JP2009086442A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus effectively using a detecting mechanism. <P>SOLUTION: A developing cartridge 16 includes a projection part 42 to be moved by input of a driving force. The projection part 42 moves through a detecting position of a new detection switch 43. The developing cartridge 16 is displaced between a pressure contact position and a separated position by a displacement mechanism 30. According to the displacement of the developing cartridge 16, a gear body 41 of a new detection gear 40 is displaced within a range including the detecting position of the switch 43. Therefore, the passage of the projection 42 through the detecting position of the switch 43 and the position of the developing cartridge 16 can be determined based on the state of a detection signal outputted from the switch 43. Accordingly, the switch 43 can be effectively used for the two determinations. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a laser printer.

In an image forming apparatus such as a laser printer, a developing cartridge that accommodates toner is configured to be detachable from the apparatus main body, and is a new cartridge installed in the apparatus main body for managing the number of printable sheets? Some have a function of discriminating whether it is an old product (used even a little).
As such an image forming apparatus, for example, a reflection type optical sensor is provided in the main body of the apparatus, and based on the output of the reflection type optical sensor, it is proposed to determine whether the developing cartridge is new or old. (For example, refer to Patent Document 1). In the image forming apparatus according to this proposal, the development cartridge is provided with a new / old detection gear, and the new / old detection gear is driven to rotate during a warm-up operation that is triggered by turning on the power only when the development cartridge is new. It has become so. Then, during a predetermined period during the warm-up operation, the detection light from the light emitting part of the reflective optical sensor is blocked by the old and new detection gear with the rotation of the old and new detection gear, and the light receiving part of the reflective optical sensor receives the detection light. If not, it is determined that the developing cartridge is new. On the other hand, if the reflective optical sensor receives detection light during the predetermined period, it is determined that the developing cartridge is an old product.
JP 2007-148285 A

However, the determination of whether the developing cartridge is new or old is completed in a predetermined period during the warm-up operation, and the reflective optical sensor is not used at a time other than during the warm-up operation. Therefore, it cannot be said that a detection mechanism such as a reflective optical sensor is effectively used in a conventional image forming apparatus.
Accordingly, an object of the present invention is to provide an image forming apparatus that can effectively use a detection mechanism.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided an image forming apparatus comprising: an apparatus main body; a cartridge detachably mounted in the apparatus main body; and the cartridge in the apparatus main body. A displacement mechanism for displacing between a first position and a second position; a moving member that is provided in the cartridge and that moves through a predetermined detection position by input of a driving force; and provided in the apparatus main body or the cartridge. And a displacement member that is displaced within a range including the detection position in accordance with the displacement of the cartridge, and detection of a state in accordance with the presence or absence of the moving member and the displacement member at the detection position. A detection mechanism that outputs a signal, and whether or not the moving member has passed through the detection position based on a state of a detection signal output from the detection mechanism; It is characterized by comprising a determining section for determining the position of the serial cartridge.

  According to a second aspect of the present invention, in the first aspect of the present invention, the image carrier is provided on the cartridge, and the cartridge is in contact with the image carrier when the cartridge is in the first position. A developer supply member for supplying a developer to the image carrier in a state of being separated from the image carrier and in contact with the image carrier when in the second position, When the cartridge is in the first position, the cartridge is moved in response to an input of a driving force, and the displacement member is disposed in the detection position when the cartridge is in the second position. .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the displacement member is provided in the cartridge, and the determination unit is in a state of a detection signal output from the detection mechanism. Based on this, it is further determined whether or not the cartridge is mounted in the apparatus main body.
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the determination unit passes the cartridge through the first position in an initial state before the start of an image forming operation. Then, the displacement mechanism is controlled to be the second position, and the position of the cartridge is determined based on a change in the state of a detection signal output from the detection mechanism during the control. .

  The invention according to claim 5 is the invention according to claim 4, wherein the detection mechanism outputs a detection signal of a first state when the moving member or the displacement member is in the detection position, and the movement When the member and the displacement member are not in the detection position, the detection signal of the second state is output, and when the state of the detection signal output from the detection mechanism changes during the control, If it is determined that the cartridge is in the second position after the control, and the state of the detection signal output from the detection mechanism during the control does not change in the second state, the cartridge is the device main body. It is characterized by determining that it is not installed inside.

The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the determination unit is based on a determination result of whether or not the moving member has passed through the detection position. It is characterized in that it is determined whether the cartridge is new or old.
The invention described in claim 7 is the invention described in any one of claims 1 to 6, wherein a plurality of the cartridges are provided, and the displacement member is provided corresponding to each cartridge. It is characterized by.

  The invention according to claim 8 is the invention according to claim 7, wherein the detection mechanism is provided for each of the displacement members, and the displacement member includes the plurality of cartridges in the first position and the second position. Are formed in different shapes so that the states of detection signals output from the respective detection mechanisms change at different timings.

  According to the first aspect of the present invention, the cartridge is provided with the moving member that moves by the input of the driving force. The moving member moves through the detection position of the detection mechanism. Further, the cartridge is displaced between the first position and the second position by the displacement mechanism. Along with the displacement of the cartridge, the displacement member is displaced within a range including the detection position of the detection mechanism. Therefore, the determination unit can determine whether the moving member has passed the detection position of the detection mechanism and the position of the cartridge based on the state of the detection signal output from the detection mechanism. Therefore, the detection mechanism can be effectively used for two determinations.

  According to the second aspect of the present invention, when the cartridge is at the first position and the developer supply member is in contact with the image carrier, it is determined whether or not the moving member has passed the detection position of the detection mechanism. Judgment can be made. On the other hand, when the cartridge is in the second position and the developer supply member is separated from the image carrier, the displacement member is disposed at the detection position of the detection mechanism. In other words, when the cartridge is in the first position and the developer supply member is in contact with the image carrier, the displacement member is not disposed at the detection position of the detection mechanism. Therefore, it is possible to determine whether or not the moving member has passed the detection position of the detection mechanism, and based on the state of the detection signal output from the detection mechanism at a time other than during the movement of the moving member, the developer It can be determined whether the supply member is in contact with or separated from the image carrier.

  According to the third aspect of the present invention, since the displacement member is provided on the cartridge, the displacement member is not disposed at the detection position of the detection mechanism unless the cartridge is mounted on the apparatus main body. Therefore, the determination unit can determine whether or not a cartridge is mounted in the apparatus main body based on the state of the detection signal output from the detection mechanism. Therefore, the detection mechanism can be effectively used for three judgments.

