediate transfer member in a superimposed state, and then collectively transferred from the intermediate transfer member onto a recording sheet. There is a device configured to form a full-color image or the like by performing secondary transfer with the toner. Techniques related to such image forming apparatuses have already been proposed, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100000.

Patent Document 1 discloses a current path forming member that forms a current path for transferring a toner image between an image carrier, a belt-shaped member, and a facing component connected to a power source and opposed via the belt-shaped member. and discrimination means for discriminating the type of the current path forming member based on the result of detection of the current or voltage applied to the current path forming member, wherein the power source is the current path discriminated by the discrimination means. It is configured to operate according to the type of forming member.

JP 2014-115355 A

An object of the present invention is to discriminate erroneous use of the intermediate transfer means as compared with the case where no discriminating means for discriminating between the color intermediate transfer means and the monochromatic intermediate transfer means is provided.

The invention described in claim 1 is configured to be attachable/detachable to both a first apparatus main body having a plurality of image holding means and a second apparatus main body having a single image holding means, and an intermediate transfer means having a plurality of or a single transfer means for respectively transferring an image from the image holding means of the main body;
determining means for determining whether or not the intermediate transfer means is suitable by detecting current or voltage applied to the transfer means;
with
The image forming apparatus is provided with a notification means for notifying a user of the determination result when the determination means determines that the intermediate transfer means having the single transfer means is attached to the first apparatus main body .

The image forming apparatus according to claim 1, further comprising switching means provided in the first apparatus main body for switching the transfer operations of the plurality of transfer means based on the determination result of the determination means. It is a device.

In the invention recited in claim 3 , when the determination means determines that the intermediate transfer means having the single transfer means is attached to the first apparatus main body, the switching means switches between the plurality of transfer means. 3. The image forming apparatus according to claim 1 , wherein only the transfer operation corresponding to one of the transfer means is switched to be executable.

In the invention described in claim 4 , the intermediate transfer means is provided in the second apparatus main body and has any of the plurality of transfer means or the single transfer means by detecting current or voltage applied to the transfer means. a determination means for determining whether there is
The image forming apparatus according to claim 1, comprising:

In the invention described in claim 5 , when the determination means determines that the intermediate transfer means having the plurality of transfer means is attached to the second apparatus main body, the notification means notifies the user of the determination result. 5. The image forming apparatus according to claim 4 .

In the invention described in claim 6 , the determination means supplies a transfer current from a plurality of or a single power supply to the plurality or a single image holding means and the transfer means via a current path that supplies a transfer current, 6. The image forming apparatus according to any one of claims 1 to 5 , wherein current or voltage applied to said transfer means is detected.

According to the first aspect of the present invention, the erroneous use of the intermediate transfer means can be prevented compared to the case where no discriminating means for discriminating between the intermediate transfer means for color and the intermediate transfer means for monochrome is provided. can be discriminated.
Further, according to the first aspect of the invention, when the determination means determines that the intermediate transfer means having the single transfer means is attached to the first apparatus body, the result of the determination is sent to the user. The user can easily judge whether the intermediate transfer means is appropriate or not, compared to the case where no notification means is provided.

According to the invention described in claim 2, compared to the case where the switching means provided in the first apparatus main body and switching the transfer operation by the plurality of transfer means based on the determination result of the determination means is not provided. Even when the determination result of the intermediate transfer means by the determination means is negative, the monochrome image forming operation can be executed.

According to the invention recited in claim 3 , when the determination means determines that the intermediate transfer means having the single transfer means is attached to the first apparatus main body, the switching means switches between the plurality of transfer means. The monochrome image forming operation can be reliably executed as compared with the case where only the transfer operation corresponding to one of the transfer means is not switched to be executable.

According to the invention described in claim 4 , the intermediate transfer device provided in the second apparatus main body and having either the plurality of transfer means or the single transfer means is detected by detecting the current or voltage applied to the transfer means. As compared with the case where no discriminating means for discriminating whether the intermediate transfer means is appropriate, the second apparatus main body can also discriminate whether or not the intermediate transfer means is appropriate.

According to the fifth aspect of the invention, when the determination means determines that the intermediate transfer means having the plurality of transfer means is attached to the second apparatus main body, the user is notified of the result of the determination. The user can easily judge the suitability of the intermediate transfer means as compared with the case where no means is provided.

According to the sixth aspect of the present invention, the discriminating means supplies a transfer current from a plurality of or a single power supply to the plurality of or a single image holding means and the transfer means via a current path. Therefore, as compared with the case where the current or voltage applied to the transfer means is not detected, addition of a new configuration is unnecessary.

1 is a schematic configuration diagram showing a color image forming apparatus as an image forming apparatus according to Embodiment 1 of the present invention; FIG. FIG. 2 is a schematic configuration diagram showing a monochrome image forming apparatus as another image forming apparatus according to Embodiment 1 of the present invention; (a) and (b) are configuration diagrams showing intermediate transfer units for color and monochrome, respectively. 3 is an external perspective view showing an intermediate transfer unit for color and monochrome; FIG. 3 is a configuration diagram showing a contacting/separating means of an intermediate transfer unit for color; FIG. 3 is a configuration diagram showing a high-voltage power supply of an intermediate transfer unit for color; FIG. 1 is a block diagram showing a control device of a color image forming apparatus as an image forming apparatus according to Embodiment 1 of the present invention; FIG. 2 is a configuration diagram showing a high-voltage power supply of an intermediate transfer unit for monochrome; FIG. 2 is a configuration diagram showing a state in which an intermediate transfer unit for color is attached to a monochrome image forming apparatus; FIG. 2 is a configuration diagram showing a state in which a monochrome intermediate transfer unit is attached to a color image forming apparatus; FIG. 1A and 1B are equivalent circuit diagrams showing a color intermediate transfer unit and a monochrome intermediate transfer unit, respectively. 2 is an equivalent circuit diagram showing a state in which a monochrome intermediate transfer unit is attached to a color image forming apparatus; FIG. 4 is a flow chart showing the control operation of the color image forming apparatus as the image forming apparatus according to Embodiment 1 of the present invention; FIG. 2 is an equivalent circuit diagram showing essential parts of a monochrome image forming apparatus as an image forming apparatus according to Embodiment 2 of the present invention; 8 is a block diagram showing a control circuit of a monochrome image forming apparatus as an image forming apparatus according to Embodiment 2 of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 shows an overall outline of a color image forming apparatus as an example of an image forming apparatus according to the first embodiment, and FIG. 2 shows a monochrome image forming apparatus as an example of the image forming apparatus according to the first embodiment. It shows the outline of the whole. In the drawing, arrow X indicates the width direction along the horizontal direction, Y indicates the depth direction along the horizontal direction, and Z indicates the vertical direction.

