JP2010008670A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device constituting an electrical contact of a detachable unit and a body of this device simply and inexpensively, and preventing the formation of improper contact of the unit and the body of this device effectively. <P>SOLUTION: When a secondary transfer unit 27 is mounted in a unit mounting part 25a, a coil-like contact 56 of a second contact member 53 on a secondary transfer unit 27 side is brought into pressure-contact with a facial contact 43 of a first contact member 40 on a high pressure substrate 30 side through a window part 47 in the direction of extension and contraction, and the secondary transfer unit 27 and the high pressure substrate 30 are electrically and mutually connected. The diameter of the coil-like contact 56 is designed to be larger than distance between spring members forming the facial contact 43. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine and a printer provided with a detachable unit, and more particularly to a mechanism for electrically connecting the apparatus main body and the unit.

  Conventionally, in an image forming apparatus using an electrophotographic method, a toner image is formed on the surface of a photosensitive drum by supplying an electrostatic latent image formed on the surface of the photosensitive drum, which is an image carrier, from a developing device. Then, the toner image is transferred to a recording medium (such as paper or an OHP sheet) to form an image. In such an image forming apparatus, a plurality of circuit boards are fixed to the main body frame, and these are connected to each other by a harness. This harness is generally fixed (harness processing) by a fixing member such as a wire clamp or a resin cover.

  In addition, a technique that uses not only a harness but also a contact member such as a metal plate or a wire spring for the purpose of electrically connecting a process unit configured to be detachable to the apparatus main body to the above-described circuit board is disclosed. Has been. For example, Patent Document 1 discloses an image forming apparatus in which conductive means for conducting a charging wire on the process unit side with a contact on the apparatus main body side is configured by a torsion coil spring having conductivity. It is also described that a spring is formed.

Further, Patent Document 2 discloses an image forming apparatus in which a process unit and a circuit board on the main body side are connected by press-contacting a coil spring member of the process unit to a contact on the apparatus main body side formed of a metal plate. ing.
Japanese Patent Laid-Open No. 9-311524 JP 2008-3354 A

  However, in the method of Patent Document 1, since the linear electrode portion formed by bending one end of the torsion coil spring is in contact with the spring-like (annular) contact on the apparatus main body side, the conductive state is There was a risk of instability. In addition, the method of Patent Document 2 has a merit that a contact failure is unlikely to occur because the coil spring is pressed against a contact member made of a metal plate to make contact, but a mold for molding the contact member is required. In addition to being disadvantageous in terms of cost, there are also problems that assembly and fixing work are complicated. Although the case where power is supplied to the unit via the contact member has been described here, the situation is the same in the grounding mechanism that releases the electric charge charged to the unit to the apparatus main body side via the contact member.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an image forming apparatus in which an electrical contact between a detachable unit and an apparatus main body has a simple and low-cost configuration and can effectively prevent a contact failure between the unit and the apparatus main body. The purpose is to do.

  In order to achieve the above object, the present invention is formed by a unit detachable from the apparatus main body, a unit mounting part on the apparatus main body side to which the unit is mounted, and a conductive spring material attached to the unit mounting part. A first contact member, and a second contact member formed of a conductive spring material attached to the unit, and the second contact member is attached to the unit mounting portion by attaching the unit to the unit attachment portion. In the image forming apparatus in which the unit and the apparatus main body are electrically connected by being pressed against one contact member, one of the first and second contact members is a planar contact formed by bending a spring material. And the other has a coiled contact that is pressed against the planar contact in the expansion / contraction direction, and the distance between the spring materials forming the planar contact is narrower than the diameter of the coiled contact It is characterized.

  According to the present invention, in the image forming apparatus configured as described above, the unit or the unit mounting portion includes at least one of a contact support portion that supports the planar contact and the planar contact that is supported by the contact support portion. A window portion that exposes the portion and enables contact with the coil-shaped contact is formed.

  According to the present invention, in the image forming apparatus configured as described above, the planar contact has a parallel region in which linear spring members are arranged at substantially equal intervals, and the parallel region is exposed from the window portion. Yes.

  According to the present invention, in the image forming apparatus having the above-described configuration, an angle formed between a track of a tip end portion of the coil-shaped contact and a plane including the planar contact when the unit is mounted is an acute angle, and the parallel region is configured. The spring material to be extended extends along the track of the coiled contact when viewed from the vertical direction with respect to the planar contact.

  According to the present invention, in the image forming apparatus configured as described above, the planar contact is formed by bending a spring material into a spiral shape.

