JP2006193328A - Paper guide device and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly guide paper at a position where two paper carrying passages are converged with each other by preventing the paper from reversely flowing in an unintended direction by a simple structure. <P>SOLUTION: This paper guide device 40 is disposed at the position where a paper carrying passage 50 for discharge as the first paper carrying passage is converged with a paper carrying passage 60 for double-sided printing as the second paper carrying passage. An actuator 71 of a paper detection means 70 is installed in a right side guide 51 constituting the paper carrying passage 50 for discharge at a position on the upstream side of the converged position in the paper carrying direction, and always holds a second attitude for guiding the paper P passed through the paper carrying passage 60 for double-sided printing by an energizing means. The actuator 71 comprises a paper guide part 71c guiding the paper P passed through the paper carrying passage 60 for double-sided printing. When it takes a second attitude, the surface of the paper guide part 71c is projected inward from the surface of a lower guide 61a forming the paper carrying passage 60 for double-sided printing present on the immediate downstream side of the paper guide part 71c. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper guide device such as a cut paper, which can be applied to an image forming apparatus represented by a copying machine or a printer. The present invention also relates to an image forming apparatus equipped with this paper guide device.

  In an image forming apparatus such as a copying machine or a printer, components such as a sheet feeding unit, a transfer unit, a fixing unit, and a sheet reversing unit for duplex printing are arranged, and a sheet conveyance path is formed between them. ing. In such an image forming apparatus, there is an image forming apparatus that employs a switchback method in the sheet reversing unit to switch the sheet conveyance direction. The sheet reversing unit is configured such that the sheet conveying path leading to the sheet reversing unit joins the sheet conveying path continuing from the sheet reversing unit.

  Here, at the location where the two paper transport paths merge, it is necessary to prevent the paper from flowing back when the paper is switched back to the paper transport path through which the paper has entered when entering the merge location. An example of a sheet guide device in which a backflow prevention device is devised for such a joining point can be seen in Patent Document 1. In the double-sided recording device (paper guide device) described in Patent Document 1, the double-sided recording path leading to the switchback unit is joined to the refeeding path that continues from the switchback position, and the double-sided recording at the junction is performed. A film-like elastic member is provided at the exit of the road to prevent backflow. However, when the film-like elastic member prevents backflow of the paper, the elastic member is relatively long in the paper width direction perpendicular to the paper conveyance direction so that the elastic member does not lose the strength of the paper. Must be used. As a result, the elastic member comes into contact over a wide area of the paper, and there is a possibility that the paper may be damaged by friction or an image defect may occur.

On the other hand, the paper transport path may be provided with a paper detection means for detecting the presence of paper passing through the paper transport path. Upon receiving information from the paper detection means, the image forming apparatus measures the timing of the image forming operation or recognizes that a paper jam has occurred. A paper guide device is proposed in which this paper detection means is provided at a location where two paper transport paths merge to detect paper in one of the paper transport paths and is used as a countermeasure for backflow of paper. It can be seen in Patent Document 2.
JP 2003-312915 A (page 3-5, FIG. 2) JP 2004-35135 A (page 6-8, FIG. 5)

  In the paper reversing device (paper guide device) described in Patent Document 2, the front shape perpendicular to the paper conveyance direction between the entrance path and the discharge path with respect to the paper reversing section is switched to the tip of the wedge-shaped area. A member (detection member) is provided. However, since the rotation shaft portion of the switching member is exposed in the paper transport path, there is a concern that the switching member may be unintentionally displaced due to contact with or friction with the paper being transported. Is given. Thereby, there exists a possibility that the structure of a switching member and its periphery may become very complicated.

  The present invention has been made in view of the above points, and in an unintended direction by a simple structure using a sheet detection unit that detects the presence of a sheet on a sheet conveyance path at a position where two sheet conveyance paths meet. An object of the present invention is to provide a paper guide device that can prevent the paper from flowing backward and can smoothly guide the paper. It is another object of the present invention to provide a highly reliable image forming apparatus equipped with such a sheet guide device.

  In order to solve the above-described problem, the present invention detects the presence of a sheet passing through the first sheet conveyance path in the vicinity of a location where the first sheet conveyance path merges with the second sheet conveyance path. And a sheet guide device provided with a sheet detecting means provided with an actuator capable of taking both positions of the second position for guiding the sheet passing through the second sheet conveyance path, A sheet guide portion for guiding a sheet passing through the second sheet conveyance path; and a guide member constituting the first sheet conveyance path, provided at a position upstream of the merging position in the sheet conveyance direction, and an actuator When the second posture is taken, only the sheet guide portion protrudes inward from the guide member on the downstream side in the sheet conveyance direction of the sheet guide portion, which constitutes the second sheet conveyance path. Paper passing through It was decided to guide you.

  Further, the actuator has a U-shaped front shape that is perpendicular to the paper transport direction, and rotates about a shaft portion provided at one end of the actuator, whereby both the first and second modes are used. It can take a posture, and is provided with a paper contact portion where the paper passing through the first paper transport path comes into contact with a substantially central portion thereof, and the paper guide portion around the other end.

