JP2017193387A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus which can prevent attachment of a re-conveyance part from being forgotten with an inexpensive configuration in such a configuration that a sheet cassette and the re-conveyance part can be inserted/withdrawn into/from the same side face.SOLUTION: An image formation apparatus 1 comprises: a first chute 76 which constitutes a re-conveyance part; and a second chute 77 which can be inserted/withdrawn. The image formation apparatus also comprises: a sheet cassette guide part 91 which guides the sheet cassette 3 in a manner of being inserted/withdrawn; a chute guide part 92 which guides the second chute 77 in a manner of being inserted/withdrawn; and a lock member 93 which can move between a first position for preventing attachment by protruding in a region where the sheet cassette 3 passes and a second position for allowing attachment by moving to a position outside the region where the sheet cassette 3 passes when the sheet cassette 3 is inserted, is located at the first position when the second chute 77 is not attached, and is located at the second position when the second chute 77 is attached.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus including a sheet cassette and capable of duplex printing.

  2. Description of the Related Art Conventionally, in an image forming apparatus capable of duplex printing, a configuration in which a part of a re-conveying path is disposed below a paper feed cassette (sheet cassette) is known (see Patent Document 1). In Patent Document 1, the paper feed cassette is detachable from the front side of the image forming apparatus, and the re-conveying section that conveys the sheet along the re-conveying path is detachable from the back side of the image forming apparatus. This facilitates jam processing.

JP 2011-32023 A

  However, according to the configuration of Patent Document 1, a space for attaching and detaching the re-conveying unit is required on the back side of the image forming apparatus. In addition, when attaching and detaching the re-conveying unit, the user has to work around the back side of the image forming apparatus. Therefore, the jam processing becomes easy, but there is room for improvement in terms of usability.

  Therefore, a configuration in which the sheet cassette and the re-conveying unit can be inserted and removed from the front side of the image forming apparatus is conceivable. According to this configuration, the reconveyed sheet needs to pass through the front portion of the sheet cassette from the reconveying unit upward from the bottom, and the front side of the reconveying unit is usually covered with the sheet cassette. Therefore, in the jam processing, the sheet cassette is extracted and then the re-conveying unit is extracted, and in the re-installation, the re-conveying unit is mounted and then the sheet cassette is mounted.

  When such a configuration is employed, there is a possibility that a mistake of forgetting to mount the re-transporting unit and mounting the sheet cassette at the time of re-mounting may occur. As a countermeasure, it may be possible to provide a sensor for detecting forgetting to attach the re-conveying unit and to control the user to be warned. However, there is a problem that the cost increases.

  An object of the present invention is to provide an image forming apparatus that can prevent forgetting to attach a reconveying unit with an inexpensive configuration in a configuration in which the sheet cassette and the reconveying unit can be inserted and removed from the same side surface.

  The image forming apparatus of the present invention includes a casing and a sheet cassette that supports the sheet, and an image is formed on the casing by the image forming section that forms an image on the sheet and the image forming section. A discharge tray for supporting the sheet, a conveyance path for conveying the sheet from the sheet cassette to the discharge tray via the image forming unit, and between the image forming unit and the discharge tray in the conveyance path. A re-conveying path that branches from a branch portion of the sheet and joins a joining portion between the sheet cassette and the image forming portion, wherein a sheet on which an image is formed by the image forming portion is transferred from the branch portion to the joining portion. A re-carrying path for re-carrying, a first chute for guiding the sheet along the re-carrying path, and a second chute for guiding the sheet along the re-carrying path, A second chute that can be mounted at a chute mounting position that is sandwiched between one chute and the sheet cassette, and a sheet that is positioned between the transport path and the re-transport path from outside the housing. A sheet cassette guide part that guides the cassette to the mounting position so that it can be inserted and removed, a chute guide part that guides the second chute to the chute mounting position so that it can be inserted and removed, and the sheet cassette along the sheet cassette guide part. When the sheet cassette is inserted, the sheet cassette protrudes into a region through which the sheet cassette passes so that the sheet cassette cannot be mounted, and the sheet cassette can be mounted by moving to a position outside the region through which the sheet cassette passes. When the second chute is not attached to the housing. Is located in the first position, when the second chute is mounted to the housing is a structure in which the lock member, is provided positioned in the second position.