  According to the present invention, in the image forming apparatus configured as described above, the planar contact is formed by bending a spring material into a zigzag shape.

  According to the first configuration of the present invention, a planar contact is formed on one of the contact members formed of a spring material for electrically connecting the detachable unit and the high-voltage board on the apparatus main body, and the coil is formed on the other. In addition to providing the contact points, the distance between the spring members forming the planar contacts is made smaller than the diameter of the coil contact points, so that the coiled contacts can be reliably brought into contact with any of the wire members forming the planar contacts. it can.

  According to the second configuration of the present invention, in the image forming apparatus having the first configuration, the unit or the unit mounting portion is supported by the contact support portion in which the planar contact is inserted and supported, and the contact support portion. By forming the window portion that exposes at least a part of the planar contact, the planar contact of the first contact member can be easily and reliably supported, and the coiled contact is brought into contact through the window portion. Can do.

  According to the third configuration of the present invention, in the image forming apparatus having the second configuration described above, the parallel contact area is formed with the linear spring material arranged at substantially equal intervals on the planar contact, and the parallel area is the window portion. Since the coiled contacts come into contact with the parallel region through the window, the coiled contacts are prevented from being caught and buckled by the bent portions of the spring material constituting the planar contacts. Can do.

  Further, according to the fourth configuration of the present invention, in the image forming apparatus of the third configuration, the coil-shaped contact is brought into pressure contact with the parallel region along the extending direction of the spring material. Even when the contact is not pressed perpendicularly to the planar contact, the coiled contact can be prevented from being caught by the side surface of the spring material constituting the parallel region.

  According to the fifth configuration of the present invention, in the image forming apparatus having the third or fourth configuration, the spring material is linearly formed by bending the spring material in a spiral shape to form a planar contact. Planar contacts having parallel regions arranged at substantially equal intervals can be easily formed.

  According to the sixth configuration of the present invention, in the image forming apparatus having the third or fourth configuration, the spring material is linearly formed by bending the spring material into a zigzag shape to form a planar contact. Planar contacts having parallel regions arranged at substantially equal intervals can be easily formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a color image forming apparatus of the present invention. In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (left side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (magenta, cyan, yellow, and black), and magenta, cyan, and yellow are respectively subjected to charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  Photosensitive drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of the respective colors are disposed in the image forming portions Pa to Pd, and are formed on the photosensitive drums 1a to 1d. The toner images thus transferred are sequentially transferred (primary transfer) onto an intermediate transfer belt 8 that moves adjacent to the image forming portions Pa to Pd while rotating counterclockwise in FIG. 1 by a driving means (not shown). Thereafter, the image is transferred (secondary transfer) onto the paper at once by the transfer roller 9, and further fixed on the paper by the fixing unit 7, and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d clockwise in FIG.

  The paper on which the toner image is transferred is housed in a paper cassette 16 at the lower part of the apparatus, and passes through the pickup roller 12a, paper feed roller pair 12b, and registration roller pair 13 to the transfer roller 9 along the paper transport path 18a. It is conveyed. A sheet made of a dielectric resin is used for the intermediate transfer belt 8, and a belt in which both ends thereof are overlapped and joined to form an endless shape, or a belt without a seam (seamless) is used. Further, a cleaning device 19 for removing the toner remaining on the surface of the intermediate transfer belt 8 is disposed on the upstream side of the photosensitive drum 1a.

  Next, the image forming units Pa to Pd will be described. There are chargers 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d and image information on the photosensitive drums 1a to 1d around and below the photosensitive drums 1a to 1d that are rotatably arranged. The exposure device 4 for exposing the toner, the developing devices 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning units 5a, 5b, 5c and 5d are provided.

  When the start of image formation is input by the user, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, and then light is irradiated by the exposure device 4 to each of the photosensitive drums 1a to 1d. An electrostatic latent image corresponding to the image signal is formed on the top. Each of the developing devices 3a to 3d includes a developing roller (developer carrying member) disposed to face the photosensitive drums 1a to 1d, and magenta, cyan, yellow, and black toners are respectively supplied to the toner containers 6a, 6b, 6c, and A predetermined amount is filled by 6d. The toner is supplied onto the photosensitive drums 1a to 1d by the developing rollers of the developing devices 3a to 3d, and electrostatically adheres to the electrostatic latent image formed by exposure from the exposure device 4. A toner image is formed.