<Overall Configuration of Color Image Forming Apparatus>
The color image forming apparatus 1 is configured as, for example, a color printer. As shown in FIG. 1, this color image forming apparatus 1 includes an image forming device 10 as an example of a plurality of image forming means for forming a toner image developed with toner constituting a developer, and each image forming device. an intermediate transfer device 20 as an example of intermediate transfer means that conveys the toner images formed in step 10 to a secondary transfer position T2 where they are respectively held and finally secondary-transferred onto a recording paper 5 as an example of a recording medium; A paper feeding device 50 that accommodates and conveys the required recording paper 5 to be supplied to the secondary transfer position T2 of the intermediate transfer device 20, and the toner image on the recording paper 5 secondarily transferred by the intermediate transfer device 20 is fixed. A fixing device 40 or the like is provided for fixing the image. Reference numeral 1a denotes a first device main body formed of a support structure member, an exterior cover, and the like.

The image forming device 10 includes four image forming devices 10Y, 10M, 10C, and 10BK that respectively form four-color toner images of yellow (Y), magenta (M), cyan (C), and black (BK). It is configured. These four image forming devices 10 (Y, M, C, BK) are arranged in a row while being inclined with respect to the horizontal direction X in the internal space of the first device body 1a.

As shown in FIG. 1, each imaging device 10 (Y, M, C, BK) has a photosensitive drum 11 as an example of a rotating image holding means. , the following devices are mainly arranged. The main devices are a charging device 12 that charges the peripheral surface (image holding surface) of the photosensitive drum 11 on which an image can be formed (image holding surface) to a required potential, and image information ( an exposure device 13 as an example of an electrostatic latent image forming means for forming an electrostatic latent image (for each color) having a potential difference by irradiating light based on the signal), and forming the electrostatic latent image in the corresponding color (Y , M, C, and BK) as an example of developing means to form a toner image, and a primary transfer means as an example of a transfer means for transferring each toner image to an intermediate transfer device 20. They are a transfer device 15 and a drum cleaning device 16 as an example of cleaning means for cleaning the image holding surface of the photosensitive drum 11 after the primary transfer by removing toner and other adhering substances remaining on the image holding surface of the photoreceptor drum 11 .

The photoreceptor drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar base material to be grounded. The photoreceptor drum 11 is supported so as to rotate in the direction indicated by the arrow A when a driving force is transmitted from a driving device (not shown).

The charging device 12 is composed of a contact-type charging roll 120 arranged in contact with the photosensitive drum 11 . A charging voltage is supplied to the charging device 12 . As the charging voltage, when the developing device 14 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied. A cleaning roll 121 that cleans the surface of the charging roll 120 is arranged in contact with the back side of the charging roll 120 .

The exposure device 13 irradiates the photosensitive drum 11 with light according to image information from LEDs (Light Emitting Diodes) as a plurality of light emitting elements arranged along the axial direction of the photosensitive drum 11 to form an electrostatic latent image. It consists of an LED print head or the like that forms a Information (signal) of an image input to the color image forming apparatus 1 by any means is transmitted to the exposure device 13 at the time of latent image formation. Note that the exposure device 13 irradiates the peripheral surface of the photosensitive drum 11 after being charged with a laser beam configured according to information of an image input to the color image forming apparatus 1 to generate an electrostatic charge. A material that forms a latent image may also be used.

As shown in FIG. 1, each of the developing devices 14 (Y, M, C, and K) holds and exposes the developer inside a housing 140 having an opening and an accommodating chamber for the developer. A developing roll 141 that conveys the developer to a developing area facing the body drum 11 , agitating and conveying members 142 and 143 such as screw augers that convey the developer so that it passes through the developing roll 141 while agitating the developer, and a developer held by the developing roll 141 . It is constructed by arranging a layer thickness regulating member 144 for regulating the amount (layer thickness) of the agent. A developing voltage is supplied to the developing device 14 between the developing roller 141 and the photosensitive drum 11 from a power supply device (not shown). Further, the developing roll 141 and the agitating/conveying members 142 and 143 are rotated in desired directions by transmission of a driving force from a driving device (not shown). Furthermore, two-component developers containing non-magnetic toner and magnetic carrier are used as the four-color developers (Y, M, C, K).

Yellow (Y), magenta (M), cyan (C), and black (BK) toners arranged above the intermediate transfer device 20 are provided in the respective developing devices 14 (Y, M, C, K). The cartridges 145 (Y, M, C, and K) are configured to be replenished with toner of corresponding colors through a toner replenishing device (not shown).

The primary transfer device 15 is a contact-type transfer device having a primary transfer roll that rotates in contact with the circumferential surface of the photosensitive drum 11 via the intermediate transfer belt 21 at the primary transfer position T1 and is supplied with a voltage for primary transfer. is. As the primary transfer device 15, there is used one in which an elastic layer made of foamed rubber containing epichlorohydrin rubber and nitrile rubber is coated on the outer periphery of a metal core made of stainless steel or the like. The primary transfer device 15 is adjusted to have a required resistance value by adding a conductive agent to the elastic layer. As the voltage for primary transfer, a DC voltage or current having a polarity opposite to the charging polarity of the toner is supplied from a high-voltage power supply as will be described later.

The drum cleaning device 16 includes a cleaning blade 161 disposed inside a container-shaped main body 160 for cleaning by removing deposits such as residual toner, and for recovering deposits such as toner removed by the cleaning blade 161 (not shown). It consists of a delivery member 162, such as a screw auger, which is conveyed for delivery to a collection system.

The intermediate transfer device 20 is arranged to exist above each image forming device 10 (Y, M, C, BK). The intermediate transfer device 20 includes an intermediate transfer belt 21 that circulates in the direction indicated by an arrow B while passing a primary transfer position T1 between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll); A plurality of belt support rolls 22 to 25 that hold the belt 21 in a desired state from the inner circumference and support it so as to be circulating, and an outer peripheral surface (image holding surface) of the intermediate transfer belt 21 supported by the belt support roll 25. ) side of the intermediate transfer belt 21 to secondarily transfer the toner image on the intermediate transfer belt 21 onto the recording paper 5, It is mainly composed of a belt cleaning device 26 for cleaning by removing adhering matter such as toner and paper dust.

