JP2008308258A - Transfer device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer device capable of preventing a transfer material from getting dirty and an abnormal image from being formed. <P>SOLUTION: This transfer device 5 comprises a transfer section 6 for transferring a toner image on a photoreceptor drum 3 to a transfer material, conveying the transfer material, and a transference exit guide member 50 having a guide surface 55a for guiding the transfer material, to which the toner image is transferred by the transfer section 6, toward the downstream side. The transfer outlet guide member 50 is provided freely to be rotated around a rotary shaft 53 between a guide position wherein the guide surface 55a is directed upward so as to guide the transfer material, and a fall position separated from the guide position wherein a foreign matter adhered to the guide surface is fallen. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transfer device that transfers a toner image on an image carrier onto a transfer material, and an image forming apparatus such as an electrophotographic printer, a facsimile machine, a copying machine, and a composite machine using these transfer devices.

  In general, in an image forming apparatus such as a copying machine, as shown in FIG. 7, a transfer belt 101 transfers a toner image formed on a photoconductor 100 to a transfer material while transferring the transfer material such as a sheet onto the transfer material. A device 103 is provided.

  In such a transfer device 103, a transfer outlet guide member 107 having a guide surface 106 that guides a transfer material after transfer toward a fixing device 105 that fixes a toner image of the transfer material onto the transfer material is fixed. There is something. The transfer outlet guide member 107 guides the transfer material toward the fixing device 105 when the transfer material on which the toner image is transferred passes on the guide surface 106.

  When such a high-rigidity thick paper or special paper with perforation is passed through such a transfer outlet guide member 107, the transfer material passes through the inlet guide plate 108 of the fixing device 105 and the fixing roller 109 and the pressure roller. When the transfer material enters the nip 110, the transfer material floats from the guide surface 106 of the transfer outlet guide member 107, or the transfer material fluctuates up and down along the perforation, thereby neutralizing the transfer outlet guide member 107. It is transported outside the effective static elimination area of the static elimination member 112. For this reason, the charge removal member 112 cannot remove the residual charge on the transfer material, and the toner image may be disturbed (chilli).

  The scattered toner is scattered on the transfer outlet guide member 107. The scattered toner adheres to the transfer outlet guide member 107 and the charge removal member 112 as toner dust. Then, when the next transfer material passes over the transfer outlet guide member 107, the toner dust adheres to the front and back of the transfer material, and the transfer material becomes contaminated with toner, or the toner accumulated on the charge removal member 112 further eliminates the charge. Insufficient capacity and toner dust may occur, resulting in abnormal images.

  For example, when the A4 size vertical transfer material is passed, the scattered toner accumulates on the upper surface of the transfer outlet guide member 107 in front of and behind the transfer material. In this state, when the paper size of the transfer material is changed and, for example, when A3 size paper is passed in the vertical direction, the front end and the rear end of the tip of the A3 size transfer material pick up the accumulated toner. It sticks to the tip of the transfer material. That is, when the large-size sheet is passed after the small-size sheet is passed, so-called edge surface contamination occurs.

  Therefore, conventionally, a rib 111 standing upward from the guide surface 106 is provided on the guide surface 106 of the transfer outlet guide member 107 to reduce the contact area with the transfer material, thereby reducing paper dust (paper spilled from the transfer material). In general, the fiber) is prevented from adhering to the transfer material. However, if a large amount of paper dust accumulates during long use, the stain prevention effect by the ribs 111 is also reduced.

  In order to avoid the above problems, it is important to guide the transfer outlet guide member 107 and the transfer material so as to be conveyed in close proximity so that the static electricity of the transfer material can be efficiently removed. The difference in strength due to the type and thickness of the transfer material, especially transfer paper with perforations in advance or special transfer paper with postcards, cards or slips attached in recent years. In this case, in particular, the transfer material conveyance state becomes irregular, and the transfer outlet guide member 107 cannot follow the transfer material conveyance state, and the above-described abnormal image such as toner dust is displayed. Since it is likely to occur, it is difficult to completely avoid this abnormal image.