  According to the above configuration, the sheet cassette cannot be mounted unless the second chute is mounted.

  According to the present invention, in the configuration in which the sheet cassette and the second chute of the re-conveying unit can be inserted and removed from the same side surface, when the sheet cassette and the second chute are removed for jamming or the like, the second chute is attached. It is possible to prevent forgetting to install the sheet cassette. Further, by configuring this configuration with a lock member, it is possible to prevent forgetting to attach the second chute of the re-conveying unit with an inexpensive configuration.

1 is a central sectional view of an image forming apparatus 1 according to an embodiment. (A) is a front view which shows the sheet cassette guide part, chute guide part, and 1st chute of 1st Embodiment, (b) is AA sectional drawing of (a), (c) is (a). It is BB sectional drawing of. It is a figure which shows the state with which the 2nd chute | shoot of 1st Embodiment was mounted | worn in the chute mounting position, (a) is the figure which added the 2nd chute to Fig.2 (a), (b) is C of (a). -C sectional drawing, (c) is DD sectional drawing of (a). 3A and 3B are diagrams illustrating a state in which the sheet cassette according to the first embodiment is mounted at a sheet cassette mounting position, in which FIG. 3A is a diagram in which the sheet cassette is added to FIG. 3A, and FIG. E sectional drawing, (c) is FF sectional drawing of (a). (A) is a front view which shows the sheet cassette guide part, chute | shoot guide part, and 1st chute | shoot of 2nd Embodiment, (b) is GG sectional drawing of (a), (c) is (a). It is HH sectional drawing of. It is a figure which shows the state with which the 2nd chute | shoot of 2nd Embodiment was mounted to the near side of a press part, (a) is the figure which added the 2nd chute to Fig.5 (a), (b) is a figure of (a). JJ sectional drawing, (c) is KK sectional drawing of (a). It is a figure which shows the state with which the 2nd chute | shoot of 2nd Embodiment was mounted | worn in the chute mounting position, (a) is the figure which added the 2nd chute to Fig.5 (a), (b) is L of (a). -L sectional drawing, (c) is MM sectional drawing of (a). 8A and 8B are diagrams illustrating a state in which the sheet cassette according to the second embodiment is mounted at a sheet cassette mounting position, in which FIG. 7A is a diagram in which the sheet cassette is added to FIG. 7A, and FIG. N sectional drawing, (c) is QQ sectional drawing of (a). (A) is a front view which shows the sheet cassette guide part, chute | shoot guide part, and 1st chute | shoot of 3rd Embodiment, (b) is RR sectional drawing of (a), (c) is (a). It is TT sectional drawing of. It is a figure which shows the state with which the 2nd chute | shoot of 3rd Embodiment was mounted | worn in the chute mounting position, (a) is a figure which added the 2nd chute to Fig.9 (a), (b) is (a). FIG. 5C is a cross-sectional view taken along the line U-U of FIG. FIG. 10 is a diagram illustrating a state in which the sheet cassette according to the third embodiment is mounted at the sheet cassette mounting position, (a) is a diagram in which the sheet cassette is added to FIG. 10 (a), and (b) is a diagram of (a). WW sectional drawing, (c) is XX sectional drawing of (a).

[Entire configuration of image forming apparatus]
FIG. 1 is a central sectional view of an image forming apparatus 1 according to an embodiment. In the following description, the front-rear and top-bottom directions are determined based on the state where the image forming apparatus 1 is installed as shown in FIG. Further, when the front side is the front side, the right hand side is the right direction, and the left hand side is the left direction.

  The appearance of the image forming apparatus 1 is formed by a substantially rectangular housing 2. The housing 2 accommodates a sheet cassette 3, a feeder unit 4, a transport mechanism 5, an image forming unit 6, a re-transport mechanism 7, and a drive unit 8. In the housing 2, the image forming unit 6 is roughly arranged at the upper and central portions, the conveying mechanism 5 is below the image forming unit 6, the sheet cassette 3 is below the conveying mechanism 5, and the sheet is re-conveyed below the rear portion and the sheet cassette 3. The drive part 8 is arrange | positioned at the mechanism 7 and the lower part, respectively.