According to the fourth aspect of the present invention, the displacement mechanism is controlled to move the cartridge to the second position via the first position before the start of the image forming operation. The determination unit determines the position of the cartridge based on the change in the state of the detection signal output from the detection mechanism during the control.
For example, as described in claim 5, when the moving member or the displacement member is at the detection position of the detection mechanism, the detection signal of the first state is output from the detection mechanism, and the movement member and the displacement member are at the detection position of the detection mechanism. When the detection signal of the second state is output from the detection mechanism when the detection mechanism is not, the determination unit changes the state of the cartridge after the control if the state of the detection signal output from the detection mechanism changes during the control of the displacement mechanism. If the position is determined to be the second position and the state of the detection signal output from the detection mechanism during the control does not change in the second state, it is determined that the cartridge is not mounted in the apparatus main body.

According to the fourth and fifth aspects of the present invention, the control unit for controlling the image forming operation can control the image forming operation after grasping the position of the cartridge before the start of the image forming operation. . As a result, a good image forming operation can be executed, and a good quality image can be formed.
According to the sixth aspect of the present invention, the determination unit determines whether the cartridge is a new product or an old product based on the determination result of whether or not the moving member has passed the detection position. Therefore, it is possible to determine whether the cartridge is new or old and to determine the position of the cartridge by using one detection mechanism.

  According to the seventh aspect of the present invention, in the configuration in which a plurality of cartridges are provided, the displacement member is provided corresponding to each cartridge. Therefore, the position of each cartridge can be determined based on the state of the detection signal output from the detection mechanism. Therefore, for example, the image forming apparatus arranges all of the plurality of cartridges at the first position and performs the image forming operation, and a specific one of the plurality of cartridges is arranged at the first position, and the rest When the image forming operation is performed by arranging the cartridge at the second position, the position of each cartridge can be determined in each mode, and a good image forming operation can be executed.

  According to the eighth aspect of the invention, when the plurality of cartridges are simultaneously displaced between the first position and the second position, the state of the detection signal output from each detection mechanism shifts the timing. Since it changes, the type of each cartridge can be determined based on the timing of the change. Therefore, it can be determined whether or not each cartridge is properly mounted at the mounting position corresponding to the type.

1. 1 is a side sectional view of a color laser printer as an example of an image forming apparatus according to an embodiment of the present invention.
The color laser printer 1 is a tandem type color laser printer. In a main body casing 2 as an example of a box-shaped apparatus main body, a paper feeding unit 3 for feeding paper P, an image forming unit 4 for forming an image on the fed paper P, and an image And a paper discharge unit 5 for discharging the paper P on which is formed.
(1) Paper Feed Unit The paper feed unit 3 includes a paper feed tray 6 for storing the paper P in a stacked state, and a paper feed roller 7 for feeding the paper P in the paper feed tray 6 one by one. It has. The paper P sent out from the paper feed tray 6 passes through the paper transport path 8 and is transported toward the image forming unit 4.
(2) Image Forming Unit The image forming unit 4 includes a scanner unit 10, a process unit 11, a transfer unit 12, and a fixing unit 13.
(2-1) Scanner Unit The scanner unit 10 is disposed on the upper part of the main body casing 2. The scanner unit 10 includes optical members such as a laser, a mirror, and a lens, and emits four laser beams toward four photosensitive drums 14 to be described later. Each laser beam is applied to the surface of the photosensitive drum 14 as indicated by a broken line in FIG.
(2-2) Process Unit The process unit 11 is disposed below the scanner unit 10 and above the paper feed unit 3. The process section 11 includes a photosensitive drum 14 as an example of four image carriers corresponding to each color of black, yellow, magenta, and cyan. The four photosensitive drums 14 are arranged in the order of black, yellow, magenta, and cyan from the upstream side in the transport direction of the paper P, and are arranged in parallel at equal intervals in the transport direction of the paper P.

In addition, the process unit 11 includes a scorotron charger 15 and a developing cartridge 16 as an example of a cartridge in association with each photosensitive drum 14. Each developing cartridge 16 includes a housing 17 and a developing roller 18 as an example of a developer supply member supported by the housing 17.
The housing | casing 17 is formed in the box shape which has an opening in a lower end part. In the housing 17, toner as a color developer corresponding to each developing cartridge 16 is accommodated. As the toner of each color, a positively chargeable nonmagnetic one-component polymerized toner in which black, yellow, magenta and cyan colorants are blended corresponding to each color is used.

The developing roller 18 is disposed in a state in which a part of its peripheral surface is exposed from the opening at the lower end of the housing 17. The portion of the developing roller 18 exposed from the housing 17 is in pressure contact with the peripheral surface of the photosensitive drum 14 in a state where the developing cartridge 16 is disposed at a pressure contact position described later.
The developing cartridge 16 is configured to be detachable from the main casing 2. This configuration is not particularly limited, and an upper cover is provided on the upper surface of the main casing 2 so as to be freely opened and closed. When the scanner unit 10 is fixed to the upper cover and the upper cover is opened, the process unit 11 is directed upward. It may be exposed so that each developing cartridge 16 can be attached to and detached from the main casing 2 from above. Further, a front cover is provided on the front surface of the main body casing 2 (the surface on which the paper feed roller 7 is provided) so that the front cover can be opened and closed, the front cover is opened, and the process unit 11 is pulled out integrally with the front side of the main body casing 2. Each developing cartridge 16 may be detachable from the process unit 11.

  In the following description, the developing cartridge 16 to be mounted in correspondence with the black photosensitive drum 14 is referred to as “black developing cartridge 16”, and the developing cartridge 16 to be mounted in correspondence with the yellow photosensitive drum 14 is referred to as “yellow. The developing cartridge 16 that is to be mounted corresponding to the magenta photosensitive drum 14 is referred to as a “magenta developing cartridge 16”, and the developing cartridge 16 that is to be mounted to be corresponding to the black photosensitive drum 14 is referred to as a “developing cartridge 16”. This is referred to as “cyan developing cartridge 16”.

