JP2014238531A - Transfer device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect whether or not a transfer device is satisfactorily attached in addition to the position detection of an endless belt when forming an image.SOLUTION: A first link member 21 and a second link member 22 can be freely reciprocated in a predetermined range in approaching and separating directions to and from the side of a cam shaft 231, while being brought into press-contact with a cam 23 rotated around the cam shaft 231, displace at least one primary transfer roller in a contact/separation direction, according to the reciprocation, and are arranged on both sides across the cam shaft 231. A first detection piece 26 and a second detection piece 27 are provided in the first link member 21 and the second link member 22, respectively. After a transfer device 10 is attached to an apparatus housing, the passage of the first detection piece 26 and the second detection piece 27 reciprocated in conjunction with the reciprocation of the first link member 21 and the second link member 22 is detected by a first optical sensor 29 and a second optical sensor 30, respectively.

Description

  The present invention relates to a transfer device configured to perform primary transfer in a state where a toner image is superposed on an endless belt that is driven to circulate, and image formation that includes the transfer device and collectively transfers the synthesized image onto a recording sheet. Relates to the device.

  For example, in an electrophotographic image forming apparatus such as a copying machine or a printer capable of forming a full-color image, a plurality of photosensitive drums and latent images formed on the photosensitive drum are developed to obtain toner images of respective colors. A development unit that performs the primary transfer of the toner images of different colors formed on the respective photosensitive drums in a superimposed manner on the intermediate transfer belt, and the combined toner images are collectively transferred onto the recording medium. There is an intermediate transfer type that performs the next transfer.

  Several conventional techniques for such an intermediate transfer method will be described below.

  First, in Japanese Patent Laid-Open No. 2004-260260, the variation in the position in the lateral direction of one edge of the intermediate transfer belt is detected by two edge sensors provided along one edge of the intermediate transfer belt, and based on the detection result of the variation component. A configuration is disclosed in which the meandering correction of the intermediate transfer belt and the correction of the image signal are performed to suppress image deterioration.

  Further, in Patent Document 2, the trapezoidal detection end provided in a part of one peripheral edge of the endless belt and extending in the width direction of the endless belt faces the one peripheral edge of the endless belt. A configuration is disclosed in which a detection is performed by an optical sensor fixed to the sensor, a passage time between detection ends is measured based on a detection signal from the sensor, and an end position in the width direction of the endless belt is obtained by calculation.

  In addition, the transfer belt used in the transfer device or the image forming apparatus disclosed in Patent Document 3 includes a protrusion that protrudes from the surface of the transfer belt to detect the position of the intermediate transfer belt that rotates in the circumferential direction. The position of the intermediate transfer belt is detected by detecting the passage of the protruding portion by a type sensor.

  Further, in Patent Document 4, a light reflection type sensor or a light transmission type sensor is used to project an intermediate portion that protrudes in a direction orthogonal to the belt movement direction integrally with the intermediate transfer belt at a predetermined position on one side edge of the intermediate transfer belt. It is described that the position of the intermediate transfer belt is detected by detecting the transfer belt position detection mark.

JP 2000-259058 A JP 2009-258281 A JP 2010-224214 A JP 2011-2532 A

  Although any of the techniques proposed in Patent Documents 1 to 4 can detect position information such as a circumferential position or a width position of the intermediate transfer belt, the intermediate transfer using the intermediate transfer belt is used. It is impossible to detect a mounting state such as a device not mounted or a mounting failure.

  The present invention has been made in view of such circumstances, and provides a transfer device capable of detecting whether or not the transfer device is mounted in addition to detecting the position of the endless belt during image formation, and an image forming apparatus including the transfer device. The purpose is to do.

  The transfer device of the present invention is detachably attached to the housing of the image forming apparatus. The transfer device includes an endless belt, a transfer roller, a first link member and a second link member, a first detection piece and a second detection piece, and a tension applying member.

  The endless belt is driven to rotate in the circumferential direction by the driving force transmitted from the driving member disposed inside the belt loop to the inner circumferential surface of the belt loop.

  The transfer roller is disposed on the opposite side of the plurality of photosensitive drums with respect to the endless belt, and is freely displaceable in the direction of contact with the plurality of photosensitive members.

  The first link member and the second link member are allowed to reciprocate within a predetermined range in the approaching direction and the separating direction toward the camshaft while being pressed against a cam rotating about the camshaft, and accompanying the reciprocation. At least one transfer roller is displaced in the contact / separation direction, and is disposed on both sides with the cam shaft interposed therebetween.

  The first detection piece and the second detection piece are respectively provided on the first link member and the second link member, face one of the peripheral portions of the endless belt, and protrude outward from the width direction of the endless belt. The protrusion amounts of the first detection piece and the second detection piece may be the same or different.