  Further, the actuator always holds the second posture for guiding the paper passing through the second paper transport path by the biasing means, and transports the paper through the first paper transport path. Sometimes, the conveyed paper abuts against the actuator, so that the posture is changed to the first posture for detecting the presence of the paper passing through the first paper conveyance path against the urging force of the urging means. It was.

  Further, a rotation member is provided on a guide member on the first paper transport path side that is immediately downstream of the actuator in the paper transport direction with respect to the first paper transport path and that constitutes the second paper transport path did.

  The rotating member is rotated according to the movement of the paper.

  Also, between the first paper transport path and the second paper transport path, in the vicinity of the junction, both an open posture for opening the first paper transport path and a closed posture for closing are used. A claw member that can take a posture and always maintains a closed posture is provided.

  Further, a movable guide is provided between the first sheet conveyance path and the second sheet conveyance path, and the claw member is provided at a portion of the guide rib provided on the movable guide on the side of the joining point. did.

  In addition, the claw member always maintains a closed posture with the weight of the claw member itself.

  In the present invention, the paper guide device is mounted on the image forming apparatus.

  According to the configuration of the present invention, in the sheet guide device including the sheet detection unit in which the actuator is provided in the vicinity of the portion where the first sheet conveyance path joins the second sheet conveyance path, A sheet guide portion for guiding the sheet passing through the sheet conveyance path is provided, and the guide member constituting the first sheet conveyance path is provided at a position upstream of the merging position in the sheet conveyance direction, and the actuator has the second posture. When taking the sheet, only the sheet guide unit guides the sheet passing through the second sheet conveyance path so as to protrude inward from the guide member on the downstream side in the sheet conveyance direction of the sheet guide unit constituting the second sheet conveyance path. Therefore, the actuator can perform the sheet detection in the first sheet conveyance path and the sheet guidance in the second sheet conveyance path by reducing the range in contact with the sheet as much as possible. That. As a result, it is possible to prevent the backflow of the paper to the second paper transport path without causing paper breakage or image failure. In addition, since the actuator is provided in the first paper transport path and only the paper guide portion is exposed in the paper transport space of the second paper transport path, it can be unintentionally displaced by contact with the paper or friction. It can be suppressed as much as possible, and the sheet can be prevented from being caught by the guide member of the second sheet conveyance path. For these reasons, it is possible to smoothly guide the paper by preventing the backflow of the paper in an unintended direction by a simple structure using the paper detection means for detecting the presence of the paper in the paper conveyance path. .

  The actuator has a U-shaped front shape that is perpendicular to the paper transport direction, and rotates around a shaft provided at one end of the actuator, so that both the first and second postures are achieved. Since the paper abutting portion where the paper passing through the first paper conveyance path abuts is provided at the substantially central portion thereof, and the paper guide portion is provided around the other front end, the actuator is provided with the first In the sheet conveyance path, the sheet is provided on the upstream side in the sheet conveyance direction from the junction, and the sheet passing through the second sheet conveyance path can be smoothly flowed by the sheet guide unit.

  Further, the actuator always holds the second posture for guiding the paper passing through the second paper transport path by the urging means. When the paper is transported through the first paper transport path, the actuator transports the actuator. Since the paper to be contacted with the actuator, the posture is changed to the first posture for detecting the presence of the paper passing through the first paper conveyance path against the urging force by the urging means. The actuator can be displaced to the first posture only when the sheet passes through the first sheet conveyance path by utilizing the propulsive force of the conveyed sheet. Then, after the sheet passes through the first sheet conveyance path, the actuator can be automatically displaced to the second posture. Accordingly, it is possible to stably transport the paper at any point where the two paper transport paths meet, regardless of which paper transport path passes through the paper.

  In addition, since the guide member on the first paper conveyance path side that constitutes the second paper conveyance path, immediately downstream of the actuator in the paper conveyance direction with respect to the first paper conveyance path, is provided with a rotating member. The rotating member can prevent the paper passing through the second paper transport path from proceeding in the direction of the first paper transport path. Thereby, the effect | action which prevents the backflow to the 1st paper conveyance path of the paper which passes a 2nd paper conveyance path is heightened, and it becomes possible to guide a paper more smoothly. Further, since it is a rotating member, it does not damage the paper or cause image defects.

  Further, since the rotating member is rotated in accordance with the movement of the paper, it does not hinder the flow of the paper or impose a load on the paper. Thereby, the effect | action for guiding a paper more smoothly improves. Further, since a driving means for the rotating member is not required, a significant increase in cost can be suppressed.

  In addition, between the first paper transport path and the second paper transport path, in the vicinity of the joining point, both an open posture for opening the first paper transport path and a closed posture for closing are taken. In addition, since the claw member that always holds the closed posture is provided, the claw member can prevent the sheet from entering the first sheet conveyance path from the second sheet conveyance path. Thereby, the effect | action which prevents the backflow of the paper to the direction which is not intended is heightened, and it becomes possible to guide a paper more smoothly.

