JP4699819B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and more particularly to an image forming apparatus having an improved charging device.

  The image forming apparatus irradiates a peripheral surface of a photoconductive drum rotating around an axis, in which a uniform charge is previously formed on the peripheral surface by a charging device, based on image information that has been read or transmitted. Then, an electrostatic latent image is formed on the peripheral surface, a toner image is formed by supplying toner to the electrostatic latent image, and then the toner image is transferred to a sheet.

  The charging device includes a charging wire stretched across a peripheral surface of the photosensitive drum in a predetermined shield case, and is sensitized by corona discharge when a high voltage is applied to the charging wire. A uniform charge is formed on the peripheral surface of the body drum.

  By the way, toner and fine dust are suspended in the space inside the image forming apparatus, and these suspended particles are attracted by the high voltage of the charging wire and react with moisture in the air to form a charged product. The charged product adheres to the charged wire or deposits in the shield case. In particular, when the charged product adheres to the charging wire, there arises a disadvantage that a discharge failure occurs and a uniform charge cannot be formed on the peripheral surface of the photosensitive drum.

  In order to eliminate such inconvenience, the charging device is usually provided with a cleaning mechanism for periodically removing dust and the like adhering to the charging wire. This cleaning mechanism is configured by screwing a cleaning member that slides in contact with the charging wire onto a spiral rod that is arranged in parallel with the charging wire in the shield case. According to the cleaning mechanism having such a configuration, the cleaning member screwed to the spiral rod moves while cleaning the charging wire by rotating the spiral rod around the axis by driving a predetermined driving unit. The dust or the like adhering to the charging wire is wiped off by the cleaning member.

  By the way, the dust removed from the charging wire scatters in the image forming apparatus. Therefore, the scattered dust adheres to the paper located in the vicinity of the photosensitive drum. May occur.

In order to eliminate such inconvenience, the cleaning mechanism described in Patent Document 1 is provided with a sensor for detecting whether or not a sheet exists in the vicinity of the photosensitive drum, and a detection signal indicating that there is a sheet from the sensor. Is output from a predetermined control unit to prohibit the driving of the cleaning mechanism. Therefore, the charging wire is not cleaned by the cleaning member in the state where the sheet exists in the vicinity of the photosensitive drum, and the sheet is not contaminated.
JP 2000-221757 A

  However, in the thing of patent document 1, although it can prevent that the charged product scraped off from the charging wire by the cleaning member directly adheres to the paper, the dust scattered from the charging wire, etc. It cannot be stopped even if it adheres to the peripheral surface of the photosensitive drum. That is, in the case of Patent Document 1, when the peripheral surface of the photosensitive drum is contaminated with the charged product scattered from the charging wire, the contamination is transferred to the sheet during the transfer process of the toner image to the sheet, and transfer failure is caused. It cannot solve the problem that occurs.

  In addition, the charged product accumulates not only in the charging wire but also in the shield case, and the charged product in the shield case may be peeled off and scattered. It is not something that is recognized as a solution issue.

  The present invention has been made in view of such a situation, and even if the charged product scatters from the shielding case of the charging device, the scattered charged product can be damaged by adhesion to the peripheral surface of the photosensitive drum. An object of the present invention is to provide an image forming apparatus including a charging device that can be suppressed as much as possible.

According to a first aspect of the present invention, there is provided a shield case that is disposed so as to traverse the peripheral surface of the photosensitive drum in parallel with the drum core, and that has an opening in a surface facing the peripheral surface. Charging having a charging wire for corona discharge, which is stretched in parallel with the drum core and to which a high voltage from a predetermined power supply device is applied, and applies charge for image formation to the peripheral surface of the photosensitive drum In the image forming apparatus in which the apparatus is housed in a predetermined apparatus main body, the charging device includes a cleaning member that is disposed in the shield case and cleans the charging wire, and the charging wire is formed on the photosensitive drum. The cleaning member is disposed between a peripheral surface and the cleaning member, and the cleaning member has a tip end surface that contacts the charging wire from a side opposite to the peripheral surface of the photosensitive drum, and the charging member in the contact state. Along the wire A position changing mechanism configured to change the position of the charging device between a proximity position close to the photosensitive drum and a separation position spaced apart from the photosensitive drum; And a control device for controlling the operation of the position changing mechanism based on a detection result of the temperature / humidity sensor and a signal notifying whether power is supplied to the charging wire from the power supply device. And the control device is positioned at a proximity position when the supply of power to the charging wire is stopped and the humidity detected by the temperature / humidity sensor exceeds a preset reference humidity. A control signal for changing the position of the lens to the separated position is output to the position changing mechanism.

  According to such a configuration, when the supply of electric power to the charging wire is stopped and the humidity at which the charge product adheres significantly exceeds a preset reference humidity, the charging device that is positioned at the proximity position is Since the position is changed to the separation position, the influence of scattering of the charged product in an environment where the charged product is likely to accumulate in the shield case with high humidity can be suppressed to a small extent.

According to a second aspect of the present invention, in the first aspect of the present invention, a cleaning member that performs a cleaning process on the charging wire by driving a predetermined driving mechanism is provided, and the driving mechanism serves as a driving source for the position changing mechanism. It is characterized by being shared.

  According to such a configuration, since the drive mechanism for operating the cleaning member is shared with the position change mechanism that changes the position of the charging device, the number of parts is reduced as compared with the case where both are provided separately.

According to the first aspect of the present invention, when the supply of electric power to the charging wire is stopped and the humidity at which the charged product adheres remarkably exceeds a preset reference humidity, the position is set at a close position. Since the charging device is repositioned to the separation position, the influence of the scattering of the charged product in an environment where the charged product is likely to accumulate in the shield case with high humidity can be suppressed.

According to the second aspect of the present invention, since the drive mechanism for operating the cleaning member is shared with the position change mechanism for changing the position of the charging device, the number of parts can be reduced as compared with the case where both are provided separately. As a result, the manufacturing cost can be reduced.

  First, a printer as an example of an image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram of a front cross-sectional view showing an outline of an internal structure of an embodiment of a printer. As shown in this figure, a printer (image forming apparatus) 10 includes a sheet storage unit 12 that stores sheets P to be subjected to printing processing, and a sheet fed from a sheet bundle P1 stored in the sheet storage unit 12 one by one. The apparatus main body 11 includes an image forming unit 13 that performs image transfer processing on the paper P and a fixing unit 14 that performs fixing processing on the paper P on which transfer processing has been performed by the image forming unit 13. In addition, a paper discharge unit 15 for discharging the paper P subjected to the fixing process by the fixing unit 14 is provided on the top of the apparatus main body 11.

  A predetermined number (one in this embodiment) of paper cassettes 121 is provided in the paper storage unit 12 so as to be detachable from the apparatus main body 11. At the upstream end (left side in FIG. 1) of the paper cassette 121, a pickup roller 122 that feeds the paper P one by one from the paper bundle P1 is provided. The paper P fed out of the paper cassette 121 by driving the pickup roller 122 is supplied to the image forming unit 13 through the paper feed conveyance path 123 and the registration roller pair 124 provided at the downstream end of the paper feed conveyance path 123. It is supposed to be paper.

