JP2007219465A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a double-sided printing function and equipped with a manual feeding tray which turns to be opened/closed, and capable of achieving reduction in the manufacture cost and the miniaturization of an apparatus main body by decreasing the number of components. <P>SOLUTION: A conveying guide plate is not provided at a part of a double-sided conveying path 24 for conveying paper switched back by a paper ejection roller pair 23 to an image forming part 12 again when double-sided printing is performed, and the manual feeding tray 2 in a closed state is used as the conveying guide plate at that part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer having a double-sided printing function, and more particularly to an image forming apparatus provided with a manual feed tray.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers and printers that can print an image on both sides of a sheet are known. An image forming apparatus having such a double-sided printing function has an image on one side. There is a configuration in which a printed sheet is reversed and printing is performed on one side which is sent again to the image forming unit through a duplex printing conveyance path. In the image forming apparatus having such a configuration, it is necessary to provide a double-sided printing conveyance path in addition to the paper conveyance path during single-sided printing, leading to an increase in the size of the apparatus main body.

  Further, one side of the image forming apparatus configured as described above is rotatably supported by one end portion of the image forming apparatus so that it can be opened and closed, and can be stored in the apparatus main body when not in use. When the tray is provided, it is necessary to provide a space for storing the manual feed tray and a paper transport path for transporting paper fed from the manual feed tray to the image forming unit. Inviting an increase in size.

Therefore, Patent Document 1 discloses a part of a switchback conveyance path for switching back a sheet during double-sided printing in an image forming apparatus having a double-sided printing function and having a manual feed tray that can be rotated and opened and closed. By using a closed manual feed tray as a conveyance guide plate, an image forming apparatus capable of omitting a dedicated conveyance guide plate and reducing manufacturing costs and downsizing the apparatus main body is provided. Proposed.
Japanese Patent Laid-Open No. 10-268585

  However, in the image forming apparatus described in Patent Document 1, the manual feed tray in a closed state is used as a conveyance guide plate to reduce the size of the main body of the apparatus. However, a switch for switching back the paper in the main body of the apparatus. Since the back conveyance path is provided, the apparatus main body has not been reduced in size.

  In the present invention, in view of the above circumstances, in an image forming apparatus having a double-sided printing function and having a manual feed tray that can be rotated and opened and closed, the number of parts is further reduced, the manufacturing cost is further reduced, and the apparatus main body is reduced in size. An object of the present invention is to provide an image forming apparatus capable of achieving the above.

  In order to achieve the above object, the present invention provides a sheet feeding unit for stacking sheets, a discharge unit provided above the sheet feeding unit, a sheet conveyance path connecting the discharge unit and the sheet feeding unit, An image forming unit, a fixing unit, and a switchback roller arranged in order from the upstream side of the paper transport direction along the paper transport path, and both sides for transporting the paper switched back by the switchback roller to the upstream side of the image forming unit An image forming apparatus having a double-sided printing function provided with a printing conveyance path is provided with a manual feed tray that can be rotated and opened on the side surface of the apparatus main body, and constitutes a part of the double-sided printing conveyance path As the conveyance guide plate, the closed manual feed tray is used.

  According to the present invention, in the image forming apparatus configured as described above, one or more transport pulleys are disposed on the sheet stacking surface side of the manual feed tray, and the transport pulley is configured so that when the manual feed tray is closed, It is characterized in that a pair of conveyance rollers is configured by being pressed against a conveyance roller arranged on the apparatus main body side.

  According to the present invention, in the image forming apparatus configured as described above, the transport roller is provided with a cover member that is rotatably supported on the same axis as the rotation shaft of the transport roller, and the manual feed tray is closed. The cover member is retracted from the duplex printing conveyance path, and the conveyance roller is covered with the cover member when the manual feed tray is opened.

  According to the present invention, in the image forming apparatus having the above-described configuration, the apparatus main body is provided with a motor that applies a driving force to the transport roller, and a gear train that connects the motor and the transport roller. A drive transmission gear that can be connected to or separated from any one of the gears is disposed on the paper stacking surface side of the manual feed tray. When the manual feed tray is opened, the drive transmission gear is separated from the gear train. And the transmission of the driving force to the conveying roller is cut off.

  According to the present invention, in the image forming apparatus configured as described above, when the drive transmission gear is connected to the gear train, the resultant force of the pressure received at the meshing portion with the adjacent gear is centered on the support shaft of the manual feed tray. , And is configured to act as a rotational moment for rotating the manual feed tray in the closing direction.