  A discharge tray 21 that supports a sheet on which an image is formed by the image forming unit 6 is provided on the upper surface of the housing 2. An opening 22 is provided in the lower part on the front side of the housing 2. The opening 22 serves as an insertion port between the sheet cassette 3 and the members constituting the re-conveying mechanism 7.

  The sheet cassette 3 is a box-like body having a sheet storage portion 31 whose upper side is opened, and supports a plurality of stacked sheets S. The bottom of the sheet storage unit 31 is a support surface 32 that supports the sheet S. In the present embodiment, the support surface 32 is a horizontal plane extending in the front-rear direction and the left-right direction. A pressing plate 33 is disposed on the front portion of the support surface 32. The front end side of the pressing plate 33 can swing up and down. When the sheet S is supplied to the image forming unit 6, the pressing plate 33 swings to push up the front end side of the sheet S stored in the sheet storage chamber 31 and press the sheet S against the upper supply roller 41.

  Further, the sheet cassette 3 has a front cover 34 that covers the opening 22. By covering the opening 22 with the front cover 34, sound leakage from the re-transport mechanism 7 can be suppressed, and the design can be improved. Further, by making the front cover 34 flush with the front surface of the housing 2, a sense of unity of appearance is increased.

  The sheet cassette 3 can be inserted into and removed from the housing 2 by moving in the front-rear direction along the sheet cassette guide 91 through the opening 22. FIG. 1 shows a state in which the sheet cassette 3 is mounted at a sheet cassette mounting position at a position sandwiched between the transport path P1 and the re-transport path P2.

  The sheet cassette guide 91 is provided at a position between the transport path P1 and the re-transport path P2 in the housing 2. The sheet cassette guiding portion 91 has a pair of grooves for positioning the sheet cassette 3 in the vertical and horizontal directions and guiding it in the front-rear direction. A space sandwiched between the grooves is an area through which the sheet cassette 3 passes. The sheet cassette guide unit 91 guides the sheet cassette 3 from the outside of the housing 2 so as to be inserted into and removed from the sheet cassette mounting position.

  The feeder unit 4 includes a supply roller 41, a transport roller 42, and a registration roller 43.

  The supply roller 41 is disposed above the front end side of the sheet cassette 3 and conveys the sheets S stacked on the sheet cassette 3 to the image forming unit 6. Below the front side of the supply roller 41, a separation pad (not shown) that separates the sheets S fed by the supply roller 41 one by one by applying a predetermined conveyance resistance to the sheet S is disposed.

  The conveyance roller 42 is disposed in a substantially U-shaped portion on the front side of the conveyance path P1 of the sheet S that is U-turned on the front side in the housing 2 and conveyed to the image forming unit 6. The conveyance roller 42 applies a conveyance force to the sheet S conveyed to the image forming unit 6 while being curved in a substantially U shape. Further, the transport roller 42 also has a role of giving a transport force to the sheet S transported from the re-transport path P2 and guiding it again to the transport path P1.

  The registration rollers 43 are arranged on the downstream side of the conveyance path P1 with respect to the conveyance rollers 42. The registration roller 43 contacts the front end of the sheet S conveyed by the conveyance roller 42 to correct the skew of the sheet S, and then conveys the sheet S toward the image forming unit 6.

  The transport mechanism 5 is wound around a driving roller 51 that rotates in conjunction with the image forming unit 6, a driven roller 52 that is rotatably disposed at a position separated from the driving roller 51, and the driving roller 51 and the driven roller 52. The transport belt 53 is provided. Then, the conveyance belt 53 rotates with the sheet S placed thereon, thereby conveying the sheet S along the conveyance path P <b> 1 and sending it below the developing toner cartridge 62 of the image forming unit 6.

  The image forming unit 6 uses an electrophotographic type in this embodiment. In addition, an image forming method such as a thermal method or an ink jet method may be used. The image forming unit 6 is a so-called direct tandem type capable of color printing, and includes a scanner unit 61, a developing toner cartridge 62, and a fixing unit 63.

  The developing toner cartridge 62 is an aggregate of four cartridges corresponding to toners of four colors of black, yellow, magenta, and cyan and arranged in series along the sheet S conveyance direction. The developing toner cartridge 62 includes photosensitive drums 621 to 624, a developing roller (not shown), a charger, and a toner container.