  The image forming unit 13 performs a transfer process on the paper P based on image information transmitted from a computer or the like, and is provided so as to be rotatable around a drum core extending in the front-rear direction (a direction perpendicular to the paper surface of FIG. 1). The charging device 30, the exposure device 132, the developing device 133, the transfer roller 134, and the cleaning device 135 from the upper right position in FIG. 1 of the photosensitive drum 131 in the clockwise direction along the peripheral surface of the photosensitive drum 131. Is formed.

  In the present embodiment, the photosensitive drum 131, the charging device 30, and the cleaning device 135 are housed in a predetermined housing 21 and unitized as the photosensitive unit 20. Therefore, the photosensitive drum 131, the charging device 30 and the cleaning device 135 are attached to and detached from the apparatus main body 11 as a whole by inserting and removing the housing 21 from the apparatus main body 11. Incidentally, since the casing 21 is integrated with the apparatus main body 11 in a state of being mounted at a predetermined position in the apparatus main body 11, it can be regarded as a part of the apparatus main body 11.

  The photosensitive drum 131 is for forming an electrostatic latent image and a toner image along the electrostatic latent image on the peripheral surface, and an amorphous silicon layer is laminated on the peripheral surface, whereby these images are displayed. It is suitable for forming.

  The charging device 30 forms a uniform charge on the peripheral surface of the photosensitive drum 131 that rotates clockwise around the drum center, and applies a charge to the peripheral surface of the photosensitive drum 131 by corona discharge. It is supposed to be. The charging device 30 will be described in detail later with reference to FIGS.

  The exposure device 132 irradiates the peripheral surface of the rotating photosensitive drum 131 with a laser beam to which intensity is applied based on image data transmitted from an external device such as a computer, and the photosensitive drum 131 is thereby irradiated. An electrostatic latent image is formed on the peripheral surface of the photosensitive drum 131 by erasing the electric charge in the portion where the laser light on the peripheral surface is checked.

  The developing device 133 supplies the toner to the peripheral surface of the photosensitive drum 131 to attach the toner to the portion where the electrostatic latent image is formed on the peripheral surface. Is formed.

  The transfer roller 134 transfers a positively charged toner image formed on the peripheral surface of the photosensitive drum 131 to the paper P with respect to the paper P sent to the position immediately to the left of the photosensitive drum 131. Thus, a negative charge having a polarity opposite to that of the toner image is applied to the paper P.

  Accordingly, the sheet P that has reached the lower left position of the photosensitive drum 131 is pressed and held between the transfer roller 134 and the photosensitive drum 131, and the toner image on the circumferential surface of the photosensitive drum 131 that is positively charged is negatively charged. The sheet P is peeled off toward the surface of P, whereby the transfer process is performed on the sheet P.

  The cleaning device 135 scatters when the toner remaining on the peripheral surface of the photosensitive drum 131 after the transfer processing and the charged product adhering to the charging wire 33 described later are cleaned by the charging device 30. This is for removing and adhering things adhering to the peripheral surface of the photosensitive drum 131. The cleaning device 135 is provided with a rubbing roller 135 a that rubs against the peripheral surface of the photosensitive drum 131, and residual toner and charged products that adhere to the peripheral surface of the photosensitive drum 131 by the rotation of the rubbing roller 135 a. Are scraped off (that is, the peripheral surface of the photosensitive drum 131 is polished). The peripheral surface of the photoconductive drum 131 cleaned by the cleaning device 135 goes to the charging device 30 again for the next image forming process.

  The fixing unit 14 performs a fixing process by heating the toner image of the paper P subjected to the transfer process by the image forming unit 13. The fixing roller 141 applies heat to the paper P, and the left side of the fixing roller 141. And a pressurizing member 142 arranged to face each other.

  Then, the sheet P after the transfer process is sent toward a nip portion formed between the fixing roller 141 and the pressure member 142, and passes through the nip portion to obtain heat from the fixing roller 141. The fixing process is performed. The paper P subjected to the fixing process is discharged to the paper discharge unit 15 through the paper discharge conveyance path 143.

  The paper discharge unit 15 is formed by recessing the top of the apparatus main body 11, and a paper discharge tray 151 for receiving the discharged paper P is provided at the bottom of the concave recess.

  In the present embodiment, the blower 16 including the filter 161 for taking in outside air at the upper right position in FIG. 1 in the apparatus main body 11 and the outside air taken in via the filter 161 by the blower 16 are photosensitive. A blower duct 17 is provided for guiding the body unit 20. The outside air blown toward the photoconductor unit 20 through the air duct 17 by the drive of the blower 16 penetrates the photoconductor unit 20, thereby removing the accumulated moisture of the photoconductor unit 20 and generating the charged product. In addition to suppressing the occurrence, when the inside of the photoconductor unit 20 is overheated by a heater (not shown) provided in the photoconductor drum 131, the inside of the photoconductor unit 20 is cooled, and in addition, the charged product adheres. The charged wire 33 is discharged from the inside of the photoconductor unit 20 along with the airflow by the scattered matter made of dust or the like generated by cleaning the charging wire 33.

  In addition, the power source device 18 that transforms the voltage of power supplied from an external commercial power source or rectifies the current and distributes the power to various locations at various places in the apparatus main body 11 and various types of image forming processing are provided. A control device 70 composed of a microcomputer for controlling the operation of the device is provided. A power switch 181 for turning on / off the supply of power from the commercial power source to the power supply device 18 is provided at an appropriate position on the upper surface of the apparatus main body 11.

A voltage transformed to a high voltage by the power supply device 18 is applied to a charging wire 33 (described later) of the charging device 30 and a driving motor 51 (described later) for moving the charging device 30 forward and backward with respect to the photosensitive drum 131. The power is supplied to the vehicle based on the control of the control device 70.

  2 is a perspective view showing an embodiment of the photoconductor unit 20. FIG. 2A is a partially cutaway overall perspective view of the photoconductor unit 20, and FIG. 2B is a front plate 22 of the photoconductor unit 20. FIG. It is the perspective view which looked at from the inner surface side. 3 is a cross-sectional view taken along the line AA of FIG. 2, and FIG. 2 to 3, the XX direction is referred to as the left-right direction, and the Y-Y direction is referred to as the front-rear direction. In particular, the -X direction is leftward, the + X direction is rightward, the -Y direction is forward, and the + Y direction is forwarded. It is called the back.

  First, as shown in FIG. 2A, the photoconductor unit 20 includes a photoconductor drum 131, a cleaning device 135, and the like, as described above, in a case 21 having a box shape elongated in the front-rear direction. It is formed by mounting the charging device 30.

  The casing 21 includes a front plate 22 having a rectangular shape, a rear plate 23 arranged to face the front plate 22 at the rear, and a right side plate 24 installed between the front plate 22 and the right upper portion of the rear plate 23. The left side plate 25 (FIG. 3) installed between the upper left portions of the front plate 22 and the rear plate 23, the bottom plate 26 installed between the lower right portions of the front plate 22 and the rear plate 23, and the upper surface opening are closed. The top plate 27 is provided. Between the right side plate 24 and the bottom plate 26, there are provided a plurality of support columns 28 provided at equal pitches over the entire length in the front-rear direction, thereby making the casing 21 strong in strength. .