  According to the present invention, in the image forming apparatus having the above-described configuration, one or more transport rollers are disposed on the sheet stacking surface side of the manual feed tray, and when the manual feed tray is closed, The arranged conveying pulley is pressed against the conveying roller to form a conveying roller pair, and a drive supply gear for supplying driving force to the conveying roller is provided on the apparatus main body side, and the manual feed tray is provided from the apparatus main body. A drive input gear is arranged to receive the drive of the input and transmit to the transport roller. When the manual feed tray is opened, the drive input gear is separated from the drive supply gear, and the drive force is transmitted to the transport roller. It is characterized by being configured to be cut off.

  According to the present invention, in the image forming apparatus having the above-described configuration, the pressure that the drive input gear receives at the meshing portion with the drive supply gear is adjusted to close the manual feed tray with respect to the support tray of the manual feed tray. It is characterized by being configured to act as a rotating moment to rotate.

  According to the present invention, in the image forming apparatus having the above-described configuration, an open / close detection unit that detects an open / close state of the manual feed tray is provided, and duplex printing can be designated only when the open / close detection unit detects the close of the manual feed tray. It is characterized by that.

  According to the present invention, in the image forming apparatus having the above configuration, a conveyance roller is disposed along the double-sided printing conveyance path, and the conveyance roller is configured to be driven independently by a double-side conveyance unit motor. When the open / close detection means detects the opening of the manual feed tray, the power supply to the double-sided conveyance unit motor is cut off.

  According to the present invention, in the image forming apparatus configured as described above, the open / close detection unit is an interlock switch, and the interlock switch is electrically connected to the double-sided conveyance unit motor and a power source. Yes.

  According to the first configuration of the present invention, in an image forming apparatus having a double-sided printing function provided with a manual feed tray that can be rotated and opened, it is closed as a conveyance guide plate that is part of a double-sided printing conveyance path. By using the manual feed tray in a state in which it is in a state, a part of the conveyance guide plate dedicated to the duplex printing conveyance path can be omitted, and the number of parts can be reduced, thereby reducing the manufacturing cost and the size of the apparatus main body. be able to.

  According to the second configuration of the present invention, in the image forming apparatus having the first configuration, when the manual feed tray is closed on the paper stacking surface side of the manual feed tray, the transport roller disposed on the apparatus main body side. By disposing the transport pulley at a position that is in pressure contact with the transport roller pair, even if the transported paper size is small, it can be transported reliably.

  According to the third configuration of the present invention, in the image forming apparatus of the second configuration, when the manual feed tray is open, the transport roller is covered with the cover member, so that the user erroneously rotates the transport. It is possible to prevent the user from touching the roller to be injured or the like, and to prevent the user from inadvertently touching the transport roller with his / her hand and causing the oil on the surface of the transport roller to adhere to the surface of the transport roller and reduce the transport force. Further, even when the manual feed tray is used for a long time, dust or the like adheres to the surface of the transport roller, thereby preventing the transport force from being reduced.

  According to the fourth configuration of the present invention, in the image forming apparatus having the second or third configuration, the drive transmission gear that is a part of the gear train that transmits the drive to the transport roller is the paper in the manual feed tray. When the manual feed tray is opened, the drive transmission gear is separated from the gear train together with the manual feed tray, and the drive transmission to the transport roller is interrupted and the transport roller is not driven. It is possible to prevent injury by touching the rotating transport roller by mistake.

  According to the fifth configuration of the present invention, in the image forming apparatus having the fourth configuration, the drive transmission gear is disposed on the apparatus main body side and transmits the drive to the drive transmission gear and the drive transmission gear. Since the resultant force of the pressure received at the meshing portion with the gear to which the drive is transmitted acts as a rotational moment for rotating the manual feed tray in the direction of closing the manual feed tray, the drive transmission gear and the device main body side The manual feed tray is prevented from being opened or half-opened by the pressure caused by the meshing with the arranged gear.

  According to the sixth configuration of the present invention, in the image forming apparatus having the first configuration, the conveyance roller is disposed on the sheet stacking surface side of the manual feed tray, and the main body of the device when the manual feed tray is closed. When the manual feed tray is opened by arranging the drive supply gear on the apparatus body side and the drive input gear on the manual feed tray, the transport pulley arranged on the side is pressed against the transport roller to form a pair of transport rollers. The drive input gear is separated from the manual feed tray, the drive is not transmitted from the drive supply gear to the drive input gear, and the transport roller is not driven. Therefore, the user accidentally touches the rotating transport roller and may be injured. Is prevented. In addition, since the conveyance roller is provided on the surface of the sheet on which the image is not formed, it is possible to prevent a decrease in the conveyance force due to toner contamination on the surface of the conveyance roller.

  According to the seventh configuration of the present invention, in the image forming apparatus having the sixth configuration, the pressure received by the drive input gear at the meshing portion with the drive supply gear is the manual feed tray with respect to the support shaft of the manual feed tray. Therefore, the manual feed tray is prevented from being opened or half-opened by the pressure generated by the engagement between the drive input gear and the drive supply gear.

