JP2011059159A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of detecting a grounding state of an attaching and detaching member detachably formed for an image forming apparatus body in a simple configuration without applying a high voltage. <P>SOLUTION: The image forming apparatus includes: the image forming apparatus body 100 having a control means MCU including a reference grounding point and for controlling configuration devices; and the attaching and detaching member CRU detachably formed for the image forming apparatus body 100. The attaching and detaching member CRU is connected to the reference grounding point when being mounted on the image forming apparatus body 100, includes a continuous quantity input terminal capable of inputting the grounding state as a continuous physical quantity, and has a continuous quantity input and output means capable of being output to the control means MCU of the image forming apparatus body 100. Meanwhile, the control means MCU of the image forming apparatus body 100 discriminates the grounding state of the attaching and detaching member CRU on the basis of output result of the continuous quantity input and output means without applying an additional high voltage for detecting the grounding state of the attaching and detaching member CRU. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ground (connection) configuration of an image forming apparatus.

  Conventionally, in an image forming apparatus such as a copying machine or a printer using an electrophotographic system, replacement parts such as a photosensitive drum, a charging device, and a developing device are integrated into a unit so that the image forming apparatus can be attached to and detached from the main body. A so-called process cartridge type image forming apparatus is known. In general, when the detachable unit made into a cartridge (unitized) in this way is mounted on the image forming apparatus main body, the component device on the detachable unit side is grounded, and this grounding state is detected. A ground detection method has been proposed (see, for example, Patent Documents 1 to 4).

  Here, Patent Documents 1 to 4 disclose image forming apparatuses that detect a grounding state by monitoring an output current of a high-voltage power source applied to a photosensitive drum, a charging roll, a developing roll, and the like.

JP 2003-223091 A JP 2002-333811 A JP 2002-333812 A JP 2000-194246 A

  An object of the present invention is to provide an image forming apparatus capable of detecting the grounding state of a detachable member formed to be detachable from the image forming apparatus main body with a simple configuration without applying a high voltage. It is to be.

The image forming apparatus according to claim 1 includes an image forming apparatus main body including a reference grounding point and having a control unit that controls the constituent devices, and a detachable member formed to be detachable from the image forming apparatus main body. The detachable member includes a continuous quantity input terminal that is connected to the reference grounding point when mounted on the image forming apparatus main body and allows the grounded state to be input as a continuous physical quantity. The image forming apparatus main body control means does not apply an additional high voltage for detecting the grounding state of the detachable member, while the image forming apparatus main body control means has continuous amount input / output means that can output to the control means of the apparatus main body. The grounding state of the detachable member is determined based on the output result of the continuous amount input / output means.
According to a second aspect of the present invention, in the configuration according to the first aspect, the continuous amount input / output unit is a CPU unit provided in an attachment / detachment member, and the attachment / detachment member has a ground potential of the attachment / detachment. It is input to an analog port provided on the member.
The image forming apparatus according to claim 3 includes an image forming apparatus main body including a reference grounding point and having a control unit that controls the constituent devices, and a detachable member formed to be detachable from the image forming apparatus main body. A plurality of the detachable members are provided to the image forming apparatus, and are connected to the reference grounding point when mounted on the image forming apparatus main body. Connected to a common continuous quantity input terminal provided on the image forming apparatus main body side, which enables the grounding state to be input as a continuous physical quantity, and the control means of the image forming apparatus main body is connected to the grounding state of the detachable member The grounding state of each of the detachable members is determined based on the continuous amount input to the continuous amount input terminal without applying an additional high voltage for detecting A.
According to a fourth aspect of the present invention, in the configuration of the third aspect, the plurality of detachable members are connected to a common analog port provided in the main body of the image forming apparatus via a resistor. The resistance value of the resistor is set to be different for each detachable member.
According to a fifth aspect of the present invention, in the configuration according to the first to fourth aspects, the control unit of the main body of the image forming apparatus discriminates the grounding state of the detachable member by dividing into three or more stages. It is characterized by doing.