  The tension applying member is disposed inside the belt loop of the endless belt, and acts on the inner peripheral surface of the endless belt to apply tension to the endless belt.

  The transfer apparatus configured as described above is configured to be detachable from the apparatus housing.

  According to this transfer device, the first detection member and the second detection member are provided on the first link member and the second link member, respectively, so that the first link member and the second link member are mounted after the transfer device is mounted on the apparatus housing. By detecting the passage of the first detection piece and the second detection piece that reciprocate in conjunction with the reciprocation of the link member by the first detection means and the second detection means, respectively, it is possible to detect the position of the endless belt during image formation. In addition, it is possible to detect whether or not the transfer device is mounted.

  When the protrusion amounts of the first detection piece and the second detection piece projecting outward from the endless belt are different, the detection positions of the first detection means and the second detection means are the same, and the first detection piece and the second detection piece When the protruding amount of the endless belt protruding to the outside is the same, it is possible to detect whether the transfer device is mounted with high accuracy by making the detection positions of the first detection means and the second detection means different. .

  As the detection means, either a contact type or a non-contact type sensor may be employed.

  When used in an image forming apparatus in combination with a contact-type sensor, in addition to the detection means being arranged outside the end in the width direction of the endless belt, there is almost no effect even if toner adheres to the detection means. Since it is not received and erroneous detection / malfunction does not occur, the position detection accuracy of the endless belt can be improved.

  Even when used in an image forming device in combination with a non-contact type sensor, the detection means is placed outside the end in the width direction of the endless belt, making it less susceptible to toner adhesion and causing false detection / malfunction. Therefore, the position detection accuracy of the endless belt can be improved.

  The image forming apparatus of the present invention includes the transfer device, the photosensitive drum, the latent image forming unit, the developing unit, the first detection piece, and the second detection piece configured as described above.

  Accordingly, in addition to detecting the position of the endless belt, it is possible to provide an image forming apparatus that detects the unattached state of the transfer device to the apparatus housing and whether the attachment is good or not with high accuracy.

  Then, based on the detection results of the first detection means and the second detection means, when an unattached state or poor attachment of the transfer device is detected, a message prompting the attachment or correction of the transfer device is displayed on the display means.

  The transfer device is properly mounted or the mounting state is corrected by the user who has received the message notification, so that the position shift of the transfer device over time, incomplete positioning of other transfer devices (secondary transfer devices), It is possible to prevent the occurrence of unnecessary troubles / problems directly related to image quality problems such as poor contact of the back surface electrodes of the transfer device.

  According to the present invention, the position of the endless belt can be detected by using the existing sensor for detecting the position of the endless belt provided for printing position alignment and the configuration of the detected portion, and by making a partial change or improvement. In addition, it is possible to detect a mounting state such as a transfer device not mounted or a mounting failure with high accuracy.