  Further, the left side of the bottom plate 26 on the lower surface of the housing 21 is opened, so that the peripheral surface of the photosensitive drum 131 can come into contact with the peripheral surface of the transfer roller 134 (FIG. 3). The light beam from the exposure device 132 (FIG. 1) can be applied to the peripheral surface of the photosensitive drum 131.

  At the right side of the top plate 27, a lattice window 271 is formed in which notch holes are formed in a lattice shape at an equal pitch over the entire length in the front-rear direction, and a blow duct is formed from the blower 16 (FIG. 1). The outside air (indicated by an arrow in FIG. 1) fed through 17 is supplied into the casing 21 through the lattice window 271, cooled inside the casing 21, and then through the gaps at various places. 11 is exhausted.

  The photosensitive drum 131 is rotatably supported around a drum shaft 131a installed between the lower left portion of the front plate 22 and the rear plate 23, and is driven clockwise in FIG. 3 by driving a drum motor (not shown). And can be rotated.

  The cleaning device 135 is provided in the housing 21 at a position directly above the photosensitive drum 131, and the rubbing roller 135a rubs the circumferential surface of the photosensitive drum 131 against the circumferential surface of the photosensitive drum 131 (clockwise in FIG. 3). In this way, the peripheral surface of the photosensitive drum 131 is polished to remove the attached charged product.

  The charging device 30 is provided in a state extending in the front-rear direction at a substantially central position of the casing 21 with the discharge surface facing the peripheral surface of the photosensitive drum 131. The charging device 30 is long in the front-rear direction and has a shield case 31 having an opening surface 311 facing the peripheral surface of the photoconductor drum 131, and a spiral that is built in the shield case 31 so as to extend in the front-rear direction. The rod 32, a plurality of charging wires 33 stretched to extend in the front-rear direction at the opening surface 311 and the spiral rod 32 are screwed together and moved back and forth by rotation around the axis of the spiral rod 32 Thus, the cleaning member 40 for cleaning the charging wire 33, the drive mechanism 50 (FIG. 5) for driving and rotating the spiral rod 32 around the axis, and the charging wire 33 for the shield case 31 are arranged around the photosensitive drum 131. A proximity position S1 (see (A) of FIG. 6) close to the surface and a separation position S2 ((C) of FIG. 6) spaced from the peripheral surface of the photosensitive drum 131; Position changing mechanism 60 to position changes between and a (FIG. 5) and.

  In the present embodiment, the distance between the charging wire 33 and the peripheral surface of the photosensitive drum 131 is set to 0.5 to 0.6 mm in a state where the shield case 31 is set at the proximity position S1. On the other hand, the distance between the charging wire 33 and the peripheral surface of the photosensitive drum 131 is set to approximately 5.0 mm in a state where the shield case 31 is set at the separation position S2.

  The charging device 30 is fixed to a shield case 31 in which a spiral rod 32, a charging wire 33, and the like are installed, a gear case 501 described later fixed to the front end portion of the shield case 31, and a rear end portion of the shield case 31. In this way, the gear case 501 and an end wall member 502 (described later) disposed opposite to each other are provided (see FIG. 5). The driving mechanism 50 and the position changing mechanism 60 are attached to a gear case 501.

  The shield case 31 includes a pair of end wall members 312 (FIG. 4) having a rectangular parallelepiped shape, a pair of case plates 313 laid in a facing state between the pair of end wall members 312, and the pair of case plates 313. A pair of guide rails 314 elongated in the front-rear direction (in a direction orthogonal to the paper surface of FIG. 4) projecting from the edge opposite to the opening surface 311 in the direction opposite to each other, and the guide rails 314 A pair of flange plates 315 elongated in the front-rear direction projecting in opposite directions from each other, and projecting from the edge of each case plate 313 on the photosensitive drum 131 side toward the peripheral surface of the photosensitive drum 131 And a pair of grids 316 covering the charging wire 33 from both sides.

  The guide rail 314 guides the movement of the cleaning member 40, and the movement of the cleaning member 40 is stabilized by holding a pair of H-shaped guided members 43 described later. The flange plate 315 is for setting the position of the charging device 30 with respect to the proximity position S1.

  The shield case 31 is urged toward the photosensitive drum 131 by a coil spring 39 provided in the casing 21, whereby the pair of flange plates 315 are pressed against a predetermined stopper in the casing 21. By stopping, the position setting of the charging device 30 with respect to the proximity position S1 is stabilized.

  The spiral rod 32 has a rear end supported by the rear end wall member 312 so as to be rotatable about an axis, and a front end passes through the front end wall member 312. The spiral rod 32 is configured to be able to move the cleaning member 40 screwed to the spiral rod 32 by rotating around the axial center by driving of the drive mechanism 50.

  The cleaning member 40 is attached to the felt holding member 41 screwed to the spiral rod 32, a felt material 42 for cleaning the charging wire 33 held by the felt holding member 41, and the felt holding member 41. And a pair of H-shaped guided members 43.

  The felt holding member 41 includes a felt holding case 411 (FIG. 4) having a box shape that holds the felt material 42 in a state in which a part of the felt holding member 41 protrudes to the outside, and a pair of front and rear facing the felt holding case 411. And a pair of nut members 412 projecting in opposite directions from each other wall. The spiral rod 32 passes through the felt holding case 411 in a state where the nut members 412 are screwed. Therefore, when the spiral rod 32 rotates forward and backward around the axis by driving the drive mechanism 50, the felt holding member 41 moves forward and backward in the front-rear direction.

  The felt material 42 is formed by forming a felt into a rectangular parallelepiped shape. The felt material 42 is fixed by being fitted into the felt holding case 411 on the base end side after the protruding amount is adjusted so that the distal end surface is in contact with each charging wire 33. Therefore, when the felt holding member 41 moves forward and backward in the forward and backward direction due to the rotation of the spiral rod 32 by the drive of the drive mechanism 50, the charged product attached to the charging wire 33 is caused by the felt material 42. The charged wire 33 is cleaned by being wiped off.

  The front plate 22 has a position change cam 65 (see FIG. 5), which will be described later, at a position facing the one case plate 313 (the upper case plate 313 in FIG. 3) of the charging device 30 on the back side. An interference protrusion 66 is provided for moving the charging device 30 in the direction away from the photosensitive drum 131 by the interference. A similar interference projection 66 is also provided on the rear plate 23. The charging device 30 has a proximity position S1 that is close to the photosensitive drum 131 due to the interference with the interference projection 66 by the action of the position changing mechanism 60 in cooperation with the driving mechanism 50, and a separation position that is separated from the photosensitive drum 131. Although the position can be changed with respect to S2, this position changing mechanism will be described in detail later.

  The drive mechanism 50 and the position changing mechanism 60 are attached to a gear case 501 (FIG. 5) fixed to the front end wall member 312. Hereinafter, the drive mechanism 50 and the position changing mechanism 60 will be described in detail based on FIG. 5 and with reference to FIGS. FIG. 5 is a partially cutaway perspective view of the charging device 30 for explaining an embodiment of the drive mechanism 50 and the position changing mechanism 60. The direction display in FIG. 5 is the same as in FIG. 2 (X is the left-right direction (−X: leftward, + X: rightward), Y is the front-rear direction (−Y: forward, + Y: rearward)). .

