JP2016180890A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus capable of suppressing occurrence of errors in positions of a direct-acting member when switching positions of the direct-acting member between a first position and a second position.SOLUTION: A color laser printer includes: a translation cam 400 which moves backward and forward so as to cause each developer cartridge 63K,63Y,63M,63C to move between a developing position and a non-developing position; a sensor 200 which detects a first detected part 412 and a second detected part 413; and a control section. The translation cam 400 moves among a first position for color page printing, a second position for monochrome page printing and a third position in an initial state. Each of the first detected part 412 and the second detected part 413 changes a detection state of the sensor 200 when the translation cam 400 moves to a position adjacent to the position from at least one of the first, the second, and the third position. The control section causes the translation cam 400 to move, and stops the translation cam 400 on the basis of a change in a detection state of the sensor 200.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus having a plurality of photoconductor drums arranged.

  Conventionally, a plurality of first developers containing a developer other than black, a second developer containing black developer, and a first developer and a second developer are moved in a predetermined direction. An image forming apparatus is known that includes a linear motion member that moves to a development position and a non-development position, and a sensor that detects a detected portion provided on the linear motion member (see Patent Document 1).

  The linear movement member includes a first position where all the developing units are positioned at the developing position, a second position where only the second developing unit is positioned at the developing position, and a third position where all the developing units are positioned at the non-developing position. And can be moved. The sensor detects the detected portion when the linear motion member is located at the third position.

JP 2008-58629 A

  However, in the configuration of Patent Document 1, the detection state of the sensor when the linear motion member is located at the first position and the second position does not change. Therefore, when the first position and the second position are switched, an error may occur in the position of the linear motion member.

  The present invention has been made in view of the above background, and provides an image forming apparatus capable of suppressing the occurrence of an error in the position of the linear motion member when switching between the first position and the second position of the linear motion member. The purpose is to provide.

In order to achieve the above-described object, the image forming apparatus of the present invention accommodates a developer and moves in the predetermined direction by moving the first developer and the second developer arranged in a predetermined direction. A linear motion member that moves the first developer unit and the second developer unit to a development position and a non-development position; a sensor that detects a detected portion provided in the linear motion member; and a control unit. Prepare.
The linearly moving member is adjacent to the first position where the first developing unit and the second developing unit are positioned at the developing position, and only the second developing unit is positioned at the developing position. The second position and a third position where the first developing unit and the second developing unit are positioned at the non-developing position are moved, and the detected part is configured such that the linear member is the first position, When the sensor moves from one of the second position and the third position to a position adjacent to the position, the detection state of the sensor is changed.
And the said control part moves the said linear motion member, and stops the said linear motion member based on the change of the detection state of the said sensor.

  According to such a configuration, when the linear motion member moves to a position adjacent to each other among the first position, the second position, and the third position, the detection state of the sensor changes, so the first position of the linear motion member When switching between the second position and the second position, it is possible to suppress occurrence of an error in the position of the linear motion member.

  ADVANTAGE OF THE INVENTION According to this invention, when switching the 1st position and 2nd position of a linear motion member, it can suppress that the error of the position of a linear motion member arises.

1 is a diagram illustrating a schematic configuration of a color laser printer according to an embodiment. It is a figure which shows a process unit when a linear cam is a 1st position. It is a figure which shows a process unit when a linear motion cam is a 2nd position. It is a figure which shows a process unit when a linear cam is a 3rd position. It is a figure (a) and (b) which show interlocking operation of a front cover and a direct-acting cam. It is a flowchart which shows operation | movement of initial control. It is a flowchart which shows the operation | movement of 3rd position movement control. 6 is a flowchart illustrating an operation of print control. It is a flowchart which shows the operation | movement of 2nd position movement control. It is a flowchart which shows operation | movement of 1st position movement control. It is a figure which shows a process unit when the linear cam which concerns on a modification is a 1st position.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the direction of the color laser printer 1 as an example of the image forming apparatus is as follows. The left side in FIG. 1 is “front”, the right side is “rear”, the front side of the paper is “right”, and the back side is “Left”. Also, the vertical direction in FIG.

  As shown in FIG. 1, the color laser printer 1 includes an image on a paper feed unit 3 as an example of a transport unit that transports a paper S and a supplied paper S in a main body housing 2 as an example of an apparatus main body. And an image forming unit 4 for forming the image. The image forming unit 4 mainly includes an exposure device 5, a process unit 6, a transfer unit 7, a fixing unit 8, and a linear motion cam 400 as an example of a linear motion member.

  The main body housing 2 includes a front cover 21 as an example of a cover that can open and close an opening that is opened when a developing cartridge 63 described later is attached or detached.

  The paper feed unit 3 is provided at a lower portion in the main body housing 2, and mainly includes a paper feed tray 31 that stores the paper S and a paper feed mechanism 32 that supplies the paper S from the paper feed tray 31 to the image forming unit 4. In preparation. The sheets S in the sheet feeding tray 31 are separated one by one by the sheet feeding mechanism 32 and supplied to the image forming unit 4.

  The exposure apparatus 5 is provided in the upper part in the main body housing 2 and includes a plurality of laser light sources, polygon mirrors, a plurality of lenses, a plurality of reflecting mirrors, and the like (not shown). The laser light emitted from the laser light source based on the image data is reflected by a polygon mirror or a reflecting mirror or passes through a lens to expose the surface of each photosensitive drum 61 as indicated by a chain line.