  In addition, since the movable guide is provided between the first paper conveyance path and the second paper conveyance path, and the claw member is provided in the portion of the guide rib provided on the movable guide on the side of the merge point, Even in a model having a movable guide at a location, it is possible to enhance the effect of preventing the backflow of the paper in an unintended direction. Therefore, the range of models capable of smoothly guiding paper is widened, which is very convenient.

  In addition, since the claw member is always kept in the closed posture by the weight of the claw member itself, the claw member can be automatically displaced to the closed posture without using a drive device such as a solenoid or a motor. Can do. Therefore, it is possible to obtain a structure capable of enhancing the effect of preventing the reverse flow of the paper in an unintended direction at a low cost.

  Further, in the present invention, since the paper guide device is mounted on the image forming apparatus, it is easy to use a paper detection unit that detects the presence of the paper in the paper transport path at a location where the two paper transport paths meet. With this structure, it is possible to obtain a highly reliable image forming apparatus that can prevent paper backflow in an unintended direction and can smoothly guide the paper.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an image output operation of an image forming apparatus equipped with a paper guide apparatus according to an embodiment of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. Note that solid line arrows in the figure indicate the sheet conveyance path and conveyance direction, and alternate long and short dash line arrows indicate the laser beam L.

  In FIG. 1, a paper feeding unit 3 is disposed at the lower part of the main body 2 of the image forming apparatus 1. Inside the paper feed unit 3, paper P such as cut paper before printing is stacked and stored, and the paper P is separated and sent out one by one.

  A paper transport unit 4 is provided inside the main body 2 and on the left side of the paper feed unit 3. The paper P sent out from the paper supply unit 3 is conveyed vertically upward along the side surface of the main body 2 by the paper conveyance unit 4 and reaches a transfer unit 9 described later.

  On the other hand, a document feeding unit 5 is provided on the upper surface of the image forming apparatus 1, and a document image reading unit 6 is provided below the document feeding unit 5. When a user copies a document, a document on which an image such as a character, a figure, or a pattern is drawn is stacked on the document feeding unit 5. The document feeding unit 5 separates the documents one by one and sends the document, and the document image reading unit 6 reads the image data. The information of the image data is sent to the laser irradiation unit 7 disposed above the paper feed unit 3 and in the center of the main body 2. The laser beam L controlled based on the image data is irradiated by the laser irradiation unit 7 toward the image forming unit 8 described later.

  An image forming unit 8 and a transfer unit 9 are provided above the paper transport unit 4 and to the left of the laser irradiation unit 7. In the image forming unit 8, an electrostatic latent image of a document image is created by the laser light L emitted by the laser irradiation unit 7. A toner image is formed from the electrostatic latent image, and the toner image is transferred by the transfer unit 9 onto the pre-printing paper P sent in synchronization by the paper transport unit 4.

  A fixing unit 10 is provided above the transfer unit 9. The paper P carrying the unfixed toner image in the transfer unit 9 is sent to the fixing unit 10 where the toner image is heated and fixed by the fixing roller.

  A branch unit 20 is provided above the fixing unit 10. The sheet P discharged from the fixing unit 10 is discharged from the branching unit 20 to a sheet discharge tray 11 provided in the cylinder of the image forming apparatus 1 when double-sided printing is not performed.

  The discharge port portion from which the paper P is discharged from the branch unit 20 toward the paper discharge tray 11 functions as the switchback unit 30. When performing duplex printing, the switchback unit 30 switches the transport direction of the paper P discharged from the fixing unit 10. Then, the paper P is sent downward through the left side of the fixing unit 10 and the left side of the transfer unit 9, and is sent again to the transfer unit 9 through the paper transport unit 4.

  In such a branching unit 20, the sheet P discharged from the fixing unit 10 is conveyed toward the sheet discharge tray 11, or the sheet P whose conveyance direction is switched by the switchback unit 30 is again directed toward the transfer unit 9. The paper guide device 40 of the present invention is provided at a place where the paper is conveyed.

  Next, a detailed configuration around the sheet guide device 40 according to the first embodiment of the present invention will be described with reference to FIG. 2 in addition to FIG. FIG. 2 is a partially enlarged schematic vertical sectional view showing the periphery of the sheet guide device. In FIG. 2, the solid line arrows indicate the sheet conveyance path and the conveyance direction.

  As shown in FIG. 2, the paper guide device 40 is provided in the branching unit 20, and a discharge paper transport path 50 that is a first paper transport path is a double-sided printing paper transport path that is a second paper transport path. It is arranged at a location where it merges with 60. The paper guide device 40 includes paper detection means 70.

  The paper detection means 70 is provided with an actuator 71. The actuator 71 is provided at a location on the upstream side in the paper transport direction of the right guide 51 that is a guide member constituting the paper transport path 50 for discharge from the junction of the paper transport path 50 for discharge and the paper transport path 60 for duplex printing. It has been. One actuator 71 is provided at a substantially central portion of the discharge paper transport path 50 in the paper width direction perpendicular to the paper transport direction (see FIG. 4).