  In order to prevent such stains and abnormal images on the transfer material, as disclosed in Patent Document 1, the cleaning web originally installed for cleaning the fixing roller of the fixing device is disposed above the transfer outlet guide member. There is a known technology that prevents untransferred toner from being transferred or causing abnormal images to be generated by adhering unfixed toner scattered from the transfer material onto the web surface to prevent the transfer outlet guide member from becoming dirty. ing.

  Further, as disclosed in Patent Document 2, the surface of the transfer outlet guide member is removed by rubbing the guide surface of the transfer outlet guide member with a cleaning member (conductive brush), and the transfer material is stained or abnormal images are removed. A technique for preventing the occurrence is also known.

JP 2006-243001 A JP 2002-365929 A

  However, in the case of the technique of the above-mentioned Patent Document 1, the scattered toner that has not reached the cleaning web surface and could not be collected falls on the transfer outlet guide member plate, so the scattered toner on the transfer conveyance guide plate is completely removed. It is difficult to collect, and as a result, there is a problem that the transfer material becomes dirty and abnormal images are generated.

  Similarly, even in the case of the technique of the above-mentioned Patent Document 2, there is no means to remove and collect the toner adhering to the rubbing after cleaning, so that the cleaned toner is scattered in the machine and the toner adheres to the cleaning member. Since the transfer outlet guide member is cleaned as it is, the toner removed from the transfer outlet guide member again adheres to the transfer outlet guide member, and there is a problem that the transfer material becomes dirty and abnormal images are generated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a transfer device and an image forming apparatus that can prevent the transfer material from becoming dirty and the occurrence of abnormal images.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a transfer portion that transfers a toner image on an image carrier to a transfer material while conveying the transfer material, and the toner image is transferred by the transfer portion. A transfer outlet guide member having a guide surface that guides the transferred material toward the downstream side, and the transfer outlet guide member has a guide position that guides the transfer material with the guide surface facing upward. It is characterized in that it is provided so as to be rotatable about a rotation axis at a drop position where the foreign matter adhering to the guide surface is dropped away from the guide position.

  According to a second aspect of the present invention, in the first aspect of the present invention, the transfer outlet guide member that is provided at the drop position of the transfer outlet guide member and rotates from the guide position toward the drop position is abutted. , Characterized in that it comprises a blocking portion for blocking the rotation.

  According to a third aspect of the present invention, in the second aspect of the invention, the foreign matter collecting port is formed so as to face the guide surface of the transfer outlet guide member at the dropping position. And a covering member that closes the foreign matter collection port when the transfer outlet guide is in the guide position and opens the foreign matter collection port when the transfer outlet guide is in the fall position. It is characterized by.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, when a pair of guide surfaces of the transfer outlet guide member are provided and one guide surface is directed upward to guide the transfer material, The other guide surface is directed downward, and the direction of one guide surface and the other guide surface are switched by rotation of the transfer outlet guide member.

  The invention described in claim 5 is the invention described in any one of claims 1 to 4, wherein the transfer outlet guide member is provided with a discharging member for discharging the transfer material. To do.

  The invention described in claim 6 is the invention described in any one of claims 1 to 5, wherein the drive unit connected to the rotation shaft to drive the rotation shaft, and the transfer outlet guide member are arranged at the guide position and Based on the position detection unit that detects whether the position is in the drop position and the detection information of the position detection unit, the drive unit is driven so that the transfer outlet guide member is located in either the guide position or the drop position. And a control unit for controlling the operation.

  The invention described in claim 7 is an image forming apparatus for forming an image on a transfer material by an image carrier on which a toner image is formed. The transfer apparatus according to any one of claims 1 to 6 is provided. An image forming apparatus.