  According to the first aspect of the present invention, existing components can be used without applying an additional high voltage for detection, and the grounding state of the detachable member can be determined with a simple configuration.

  According to the second aspect of the present invention, it is possible to determine the ground state in multiple stages with respect to a single analog input.

  According to the third aspect of the present invention, the existing components can be used without applying an additional high voltage for detection, and the grounding states of the plurality of detachable members are determined with a simple configuration. be able to.

  According to the fourth aspect of the present invention, it is possible to reliably determine the grounding state of each of the plurality of detachable members with a simple configuration.

  According to the fifth aspect of the present invention, not only normal / abnormal of the grounding state but also the intermediate state can be determined, and the convenience for the user can be improved.

1 is a schematic configuration diagram illustrating a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention is applicable. 3 is a schematic diagram for explaining a ground (connection) configuration of the image forming apparatus according to Embodiment 1. FIG. (A) is a flowchart for explaining the procedure for determining the ground state of the image forming apparatus according to the present embodiment, and (b) is a schematic diagram for explaining the contents of each threshold value. FIG. 6 is a schematic diagram for explaining a ground (connection) configuration of an image forming apparatus according to a second embodiment.

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

  First, the configuration of an image forming apparatus to which the present invention can be applied will be described with reference to FIG. Here, FIG. 1 is a configuration diagram showing a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention is applicable. Although this tandem type color electrophotographic copying machine is provided with an image reading device, the image forming device is not provided with an image reading device and is based on image data output from a personal computer (not shown) or the like. It may be a color printer, a facsimile, or the like that forms an image.

  In FIG. 1, reference numeral 100 denotes a main body of a tandem type digital color copying machine 1 as an example of an image forming apparatus to which the present invention can be applied. An automatic document conveying device 3 that automatically conveys the document in a state and a document reading device 4 that reads an image of the document 2 conveyed by the automatic document conveying device 3 are arranged. The document reader 4 illuminates a document 2 placed on a platen glass 5 with a light source 6, and reflects a reflected light image from the document 2 from a full-rate mirror 7, half-rate mirrors 8 and 9, and an imaging lens 10. The image reading element 11 made of a CCD or the like is scanned and exposed through a reduction optical system, and the image material 11 reflects the color material reflected light image of the original 2 by a predetermined dot density (for example, 16 dots / mm). ).

  The color material reflected light image of the document 2 read by the document reading device 4 is subjected to image processing, for example, as document reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). The image processing apparatus 12 sends images such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color / moving editing, etc. to the reflectance data of the document 2. Processing is performed. In addition, the image processing device 12 performs predetermined image processing on image data sent from a personal computer or the like.

  The image data that has been subjected to the predetermined image processing by the image processing device 12 as described above is processed by the image processing device 12 in the same manner as yellow (Y), magenta (M), cyan (C), and black (K). (8 bits each) is converted into four-color original reproduction color material gradation data, and as described below, image formation of each color of yellow (Y), magenta (M), cyan (C), and black (K) The images are sent to the exposure devices 14 of the units 13Y, 13M, 13C, and 13K, and the exposure device 14 performs image exposure with the laser beam LB in accordance with the original reproduction color material gradation data of each color.

  Inside the tandem type digital color copying machine main body 100, four image forming units 13Y, 13M, 13C, and 13K of yellow (Y), magenta (M), cyan (C), and black (K) are horizontally arranged. They are arranged in parallel at regular intervals in the direction.

  These four image forming units 13Y, 13M, 13C, and 13K are all configured in the same manner, and are roughly divided into a photosensitive drum 15 as an image carrier that is rotationally driven at a predetermined speed, and the photosensitive drum. A charging device 16 for primary charging that uniformly charges the surface of 15, an exposure device 14 including a scanning optical system that exposes an image corresponding to each color on the surface of the photosensitive drum 15 to form an electrostatic latent image, and The image forming apparatus includes a developing device 17 that develops the electrostatic latent image formed on the photosensitive drum 15 with each color toner, a drum cleaning device 18 that cleans the surface of the photosensitive drum 15, and the like. The image forming units 13Y, 13M, 13C, and 13K according to the present embodiment are formed as detachable units (detachable members) that are detachably formed on the image forming apparatus main body 100.