The surface of each photosensitive drum 14 is uniformly positively charged by the scorotron charger 15 as the photosensitive drum 14 rotates. Then, an electrostatic latent image corresponding to an image to be formed on the paper P is formed by irradiating the surface of the positively charged photosensitive drum 14 with a laser beam from the scanner unit 10.
When the electrostatic latent image formed on the surface of the photosensitive drum 14 faces the developing roller 18 due to the rotation of the photosensitive drum 14, the positively charged toner carried on the surface of the developing roller 18 is changed to the electrostatic latent image ( In other words, the surface of the photosensitive drum 14 that is uniformly positively charged is supplied to an exposed portion where the potential is lowered by the laser beam. As a result, the electrostatic latent image is visualized, and a corresponding color toner image is carried on the surface of the photosensitive drum 14.
(2-3) Transfer Unit The transfer unit 12 is disposed above the paper feed unit 3 and below the process unit 11 in the main body casing 2. The transfer unit 12 includes a conveyance belt 21 wound around a driving roller 19 and a driven roller 20, and four transfer rollers 22 disposed on the inner side of the conveyance belt 21 so as to face each photosensitive drum 14 and the conveyance belt 21. And.

The conveyor belt 21 is arranged so that the surface of the upper part thereof is in contact with each photosensitive drum 14. The driving roller 19 is rotated in the direction opposite to the photosensitive drum 14 (clockwise in the figure) by a driving force from a motor (not shown). When the driving roller 19 is rotated, the conveying belt 21 runs around in the same direction as the driving roller 19 and the driven roller 20 is driven to rotate.
The paper P transported from the paper feed unit 3 is supplied onto the transport belt 21 and is transported so as to sequentially pass between the photosensitive drums 14 and the transport belt 21 as the transport belt 21 rotates. During this conveyance, the toner image carried on the photosensitive drum 14 is transferred onto the paper P by the transfer bias applied to the transfer roller 22.
(2-4) Fixing Unit The fixing unit 13 includes a heating roller 23 and a pressure roller 24. The pressure roller 24 is pressed against the heating roller 23 from below.

The paper P transported by the transport belt 19 is sent between the heating roller 23 and the pressure roller 24. Then, while the sheet P passes between the heating roller 23 and the pressure roller 24, the toner image transferred to the sheet P is fixed to the sheet P by heating and pressing.
(3) Paper Discharge Unit The paper discharge unit 5 includes a paper transport path 25 and a paper discharge roller 26. The paper P conveyed from the fixing unit 13 passes through the paper conveyance path 25 and is discharged by a paper discharge roller 26 onto a paper discharge tray 27 formed on the upper surface of the main casing 2.
(4) Image Forming Mode The color laser printer 1 includes, as an image forming mode, a color mode in which a color image is formed on the paper P by superimposing black, yellow, magenta, and cyan toner images, and a black toner image. A monochrome mode for forming a monochrome image on the paper P. Each developing cartridge 16 is displaceably provided in order to achieve switching of the image forming mode and to bring the photosensitive drum 14 and the developing roller 18 into a non-contact state during non-image formation.
2. Displacement Mechanism FIGS. 2A, 2B, and 2C are side views schematically showing the configuration of the displacement mechanism.

The color laser printer 1 includes a displacement mechanism 30 for displacing each developing cartridge 16.
The displacement mechanism 30 includes an elongated substantially plate-like linear motion member 31. The linear motion member 31 faces the upper ends of the four developing cartridges 16 mounted on the main casing 2 (see FIG. 1), and the alignment direction of the photosensitive drums 14 (hereinafter, this direction is referred to as “front-rear direction”). It extends to. The linear motion member 31 is provided so as to be movable in the front-rear direction, and is reciprocated within a predetermined range in the front-rear direction by the driving force of the contact / separation motor 52 (see FIG. 3). When the contact / separation motor 52 is rotationally driven in a predetermined pressure contact direction, the driving force output from the contact / separation motor 52 at this time causes the linear motion member 31 to move toward the front side (left side in FIG. 2A). On the other hand, when the contact / separation motor 52 is rotationally driven in the separation direction opposite to the pressure contact direction, the linear motion member 31 is moved rearward (right side in FIG. 2A) by the driving force output from the contact / separation motor 52 at this time. Move towards.

Four concave portions 32 are formed on the upper surface of the linear motion member 31 at equal intervals corresponding to the developing cartridges 16. The foremost concave portion 32 is formed to have a longer length in the front-rear direction than the other three concave portions 32.
Further, the displacement mechanism 30 includes a protruding shaft 33 that extends from the side surface of the upper end portion of the housing 17 of each developing cartridge 16 toward the linear motion member 31. In a state where the developing cartridge 16 is mounted on the main body casing 2, the protruding shaft 33 is placed on the upper surface of the linear motion member 31.

As shown in FIG. 2A, in a state where the linear motion member 31 is disposed at the foremost position, the projecting shafts 33 of the four developing cartridges 16 enter the recesses 32, and all the developing cartridges 16 are at the lowermost first position. Arranged at the pressure contact position as an example, all the developing rollers 18 come into contact with all the colors in contact with the photosensitive drum 14. In the color mode, all the colors are brought into contact.
When the linear motion member 31 is moved to the rear side by a predetermined distance from the state shown in FIG. 2A, the projecting shaft 33 of the foremost black developing cartridge 16 enters the recess 32 as shown in FIG. 2B, and the yellow developing cartridge 16, the projecting shafts 33 of the magenta developing cartridge 16 and the cyan developing cartridge 16 are detached from the recess 32, and the three projecting shafts 33 are placed on the upper surface of the linear motion member 31 outside the recess 32. As a result, only the black developing cartridge 16 is disposed at the press contact position, and the yellow developing cartridge 16, the magenta developing cartridge 16, and the cyan developing cartridge 16 are moved to the separated position as an example of the uppermost second position by the linear motion member 31. It will be in a lifted state. At this time, only the developing roller 18 of the black developing cartridge 16 is in contact with the photosensitive drum 14, and the developing roller 18 of the yellow developing cartridge 16, the magenta developing cartridge 16 and the cyan developing cartridge 16 is separated from the photosensitive drum 14. Become. In the monochrome mode, this black contact state is established.

As shown in FIG. 2C, in the state where the linear motion member 31 is disposed at the last position, the projecting shafts 33 of the four developing cartridges 16 are detached from the concave portions 32 and are placed on the upper surfaces of the linear motion members 31 outside the concave portions 32. It will be in the state where it was mounted. As a result, all the developing cartridges 16 are arranged at the separated positions, and all the developing rollers 18 are separated from the photosensitive drums 14 so as to be in an all-color separated state.
3. Mechanism for various determinations (1) Mechanical configuration As shown in FIGS. 2A to 2C, a new article detection gear 40 is provided on the side surface of the housing 17 of each developing cartridge 16. The new article detection gear 40 is rotatably supported by a rotation shaft that extends from the side surface of the housing 17 in a direction orthogonal to the front-rear direction. The driving force of the developing motor 51 (see FIG. 3) is applied to the new product detection gear 40 of the new development cartridge 16 only in the first new product detection process (described later) after the new development cartridge 16 is mounted on the main casing 2. Then, the new article detection gear 40 rotates 180 degrees.