  The actuator 71 is supported so as to be rotatable around a shaft portion 71a provided at one end of the front surface, which is perpendicular to the sheet conveyance direction. The actuator 71 rotates in a vertical plane about the shaft portion 71a, thereby detecting the presence of the sheet P passing through the discharge sheet transport path 50, which is the first sheet transport path, and the second posture. It is possible to change the posture in the same manner as the second posture for guiding the paper P passing through the double-sided printing paper conveyance path 60, which is the paper conveyance path.

  A torsion spring (not shown) which is an urging means is provided at a position of the shaft portion 71 a of the actuator 71. As a result, the actuator 71 is urged to rotate counterclockwise in FIG. The actuator 71 does not rotate counterclockwise beyond the position shown in FIG. 2 by the action of a stopper (not shown), and always guides the paper P passing through the double-sided printing paper conveyance path 60. Holds posture. Note that the torsion spring has a resilient force that does not hinder the actuator 71 from rotating clockwise by the contact of the paper P.

  A substantially a central portion of the U-shaped actuator 71 is provided with a paper contact portion 71b on which the paper P passing through the discharge paper transport path 50 contacts. When the paper P sent out from the fixing unit 10 comes into contact with the paper contact portion 71b, the actuator 71 is rotated in the clockwise direction in FIG. 2 to detect the presence of the paper P passing through the discharge paper transport path 50. The posture is changed to the first posture (one-dot chain line in FIG. 2).

  A paper guide portion 71c for guiding the paper P passing through the double-sided printing paper conveyance path 60 is provided around the tip of the actuator 71 opposite to the shaft portion 71a. When the actuator 71 takes the second position shown in FIG. 2, the surface of the paper guide portion 71c is a guide member that forms the double-sided printing paper conveyance path 60, and is immediately downstream of the paper guide portion 71c. It projects inward from the surface of the existing lower guide 61a.

  The paper detection means 70 is provided with an optical sensor (not shown) such as a photo interrupter in order to grasp the operation of the actuator 71.

  A discharge paper transport path 50 that is a first paper transport path is provided downstream of the fixing unit 10 in the paper transport direction. The paper P discharged from the fixing unit 10 by the transport roller 53 reaches the location of the paper guide device 40 through the paper transport space between the right guide 51 and the left guide 52 constituting the discharge paper transport path 50. To do.

  A double-sided printing paper conveyance path 60 as a second paper conveyance path extends downward from the switchback unit 30 to the left of the fixing unit 10 and the left of the transfer unit 9, and below the transfer unit 9. Is joined to the paper transport unit 4 (see FIG. 1). The double-sided printing paper conveyance path 60 includes a plurality of guide members such as a lower guide 61 a and an upper guide 62, and a plurality of conveyance rollers 63.

  The switchback unit 30 includes a discharge roller 31 and a discharge port 32. The discharge roller 31 includes a pair of rollers that are in contact with each other, and is provided near the discharge port 32 through which the paper P is discharged toward the paper discharge tray 11 (see FIG. 1). The paper P is inserted into a nip formed by contact with a pair of rollers constituting the discharge roller 31, and is sent out to the paper discharge tray 11 by rotating the discharge roller 31. When performing duplex printing, when the discharge roller 31 holds the upstream end of the paper P, the conveyance direction of the paper P is switched by reversing the rotation of the discharge roller 31. The discharge roller 31 is rotated by driving means (not shown).

  Next, the guidance operation of the paper P by the paper guidance device 40 will be described with reference to FIGS. 1 and 2.

  In the image forming apparatus 1, the actuator 71 of the paper detection unit 70 provided in the paper guide device 40 always takes the second posture shown in FIG. 2 by the action of a torsion spring (not shown) that is a biasing unit. I'm taking it. Here, when the image output operation is executed and the paper P is transported toward the paper discharge tray 11, the paper P is lowered to the paper transport space between the right guide 51 and the left guide 52 of the discharge paper transport path 50. Enter from.

  Subsequently, the conveyance of the paper P proceeds, and the paper P comes into contact with the paper contact portion 71 b of the actuator 71. As a result, the actuator 71 resists the elastic force of the torsion spring, which is the biasing means, and passes through the discharge paper transport path 50, which is the first paper transport path, as shown by the one-dot chain line in FIG. The posture is changed to the first posture for detecting the presence of P.

  When the conveyance of the paper P further proceeds, the paper P is inserted into the nip of the discharge roller 31 and sent out toward the paper discharge tray 11. When the paper P moves away from the actuator 71, the actuator 71 takes a second posture to guide the paper P passing through the double-sided printing paper conveyance path 60, which is the second paper conveyance path, by the elastic force of the torsion spring. You can change your posture. When the actuator 71 takes the second posture, the surface of the sheet guide portion 71c is located on the inner side of the surface of the lower guide 61a of the sheet conveying path 60 for double-sided printing, which is present immediately downstream of the sheet guide portion 71c. Since it protrudes, even if the switchback operation is immediately executed as it is and the transport direction of the paper P is switched, the upstream end of the paper P is not caught by the front end of the lower guide 61a.