As the intermediate transfer belt 21, an endless belt made of a synthetic resin such as polyimide resin or polyamide resin in which a resistance adjusting agent such as carbon black is dispersed is used. Further, the belt support roll 22 is configured as a drive roll, the belt support roll 23 is configured as a leveling roll that holds the running position of the intermediate transfer belt 21, and the belt support roll 24 is configured as a tensioning roll. 25 is configured as a backup roll for secondary transfer.

As shown in FIG. 3A, the intermediate transfer device 20 of the color image forming apparatus 1 includes an intermediate transfer belt 21, a plurality of belt support rolls 22 to 25, and a primary transfer device 15 (Y, M, C, BK) and the belt cleaning device 26 are integrated as an intermediate transfer unit 200C for color. The intermediate transfer unit 200C can be attached to and detached from the first apparatus body 1a by opening and closing a cover (not shown).

As shown in FIG. 4, the intermediate transfer unit 200C includes front side and rear side frames 201 and 202 arranged at both ends along the width direction crossing the moving direction of the intermediate transfer belt 21. . Both side frames 201 and 202 rotatably support belt support rolls 22 to 25 and a primary transfer device 15 (Y, M, C, BK). In the drawing, reference numerals 203 and 204 denote gripping portions for gripping the intermediate transfer unit 200C.

As shown in FIG. 1, the secondary transfer device 30 rotates at a secondary transfer position T2, which is the outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 25 in the intermediate transfer device 20. A roll 31 is provided. The secondary transfer roll 31 or the belt support roll 25 of the intermediate transfer device 20 is supplied with a DC voltage having the same or opposite polarity as the charging polarity of the toner as a secondary transfer voltage.

The fixing device 40 includes a belt-shaped or roll-shaped heating rotator 41 heated by a heating means such as electromagnetic induction heating or a heat source so that the surface temperature is maintained at a predetermined temperature, and the heating rotator 41 . It is constructed by arranging a roll-type or belt-type pressurizing rotator 42 or the like that contacts and rotates with a required pressure. In this fixing device 40, the contact portion where the heating rotator 41 and the pressurizing rotator 42 are in contact serves as a fixing processing portion N for performing required fixing processing (heating and pressing).

The sheet feeding device 50 is arranged to exist below the image forming devices 10 (Y, M, C, K). This paper feeding device 50 includes a single (or a plurality of) paper containers 52 that contain recording paper 5 of a desired size and type while being stacked on a stacking plate 51 , and the recording paper 5 is loaded from the paper container 52 . It is mainly composed of a sending device 53 for sending out one sheet at a time. The paper container 52 is attached so as to be able to be pulled out, for example, on the front side (the side facing the user during operation) of the first apparatus main body 1a.

As the recording paper 5, for example, thin paper such as plain paper or tracing paper used in electrophotographic copying machines, printers, etc., or an OHP sheet made of a transparent film-like medium made of synthetic resin (such as PET). etc. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper 5 is as smooth as possible. A so-called thick paper having a relatively large basis weight can also be suitably used.

Between the paper feeding device 50 and the secondary transfer device 30, there are a single (or a plurality of) paper transport roll pairs 54 for transporting the recording paper 5 fed from the paper feeding device 50 to the secondary transfer position T2, and a transport guide material. A paper feed transport path 57 composed of 55 and 56 is provided. A pair of paper transport rolls 54 arranged at a position immediately before the secondary transfer position T2 in the paper feed transport path 57 is configured as rolls (registration rolls) for adjusting the transport timing of the recording paper 5, for example.

Between the secondary transfer device 30 and the fixing device 40, there is provided a paper transport path 59 including a transport guide member 58 for transporting the recording paper 5 fed from the secondary transfer device 30 to the fixing device 40. It is

On the downstream side of the fixing device 40, a pair of paper transport rolls 61 for discharging the recording paper 5 on which the toner image has been fixed by the fixing device 40 to a paper discharge section 60 arranged in the upper part of the first apparatus main body 1a; A discharge transport path 65 having a paper discharge roll pair 62, transport guide members 63 and 64, and the like is provided.

In FIG. 1, reference numeral 100 designates a control device as an example of control means for overall control of the operation of the color image forming apparatus 1. As shown in FIG.

The color image forming apparatus 1 has a full-color mode and a monochrome mode as image modes. In the full-color mode, as shown in FIG. 1, primary transfer devices in respective image forming devices 10 (Y, M, C, BK) for yellow (Y), magenta (M), cyan (C), and black (BK) 15 is in contact with the surface of the photosensitive drum 11 via the intermediate transfer belt 21 . On the other hand, in the monochrome mode, among the yellow (Y), magenta (M), cyan (C), and black (BK) image forming devices 10 (Y, M, C, BK), black (BK) image forming is performed. Only the primary transfer device 15 of the device 10BK contacts the surface of the photosensitive drum 11 via the intermediate transfer belt 21, and the other yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y). , M and C) have moved to the retracted position away from the intermediate transfer belt 21 .

As shown in FIG. 5, the color intermediate transfer unit 200C transfers yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y, M, C) to the photosensitive drums 11 (Y). , M, C) are provided with a contacting/separating means 150 for contacting and separating from the surface of the intermediate transfer belt 21 . The contact/separation means 150 mainly includes a swing arm 151 that rotatably supports the yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y, M, and C), and a swing arm 151 that supports the primary transfer devices 15 (Y, M, and C). and a slide member 152 for rocking at a required timing.

The swing arm 151 is attached to the intermediate transfer unit 200C so as to swing about a fulcrum 153. As shown in FIG. Also, the swing arm 151 is biased clockwise by a coil spring 154 . The slide member 152 is formed in the shape of an elongated rod, and is attached to the intermediate transfer unit 200C so as to be movable along the direction indicated by the arrow C. As shown in FIG. Further, the drive portion 152a of the slide member 152 is provided in contact with an eccentric cam 155 attached to the intermediate transfer unit 200C. The eccentric cam 155 is rotationally driven at a required timing by transmitting a driving force from the first device main body 1a side.

The slide member 152 has a driving portion 152a and a convex portion 152b projecting downward at desired positions along the longitudinal direction. A drive portion 152 a of the slide member 152 is in contact with an eccentric cam 155 . The convex portion 152b of the slide member 152 is in contact with the operating portion 151a of the swing arm 151 biased by the coil spring 154. As shown in FIG.