  The new article detection gear 40 of each developing cartridge 16 has the same configuration. The new article detection gear 40 is formed by integrating a disc-shaped gear body 41 as an example of a displacement member and a protrusion 42 as an example of a moving member that protrudes in the radial direction of the gear body 41 from the peripheral surface of the gear body 41. Is prepared. The protrusion 42 is provided such that the protrusion 42 is disposed on the front side with respect to the gear body 41 in a state before the new article detection gear 40 rotates in the new article detection process. When driving force is input to the new product detection gear 40 during the new product detection process, the protrusion 42 passes above the gear body 41 due to the rotation of the new product detection gear 40 and is arranged on the rear side with respect to the gear body 41. Is done.

  Further, in the main body casing 2, a new article detection switch 43 as an example of a detection mechanism is provided at a position facing the new article detection gear 40 of each developing cartridge 16 from above with each developing cartridge 16 mounted. Is provided. The new article detection switch 43 includes a switch case 44 and an advance / retreat member 45 that can advance and retreat relative to the switch case 44, and the advance / retreat member 45 is arranged to advance downward from the switch case 44. The position of the advance / retreat member 45 that has advanced most from the switch case 44 is the detection position of the new article detection switch 43.

  As shown in FIG. 2A, the new article detection gear 40 is separated downward from the new article detection switch 43 in a state where the developing cartridge 16 is disposed at the press-contact position, and the advance / retreat member 45 advances greatly from the switch case 44. At this time, the new product detection switch 43 is off, and a low level detection signal (low level signal) as an example of the second state is output from the new product detection switch 43. Further, between the new product detection gear 40 and the new product detection switch 43, the gear main body 41 does not contact the advance / retreat member 45, and the advance / retreat member 45 is on the movement path of the protrusion 42 that moves by the rotation of the new product detection gear 40. There is an interval between them.

On the other hand, as shown in FIG. 2B, the gear body 41 of the new article detection gear 40 pushes up the advance / retreat member 45 in a state where the developing cartridge 16 is disposed at the separated position, and the advance / retreat member 45 is retracted into the switch case 44. At this time, the new article detection switch 43 is turned on, and a detection signal (high level signal) in a high level state as an example of the first state is output from the new article detection switch 43.
(2) Electrical Configuration FIG. 3 is a block diagram showing an electrical configuration for various determinations.

The color laser printer 1 includes a control unit 50 as an example of a determination unit configured by a microcomputer including a CPU, a RAM, a ROM, and the like. A detection signal of the new article detection switch 43 is input to the control unit 50. Further, a developing motor 51 and a contact / separation motor 52 are connected to the control unit 50 as control targets.
The control unit 50 controls the developing motor 51 and the contact / separation motor 52, determines whether each developing cartridge 16 is new or old based on the detection signal of the new article detection switch 43, and each developing cartridge 16 Is determined (detected). Further, it is determined whether or not each developing cartridge 16 is attached to the main casing 2.
4). Initial Operation FIG. 4 is a flowchart of the initial operation.

In the color laser printer 1, the initial operation shown in FIG. In this initial operation, a position determination process (S1) for determining the position of each developer cartridge 16, a total pressure contact process (S2) for placing all the developer cartridges 16 in the pressure contact position, and each developer cartridge 16 is a new one. After a new article detection process (S3) for determining whether there is an existing product or an old product and an all separation process (S4) for arranging all the developing cartridges 16 at separation positions are performed in this order, a display unit (not shown) Then, the fact that the color laser printer 1 is waiting for the start of the image forming operation is displayed (S6).
(1) Position Determination Process FIG. 5 is a flowchart of the position determination process. 6A, 6B, 6C and 6D are side views schematically showing the states of the new article detection gear 40 and the new article detection switch 43. FIG.

In the position determination process, first, the contact / separation motor 52 is rotationally driven in the pressure contact direction (S11). As the contact / separation motor 52 rotates in the pressure contact direction, the linear motion member 31 moves toward the front side. Further, with the start of rotation driving of the contact / separation motor 52, measurement of the drive duration time of the contact / separation motor 52 is started.
Next, it is determined whether or not the drive duration time of the contact / separation motor 52 has reached a predetermined first maximum time (S12). The first maximum time is set to a time longer than the time required for the linear motion member 31 at the last position to move to the foremost position.

  If the drive duration time of the contact / separation motor 52 has not reached the first maximum time (S12: NO), it is determined whether or not low level signals are output from all the new article detection switches 43 (S13). If a high level signal is output from at least one new article detection switch 43, the determination is denied (S13: NO), and whether or not the driving duration time of the contact / separation motor 52 has reached the first maximum time. It is judged again (S12).

Before the drive duration time of the contact / separation motor 52 reaches the first maximum time, as shown in FIG. 6A, all the new article detection gears 40 are separated from the new article detection switches 43 and all the new article detection switches 43 receive a low level signal. Is output (S13: YES), the drive of the contact / separation motor 52 is stopped (S14).
On the other hand, when the driving duration time of the contact / separation motor 52 reaches the first maximum time without the low level signal being output from all the new article detection switches 43, it is determined that the driving time-out occurs (S12: YES). ), It is determined whether or not a high level signal is output from all the new article detection switches 43 (S20).

  When the high level signal is output from three or less new article detection switches 43 (S20: NO), the developing cartridge 16 corresponding to the new article detection switch 43 outputting the high level signal is disposed at the press contact position. However, it is determined that the new article detection gear 40 of the developing cartridge 16 is stopped during the new article detection process, and the protrusion 42 of the new article detection gear 40 pushes the advance / retreat member 45 of the new article detection switch 43 (S21). For example, as shown in FIG. 6B, after the new yellow developing cartridge 16 is mounted on the main casing 2, the power is turned off during the new article detecting process. Is stopped in the middle, and the protrusion 42 of the new product detection gear 40 is disposed at the detection position of the new product detection switch 43, even if the yellow development cartridge 16 is disposed at the press contact position. A high level signal is output from the new article detection switch 43 corresponding to. Therefore, in this case, based on the high level signal output from the new article detection switch 43 corresponding to the yellow developing cartridge 16, it can be determined that the new article detecting gear 40 of the yellow developing cartridge 16 is stopped during the new article detecting process. Thereafter, the driving of the contact / separation motor 52 is stopped (S14).