FIG. 1A is a schematic cross-sectional view illustrating a standby mode of an intermediate transfer apparatus that is a main part of an image forming apparatus according to the present invention. FIG. 1B is a schematic sectional view showing a monochrome mode of the intermediate transfer apparatus. FIG. 1C is a schematic cross-sectional side view showing a full color mode of the intermediate transfer apparatus. FIG. 2 is a schematic configuration plan view showing the intermediate transfer device as seen through the intermediate transfer belt. FIG. 3 is an explanatory diagram for explaining the movement of the swinging member and the transfer roller that are linked to the link member that moves as the position of the intermediate transfer belt changes. 3A shows a state in which the primary transfer roller is positioned at a pressing position where the intermediate transfer belt is pressed against the photosensitive drum, and FIG. 3B shows a separation position where the intermediate transfer belt is separated from the photosensitive drum. Shows a state in which the primary transfer roller is moved. It is explanatory drawing explaining a motion of the link member which reciprocates with rotation of a cam. 4A shows the standby mode, FIG. 4B shows the monochrome mode, and FIG. 4C shows the full color mode. FIG. 5A is an explanatory diagram illustrating the configuration of the swing mechanism of the arm that supports the tension roller. FIG. 5B is an explanatory view illustrating the configuration of the swing mechanism of the arm that supports the tension roller. FIG. 10 is a plan view for explaining an example of a mounting state of the intermediate transfer device when the protrusion amounts of the first detection piece and the second detection piece are different and the detection positions of the first optical sensor and the second optical sensor are the same. FIG. 10 is a plan view for explaining another example of the mounting state of the intermediate transfer device when the protrusion amounts of the first detection piece and the second detection piece are different and the detection positions of the first optical sensor and the second optical sensor are the same. . Schematic diagram for explaining an example of the transmission or light shielding state of the detection beam of the optical sensor when the protrusion amounts of the first detection piece and the second detection piece are different and the detection positions of the first optical sensor and the second optical sensor are the same. It is. 8A shows a state in which the intermediate transfer device is not attached, FIG. 8B shows a state in which the intermediate transfer device is well attached, and FIG. 8C shows a state in which the intermediate transfer device is poorly attached. Another example of the transmission or light shielding state of the detection beam of the optical sensor when the protrusion amounts of the first detection piece and the second detection piece are different and the detection positions of the first optical sensor and the second optical sensor are the same will be described. It is a schematic diagram. FIG. 9A shows a state where the intermediate transfer device is not attached, FIG. 9B shows a state where the intermediate transfer device is well attached, and FIG. 9C shows a state where the intermediate transfer device is poorly attached. FIG. 6 is a diagram illustrating an example of a method for determining a belt position in an unmounted state of the intermediate transfer device, a standby mode, a monochrome mode, and a full color mode based on a detection result of an optical sensor. When the first detection piece and the second detection piece have different protrusion amounts and the detection positions of the first optical sensor and the second optical sensor are the same, the optical sensor determines whether the intermediate transfer device is not attached or is attached. It is a figure which shows an example of the method of judging based on the detection result. When the first detection piece and the second detection piece have different protrusion amounts and the detection positions of the first optical sensor and the second optical sensor are the same, the optical sensor is used to determine whether the intermediate transfer device is not attached or is attached. It is a figure which shows the other example of the method of judging based on the detection result of. It is a top view explaining the mounting state of an intermediate transfer device when the amount of protrusion of the 1st detection piece and the 2nd detection piece is the same, and the detection position of the 1st optical sensor and the 2nd optical sensor is the same. Schematic for explaining an example of the transmission or light shielding state of the detection beam of the optical sensor when the first detection piece and the second detection piece have the same protruding amount and the detection positions of the first optical sensor and the second optical sensor are the same. FIG. FIG. 14A shows a state where the intermediate transfer device is not attached, FIG. 14B shows a state where the intermediate transfer device is well attached, and FIG. 14C shows a state where the intermediate transfer device is poorly attached. Another example of the transmission or light shielding state of the detection beam of the optical sensor when the protrusion amount of the first detection piece and the second detection piece is the same and the detection positions of the first optical sensor and the second optical sensor are the same will be described. It is a schematic diagram to do. FIG. 14A shows a state where the intermediate transfer device is not attached, FIG. 14B shows a state where the intermediate transfer device is well attached, and FIG. 14C shows a state where the intermediate transfer device is poorly attached. FIG. 10 is a plan view for explaining an example of a mounting state of the intermediate transfer device when the protrusion amounts of the first detection piece and the second detection piece are the same and the detection positions of the first optical sensor and the second optical sensor are different. FIG. 6 is a plan view for explaining another example of the mounting state of the intermediate transfer device when the protrusion amounts of the first detection piece and the second detection piece are the same and the detection positions of the first optical sensor and the second optical sensor are different. is there. 1 is a block diagram illustrating a schematic configuration of an image forming apparatus of the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  The configuration of the intermediate transfer apparatus 10 according to the first embodiment of the present invention will be described. Since other configurations constituting the image forming apparatus are known, illustration and description are omitted.

  As shown in FIGS. 1A to 1C, the intermediate transfer belt 41 is stretched between a first stretching roller 42 and a second stretching roller 43 to move in a predetermined loop shape. Configure the route. In the moving direction 93 of the intermediate transfer belt 41 in the region facing the photoconductor drums 31A to 31D along the outer peripheral surface of the intermediate transfer belt 41, the photoconductor drum 31D, the photoconductor drum 31C, and the photoconductor drum in order from the upstream side. 31B and a photosensitive drum 31A are arranged.

  In the moving direction 93, the first stretching roller 42 is disposed on the downstream side, and the second stretching roller 43 is disposed on the upstream side. As described above, the primary transfer rollers 34A to 34D are arranged at positions facing the photosensitive drums 31A to 31D with the intermediate transfer belt 41 interposed therebetween. In this embodiment, the intermediate transfer belt 41 is disposed above the photosensitive drums 31A to 31D.

  As shown in FIG. 5A, the tension roller 44 is in pressure contact with the inner peripheral surface of the intermediate transfer belt 41. The tension roller 44 is rotatably supported at the tip of the arm 441. The base end portion of the arm 441 is rotatably supported by a frame (not shown) of the intermediate transfer device 10. The arm 441 is biased by a spring 442 in a direction in which the tension roller 44 is pressed against the inner peripheral surface of the intermediate transfer belt 41. Thus, the intermediate transfer belt 41 is held at a constant tension through the standby mode, the monochrome mode, and the full color mode.