  As shown in FIG. 5, the gear case 501 has an end wall 501a fixed to the front end portion of the shield case 31 so as to be orthogonal to each other, and projects forward from the peripheral portion of the end wall 501a over the entire circumference. The peripheral wall 501b is provided, and the front wall 501c is installed at a substantially right half position of the peripheral wall 501b. The drive mechanism 50 and the position changing mechanism 60 are attached to the gear case 501.

  The drive mechanism 50 includes a drive motor 51 installed substantially vertically on the front side of the front wall 501c, a worm 52 concentrically and integrally fitted on a drive shaft 511 of the drive motor 51, and the drive A worm wheel 53 that meshes with the motor 51, a drive gear 54 that is integrally fitted to the wheel shaft 531 of the worm wheel 53, a first idle gear 55 that meshes with the drive gear 54, and the first idle gear. And a rod gear 56 having a rod shaft 561 concentrically and integrally connected to the spiral rod 32 at a central position.

  In the present embodiment, the worm wheel 53 is provided at the front position of the front wall 501c, whereas the drive gear 54 is located between the end wall 501a and the front wall 501c (that is, in the gear case 501). Is provided. The first idle gear 55 and the rod gear 56 are also provided in the gear case 501, but these are design matters, and all of them may be provided in the gear case 501.

  According to the drive mechanism 50 having such a configuration, forward / reverse rotation about the axis of the drive shaft 511 by driving the drive motor 51 is transmitted to the worm wheel 53 in a decelerated state via the worm 52. The rotation around the wheel shaft 531 is transmitted to the rod gear 56 via the drive gear 54 and the first idle gear 55. The spiral rod 32 rotates around the shaft center by integral rotation of the rod gear 56 around the rod shaft 561, whereby the cleaning member 40 screwed to the spiral rod 32 moves forward and backward along the shield case 31. It will be.

  The drive motor 51 moves the cleaning member 40 located at the home position (immediately after the gear case 501) to the rear end along the spiral rod 32 by forward driving, and then reversely drives the cleaning member 40. The charging wire 33 is cleaned by the felt material 42 by the reciprocating motion of the cleaning member 40 because it returns to the home position.

  When the cleaning member 40 does not perform the cleaning process on the charging wire 33, the position changing mechanism 60 is set at a proximity position S1 (see (A) in FIG. 6) where the charging device 30 is brought close to the photosensitive drum 131. On the other hand, when the cleaning member 40 performs the cleaning process on the charging wire 33, the charging device 30 is separated from the photosensitive drum 131 and is set at the separation position S2 (see (c) in FIG. 6). It is.

  The position changing mechanism 60 includes a second idle gear 61 concentrically and integrally fitted to the rod shaft 561 on the front side of the front wall 501 c of the gear case 501, and a sect gear 62 meshing with the second idle gear 61. A sect gear shaft (support shaft) 63 that is integrally fitted to the center of curvature of the sect gear 62, a pair of front and rear cam support disks 64 that are concentrically and integrally fitted to the sect gear shaft 63, and these cam supports A position changing cam 65 for changing the position of the charging device 30 formed on the mutually opposing surfaces of the disk 64 between the proximity position S1 and the separation position S2, and the housing 21 of the photosensitive unit 20 on the housing 21. An interference projection 66 provided to interfere with the position changing cam (interference member) 65 is provided.

  In the sect gear 62, sect teeth 621 that mesh with the second idle gear 61 are provided only on a part of the peripheral surface of the gear body, whereby the second idle gear 61 rotates at a part where the sect teeth 621 exist. Only the sect gear 62 can be transmitted. Therefore, in a state where the teeth of the second idle gear 61 are opposed to the portion where the sect teeth 621 are not present, the rotation of the second idle gear 61 is not transmitted to the sect gear 62, whereby the second idle gear 61 is rotating. Nevertheless, the sect gear 62 does not rotate (that is, the spiral rod 32 rotates and the cleaning member 40 moves).

  Further, the gear ratio of the sect gear 62 with respect to the second idle gear 61 is set to be considerably large (that is, the second idle gear 61 is set to have a relatively small diameter as compared to the sect gear 62), whereby the cleaning member 40 is moved rearward from the home position H1. The second idle gear 61 meshes with the sect gear 62 until it moves by a considerable distance toward the end position H2. Thereafter, even if the second idle gear 61 rotates until the cleaning member 40 reaches the rear end position H2, The sect gear 62 is prevented from rotating.

  On the other hand, when the cleaning member 40 that has reached the rear end position H2 returns to the home position H1 by the reverse rotation of the second idle gear 61 by the reverse drive of the drive motor 51, the sect gear 62 immediately starts to rotate. .

  Hereinafter, the position change cam 65 disposed opposite to the both ends of the sect gear shaft 63 via the cam support disks 64 will be described in detail with reference to FIG. Explained. Incidentally, the front and rear position changing cams 65 are provided at both ends of the sect gear shaft 63 in a mirrored state.

  As shown in FIG. 5B, the position changing cam 65 is set in a P shape when viewed from the front, and is provided so as to surround the sect gear shaft 63. The position changing cam 65 corresponds to a stopper piece 651 corresponding to a bar line extending downward from the letter P, a linear portion 652 corresponding to a circular chord following the stopper piece 651, and a circular arc of the circle. An arc portion 653 is provided. The center of curvature of the arc portion 653 is set concentrically with the axis of the sect gear shaft 63.

  Such a position changing cam 65 is configured such that the interference protrusion 66 provided on the housing 21 of the photosensitive unit 20 is in contact with the stopper piece 651 in a state where the cleaning member 40 is set at the home position H1. While the posture is set to the interference posture, the sect gear shaft 63 rotates counterclockwise around the axis as indicated by an arrow in FIG. The installation position is set so that the posture is changed to the interference posture that interferes with the arc portion 653.

  According to the configuration of the position changing cam 65, the position changing cam 65 is rotated around the sect gear shaft 63 in the state in which the position changing cam 65 is set to the non-interfering posture. When rotating in the direction, the interference protrusion 66 starts to interfere with the straight line portion 652, whereby the charging device 30 starts to be separated from the photosensitive drum 131. When the interference protrusion 66 interferes with the circular arc portion 653 due to the continued rotation of the position changing cam 65, the separation distance of the charging device 30 from the photosensitive drum 131 becomes maximum, and thereafter this maximum separation distance is increased. While maintaining, the position changing cam 65 continues to rotate.

  Next, when the rotation of the position changing cam 65 in the clockwise direction is stopped and the position changing cam 65 rotates in the reverse direction, the interference protrusion 66 that is in contact with the arc portion 653 is in contact with the linear portion 652. The maximum separation distance of the photosensitive drum 131 is maintained. Thereafter, when the interference protrusion 66 starts to contact the linear portion 652, the charging device 30 gradually approaches the photosensitive drum 131 until the interference protrusion 66 faces the stopper piece 651, thereby changing the position. The cam 65 returns to the original non-interfering posture.

  FIGS. 6A and 6B are front views for explaining the operation of the drive mechanism 50 and the position changing mechanism 60. FIG. 6A is a state in which the charging device 30 is set at the proximity position S1, and FIG. The state where the charging device 30 is moving from the proximity position S1 to the separation position S2, and (C) shows the state where the charging device 30 is set to the separation position S2.