  The exposure device 14 is configured in common to the image forming units 13Y, 13M, 13C, and 13K for each color of yellow (Y), magenta (M), cyan (C), and black (K). The semiconductor laser is modulated in accordance with the color reproduction gradation material reproduction data for each color, and laser beams LB-Y, LB-M, LB-C, and LB-K are emitted from these semiconductor lasers in accordance with the gradation data. It is configured as follows. Of course, the exposure apparatus 14 may be individually configured for each of a plurality of image forming units. The laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the semiconductor laser are irradiated to the rotary polygon mirror 19 through an f-θ lens (not shown) and deflected by the rotary polygon mirror 19. Scanned. The laser beams LB-Y, LB-M, LB-C, and LB-K deflected and scanned by the rotary polygon mirror 19 are scanned and exposed from below on the photosensitive drum 15 through a plurality of reflection mirrors (not shown). Is done.

  The exposure apparatus 14 according to the present embodiment is hermetically sealed by a rectangular parallelepiped frame 20, and four laser beams LB-Y, LB-M, and LB-C are provided above the frame 20. , LB-K are exposed on the photosensitive drums 15Y, 15M, 15C, 15K of the image forming units 13Y, 13M, 13C, 13K, so that transparent glass windows 21Y, 21M, 21C, 21K as shield members are used. Is provided. These glass windows 21Y, 21M, 21C, and 21K are members that are located at the uppermost position on the optical path along the laser beam LB of the exposure apparatus 14.

  In the present embodiment, yellow (Y), magenta (M), cyan (C), and black (K) developing devices 17Y, 17M, 17C, and 17K are disposed above the intermediate transfer belt 25. Toner cartridges 50Y, 50M, 50C, and 50K for supplying a predetermined color developer (mainly toner or toner containing a carrier) are arranged.

  In the four image forming units 13Y, 13M, 13C, and 13K, yellow (Y), magenta (M), cyan (C), and black (K) toner images are sequentially formed at predetermined timings, respectively. It is configured as follows. As described above, the image forming units 13Y, 13M, 13C, and 13K for the respective colors include the photosensitive drums 15Y, 15M, 15C, and 15K, and the surfaces of the photosensitive drums 15Y, 15M, 15C, and 15K are primary. The charging devices 16Y, 16M, 16C, and 16K for charging are uniformly charged. Thereafter, image forming laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the exposure device 14 according to image data are applied to the surfaces of the photosensitive drums 15Y, 15M, 15C, and 15K. Scanning exposure is performed to form an electrostatic latent image corresponding to each color. The laser beams LB-Y, LB-M, LB-C, and LB-K scanned and exposed on the photosensitive drums 15Y, 15M, 15C, and 15K are slightly on the right side of the photosensitive drums 15Y, 15M, 15C, and 15K. The exposure is set so as to be exposed at a predetermined inclination angle from the obliquely lower side. The electrostatic latent images formed on the photosensitive drums 15Y, 15M, 15C, and 15K are yellow (Y) and yellow (Y) by the developing devices 17Y, 17M, 17C, and 17K of the image forming units 13Y, 13M, 13C, and 13K, respectively. It is developed as a visible toner image of each color of magenta (M), cyan (C), and black (K).