  In this way, the paper detection in which the actuator 71 is provided in the vicinity of the portion where the discharge paper transport path 50 as the first paper transport path joins the double-sided printing paper transport path 60 as the second paper transport path. In the paper guide device 40 provided with the means 70, the actuator 71 is a guide member that includes a paper guide portion 71 c that guides the paper P passing through the paper transport path 60 for double-sided printing and that constitutes the paper transport path 50 for discharge. A sheet guide provided on the right guide 51 at a position upstream of the joining position in the sheet conveying direction, and when the actuator 71 takes the second posture, only the sheet guiding portion 71c constitutes the sheet conveying path 60 for double-sided printing. Guides the paper P that protrudes inward from the lower guide 61a that is a guide member immediately downstream in the paper conveyance direction of the section 71c and passes through the paper conveyance path 60 for double-sided printing. , By an actuator 71, and minimize the extent of contact with the sheet P, a sheet detection in discharging the sheet conveying path 50, it is possible to perform the sheet guide in the double-sided printing paper transport path 60. Thus, the backflow of the paper P to the double-sided printing paper conveyance path 60 can be prevented without causing damage to the paper P or image defects. The actuator 71 is provided in the discharge paper transport path 50, and only the paper guide portion 71c is exposed in the paper transport space of the double-sided printing paper transport path 60. Therefore, the actuator 71 is unintentionally displaced by contact with the paper P or friction. The sheet P can be suppressed as much as possible, and the sheet P can be prevented from being caught by the lower guide 61a of the sheet conveying path 60 for double-sided printing. For these reasons, the simple structure using the paper detection means 70 for detecting the presence of the paper P in the paper transport path prevents the paper P from flowing back in an unintended direction and smoothly guides the paper P. Is possible.

  Further, the actuator 71 has a U-shaped front shape that is perpendicular to the paper transport direction, and rotates about a shaft portion 71a provided at one end of the actuator 71, whereby both the first and second modes are provided. Since the sheet abutting portion 71b with which the sheet P passing through the discharge sheet conveyance path 50 abuts and the sheet guiding portion 71c around the other end are provided at the substantially central portion thereof, the actuator 71 is provided. In the discharge paper conveyance path 50, the paper P is provided on the upstream side in the paper conveyance direction from the junction, and the paper P passing through the double-sided printing paper conveyance path 60 can be smoothly flowed by the paper guide portion 71 c.

  The actuator 71 maintains the second posture for always guiding the paper P passing through the double-sided printing paper conveyance path 60 by the urging means, and conveys the paper P through the discharge paper conveyance path 50. When the paper P to be conveyed contacts the actuator 71, the posture is changed to the first posture that detects the presence of the paper P passing through the discharge paper conveyance path 50 against the urging force of the urging means. Therefore, the actuator 71 can be displaced to the first posture only when the paper P passes the discharge paper transport path 50 by using the propulsive force of the transported paper P. Then, after the paper P passes the discharge paper transport path 50, the actuator 71 can be automatically displaced to the second posture. Therefore, even when the paper P passes through any of the paper transport paths at the location where the two paper transport paths meet, the paper P can be transported stably.

  Further, in the present invention, since the sheet guide device 40 is mounted on the image forming apparatus 1, a simple sheet detection unit that detects the presence of the sheet P in the sheet conveyance path at a location where the two sheet conveyance paths meet. With this structure, it is possible to obtain a highly reliable image forming apparatus 1 that can prevent the backflow of the paper P in an unintended direction and can smoothly guide the paper P.

  Next, a detailed configuration around the sheet guide device 40 according to the second embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a partially enlarged schematic vertical section showing the periphery of the sheet guide device. FIG. 4 is a schematic partial enlarged left side view showing the periphery of the actuator and the conveyance roller. Since the basic configuration of this embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, the same reference numerals are assigned to the same components as those of the first embodiment. The description will be omitted.

  As shown in FIGS. 3 and 4, in the second embodiment, the paper guide device 40 includes a conveyance roller 41 that is a rotating member. The conveyance roller 41 is disposed immediately downstream of the actuator 71 in the sheet conveyance direction with respect to the discharge sheet conveyance path 50 that is the first sheet conveyance path. The transport roller 41 is provided in a lower guide 61b, which is a guide member on the discharge paper transport path 50 side, which constitutes a double-sided printing paper transport path 60 that is a second paper transport path. The transport roller 41 includes four roller portions 41a in the paper width direction (see FIG. 4), and a part of the roller portion 41a is exposed in the paper transport space of the double-sided printing paper transport path 60 (FIG. 3). reference). In addition, the roller part 41a of the conveyance roller 41 is not limited to four pieces, A small number or many may be sufficient as this. The drive roller 41 is not connected to the transport roller 41 and rotates according to the movement of the paper P by the frictional force with the paper P moving on the double-sided printing paper transport path 60.