  The process unit 6 is disposed between the paper feed tray 31 and the exposure device 5, and includes a holder 100, four photosensitive drums 61 arranged in the front-rear direction (predetermined direction), and each photosensitive drum 61. Correspondingly, a charger 62 and a developing cartridge 63 provided one by one are mainly provided.

  The holder 100 is a member that holds each photosensitive drum 61 and the like, and is supported so as to be movable in the front-rear direction with respect to the main body housing 2. Thus, the holder 100 can be pulled out of the main body housing 2 by opening the front cover 21. Each developing cartridge 63 is detachably held with respect to the holder 100, and can be detached by pulling the holder 100 out of the main body housing 2.

  Each developing cartridge 63 includes a developing roller 64, a supply roller 65, a layer thickness regulating blade 66, a toner containing portion 67 for containing toner, and the like. In this embodiment, the developing cartridge 63 is arranged in this order from the front side with reference numerals 63Y, 63M, 63C, and 63K in which toners of yellow, magenta, cyan, and black are accommodated. The developing cartridges 63Y, 63M, and 63C that contain toner other than black (black) are an example of a first developing device, and the developing cartridge 63K that contains black toner is an example of a second developing device.

  The transfer unit 7 is provided between the paper feed tray 31 and the process unit 6, and includes a driving roller 71, a driven roller 72, and an endless conveyance belt 73 stretched between the driving roller 71 and the driven roller 72. Four transfer rollers 74 are mainly provided. The outer surface of the conveyance belt 73 is in contact with each photosensitive drum 61, and the transfer rollers 74 are disposed inside the conveyance belt 73 so as to sandwich the conveyance belt 73 with the respective photosensitive drums 61.

  The fixing unit 8 is provided behind the process unit 6 and the transfer unit 7, and mainly includes a heating roller 81 and a pressure roller 82 that is disposed to face the heating roller 81 and presses the heating roller 81.

  In the image forming unit 4, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed by the laser beam from the exposure device 5, so that the photosensitive drum 61 is based on the image data. An electrostatic latent image is formed. Further, the toner in the toner container 67 is supplied to the developing roller 64 via the supply roller 65 and enters between the developing roller 64 and the layer thickness regulating blade 66 so as to form a thin layer having a constant thickness. Supported on.

  Then, the toner carried on the developing roller 64 is supplied to the electrostatic latent image formed on the corresponding photosensitive drum 61, whereby the electrostatic latent image is visualized and is transferred onto the photosensitive drum 61. A toner image is formed. Thereafter, the sheet S supplied from the sheet feeding unit 3 is conveyed between the photosensitive drum 61 and the conveying belt 73 so that the toner images formed on the photosensitive drums 61 are sequentially superimposed on the sheet S. It is transferred together.

  The sheet S on which the toner image has been transferred is conveyed between the heating roller 81 and the pressure roller 82, whereby the toner image is thermally fixed. The sheet S on which the toner image is heat-fixed is discharged from the inside of the main body housing 2 by the conveying roller 23 and the discharge roller 24 provided in the main body housing 2 and placed on the paper discharge tray 22.

Next, the linear cam 400 will be described.
The linear cams 400 are arranged on both sides in the left-right direction of the process unit 6 in the main body housing 2. Note that the pair of left and right linear cams 400 are formed symmetrically with each other. In FIGS. 1 to 5, only the left side is shown, and the right side is omitted.

  The linear cam 400 is configured to be movable in the front-rear direction by being driven by a motor M as an example of a drive source provided in the main body housing 2. As shown in FIG. 2, the linear cam 400 moves in the front-rear direction so that the developing roller 64 comes into contact with the corresponding photosensitive drum 61, and the developing roller 64 is separated from the corresponding photosensitive drum 61. It is configured to move between a non-development position (for example, see FIG. 4).

  The linear cam 400 includes a cam main body 410 that is formed long in the front-rear direction, and four contact portions 420 and 430 that protrude inward from the inner surface of the cam main body 410 in the left-right direction. In other words, the four contact portions 420 and 430 protrude from the cam body 410 on the left and right direction, that is, on the left side in the drawing, toward the other side in the left and right direction, that is, on the right side in the drawing.

  The cam body 410 is supported by a rail 450 provided in the main body housing 2 so as to be movable in the front-rear direction with respect to the main body housing 2, and a rack gear 411 is formed on the upper surface of the rear end portion. . The rack gear 411 meshes with a pinion gear 260 provided in the main body housing 2. The driving force from the motor M is input to the pinion gear 260. The linear cam 400 moves rearward when the pinion gear 260 is driven to rotate counterclockwise in the figure, and moves forward when the pinion gear 260 is driven to rotate clockwise in the figure. The pair of left and right pinion gears 260 provided on the pair of left and right linear cams 400 are connected to each other via a pinion shaft 261, and the pair of left and right linear motion cams 400 move in conjunction with the rotation of each pinion gear 260. It is configured as follows.

  A first detected portion 412 and a second detected portion 413 are provided on the upper surface of the front end portion of the cam body 410. The first detected part 412 and the second detected part 413 protrude from the upper surface of the cam body 410.