  The scanner unit 61 is provided in the upper part of the housing 2 and includes a laser light source, a polygon mirror, an fθ lens, and a reflecting mirror. The scanner unit 61 forms an electrostatic latent image on the surface of each photosensitive drum 621 to 624 in the developing toner cartridge 62.

  The fixing unit 63 is disposed on the downstream side in the transport direction of the photosensitive drums 621 to 624 in the transport path P1. The fixing unit 63 includes a heating roller 631 and a pressure roller 632. The heating roller 631 is disposed on the image forming surface side of the sheet S and is rotationally driven in synchronization with the conveyance belt 53 to apply a conveyance force to the sheet S while heating the toner. On the other hand, the heating roller 632 is disposed on the opposite side of the heating roller 631 across the sheet S, and presses the sheet S toward the heating roller 631. As a result, the pressure roller 632 receives the rotational force from the heating roller 631 via the sheet S in contact with the heating roller 631, and is driven to rotate.

  A discharge sensor 64 facing the transport path P1 is disposed behind the heating roller 631 and the pressure roller 632. When the sheet S is conveyed to the reconveying path P2, the trailing edge of the sheet S is detected by the discharge sensor 64, and the discharge rollers 751 and 752 are reversely rotated from the normal rotation at a predetermined timing from the detection.

  Such an image forming unit 6 forms an image on the sheet S as follows. That is, the surfaces of the photosensitive drums 621 to 624 are uniformly charged positively by a charger as the rotation occurs, and then exposed by high-speed scanning of a laser beam emitted from the scanner unit 61. Thereby, an electrostatic latent image corresponding to an image to be formed on the sheet S is formed on the surfaces of the photosensitive drums 621 to 624.

  Next, toner is supplied from the toner storage unit to the surfaces of the photosensitive drums 621 to 624 corresponding to the electrostatic latent images, and the toner carried on the surfaces of the photosensitive drums 621 to 624 is transferred to the sheet S. Then, the sheet S on which the toner has been transferred is conveyed to the fixing unit 63 and heated, and the toner is fixed on the sheet S to complete the image formation.

  The re-conveying mechanism 7 is for forming images on both sides of the sheet S. The sheet reversing unit 71 disposed at the rear of the housing 2 and the re-conveying disposed below the sheet cassette 3. Part 72. The sheet reversing unit 71 and the re-conveying unit 72 are branched from a branching part P11 between the image forming unit 6 and the discharge tray 21 in the conveying path P1, and a joining unit P12 between the sheet cassette 3 and the image forming unit 6 is used. It is arranged along the re-conveying path P2 that joins.

  The sheet reversing unit 71 includes discharge rollers 751 and 752 and re-conveying rollers 73 and 74. The discharge rollers 751 and 752 are a pair of opposed rollers, and are configured to be able to switch the rotation in the forward direction and the reverse direction. The discharge rollers 751 and 752 rotate in the forward direction when the sheet S is discharged onto the discharge tray 21 as described above, and rotate in the reverse direction when the sheet S is reversed and conveyed to the re-conveyance path P2. To do.

  The re-conveying rollers 73 and 74 are provided in the vertical direction along the re-conveying path P <b> 2 so that the sheet S can be conveyed from the discharge rollers 751 and 752 to the rear end side of the re-conveying unit 72.

  The re-conveying unit 72 includes a first chute 76 and a second chute 77 that guide the sheet S along the re-conveying path P2. The first chute 76 is disposed on the lower side of the re-transport path P2, and the second chute 77 is disposed on the upper side of the re-transport path P2 so as to face the first chute 76.

  The first chute 76 includes a rear conveyance roller 761 disposed on the rear side of the first chute 76 and a front conveyance roller 762 disposed on the front side as the first chute-side conveyance roller. The rear conveyance roller 761 and the front conveyance roller 762 are driven by the driving force from the driving unit 8.

  The second chute 77 includes a rear driven roller 771 disposed on the rear side of the second chute 77 and a front driven roller 772 disposed on the front side as the second chute-side transport roller. The rear driven roller 771 is in pressure contact with the rear transport roller 761, receives the rotational force from the rear transport roller 761, and is driven to rotate. The front driven roller 772 is in pressure contact with the front transport roller 762, receives the rotational force from the front transport roller 762, and is driven to rotate.