In the color intermediate transfer unit 200C, as shown in FIG. 5A, in the color mode, when the eccentric cam 155 is rotated to the retracted position, the driving portion 152a of the slide member 152 in contact with the eccentric cam 155 is moved. The urging force of the coil spring 154 moves rightward in the figure. As a result, the swing arm 151 rotates clockwise in FIG. C) contacts the surfaces of the photosensitive drums 11 (Y, M, C) via the intermediate transfer belt 21 .

On the other hand, in the color intermediate transfer unit 200C, when the eccentric cam 155 is rotated to the operating position in the monochrome mode, as shown in FIG. 152a resists the biasing force of the coil spring 154 and moves leftward in the figure. Then, the swing arm 151 rotates counterclockwise in the drawing against the biasing force of the coil spring 154 to rotate the yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y). , M, C) moves to the retracted position away from the surface of the photosensitive drum 11 (Y, M, C). At the same time, the belt support roll 23 on which the intermediate transfer belt 21 is stretched is displaced to the retracted position with the movement of the slide member 152, and the intermediate transfer belt 21 is yellow (Y), magenta (M), and cyan (M). C) moves to a retracted position away from the surface of the photosensitive drum 11 (Y, M, C).

Normally, in the color intermediate transfer unit 200C, yellow (Y), magenta (M) and cyan (C) primary transfer devices 15 (Y, M, C) are exposed to light as shown in FIG. 5B. It is in a state of being moved to a retracted position away from the surface of the body drums 11 (Y, M, C).

As shown in FIG. 6, the intermediate transfer unit 200C is attached to the first apparatus main body 1a of the color image forming apparatus 1, so that the primary transfer device 15 (Y, M, C, BK) is charged with the polarity of the toner. A primary transfer bias voltage of opposite polarity is applied by the high voltage power supply 156 (Y, M, C, BK). A constant-current power supply, for example, is used as the high-voltage power supply 156 (Y, M, C, BK). However, the high voltage power supply is not limited to this, and a constant voltage power supply may be used.

FIG. 7 is a block diagram showing the control device of the color image forming apparatus 1 according to the first embodiment.

The control device 100 includes a control section 101 as an example of determination means and switching means, a storage section 102 and an operation section 103 .

The control unit 101 executes programs stored in the storage unit 102 and controls the image forming operation of the color image forming apparatus 1 . The control unit 101 controls the storage unit 102 and the operation unit 103, and communicates with a user's personal computer (not shown) or the like via a communication unit (not shown).

The operation unit 103 includes an input unit 103a through which the user inputs the type of recording paper 5, the number of prints, an image forming mode such as a full-color mode or a monochrome mode, and an input unit 103a for instructing the start of an image forming operation by pressing a start button. A display unit 103b is provided as an example of notification means for displaying the image forming conditions input at 103a and a message to the user.

<Basic Operation of Color Image Forming Apparatus>
A basic image forming operation of the color image forming apparatus 1 will be described below.

Here, when the four image forming devices 10 (Y, M, C, BK) are used to form a full-color image formed by combining toner images of four colors (Y, M, C, BK), image forming operation will be described. It should be noted that when an image is formed by combining single-color or multiple-color toner images using one or more of the four image forming devices 10 (Y, M, C, BK), The image forming operation is basically the same.

Upon receiving command information requesting an image forming operation (printing), the color image forming apparatus 1 is controlled by the control device 100 to operate the four image forming devices 10 (Y, M, C, BK), the intermediate transfer device 20, The secondary transfer device 30, fixing device 40, etc. are started.

In each imaging device 10 (Y, M, C, BK), as shown in FIG. 1, each photosensitive drum 11 first rotates in the direction indicated by arrow A, and each charging device 12 rotates each photosensitive drum. The surface of the body drum 11 is charged to a desired polarity (negative polarity in the first embodiment) and potential. Subsequently, the exposing device 13 converts the information of the image input to the color image forming device 1 into each color component (Y, M, C, BK) for the surface of the photosensitive drum 11 after charging. Light emitted based on image signals is applied to form an electrostatic latent image of each color component, which is composed of a required potential difference, on its surface.

Subsequently, each developing device 14 (Y, M, C, BK) charges the electrostatic latent image of each color component formed on the photosensitive drum 11 with a corresponding color charged to a required polarity (negative polarity). (Y, M, C, BK) toners are supplied and electrostatically adhered to each other for development. By this development, the electrostatic latent image of each color component formed on each photosensitive drum 11 is visualized as a four-color (Y, M, C, BK) toner image developed with the corresponding color toner. become.

Subsequently, when the toner images of the respective colors formed on the photosensitive drums 11 of the image forming devices 10 (Y, M, C, BK) are conveyed to the primary transfer position T1, the primary transfer device 15 transfers the toner images of the respective colors. The toner images are primarily transferred onto the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20 so as to be superimposed in order.

In each image forming device 10 (Y, M, C, BK) after primary transfer, the drum cleaning device 16 cleans the surface of the photosensitive drum 11 by scraping off the adhering matter. As a result, each image forming device 10 (Y, M, C, BK) is ready for the next image forming operation.

Subsequently, in the intermediate transfer device 20, the primarily transferred toner image is held by the rotation of the intermediate transfer belt 21 and conveyed to the secondary transfer position T2. On the other hand, the paper feeding device 50 feeds out the required recording paper 5 to the paper feeding path 57 in accordance with the image forming operation. In the paper feed path 57, a pair of paper transport rolls 54 serving as resist rolls feeds and supplies the recording paper 5 to the secondary transfer position T2 in accordance with the transfer timing.

At the secondary transfer position T2, the secondary transfer roll 31 collectively secondary-transfers the toner images on the intermediate transfer belt 21 onto the recording paper 5 . In the intermediate transfer device 20 after the secondary transfer is completed, the belt cleaning device 26 cleans the surface of the intermediate transfer belt 21 after the secondary transfer by removing deposits such as toner remaining on the surface of the intermediate transfer belt 21 .

Subsequently, the recording paper 5 on which the toner image has been secondarily transferred is separated from the intermediate transfer belt 21 and the secondary transfer device 30 and then transported along the paper transport path 59 to the fixing device 40 . In the fixing device 40, the recording paper 5 after the secondary transfer is introduced into the fixing processing section N between the heating rotator 41 composed of a rotating heating roll and the pressure rotator 42 composed of a pressure belt. Then, the unfixed toner image is fixed on the recording paper 5 by performing necessary fixing processing (heating and pressure). After fixing, the recording paper 5 is discharged to the paper discharge section 60 provided in the upper part of the first apparatus main body 1a by the paper discharge roll pair 62 via the discharge transport path 65 .