  The primary transfer rollers 34 </ b> A to 34 </ b> D are configured to be displaceable in the direction of separating from and contacting the photosensitive drums 31 </ b> A to 31 </ b> D that face each other. Accordingly, the primary transfer roller 34A is displaceable at least between a pressing position where the intermediate transfer belt 41 is pressed against the opposing photosensitive drum 31A and a separation position where the intermediate transfer belt 41 is separated from the opposing photosensitive drum 31A. It is. The primary transfer rollers 34B to 34D are the same as the primary transfer roller 34A.

  As shown in FIG. 1A, in the standby mode, all of the primary transfer rollers 34A to 34D are arranged at the respective separation positions, and the intermediate transfer belt 41 is separated from the photosensitive drums 31A to 31D.

  As shown in FIG. 1B, in the monochrome mode, the monochrome primary transfer roller 34A is disposed at the pressing position and presses the intermediate transfer belt 41 against the photosensitive drum 31A. On the other hand, the primary transfer rollers 34B to 34D for color are arranged at the respective separation positions, and separate the intermediate transfer belt 41 from the photosensitive drums 31B to 31D.

  As shown in FIG. 1C, in the full color mode, all the primary transfer rollers 34A to 34D are disposed at the respective pressing positions, and press the intermediate transfer belt 41 against the photosensitive drums 31A to 31D.

  The primary transfer rollers 34 </ b> A to 34 </ b> D are displaced by the transfer member moving mechanism 20 in the separation / contact direction.

  The transfer member moving mechanism 20 includes a first link member 21, a second link member 22, a cam 23, and first to fourth swing members 24A, 24B, 24C, and 24D.

  A cam 23 is disposed between the first link member 21 and the second link member 22 along the moving direction 93 of the intermediate transfer belt 41. The first link member 21 and the second link member 22 are arranged so that the longitudinal direction thereof is parallel to the movement direction 93, and are movable within a predetermined range along the movement direction 93. The first link member 21 and the second link member 22 are urged toward the cam 23 and are in pressure contact with the cam 23.

  As shown in FIG. 2, the first link member 21, the second link member 22, and the cam 23 are between the first stretching roller 42 and the second stretching roller 43, and are not shown in the image forming apparatus. It is arrange | positioned at each of the front side and the back side. The primary transfer roller 34A is pivotally supported by the first link member 21 disposed on the front side and the first link member 21 disposed on the back side. The primary transfer rollers 34 </ b> B to 34 </ b> D are respectively pivotally supported by the second link member 22 disposed on the front side and the second link member 22 disposed on the back side.

  The front-side cam 23 and the rear-side cam 23 are fixed to a single cam shaft 231 and rotate with the same phase around the cam shaft 231. The cam shaft 231 rotates when power is transmitted from the drive source 232. For example, a stepping motor is used as the drive source 232.

  As shown in FIGS. 3A and 3B, the first to fourth swinging members 24A to 24D each have a shape bent in an L shape. The second to fourth swing members 24B to 24D are configured in the same manner as the first swing member 24A except for the mounting direction with respect to the second link member 22 in the moving direction 93. The second to fourth swing members 24B to 24D are attached to the first swing member 24A symmetrically in FIG.

  The first end 241A of the first swing member 24A is rotatably supported by a frame (not shown) of the intermediate transfer device 10 on the photosensitive drum 31A side with respect to the first link member 21. The second end 242A of the first swing member 24A supports the primary transfer roller 34A in a rotatable manner. Similarly, the first ends of the second to fourth swing members 24B to 24D are rotatable to a frame (not shown) of the intermediate transfer device 10 on the photosensitive drums 31B to 31D side with respect to the second link member 22. It is supported by. The second ends of the second to fourth swinging members 24B to 24D respectively support the primary transfer rollers 34B to 34D so as to be rotatable.

  As shown in FIG. 5B, the first swing member 24A is urged in a direction away from the photosensitive drum 31A by a spring 244A. Similarly, the second to fourth swinging members 24B to 24D are urged by springs in directions away from the photosensitive drums 31B to 31D. In FIG. 3A and FIG. 3B, the description of the spring 244A is omitted.

  The first link member 21 has a slit 25 that is long in a direction orthogonal to the moving direction 93 at a position corresponding to the primary transfer roller 34A. The second link member 22 has a long slit in a direction orthogonal to the moving direction 93 at a position corresponding to each of the primary transfer rollers 34B to 24D.