  According to the eighth configuration of the invention, in the image forming apparatus having any one of the first to seventh configurations, an open / close detection unit that detects an open / close state of the manual feed tray is provided, and the open / close detection unit is configured to perform the manual feed. Since double-sided printing can be specified only when the closing of the tray is detected, double-sided printing cannot be specified by the user when the manual feed tray is opened, and double-sided printing is performed with the manual feed tray open by mistake. This can be prevented beforehand.

  According to the ninth configuration of the invention, in the image forming apparatus having the eighth configuration, the transport roller disposed along the duplex printing transport path is configured to be driven only by the duplex transport motor. When the manual feed tray is open, the interlock switch is turned off, the power supply from the power supply to the duplex transport motor is cut off, and the transport roller is not driven. It is possible to prevent injury by touching the transport roller.

  According to the tenth configuration of the present invention, the open / close detecting means is an interlock switch, and the interlock switch is electrically connected to the motor for the double-sided conveyance unit and the power source, thereby detecting the open / closed state of the manual feed tray. At the same time, the power supply can be switched to the double-sided transport motor.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 and 2 are schematic configuration diagrams of the image forming apparatus according to the first embodiment of the present invention. FIG. 1 shows a state in which the manual feed tray is closed, and FIG. 2 shows that the manual feed tray is opened. Indicates the state.

  A rectangular recess 1a is provided on the right side surface of the apparatus main body 1 of the image forming apparatus, and a manual feed tray 2 is rotatably supported by the support shaft 2a. As shown in FIG. 1, the manual feed tray 2 can be stored in a recess 1 a provided in the apparatus main body 1 by being closed when not in use. When in use, the sheet is rotated in the direction of the arrow A and opened as shown in FIG. Near the upper portion of the support shaft 2 a of the apparatus main body 1, a paper feed roller 3 that feeds the paper P stacked on the manual feed tray 2 is disposed.

  Further, on the paper stacking surface side of the manual feed tray 2, conveying pulleys 4 and 5 are disposed. These conveying pulleys 4 and 5 are disposed at positions that constitute a pair of conveying rollers by being pressed against conveying rollers 27 and 28 (to be described later) by urging means (not shown) when the manual feed tray 2 is closed. . Further, an open / close detection means 6 for detecting the open / close state of the manual feed tray is disposed at the upper end of the recess 1a.

  As the open / close detection means 6, various conventionally known sensors such as a photo sensor such as a photo interrupter or a physical sensor such as an actuator switch can be used. It is preferable to use an interlock switch that switches between power supply to a predetermined part and stoppage thereof, because it is possible to switch whether double-sided printing is specified as described later simultaneously with detection of the open / closed state of the manual feed tray 2.

  A paper feed unit 7 such as a paper feed cassette for storing stacked paper P is provided at the lower part of the apparatus main body 1. At one end of the paper feeding unit 7, a separation feeding unit 8 for feeding the stacked paper P one by one from the uppermost paper is provided. A sheet transport path 9 for transporting sheets fed from the manual feed tray 2 and the sheet feeding unit 7 vertically upward is formed above the separation feeding unit 8. Along the sheet transport path 9, a sheet transport path 9 is formed. A pair of conveyance rollers 10, a pair of registration rollers 11, an image forming unit 12, and a fixing unit 13 are arranged in this order from the upstream in the sheet conveyance direction.

  The image forming unit 12 includes an intermediate transfer belt 14 that is rotatably disposed on the left side of the sheet conveyance path 9 and a transfer roller 15 that is disposed on the right side of the sheet conveyance path 9. The intermediate transfer belt 14 includes a driving roller. 16 and a driven roller 17, and when the driving roller 16 is driven to rotate, it is rotated counterclockwise. The driving roller 16 is in contact with the transfer roller 15 via the intermediate transfer belt 14. A sheet made of dielectric resin is used for the intermediate transfer belt 14, and a belt in which both ends thereof are overlapped and joined to form an endless shape, or a belt without a seam (seamless) is preferably used.

  Below the intermediate transfer belt 14, four photosensitive drums 18 </ b> C, 18 </ b> M, 18 </ b> Y, and 18 </ b> K are arranged in contact with the intermediate transfer belt 14 in order from the left side in FIG. These photosensitive drums 18C to 18K are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively subjected to charging, exposure, development, and transfer processes. And a black image are sequentially formed. The fixing unit 13 includes a fixing roller 19 having a built-in heat source such as a halogen lamp, and a pressure roller 20 that presses against the fixing roller 19 and forms a nip through which a sheet passes.