By the above operation, a full-color image formed by combining toner images made up of four color toners T (Y, M, C, BK) is output.

On the other hand, when the color image forming apparatus 1 is in monochrome mode, as shown in FIG. moves to the retracted position away from the surface of the photoreceptor drum 11 (Y, M, C), and only the black (BK) primary transfer device 15BK is in contact with the surface of the photoreceptor drum 11BK.

Then, in the color image forming apparatus 1 , the black (BK) image forming device 10BK executes an image forming operation to form a monochrome image on the recording paper 5 .

<Overall Configuration of Monochrome Image Forming Apparatus>
The monochrome image forming apparatus 2 is configured as, for example, a monochrome printer. The monochrome image forming apparatus 2 is designed in common with the color image forming apparatus 1 .

That is, as shown in FIG. 2, the monochrome image forming apparatus 2 is mainly composed of a black (BK) image forming apparatus having a black (BK) photosensitive drum 11 as a single image holding means. It is composed only of the device 10BK, and does not have the image forming devices 10 (Y, M, C) for yellow (Y), magenta (M), and cyan (C). In relation to this, the monochrome image forming apparatus 2 is different only in that it includes only a black (BK) primary transfer device 15BK as an example of a transfer means and a black (BK) toner cartridge 145BK. Other components such as the intermediate transfer device 20 , the fixing device 40 , the paper feeding device 50 and the paper transport path are configured in the same manner as in the color image forming apparatus 1 . In FIG. 2, reference numeral 2a denotes a second device main body formed of a support structural member, an exterior cover, and the like.

More specifically, the color image forming apparatus 1 includes four image forming devices 10 (Y, M, C, BK) for yellow (Y), magenta (M), cyan (C), and black (BK). On the other hand, the second device main body 2a of the monochrome image forming device 2 is configured to include only the black (BK) image forming device 10BK.

In the color image forming apparatus 1, the intermediate transfer device 20 includes four primary transfer devices 15 (Y, M, C, BK) corresponding to the four image forming devices 10 (Y, M, C, BK). 3B, the monochrome image forming apparatus 2 has only one primary transfer device 15BK corresponding to the image forming device 10BK whose intermediate transfer device 20 is black (BK). .

Further, the color image forming apparatus 1 is provided with four toner cartridges 145 (Y, M, C, BK) of yellow (Y), magenta (M), cyan (C) and black (BK). The device 2 includes only a black (BK) toner cartridge 145BK.

The intermediate transfer device 20 is integrally configured as an intermediate transfer unit 200M for monochrome. The intermediate transfer unit 200M is detachable from the second apparatus body 2a of the monochrome image forming apparatus 2. As shown in FIG.

As described above, the monochrome intermediate transfer unit 200M includes only the black (BK) primary transfer device 15BK, and the yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y, M). , C). Further, the monochrome intermediate transfer unit 200M has contact/separation means 150 for moving the yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y, M, and C) to the retreat position. Not provided.

However, the yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y, M, C) and the contact/separation means 150 are members arranged inside the color intermediate transfer unit 200C. Therefore, as shown in FIG. 4, the monochrome intermediate transfer unit 200M is configured in an external appearance substantially similar to the color intermediate transfer unit 200C.

As shown in FIG. 8, the monochrome image forming apparatus 2 includes only a high-voltage power supply 156BK that supplies a required primary transfer bias voltage to the black (BK) primary transfer device 15BK.

In this way, the monochrome image forming apparatus 2 has a common design with the color image forming apparatus 1, and is basically capable of forming a color image, except for having only a configuration capable of forming a black (BK) image. The configuration is shared with the forming apparatus 1 .

Correspondingly, the monochrome intermediate transfer unit 200M has a common configuration with the color intermediate transfer unit 200C, as shown in FIGS. 3(a) and 3(b). As a result, the intermediate transfer unit 200C for color and the intermediate transfer unit 200M for monochrome can be attached to and detached from both the first apparatus main body 1a of the color image forming apparatus 1 and the second apparatus main body 2a of the monochrome image forming apparatus 2. It is configured.

The intermediate transfer units 200C and 200M for color and monochrome are attached to the first apparatus main body 1a of the color image forming apparatus 1 or the second apparatus main body 2a of the monochrome image forming apparatus 2, whereby the first apparatus main body 1a or The driving force is transmitted from the second apparatus body 2a and is configured to be energized to the primary transfer devices 15 (Y, M, C, BK).

<Basic Operation of Monochrome Image Forming Apparatus>
A basic image forming operation of the monochrome image forming apparatus 2 will be described below.

When the monochrome image forming apparatus 2 receives command information requesting an image forming operation (printing), the controller 100 controls the image forming apparatus 10BK, the intermediate transfer device 20, the secondary transfer device 30, and the fixing device 40. etc. is started.

In the monochrome image forming apparatus 2, similarly to the monochrome mode of the color image forming apparatus 1, an image forming operation is performed in the image forming apparatus 10BK for black (BK).

By the above operation, a monochrome image formed by a toner image made of black toner T(K) is output onto the recording paper 5 .

<Configuration of Characteristic Portions of Image Forming Apparatus>
As described above, the image forming apparatus according to the first embodiment has a common design for the color image forming apparatus 1 and the monochrome image forming apparatus 2. , etc. are different, and are basically configured in the same manner.

Similarly, the intermediate transfer units 200C and 200M for color and monochrome also differ in the number of primary transfer devices 15 and the presence/absence of contact/separation means, etc., as shown in FIGS. are similarly constructed. The intermediate transfer unit 200C for color and the intermediate transfer unit 200M for monochrome have similar appearances, as shown in FIG.

Therefore, it is difficult to distinguish between the color intermediate transfer unit 200C and the monochrome intermediate transfer unit 200M in terms of appearance. There is a possibility that the intermediate transfer unit 200C and the monochrome intermediate transfer unit 200M are installed in the first apparatus main body 1a of the color image forming apparatus 1 or the second apparatus main body 2a of the monochrome image forming apparatus 2 by mistake.

In this case, as shown in FIG. 9, even if the color intermediate transfer unit 200C is erroneously installed in the monochrome image forming apparatus 2, the yellow (Y), magenta (M), and cyan (C) image forming apparatuses 10 (Y, M, C) does not exist and does not operate, there is no problem in terms of function as the monochrome image forming apparatus 2 .