  The first detected part 412 is located above the developing cartridge 63M in the front-rear direction. The second detected portion 413 is located in front of the first detected portion 412 and above the developing cartridge 63Y.

  The contact portions 420 and 430 are inclined surfaces 421 and 431 whose rear surfaces are inclined obliquely downward and forward. In addition, the rearmost abutting portion 430 has a length in the front-rear direction that is shorter than the three abutting portions 420 arranged on the front side thereof.

  Further, four swing members 140 are provided on the upper portion of the holder 100 so as to be swingable with respect to the holder 100 about the swing shaft 141. The swinging member 140 is biased by a biasing member (not shown) so as to swing in the counterclockwise direction shown in the figure, and a part of the swinging member 140 abuts against a stopper (not shown) provided on the holder 100, so that FIG. Is maintained in the posture shown in.

  Each rocking member 140 mainly includes a contacted portion 142 provided above the rocking shaft 141 and a pressing portion 143 provided below the rocking shaft 141.

  The abutted portion 142 is located at a position where it can abut against the inclined surface 421 of the abutting portion 420 of the linear motion cam 400 moving in the front-rear direction or the inclined surface 431 of the abutting portion 430. It is provided so as to protrude outward from the outer surface in the direction. Further, the pressing portion 143 extends downward from the vicinity of the swing shaft 141, and abuts against the developing pressing boss 68 projecting outward from the side surface of the developing cartridge 63 from the lower rear side.

Next, the operation of the linear motion cam 400 and the contact / separation operation of the developing roller 64 will be described.
In the following description, in order to identify the photosensitive drum 61 and the developing roller 64 corresponding to the color of the toner, Y, M, C and K are attached.

  When a color image is formed on the sheet S using toners of four colors of yellow, magenta, cyan, and black, the linear motion cam 400 is positioned at the first position shown in FIG. The image forming operation is executed in this state. At this time, the developing roller 64 and the photosensitive drum 61 are in contact with each other when the developing pressing boss 68 receives a pressing force that is inclined rearward and downward by a developing pressing member (not shown).

  On the other hand, when a monochrome image is formed on the paper S using only black toner, the linear cam 400 is moved to the second position and only the developing roller 64K is positioned at the developing position as shown in FIG. The developing rollers 64Y, 64M, and 64C are positioned at the non-developing positions.

  Specifically, when forming a monochrome image, the pinion gear 260 rotates counterclockwise from the state shown in FIG. 2 to move the linear cam 400 backward. Then, first, the inclined surfaces 421 of the three front-side contact portions 420 abut on the abutted portions 142 of the swinging members 140Y, 140M, and 140C that are part of the process unit 6. As the linear cam 400 further moves rearward, the inclined surface 421 pushes the contacted portion 142, so that the swing members 140Y, 140M, and 140C are centered on the swing shaft 141 as shown in FIG. As shown in FIG.

  As a result, the pressing portions 143 of the swinging members 140Y, 140M, and 140C push the developing pressing boss 68 of the developing cartridges 63Y, 63M, and 63C forward and obliquely upward. The developing rollers 64Y, 64M, and 64C are separated from the corresponding photosensitive drums 61Y, 61M, and 61C. Since the rearmost abutting portion 430 is shorter in the front-rear direction than the abutting portion 420, it does not interfere with the swing member 140K in the series of operations described above. As a result, the developing roller 64K is maintained in contact with the photosensitive drum 61K. A monochrome image is formed on the sheet S by executing the image forming operation in the state shown in FIG.

  In this embodiment, all the developing rollers 64 can be moved to the non-developing position in order to clean the conveyance belt 73 and the like before printing. Specifically, from the state shown in FIG. 3, the pinion gear 260 rotates in the counterclockwise direction in the drawing, thereby moving the linear cam 400 further rearward. Then, the inclined surface 431 of the abutting portion 430 abuts on the abutted portion 142 of the swinging member 140K, and the operation is performed in the same manner as described above. Located at the third position, the developing roller 64K is separated from the photosensitive drum 61K.

  In order to bring the developing roller 64K into contact with the photosensitive drum 61K from the state shown in FIG. 4, the linear cam 400 is moved forward by rotating the pinion gear 260 clockwise in the figure. Then, the engagement between the abutting portion 430 and the abutted portion 142 is released, and as shown in FIG. 3, the oscillating member 140K is centered on the oscillating shaft 141 by the urging force of the urging member (not shown). As shown in FIG. As a result, the pressing portion 143 is lowered, so that the developing cartridge 63K moves rearward and obliquely downward in conjunction with this, and the developing roller 64K comes into contact with the photosensitive drum 61K.

  Further, in order to bring the developing rollers 64Y, 64M, and 64C into contact with the corresponding photosensitive drums 61Y, 61M, and 61C from the state shown in FIG. 3, the pinion gear 260 rotates in the clockwise direction in the drawing, so that the linear motion cam 400 is rotated. Move further forward. Then, the engagement between the contact portion 420 and the contacted portion 142 is released, and the operation is performed in the same manner as described above, so that the developing rollers 64Y, 64M, and 64C correspond to the photosensitive members as shown in FIG. It contacts the drums 61Y, 64M, 64C.