  Thus, the double-sided printing paper conveyance path 60, which is the second paper conveyance path, is located immediately downstream of the actuator 71 in the paper conveyance direction with respect to the discharge paper conveyance path 50, which is the first paper conveyance path. Since the lower guide 61b, which is a guide member on the discharge paper conveyance path 50 side, is provided with a conveyance roller 41 that is a rotating member, the paper P that passes through the double-sided printing paper conveyance path 60 is discharged by the conveyance roller 41. Proceeding in the direction of the conveyance path 50 can be prevented. As a result, the action of preventing the reverse flow of the paper P passing through the double-sided printing paper conveyance path 60 to the discharge paper conveyance path 50 is enhanced, and the paper P can be guided more smoothly. Further, since the transport roller 41 is a rotating member, the paper P is not damaged and an image defect is not generated.

  Further, since the transport roller 41 rotates in accordance with the movement of the paper P, it does not hinder the flow of the paper P or impose a load on the paper P. Thereby, the effect | action for guiding the paper P more smoothly improves. Moreover, since the drive means of the conveyance roller 41 is not required, a significant cost increase can be suppressed.

  Next, a detailed configuration around the sheet guide device 40 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic vertical sectional partial enlarged view showing the periphery of the sheet guide device. Since the basic configuration of this embodiment is the same as that of the first and second embodiments, the same components as those of the first embodiment are denoted by the same reference numerals as those of the previous embodiment, and description thereof is omitted. Shall.

  As shown in FIG. 5, in the third embodiment, a movable guide 80 is provided between the discharge paper conveyance path 50 and the double-sided printing paper conveyance path 60 that join together. The movable guide 80 has substantially the same length in the paper width direction as the discharge paper conveyance path 50 and the double-sided printing paper conveyance path 60. The movable guide 80 includes a support shaft 80a extending in the paper width direction and rotating to the main body 2 by the support shaft 80a in order to make it easier to sort the paper P. It is supported freely. The movable guide 80 rotates in a vertical plane around the support shaft 80a to assist the conveyance of the sheet P passing through the two sheet conveyance paths (solid line in FIG. 5), and the switchback unit. The posture can be changed from the posture (two-dot chain line in FIG. 5) for transporting the paper P from the discharge paper transport path 50 to the double-sided printing paper transport path 60 without going through 30.

  As described above, even when a part of the guide members constituting the discharge paper conveyance path 50 and the double-sided printing paper conveyance path 60 is replaced with the movable guide 80, the same as in the first embodiment. Actions and effects can be obtained. Also for this third embodiment, it is possible to provide the transport roller 41 shown in the second embodiment, and thereby, as in the second embodiment, a paper transport path for double-sided printing. The action of preventing the reverse flow of the paper P passing through the paper 60 to the discharge paper conveyance path 50 is enhanced, and the paper P can be guided more smoothly.

  Next, a detailed configuration around the sheet guide device 40 according to the fourth embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a partially enlarged schematic vertical section showing the periphery of the sheet guide device. FIG. 7 is a model partially enlarged top view showing the actuator, the conveying roller, and the periphery of the claw member, FIG. 8 is a model front view of the claw member, FIG. 9 is a model front view showing how to attach the claw member, and FIG. FIG. 7 is a model vertical cross-sectional partial enlarged view showing the periphery of the sheet guide device similar to FIG. 6, and shows a state when the sheet passes through the discharge sheet conveyance path. Since the basic configuration of this embodiment is the same as that of the first and second embodiments, the same components as those of the first embodiment are denoted by the same reference numerals as those of the previous embodiment, and description thereof is omitted. Shall.

  As shown in FIG. 6, in the fourth embodiment, a claw member 90 is provided between the discharge paper conveyance path 50 and the double-sided printing paper conveyance path 60 to be merged and in the vicinity of the merge point. Yes. As shown in FIG. 7, the claw member 90 includes a plurality of claw members 90 between the roller portion 41 a of the conveyance roller 41 and the actuator 71 and between the adjacent roller portions 41 a in the paper width direction of the double-sided printing paper conveyance path 60. Is provided.

  As shown in FIGS. 8 and 9, the claw member 90 has a wedge-shaped front surface perpendicular to the paper transport direction and a support shaft 90a extending in the paper width direction so as to easily distribute the paper P. I have. The claw member 90 is rotatably supported by a bearing 64 provided at a position where the left guide 52 of the discharge paper conveyance path 50 and the lower guide 61a of the double-sided printing paper conveyance path 60 meet by the support shaft 90a. Has been. A locking piece 91 is provided at a position on the opposite side of the support shaft 90a with respect to the tip of the wedge of the claw member 90. On the other hand, in the lower guide 61a, an engagement recess 65 is provided at a location corresponding to the locking piece 91 of the claw member 90. As shown in FIG. 8, when the claw member 90 is attached to the bearing 64 of the lower guide 61 a, the locking piece 91 is stored in the engaging recess 65. And since the movement range of the locking piece 91 is regulated by the engaging recess 65, the rotation angle of the claw member 90 is limited.