  The first swing member 24A has a protrusion 243A that protrudes in the direction of the rotation axis of the primary transfer roller 34A at the bent portion. The protrusion 243 </ b> A is displaced along the longitudinal direction of the slit 25 in the slit 25 of the first link member 21. The protrusions of the second to fourth swing members 24B to 24D are displaced in the respective slits of the second link member 22 along the longitudinal direction of the respective slits.

  Therefore, as shown in FIG. 3B, when the first link member 21 moves downstream in the direction away from the cam shaft 231, that is, in the moving direction 93 of the intermediate transfer belt 41, it resists the elastic force of the spring 244 A. The protrusion 243A descends in the slit 25, and the primary transfer roller 34A descends and is displaced to the pressing position. As a result, the intermediate transfer belt 41 is pressed against the photosensitive drum 31A.

  On the other hand, as shown in FIG. 3A, when the first link member 21 moves upstream in the direction approaching the cam shaft 231, that is, in the moving direction 93, the protrusion 243 </ b> A moves in the slit 25 by the elastic force of the spring 244 </ b> A. Ascending, the primary transfer roller 34A rises and is displaced to the separation position. As a result, the intermediate transfer belt 41 is separated from the photosensitive drum 31A.

  Similarly, when the second link member 22 moves to the upstream side in the direction away from the cam shaft 231, that is, the moving direction 93, the primary transfer rollers 34 </ b> B to 34 </ b> D move down to the respective pressing positions, and the second link member When 22 moves to the downstream side in the direction approaching the camshaft 231, that is, the moving direction 93, it moves upward and moves to each separated position.

  As shown in FIGS. 4A to 4C, the cam 23 includes a first cam portion 233 and a second cam portion 234. The first cam portion 233 and the second cam portion 234 are fixed to the cam shaft 231 at a position shifted along the cam shaft 231 and rotate around the cam shaft 231. The first link member 21 is in pressure contact with the working peripheral surface of the first cam portion 233. The second link member 22 is in pressure contact with the working peripheral surface of the second cam portion 234. The 1st cam part 233 and the 2nd cam part 234 are each comprised by the eccentric cam.

  As shown in FIG. 4A, in the standby mode, the cam 23 is disposed at a predetermined first angle. As a result, both the first link member 21 and the second link member 22 approach the cam shaft 231. For this reason, all the primary transfer rollers 34A to 34D are arranged at the separation positions, and the intermediate transfer belt 41 is separated from all the photosensitive drums 31A to 31D.

  As shown in FIG. 4B, in the monochrome mode, the cam 23 is arranged at a predetermined second angle rotated 90 degrees counterclockwise in FIG. 4B with respect to the state of the standby mode, that is, the first angle. Is done. As a result, the first link member 21 is separated from the cam shaft 231, and the second link member 22 approaches the cam shaft 231. Therefore, the monochrome primary transfer roller 34A is displaced to the pressing position, and the intermediate transfer belt 41 is pressed against the photosensitive drum 31A. On the other hand, the primary transfer rollers 34B to 34D for color are arranged at spaced positions, and the intermediate transfer belt 41 is separated from the photosensitive drums 31A to 31D for color.

  As shown in FIG. 4C, in the full color mode, the cam 23 is arranged at a predetermined third angle rotated 180 degrees counterclockwise in FIG. 4C with reference to the state of the standby mode, that is, the first angle. Is done. As a result, both the first link member 21 and the second link member 22 are separated from the cam shaft 231. For this reason, all the primary transfer rollers 34A to 34D are arranged at the pressing positions, and the intermediate transfer belt 41 is pressed against all the photosensitive drums 31A to 31D.

  As described above, the first link member 21 and the second link member 22 move corresponding to each mode, and the position of the intermediate transfer belt 41 is changed.

  Next, a mechanism for detecting whether or not the intermediate transfer device 10 is attached to the apparatus housing according to the present invention will be described.

  As shown in FIG. 6, the intermediate transfer device 10 configured as described above is detachable from the front side frame 51 and the rear side frame 52 that are firmly installed in the apparatus housing of the image forming apparatus. It is attached to. For fixing the transfer device 10, the front frame 51 is tightened to the front side with fixing screws at several locations. The intermediate transfer device 10 is attached so that the axial direction of the first stretching roller 42 and the second stretching roller 43 is perpendicular to the front frame 51 and the rear frame 52 and is substantially horizontally oriented. It is done. At this time, the first link member 21 and the second link member 22 are oriented parallel to the front side frame 51 and the back side frame 52.

  As shown in FIG. 2, a first detection piece 26 and a second detection piece 27 are respectively provided on the first link member 21 and the second link member 22 on the back side. The first detection piece 26 and the second detection piece 27 face the peripheral portion on the back side of the intermediate transfer belt 41 and protrude outward from the widthwise end of the intermediate transfer belt 41. The first detection piece 26 and the second detection piece 27 may be attached to the link member on the front side.