  A sensor 200 is provided above the cam body 410 of the main body housing 2. The sensor 200 has a light emitting unit and a light receiving unit (not shown) that are arranged to face each other in the left-right direction. When the linear motion cam 400 moves back and forth, the sensor 200 detects the first detected unit 412 and the second detected unit 413. It is provided at a detectable position.

  When the sensor 200 detects the first detected part 412 or the second detected part 413 by positioning the first detected part 412 or the second detected part 413 between the light emitting part and the light receiving part, the ON signal Is output to the control unit 300 described later. When the first detected part 412 and the second detected part 413 are not positioned between the light emitting part and the light receiving part, the sensor 200 is turned off when the first detected part 412 or the second detected part 413 is not detected. Is output to the control unit 300.

  Here, when the linear motion cam 400 is in the first position during color image formation, the sensor 200 is located in a range where the first detected portion 412 is provided in the front-rear direction. The sensor 200 is located in a corresponding range between the first detected part 412 and the second detected part 413 in the front-rear direction when the linear cam 400 is in the second position during monochrome image formation. When the linear cam 400 is in the third position during cleaning, the sensor 200 is located in a range where the second detected portion 413 is provided in the front-rear direction.

  The first position refers to the position of the linear cam 400 when all the developing cartridges 63 are positioned at the developing position, and the second position refers to the linear movement when only the developing cartridge 63K is positioned at the developing position. The position of the cam 400 is said. The third position refers to the position of the linear cam 400 when all the developing cartridges 63 are positioned at the non-developing position. When the linear cam 400 is in the first position, the sensor 200 outputs an ON signal. When the linear cam 400 is in the second position, the sensor 200 outputs an OFF signal, and the linear cam 400 is in the third position. At this time, the first detected part 412 and the second detected part 413 are arranged so that the sensor 200 outputs an ON signal.

  When the linear motion cam 400 moves from one of the first position, the second position, and the third position to a position adjacent to the position by the first detected part 412 and the second detected part 413, The detection state of the sensor 200 is changed. Specifically, the detection state of the sensor 200 is switched from ON at the third position to OFF at the second position when the linear motion cam 400 moves from the third position to the front side and moves to the first position, for example. After that, it is switched to ON at the first position.

  Further, the first detected portion 412 described above has a longer length in the left-right direction than the second detected portion 413, and even if the linear cam 400 is moved to the foremost side, the sensor 200 is not connected to the first detected portion 412. The length is such that the detected portion 412 is located within the range provided.

  Further, as shown in FIG. 5A, the linear cam 400 is connected to the front cover 21 by a link 25. The link 25 is rotatably supported by a support portion 21 </ b> A that protrudes rearward from the vicinity of the lower end portion of the front cover 21. The link 25 has a supported portion 25A extending upward from the rear end of the support portion 21A and an extending portion 25B extending rearward from the upper end of the supported portion 25A. A long hole 25C extending in the front-rear direction is formed in the extending portion 25B.

  The cam body 410 has a protruding portion 414 that protrudes downward from the front end. A shaft 414A that protrudes in the left-right direction and engages with the long hole 25C of the extending portion 25B is provided at the lower end of the protruding portion 414. The support portion 21 </ b> A, the link 25, and the protruding portion 414 are an example of an interlocking mechanism that moves the linear cam 400 in conjunction with an operation of opening the front cover 21.

  Here, as shown in FIG. 5B, when the front cover 21 is opened, the link 25 moves to the front side while rotating with respect to the support portion 21A. By this movement, the shaft 414A is pulled to the rear edge of the long hole 25C, and the linear cam 400 moves to the front side and moves to the first position shown in FIG. For this reason, in a state where the front cover 21 is fully opened, the linear cam 400 moves to the first position regardless of the position before the front cover 21 is opened.

  On the other hand, when the front cover 21 is closed, the link 25 moves to the rear side while rotating with respect to the support portion 21A. At this time, the shaft 414A moves to the front side with respect to the long hole 25C, and in a state where the front cover 21 is completely closed, the shaft 414A is in a position where it does not contact the front edge of the long hole 25C or to the extent that it is not pushed by the front edge. Move to the position you want. For this reason, the linear cam 400 is prevented from moving from the first position by the operation of closing the front cover 21.

  As shown in FIG. 1, a motor M, a first clutch C1, a second clutch C2 as an example of a connection unit, a control unit 300, and a storage unit 310 are provided at appropriate positions of the main body housing 2. Is provided. The motor M is a motor that can rotate forward and reverse, and is configured to drive the linear cam 400 and the paper feed mechanism 32.

  The first clutch C1 is configured to be switchable between an ON state (transmission state) in which the driving force of the motor M is transmitted to the paper feed mechanism 32 and an OFF state (non-transmission state) in which the driving force is interrupted by the control unit 300. Has been.

  The second clutch C2 is switched by the control unit 300 between an ON state (transmission state) in which the driving force of the motor M is transmitted to the pinion gear 260 of the linear cam 400 and an OFF state (non-transmission state) in which the driving force is interrupted. It is configured to be possible.

  The control unit 300 includes a CPU, a ROM, a RAM, and the like, and the linear motion cam based on the change in the detection state of the sensor 200 by the CPU reading and executing the detection signal of the sensor 200 and a predetermined program. It is configured to control 400 movements.

  The control unit 300 executes movement control for moving the linear cam 400, stop control for stopping the linear cam 400, and conveyance control for conveying the paper S by the paper feed mechanism 32.