  According to the present invention, toner or paper adhered to the transfer outlet guide member with the guide surface facing downward by rotating the transfer outlet guide member from the guide position with the guide surface facing upward toward the drop position. Foreign matter such as powder falls and the foreign matter on the transfer outlet guide member can be removed. Moreover, it can prevent that the foreign material which fell from the guide surface adheres to a guide surface again because a guide surface faces below. As a result, it is possible to prevent the transfer material from being contaminated by the foreign matter adhering to the transfer outlet guide member and the occurrence of an abnormal image.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing an image forming portion of the image forming apparatus according to the first embodiment of the present invention, and FIG. 2 is a view for explaining the operation of the transfer outlet guide member in the transfer apparatus of FIG. 3 is a cross-sectional view, FIG. 3 is a cross-sectional view for explaining a transfer operation by the transfer apparatus of FIG. 1, and FIG. 4 is a block diagram showing a configuration of a main part of the image forming apparatus according to the first embodiment of the present invention. FIG. 5 is a flowchart showing the flow of control by the control unit shown in FIG.

  As shown in FIGS. 1 and 4, an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a composite machine thereof includes an image forming unit 1 for forming an image on a transfer material such as paper, and an image forming unit. 1 is provided, and a control unit 2 that controls the driving of 1 and an operation unit 4 for inputting a command when the user performs image formation or the like are provided. The image forming unit 1 generally includes a photosensitive drum 3 that is an image carrier on which a toner image corresponding to a document image is formed, a transfer device 5 that transfers the toner image on the photosensitive drum 3 to a transfer material, and this transfer Heat and pressure are applied to the transfer material provided on the downstream side of the apparatus 5 and conveyed between the nip between the fixing roller 7a and the pressure roller 7b via the fixing inlet upper guide 7c and the fixing inlet lower guide 7d. A fixing device 7 for fixing the toner image transferred to the transfer material to the transfer material, and a cleaning device 9 for cleaning residual toner remaining on the photosensitive drum 3 after the transfer.

  The image forming unit 1 includes a charging device that uniformly charges the outer peripheral surface of the photosensitive drum 3, a reading unit that reads an image of a document, and an electrostatic latent image corresponding to the image read by the reading unit. An exposure device for forming the photosensitive drum 3 charged by the toner, a developing device for forming a toner image by developing the electrostatic latent image on the photosensitive drum 3 with toner, and the like are shown in the present embodiment. And description is abbreviate | omitted. Further, the control unit 2 shown in FIG. 4 is connected to a drive unit and various sensors for driving each device of the image forming unit 1 such as the drive motor for the photosensitive drum 3 described above. Then, illustration and description thereof are omitted.

  The transfer device 5 guides the transfer material 6 on which the toner image on the photosensitive drum 3 is transferred to the transfer material while conveying the transfer material, and the transfer material onto which the toner image has been transferred by the transfer device toward the downstream side. A transfer outlet guide member 50 having a guide surface 55a, a drive unit 57 that drives the transfer outlet guide member 50, and a rotational position detection sensor 61 that is a position detection unit that detects the rotational position of the transfer outlet guide member 50 (FIG. 4). Reference) and a case 8 for storing them.

  The transfer unit 6 is provided at a position facing the photosensitive drum 3, an endless transfer belt 15 that is hung between the driving roller 11 and the driven roller 13, an inner side of the transfer belt 15, and the photosensitive drum. 3 and a bias roller 17a and a transfer bias brush 17b provided in the vicinity of the nip portion of the transfer belt 15, and a guide surface of a transfer outlet guide member 50 which is provided at a lower portion on the downstream side of the transfer belt 15 and which is in a drop position described later. A foreign matter collecting port 19a formed so as to oppose 55a, and a foreign matter collecting unit 19 for collecting foreign matter such as toner and paper dust generated during the transfer operation through the foreign matter collecting port 19a. ing.

  The foreign matter collecting unit 19 has a toner carrying screw 19b, and the foreign matter taken in from the foreign matter collecting port 19a is carried in the depth direction in FIG. 1 by the rotation of the toner carrying screw 19b, and is collected by a collecting path (not shown). The waste toner box is collected.

  The transfer outlet guide member 50 includes a box-shaped main body 54, a guide plate 51 provided on the upper surface of the box-shaped main body 53, a static elimination member 52 provided in the main body 54 to neutralize the transfer material, A rotating shaft 53 and a partition sheet (covering member) 56 that cover the foreign matter collection port 19a are provided integrally on both side surfaces of the main body 54, respectively.