That is, the monochrome image forming apparatus 2 includes only the image forming device 10BK and the primary transfer device 15BK for black, and the high voltage power supply 156BK corresponding to the primary transfer device 15BK for the image forming device 10BK for black. Since there is no high-voltage power supply 156 (Y, M, C) corresponding to the magenta (M) and cyan (C) primary transfer devices 15 (Y, M, C), there is no operational problem.

On the other hand, as shown in FIG. 10, when the monochrome intermediate transfer unit 200M is erroneously installed in the first apparatus body 1a of the color image forming apparatus 1, during image formation in the color mode, yellow (Y), magenta (M), cyan (C), and black (BK) from the high voltage power supply 156 (Y, M, C) for the primary transfer device, which does not exist yellow (Y), magenta (M), and cyan (C). ), the primary transfer bias voltage remains applied to the primary transfer device 15 (Y, M, C), electrical noise is generated, and the color image forming apparatus 1 or peripheral equipment malfunctions. There is a risk that the high-voltage power supplies 156 (Y, M, C) for the yellow (Y), magenta (M), and cyan (C) primary transfer devices will fail.

11A and 11B are circuit diagrams showing equivalent circuits of the intermediate transfer units of the color image forming apparatus and the monochrome image forming apparatus, respectively.

The intermediate transfer unit 200C of the color image forming apparatus 1, as shown in FIG. , M, C, BK) from four high-voltage power supplies 156 (Y, M, C, BK) corresponding to yellow (Y), magenta (M), cyan (C), and black (BK) primary transfer devices R A primary transfer bias current is applied to _BTR-Y , R _BTR-M, R _BTR-C and R _BTR-BK . The primary transfer bias currents supplied to the primary transfer devices R _BTR-Y , R _BTR-M, R _BTR-C , and R _BTR-BK are applied to the intermediate transfer belts R _BELT-Y , R _BELT-M , R _BELT-C , It flows to the ground potential through R _BELT-BK and the photosensitive drums R _DRUM-Y , D _DRUM-M , R _DRUM-C and R _DRUM-BK .

Here, R _BTR-Y , R _BTR-M, R _BTR-C and R _BTR-BK are yellow (Y), magenta (M), cyan (C) and black (BK) primary transfer devices 15 (Y, M, C, BK) are the resistance values of R _BELT-Y , R _BELT-M , R _BELT-C , and R _BELT-BK are the resistance values of the intermediate transfer belt 21, and R _DRUM-Y , D _DRUM-M , R _DRUM-C and R _DRUM-BK represent the resistance values of the yellow (Y), magenta (M), cyan (C) and black (BK) photosensitive drums 11 (Y, M, C, BK), respectively. showing.

On the other hand, the intermediate transfer unit 200M of the monochrome image forming apparatus 2, as shown in FIG. A primary transfer bias current is applied to the transfer device _RBTR-BK . The primary transfer bias current supplied to the primary transfer device R _BTR-BK flows to the ground potential via the intermediate transfer belt R _BELT-BK and the photosensitive drum R _DRUM-BK .

On the other hand, if the monochrome intermediate transfer unit 200M is mistakenly installed in the color image forming apparatus 1, yellow (Y), magenta (M), cyan (C) and Yellow (Y), magenta (M), and cyan (Y), magenta (M), and cyan ( C) and black (BK) primary transfer devices R _BTR-Y , R _{BTR-M ,} R _BTR-C , and R _BTR-BK are to be supplied with primary transfer bias current, but the primary transfer devices ), there is only the primary transfer device R _BTR-BK .

Therefore, in the black (BK) image forming device 10BK, the primary transfer bias current supplied to the black (BK) primary transfer device R _BTR-BK is applied to the intermediate transfer belt R _BELT-BK and the photosensitive drum R _DRUM- It flows through _BK to the ground potential.

However, in the yellow (Y), magenta (M), and cyan (C) image forming devices 10 (Y, M, C), the yellow (Y), magenta (M), and cyan (C) image forming devices 10 (Y, M, C) from three high-voltage power supplies 156 (Y, M, C) corresponding to yellow (Y), magenta (M), cyan (C) and black (BK) primary transfer devices _RBTR Since the primary transfer devices R _BTR-Y , R _{BTR-M , and} R _BTR-C do not exist in _-Y 1 , R _{BTR-M ,} and R _BTR -C, no primary transfer bias current flows.

Therefore, if the monochrome intermediate transfer unit 200M is erroneously installed in the color image forming apparatus 1, yellow (Y), magenta (M), and cyan (C) are transferred during image formation in the color mode, as described above. and from the high-voltage power supply 156 (Y, M, C) for the black (BK) primary transfer device to the non-existing yellow (Y), magenta (M), cyan (C) and black (BK) primary transfer devices The primary transfer bias voltage remains applied, and as described above, electrical noise is generated, causing malfunctions in the color image forming apparatus 1 and peripheral devices, and yellow (Y), magenta (M), and cyan. There is a risk that the high-voltage power supplies 156 (Y, M, C) for the (C) and black (BK) primary transfer devices will fail.

Therefore, in this embodiment, as shown in FIG. 11A, in the color image forming apparatus 1, yellow (Y), magenta (M), cyan (C) and black (BK) image forming devices Voltage sensors 157 (Y, M , C, BK) are provided in parallel. The detection results of the voltage sensors 157 (Y, M, C, BK) are converted into digital values and input to the control section 101 of the control device 100, as shown in FIG.

The control unit 101 of the control device 100 detects the primary transfer voltage applied to the primary transfer device 15 (Y, M, C, BK) by the voltage sensor 157 (Y, M, C, BK), thereby forming a color image. It has a function as a determination means for determining whether or not the intermediate transfer unit 200C for color is suitable for the forming apparatus 1 .

Further, as shown in FIG. 13, the control section 101 of the control device 100 controls the image forming operation of the color image forming apparatus 1 according to the determination result of the color or monochrome intermediate transfer units 200C and 200M. .

<Operation of Characteristic Portion of Image Forming Apparatus>
In the image forming apparatus according to this embodiment, as compared to the case where the discriminating means for discriminating between the intermediate transfer unit for color and the intermediate transfer unit for monochrome is not provided as follows, the intermediate transfer unit is incorrectly selected. determine which is used.

Here, as shown in FIG. 10, a case in which a monochrome intermediate transfer unit 200M is erroneously installed in the color image forming apparatus 1 is described.

As shown in FIG. 13, the control unit 101 in the control device 100 of the color image forming apparatus 1 has an interlock switch that determines whether the power is turned on or the cover for exchanging the intermediate transfer unit is opened or closed. , etc. (step 101). If the power is not turned on or the cover is not opened or closed, the system waits.