  On the other hand, when the high level signal is output from all the new article detection switches 43 (S20: YES), the driving of the contact / separation motor 52 is immediately stopped (S22). Then, it is determined that the protrusions 42 of the new product detection gear 40 of all the developing cartridges 16 are arranged at the detection position of the new product detection switch 43 or that some abnormality (such as a failure of the new product detection switch 43) has occurred. Then, the error is confirmed (S23), and this position determination process is ended.

When the driving of the contact / separation motor 52 in the pressure contact direction is stopped (S14), the contact / separation motor 52 is rotationally driven in the separation direction (S15). As the contact / separation motor 52 rotates in the separation direction, the linear motion member 31 moves toward the rear side. Further, with the start of rotation driving of the contact / separation motor 52, measurement of the drive duration time of the contact / separation motor 52 is started.
Next, it is determined whether or not the driving duration time of the contact / separation motor 52 has reached a predetermined second maximum time (S16). The second maximum time is set to a time longer than the time required for the linear motion member 31 in the foremost position to move to the last position, and is usually set to the same time as the first maximum time.

  If the drive duration time of the contact / separation motor 52 has not reached the second maximum time (S16: NO), it is determined whether or not a high level signal is output from all the new article detection switches 43 (S17). If a low level signal is output from at least one new article detection switch 43, the determination is denied (S17: NO), and whether or not the driving duration time of the contact / separation motor 52 has reached the second maximum time. It is judged again (S16).

  Before the driving duration time of the contact / separation motor 52 reaches the second maximum time, as shown in FIG. 6C, the advance / retreat members 45 of all the new article detection gears 40 are pushed up by the protrusions 42 of the new article detection gear 40, When a high level signal is output from the new article detection switch 43 (S17: YES), the driving of the contact / separation motor 52 is stopped (S18). Then, it is determined that the positions of all the developing cartridges 16 are separated positions (S19), and this position determination process is ended.

On the other hand, when the driving duration time of the contact / separation motor 52 reaches the second maximum time without the high level signal being output from all the new article detection switches 43, it is determined that the driving time-out occurs (S16: YES). At that time, it is determined that there is no detection target of the new article detection gear 40 outputting the low level signal, that is, the developing cartridge 16 corresponding to the new article detection gear 40 outputting the low level signal is not mounted. (S24). For example, as shown in FIG. 6D, when the yellow developing cartridge 16 is not attached to the main casing 2, a low level signal continues to be output from the new article detection switch 43 corresponding to the yellow developing cartridge 16. Accordingly, it can be determined that the yellow developing cartridge 16 is not attached. Thereafter, the driving of the contact / separation motor 52 is stopped (S18). Then, the developing cartridge 16 corresponding to the new article detection switch 43 outputting the high level signal is arranged at the separated position except for the developing cartridge 16 which is determined that the new article detecting gear 40 is stopped during the new article detecting process. (S19), the position determination process is terminated.
(2) Total pressure welding process FIG. 7 is a flowchart of the total pressure welding process.

In the full pressure contact process, first, the contact / separation motor 52 is rotationally driven in the pressure contact direction (S31). As the contact / separation motor 52 rotates in the pressure contact direction, the linear motion member 31 moves toward the front side. Further, with the start of rotation driving of the contact / separation motor 52, measurement of the drive duration time of the contact / separation motor 52 is started.
Next, it is determined whether or not the driving duration time of the contact / separation motor 52 has reached the first maximum time (S32).

  If the driving duration time of the contact / separation motor 52 has not reached the first maximum time (S32: NO), it is determined whether or not low level signals are output from all the new article detection switches 43 (S33). If a high level signal is output from at least one new article detection switch 43, the determination is denied (S33: NO), and whether or not the drive duration time of the contact / separation motor 52 has reached the first maximum time. It is judged again (S32).

Before the drive duration time of the contact / separation motor 52 reaches the first maximum time, all new article detection gears 40 are separated from the new article detection switch 43, and a low level signal is output from all the new article detection switches 43 (S33). : YES), the drive of the contact / separation motor 52 is stopped (S34).
On the other hand, when the drive duration time of the contact / separation motor 52 reaches the first maximum time without the low level signal being output from all the new article detection switches 43, it is determined that the drive has timed out (S32: YES). ), It is determined whether or not a high level signal is output from all the new article detection switches 43 (S36).

  When the high level signal is output from the three or less new article detection switches 43 (S36: NO), the developing cartridge 16 corresponding to the new article detection switch 43 outputting the high level signal is disposed at the press contact position. However, it is determined that the new article detection gear 40 of the developing cartridge 16 stops during the new article detection process, and the protrusion 42 of the new article detection gear 40 pushes up the advance / retreat member 45 of the new article detection switch 43 (S37). Then, the driving of the contact / separation motor 52 is stopped (S34).

When driving of the contact / separation motor 52 in the pressure contact direction is stopped, the developing cartridge 16 corresponding to the new article detection switch 43 outputting a low level signal determines that the new article detection gear 40 has stopped during the new article detection process. Except for the developing cartridge 16, it is determined that the cartridge is disposed at the press contact position (S35), and the entire press contact processing is completed.
On the other hand, when the high level signal is output from all the new article detection switches 43 (S36: YES), the driving of the contact / separation motor 52 is immediately stopped (S38). Then, it is determined that the protrusions 42 of the new product detection gear 40 of all the developing cartridges 16 are arranged at the detection position of the new product detection switch 43 or that some abnormality (such as a failure of the new product detection switch 43) has occurred. Then, the error is determined (S39), and this total pressure welding process is completed.
(3) New article detection process FIG. 8 is a flowchart of the new article detection process. FIG. 9 is a schematic side view showing the operation of the new product detection gear 40 and the state of the new product detection switch 43 during the new product detection process.

The new article detection process is executed in a state where the developing cartridges 16 are arranged at the press contact positions following the full press contact process shown in FIG. In the new article detection process, first, a counter provided in the RAM of the control unit 50 in association with each new article detection switch 43 is cleared (reset to zero) (S41).
Next, rotation driving of the developing motor 51 is started (S42). The driving force of the developing motor 51 is input to the new product detection gear 40 of the new development cartridge 16, and the new product detection gear 40 rotates. As the developing motor 51 starts to rotate, measurement of the driving duration time of the developing motor 51 is started.