  When the transfer outlet guide member 50 is in the guide position (position shown in FIG. 1, which will be described later), the guide plate 51 rises upward from the upper surface of the guide plate 51, and the guide plate 51. The ribs 55 extending in the transfer material conveyance direction (left and right direction in FIG. 1) on the upper surface of the guide plate 51 are spaced from each other in a direction (depth direction in FIG. 1) perpendicular to the transfer material conveyance direction on the upper surface of the guide plate 51. Several are arranged. The upper surfaces 55 of these ribs 55 are formed so as to be substantially flush with the upper surface of the transfer belt 15, and serve as a guide surface 55 a that guides the transfer material from the transfer belt 15 toward the fixing device 7. The contact area with the transfer material is reduced to make it difficult for foreign matter to adhere.

  The static elimination member 52 is formed in a plate shape from a thin plate such as stainless steel. The downstream portion of the charge removal member 52 is lightly bent toward the upper guide surface 55a, and the tip 52a has a sawtooth shape in which peaks and valleys are alternately continuous over the depth direction in FIG. Is formed. Further, openings (windows) are formed in the portions between the ribs 55 in the guide plate 51, and the crests of the tip 52a of the charge removal member 52 are exposed from these openings and guided to the guide surface 55a. The transfer material to be discharged can be discharged efficiently.

  The rotating shaft 53 is provided so as to extend vertically from both side surfaces on the downstream side (left side in FIG. 1) on both side surfaces of the main body 54. Of the rotating shafts 53, one rotating shaft 53 is pivotally supported by a bearing provided inside the case 8, and the other rotating shaft 53 is connected to the drive unit 57.

  2, the transfer outlet guide member 50 is held in a horizontal state as shown in FIG. 2, and a guide position (a wavy line in FIG. 2) guides the transfer material with its guide surface 55a facing upward. Position) and hangs away from the guide position, and can rotate (rotate) to a drop position (a position indicated by a solid line in FIG. 2) where the foreign matter adhering to the guide surface 55a drops. Note that the drop position is not limited to the position where the transfer outlet guide member 50 is hung down, and any one of the positions where the transfer outlet guide member 50 is rotated and tilted slightly from the horizontal state can be set as the guide position. .

  In the present embodiment, the downstream end (edge) of the case 8 is abutted by the transfer outlet guide member 50 that rotates from the guide position toward the drop position (see FIG. 2) to prevent the rotation. It is set as the prevention part 8a to do. The state where the transfer outlet guide member 50 abuts against the blocking portion 8a is the drop position of the transfer outlet guide member 50. At this drop position, the transfer outlet guide member 50 is from the upstream end of the guide surface 55a. Also, the downstream end portion is inclined and suspended so as to be positioned on the downstream side (in FIG. 2, the transfer outlet guide member 50 is suspended so as to be inclined obliquely to the left).

  The partition sheet 56 has an upstream lower end (a lower right end of the transfer outlet guide member 50 in FIG. 1) and an upper end (a case in FIG. 1) of the blocking portion 8a of the case 8 in the main body 54 of the transfer outlet guide member 50 at the guide position. 8 and the upper left corner). The partition sheet 56 is made of a flexible material such as a rubber sheet or a polyurethane sheet, and when the transfer outlet guide member 50 is in the guide position, as shown in FIG. By blocking the cover, it functions as a wall that separates the inside and outside of the foreign material collecting unit 19 and prevents leakage, overflow and scattering of foreign materials such as toner and paper dust in the foreign material collecting unit 19. .

  On the other hand, when the transfer outlet guide member 50 is rotated toward the dropping position, the partition sheet 56 bends as the transfer outlet guide member 50 rotates due to its own flexibility as shown in FIG. Thus, the rotation of the transfer outlet guide member 50 is prevented from being hindered. When the transfer outlet guide member 50 is in the dropping position, the partition sheet 56 is folded as shown in FIG. 2 to open the foreign matter collection port 19a and to transfer the foreign matter collection port 19a. Foreign matter from the guide surface 55a of the outlet guide member 50 can be collected.