  Each color of yellow (Y), magenta (M), cyan (C), and black (K) sequentially formed on the photosensitive drums 15Y, 15M, 15C, and 15K of the image forming units 13Y, 13M, 13C, and 13K. The toner images are sequentially transferred in multiple by the primary transfer rolls 26Y, 26M, 26C, and 26K onto the intermediate transfer belt 25 disposed over the image forming units 13Y, 13M, 13C, and 13K. The intermediate transfer belt 25 is wound around the drive roll 27 and the backup roll 28 with a constant tension, and is driven by a drive roll 27 that is rotationally driven by a dedicated drive motor with excellent constant speed (not shown). The circuit is circulated at a predetermined speed in the direction of the arrow. As the intermediate transfer belt 25, for example, a flexible synthetic resin film such as PET is formed in a band shape, and both ends of the synthetic resin film formed in a band shape are connected by means such as welding, thereby endless A belt-shaped one is used.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred onto the intermediate transfer belt 25 in a multiple manner are transferred to the backup roll 28 by a secondary transfer roll 29. The recording paper P, which is secondarily transferred onto the recording paper P by the pressure contact force and electrostatic force, and onto which the toner images of these colors are transferred, is conveyed to the fixing device 30 positioned above. The secondary transfer roll 29 is in pressure contact with the side of the backup roll 28, and secondary-transfers each color toner image onto the recording paper P conveyed from below to above. The recording paper P on which the toner images of the respective colors are transferred is subjected to a fixing process with heat and pressure by the fixing device 30 and then discharged onto a discharge tray 33 provided on the upper portion of the main body 100 by a discharge roll 32. The

  The recording paper P having a predetermined size from the paper feed cassette 34 is once transported to a registration roll 38 via a paper transport path 37 by a paper feed roller 35 and a pair of rollers 36 for paper separation and transport. Stopped. The recording paper P supplied from the paper feed cassette 34 is sent to the secondary transfer position of the intermediate transfer belt 25 by a registration roll 38 that rotates at a predetermined timing.

  In the above-described digital color copying machine, when full-color double-sided copying is performed, the recording paper P with the image fixed on one side is not discharged onto the discharge tray 33 as it is by the discharge roll 32 but is switched not shown. The conveyance direction is switched by the gate, and the sheet is conveyed to the duplex conveyance unit 40 via the sheet conveyance roller pair 39. Then, in the double-sided conveyance unit 40, the recording paper P is conveyed again to the registration roll 38 with the front and back sides of the recording paper P reversed by a pair of conveyance rollers (not shown) provided along the conveyance path 41. Is discharged onto the discharge tray 33 after the image is transferred and fixed on the back surface of the recording paper P.

  Further, after the toner image transfer process is completed, residual toner, paper dust, and the like are removed from the surfaces of the photosensitive drums 15Y, 15M, 15C, and 15K by the drum cleaning devices 18Y, 18M, 18C, and 18K. Prepare for the formation process.

  Further, residual toner, paper dust and the like are removed from the surface of the intermediate transfer belt 25 after the toner image transfer process is completed by the belt cleaning device 43 to prepare for the next image forming process. The belt cleaning device 43 includes a cleaning brush 43a and a cleaning blade 43b, and residual toner and paper dust on the intermediate transfer belt 25 are removed by the cleaning brush 43a and the blade 43b.

  When the image forming units (detachable units) 13Y, 13M, 13C, and 13K are configured to be detachable from the image forming apparatus main body 100 as described above, the removable units 13Y, 13M, 13C, and 13K are connected to the apparatus main body. When attached to 100, it is necessary to ground the necessary components. Conventionally, in order to detect the connection (grounding) state between the detachable units 13Y, 13M, 13C, and 13K and the image forming apparatus main body 100, the photosensitive drums 15Y, 15M, 15C, and 15K, the charging devices 16Y, The detachable unit 13Y is detected by detecting an output current value of a component device to which a high voltage (for example, 1,000 to 3,000 V) such as 16M, 16C, 16K or developing devices 17Y, 17M, 17C, 17K is applied. , 13M, 13C, and 13K (high voltage application method) is used. However, in such a high voltage application method, there is a possibility that leakage or electromagnetic noise may occur when the connection state between the detachable units 13Y, 13M, 13C, and 13K and the image forming apparatus main body 100 is insufficient. Moreover, since a high-voltage detection circuit is separately required, there has been a problem that the cost is increased.