  The second chute 77 can be inserted into and removed from the housing 2 by moving in the front-rear direction along the chute guide portion 92 through the opening 22. FIG. 1 shows a state where the second chute 77 is mounted at a chute mounting position at a position sandwiched between the first chute 76 and the sheet cassette 3.

  The chute guide portion 92 is provided at a position between the first chute 76 and the sheet cassette 3 in the housing 2. The chute guide part 92 has a pair of grooves for positioning the second chute 77 in the vertical and horizontal directions and guiding it in the front-rear direction. The space sandwiched between the grooves is an area through which the second chute 77 passes. And the chute | shoot guide part 92 guides the 2nd chute | shoot 77 so that insertion / extraction is possible from the housing | casing 2 to the chute mounting position.

  The drive unit 8 is disposed below the first chute 76. The drive unit 8 may be configured to have an electric motor itself, or may be configured to distribute a part of the drive force transmitted to the transport mechanism 5 and the image forming unit 6 to the first chute 76. May be.

  Next, a configuration that allows the sheet cassette 3 and the second chute 77 to be inserted and removed will be described by taking three embodiments as examples.

[First Embodiment]
FIG. 2A is a front view showing the sheet cassette guide portion 91, the chute guide portion 92, and the first chute 76 of the first embodiment, and FIG. 2B is a cross-sectional view taken along the line AA in FIG. FIG. 2 and FIG. 2C are cross-sectional views taken along the line BB in FIG.

  FIG. 3 shows a state where the second chute 77 is mounted at the chute mounting position. 3A is a view in which a second chute 77 is added to FIG. 2A, FIG. 3B is a cross-sectional view taken along the line CC in FIG. 3A, and FIG. It is DD sectional drawing of a).

  FIG. 4 shows a state where the sheet cassette 3 is mounted at the sheet cassette mounting position. 4A is a view in which the sheet cassette 3 is added to FIG. 3A, FIG. 4B is a cross-sectional view taken along line EE of FIG. 4A, and FIG. 4C is FIG. It is FF sectional drawing of).

  On the left and right sides of the first chute 76, the frames 23 constituting the housing 2 are arranged extending upward. On the upper surface of the first chute 76, a pair of left and right lower rails 24 fixed to or integrally molded with the frame 23 are disposed. The lower rail 24 is a plate-like member that extends in the front-rear direction along the upper surface of the first chute 76, and a part of the re-transport path P <b> 2 is formed according to the thickness of the lower rail 24. A part of the upper surface of the lower rail 24 is a lower portion of the chute guide portion 92.

  On the upper surface of the lower rail 24, a pair of left and right wall portions 25 fixed to or integrally molded with the frame 23 are disposed extending upward. The wall portion 25 is disposed in parallel with the frame 23. The wall portion 25 is a left portion and a right portion of the sheet cassette guide portion 91 and the chute guide portion 92.

  An opening 251 extending in the vertical direction is formed at a position near the front of the wall 25. A space 252 is formed on the frame 23 side of the opening 251 as shown in FIG. A pair of left and right upper rails 253 extending in the front-rear direction in parallel with the lower rail 24 are formed in the middle portion of the wall portion 25 in the vertical direction. The lower surface of the upper rail 253 is an upper portion of the chute guide portion 92. Further, the upper surface of the upper rail 253 is a lower portion of the sheet cassette guide portion 91.

  One upper plate 26 is disposed over the upper surfaces of the left and right wall portions 25. The upper plate 26 is parallel to the upper rail 253, and the lower surface of the upper plate 26 is an upper portion of the sheet cassette guide portion 91.

  A lock member 93 is disposed in the space 252. The lock member 93 is a member that prevents the sheet cassette 3 from being mounted when the second chute 77 is not mounted. The lock member 93 of this embodiment includes a protruding member 931 and a biasing member 932. The protruding member 931 has a base 933, a first protrusion 934, and a second protrusion 935.

  The base 933 is a substantially rectangular parallelepiped member larger than the opening 251, and is disposed in the space 252 so as to face the opening 251.