  A paper discharge path 22 is formed at the downstream end of the paper transport path 9 so that the paper after image fixing is transported in a substantially horizontal direction and discharged to the discharge unit 21 so as to be continuous therewith. A paper discharge roller pair 23 is disposed at the downstream end of the path 22. The pair of paper discharge rollers 23 also serves as a switchback roller when performing duplex printing, and the paper discharge roller pair 23 switches back to the upper end of the paper discharge path 22 so as to be continuous therewith. A double-sided printing transport path 24 is formed for transporting the used paper to the image forming unit 12 again. Further, a switching claw 25 for guiding the switched back sheet to the duplex printing conveyance path 24 is disposed at the upper end portion of the sheet discharge path 22.

  The double-sided printing conveyance path 24 extends to the right side surface of the apparatus main body 1 and further extends downward, and its downstream end is formed so as to merge with the sheet conveyance path 9 upstream of the registration roller pair 11. A conveyance roller pair 26 and conveyance rollers 27 and 28 are arranged in this order from the upstream in the sheet conveyance direction along the duplex printing conveyance path 24. Here, as shown in FIG. 1, a conveyance guide plate is not provided in a part of the duplex printing conveyance path 24, and the closed manual feed tray 2 is used as the conveyance guide plate of this portion. Yes.

  Regarding the image forming operation by the image forming apparatus configured as described above, first, the operation during single-sided printing will be described. When the start of image formation is input by the user, first, the photosensitive drums 18C to 18K are rotationally driven, and after charging, exposure, and development processes, cyan, magenta, and magenta are formed on the surfaces of the photosensitive drums 18C to 18K. Yellow and black toner images are formed. Then, after an electric field is applied to the intermediate transfer belt 14 at a predetermined transfer voltage, the toner images on the photosensitive drums 18 </ b> C to 18 </ b> K are transferred onto the intermediate transfer belt 14. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image.

  Further, when the intermediate transfer belt 14 starts to rotate with the rotation of the driving roller 16 by a driving motor (not shown), the sheet is fed from the manual feed tray 2 or the sheet feeding unit 7, and the sheet conveying path 9 is moved by the conveying roller pair 10. The conveyed sheet is conveyed from the registration roller pair 11 to the image forming unit 12 at a predetermined timing. When the sheet is conveyed to the image forming unit 12, the full color image on the intermediate transfer belt 14 is transferred to the sheet by the transfer roller 15.

  The sheet on which the toner image has been transferred is conveyed along the sheet conveyance path 9 to the fixing unit 13 and is heated and pressurized by the fixing roller 19 and the pressure roller 20 to fix the toner image on the surface of the sheet. A predetermined full-color image is formed. The paper on which the full-color image is formed is transported from the paper transport path 9 to the paper discharge path 22 and is discharged to the discharge unit 21 by the paper discharge roller pair 23.

  Next, the operation during duplex printing will be described. Here, as described above, since the manual feed tray 2 is used as a part of the conveyance guide plate of the double-sided printing conveyance path 24, double-sided printing cannot be performed unless the manual feed tray 2 is closed. Therefore, manual feeding using the manual feed tray 2 cannot be performed during duplex printing. Note that the open / closed state of the manual feed tray 2 is detected by the open / close detection means 6, and when the manual feed tray 2 is detected to be open, the user cannot designate double-sided printing. It is controlled.

  When the user inputs the start of double-sided image formation after the manual feed tray 2 is closed and double-sided printing is possible, first, an image is formed on the surface of the paper in the same way as during single-sided printing described above. The paper on which single-sided printing has been completed is discharged from the paper transport path 9 through the paper discharge path 22 to the discharge unit 21. In the case of double-sided printing, the paper is discharged when the trailing edge of the paper enters the paper discharge path 22. The rotation direction of the paper roller 23 is reversed, and the paper is pulled back into the apparatus main body 1. The pulled-back paper is transported to the duplex printing transport path 24 without returning to the paper transport path 9 by the action of the switching claw 25.

  The paper transported to the duplex printing transport path 24 is further transported by transport rollers 27 and 28 and transport pulleys 4 and 5 driven by the transport rollers 27 and 28 downstream of the transport roller pair 26. After returning to the upstream side of the registration roller pair 11 in the paper conveyance path 9 and forming an image on the remaining one side in the same manner as the one-side printing described above, the paper discharge path 21 passes through the paper conveyance path 9 and the paper discharge path 22. Is discharged.