Therefore, in the image forming apparatus 1 according to the present embodiment, a high voltage application for detecting the grounding state of the detachable units 13Y, 13M, 13C, and 13K and a high voltage detection circuit associated therewith are not required. Therefore, the grounded state of the detachable units 13Y, 13M, 13C, and 13K can be detected with a simple configuration by using existing components.
<Embodiment 1>

  The ground (connection) configuration of the image forming apparatus according to the first embodiment will be described below with reference to FIG. Here, FIG. 2 is a schematic diagram for explaining a ground (connection) configuration of the image forming apparatus according to the present embodiment. For the sake of simplification, the image forming apparatus main body 100 described below will be described as an image forming apparatus main body 100 for a color printer that does not include the document reading device 4 and the double-sided conveyance unit 40 described above, and the image. A detachable unit (in this example, an image forming unit) detachably formed on the forming apparatus main body 100 is denoted as CRU.

  As schematically illustrated in FIG. 2, the image forming apparatus main body 100 according to the present embodiment includes constituent devices (for example, a charging device 16, an exposure device 14, a developing device 17, a transfer device 26, and a fixing device 30). A device controller (control means) MCU including a CPU unit to be controlled is provided, and a reference ground point (a ground point serving as a reference for the ground potential) is provided at a predetermined position of the main body frame. In the present embodiment, a bearing (drum contact) DG connected to one end of the rotating shaft 15S of the photosensitive drum 15 included in the detachable unit CRU is connected to the reference ground point, and the detachable unit CRU is connected to the detachable unit CRU. When normally mounted on the image forming apparatus main body 100, the ground potential of each component device is configured to be in a normal range (allowable range).

  On the other hand, the detachable unit CRU according to the present embodiment includes a microcomputer chip as a semiconductor element having a memory, an analog port (continuous amount input terminal), etc., and the detachable unit CRU is mounted on the image forming apparatus main body 100. When the rotating shaft 15S of the photosensitive drum 15 is connected to the bearing portion DG on the image forming apparatus main body 100 side, the connection state information is directly taken into the analog port and the microcomputer of the detachable unit CRU (hereinafter also referred to as the unit side CPU). And an apparatus controller MCU on the image forming apparatus main body 100 side so that data communication is possible.

  Here, the unit side CPU including the analog port (continuous amount input terminal) and the communication control circuit constitutes the continuous amount input / output means according to the present embodiment. In general, the unit-side CPU, for example, in order to connect information such as the life cycle count of the photosensitive drum 15 with other devices (for example, communication connection with the device controller MCU of the image forming apparatus main body 100), It is mounted on the detachable unit CRU. Therefore, the continuous quantity input / output means according to the present embodiment can be easily configured by using an existing CPU unit provided on the detachable unit CRU side.

  FIG. 3 is a flowchart or the like for explaining the determination procedure of the grounding state of the image forming apparatus according to the present embodiment.

  As shown in FIG. 3A, first, at the time of machine standby, the unit side CPU detects the ground potential (analog port potential) of the photosensitive drum 15 (step ST10).

  If the detected potential is less than a predetermined threshold A, a printable display is performed on a display unit provided in the image forming apparatus main body 100, and a printable state is set (step ST12).

  On the other hand, if the detected potential is greater than or equal to the threshold A, a display prompting the user to attach the detachable unit CRU is again displayed on the display unit, and the ground potential is detected again (step ST14).

  If the ground potential is detected again in step ST14 and the detected potential is less than the threshold value A, it is determined that the normal connection (ground) state has been restored, and the ground potential is provided in the image forming apparatus main body 100. A display indicating that printing is possible is performed on the display unit, and a printable state is set (step ST16).

  On the other hand, if the detected potential is greater than or equal to threshold A in step ST14, it is further determined whether or not the ground potential is less than threshold B (step ST18). If it is, it is determined that the detachable unit CRU has reached the end of its life, and a display prompting replacement of the detachable unit CRU is performed (step ST20).

  On the other hand, if the detected potential is greater than or equal to the threshold value B in step ST18, it is determined as a structural defect such as breakage, and a display prompting machine repair is performed (step ST22).