  As shown in FIG. 6 or FIG. 7, the first detection piece 26 and the second detection piece 27 have different protrusion amounts (reference numerals L1 and L2 respectively) protruding outside the intermediate transfer belt 41. The protrusion amount of the first detection piece 26 is opposite when the protrusion amount of the first detection piece 26 is larger than the protrusion amount of the second detection piece 27 (L1> L2, see FIG. 6). May be smaller than the protruding amount of the second detection piece 27 (L1 <L2, see FIG. 7).

  Corresponding to the first detection piece 26 and the second detection piece 27, the first optical sensor 29 and the second optical sensor 30 are respectively installed on the housing side of the image forming apparatus. The first optical sensor 29 and the second optical sensor 30 are examples of the detection means of the present invention. The detection means is not limited to a non-contact type sensor such as an optical sensor, and a contact type sensor (for example, an actuator or the like) may be employed.

  The first optical sensor 29 and the second optical sensor 30 are for detecting the positions of the first detection piece 26 and the second detection piece 27. The positions of the first detection piece 26 and the second detection piece 27 are positions in the reciprocating direction of the first link member 21 and the second link member 22. For this reason, as shown in FIGS. 8 and 9, each of the optical sensors 29 and 30 includes light emitting units 291 and 301 and light receiving units 292 and 302 that are spaced apart in the vertical direction. In this arrangement, a beam-like light beam such as a laser beam is emitted vertically downward from the light emitting units 291 and 301, and this light beam is received by the light receiving units 292 and 302. The optical sensors 29 and 30 are turned on when the light beam is not blocked between the light emitting units 291 and 301 and the light receiving units 292 and 302, and turned off when the light beam is blocked by the detection piece.

  In the present embodiment, the sensor detection positions of the first optical sensor 29 and the second optical sensor 30 are defined as the distances from the back frame 52 to the detection beams of the sensors (represented by reference numerals D1 and D2, respectively). The reason is that the rear frame 52 is used as a reference, but the front frame 51 may be used as a reference. In the present embodiment, the sensor detection positions of the first optical sensor 29 and the second optical sensor 30 are set to be the same (D1 = D2).

  According to this embodiment, even if the detection positions of the optical sensors 29 and 30 are the same, the protruding amounts of the detection pieces 26 and 27 are different, so that the penetration amounts of the detection pieces 26 and 27 into the optical sensors 29 and 30 are different. .

  Each detection piece 26, 27 can pass between each light emitting part 291, 301 and each light receiving part 292, 302 as the link members 21, 22 reciprocate. Since the positions of the detecting members 26 and 27 in the reciprocating direction of the link members 21 and 22 are different in the standby mode, the monochrome mode, and the full color mode, the ON / OFF combination of the optical sensors 29 and 30 is different. Can detect the belt position.

  An example is shown in FIG. When the intermediate transfer device 10 is not attached, both the first optical sensor 29 and the second optical sensor 30 are turned on. When the intermediate transfer device 10 is properly mounted, the first optical sensor 29 is turned off and the second optical sensor 30 is turned on in the full color mode. In the monochrome mode, the first optical sensor 29 is turned on and the second optical sensor 30 is turned off. In the standby mode, both the first optical sensor 29 and the second optical sensor 30 are turned off.

  The protrusion amount (L1) of the first detection piece 26 and the protrusion amount (L2) of the second detection piece 27 are different. Based on the difference in protrusion amount between the detection pieces 26 and 27, it is possible to detect whether the intermediate transfer device 10 is attached or not using the first optical sensor 29 and the second optical sensor 30.

  Here, the poor mounting of the intermediate transfer device 10 means that the intermediate transfer device 10 floats to the front side with respect to the mounting direction due to forgetting tightening of the fixing screw or insufficient tightening. The intermediate transfer device 10 is well mounted because the fixing screw is not forgotten to be tightened and is sufficiently tightened, and the intermediate transfer device 10 is fixed at an appropriate position without floating to the front side in the mounting direction. is there.

  Next, a schematic configuration of the image forming apparatus 1 including the intermediate transfer device 10 configured as described above will be described based on a block diagram shown in FIG.