  First, as shown in FIG. 6A, in the state where the charging device 30 is set at the proximity position S1, the position changing cam 65 has its stopper piece 651 provided on the casing 21 of the photosensitive unit 20. The posture is set to a non-interference posture facing the interference protrusion 66 formed. In this state, the peripheral surface of the photosensitive drum 131 rotating is subjected to a charging process by corona discharge from the charging wire 33 of the charging device 30.

  Next, when the cleaning process is performed on the charging wire 33 in a state where the image forming process by the photosensitive drum 131 is interrupted, first, the drive motor 51 is driven forward, and the worm 52 is rotated by the rotation of the worm 52 thereby. The first idle gear 55 that rotates clockwise and meshes with the drive gear 54 that rotates integrally with the worm wheel 53 rotates counterclockwise. Then, the rotation of the first idle gear 55 causes the rod gear 56 meshing with the first idle gear 55 to rotate clockwise around the rod shaft 561, so that the spiral that is concentric with the rod shaft 561 is integrated. The rod 32 rotates in the clockwise direction around the axial center, whereby the cleaning member 40 meshing with the spiral rod 32 moves from the home position H1 ((A) in FIG. 5) toward the rear end position H2. To do.

  As the felt member 42 (FIG. 3) of the cleaning member 40 cleans the charging wire 33 by the movement toward the rear end position H2 of the cleaning member 40, the charged product attached to the charging wire 33 is removed.

  On the other hand, the clockwise rotation of the rod gear 56 is transmitted to the sect gear 62 via the second idle gear 61, and the sect gear 62 rotates counterclockwise around the sect gear shaft 63. Rotates counterclockwise around the sect gear shaft 63 via a cam support disk 64 integral with the sect gear shaft 63. As a result of this rotation, the position changing cam 65 is moved from the state in which the stopper piece 651 is opposed to the interference projection 66 ((A) in FIG. 6) to the linear portion 652 as shown in (B) in FIG. 66, and the charging device 30 starts to be separated from the photosensitive drum 131 due to the interference.

  Then, when the arc portion 653 of the position changing cam 65 interferes with the interference protrusion 66, the charging device 30 has the longest separation distance from the photosensitive drum 131 as shown in FIG. This state is continued until the engagement of the sect teeth 621 of the sect gear 62 with the second idle gear 61 is completed.

  Next, when the cleaning member 40 reaches the rear end position H2 (FIG. 5) in a state where the charging device 30 is set at the separation position S2, this is detected and the drive motor 51 is reversely driven. As a result, the spiral rod 32 rotates counterclockwise around the axis, so that the cleaning member 40 moves from the rear end position H2 toward the home position H1, and the felt material 42 also cleans the charging wire 33 at this time. Therefore, the charging wire 33 is eventually cleaned by the felt material 42 in a reciprocating manner.

  When the cleaning member 40 moves from the rear end position H2 toward the home position H1, the sect gear 62 rotates clockwise around the sect gear shaft 63, and thereby the position changing cam 65 also rotates clockwise. However, in a state where the arc portion 653 of the position change cam 65 interferes with the interference protrusion 66, the charging device 30 continues to be set at the separated position, and the position change cam 65 The charging device 30 approaches the photosensitive drum 131 from the time when the linear portion 652 starts to interfere with the interference protrusion 66, and approaches when the stopper piece 651 of the position changing cam 65 faces the interference protrusion 66. The position is set to the position S1.

  Due to the action of the driving mechanism 50 and the position changing mechanism 60, the charging device 30 is separated from the photosensitive drum 131 when the cleaning process is performed on the charging wire 33 by the cleaning member 40. Therefore, even if the charged product adhering to the charging wire 33 is removed and the removed charged product is scattered, it is evenly distributed on the peripheral surface of the photosensitive drum 131. Compared with the case where the cleaning process is performed on the charging wire 33 while the position is set in the proximity position, it is possible to effectively prevent the inconvenience that the removed charged product is unevenly attached to the peripheral surface of the photosensitive drum 131. Can do.

  In addition, a pair of position change cams 65 are provided at both ends of the sect gear shaft 63, and a pair of interference projections 66 corresponding to the pair of position change cams 65 are provided, so that the charging device 30 is arranged around the photosensitive drum 131. The position can be stably changed between the proximity position S1 close to the surface and the separation position S2 separated from the peripheral surface of the photosensitive drum 131.

  In the present embodiment, the control of the operation by the drive mechanism 50 and the position changing mechanism 60 of the charging device 30 configured as described above is performed by the control device 70. Hereinafter, the control by the control device 70 will be described based on FIG. 7 with reference to FIGS.

  FIG. 7 is a block diagram for explaining the control of the drive mechanism 50 and the position changing mechanism 60 by the control device 70. In this block diagram, control of applying a high voltage to the charging wire 33 is omitted. As shown in FIG. 7, the control device 70 includes a central processing unit (CPU) 71 as a central processing unit, a read only memory (ROM) 72 that is a read-only storage device attached to the CPU 71, and a CPU 71. And a RAM (Random Access Memory) 73 configured to be readable and writable for various types of data generated temporarily.

  The CPU 71 includes a charging wire cleaning determination unit 711 that determines whether or not to clean the charging wire 33, a blower drive determination unit 712 that determines whether or not to drive the blower 16, and a drive motor 51 of the drive mechanism 50. A drive motor drive determination unit 713 that determines whether or not to drive the motor, and a drive motor 51 and a blower 16 based on command signals from the charging wire cleaning determination unit 711, the blower drive determination unit 712, and the drive motor drive determination unit 713. And a control signal output unit 714 that outputs a control signal toward one or both of them.

  In order to control the operation of the drive mechanism 50 and the position changing mechanism 60 by the control device 70, the printer 10 is provided with a number sensor 81 that detects the number of sheets P that are provided at appropriate positions in the apparatus main body 11 and subjected to transfer processing. (FIG. 1), a temperature / humidity sensor 82 (FIG. 3) for detecting the temperature and humidity in the photoconductor unit 20 provided in the photoconductor unit 20, and a shield case 31 provided in the shield case 31. A front-end-side cleaning member position sensor 83 (FIG. 5) that detects whether or not the cleaning member 40 is positioned at the rear end position H2, and the cleaning member 40 provided in the shield case 31 within the shield case 31 is located at the home position H1. And a proximal end cleaning member position sensor 84 (FIG. 5) for detecting whether or not it has been positioned.

  The charging wire cleaning discriminating unit 711 compares and calculates whether or not the number detected by the number sensor 81 exceeds a preset number stored in the ROM 72 (reference number, in this embodiment, 100,000). If it exceeds, the charging wire 33 is determined to be in a state to be cleaned. After this determination, the printer 10 is turned on by a signal from the drive system of the image forming unit 13, but the image forming unit 13 is stopped (that is, the power is turned on, but the image forming process is executed). After confirming that the control signal output unit 714 is not in the state, the command signal is output to output the control signal for driving the drive motor 51 to the control signal output unit 714.

  Incidentally, in the present embodiment, a counter 731 is provided in the RAM 73, and the counter 731 counts the number of sheets P each time the sheet number sensor 81 detects the sheet P after the transfer process. The wire cleaning discriminating unit 711 compares the number counted by the counter 731 with the reference number stored in the ROM 72.

  The control signal output unit 714 that has received a command signal from the charging wire cleaning determination unit 711 outputs a motor drive control signal to the drive motor 51, and the cleaning member 40 is driven forward by the drive motor 51. Starts to move from the home position H1 toward the rear end position H2.