On the other hand, when the control unit 101 of the color image forming apparatus 1 determines that the power is turned on or the cover is opened and closed, yellow (Y), magenta (M), cyan (C) and black (BK) are displayed. An operation of detecting the resistance of the primary transfer device 15 (Y, M, C, BK) is performed (step 102). The operation of detecting the resistance of the primary transfer device 15 (Y, M, C, BK) is, as shown in FIG. Four high-voltage power supplies 156 (Y, M, C, BK) corresponding to the respective primary transfer devices 15 (Y, M, C, BK) are operated to transfer yellow (Y), magenta (M), and cyan (C). A predetermined primary transfer bias current is applied to each of the primary transfer devices 15 (Y, M, C, BK) of black (BK) and black (BK). This is done by detecting a primary transfer bias voltage required to apply a determined primary transfer bias current by voltage sensors 157 (Y, M, C, BK). Based on the primary transfer bias current value I and the detected primary transfer bias voltage value V, the controller 101 controls yellow (Y), magenta (M), Resistance corresponding to combined resistance of each primary transfer device 15 (Y, M, C, BK) of cyan (C) and black (BK), intermediate transfer belt 21 and photosensitive drum 11 (Y, M, C, BK) A value R (=V/I) is calculated.

Next, the control unit 101 of the color image forming apparatus 1 controls the primary transfer devices 15 (Y, M, C, BK) of yellow (Y), magenta (M), cyan (C), and black (BK), intermediate transfer devices 15 It is determined whether or not the resistance value R (Y, M, C, BK) corresponding to the combined resistance of the transfer belt 21 and the photosensitive drum 11 (Y, M, C, BK) is equal to or less than a threshold value (step 103). .

The control unit 101 of the color image forming apparatus 1 controls the primary transfer devices 15 (Y, M, C, BK) of yellow (Y), magenta (M), cyan (C), and black (BK), intermediate transfer devices 15 If it is determined that the resistance value R (Y, M, C, BK) corresponding to the combined resistance of the belt 21 and the photosensitive drum 11 (Y, M, C, BK) is equal to or less than the threshold value, the determination result is regarded as normal. (Step 104), the warning display is canceled and the printing inhibition process is canceled (Step 105), color and monochrome image forming operations are enabled, and this control ends.

On the other hand, the control unit 101 of the color image forming apparatus 1 controls the primary transfer devices 15 (Y, M, C, BK) of yellow (Y), magenta (M), cyan (C), and black (BK), intermediate transfer devices 15 If any one of the resistance values R (Y, M, C, BK) corresponding to the combined resistance of the belt 21 and the photosensitive drums 11 (Y, M, C, BK) is not equal to or less than the threshold, black (BK ), the resistance value corresponding to the combined resistance of the primary transfer device 15BK, the intermediate transfer belt 21, and the photosensitive drum 11BK is less than or equal to the threshold value, and the yellow (Y), magenta (M), and cyan (C) primary transfer devices 15 (Y, M, C), the intermediate transfer belt 21, and the photosensitive drum 11 (Y, M, C) exceed a threshold value (step 106).

The control unit 101 of the color image forming apparatus 1 determines that the resistance value corresponding to the combined resistance of the black (BK) primary transfer device 15BK, the intermediate transfer belt 21, and the photosensitive drum 11BK is equal to or less than a threshold, and yellow (Y), The resistance value corresponding to the combined resistance of the magenta (M) and cyan (C) primary transfer devices 15 (Y, M, C), the intermediate transfer belt 21, and the photosensitive drums 11 (Y, M, C) exceeds the threshold. If it is judged that the number exceeds the limit, the judgment result is regarded as an erroneous set (step 107), a warning display is displayed on the display unit 103b, color printing operation is prohibited (step 108), and only monochrome image forming operation is performed. End this control as possible.

Here, as a warning display displayed on the display unit 103b of the color image forming apparatus 1, for example, a message such as "Intermediate transfer unit is not installed correctly. Please replace with a regular intermediate transfer unit." Is displayed.

Further, the control unit 101 of the color image forming apparatus 1 may prohibit all printing operations, or may allow only the monochrome mode using the black image forming apparatus 10BK. Furthermore, when the color mode is specified, the control unit 101 of the color image forming apparatus 1 may convert the gradation of the color image into a grayscale representing monochrome, and then execute the print operation in the monochrome mode. . At that time, the display section 103b of the color image forming apparatus 1 displays to that effect.

The control unit 101 of the color image forming apparatus 1 holds the color print inhibiting operation until the next discrimination operation sequence is executed. Then, when the controller 101 of the color image forming apparatus 1 determines that the regular color intermediate transfer unit 200C is mounted when executing the next determination operation sequence, the controller 101 of the operation unit 103 displays the display unit 103a of the operation unit 103. The warning display for , and the prohibited operation of color printing are cancelled.

In addition, the control unit 101 of the color image forming apparatus 1 determines that the resistance value corresponding to the combined resistance of the black (BK) primary transfer device 15BK, the intermediate transfer belt 21, and the photosensitive drum 11BK is not equal to or less than the threshold value, or the yellow (Y ), magenta (M), and cyan (C) primary transfer devices 15 (Y, M, C), intermediate transfer belt 21, and photosensitive drums 11 (Y, M, C). If it is determined that the threshold is not exceeded, it is determined that the detection result is not normal, and the process returns to step 102 .

Thus, in the first embodiment, as shown in FIG. 10, when the monochrome intermediate transfer unit 200M is erroneously installed in the color image forming apparatus 1, yellow (Y), magenta (M), yellow (Y), magenta (M), By determining the resistance value corresponding to each of the cyan (C) primary transfer devices 15 (Y, M, C), it is possible to determine that the intermediate transfer unit 200M is misassembled.

Therefore, in the color image forming apparatus 1, by prohibiting color printing, the high-voltage power supply 156 (for yellow (Y), magenta (M), cyan (C), and black (BK) for the primary transfer device is used during image formation. A primary transfer bias voltage is applied to the primary transfer devices 15 (Y, M, C) of nonexistent yellow (Y), magenta (M), cyan (C), and black (BK). This causes electrical noise to occur, causing malfunctions in the color image forming apparatus 1 and peripheral devices, and primary transfer devices for yellow (Y), magenta (M), cyan (C) and black (BK). This avoids the risk of failure of the high-voltage power supplies 156 (Y, M, C) for

Further, the control unit 101 of the color image forming apparatus 1 does not prohibit all printing operations, but only color printing, and enables monochrome printing using the black imaging device 10BK. convenience is guaranteed.