  The drive unit 57 includes a rotation gear 58 to which the other rotation shaft 53 is fixed, and a drive motor 60 having a worm gear 59 meshed with the rotation gear 58. The drive motor 60 is controlled by the control unit 2. The drive is controlled.

  Although not shown in FIGS. 1 and 2, the rotational position detection sensor 61 has a position corresponding to the transfer outlet guide 50 in the guide position and a position corresponding to the transfer outlet guide 50 in the drop position. Each is provided so that it can be detected whether the transfer outlet guide 50 is in the guide position or the drop position. Then, the detection information is transmitted to the control unit 2. As the rotational position detection sensor, for example, a photo sensor or the like can be used, and there is no particular limitation as long as the position of the transfer outlet guide 50 can be detected.

  In the transfer device 5 of the present embodiment, the toner image formed on the photosensitive drum 3 is electrostatically transferred to the transfer material at the nip portion formed at the contact portion between the photosensitive drum 3 and the transfer belt 15. The transfer process, the transfer process for delivering the transfer material electrostatically attracted to the transfer belt 15 to the next process, and the charge removal member 52 provided on the transfer outlet guide member 50 to positively remove the charge on the transfer material, The transfer operation is performed by a charge eliminating process for the purpose of preventing disturbance of the toner image on the material.

  In the transfer step, as shown in FIG. 3, the toner image is transferred onto the transfer material by applying a transfer bias to the bias roller 17 by a high voltage power source. This transfer material is conveyed by a transfer belt 15 that is driven to rotate. Note that the transfer belt 15 is formed of a material whose electric resistance is medium resistance. The driving roller 11 and the driven roller 13 are used while being grounded. The static elimination member 52 of the transfer outlet guide member 50 is also grounded.

  The transfer material conveyed by the transfer belt 15 from the nip portion between the photosensitive drum 3 and the transfer belt 15 toward the transfer outlet guide member 50 has static electricity on the transfer material on the guide surface 55 a of the transfer outlet guide member 50. The toner image is removed and conveyed to the fixing inlet lower guide plate 7d, enters the nip between the fixing roller 9 and the pressure roller 10, and the toner image is fixed on the transfer material.

  Next, the operation of the transfer outlet guide member 50 in the present embodiment will be described based on the flowchart shown in FIG. When the user operates the operation unit 4 and a print command signal is input to the control unit 2, the image forming unit 1 is driven by the control unit 2. Specifically, the photosensitive drum 3 is rotationally driven, the photosensitive drum 3 being rotationally driven by the charging device is uniformly charged, an electrostatic latent image is formed on the photosensitive drum 3 by the exposure device, The electrostatic latent image on the photosensitive drum 3 is visualized as a toner image by the developing device, the toner image is transferred to the transfer material by the transfer device 5, the toner image is fixed on the transfer material by the fixing device 7, and then the transfer material is discharged. A series of image forming operations (printing operations) such as paper is performed under the control of the control unit 2.

  After the series of image forming operations as described above is completed (after the printing is completed), the control unit 2 energizes the drive motor 60 of the drive unit 57, whereby the worm gear 59 rotates. Rotates. As the rotary gear 58 rotates, the rotation shaft 53 rotates, and the transfer outlet guide member 50 rotates clockwise from the guide position toward the drop position as shown in FIG. 2 (steps S1 and S2).

  When the transfer outlet guide member 50 rotating toward the dropping position hits the blocking portion 8 a of the case 8, the control unit 2 energizes the drive motor 60 based on detection information from the rotation position detection sensor 61 that detects this. The transfer outlet guide member 50 is fixed (held) at the drop position where the guide surface 55a faces downward (steps S3 and S4).