  The claw member 90 rotates in a vertical plane around the support shaft 90a to close the discharge paper conveyance path 50 (see FIG. 6) and the open attitude to open the discharge paper conveyance path 50 (see FIG. 6). (See FIG. 10). Regarding the rotational displacement of the claw member 90, the driving means is not connected to the claw member 90. When the paper P does not pass through the discharge paper transport path 50, the claw member 90 is subjected to a moment that tends to be displaced in the closing direction due to its own weight, and is displaced to the closed posture shown in FIG. As long as the paper P does not pass through the discharge paper transport path 50, the claw member 90 always maintains the closed posture. On the other hand, when the paper P passes through the discharge paper conveyance path 50, the claw member 90 is pushed up by the paper P, rotates around the support shaft 90a, and is displaced to the open posture shown in FIG. At this time, the actuator 71 is changed in posture to the first posture for detecting the presence of the paper P passing through the discharge paper conveyance path 50 against the resilient force of the torsion spring as the biasing means.

  In this way, between the discharge paper conveyance path 50 and the double-sided printing paper conveyance path 60 and in the vicinity of the junction, both the open posture for opening the discharge paper conveyance passage 50 and the closed posture for closing it are provided. And the claw member 90 that always keeps the closed posture is provided, so that the paper P enters the discharge paper conveyance path 50 from the double-sided printing paper conveyance path 60 by the claw member 90. I can stop. Thereby, the effect | action which prevents the back flow of the paper P to an unintended direction is heightened, and it becomes possible to guide the paper P more smoothly.

  Further, since the claw member 90 always maintains the closed posture with the weight of the claw member 90 itself, the claw member 90 is automatically displaced to the closed posture without using a drive device such as a solenoid or a motor. Can do. Therefore, a structure capable of enhancing the effect of preventing the backflow of the paper P in an unintended direction can be obtained at a low cost.

  Next, a detailed configuration around the sheet guide device 40 according to the fifth exemplary embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a partially enlarged schematic vertical section showing the periphery of the sheet guide device. FIG. 12 is a model partial enlarged top view showing the periphery of the actuator, the conveyance roller, and the movable guide, FIG. 13 is a model front view of the guide rib of the movable guide, and FIG. 14 is a model showing the periphery of the sheet guide device similar to FIG. FIG. 15 is a schematic enlarged vertical sectional view showing the periphery of the paper guiding device similar to FIG. 11, and shows the state when the paper passes through the discharge paper transport path. 4 shows a state when the paper passes through the paper transport path for double-sided printing without passing through the section. Since the basic configuration of this embodiment is the same as that of the first to fourth embodiments, the same components as those of the embodiments are denoted by the same reference numerals as those of the previous embodiment, and the description thereof is omitted. And

  As shown in FIG. 11, in the fifth embodiment, a movable guide 100 is provided between a discharge paper conveyance path 50 and a double-sided printing paper conveyance path 60 that join together. As shown in FIG. 12, the movable guide 100 includes a plurality of movable guides 41 between the roller portions 41a of the transport rollers 41 and the actuators 71 and between the adjacent roller portions 41a in the paper width direction of the double-sided printing paper transport path 60. A guide rib 101 is provided. The plurality of guide ribs 101 are connected by a common support shaft 102 extending in the paper width direction. The guide rib 101 has a flat plate shape extending in the paper transport direction, and guides the paper P in contact with the paper surface of the paper on the transport path at a substantially right angle. And as shown in FIG. 13, the claw member 90 is rotatably provided in the bearing 103 provided in the part by the side of the confluence | merging location of each guide rib 101. As shown in FIG. On the other hand, in each guide rib 101, an engagement recess 104 in which the locking piece 91 is accommodated when the claw member 90 is attached to the guide rib 101 is provided at a position corresponding to the locking piece 91 of the claw member 90.

  The claw member 90 rotates in a vertical plane around the support shaft 90a to close the discharge paper conveyance path 50 (see FIG. 11) and the open attitude to open the discharge paper conveyance path 50 (see FIG. 11). (See FIG. 14). The claw member 90 always maintains a closed posture by its own weight, and when the paper P passes through the discharge paper conveyance path 50, the leading end thereof is pushed up by the paper P and is displaced to the open posture.

  In addition, the movable guide 100 rotates in a vertical plane around the support shaft 102 to assist the conveyance of the paper P through the discharge paper conveyance path 50 and the duplex printing paper conveyance path 60 ( 11 and FIG. 14) and the posture (see FIG. 15) for transporting the paper P from the discharge paper transport path 50 to the double-sided printing paper transport path 60 without passing through the switchback unit 30. It can be changed.

  Thus, the movable guide 100 is provided between the discharge paper conveyance path 50 and the double-sided printing paper conveyance path 60, and the claw member 90 is provided in the portion of the movable guide 100 on the merging location side. Even in a model provided with the movable guide 100 at a location, it is possible to enhance the effect of preventing the backflow of the paper P in an unintended direction. Therefore, the range of models that can smoothly guide the paper P is widened, which is very convenient.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in a sheet guide device provided with a place where two sheet conveyance paths meet.