  Thereafter, it is checked whether or not a high level signal is output from any of the new article detection switches 43 (S43). If no high level signal is output from any new article detection switch 43 (S43: NO), it is determined whether or not the driving duration of the developing motor 51 has reached a predetermined time (S44). The predetermined time is set to a time (for example, 5 seconds) longer than the time required for the new article detection gear 40 to rotate 180 degrees.

If the driving duration of the developing motor 51 has not reached the predetermined time (S44: NO), it is checked again whether a high level signal is output from any of the new article detection switches 43 (S43). That is, it is repeatedly checked whether or not a high level signal is output from any of the new article detection switches 43 until the driving duration time of the developing motor 51 reaches a predetermined time.
As shown in FIG. 9, in a state where the developing cartridge 16 is disposed at the press contact position, the new article detection gear 40 is separated downward from the new article detection switch 43, and between the new article detection gear 40 and the new article detection switch 43, The gear body 41 does not come into contact with the advance / retreat member 45, and there is an interval at which the advance / retreat member 45 is arranged on the movement path of the protrusion 42 that moves by the rotation of the new article detection gear 40. Therefore, when the new product detection gear 40 is rotated by the driving force of the developing motor 51, the protrusion 42 of the new product detection gear 40 pushes up the advance / retreat member 45 of the new product detection switch 43 during the rotation. At this time, a high level signal is output from the new article detection switch 43.

  Therefore, when a high level signal is output from the new article detection switch 43, it can be determined that the developing cartridge 16 corresponding to the new article detection switch 43 is new. Therefore, the value of the counter corresponding to the new article detection switch 43 to which the high level signal is output is set to 1 (S45). The value of the counter corresponding to the new article detection switch 43 to which no high level signal is output remains zero.

When the drive continuation time of the development motor 51 reaches a predetermined time (S44: YES), the rotation drive of the development motor 51 is stopped (S46). Thereafter, it is determined whether or not a high level signal is output from any of the new article detection switches 43 (S47).
If no high level signal is output from any new article detection switch 43 (S47: NO), it is determined whether each developing cartridge 16 is new or old based on the value of each counter (S48). ), The new article detection process ends. That is, since the new article detection switch 43 corresponding to the counter whose counter value is 1 outputs a high level signal while the new article detection gear 40 is rotating, the developing cartridge 16 corresponding to the new article detection switch 43 is new. It is determined. On the other hand, since the new article detection switch 43 corresponding to the counter whose counter value remains zero does not output a high level signal while the new article detection gear 40 is rotating, the developing cartridge 16 corresponding to the new article detection switch 43 is It is determined that the product is an old product.

If a high level signal is output from any new article detection switch 43 after the driving of the developing motor 51 is stopped, it is determined that some abnormality has occurred and an error is determined (S49). Ends.
(4) Total Separation Process FIG. 10 is a flowchart of the total separation process.

In the total separation process, first, the contact / separation motor 52 is rotationally driven in the separation direction (S51). As the contact / separation motor 52 rotates in the separation direction, the linear motion member 31 moves toward the rear side. In addition, with the start of rotation driving of the contact / separation motor 52, measurement of the drive duration time of the contact / separation motor 52 is started.
Next, it is determined whether or not the driving duration time of the contact / separation motor 52 has reached the second maximum time (S52).

  If the driving duration time of the contact / separation motor 52 has not reached the second maximum time (S52: NO), it is determined whether or not a high level signal is output from all the new article detection switches 43 (S53). If a low level signal is output from at least one new article detection switch 43, the determination is denied (S53: NO), and whether or not the driving duration time of the contact / separation motor 52 has reached the second maximum time. It is judged again (S52).

  Before the driving continuation time of the contact / separation motor 52 reaches the second maximum time, the gear main bodies 41 of all the new article detection gears 40 push up the advancing / retreating members 45 of the new article detection switches 43, and all the new article detection switches 43 receive low level signals. Is output (S53: YES), it is determined that all the developing cartridges 16 are arranged at the separated positions (S54). Then, the driving of the contact / separation motor 52 is stopped (S55), and this all separation process is completed.

On the other hand, if the drive duration time of the contact / separation motor 52 reaches the first maximum time without a high level signal being output from all the new article detection switches 43, it is determined that a drive time-out occurs (S52: YES). ). In this case, it is determined that some abnormality (such as a failure of the new article detection switch 43) has occurred, and the error is determined (S56). Then, after the driving of the contact / separation motor 52 is stopped, the entire separation process is completed.
5). Effect As described above, the developing cartridge 16 is provided with the protruding portion 42 that is moved by the input of the driving force. The protrusion 42 moves past the detection position of the new article detection switch 43. Further, the developing cartridge 16 is displaced between the press contact position and the separated position by the displacement mechanism 30. With the displacement of the developing cartridge 16, the gear body 41 of the new article detection gear 40 is displaced within a range including the detection position of the new article detection switch 43. Therefore, the control unit 50 determines whether the protrusion 42 has passed the detection position of the new product detection switch 43 and the position of the developing cartridge 16 based on the state of the detection signal output from the new product detection switch 43. Can do. Therefore, the new article detection switch 43 can be used effectively for two determinations.

  Specifically, when the developing cartridge 16 is in the pressure contact position and the developing roller 18 is in contact with the photosensitive drum 14, it is determined whether or not the protrusion 42 has passed the detection position of the new article detection switch 43. Can do. On the other hand, when the developing cartridge 16 is in the separated position and the developing roller 18 is separated from the photosensitive drum 14, the gear body 41 of the new article detection gear 40 is disposed at the detection position of the new article detection switch 43 (gear body 41). Pushes forward / backward member 45). In other words, when the developing cartridge 16 is in the pressure contact position and the developing roller 18 is in contact with the photosensitive drum 14, the gear body 41 of the new article detection gear 40 is not disposed at the detection position of the new article detection switch 43. Therefore, the state of the detection signal output from the new product detection switch 43 at a time other than during the movement of the projection 42 while it can be determined whether or not the projection 42 has passed the detection position of the new product detection switch 43. Based on the above, it can be determined whether the developing roller 18 is in contact with or separated from the photosensitive drum 14.

  Further, since the gear main body 41 of the new article detection gear 40 is provided in the developing cartridge 16, the gear main body 41 of the new article detection gear 40 is located at the detection position of the new article detection switch 43 unless the developing cartridge 16 is attached to the apparatus main body. Is never placed. Therefore, the control unit 50 can determine whether or not the developing cartridge 16 is mounted in the apparatus main body based on the state of the detection signal output from the new article detection switch 43. Therefore, the new article detection switch 43 can be used effectively for three determinations.