  When executing the movement control, the control unit 300 executes the control for rotating the motor M in the forward rotation or the reverse rotation. Specifically, the control unit 300 rotates the motor M forward when moving the linear cam 400 to the front side, that is, the side from the third position toward the first position. Further, the control unit 300 reversely rotates the motor M when moving the linear cam 400 to the rear side, that is, the side from the first position toward the third position.

  And the control part 300 performs the switching control which switches the 2nd clutch C2 from OFF to ON, ie, a non-transmission state to a transmission state, when the motor M is carrying out constant speed rotation. Thereby, the drive of the motor M is transmitted to the pinion gear 260, and the linear cam 400 moves.

  When executing the stop control, the control unit 300 executes control for switching the second clutch C2 from ON to OFF, that is, switching from the transmission state to the non-transmission state. As a result, the drive of the motor M is not transmitted to the pinion gear 260, and the linear cam 400 is stopped by the frictional force between the rail 450 and the linear cam 400. Note that the control unit 300 may execute stop control by stopping the rotation of the motor M.

  When executing the conveyance control, the control unit 300 performs control to rotate the motor M forward and to switch the first clutch C1 from OFF to ON. As a result, the transport rollers and the like (reference numerals omitted) in the paper feed mechanism 32 rotate, and the paper S in the paper feed tray 31 is transported. Further, the control unit 300 executes control for switching the first clutch C1 from ON to OFF when the conveyance of the sheet S is completed, when the sheet S is not conveyed, and when the motor M is reversely rotated.

  Further, the control unit 300 performs initial control for storing the position of the linear cam 400 in the initial state, first position movement control for moving the linear cam 400 to the first position, and sets the linear cam 400 to the second position. The second position movement control to be moved and the third position movement control to move the linear cam 400 to the third position are executed.

  The control unit 300 executes initial control when the color laser printer 1 is turned on and when the storage unit 310 does not store the position of the linear cam 400 when there is a print job. More specifically, the control unit 300 determines whether or not the sensor 200 is ON. If the sensor 200 is OFF, the control unit 300 determines that the linear cam 400 is located at the second position.

  When the sensor 200 is ON, the control unit 300 performs movement control for moving the linear cam 400 to the front side, and executes stop control when a predetermined time has elapsed. The predetermined time includes the detection time of the second detected portion 413 by the sensor 200 when the linear cam 400 at the third position is moved to the front side, and the first detected portion 412 and the second detected portion. What is necessary is just to set to time T1 shorter than the sum with the time which has not detected both between 413. In the present embodiment, the time T1 is shorter than the time T2 when the linear cam 400 at the first position in FIG. 2 is moved from the position to the foremost side.

  After the stop control, the control unit 300 determines whether or not the sensor 200 is ON. If the sensor 200 remains ON, the control unit 300 determines that the linear cam 400 is in the first position and switches to OFF. It is determined that the linear cam 400 is in the second position.

  When the printing control is completed, the control unit 300 performs the third position movement control when the position of the linear cam 400 is stored in the storage unit 310 as the first position or the second position. Specifically, the control unit 300 executes movement control for moving the linear cam 400 to the rear side, and executes stop control when it is determined that the linear cam 400 has reached the third position.

  The controller 300 executes the first position movement control when the linear cam 400 is located at a position other than the first position when printing a color page including other than black. In addition, when printing a black monochrome page, the control unit 300 executes the second position movement control when the linear cam 400 is located at a position other than the second position.

  When executing the first position movement control, the control unit 300 executes movement control for moving the linear cam 400 to the front side, and executes stop control when it is determined that the linear cam 400 has reached the first position.

  When executing the second position movement control, the control unit 300 executes movement control for moving the linear cam 400 to the rear side or the front side. Specifically, when the linear motion cam 400 moves from the third position, the control unit 300 performs movement control to move the linear motion cam 400 to the front side, and when the linear motion cam 400 moves from the first position, Movement control for moving the linear cam 400 to the rear side is executed. After executing the movement control, the control unit 300 executes stop control when it is determined that the linear cam 400 has reached the second position.

  Moreover, the control part 300 performs stop control based on the change of the detection state of the sensor 200 in each position movement control. More specifically, the control unit 300 determines that the linear cam 400 has moved to the position due to switching of the detection signal of the sensor 200 when the linear cam 400 has moved to an adjacent position. Then, the control unit 300 determines that the linear cam 400 has moved to the target position when switching to the detection signal at the target position, and executes stop control.

  The storage unit 310 is configured to store the position of the linear cam 400 determined by the control unit 300 in the initial control and each position movement control. In addition, the control unit 300 executes each control described above according to the position stored in the storage unit 310.

  In the present embodiment, the storage unit 310 is reset when the front cover 21 is opened or when the color laser printer 1 is turned off, and is set to a state in which the position of the linear cam 400 is not stored. It has come to be.

  Next, a detailed operation of the control unit 300 will be described. First, according to the flowchart shown in FIG. 6, the initial control in which the linear cam 400 is in the initial state will be described.

  As shown in FIG. 6, the controller 300 determines whether or not the sensor 200 is ON (S1). In step S1, the controller 300 determines that the sensor 200 is ON (S1, Yes), that is, when the sensor 200 detects the first detected part 412 or the second detected part 413, the motor M Is rotated forward (S2).