[Embodiment 2]
FIG. 14 is a circuit diagram showing an equivalent circuit of a primary transfer device of a monochrome image forming apparatus as an example of the image forming apparatus according to the second embodiment.

That is, in the second embodiment, as shown in FIG. 14, a plurality of or multiple It is configured to include a control section 301 as a determination means for determining which of the single primary transfer units is the color or monochrome intermediate transfer unit 200C or 200M.

In the second embodiment, as shown in FIG. 14, the monochrome image forming apparatus 2 is configured to convert the black (BK) primary transfer device 15BK from the high voltage power supply 156BK of the black (BK) primary transfer device 15BK to the adjacent cyan transfer device 15BK. A changeover switch 158 is provided for selectively energizing the primary transfer device 15C. Further, the second apparatus main body 2a is provided with a ground circuit 159 for contacting the outer peripheral surface of the cyan primary transfer device 15C and connecting it to the ground potential when the color intermediate transfer unit 200C is erroneously installed. It is The ON/OFF state of the changeover switch 158 is switched by the control unit 301 of the monochrome image forming apparatus 2 .

FIG. 15 is a block diagram showing the control device 300 of the monochrome image forming apparatus 2 according to the second embodiment.

The control device 300 includes a control section 301 as an example of determination means, a storage section 302 and an operation section 303 .

The control unit 301 executes programs stored in the storage unit 302 and controls the image forming operation of the monochrome image forming apparatus 2 . The control unit 301 controls the storage unit 302 and the operation unit 303, and communicates with a user's personal computer (not shown) or the like via a communication unit (not shown).

The operation unit 303 has an input unit 303a for the user to input the type of the recording paper 5, the number of prints, and the like, and an input unit 303a for instructing the start of the image forming operation by pressing a start button. A display unit 303b is provided as an example of notification means for displaying a message or the like.

The control unit 301 includes a high-voltage power supply 156BK that applies a primary transfer bias voltage to the black (BK) primary transfer device 15BK, and a voltage sensor 157BK that detects the primary transfer bias voltage applied to the primary transfer device 15BK by the high-voltage power supply 156BK. is connected.

A switch 158 is connected to the control unit 301, and the ON/OFF state of the switch 158 is switched.

In the second embodiment, the controller 301 determines whether the power is turned on or whether the cover for exchanging the intermediate transfer unit is opened or closed based on a signal from an interlock switch or the like.

When the control unit 301 determines that the power is turned on or the cover for exchanging the intermediate transfer unit is opened and closed, as shown in FIG. switch to the side.

In the monochrome image forming apparatus 2, as shown in FIG. 14A, when the monochrome intermediate transfer unit 200M is properly installed, the cyan primary transfer device 15C does not exist, so the current is supplied from the high voltage power supply 156BK. does not flow.

On the other hand, as shown in FIG. 14(b), when the color intermediate transfer unit 200C is installed in the monochrome image forming apparatus 2, the voltage from the high voltage power supply 156BK to the ground potential through the cyan primary transfer device 15C is applied. current flows.

When the control unit 301 switches the changeover switch 158 to the cyan primary transfer device 15C side, the voltage is detected by the voltage sensor 157BK when a current flows from the high voltage power supply 156BK to the ground potential through the cyan primary transfer device 15C. be.

As a result, when the voltage is detected by the voltage sensor 157BK when the changeover switch 158 is switched to the cyan primary transfer device 15C side, the controller 301 detects the color intermediate transfer device in which the cyan primary transfer device 15C is present. It is determined that the unit 200C is attached.

As shown in FIG. 15, the control unit 301 displays a message such as "Intermediate transfer unit is not installed correctly. Replace with a regular intermediate transfer unit." do.

As described above, the monochrome image forming apparatus 2 does not cause any operational problems even if the color intermediate transfer unit 200C is erroneously installed. However, in the above-described second embodiment, it is possible to determine that the color intermediate transfer unit 200C is erroneously attached to the monochrome image forming apparatus 2, and the user selects the appropriate monochrome intermediate transfer unit 200M. It is possible to encourage use.

In the above-described embodiment, a constant-current power supply is used as the high-voltage power supply, and the primary transfer bias voltage applied by the high-voltage power supply is detected by a voltage sensor. Alternatively, a current sensor may be used to detect the primary transfer bias current supplied by the high-voltage power supply.

1 Color image forming apparatus 1a First apparatus main body 10Y to 10BK Full-color image forming apparatus 11Y to 11BK Photoreceptor drums 15Y to 15BK Primary transfer image forming apparatus 100 Control device 101 Control section 156Y to 156BK High voltage Power source 157Y to 157BK Voltage sensor 2 Monochrome image forming apparatus 2a Second apparatus main body 200C Color intermediate transfer unit 200M Monochrome intermediate transfer unit 300 Control device 301 Control section

Claims (6)

It is configured to be attachable/detachable to both a first apparatus main body having a plurality of image holding means and a second apparatus main body having a single image holding means, and images are respectively held by the image holding means of the first or second apparatus main body. an intermediate transfer means having multiple or single transfer means for transferring;
determining means for determining whether or not the intermediate transfer means is suitable by detecting current or voltage applied to the transfer means;
with
An image forming apparatus comprising: a notifying means for notifying a user of the determination result when the determination means determines that the intermediate transfer means having the single transfer means is attached to the first apparatus main body . 2. The image forming apparatus according to claim 1, further comprising switching means provided in said first apparatus main body for switching transfer operations by said plurality of transfer means based on the determination result of said determining means. When the discriminating means discriminates that the intermediate transfer means having the single transfer means is attached to the first apparatus main body, the switching means selects a transfer means corresponding to one transfer means among the plurality of transfer means. 3. The image forming apparatus according to claim 1 , wherein only the operation is switched to be executable. a discriminating means provided in the second apparatus main body for discriminating whether the intermediate transfer means has one of the plurality of transfer means or the single transfer means by detecting a current or voltage applied to the transfer means;
The image forming apparatus according to claim 1, comprising: 5. The image forming apparatus according to claim 4 , further comprising notifying means for notifying a user of the determination result when the determination means determines that the intermediate transfer means having the plurality of transfer means is attached to the second apparatus main body. . The discriminating means supplies current or voltage to the transfer means from a plurality of or a single power supply via a current path for conducting a transfer current between the plurality or the single image holding means and the transfer means. 6. The image forming apparatus according to any one of claims 1 to 5 , which detects .

Images