  As described above, by using the manual feed tray 2 in a closed state for a part of the conveyance guide plates of the duplex printing conveyance path 24, a part of the conveyance guide plate dedicated to the duplex printing conveyance path 24 is omitted. Since the number of parts can be reduced, the manufacturing cost can be reduced and the apparatus body can be downsized. Further, by disposing a transport pulley on a manual feed tray used as a transport guide plate, the transport can be reliably transported even when the transported paper size is small.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 3 and 4 are partial sectional views showing the configuration of the image forming apparatus according to the second embodiment of the present invention. FIG. 3 shows a state in which the manual feed tray is closed, and FIG. 4 shows the manual feed tray. It shows the opened state. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 1 or FIG. 2, and description is abbreviate | omitted.

  In the present embodiment, the transport rollers 27 and 28 are provided with cover members 29 and 30 that are rotatably supported coaxially with the respective rotation shafts. The cover members 29 and 30 are respectively provided with spring engaging projections 31 and 32 that protrude outward in the width direction of the duplex printing conveyance path 24, and the apparatus main body 1 has springs below the conveyance rollers 27 and 28, respectively. Engaging portions 33 and 34 are provided, and tension springs 35 and 36 are stretched so as to connect the respective spring engaging projections 31 and 32 and the spring engaging portions 33 and 34. Further, the cover members 29 and 30 are respectively provided with contact protrusions 37 and 38 protruding outward in the width direction of the double-sided printing conveyance path 24. When the manual tray 2 is closed, Contact pieces 39 and 40 are provided at positions facing the contact protrusions 37 and 38.

  With the above configuration, as shown in FIG. 3, when the manual feed tray 2 is closed, the cover members 29 and 30 are provided by the contact pieces 39 and 40 provided on the manual feed tray 2. When the abutting projections 37 and 38 are pushed in, the cover members 29 and 30 are pushed into the apparatus main body 1 and do not interfere with the double-sided printing conveyance path 24, and the manual feed tray 2 can be moved as shown in FIG. When the cover members 29 and 30 are opened, the cover members 29 and 30 are rotated downward by the pulling force of the tension springs 35 and 36 to cover the transport rollers 27 and 28. As a means for rotating the cover members 29 and 30, a compression spring or a torsion spring can be used in addition to the tension spring, and the cover members 29 and 30 can be configured to rotate by their own weights. is there.

  According to this embodiment, when the manual feed tray 2 is open, the transport rollers 27 and 28 are covered with the cover members 29 and 30, so that the user accidentally touches the rotating transport rollers 27 and 28 and is injured. In addition, it is possible to prevent the user from inadvertently touching the transport rollers 27 and 28 with his / her hand and attaching sebum and dirt to the surfaces of the transport rollers 27 and 28 to reduce the transport force. Furthermore, even when the manual feed tray 2 is used for a long time, dust and the like adhere to the surfaces of the transport rollers 27 and 28 to prevent the transport force from being lowered. Furthermore, since the cover members 29 and 30 are automatically opened and closed in synchronization with the opening and closing of the manual feed tray 2, a safe and stable double-sided conveyance mechanism can be realized with a simple mechanism without bothering the user.

  Next, a third embodiment of the present invention will be described with reference to FIGS. 5 and 6 are partial sectional views showing the configuration of the image forming apparatus according to the third embodiment of the present invention. FIG. 5 shows a state in which the manual feed tray is closed, and FIG. 6 shows the manual feed tray. It shows the opened state. FIG. 7 is a schematic diagram showing a connection example of a double-sided conveyance unit motor, a motor control board, and an interlock switch to the power source of the apparatus main body. 5 and 6, the same reference numerals are given to portions common to FIG. 1 or FIG. 2, and description thereof is omitted.

  In the present embodiment, the conveyance roller pair 26 and the conveyance rollers 27 and 28 arranged along the duplex printing conveyance path 24 are drive motors that drive other rollers such as the drive roller 16 arranged in the apparatus main body 1. (Not shown) and a drive train thereof are independent of each other, and the apparatus main body 1 is separately provided with a transport roller pair 26 and a duplex transport motor 41 for driving the transport rollers 27 and 28. Note that the double-sided conveyance unit motor 41 is connected to the motor control board 42 and the power source 43 of the apparatus body 1, and the drive is controlled by the motor control board 42.

  As shown in FIGS. 5 and 6, drive gears 44, 45, and 46 are provided coaxially with the conveyance roller pair 26 and the conveyance rollers 27 and 28, respectively. The reduction two-stage gear 48 is connected to the double-sided conveyance unit motor 41 via a motor pinion 47, and an idle that transmits driving from the reduction two-stage gear 48 to the drive gear 44 is provided above the reduction two-stage gear 48. A gear 49 is arranged. Further, the idle gears 50, 51, 52, and 53 are engaged with each other in order from the top, and the idle gear 51 is connected to the drive gear 45, and the idle gear 53 is connected to the drive gear 46. They are arranged so as to mesh with each other, and are configured to transmit drive to the drive gears 45 and 46.