  As shown in FIG. 18, the image forming apparatus includes a CPU 11, a ROM 12 that stores a control program executed by the CPU 11 and other data, a RAM 13 that is a work memory for developing image data to be processed, an execution program, and the like, and an Ethernet. (Registered trademark), an interface unit 14 that exchanges data with an external device via a telephone line, wireless, and the like, a writing unit (LSU) 15, a developing unit 16, and driving of the intermediate transfer belt 41 are controlled. The belt position detector 18 that detects the belt position of the intermediate transfer belt 41 based on the detection signals of the intermediate transfer belt driving unit 17, the first optical sensor 29 and the second optical sensor 30, the first optical sensor 29 and the second optical sensor 29. Based on the detection result of the optical sensor 30, when the intermediate transfer device 10 is not mounted or is not mounted correctly The main scanning position of writing by the writing means (LSU) 15 is displayed based on the display means 19 for displaying a message for prompting the mounting or correction of the intermediate transfer device 10 and the position of the intermediate transfer belt 41 detected by the belt position detecting section 18. Main scanning position control means 31 for controlling, and sub-scanning position control means 32 for controlling the sub-scanning position of writing by the writing means (LSU) 15 based on the position of the intermediate transfer belt 41 detected by the belt position detector 18. Each of which is connected via an internal bus.

  When multiple color images are transferred to the intermediate transfer belt 41 to form a color image, if the tension of the intermediate transfer belt 41 is affected by fluctuations in the tension or meandering, the superimposed images will be displaced and image quality will be deteriorated. In order to prevent image quality deterioration, simultaneously with the control of the image forming timing of the main scanning of the writing means 15 based on the amount of belt position fluctuation (meandering, offset) orthogonal to the running direction of the intermediate transfer belt 41 at the image transfer position, The sub-scanning image forming position is controlled in accordance with the time difference between the belt position detection signal and the synchronization detection signal of the writing means 15.

  In the present invention, after the intermediate transfer device 10 is mounted, the position of the intermediate transfer belt 41 is positively changed, and the first detection piece 26 and the second detection piece that reciprocate together with the first link member 21 and the second link member 22. 27 can be detected by the first optical sensor 29 and the second optical sensor 30 to detect whether the wearing state is good or bad. For this purpose, the protrusion amount difference between the detection pieces 26 and 27 described above is used.

  As shown in FIG. 13, the detection positions of the first optical sensor 29 and the second optical sensor 30 are equal (D1 = D2). In this embodiment, if the first detection piece 26 and the second detection piece 27 are different in projection amount. If there is no equality (L1 = L2), it is impossible to accurately detect the quality of the wearing state.

  In other words, as shown in FIG. 14, if the protruding amounts of the detection pieces 26 and 27 are equal and both are set to a sufficient size, even if the intermediate transfer device 10 floats to the front side, both detection pieces are detected. 26 and 27 reach the detection positions of the corresponding optical sensors 29 and 30, respectively. For this reason, a mounting failure of the intermediate transfer apparatus 10 is erroneously detected as a good mounting. On the contrary, as shown in FIG. 15, when the protruding amounts of the detection pieces 26 and 27 are equal and both are too small, when the intermediate transfer device 10 floats to the front side, both the detection pieces 26 and 27 have their leading ends. It does not reach the detection position of the corresponding optical sensor 29, 30. For this reason, mounting of the intermediate transfer device 10 is erroneously detected as not mounted.

  On the other hand, in this embodiment, the protrusion amount of the 1st detection piece 26 and the 2nd detection piece 27 differs. For this reason, when the mounting failure of the intermediate transfer device 10 occurs, the entire intermediate transfer device 10 is floated to the front side of the device, and therefore, as shown in FIG. 8 or FIG. The tip portion reaches the detection position of the corresponding optical sensor, but the tip portion of the detection piece with the smaller protrusion amount does not reach the detection position of the corresponding optical sensor. As a result, the detection piece on the sensor side with a small protrusion amount is detached from the detection beam.

  In this state, when the link members 21 and 22 move in accordance with the position change of the intermediate transfer belt 41, the optical sensor corresponding to the detection piece having the larger protrusion amount as shown in FIG. Although the ON / OFF switching occurs continuously with the passage, the optical sensor corresponding to the detection piece with the smaller protrusion amount is always ON (translucent state). Defective mounting is detected.

  According to the present embodiment, the configuration for executing the position change of the intermediate transfer belt 41 related to image formation is used, and the detection pieces 26, 22 are moved together with the movement of the link members 21, 22 accompanying the position change of the intermediate transfer belt 41. By moving 27, it is possible to detect a mounting failure of the intermediate transfer device 10. If the intermediate transfer device 10 is not attached or is not attached properly, it is displayed on the display means 19 such as an operation panel to warn the user and prompt the user to attach or correct it.

  Next, a second embodiment of the present invention will be described.

  The present embodiment is different from the first embodiment in that the first detection piece 26 and the second detection piece 27 have the same amount of protrusion (L1 = L2), and the first optical sensor 29 and the second optical sensor 30 detect each other. That is, the position is set to be different (D1 ≠ D2). In the present embodiment, whether or not the intermediate transfer device 10 is mounted is detected using the difference in detection position.