  At this time, due to the impact that the transfer outlet guide member 50 hits against the blocking portion 8a, foreign matters such as toner and paper dust deposited on the guide surface 55a of the transfer outlet guide member 50 fall into the foreign matter collecting portion 19, Foreign matter adhering to the guide surface 55a and the like of the transfer outlet guide member 50 is efficiently removed, and the transfer outlet guide member 50 is cleaned. In addition, since the guide surface 55a faces downward, it is possible to prevent the foreign matter dropped from the guide surface 55a from attaching to the guide surface 55a again. As a result, it is possible to prevent the transfer material from being contaminated by the foreign matter attached to the transfer outlet guide member 50 and the occurrence of an abnormal image. Furthermore, since it is a simple configuration that does not require a separate brush or cleaning web for cleaning the transfer outlet guide member 50, the manufacturing cost can be reduced and the space can be saved.

  Thereafter, when the next print command signal is input, the controller 2 energizes the drive motor 60 again, rotates the transfer outlet guide member 50 at the dropping position toward the guide position, and the transfer outlet guide member 50 guides. When the rotational position detection sensor 61 detects that the position has been reached, the energization to the drive motor 60 is stopped, and the transfer outlet guide member 50 is fixed (held) at the guide position (steps S5 to S8).

  In this way, every time there is a print command signal, the controller 2 automatically removes the foreign matter from the transfer outlet guide member 50 one by one, so that it is possible to efficiently prevent the foreign matter from adhering to the transfer outlet guide member 50. be able to.

  In the present embodiment, the trigger for returning the transfer outlet guide member 50 to the guide position is the input of the image forming command in step S5. Instead, the transfer outlet guide is provided in the control unit 2. A timer for measuring the time after the member 50 reaches the drop position is provided, and the timing can be set as appropriate, for example, when a predetermined time has elapsed.

  Next, other embodiments will be described. In the description, the same components as those described above are denoted by the same reference numerals to simplify the description.

  FIG. 6 is a sectional view schematically showing the image forming unit 1 of the second embodiment according to the present invention. As shown in this figure, the transfer outlet guide member 70 of the transfer device 5 is provided on the plate-like main body 74 and the upper surface of the main body 74 in FIG. A small-size guide plate 71 used, a large-size guide plate 72 provided on the lower surface of the main body 74 in FIG. 6 and used for passing a large-size paper transfer material, and a main body 74. A neutralizing member 73 for neutralizing the transfer material and a rotation shaft 53 integrally provided at the center of both side surfaces of the main body 74 are provided, and the transfer outlet guide member 70 is rotated by the drive motor 60 of the drive unit 57. As a result, the transfer outlet guide member 70 can be rotated 360 °.

  The small-size guide plate 71 is formed in the same shape as the transfer material for small-size paper, and the upper surface in FIG. 6 stands upward from the upper surface, and the transfer direction of the transfer material on the guide plate 71. In FIG. 6, a plurality of ribs 71a extending over the distance are arranged at intervals in the depth direction. The upper surfaces of these ribs 71a are guide surfaces (one guide surface) 71b for guiding a transfer material of small size paper.

  The large-size guide plate 72 is formed in the same shape as the transfer material for large-size paper. Similarly, the large-size guide plate 72 rises downward from the lower surface in FIG. A plurality of ribs 72a extending in the conveying direction of the material are arranged at intervals in the depth direction in FIG. The upper surface of these ribs 72a is a guide surface (the other guide surface) 72b for guiding a large-size paper transfer material.

  The static elimination member 73 is formed in a plate shape from a thin plate such as stainless steel. The downstream portion of the static elimination member 73 in FIG. 6 is lightly bent toward the upper guide surface 71b, and the upstream portion is lightly bent toward the lower guide surface 72b. These tips 73a and 73b are respectively In FIG. 6, peaks and valleys are formed in a saw-tooth shape that is alternately continuous over the depth direction of the paper surface. Further, openings are formed in the portions between the ribs 71a and 72a in the guide plates 71 and 72, and the crests of the tips 73a and 73b of the charge removal member 73 are exposed from these openings, and the transfer is performed. The material can be discharged efficiently.