In the position determination process, the displacement mechanism 30 is controlled to move the developing cartridge 16 to the separation position via the pressure contact position. The control unit 50 determines the position of the developing cartridge 16 based on a change in the state of the detection signal output from the new article detection switch 43 during the control.
When the projection 42 or the gear main body 41 of the new product detection gear 40 is at the detection position of the new product detection switch 43, a detection signal in a high level state is output from the new product detection switch 43, and the gear main body of the projection 42 and the new product detection gear 40 When the detection signal of the low level state is output from the new product detection switch 43 when 41 is not at the detection position of the new product detection switch 43, the control unit 50 detects the new product during the control of the displacement mechanism 30 (during position determination processing). If the state of the detection signal output from the switch 43 changes, it is determined that the position of the developer cartridge 16 after the control is the separated position, and the state of the detection signal output from the new article detection switch 43 during the control is low. If the level remains unchanged, it is determined that the developing cartridge 16 is not mounted in the apparatus main body.

Therefore, the control unit 50 can control the image forming operation after grasping the position of the developing cartridge 16 before the start of the image forming operation. As a result, a good image forming operation can be executed, and a good quality image can be formed.
Further, in the new article detection process, it is determined whether the developing cartridge 16 is a new article or an old article based on the determination result of whether or not the protrusion 42 has passed the detection position. Accordingly, it is possible to determine whether the developing cartridge 16 is new or old and to determine the position of the developing cartridge 16 by using one new article detection switch 43.

Further, since the new article detection gear 40 is provided corresponding to each developing cartridge 16, the position of each developing cartridge 16 can be determined based on the state of the detection signal output from the new article detecting switch 43. Therefore, in each of the color mode and the monochrome mode, the position of each developing cartridge 16 can be determined and a good image forming operation can be executed.
6). Other Embodiments FIG. 11 is a schematic side view of a new article detection gear 40 according to another embodiment of the present invention. FIG. 12 is a timing chart showing a change in the state of the detection signal output from the new article detection switch 43.

In the above-described embodiment, as shown in FIG. 6A, the new article detection gears 40 provided in the developing cartridges 16 all have the same configuration. On the other hand, in this embodiment, as shown in FIG. 11, the new article detection gears 40 provided in the developing cartridges 16 have different configurations.
Specifically, the diameters of the gear bodies 41 of the new article detection gears 40 are different from each other. For example, the diameter of the gear body 41 of the new product detection gear 40 of the cyan developing cartridge 16 is the smallest, the diameter of the gear body 41 of the new product detection gear 40 of the black developing cartridge 16 is the next smallest, and the new product detection gear 40 of the yellow developing cartridge 16. The gear body 41 has the next smallest diameter, and the gear body 41 of the new article detection gear 40 of the magenta developing cartridge 16 has the largest diameter. Further, since the protrusions 42 of each new product detection gear 40 can pass through the detection position of each new product detection switch 43, each new product detection gear 40 is a long distance from the rotation center of the new product detection gear 40 to the tip of the protrusion 42. Are the same.

  As a result, when the four developing cartridges 16 are simultaneously displaced between the press contact position and the separation position, as shown in FIG. 12, the states of the detection signals output from the new article detection switches 43 are mutually synchronized. Shifts and changes. Therefore, the color order determination process described below can determine the corresponding color of each developing cartridge 16 based on the timing of the change, and whether each developing cartridge 16 is mounted at the mounting position corresponding to each color. Can be determined.

FIG. 13 is a flowchart of the color order determination process.
The color order determination process is executed by the control unit 50 (see FIG. 3) after the total separation process shown in FIG. First, the contact / separation motor 52 is rotationally driven in the pressure contact direction (S61). As the contact / separation motor 52 rotates in the pressure contact direction, the linear motion member 31 moves toward the front side. Further, with the start of rotation driving of the contact / separation motor 52, measurement of the drive duration time of the contact / separation motor 52 is started.

Next, it is determined whether or not the driving duration time of the contact / separation motor 52 has reached the first maximum time (S62).
If the drive duration time of the contact / separation motor 52 has not reached the first maximum time (S62: NO), it is determined whether or not a low level signal is output from any of the new article detection switches 43 (S63). In other words, before the start of the color order determination process, all the developing cartridges 16 are in the separated positions, and the high level signal is output from each new article detection switch 43. Therefore, the detection signal from any new article detection switch 43 is detected. It is determined whether or not has changed from the high level state to the low level state. If this determination is affirmed, the color corresponding to the new article detection switch 43 outputting the low level signal is stored in the RAM of the control unit 50 (S64). Monitoring of the state of the detection signal output from each new article detection switch 43 until a low level signal is output from all the new article detection switches 43 or the drive duration time of the contact / separation motor 52 reaches the first maximum time. Is continued. During this time, the gear body 41 of each new article detection gear 40 is sequentially separated from the advancing / retracting member 45 of each new article detection switch 43, and a low level signal is sequentially output from each new article detection switch 43 to correspond to each new article detection switch 43. The colors to be stored are sequentially stored in the RAM of the control unit 50.

When each new article detection gear 40 is formed as shown in FIG. 11, as shown in FIG. 12, from the new article detection switch 43 corresponding to each color developing cartridge 16 in the order of cyan, black, yellow and magenta, the low level is set. A signal is output.
When the low level signals are output from all the new article detection switches 43 (S65: YES), the black developing cartridge 16, the yellow developing cartridge, for example, according to the transport direction of the paper P, based on the order of the colors stored in the RAM. 16, it is determined in what order the magenta developing cartridge 16 and the cyan developing cartridge 16 are arranged (S66).

  Then, after the rotation drive of the contact / separation motor 52 is stopped (S67), the black developing cartridge 16 and the yellow developing cartridge are arranged according to whether the arrangement order of the four developing cartridges 16 is the correct color order, that is, according to the transport direction of the paper P. 16, it is determined whether the magenta developing cartridge 16 and the cyan developing cartridge 16 are arranged in this order (S68). If the arrangement order of the four developing cartridges 16 is the correct color order (S68: YES), this color order determination process is terminated. If the arrangement order of the four developing cartridges 16 is not the correct color order (S68: NO), the mounting position error (color order error) of the developing cartridge 16 is determined (S69), and this color order determining process is completed. . When the error is confirmed, a notification that the fact is displayed on a display (not shown) is given.