  After an electric field is applied to the intermediate transfer belt 8 at a predetermined transfer voltage, the magenta, cyan, yellow, and black toner images on the photosensitive drums 1 a to 1 d are primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning units 5a to 5d in preparation for the subsequent formation of a new electrostatic latent image.

  The intermediate transfer belt 8 is stretched over a driven roller 10 and a drive roller 11, and when the intermediate transfer belt 8 starts to rotate counterclockwise as the drive roller 11 is rotated by a drive motor (not shown), the sheet Is transferred from the registration roller pair 13 to the transfer roller 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and a full color image is formed on the sheet at the nip portion (secondary transfer nip portion) with the intermediate transfer belt 8. Secondary transferred. The sheet on which the toner image is transferred is conveyed to the fixing unit 7.

  The sheet conveyed to the fixing unit 7 is heated and pressurized when passing through the nip portion (fixing nip portion) of the fixing roller pair 14 to fix the toner image on the surface of the sheet, thereby forming a predetermined full color image. The When an image is formed on only one side of the sheet, the sheet is discharged to the discharge tray 17 by the discharge roller 15 as it is.

  On the other hand, when forming images on both sides of the paper, a part of the paper that has passed through the fixing unit 7 is once projected from the discharge roller 15 to the outside of the apparatus. Thereafter, by rotating the discharge roller 15 in the reverse direction, the paper is distributed to the double-sided conveyance path 18b and is re-conveyed to the transfer roller 9 with the image surface reversed. Then, the next image formed on the intermediate transfer belt 8 is transferred to the surface of the sheet on which the image of the sheet is not formed by the transfer roller 9 and conveyed to the fixing unit 7 to fix the toner image. To be discharged.

  The front cover 21 is supported so as to be openable and closable with respect to the apparatus main body with a lower portion as a fulcrum, and forms a double-sided conveyance path 18b between the conveyance frame 25 and supports the conveyance frame 25 so as to be rotatable. A secondary transfer unit 27 having a transfer roller 9 is detachably mounted on the transport frame 25. The conveyance frame 25 rotates integrally with the front cover 21 so that the sheet conveyance path 18 a from the registration roller pair 13 to the fixing unit 7 can be opened. Further, the conveyance frame 25 can rotate relative to the front cover 21 to open the double-side conveyance path 18b.

  2 and 3 are perspective views of the transport frame 25 as viewed from the paper transport path 18a side (left side in FIG. 1) and the double-side transport path 18b side (right side in FIG. 1). A unit mounting portion 25a (see FIG. 7) is formed on the side surface of the transport frame 25 facing the intermediate transfer belt 8, and a secondary transfer unit 27 having a transfer roller 9 is detachably mounted thereon. In addition, a high voltage substrate 30 for supplying high voltage power (transfer bias) to the secondary transfer unit 27 is attached to the back surface of the transport frame 25.

  FIG. 4 is a perspective view of the high-voltage board 30 attached to the transport frame 25. The AC voltage is input to the high-voltage board 30 from a transformer 31 and a capacitor 33 that convert DC voltage into DC voltage and high-voltage (boost) voltage, and a power supply board (not shown) disposed above the paper cassette 16 (see FIG. 1). A connector 34 and the like are arranged. A first contact member 40 is fixed to the terminal boss 35. Although other electronic components and circuits such as a choke coil and a resistor exist on the substrate 30, the description is omitted here for convenience of explanation.

  FIG. 5 is a perspective view of the first contact member 40. The first contact member 40 is integrally formed using a single metal wire (spring material) having elasticity, and includes a fixed portion 41, a connecting portion 42, and a planar contact 43. The fixing portion 41 is a portion for attaching the first contact member 40 to the terminal boss 35, and is a compression spring formed by winding a wire in a cylindrical shape (coil shape). Further, the inner diameter of the fixing portion 41 is formed to be slightly smaller than the outer diameter of the terminal boss 35, and the first contact member 40 is firmly fixed to the terminal boss 35 by press-fitting the terminal boss 35 into the fixing portion 41. In addition, the electrical connection between the first contact member 40 and the terminal boss 35 is ensured.

  The connecting portion 42 is a portion that connects the fixed portion 41 and the planar contact 43, and is formed by extending one end of the fixed portion 41 in the tangential direction. The planar contact 43 is a portion with which the second contact member 53 (see FIG. 10) on the secondary transfer unit 27 side contacts, and is formed in a substantially rectangular shape in plan view by bending the tip of the coupling portion 42 in a spiral shape. Yes. The planar contact 43 has a parallel region 43a in which linear spring materials are arranged at substantially equal intervals.