  In the state shown in FIG. 6, the transfer outlet guide plate 70 is positioned horizontally, and the guide surface 71 b on the small size guide plate 71 side faces upward, so that the transfer size of the small size paper can be guided. The guide surface 72b on the large-size guide plate 72 side faces downward in the opposite direction to the guide surface 71a, and the large-size guide plate 72 removes foreign matter adhering to the guide plate 72. It is a drop position for large size to drop. In this state, when the transfer outlet guide plate 70 is rotated 180 ° about the rotation shaft 53 by driving the drive unit 57, the guide surface 71a on the small size guide plate 71 side faces downward, and the small size guide plate 71 is rotated. Is a small size drop position for dropping the foreign matter adhering to the guide plate 71, and the large size guide plate 72 side guide surface 72a faces upward so that a large size paper transfer material can be guided. The guide surfaces 71b and 72b for guiding the transfer material in the transfer outlet guide member 70 are switched to the size guide position.

  Further, the rotational position detection sensor 61 detects only the state where the transfer outlet guide member 70 is positioned horizontally (the state shown in FIG. 6). In a state where the transfer outlet guide member 70 is positioned horizontally, the rotational position detection sensor 61 detects the transfer outlet guide member 70. When the transfer outlet guide member 70 rotates from this state, the transfer outlet guide member 70 is not detected. Then, when the transfer outlet guide member 70 is rotated 180 ° (a state where the vertical relations of the guide plates 71 and 72 are reversed) and is positioned again horizontally, the rotational position detection sensor 61 detects the transfer outlet guide member 70 again. At this time, the rotational position detection sensor 61 detects that the transfer outlet guide member 70 has rotated 180 °.

  In the control unit 2, when the detection information indicating that the transfer outlet guide member 70 has rotated 180 ° from the state shown in FIG. 6 is received from the rotation position detection sensor 61, the drive of the drive motor 60 is stopped. That is, as drive control of the transfer outlet guide 70 in the present embodiment, when it is detected that the transfer outlet guide member 70 has rotated 180 ° in step S3 of the flowchart shown in FIG. , 72 is different only in that it is determined that the vertical relationship is reversed, and the other control is the same as in FIG.

  As described above, in the present embodiment, the small size guide plate 71 and the large size guide plate 72 are provided on the transfer outlet guide member 70, and the transfer outlet guide member 70 is rotated by 180 ° each time. It is possible to switch to the appropriate guide plates 71 and 72 according to the size of the transfer material to be used. Needless to say, the present embodiment also provides the same operational effects as those of the first embodiment described above.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.

  For example, in the first and second embodiments, the trigger for rotating the transfer outlet guide members 50 and 70 is the end of the image forming operation shown in step S1 of FIG. A counter for counting the number of printed sheets is provided, and when this counter counts a preset set number of sheets, or a reflective optical sensor is provided above the transfer outlet guide members 50 and 70, the transfer outlet guide member 50 The transfer guide members 50 and 70 may be rotated when the reflective optical sensor detects that the amount of accumulated foreign matter has reached a predetermined amount. In these cases, the foreign matter on the transfer outlet guide member 50 can be removed at an appropriate timing when the transfer outlet guide member 50 is contaminated.

  Further, in the first embodiment described above, as an opportunity to rotate the transfer outlet guide member 50 at the guide position toward the drop position, if the large size is printed after the small size printing, the edge surface contamination is likely to occur. From the user's operation to the operation unit 4, a print command signal (image formation command), etc., for example, when A3 vertical feed printing is started after printing a large number of narrow transfer sheets such as A4 vertical feed, etc. When the large size is printed after the small size, the transfer outlet guide may be rotated from the guide position to the drop position before the large size is printed, and the transfer outlet guide 50 is moved to the blocking portion 8a. A cleaning operation of abutment may be performed to effectively prevent edge contamination.

  That is, as drive control of the transfer outlet guide 50 according to this modification, the controller 2 determines that a large transfer material is printed after a small transfer material in step S1 of the flowchart shown in FIG. The other control is the same as in FIG. 5 except that the process proceeds to step S2. The cleaning operation may be completed once, or the transfer outlet guide 50 may reciprocate a plurality of times between the guide position and the drop position.