  Further, the charging wire cleaning determination unit 711 determines whether or not the power switch 181 that has been turned on is turned off based on a signal input from the power supply device 18. Thus, a command signal for driving the drive motor 51 is output. On the other hand, even when the power switch 181 is turned off, the power supply device 18 can supply power to the drive motor 51 only for the time required for the charging device 30 to perform the cleaning process of only one way (forward movement) on the charging wire 33. It is like that.

  Accordingly, when the power switch 181 is turned off, the drive motor 51 is driven by the control signal from the control signal output unit 714, whereby the charging device 30 is positioned at the separation position S 2 that is separated from the photosensitive drum 131. As a result, the charging wire 33 is cleaned. At this time, the drive motor 51 is driven only until the cleaning member 40 reaches the rear end position H2 from the home position H1. Accordingly, the charging wire 33 is cleaned only by the forward movement of the cleaning member 40, and the charging device 30 in a state where the cleaning member 40 has reached the rear end position H2 is separated from the photosensitive drum 131 as it is. Will remain in position.

  When the power switch 181 is turned on, the drive motor 51 is driven by the control signal from the control signal output unit 714 based on the command signal from the charging wire cleaning discriminating unit 711, thereby cleaning the rear end position H2. The member 40 performs a cleaning process on the charging wire 33 while being returned to the home position H1. The charging device 30 in a state where the cleaning member 40 has returned to the home position H <b> 1 is set at the proximity position S <b> 1 close to the photosensitive drum 131 by the action of the position changing mechanism 60.

  Furthermore, the charging wire cleaning determination unit 711 is a case where the image forming process is not executed even after a preset time has elapsed, and the power supply device 18 quickly starts up various devices in the apparatus main body 11. In the state where only the required minimum so-called standby power is supplied, a signal indicating that is input from the power supply device 18 to the charging wire cleaning determination unit 711. Even when this signal is input, the charging wire cleaning determination unit 711 outputs the same command signal to the control signal output unit 714 as when the power switch 181 is turned off. The drive motor 51 is driven based on the control signal from the control signal output unit 714, and the cleaning process is performed on the charging wire 33 by the forward movement of the cleaning member 40, and the charging device 30 moves from the proximity position S1 to the separation position S2. Will do.

  Then, in a state where standby power is being supplied from the power supply device 18 to various devices, the power supply device 18 supplies power by executing image forming processing by a push button of a start button (not shown) of the user. The standby power is returned to normal power, and a signal indicating this is input from the power supply device 18 to the charging wire cleaning determination unit 711. Upon receiving this signal, the charging wire cleaning discriminating unit 711 outputs a command signal to the control signal output unit 714 in the same manner as when the power switch 181 is turned on, and the control signal output from the control signal output unit 714 The charging device 30 returns from the separation position S2 to the proximity position S1 while the cleaning member 40 located at the rear end position H2 is returned to the home position H1 by the driving of the drive motor 51 based on the above.

  As is clear from the above description regarding the charging wire cleaning determination unit 711, power is supplied to the charging wire 33 in a state where the charging device 30 is set at the proximity position S1, while charging is performed with few exceptions. The apparatus 30 is set to a separation position S2 that is separated from the photosensitive drum 131 in a state where power is not supplied to the charging wire 33. The slight exception is that the charging device 30 remains set at the proximity position S1 until the power supply by the power supply device 18 is switched from normal power to standby power after the image forming process is executed. This is a case where power is not supplied to the charging wire 33.

  Incidentally, the case where power is not supplied to the charging wire 33 in a state where the charging device 30 is set at the proximity position S1 means that the image forming process of the next job is continued after the image forming process in a series of jobs is executed. The so-called non-printing time until the time is executed can be cited. At the time of non-printing, the power supply to the charging wire 33 is interrupted until the next job is executed after the image forming process of the previous job is finished. In this embodiment, charging is performed even in such a case. The posture of the device 30 is not changed from the proximity position S1 to the separation position S2. The reason is that it is too complicated to change the position of the charging device 30 between the proximity position S1 and the separation position S2 between jobs to be continuously executed. Changing the position of the charging device 30 to the separation position S2 during printing is not excluded from the technical scope.

  The blower drive determining unit 712 compares the temperature detected by the temperature / humidity sensor 82 with the reference temperature stored in the ROM 72, and when the temperature detected by the temperature / humidity sensor 82 exceeds the reference temperature. A command signal is output to output a control signal for driving the blower 16 toward the control signal output unit 714.

  Therefore, when the temperature inside the photoconductor unit 20 is higher than the reference temperature, the photoconductor unit 20 is cooled by air blown from the blower 16 (specifically, the photoconductor drum 131 is cooled). When the inside of the body unit 20 is lower than the reference temperature, in principle, the driving of the blower 16 is stopped.

  The blower drive determining unit 712 outputs a drive signal for driving the blower 16 via the control signal output unit 714 in a state where the charging device 30 is set at the proximity position S1, while the charging device 30 is separated from the separation position S2. With the position set to, a stop signal is output to the blower 16 via the control signal output unit 714, whereby the blower 16 is stopped when the charging device 30 is set to the separation position S2. It is made like that. This is because the charging process of the photosensitive drum 131 by the charging wire 33 is not executed in a state where the charging device 30 is located at the separation position S2, so that the charged product resulting from the corona discharge is not generated. This is because it does not occur, and in addition, it is not necessary to cool the periphery of the photosensitive drum 131.

  In addition to this, in the present invention, when the humidity detected by the temperature / humidity sensor 82 exceeds the preset reference humidity for a predetermined time (when the reference time has passed), the proximity position S1 is reached. The charging device 30 whose position is set is changed to the separation position S2, and the cleaning process of the charging wire 33 by the cleaning member 40 is executed. For this purpose, the ROM 72 stores a reference humidity value, and the RAM 73 is provided with a timer 732. Then, the blower drive determining unit 712 measures the duration by the timer 732 starting from the time when the detected value by the temperature / humidity sensor 82 exceeds the reference humidity, and if the reference time elapses, the control signal output unit 714 A control signal is output to the blower 16 to drive the blower 16.

  Accordingly, when the state where the humidity at which the charged product adheres remarkably is higher than the preset reference humidity is continued for a predetermined time, the charging device set at the proximity position S1 is repositioned to the separation position S2 and cleaned. The cleaning process of the charging wire 33 by the member 40 is executed.

  As described above, the blower drive determination unit 712 controls the drive and stop of the blower 16 based on the detection results of both the temperature and humidity by the temperature / humidity sensor 82, so that the temperature in the photoreceptor unit 20 is always properly maintained. In addition, the charging wire 33 can be cleaned in an environment where the charged product easily adheres.

  The drive motor 51 is driven by a control signal from the control signal output unit 714, whereby the cleaning member 40 is moved from the home position H1 toward the rear end position H2 in a state where the charging device 30 is set at the separation position S2. When the cleaning member 40 reaches the rear end position H2, the front end cleaning member position sensor 83 detects this, and this detection signal is input to the drive motor drive determination unit 713. Yes.