  FIG. 6 is a rear view of the transport frame 25 showing a state where the high-voltage board 30 is removed, and FIG. 7 is a front view of the transport frame 25 showing a state where the secondary transfer unit 27 is removed. The planar contact 43 of the first contact member 40 is inserted into the contact support portion 45 formed on the back surface of the unit mounting portion 25a, and the planar contact 43 is formed from the window portion 47 formed facing the contact support portion 45. A part (parallel region 43a) is exposed in the unit mounting portion 25a.

  8 and 9 are an enlarged plan view and an enlarged perspective view of an attachment portion of the first contact member 40 in the unit attachment portion 25a. A method for attaching the first contact member 40 to the transport frame 25 will be described. First, the planar contact 43 having the planar contact 43 of the first contact member 40 integrally formed on the back surface of the unit attachment portion 25a. 45 is inserted. Next, the connecting portion 42 is sandwiched between the contact support portion 45 and a rib 49 protruding in the vicinity thereof. And when attaching the high voltage board | substrate 30 from on the 1st contact member 40, the fixing | fixed part 41 is press-fitted in the terminal boss | hub 35 of the high voltage board | substrate 30, confirming from a horizontal gap. With this configuration, the first contact member 40 can be easily and reliably fixed to the unit mounting portion 25a and the high-voltage board 30.

  FIG. 10 is a perspective view of the secondary transfer unit 27 as viewed from above in FIG. A second contact member 53 for inputting high voltage power (transfer bias) from the high voltage substrate 30 (see FIG. 4) to the transfer roller 9 is attached to the back surface of the secondary transfer unit 27. The second contact member 53 is fixed to the fixed boss 50 and the locking hole 51, and is electrically connected to the core metal 9a of the transfer roller 9 via a wire member (not shown) and a conductive bearing portion 57. Is done.

  FIG. 11 is a perspective view of the second contact member 53. The second contact member 53 is integrally formed using a single metal wire (spring material) having elasticity, and includes a locking portion 54, a lead portion 55, and a coiled contact 56.

  The locking portion 54 includes a tension spring portion 54a in which a spring material is tightly wound in a cylindrical shape (coil shape), and a hook portion 54b in which the tip of the tension spring portion 54a is curved in an arc shape. Is locked in the locking hole 51 of the secondary transfer unit 27.

  The lead portion 55 is a portion that connects the locking portion 54 and the coil-shaped contact 56, and the other end of the tension spring portion 54a on which the hook portion 54b is not formed is bent vertically to extend in the expansion / contraction direction, and is further L-shaped. It is formed by bending it into a shape. In addition, an engagement recess 55a is formed by bending the lead portion 55 in a crank shape, and one end of a wire member connecting the second contact member 53 and the bearing portion 57 is engaged. The natural length L of the locking portion 54 and the lead portion 55 is formed to be shorter than the distance H (see FIG. 10) from the lower end of the fixed boss 50 to the locking hole 51.

  The coil-shaped contact 56 is a portion that contacts the planar contact 43 (see FIG. 5) of the first contact member 40 attached to the high-voltage board 30, and the tip of the lead portion 55 is wound in a cylindrical shape (coil shape). It is a compression spring. The inner diameter of the coil-shaped contact 56 is slightly smaller than the outer diameter of the fixed boss 50, and the second contact member 53 is firmly attached to the fixed boss 50 by press-fitting the fixed boss 50 into the coil-shaped contact 56. It is fixed to.

  FIG. 12 is an enlarged perspective view of a portion where the second contact member 53 is attached in the secondary transfer unit 27. When the second contact member 53 is fixed, the fixed boss 50 is first press-fitted into the coiled contact 56 from the lead portion 55 side. At this time, the lead part 55 is aligned with the position of the groove part 61. Next, the hook portion 54 b is hooked into the locking hole 51 of the secondary transfer unit 27 while the locking portion 54 is pulled down to extend the tension spring portion 54 a.

  With this configuration, the urging force of the tension spring portion 54a acts in a direction in which the coiled contact 56 is pressed against the fixed boss 50 (downward in FIG. 12), so that the second contact member 53 is securely fixed to the secondary transfer unit 27. can do. Finally, one end of the wire member connected to the bearing portion 57 is hooked on the engaging recess 55a to complete the attachment of the second contact member 53.

  When the secondary transfer unit 27 having the above-described configuration is attached to the unit mounting portion 25a, the coiled contact 56 of the second contact member 53 comes into contact with the planar contact 43 of the first contact member 40 through the window 47. The secondary transfer unit 27 and the high voltage substrate 30 are electrically connected.