  Further, in the present embodiment, an interlock switch 54 is used as the opening / closing detection means 6, and the interlock switch 54 includes a double-sided conveyance unit motor 41, a motor control board 42, and the like as shown in FIG. The power source 43 of the apparatus main body 1 is connected. Further, the manual feed tray 2 is provided with a pressing projection 55 at a position facing the interlock switch 54 when the manual feed tray 2 is closed, and when the manual feed tray 2 is closed as shown in FIG. When the manual feed tray 2 is opened as shown in FIG. 6, the interlock switch 54 is opened and turned off.

  By configuring as described above, as shown in FIG. 5, when the manual feed tray 2 is closed, the double-sided conveyance unit motor 41 is connected to the power source 43, and thus the double-sided conveyance unit motor 41. However, when the manual feed tray 2 is opened as shown in FIG. 6, the interlock switch 54 is turned OFF, and as shown in FIG. Since the power supply to the power supply is cut off and the transport rollers 27 and 28 are not driven, the user is prevented from accidentally touching the rotating transport rollers 27 and 28 and being injured.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9 are partial cross-sectional views showing the configuration of the image forming apparatus according to the fourth embodiment of the present invention. FIG. 8 shows a state in which the manual feed tray is closed, and FIG. 9 shows the manual feed tray. It shows the opened state. FIG. 10 is a diagram showing the positional relationship between the drive transmission gear arranged in the apparatus main body and the idle gear arranged in the manual feed tray. In FIGS. 8 and 9, the same reference numerals are given to portions common to FIGS. 1 to 6, and description thereof is omitted.

  In the present embodiment, as in the third embodiment, the drive of the double-sided conveyance unit motor 41 is transmitted to the conveyance rollers 27 and 28 via various gears. In the embodiment, the idle gear 50 meshed with the reduction two-stage gear 48 and the idle gear 51 is not arranged, and an idle gear 56 meshed with the reduction two-stage gear 48 is provided below the reduction two-stage gear 48. A drive transmission gear 57 is arranged in the manual feed tray 2 at a position where the manual feed tray 2 meshes with the idle gear 56 and the drive gear 45 when the manual feed tray 2 is closed.

  With the above configuration, as shown in FIG. 8, when the manual feed tray 2 is closed, the double-sided conveyance unit motor 41 is driven via the idle gear 56 and the drive transmission gear 57. Since it is transmitted to the gear 45 and further transmitted from the drive gear 45 to the drive gear 46 via the idle gears 51, 52 and 53, the transport rollers 27 and 28 are driven, as shown in FIG. When the manual feed tray 2 is opened, the drive transmission gear 57 is separated from the drive train together with the manual feed tray 2 so that the drive is not transmitted from the idle gear 56 to the drive gear 45, and the idle gears 51, 52, 53 and the drive gear 46 are not driven, and the transport rollers 27 and 28 are not driven. Therefore, the user accidentally touches the rotating transport rollers 27 and 28 to be injured. It is prevented.

  Here, the drive transmission gear 57 receives pressure in the pressure angle direction as shown by the arrow B in FIG. 10 at the meshing portion with the idle gear 56, and further at the meshing portion with the drive gear 45. 10, the pressure is received in the pressure angle direction indicated by the arrow C. The resultant force of the pressure in the arrow B direction and the pressure in the arrow C direction is the manual feed tray 2 with the support shaft 2a as a fulcrum. Is configured to act as a rotational moment that rotates in the closing direction (counterclockwise in FIG. 10). This prevents the manual feed tray 2 from being opened or half-opened due to the pressure generated by the engagement between the drive transmission gear 57 and the drive gear 45 or the idle gear 56.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS. 11 and 12 are partial cross-sectional views showing the configuration of the image forming apparatus according to the fifth embodiment of the present invention. FIG. 11 shows a state in which the manual feed tray is closed, and FIG. 12 shows the manual feed tray. It shows the opened state. FIG. 13 is a view showing the positional relationship between the idle gear arranged in the apparatus main body and the drive gear arranged in the manual feed tray. 11 and 12, the same reference numerals are given to portions common to FIGS. 1 to 6, and description thereof is omitted.

  In the present embodiment, conveying rollers 58 and 59 are disposed on the sheet stacking surface side of the manual feed tray 2. These transport rollers 58 and 59 are provided with belt pulleys 60 and 61 coaxially, respectively, and the transport rollers 58 and 59 are connected to each other by stretching a belt 62 around the belt pulleys 60 and 61. Yes. Further, a drive input gear 63 is provided on the same axis as the conveying roller 58.