  Here, the threshold values A and B (threshold value A <threshold value B in this example) are set so that the ground potential range that does not interfere with image formation is less than the threshold value A, as shown in FIG. ing. Also, when the detachable unit CRU reaches the end of its life (deteriorates over time), the ground potential rises due to wear, toner adhesion, etc., so the threshold A or more and less than B is the detection range of the detachable unit mounting failure or the life (due to increased ground potential). The threshold value B or higher is set as the defect detection range on the mechanical structure. Note that the set number of threshold values, the set value, and the like can be arbitrarily selected according to the characteristics of the detection target.

Thus, the ground potential when the detachable unit CRU is connected to the image forming apparatus main body 100 is provided on the image forming apparatus main body 100 side via the unit side CPU including the analog port provided on the detachable unit CRU side. In the conventional control unit MCU, a single detection point DG (in this example, without applying a high voltage for detecting a ground state or providing a special detection circuit separately, as in the past). Further, the grounding (connection) state of the detachable unit CRU can be detected with a simple configuration by the one end portion in the axial direction of the photosensitive drum 15.
In addition, since the analog level can be detected more stably than the method that applies high voltage, it is possible to detect the connection (grounding) status of multiple stages (3 or more stages) with a single analog port. Is possible. In other words, in the image forming apparatus 1 according to the present embodiment, not only the normal / abnormal binary state determination, but also the state that requires replacement of the removable unit CRU in the intermediate state (life of the removable unit CRU), etc. A connection state divided into stages or more can be detected by a single analog port.
<Embodiment 2>

  Next, a ground (connection) configuration of the image forming apparatus according to the second embodiment will be described with reference to FIG.

  In the image forming apparatus according to the present embodiment, a plurality of detachable units CRU are connected to a single analog port, and members having the same functions as those of the previous embodiment are denoted by the same reference numerals. Detailed description thereof is omitted.

  FIG. 4 is a schematic diagram for explaining a ground (connection) configuration of the image forming apparatus according to the second embodiment. In the image forming apparatus 1 according to the present embodiment, a plurality of detachable units CRU (Y), CRU (M), CRU (C), and CRU corresponding to at least each color (yellow, magenta, cyan, and black in this example). (K) is connected to a common (single) analog port provided in the apparatus controller MCU on the image forming apparatus main body 100 side, and the common line CL connected to the analog port and each detachable unit CRU (Y ), CRU (M), CRU (C), and CRU (K) are connected through resistors R1, R2, R3, and R4 having different resistance values, respectively.

  The common line CL is connected to a low-voltage power source V0 (for example, 3.3 to 5 V) having a signal level via a pull-up resistor R0. The detachable units CRU (Y) and CRU (M) , CRU (C) and CRU (K) are connected. Note that the CPU drive power source of the device controller MCU can be used as the low voltage power source.

  Specifically, when each of the detachable units CRU (Y), CRU (M), CRU (C), and CRU (K) is normally connected to the image forming apparatus main body 100, the potential of the analog port is ( A predetermined voltage value Va as shown in Expression 1) is obtained, and thereby, it is determined that the grounding state of each of the detachable units CRU (Y), CRU (M), CRU (C), and CRU (K) is normal. It has become.

  Va = V0 * Ra / (R0 + Ra) (Formula 1)

  Here, Ra is a combined resistance value of R1 to R4, and is calculated by Ra = R1 * R2 * R3 * R4 / (R2 * R3 * R4 + R1 * R3 * R4 + R1 * R2 * R4 + R1 * R2 * R3). .

  On the other hand, when the connection state of any of the attachment / detachment units CRU is abnormal, the resistors R1, R2, R3 connecting the attachment / detachment units CRU (Y), CRU (M), CRU (C), and CRU (K). , R4 have different resistance values, and as illustrated in (Equation 2), a specific voltage value Vb corresponding to the abnormally connected / removable unit CRU is detected at the analog port. Therefore, based on the detected value, it is determined which of the attachment / detachment units CRU (Y), CRU (M), CRU (C), and CRU (K) is abnormal.