  Then, the drive motor drive determination unit 713 to which the detection signal from the distal end side cleaning member position sensor 83 is input outputs a command signal to the control signal output unit 714 to reverse drive the drive motor 51. Therefore, the control signal output unit 714 that has received this command signal outputs a reverse drive control signal toward the drive motor 51, and the cleaning member 40 is moved from the rear end position H2 by the reverse drive of the drive motor 51 thereby. It will move toward the home position H1.

  When the cleaning member 40 reaches the home position H1, this is detected by the proximal-side cleaning member position sensor 84, and the drive of the drive motor 51 is stopped by a stop signal from the control signal output unit 714 thereby.

  As described above in detail, the printer 10 according to the present invention is disposed so as to cross the circumferential surface of the photosensitive drum 131 in parallel with the drum core, and has a shield case having an opening on the surface facing the circumferential surface. 31 and a charging wire 33 for corona discharge, which is applied in parallel to the drum core in the shield case 31 and is applied with a high voltage, imparts image forming charges to the peripheral surface of the photosensitive drum 131. The charging device 30 is configured to be positioned at a separation position S2 that is separated from the photosensitive drum 131 in a state in which power is not supplied to the charging wire 33. Even if the charged product deposited in the shield case 31 falls, there is a considerable distance between the charging device 30 and the peripheral surface of the photosensitive drum 131. It is distributed on the peripheral surface of the photosensitive drum 131. Accordingly, since the charging wire 33 is close to the peripheral surface of the photosensitive drum 131, the scattered charged product is concentrated on a predetermined position of the photosensitive drum 131, thereby causing an image defect. The occurrence of inconvenience can be effectively prevented.

  Incidentally, when the peripheral surface of the photosensitive drum 131 is charged by corona discharge from the charging wire 33, the charging device 30 is set at a proximity position S1 close to the photosensitive drum 131. Sometimes, the photosensitive drum 131 rotates about its axis, so that even if the charged product accumulated in the shield case 31 falls, it falls to one point on the circumferential surface of the photosensitive drum 131. Rather, it is distributed on the circumferential surface. Accordingly, when the peripheral surface of the photosensitive drum 131 is being charged, there is no problem even if the charging device 30 is close to the peripheral surface of the photosensitive drum 131.

  In the present embodiment, the charging device 30 is moved in advance to the photosensitive member 131 when the cleaning member 40 operates in the proximity position S1 close to the circumferential surface so as to apply a charge to the circumferential surface of the photosensitive drum 131. A position change mechanism 60 is provided for changing the position between the drum 131 and the separation position S2 set to be separated from the peripheral surface of the drum 131. The position change mechanisms 60 are provided at both ends of the charging device 30, respectively. A posture between a non-interference posture that allows the charging device 30 to be positioned at the proximity position S1 by not interfering with the main body 11 and an interference posture that changes the position of the charging device 30 to the separation position S2 due to the interference of the device main body 11. It has a position changing cam 65 as a pair of interference members to be changed.

  According to such a configuration, when performing the image forming process, the charging device 30 is set at the proximity position S1 close to the peripheral surface of the photosensitive drum 131 by the position changing mechanism 60, and the height in the charging device 30 in this state is set. A uniform charge is formed on the peripheral surface of the photosensitive drum 131 by corona discharge from the charged wire to which a voltage is applied, and is prepared for the next formation of an electrostatic latent image.

  On the other hand, when the charged product attached to the charging wire 33 is cleaned and removed by the cleaning member 40, the charging device 30 set at the proximity position S <b> 1 is moved to the separation position S <b> 2 by driving the position changing cam 65. In this state, since the cleaning process is performed on the charging wire 33 by driving the cleaning member 40, the charging device 30 (that is, the charging device 30) even if the charged product adhering to the charging wire 33 is scattered. Since the charging wire 33) housed inside the photosensitive drum 131 is further away from the peripheral surface of the photosensitive drum 131 than when the charging wire 33) is positioned at the proximity position S1, the scattered charged product is spread over a wide range on the peripheral surface of the photosensitive drum 131. Will be distributed. Accordingly, since the charging wire 33 is close to the peripheral surface of the photosensitive drum 131, the scattered charged product is concentrated on a predetermined position of the photosensitive drum 131, thereby causing an image defect. The occurrence of inconvenience can be effectively prevented.

  The position changing mechanism 60 positions the charging device 30 at the separation position S2 due to the non-interference posture that allows the charging device 30 to be positioned at the proximity position S1 without interfering with the device main body 11 and the interference of the device main body 11. Since the position change cams 65 that change the posture between the interference posture to be changed are provided at both ends of the charging device 30, the charging device 30 is exposed to light in a state where the charging device 30 is set to the separated posture. Accordingly, the charged product scattered by cleaning of the charging wire 33 can be dispersed in a non-biased state, and the bias of the dispersed charged product can be dispersed on the paper. It is possible to prevent the occurrence of inconvenience such that image defects are conspicuous.

  The pair of position change cams 65 are coupled so as to be integrally rotatable around a sect gear shaft 63 installed between the position change cams 65, and the posture change of each position change cam 65 is changed around the sect gear shaft 63. Therefore, when the sect gear shaft 63 is rotated forward and reverse, the pair of position change cams 65 provided at both ends of the charging device 30 are interfered with the non-interfering posture. Compared to the case where each position changing cam 65 can be rotated individually after each position changing cam 65 can be surely synchronously rotated. Thus, the number of parts can be reduced.

  Further, a blower 16 that blows outside air toward the photoreceptor unit 20 is provided in the apparatus main body 11, and the blower 16 is stopped in a state where the charging device 30 is set at the separation position S <b> 2. Therefore, the blower 16 is stopped in a state where the charging device 30 is set at the separation position S2, that is, the charging device 30 in which power is not supplied to the charging wire 33 is not driven. Can be avoided.

  In addition, a temperature / humidity sensor 82 for detecting the temperature / humidity in the apparatus main body 11 is provided, and when the humidity detected by the temperature / humidity sensor 82 exceeds a preset reference humidity for a predetermined time, the proximity position S1 is reached. Since the position of the charging device 30 is changed to the separation position S2 and the cleaning process by the cleaning member 40 is performed, the humidity at which the charged product adheres significantly is higher than the preset reference humidity. When the high state continues for a predetermined time, the charging device 30 set at the proximity position S1 is repositioned to the separation position S2, so that it is automatically performed without confirming the state of attachment of the charged product to the charging wire 33 one by one. Thus, the cleaning process of the charging wire 33 is executed, whereby the workability of the cleaning operation of the charging wire 33 can be improved.

  Furthermore, a drive mechanism 50 for operating the cleaning member 40 is provided, and the position changing mechanism 60 is configured to perform a predetermined operation by a drive motor 51 provided in the drive mechanism 50. Therefore, both are provided separately. Compared to the case, it is possible to contribute to a reduction in the number of parts and thus to a reduction in manufacturing cost.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above embodiment, the printer 10 is applied as the image forming apparatus. However, the present invention is not limited to the printer 10 as the image forming apparatus. The image forming apparatus may be a copying machine that performs copying, or a facsimile machine that performs image forming processing based on image information that has been transmitted.

  (2) In the above-described embodiment, the photosensitive drum unit 20 is used in which the photosensitive drum 131, the cleaning device 135, and the charging device 30 are mounted. However, in the present invention, the photosensitive drum 131, The cleaning device 135 and the charging device 30 are not limited to being unitized, and they may be individually housed in the apparatus main body 11.