  In step S2, when the motor M rotates at a constant speed, the controller 300 turns on the second clutch C2 (S3) and moves the linear cam 400 to the front side. Thereafter, the controller 300 determines whether or not a predetermined time has elapsed (S4). When the predetermined time has not elapsed (S4, No), the control unit 300 repeats the process of step S4. When the predetermined time has elapsed (S4, Yes), the second clutch C2 is turned off and the linear cam 400 is turned off. Is stopped (S5).

  If the linear cam 400 is stopped in step S5, the controller 300 determines whether or not the sensor 200 is ON (S6). In step S6, when the control unit 300 determines that the sensor 200 is ON (S6, Yes), the control unit 300 determines that the linear cam 400 is positioned at the first position, and stores the first position in the storage unit 310 ( S7).

  When the control unit 300 determines in step S6 that the sensor 200 has been turned off (S6, No), or in step S1, the control unit 300 determines that the sensor 200 is OFF (S1, No), the linear motion cam 400. Is stored in the second position, the second position is stored in the storage unit 310 (S8), and the initial control is terminated.

Next, the third position movement control will be described with reference to the flowchart shown in FIG.
As shown in FIG. 7, the controller 300 rotates the motor M in the reverse direction (S101), and when the motor M reaches a constant speed, the second clutch C2 is turned on (S102), and the linear cam 400 is moved backward. Move to the side. After step 102, the controller 300 determines whether or not the sensor 200 is OFF (S103).

  In step 103, when the sensor 200 is ON (S103, No), that is, when the linear cam 400 is in the first position, the control unit 300 repeats the process of step 103. When the sensor 200 is OFF (S103, Yes), that is, when the linear cam 400 is located at the second position, the control unit 300 determines whether the sensor 200 is ON (S104). .

  In step S104, the control unit 300 repeats the process of step 104 when the sensor 200 remains OFF (S104, No), that is, when the linear cam 400 is at the second position. When the sensor 200 is switched ON (S104, Yes), that is, when the linear cam 400 is moved from the second position to the third position, the control unit 300 turns off the second clutch C2 (S105). The motor M is stopped (S106). Then, the control unit 300 stores the third position in the storage unit 310 (S107), and ends the third position movement control.

Next, printing control of the color laser printer 1 will be described with reference to the flowchart shown in FIG.
As shown in FIG. 8, the controller 300 determines whether a print job has been received (S11). In step S11, if the control unit 300 has not received a print job (S11, No), this control is terminated, and if a print job has been received (S11, Yes), the linear cam 400 is stored in the storage unit 310. It is determined whether the position of is unknown (S12).

  In step S12, when the position of the linear cam 400 is unknown (S12, Yes), the control unit 300 executes the initial control shown in FIG. 6 (S13). In step S12, the control unit 300 determines whether or not the position of the linear cam 400 is stored in the storage unit 310 (S12, No) or after the processing in step S13, whether or not monochrome page printing control is performed. (S14).

  In step S14, when it is monochrome page printing control (S14, Yes), it is determined whether or not the second position is stored in the storage unit 310 (S15). In step S15, when the second position is not stored in the storage unit 310 (S15, No), the control unit 300 executes second position movement control described later (S200).

  After step S200 or when the second position is stored in the storage unit 310 in step S15 (S15, Yes), the control unit 300 rotates the motor M forward (S16), and the motor M rotates at a constant speed. Then, the first clutch C1 is turned on (S17), and the paper S is transported by the paper feed mechanism 32.

  If it is not monochrome page printing control in step S14 (S14, No), that is, if printing is a color page, the control unit 300 determines whether or not the first position is stored in the storage unit 310 (step S14). S18). When the first position is stored in the storage unit 310 in step S18 (S18, Yes), the control unit 300 proceeds to the process of step S16, and is not stored in the storage unit 310 as the first position ( (S18, No), first position movement control to be described later is executed (S300), and then the process proceeds to step S16.

  When the printing of one page is completed after step S17 (S19), the controller 300 turns off the first clutch C1 (S20) and stops the motor M (S21). After step S21, the control unit 300 determines whether the print job is completed (S22). If the print job is not completed in step S22 (S22, No), the control unit 300 returns to the process of step S14, and if the print job is completed (S22, Yes), the third position shown in FIG. After executing the movement control (S100), the printing control is terminated.

Next, 2nd position movement control is demonstrated according to the flowchart shown in FIG.
As shown in FIG. 9, the control unit 300 determines whether or not the first position is stored in the storage unit 310 (S201). In step S201, the control unit 300 rotates the motor M forward when the storage unit 310 does not store the first position (S201, No), that is, when the storage unit 310 stores the third position. (S202) When the first position is stored in the storage unit 310 (S201, Yes), the motor M is reversely rotated (S203).

  After step S202 or step S203, when the motor M rotates at a constant speed, the controller 300 turns on the second clutch C2 (S204) and moves the linear cam 400. Specifically, the controller 300 moves the linear cam 400 to the front side when the motor M is rotating forward, and moves the linear cam 400 to the rear side when the motor M is rotating backward.