  Vb = V0 * Rb / (R0 + Rb) (Formula 2)

  Here, Rb is a combined resistance value when, for example, one of the attachment / detachment units CRU causes a ground failure and the resistance value corresponding to the attachment / detachment unit CRU becomes infinite (open).

  The combined resistance value Rb differs depending on which attachment / detachment unit CRU has an abnormality (which attachment / detachment unit CRU is opened), so the voltage value Vb at the analog port corresponding to the failure mode is stored in a memory in advance as a table. By doing so, the detachable unit CRU having an abnormal connection (grounding) can be easily identified.

  The unit devices connected to the common line CL are not limited to the image forming units 13Y, 13M, 13C, and 13K, and may be, for example, a feeder unit or a double-sided unit, or any other ground that requires grounding. Part.

  The technical scope of the present invention is not limited to the above-described embodiments, and various modifications or improvements can be added without departing from the scope of the present invention described in the claims. For example, by using an analog port, it becomes possible to determine the ground state in multiple stages with respect to a single input. Therefore, the number of set thresholds is increased in Embodiment 1 to determine the ground state more finely. Alternatively, a plurality of threshold values may be provided in the second embodiment, and the grounding state of each detachable unit CRU may be determined in three or more stages.

1: image forming apparatus, 4: document reading apparatus, 12: image processing apparatus, 13Y, 13M, 13C, 13K: image forming unit, 14Y, 14M, 14C, 14K: exposure apparatus, 15Y, 15M, 15C, 15K: photosensitive Drum, 15S: rotating shaft, 16Y, 16M, 16C, 16K: charging device, 17Y, 17M, 17C, 17K: developing device, 18Y, 18M, 18C, 18K: drum cleaning device, 25: intermediate transfer belt, 26Y, 26M , 26C, 26K: primary transfer roll, 27: drive roll, 28: backup roll, 29: secondary transfer roll, 30: fixing device, 34: paper feed cassette, 40: duplex transport unit, 43: belt cleaning device, 50Y, 50M, 50C, 50K: toner cartridge, 100: image forming apparatus main body, CRU: De Unit, MCU: apparatus controller, CL: common line R0, R1, R2, R3, R4: resistance, Ra, Rb: combined resistance value, V0: low-voltage power supply, Va, Vb: Voltage value, P: recording paper

Claims (5)

An image forming apparatus main body including a reference ground point and having a control means for controlling the constituent devices;
A detachable member formed detachably with respect to the image forming apparatus main body,
The detachable member is connected to the reference ground point when mounted on the image forming apparatus main body, and includes a continuous quantity input terminal that allows the grounded state to be input as a continuous physical quantity. While having continuous quantity input / output means enabling output to the control means,
The control unit of the image forming apparatus main body is configured to ground the detachable member based on the output result of the continuous amount input / output unit without applying an additional high voltage for detecting the ground state of the detachable member. An image forming apparatus characterized by determining a state.   2. The continuous amount input / output means is a CPU unit provided in a detachable member, and the ground potential of the detachable member is input to an analog port provided in the detachable member. The image forming apparatus described. An image forming apparatus main body including a reference ground point and having a control means for controlling the constituent devices;
A detachable member formed detachably with respect to the image forming apparatus main body,
A plurality of the detachable members are provided with respect to the image forming apparatus, and are connected to the reference grounding point when attached to the image forming apparatus main body, and each of the plurality of detachable members has a grounded state. Connected to a common continuous quantity input terminal provided on the image forming apparatus main body side, which enables input as a continuous physical quantity,
The control unit of the image forming apparatus main body may be configured such that the detachable member is based on a continuous amount input to the continuous amount input terminal without applying an additional high voltage for detecting a grounding state of the detachable member. An image forming apparatus that determines a grounding state of each.   The plurality of attachment / detachment members are connected to a common analog port provided in the image forming apparatus main body via a resistor, and the resistance value of the resistor is set so that the value differs for each attachment / detachment member. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus.   5. The image forming apparatus according to claim 1, wherein the control unit of the image forming apparatus main body determines the grounding state of the detachable member by dividing into three or more stages.

Images