On the other hand, when the driving duration time of the contact / separation motor 52 reaches the first maximum time without the high level signal being output from all the new article detection switches 43, it is determined that the driving time-out occurs (S62: YES). ). In this case, the driving of the contact / separation motor 52 is immediately stopped (S70). Then, after it is determined that some abnormality (such as a failure of the new article detection switch 43) has occurred and the error is determined (S71), this color order determination process is terminated.
7). Although the configuration in which the laser beam is irradiated from the scanner unit 10 to each photosensitive drum 14 has been taken up, an LED array for exposing the photosensitive drum 14 may be provided in association with each photosensitive drum 14.

Further, the configuration in which the developing cartridge 16 is displaced in order to press and separate the developing roller 18 from the photosensitive drum 14 has been taken up, but in order to press and separate the photosensitive drum 14 from the intermediate transfer belt or the like, The present invention may be applied to a configuration in which the unit that holds the photosensitive drum 14 is displaced.
Although the tandem color laser printer 1 has been taken up, the present invention transfers the toner image for each color from each image carrier to the intermediate transfer belt, and then transfers the toner image from the intermediate transfer belt to a sheet at a time. It can also be applied to a type of color laser printer. Further, the present invention can be applied not only to a color laser printer but also to a monochrome laser printer.

FIG. 1 is a side sectional view of a color laser printer according to an embodiment of the present invention. FIG. 2A is a side view schematically showing the configuration of the displacement mechanism, and shows an all-color contact state in which all the developing cartridges are arranged at the press contact positions. FIG. 2B is a side view schematically showing the configuration of the displacement mechanism, and shows a black contact state in which the black developing cartridge is disposed at the press contact position and the other developing cartridges are disposed at the separated positions. FIG. 2C is a side view schematically showing the configuration of the displacement mechanism, and shows a state in which all the developing cartridges are separated from each other with all the developing cartridges arranged at the separated positions. FIG. 3 is a block diagram showing an electrical configuration for various determinations executed in the image forming apparatus shown in FIG. FIG. 4 is a flowchart of an initial operation in the image forming apparatus shown in FIG. FIG. 5 is a flowchart of the position determination process shown in FIG. FIG. 6A is a schematic side view of the new article detection gear and the new article detection switch shown in FIG. 1, and shows a state in which all new article detection gears are separated from the new article detection switch and all new article detection switches are off. 6B is a schematic side view of the new product detection gear and the new product detection switch shown in FIG. 1, in which the rotation of the new product detection gear of the yellow developing cartridge stops halfway, and the protrusion of the new product detection gear is the new product detection switch. This is a state in which the new product detection gears of other developing cartridges are separated from the new product detection switch. FIG. 6C is a schematic side view of the new article detection gear and the new article detection switch shown in FIG. 1, in which the gear bodies of all new article detection gears push up the advancing and retracting members of the new article detection switch, and all new article detection switches are turned off. Indicates a certain state. FIG. 6D is a schematic side view of the new product detection gear and the new product detection switch shown in FIG. 1, in which the yellow developing cartridge is not mounted, and the gear body of the new product detection gear of the other developing cartridge is the advance / retreat of the new product detection switch. The members are pushed up, and the new article detection switches are turned off. FIG. 7 is a flowchart of the total pressure contact process shown in FIG. FIG. 8 is a flowchart of the new article detection process shown in FIG. FIG. 9 is an illustrative side view showing the operation of the new article detection gear and the state of the new article detection switch during the new article detection process. FIG. 10 is a flowchart of the total separation process shown in FIG. FIG. 11 is a schematic side view of a new article detection gear according to another embodiment of the present invention. FIG. 12 is a timing chart showing the state change of the detection signal output from the new article detection switch. It is a flowchart of a color order judgment process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color laser printer 2 Main body casing 14 Photosensitive drum 16 Developing cartridge 18 Developing roller 30 Displacement mechanism 41 Gear main body 42 Protrusion part 43 New article detection switch 50 Control part

Claims (8)

The device body;
A cartridge detachably mounted in the apparatus body;
A displacement mechanism for displacing the cartridge between a first position and a second position in the apparatus main body;
A moving member that is provided in the cartridge and moves through a predetermined detection position by input of a driving force;
A displacement member provided in the apparatus main body or the cartridge, and displaced in a range including the detection position in accordance with the displacement of the cartridge;
A detection mechanism provided in the apparatus main body and outputting a detection signal in a state corresponding to the presence or absence of the moving member and the displacement member at the detection position;
The image processing apparatus includes: a determination unit configured to determine whether the moving member has passed through the detection position and a position of the cartridge based on a state of a detection signal output from the detection mechanism. Forming equipment. An image carrier;
The cartridge is provided on the cartridge and contacts the image carrier when the cartridge is in the first position, and is separated from the image carrier and contacts the image carrier when the cartridge is in the second position. A developer supply member for supplying the developer to the image carrier in a state where
The moving member receives an input of driving force when the cartridge is in the first position, and moves.
The image forming apparatus according to claim 1, wherein the displacement member is disposed at the detection position when the cartridge is in the second position. The displacement member is provided in the cartridge,
The determination unit further determines whether or not the cartridge is mounted in the apparatus main body based on a state of a detection signal output from the detection mechanism. The image forming apparatus described.   The determination unit controls the displacement mechanism to bring the cartridge to the second position via the first position in an initial state before the start of the image forming operation, and from the detection mechanism during the control. The image forming apparatus according to claim 1, wherein the position of the cartridge is determined based on a change in a state of an output detection signal. The detection mechanism outputs a detection signal of a first state when the moving member or the displacement member is at the detection position, and detects a second state when the movement member and the displacement member are not at the detection position. Output signal,
The determination unit determines that the cartridge is in the second position after the control when the state of a detection signal output from the detection mechanism changes during the control, and the detection mechanism during the control. 5. The image formation according to claim 4, wherein when the state of the detection signal output from the apparatus remains unchanged in the second state, it is determined that the cartridge is not mounted in the apparatus main body. apparatus.   The said determination part determines whether the said cartridge is a new article or an old article based on the judgment result of whether the said moving member passed the said detection position, The 1st aspect is characterized by the above-mentioned. The image forming apparatus according to claim 5. A plurality of the cartridges are provided,
The image forming apparatus according to claim 1, wherein the displacement member is provided corresponding to each of the cartridges. The detection mechanism is provided for each displacement member,
In the displacement member, when the plurality of cartridges are displaced simultaneously between the first position and the second position, the state of the detection signal output from each of the detection mechanisms changes at different timings. The image forming apparatus according to claim 7, wherein the image forming apparatuses are formed in different shapes.

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