1 is a schematic vertical sectional front view of an image forming apparatus equipped with a paper guide device according to an embodiment of the present invention. FIG. 3 is a partially enlarged schematic vertical cross-sectional view showing the periphery of the sheet guide device according to the first embodiment of the present invention. It is a model vertical cross-section part enlarged view which shows the paper guide apparatus periphery which concerns on the 2nd Embodiment of this invention. FIG. 4 is a schematic partial enlarged left side view showing the actuator and the periphery of a conveyance roller in FIG. 3. It is a model vertical cross-section part enlarged view which shows the paper guide apparatus periphery which concerns on the 3rd Embodiment of this invention. It is a model vertical cross-section part enlarged view which shows the paper guide apparatus periphery which concerns on the 4th Embodiment of this invention. It is a model partial enlarged top view which shows the actuator of FIG. 6, a conveyance roller, and a claw member periphery. It is a model front view of the nail | claw member of FIG. It is a model front view which shows the attachment method of the nail | claw member of FIG. FIG. 7 is a model vertical cross-sectional partial enlarged view showing the periphery of the sheet guide device similar to FIG. 6, and shows a state when the sheet passes through the discharge sheet conveyance path. It is a model vertical cross-section part enlarged view which shows the paper guide apparatus periphery which concerns on the 5th Embodiment of this invention. It is a model partial enlarged top view which shows the actuator of FIG. 11, a conveyance roller, and a movable guide periphery. It is a model front view of the guide rib of the movable guide of FIG. FIG. 12 is a partially enlarged schematic vertical sectional view showing the periphery of the sheet guide device similar to FIG. 11 and shows a state when the sheet passes through the discharge sheet conveyance path. FIG. 12 is a partially enlarged schematic vertical sectional view showing the periphery of the sheet guide device similar to FIG. 11, and shows a state when the sheet passes through the double-sided printing sheet conveyance path without passing through the switchback unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Fixing part 20 Branching part 30 Switchback part 40 Paper guide apparatus 41 Conveyance roller (rotating member)
41a Roller part 50 discharge paper transport path (first paper transport path)
51 Right side guide (guide member)
60 Double-sided printing paper transport path (second paper transport path)
61 Lower guide (guide member)
DESCRIPTION OF SYMBOLS 70 Paper detection means 71 Actuator 71a Support shaft 71b Paper contact part 71c Paper guide part 80 Movable guide (guide member)
90 claw member 90a support shaft 100 movable guide (guide member)
101 Guide rib 102 Spindle

Claims (9)

In the vicinity of the location where the first paper transport path joins the second paper transport path, the first posture for detecting the presence of the paper passing through the first paper transport path and the second paper transport path In a paper guide device provided with a paper detection means provided with an actuator capable of taking both postures of the second posture for guiding the passing paper,
The actuator includes a sheet guide portion that guides a sheet passing through the second sheet conveyance path, and a guide member that configures the first sheet conveyance path at a position upstream of the merging position in the sheet conveyance direction. When the actuator is in the second posture, only the sheet guide portion protrudes inward from the guide member that forms the second sheet conveyance path and is immediately downstream of the sheet conveyance direction of the sheet guide portion. A paper guide device for guiding paper passing through two paper transport paths.   The actuator has a U-shaped front shape that is perpendicular to the paper transport direction, and rotates about a shaft provided at one end of the actuator so that both the first and second postures are obtained. 2. A sheet abutting portion where a sheet passing through the first sheet conveying path abuts at a substantially central portion thereof, and the sheet guiding portion around the other end. The paper guide device described in 1.   The actuator always holds the second posture for guiding the paper passing through the second paper transport path by the biasing means, and when transporting the paper through the first paper transport path, When the conveyed paper comes into contact with the actuator, the posture is changed to the first posture that detects the presence of the paper passing through the first paper conveyance path against the urging force of the urging means. The sheet guiding apparatus according to claim 1 or 2.   A guide member on the first paper conveyance path side that is immediately downstream of the actuator in the paper conveyance direction of the actuator with respect to the first paper conveyance path and that forms the second paper conveyance path is provided with a rotation member. The paper guide device according to any one of claims 1 to 3.   The paper guide device according to claim 4, wherein the rotating member rotates according to the movement of the paper.   Between the first paper transport path and the second paper transport path, in the vicinity of the merging point, both an open posture for opening the first paper transport path and a closed posture for closing are provided. The sheet guide device according to any one of claims 1 to 5, further comprising a claw member that can be taken and always maintains a closed posture.   A movable guide is provided between the first paper conveyance path and the second paper conveyance path, and the claw member is provided in a portion of the guide rib provided on the movable guide on the side of the joining point. The paper guide device according to claim 6.   The paper guide device according to claim 6 or 7, wherein the claw member always maintains a closed posture by a weight of the claw member itself.   An image forming apparatus comprising the paper guide device according to claim 1.

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