  In the first and second embodiments described above, the rotation of the transfer outlet guide member 50 is automatically controlled at an appropriate timing by the control unit 2. However, instead of this, the control unit 2 is not provided. In addition, the user may manually rotate the transfer outlet guide member 50 to remove foreign matter from the transfer outlet guide member 50.

  Furthermore, in the second embodiment described above, the transfer outlet guide 70 is rotated 180 ° to reverse the positional relationship between the two guide plates 71 and 72. Instead, the same size transfer material is passed through. In this case, the transfer outlet guide 70 in a horizontal position is rotated clockwise by, for example, 120 ° to drop the foreign matter, and then rotated counterclockwise to return to the original position. May be. Even in this case, the transfer outlet guide 70 can be prevented from being stained, and the transfer material can be prevented from being stained and abnormal images caused by this stain.

1 is a cross-sectional view schematically showing an image forming unit of an image forming apparatus according to a first embodiment of the present invention. FIG. 6 is a cross-sectional view for explaining the operation of a transfer outlet guide member in the transfer apparatus of FIG. 1. It is sectional drawing explaining the transfer operation by the transfer apparatus of FIG. 1 is a block diagram illustrating a configuration of a main part of an image forming apparatus according to a first embodiment of the present invention. It is a flowchart which shows the flow of control by the control part shown in FIG. It is sectional drawing which shows schematically the image formation part of the image forming apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows schematically the image forming part of the conventional image forming apparatus.

Explanation of symbols

2 Control unit 3 Photosensitive drum (image carrier)
DESCRIPTION OF SYMBOLS 5 Transfer apparatus 6 Transfer part 19 Foreign material collection part 19a Foreign material collection port 50, 70 Transfer exit guide member 52 Static elimination member 53 Rotating shaft 55a, 71b, 72b Guide surface 56 Bulkhead sheet (coating member)

Claims (7)

A transfer exit guide having a transfer portion for transferring the toner image on the image carrier to the transfer material while conveying the transfer material, and a guide surface for guiding the transfer material onto which the toner image has been transferred by the transfer portion toward the downstream side In a transfer device comprising a member,
The transfer outlet guide member is rotatable around a rotation axis between a guide position where the guide surface faces upward and guides the transfer material and a fall position where the foreign matter adhering to the guide surface drops away from the guide position. A transfer device provided.   2. A transfer outlet guide member that is provided at a drop position of the transfer outlet guide member and rotates from the guide position toward the drop position, and a blocking portion that blocks the rotation of the transfer outlet guide member. The transfer apparatus according to 1.   There is a foreign matter recovery port formed so as to face the guide surface of the transfer outlet guide member in the dropping position, and a foreign matter recovery part for recovering foreign matter through the foreign matter recovery port and the transfer outlet guide are in the guide position 3. The transfer apparatus according to claim 2, further comprising a covering member that closes the foreign matter collecting port and opens the foreign matter collecting port when the transfer outlet guide is in the dropping position.   A pair of guide surfaces of the transfer outlet guide member is provided, and when one guide surface is directed upward to guide the transfer material, the other guide surface is directed downward, and the transfer outlet guide member rotates. The transfer apparatus according to claim 1, wherein the direction of one guide surface and the direction of the other guide surface are interchanged.   The transfer apparatus according to claim 1, wherein the transfer outlet guide member is provided with a charge removal member for removing charge from the transfer material.   A drive unit that is connected to the rotation shaft to drive the rotation shaft, a position detection unit that detects whether the transfer outlet guide member is located at the guide position or the drop position, and detection information of the position detection unit 6. The transfer according to claim 1, further comprising a control unit that drives the drive unit so that the transfer outlet guide member is positioned at either the guide position or the drop position. apparatus. In an image forming apparatus for forming an image on a transfer material by an image carrier on which a toner image is formed,
An image forming apparatus comprising the transfer device according to claim 1.

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