  On the apparatus main body 1 side, conveying pulleys 67 and 68 are arranged at positions where they are pressed against the conveying rollers 58 and 59 by the urging means (not shown) when the manual feed tray 2 is closed to form a conveying roller pair. It is arranged. Further, on the apparatus main body 1 side, a drive supply gear 64 is disposed at a position where it engages with the drive input gear 63 when the manual feed tray 2 is closed, and this drive supply gear 64 is decelerated via allied gears 65 and 66. A two-stage gear 48 is connected.

  With the above configuration, when the manual feed tray 2 is closed as shown in FIG. 11, the drive of the double-sided conveyance unit motor 41 is driven through the allied gears 65 and 66 and the drive supply gear 64. Since the transfer rollers 58 and 59 are driven to be transmitted to the input gear 63, as shown in FIG. 12, when the manual feed tray 2 is opened, the drive input gear 63 is separated from the drive train together with the manual feed tray 2. Since the drive is not transmitted from the drive supply gear 64 to the drive input gear 63 and the conveying rollers 58 and 59 are not driven, the user accidentally touches the rotating conveying rollers 58 and 59 to cause injury. Is prevented. Further, since the conveyance rollers 58 and 59 are provided on the surface of the paper P where no image is formed, it is possible to prevent a decrease in conveyance force due to toner contamination on the surfaces of the conveyance rollers 58 and 59.

  Here, the drive input gear 63 receives pressure in the pressure angle direction indicated by the arrow D in FIG. 13 at the meshing portion with the drive supply gear 64. The pressure in the arrow D direction is supported by the support shaft. It is configured to act as a rotational moment for rotating the manual feed tray 2 in the closing direction (counterclockwise in FIG. 13) using 2a as a fulcrum. This prevents the manual feed tray 2 from being opened or half-opened due to the pressure generated by the engagement between the drive input gear 63 and the drive supply gear 64.

  In the third or fourth embodiment, similarly to the second embodiment, the cover is rotatably supported coaxially with the transport rollers 27 and 28 or the transport pulleys 67 and 68 disposed on the apparatus body 1 side. Members 29 and 30 can also be provided. Also in the fourth or fifth embodiment, when the manual feed tray 2 is opened using the interlock switch 54 for the open / close detection means 6 as in the third embodiment, the interlock switch 54 is It is also possible to configure so that the power supply to the double-sided transport motor 41 is cut off when it is opened and turned off. Furthermore, in the fourth or fifth embodiment, the conveyance roller pair 26 and the conveyance rollers 27 and 28 arranged along the double-sided printing conveyance path 24 include the drive roller 15 and the like arranged in the apparatus main body 1. The present invention can be applied even when the drive motor (not shown) for driving other rollers and the drive train thereof are not independent.

  In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although the above embodiment has been described using a 4-drum tandem color image forming apparatus, this can also be applied to other types of color image forming apparatuses and monochrome image forming apparatuses. Further, the position and number of the transport pulleys or transport rollers disposed on the manual feed tray can be appropriately changed according to the transport rollers or transport pulleys disposed on the duplex printing transport path.

  The present invention relates to an image forming apparatus such as a copying machine or a printer having a double-sided printing function, and can be used particularly for an image forming apparatus provided with a manual feed tray.

These are the schematic block diagrams of the image forming apparatus which concerns on 1st Embodiment of this invention, and are the schematic block diagrams which show the state by which the manual feed tray was closed. These are the schematic block diagrams of the image forming apparatus which concerns on 1st Embodiment of this invention, and are the schematic block diagrams which show the state by which the manual feed tray was opened. These are the fragmentary sectional views showing the composition of the image forming device concerning a 2nd embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was closed. These are the fragmentary sectional views showing the composition of the image forming device concerning a 2nd embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was opened. These are the fragmentary sectional views showing the composition of the image forming device concerning a 3rd embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was closed. These are the fragmentary sectional views showing the composition of the image forming device concerning a 3rd embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was opened. These are the schematic diagrams which show the example of a connection of the motor for double-sided conveyance parts, a motor control board | substrate, and an interlock switch with respect to the power supply of an apparatus main body in the image forming apparatus which concerns on 3rd Embodiment of this invention. These are the fragmentary sectional views showing the composition of the image forming device concerning a 4th embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was closed. These are the fragmentary sectional views showing the composition of the image forming device concerning a 4th embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was opened. These are the figures which show the positional relationship of the drive transmission gear arrange | positioned at an apparatus main body, and the idle gear arrange | positioned at a manual feed tray in the image forming apparatus which concerns on 4th Embodiment of this invention. These are the fragmentary sectional views showing the composition of the image forming device concerning a 5th embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was closed. These are the fragmentary sectional views showing the composition of the image forming device concerning a 5th embodiment of the present invention, and are the fragmentary sectional views showing the state where the manual feed tray was opened. These are the figures which show the positional relationship of the idle gear arrange | positioned at an apparatus main body and the drive gear arrange | positioned at a manual feed tray in the image forming apparatus which concerns on 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 1a Concave part 2 Manual feed tray 2a Spindle 3 Paper feed roller (manual paper feed)
4,5 Conveying pulley 6 Opening / closing detection means 7 Paper feeding section 8 Separating and feeding means 9 Paper transport path 11 Registration roller pair 12 Image forming section 13 Fixing section 18C, 18M, 18Y, 18K Photosensitive drum 21 Discharging section 22 Discharging path 23 discharge roller pair 24 double-sided printing conveyance path 25 switching claw 27, 28 conveyance roller 29, 30 cover member 41 double-sided conveyance motor 42 motor control base 43 power supply 44, 45, 46 drive gear 47 motor pinion 48 step gear 50, 51, 52, 53, 56 Idle gear 54 Interlock switch 57 Drive transmission gear 58, 59 Conveyance roller 60, 61 Belt pulley 62 Belt 63 Drive input gear 64 Drive supply gear 65, 66 Allied gear 67, 68 Conveyor pulley P Paper