  After step S204, the controller 300 determines whether or not the sensor 200 has been switched off (S205). When the sensor 200 is ON in step S205 (S205, No), the control unit 300 repeats the process of step S205, and when the sensor 200 is switched OFF (S205, Yes), the second clutch C2 is turned OFF. (S206), the second position is stored in the storage unit 310 (S207), and the second position movement control is terminated.

Next, the first position movement control will be described with reference to the flowchart shown in FIG.
As shown in FIG. 10, the control unit 300 rotates the motor M forward (S301), and turns on the second clutch when the motor M rotates at a constant speed (S302). After step S302, the control unit 300 determines whether the sensor 200 is OFF (S303).

  In step S303, if the sensor 200 is not OFF (S303, No), the control unit 300 repeats the process of step S303. If the sensor 200 is OFF (S303, Yes), whether or not the sensor 200 has been turned ON. Is determined (S304).

  In step S304, when the sensor 200 is not switched on (S304, No), the control unit 300 repeats the process of step S304. When the sensor 200 is switched on (S304, Yes), the second clutch C2 is turned on. It is turned off (S305), the first position is stored in the storage unit 310 (S306), and the first position movement control is terminated.

The operation and effect of the color laser printer 1 configured as described above will be described.
When the color laser printer 1 is turned on, the control unit 300 executes initial control. Specifically, the position of the linear motion cam 400 is identified based on the detection signal of the sensor 200 after the linear motion cam 400 is moved for a predetermined time. That is, the position of the linear cam 400 is identified based on the detection time of the first detected part 412 and the second detected part 413 by the sensor 200. Then, by executing the third position movement control, the linear cam 400 is moved from the position to the third position. Accordingly, the development roller 64 can be prevented from being deformed by separating the photosensitive drum 61 and the development roller 64 until the print job is received.

  After receiving the print job, the printing control of the monochrome page or the color page is performed by moving the linear cam 400 to an appropriate position (first position or second position) by the control unit 300. Made.

  Here, in the case where printing of monochrome pages and color pages is included in one print job, for example, in the case of a configuration capable of detecting only the position of the linear cam at the third position, monochrome pages and colors When the pages are switched to each other, an error may occur in the positions of the first position and the second position. Further, in this configuration, when switching between the first position and the second position, if the switching is performed after returning to the third position, the printing speed becomes slow.

  However, in the present embodiment, the first detected part 412 and the second detected part 413 detected by the sensor 200 are adjacent to the position from any one of the first position, the second position, and the third position. Since the detection state of the sensor 200 changes when moving to a position, for example, switching from the first position to the second position can be detected. Therefore, it is possible to suppress an error in the position of the linear cam 400 when switching between the first position and the second position in the linear cam 400.

  In addition, in the case where printing of monochrome pages and color pages is included in one print job, when the first position and the second position are switched, it is possible to move directly to the target position. Switching between the position and the second position can be performed quickly.

  Further, since the control unit 300 performs the initial control when the storage unit 310 does not store the position of the linear cam 400, the position of the linear cam 400 can be easily identified.

  Further, since the linear cam 400 is moved / stopped by switching the second clutch C2, the motor M is driven with a rotational speed that is not stable as compared with the configuration in which the linear cam is directly moved / stopped by the motor. It is less likely to be affected by idling due to time or stop, and it is possible to suppress occurrence of an error in the position of the linear cam 400 when the linear cam 400 is moved / stopped.

  Further, since the second clutch C2 is switched after the motor M has rotated at a constant speed, it is possible to suppress occurrence of an error in the position of the linear cam 400 when the linear cam 400 is moved / stopped.

  Further, since the motor M is also used for the paper feed mechanism 32, the number of parts can be reduced as compared with the configuration in which the motor for the linear motion cam is provided.

  Further, since the control unit 300 executes the third position movement control when the printing control is completed, all the developing rollers 64 are in the non-developing position when printing is not performed. Therefore, the developing roller 64 can be protected as compared with the configuration in which the developing roller is always located at the developing position.

  In addition, the linear cam 400 moves to the first position in conjunction with the opening operation of the front cover 21 by the front cover 21 and the link 25. However, the initial control is executed to facilitate the position of the linear cam 400. Can be identified.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the above-described embodiment, the two detected parts 412 and 413 are provided. However, the present invention is not limited to this, and a configuration in which one detected part 417 is provided as shown in FIG. Good.

  The cam main body 410 having this configuration is formed with a first recess 415 that is recessed from the upper surface at a position corresponding to the first detected part 412 of the embodiment, and at a position corresponding to the second detected part 413 of the embodiment. A second recess 416 that is recessed from the upper surface is formed. A detected portion 417 that is a wall between the first recess 415 and the second recess 416 can be detected by the sensor 200.

  Here, the sensor 200 is positioned in a range where the first recess 415 is provided in the front-rear direction when the linear cam 400 is in the first position, and is covered in the front-back direction when the linear cam 400 is in the second position. It is located in a range where the detection unit 417 is provided. When the linear motion cam 400 is in the third position, the sensor 200 is located in a range in which the second recess 416 is provided in the front-rear direction. For this reason, the sensor 200 outputs an OFF signal when the linear cam 400 is in the first position, outputs an ON signal when the linear cam 400 is in the second position, and the linear cam 400 is in the third position. At this time, an OFF signal is output.