  (3) In the above embodiment, the charging device 30 is separated from the photosensitive drum 131 when the cleaning member 40 cleans the charging wire 33. Instead, only the shield case 31 is used as the photosensitive drum. A structure that is spaced from 131 may be employed.

  (4) In the above embodiment, the position changing mechanism 60 employs the sect gear 62 in which the sect teeth 621 are formed only in the predetermined range of the peripheral surface. However, in the present invention, the position changing mechanism 60 is provided with the sect gear 62. It is not limited to employ | adopting, You may employ | adopt the normal gear in which the tooth | gear was formed in the perimeter.

  (5) In the above embodiment, the worm 52, the worm wheel 53, the drive gear 54, the first idle gear 55 and the rod gear 56 are used to transmit the driving force of the drive motor 51 in the drive mechanism 50 to the spiral rod 32. The position changing mechanism 60 employs the second idle gear 61 and the sect gear 62 in order to transmit the driving force of the driving motor 51 to the position changing cam 65, but to transmit the driving force of the driving motor 51. The gear structure is not limited to the combination of these gears, and various combinations of gears other than this combination can be adopted depending on the situation.

  (6) In the above embodiment, the position changing cam 65 is employed as the interference member, but the present invention is not limited to the position changing cam 65 being the interference member, and the cleaning member. Various mechanisms that can change the position of the charging device 30 between the proximity position S <b> 1 and the separation position S <b> 2 in association with the number 40 can be employed. For example, a guide rail is laid in the casing 21 of the photoconductor unit 20 in parallel with the shield case 31 so that the cleaning member 40 is moved while being guided by the guide rail in addition to the spiral rod 32 and is cleaned. The shape of the guide rail may be set so that the charging device 30 is located at the proximity position S1 while the member 40 is located at the home position H1, and is located at the separation position S2 when it is away from the home position H1. .

  (7) In the above embodiment, the charging device 30 is configured such that both sides are separated from the photosensitive drum 131 by employing a pair of position changing cams 65 connected to each other by the sect gear shaft 63. However, the present invention is not limited to the case where both sides of the charging device 30 are separated from the photosensitive drum 131. For example, the position changing cam 65 is provided only on the gear case 501 side. However, it is also possible to separate only the photosensitive drum 131. In this case, the charging device 30 can be rotated starting from a predetermined position on the end wall member 502 side, and is obliquely separated from the photosensitive drum 131 in a state where the charging device 30 is set at the separation position S2.

It is explanatory drawing of front sectional view which shows the outline | summary of the internal structure of one Embodiment of a printer. FIG. 2 is a perspective view showing an embodiment of the photoreceptor unit, where (a) is a partially cutaway overall perspective view of the photoreceptor unit, and (b) is a perspective view of the front plate of the photoreceptor unit as viewed from the inner surface side. It is. It is the sectional view on the AA line of FIG. It is explanatory drawing of the front view of a charging device. It is a partially cutaway perspective view of a charging device for explaining an embodiment of a drive mechanism and a position changing mechanism. It is explanatory drawing of the front view for demonstrating the effect | action of a drive mechanism and a position change mechanism, (A) is the state in which the charging device was set to the proximity position, (B) is the charging device being separated from the proximity position A state (c) toward the position indicates a state where the charging device is set at the separation position. It is a block diagram for demonstrating control of the drive mechanism and position change mechanism by a control apparatus.

Explanation of symbols

10 Printer (image forming device)
DESCRIPTION OF SYMBOLS 11 Apparatus main body 12 Paper storage part 121 Paper cassette 122 Pickup roller 123 Paper feed conveyance path 124 Registration roller pair 13 Image forming part 131 Photosensitive drum 131a Drum shaft 132 Exposure device 133 Developing device 134 Transfer roller 135 Cleaning device 135a Rub roller 14 Fixing part 141 Fixing roller 142 Pressure member 143 Paper discharge conveyance path 15 Paper discharge part 151 Paper discharge tray 16 Blower 161 Filter 17 Air duct 18 Power supply unit 181 Power switch 20 Photosensitive unit 21 Housing 22 Front plate 23 Rear plate 24 Right side Plate 25 Left side plate 26 Bottom plate 27 Top plate 271 Lattice window 28 Post 30 Charging device 31 Shield case 311 Opening surface 312 End wall member 313 Case plate 314 Guide rail 315 Flange plate 316 Grid 32 Spiral lock 33 Charging wire 39 Coil spring 40 Cleaning member 41 Felt holding member 411 Felt holding case 412 Nut member 42 Felt material 43 Shaped guided member 50 Drive mechanism 501 Gear case 501a End wall 501b Peripheral wall 501c Front wall 502 End wall member 51 Drive motor 511 Drive Shaft 52 Worm 53 Worm wheel 531 Wheel shaft 54 Drive gear 55 Idle gear 56 Rod gear 561 Rod shaft 60 Position change mechanism 61 Idle gear 62 Sect gear 621 Sect tooth 63 Sect gear shaft (support shaft)
64 Cam support disk 65 Position change cam (interference member)
651 Stopper piece 652 Straight line part 653 Arc part 66 Interference protrusion 70 Control device 71 CPU 711 Charged wire cleaning judgment part 712 Blower drive judgment part 713 Drive motor drive judgment part 731 Counter 732 Timer 714 Control signal output part 72 ROM
73 RAM 81 Number of sheets sensor 82 Temperature / humidity sensor 83 Front end side cleaning member position sensor 84 Base end side cleaning member position sensor N Nip part P Paper P1 Paper bundle H1 Home position H2 Rear end position S1 Proximity position S2 Separation position

Claims (2)

A shield case disposed so as to cross the peripheral surface of the photosensitive drum in parallel with the drum core and having an opening in a surface facing the peripheral surface, and is stretched in parallel with the drum core in the shield case. Further, a charging device that has a charging wire for corona discharge to which a high voltage from a predetermined power supply device is applied and applies a charge for image formation to the peripheral surface of the photosensitive drum is provided in the predetermined device body. In the formed image forming apparatus,
The charging device includes a cleaning member disposed in the shield case for cleaning the charging wire,
The charging wire is disposed between a peripheral surface of the photosensitive drum and the cleaning member,
The cleaning member is configured such that a front end surface thereof is in contact with the charging wire from a side opposite to a peripheral surface of the photosensitive drum and can move along the charging wire in the contact state.
A position changing mechanism for changing the position of the charging device between a proximity position close to the photosensitive drum and a separation position spaced apart from the photosensitive drum;
Based on a temperature / humidity sensor for detecting temperature / humidity in the apparatus main body, a detection result of the temperature / humidity sensor, and a signal notifying whether or not power is supplied to the charging wire from the power supply device, the operation of the position changing mechanism is performed. A control device for controlling,
When the supply of power to the charging wire is stopped and the humidity detected by the temperature / humidity sensor exceeds a preset reference humidity, the control device separates the charging device positioned at a close position. An image forming apparatus , wherein a control signal for changing a position to a position is output to the position changing mechanism . The image forming apparatus according to claim 1 , wherein a cleaning member that cleans the charging wire by driving a predetermined driving mechanism is provided, and the driving mechanism is shared as a driving source of the position changing mechanism. apparatus.

Images