  The contact state of the planar contact 43 and the coil contact 56 at this time is shown in FIG. In FIG. 13, only the first contact member 40, the window 47, and the second contact member 53 are shown so that the state of the contact can be seen. As shown in FIG. 13, the coiled contact 56 is pressed against the planar contact 43 in the expansion / contraction direction. Here, the diameter R (see FIG. 11) of the coil-shaped contact 56 is designed to be larger than the distance D (see FIG. 5) between the spring materials forming the planar contact 43. Thereby, the coil-shaped contact 56 can be reliably brought into contact with any of the spring materials forming the planar contact 43.

  Further, both end portions in the longitudinal direction of the planar contact 43 overlap the opening edge of the window portion 47, and only the substantially central portion (parallel region 43 a) of the planar contact 43 is exposed from the window portion 47. Thereby, it is possible to effectively prevent a contact failure caused by the coiled contact 56 being pressed against the edge or the bent portion of the planar contact 43 and buckling.

  When the secondary transfer unit 27 is mounted, the support bosses 60 provided at both ends of the secondary transfer unit 27 are engaged with the support holes 25b of the transport frame 25, and the secondary transfer unit with the support boss 60 as a fulcrum. The unit 27 is mounted on the unit mounting portion 25a while being rotated. Therefore, the coiled contact 56 of the second contact member 53 does not approach perpendicularly to the planar contact 43 of the first contact member 40 but approaches from the direction of arrow A in FIG. That is, the angle formed between the track of the tip of the coil-shaped contact 56 and the plane including the planar contact 43 when the secondary transfer unit 27 is mounted is an acute angle. Here, in the parallel region 43a in contact with the coiled contact 56, the spring material extends along a track (in the direction of arrow A) where the coiled contact 56 approaches when viewed from the vertical direction with respect to the planar contact 43. Therefore, the coil-shaped contact 56 is pressed against the parallel region 43a while sliding along the spring material. Thereby, there is no possibility that the coil-shaped contact 56 is caught on the side surface of the spring material forming the planar contact 43, and the contact can be reliably turned on / off.

  In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the planar contact 43 is formed by bending a metal spring material into a spiral shape. However, as shown in FIG. 14, for example, the planar contact having a parallel region 43a by bending the spring material into a zigzag shape. 43 can also be formed. Further, in the case where the coil-shaped contact 56 is press-contacted substantially perpendicularly to the planar contact 43, the parallel region 43a is not necessarily required, and the planar contact 43 can be formed by various other bending methods. it can.

  Further, the configuration of the fixing portion 41 of the first contact member 40 and the locking portion 54 of the second contact member 53 is not limited to the above embodiment, and the first contact member 40 and the second contact member 53 are securely connected. Any configuration that can be fixed is acceptable. Further, in the above embodiment, the first contact member 40 having the planar contact 43 is disposed on the unit mounting portion 25a side, and the second contact member 53 having the coiled contact 56 is disposed on the secondary transfer unit 27 side. The first contact member 40 may be provided with the coil-shaped contact 56, and the second contact member 53 may be provided with the planar contact 43.

  In the above embodiment, the secondary transfer unit 27 has been described as an example of the detachable unit. However, other detachable units such as a toner container, a developing unit, a drum unit, and the like and the high-voltage substrate 30 on the apparatus main body side. It can also be used for electrical connection. Alternatively, the first contact member 40 is connected to a metal member such as a main body frame, and the second contact member 53 is connected to a conductor such as a metal plate arranged around a member that requires countermeasures against static electricity. It becomes a grounding mechanism that releases the electric charge charged in the unit to the apparatus main body side. Further, the present invention is not limited to the monochrome printer as shown in FIG. 1, and other images having a detachable unit such as a tandem or rotary developing type color printer, a monochrome and color copying machine, and a facsimile. Of course, it can also be applied to a forming apparatus.

  The present invention includes a unit detachable from the apparatus main body, a unit attachment part on the apparatus main body side to which the unit is attached, a first contact member formed of a conductive spring material attached to the unit attachment part, A second contact member formed of a conductive spring material attached to the unit, and the second contact member is pressed against the first contact member by mounting the unit on the unit mounting portion, and the unit and the apparatus main body In the image forming apparatus in which the first and second contact members are electrically connected to each other, one of the first and second contact members has a planar contact formed by bending a spring material, and the other is in a stretching direction with respect to the planar contact. In addition to having a coiled contact to be pressed, the distance between spring members forming the planar contact is made smaller than the diameter of the coiled contact.