  Even with such a configuration, it is possible to suppress the occurrence of an error in the position of the linear cam 400 when switching between the first position and the second position in the linear cam 400, and The position of the cam 400 can be switched quickly. In this configuration, the first wall 415A on the rear side of the first recess 415 and the second wall 416A on the front side of the second recess 416 of the cam body 410 may not be provided.

  In the above-described embodiment, when the storage unit 310 does not store the position of the linear cam 400, the linear cam 400 is moved to the front side. However, the present invention is not limited to this, and may be moved to the rear side. Good.

  In the embodiment, the control unit 300 executes the third position movement control when the printing control is finished. However, the present invention is not limited to this, and the third position movement control may be executed at the start of the printing control. Good.

  In the above-described embodiment, the linear cam 400 is movable in conjunction with the operation of opening the front cover 21, but the present invention is not limited to this, and may not be interlocked with the operation of opening the front cover.

  In the above embodiment, the present invention is applied to the color laser printer 1, but the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

DESCRIPTION OF SYMBOLS 1 Color laser printer 61 Photosensitive drum 63 Developing cartridge 200 Sensor 300 Control part 310 Memory | storage part 400 Linear motion cam 412 1st to-be-detected part 413 2nd to-be-detected part M Motor

Claims (12)

A first developer unit and a second developer unit that contain the developer and are arranged in a predetermined direction;
A linear motion member that moves the first developer unit and the second developer unit to a development position and a non-development position by moving in the predetermined direction;
A sensor for detecting a detected portion provided in the linear motion member;
A control unit,
The linear motion member is
A first position where the first developing unit and the second developing unit are positioned at the developing position; a second position where only the second developing unit is positioned at the developing position and adjacent to the first position; Moving the first developing unit and the second developing unit to the third position for positioning the non-developing position;
The detected part is
When the linear motion member moves from any one of the first position, the second position, and the third position to a position adjacent to the position, the detection state of the sensor is changed,
The image forming apparatus, wherein the control unit moves the linear motion member and stops the linear motion member based on a change in a detection state of the sensor. A storage unit for storing the position of the linear motion member;
The detected portion is detected by the sensor at the first position and detected by the sensor at the third position, and the first detected portion is in the predetermined direction. A second detected part having a different length;
The control unit moves the linear motion member, and stores the position of the linear motion member in the storage unit based on a detection time when the sensor detects the first detected portion or the second detected portion. The image forming apparatus according to claim 1.   The said control part moves the said linear motion member to the one side or the other side of the said predetermined | prescribed direction, when the said memory | storage part has not memorize | stored the position of the said linear motion member. Image forming apparatus. A drive source for driving the linear motion member;
A connection portion capable of switching between a transmission state in which driving is transmitted from the driving source to the linear motion member and a non-transmission state in which driving is not transmitted to the linear motion member;
The said control part performs the switching control which rotates the said drive source and switches the said connection part to the said transmission state and the said non-transmission state, The Claim 1 characterized by the above-mentioned. The image forming apparatus described.   The image forming apparatus according to claim 4, wherein the control unit executes the switching control when the driving source is rotating at a constant speed.   The image forming apparatus according to claim 4, further comprising: a conveyance unit that conveys driving from the driving source and conveys the sheet. The first developing device contains a developer other than black,
The second developer unit stores a black developer,
The control unit moves the linear motion member to the first position when printing the color page when the print job includes a color page including non-black and a monochrome page including only black. The image forming apparatus according to claim 1, wherein when the monochrome page is printed, the linear motion member is moved to the second position.   The image forming apparatus according to claim 1, wherein the control unit moves the linearly moving member to the third position when printing control is completed. An apparatus main body having an opening in which the first developing device and the second developing device are attached and detached;
A cover supported by the apparatus main body so that the opening can be opened and closed;
The image forming apparatus according to claim 1, further comprising an interlocking mechanism that moves the linearly moving member in conjunction with an operation of opening the cover.   The image forming apparatus according to claim 9, wherein the interlocking mechanism moves the linear motion member to the first position when the cover is opened. A first developer and a second developer arranged in a predetermined direction; a first position where the first developer and the second developer are positioned at a development position; and only the second developer is located at the development position. And a second position adjacent to the first position and a third position where the first developing device and the second developing device are positioned at a non-developing position, and a linear motion member and the linear motion Provided in a member, and changes the detection state of the sensor when the linear motion member moves from any one of the first position, the second position, and the third position to a position adjacent to the position. A control method for an image forming apparatus, comprising: a sensor that detects a detection unit; and a control unit,
Control of an image forming apparatus, wherein the control unit executes movement control for moving the linear motion member and stop control for stopping the linear motion member based on a change in a detection state of the sensor. Method. A first developer and a second developer arranged in a predetermined direction; a first position where the first developer and the second developer are positioned at a development position; and only the second developer is located at the development position. And a second position adjacent to the first position and a third position where the first developing device and the second developing device are positioned at a non-developing position, and a linear motion member and the linear motion Provided in a member, and changes the detection state of the sensor when the linear motion member moves from any one of the first position, the second position, and the third position to a position adjacent to the position. A program that is applied to the control unit in an image forming apparatus that includes a sensor that detects a detection unit and a control unit.
A program for executing movement control for moving the linear motion member and stop control for stopping the linear motion member based on a change in a detection state of the sensor.

Images