  The relationship between the detection positions is that when the detection position of the second optical sensor 30 is closer to the back side than the detection position of the first optical sensor 29 (D1> D2, see FIG. 16), and vice versa. There are times when the detection position 29 is closer to the back side than the detection position of the second optical sensor 30 (D1 <D2, see FIG. 17), either of which may be adopted.

  A difference in detection position using the same component as the optical sensor can be realized by adjusting the mounting positions of the two components so as to be shifted in the frontal direction. According to this, the cost of parts does not increase.

  According to the present embodiment, even if the protruding amounts of the detection pieces 26 and 27 are the same, a difference is set in the detection positions of the optical sensors 29 and 30, so that the intrusion amounts of the detection pieces 26 and 27 with respect to the optical sensors 29 and 30 are set. Will be different.

  Accordingly, when there is a mounting failure of the intermediate transfer device 10, the entire intermediate transfer device 10 is in a state of being floated to the front side of the device, so that the detection piece on the optical sensor side arranged with the detection position close to the back side is the detection beam. Deviate from.

  In this state, when the link members 21 and 22 are moved in accordance with the position change of the intermediate transfer belt 41, the optical sensor arranged with the detection position close to the back side is switched ON / OFF as the detection piece passes. Although it occurs continuously, the optical sensor arranged with the detection position close to the front side is always ON (translucent state), so that a mounting failure of the intermediate transfer device 10 is detected.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 10 ... Intermediate transfer apparatus 51 ... Front side frame 52 ... Back side frame 19 ... Display means 21 ... 1st link member 22 ... 2nd link member 23 ... Cam 26 ... 1st detection piece 27 ... 2nd detection Piece 29 ... 1st optical sensor (1st detection means)
30 ... Second optical sensor (second detecting means)
31A to 31D ... photosensitive drums 34A to 34D ... primary transfer roller 41 ... intermediate transfer belt (endless belt)

Claims (5)

A transfer device that is detachably attached to a housing of an image forming apparatus,
An endless belt that is driven to rotate in a circumferential direction by transmitting a driving force from a driving member disposed inside the belt loop to the inner circumferential surface of the belt loop;
A plurality of transfer rollers disposed on opposite sides of the plurality of photosensitive drums with respect to the endless belt, the transfer rollers being displaceable in a direction of contact with each of the plurality of photosensitive members;
While being in pressure contact with a cam that rotates about the cam shaft, the cam shaft can be reciprocated within a predetermined range in the approaching direction and the separation direction, and at least one of the primary transfer rollers is separated and attached in accordance with the reciprocation. A first link member and a second link member that are displaced in the direction and disposed on both sides of the cam shaft;
A first detection piece and a second detection piece that are provided on the first link member and the second link member, respectively, face one of the peripheral portions of the endless belt, and protrude outward from the end in the width direction of the endless belt; A detection piece;
A tension applying member that is disposed inside a belt loop of the endless belt and acts on an inner peripheral surface of the endless belt to apply tension to the endless belt;
A transfer apparatus comprising:   First detection means provided on the apparatus housing side for the presence or absence of passage of the first detection piece and the second detection piece that reciprocate in conjunction with reciprocation of the first link member and the second link member, respectively. The transfer device according to claim 1, wherein detection is performed by the second detection unit and the second detection unit. A transfer apparatus according to claim 1;
A photosensitive drum having a toner image formed on the surface;
Latent image forming means for forming an electrostatic latent image on the surface of the photosensitive drum;
Developing means for developing the electrostatic latent image with toner to form a toner image;
In order to detect the presence or absence of passage of the first detection piece and the second detection piece with different protrusion amounts protruding outward from the end portion in the width direction of the endless belt, a first detection position arranged at the same detection position is used. Detection means and second detection means;
An image forming apparatus comprising: A transfer apparatus according to claim 1;
A photosensitive drum having a toner image formed on the surface;
Latent image forming means for forming an electrostatic latent image on the surface of the photosensitive drum;
Developing means for developing the electrostatic latent image with toner to form a toner image;
In order to detect the presence or absence of passage of the first detection piece and the second detection piece having the same protrusion amount protruding outward from the end portion in the width direction of the endless belt, the detection positions are arranged differently. 1 detection means and 2nd detection means,
An image forming apparatus comprising: The image forming apparatus according to claim 3, wherein:
Display means for displaying a message prompting mounting or correction of the transfer device when an unmounted state or mounting failure of the transfer device is detected based on detection results by the first detection unit and the second detection unit. An image forming apparatus.

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