Claims (10)

A sheet feeding unit for stacking sheets, a discharge unit provided above the sheet feeding unit, a sheet conveyance path connecting the discharge unit and the sheet supply unit, and upstream in the sheet conveyance direction along the sheet conveyance path A double-sided printing function comprising: an image forming unit, a fixing unit, and a switchback roller, which are arranged in order, and a double-sided printing conveyance path for conveying the paper switched back by the switchback roller to the upstream side of the image forming unit In an image forming apparatus having
A manual feed tray that can be rotated and opened is provided on a side surface of the apparatus main body, and the closed manual feed tray is used as a conveyance guide plate constituting a part of the duplex printing conveyance path. An image forming apparatus.   One or more transport pulleys are disposed on the sheet stacking surface side of the manual feed tray, and the transport pulley is pressed against a transport roller disposed on the apparatus main body side when the manual feed tray is closed. The image forming apparatus according to claim 1, further comprising a pair of conveying rollers.   The transport roller is provided with a cover member that is rotatably supported on the same axis as the rotation axis of the transport roller. When the manual feed tray is closed, the cover member is connected to the duplex printing transport path. The image forming apparatus according to claim 2, wherein the conveyance roller is covered with the cover member when the manual feed tray is opened.   The apparatus main body is provided with a motor for applying a driving force to the transport roller, and a gear train for connecting the motor and the transport roller, and can be connected or separated between any gears constituting the gear train. A drive transmission gear is disposed on the paper stacking surface side of the manual feed tray, and when the manual feed tray is opened, the drive transmission gear is separated from the gear train and the transmission of the drive force to the transport roller is cut off. The image forming apparatus according to claim 2, wherein the image forming apparatus is configured to be configured as described above.   When the drive transmission gear is connected to the gear train, the resultant torque of the pressure received at the meshing portion with the adjacent gear rotates around the support shaft of the manual feed tray in the direction of closing the manual feed tray. The image forming apparatus according to claim 4, wherein the image forming apparatus is configured to act as the above.   One or more transport rollers are disposed on the paper stacking surface side of the manual feed tray, and when the manual feed tray is closed, a transport pulley disposed on the apparatus main body side is pressed against the transport roller. A drive supply gear that constitutes a pair of conveyance rollers, and that supplies driving force to the conveyance rollers on the apparatus main body side, and that drives from the apparatus main body is input to the manual feed tray and is transmitted to the conveyance rollers. An input gear is arranged, and when the manual feed tray is opened, the drive input gear is separated from the drive supply gear, and the transmission of the driving force to the transport roller is cut off. The image forming apparatus according to claim 1.   The pressure received by the drive input gear at the meshing portion with the drive supply gear is configured to act as a rotational moment for rotating the manual feed tray in the closing direction with respect to the support tray of the manual feed tray. The image forming apparatus according to claim 6.   8. An open / close detecting means for detecting an open / closed state of the manual feed tray is provided, and duplex printing can be designated only when the open / close detecting means detects the closing of the manual feed tray. The image forming apparatus according to any one of the above.   A conveyance roller is disposed along the double-sided printing conveyance path, and the conveyance roller is configured to be driven independently by a double-side conveyance unit motor, and when the open / close detection unit detects the opening of the manual feed tray The image forming apparatus according to claim 8, wherein power supply to the double-sided conveyance unit motor is cut off.   The image forming apparatus according to claim 9, wherein the open / close detection unit is an interlock switch, and the interlock switch is electrically connected to the double-sided conveyance unit motor and a power source.

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