  Accordingly, it is possible to provide an image forming apparatus that can contact a coil-shaped contact with any of the wire rods that form a planar contact, and that enables a stable and reliable connection between the unit and the apparatus main body at a low cost. Can do. The planar contact can be easily formed by bending the spring material into a spiral shape or a zigzag shape.

  In addition, since the contact support portion into which the planar contact is inserted and supported and the window portion exposing at least a part of the planar contact are formed in the unit or the unit mounting portion, the planar contact can be easily and reliably placed at a predetermined position. It can support, and a coil-shaped contact can be made to contact reliably through a window part.

  In addition, since a parallel region in which linear spring materials are arranged at substantially equal intervals is formed on the planar contact, and the parallel region is exposed from the window portion, the occurrence of contact failure due to the buckling of the coiled contact is further effective. Can be prevented. Furthermore, when the coiled contact approaches the surface contact at an angle, the track of the coiled contact when viewed from the vertical direction with respect to the surface contact and the extending direction of the spring material in the parallel region should be matched. Thus, it is possible to prevent the coiled contact and the planar contact from being caught.

FIG. 2 is a side cross-sectional view showing the overall configuration of the image forming apparatus of the present invention. FIG. 5 is a perspective view of the transport frame as viewed from the paper transport path side. FIG. 3 is a perspective view of the transport frame as viewed from the back side. FIG. 3 is a perspective view of a high-voltage board attached to the transport frame. FIG. 3 is a perspective view of a first contact member. FIG. 6 is a back view showing a state where the high-voltage board is removed from the transport frame. FIG. 6 is a front view showing a state where the secondary transfer unit is removed from the transport frame. These are the enlarged plan views of the attachment part of the 1st contact member in a unit attachment part. These are the expansion perspective views of the attachment part of the 1st contact member in a unit attachment part. FIG. 3 is a perspective view of the secondary transfer unit as viewed from above in FIG. 2. FIG. 4 is a perspective view of a second contact member. FIG. 4 is an enlarged perspective view of a mounting portion of a second contact member in the secondary transfer unit. These are perspective views which show the contact state of a planar contact and a coil-shaped contact. FIG. 10 is a perspective view showing another shape of the first contact member.

Explanation of symbols

1a to 1d Photosensitive drums 3a to 3d Developing device 4 Exposure device 5a to 5d Cleaning device 8 Intermediate transfer belt 9 Transfer roller 25 Conveying frame (device main body)
25a unit mounting portion 27 secondary transfer unit 30 high voltage substrate 35 terminal boss 40 first contact member 41 fixed portion 42 connecting portion 43 planar contact 43a parallel region 45 contact support portion 47 window portion 50 fixed boss 53 second contact member 54 engagement Stop part 54a Tension spring part 54b Hook part 55 Lead part 56 Coiled contact point 100 Image forming apparatus

Claims (6)

A unit that can be attached to and detached from the apparatus body;
A unit mounting portion on the apparatus main body side for mounting the unit;
A first contact member formed of a conductive spring material attached to the unit mounting portion;
A second contact member formed of a conductive spring material attached to the unit,
In the image forming apparatus in which the second contact member is pressed against the first contact member by mounting the unit to the unit mounting portion, and the unit and the apparatus main body are electrically connected.
Either one of the first and second contact members has a planar contact formed by bending a spring material, and the other has a coiled contact that is pressed against the planar contact in the expansion / contraction direction. An image forming apparatus, wherein a distance between spring members forming the planar contact is narrower than a diameter of the coil contact.   In the unit or the unit mounting portion, a contact support portion that supports the planar contact, and at least a part of the planar contact supported by the contact support portion is exposed to make contact with the coiled contact. The image forming apparatus according to claim 1, wherein an enabling window is formed.   The image forming apparatus according to claim 2, wherein the planar contact has a parallel region in which linear spring members are arranged at substantially equal intervals, and the parallel region is exposed from the window portion.   The angle formed by the track of the tip of the coil contact and the plane including the planar contact when the unit is mounted is an acute angle, and the spring material constituting the parallel region is perpendicular to the planar contact The image forming apparatus according to claim 3, wherein the image forming apparatus extends along a track of the coil-shaped contact when viewed from above.   The image forming apparatus according to claim 3, wherein the planar contact is formed by bending a spring material into a spiral shape.   The image forming apparatus according to claim 3, wherein the planar contact is formed by bending a spring material into a zigzag shape.

Images