  The first protrusion 934 is a rectangular parallelepiped protrusion formed on the surface of the base 933 on the opening 251 side. The first projecting portion 934 is formed in a position and size that can be inserted into a portion of the opening 251 that faces the sheet cassette guide portion 91. The protruding amount of the first protrusion 934 is a length that reaches the area through which the sheet cassette 3 passes when the base 933 is in contact with the wall 25. The front surface of the first protrusion 934 is a contact surface with the sheet cassette 3.

  Thus, the first protrusion 934 is orthogonal to the insertion direction of the sheet cassette 3 in the region through which the sheet cassette 3 passes when the sheet cassette 3 is inserted along the sheet cassette guide 91. The protrusions can protrude in a direction parallel to the support surface 32 in a state where the sheet cassette 3 is mounted at the sheet cassette mounting position. In other words, the first protrusion 934 protrudes into the region through which the sheet cassette 3 passes by moving horizontally in the left direction or the right direction.

  Further, the front surface, which is the contact surface of the first protrusion 934 with the sheet cassette 3, is perpendicular to the insertion direction of the sheet cassette 3. Therefore, when the sheet cassette 3 is inserted along the sheet cassette guide portion 91 in a state where the first protrusion 934 protrudes into the region through which the sheet cassette 3 passes, the rear end surface of the sheet cassette 3 is the first protrusion 934. Abutting on the front surface, the insertion of the sheet cassette 3 is stopped halfway.

  The second protrusion 935 is a triangular prism-shaped protrusion formed on the surface of the base 933 on the opening 251 side. The second projecting portion 935 is formed at a position and size that can be inserted into a portion of the opening 251 that faces the chute guide portion 92. The amount of protrusion of the second protrusion 935 is the same as that of the first protrusion 934. The front surface of the second protrusion 935 serves as a contact surface with the second chute 77.

  As described above, the second protrusion 935 can protrude in the same direction as the first protrusion 934 in the region through which the second chute 77 passes when the second chute 77 is inserted along the chute guide portion 92. It is a protrusion. That is, the 2nd projection part 935 protrudes in the field where the 2nd chute 77 passes by moving horizontally in the left direction or the right direction.

  In addition, the front surface, which is the contact surface of the second protrusion 935 with the second chute 77, is inclined so as to have an acute angle with respect to the insertion direction of the second chute 77. Therefore, when the second chute 77 is inserted along the chute guide portion 92 in a state where the second protrusion 935 protrudes into the region through which the second chute 77 passes, the left and right rear end portions of the second chute 77 are second. The second protrusion 935 is pushed into the space 252 side while incliningly contacting the front surface of the protrusion 935, and the second chute 77 is inserted to the chute mounting position.

  When the second projecting portion 935 is pushed in, the entire projecting member 931 is pushed in, so the first projecting portion 934 is also pushed in. As a result, the sheet cassette guide 91 is opened and the sheet cassette 3 can be mounted.

  The second projecting portion 935 may have a rectangular parallelepiped shape like the first projecting portion 934, and the left and right rear end portions of the second chute 77 may be cut obliquely to form an inclined surface. Even in this configuration, when the second chute 77 is inserted along the chute guide portion 92 in a state where the second protrusion 935 projects into the region through which the second chute 77 passes, the left and right rear end portions of the second chute 77 are inserted. The inclined surface of the second protrusion 935 obliquely contacts the tip of the second protrusion 935 to push the second protrusion 935 toward the space 252 and the second chute 77 is inserted to the chute mounting position.

  The urging member 932 is a direction in which the first protrusion 934 protrudes into an area through which the sheet cassette 3 passes, and a direction in which the second protrusion 935 protrudes into an area through which the second chute 77 passes. It is a member that biases the protruding member 931. That is, the urging member 932 is a member that urges the protruding member 931 in a direction in which the first protruding portion 934 and the second protruding portion 935 protrude from the opening 251.

  When the sheet cassette 3 and the second chute 77 are pulled out, the protruding member 931 protrudes by the biasing force of the biasing member 932. The biasing member 932 of this embodiment is a compression coil spring disposed between the base 933 and the frame 23. As the urging member 932, various elastic bodies such as springs and rubber can be used.

  According to the configuration of the first embodiment, by arranging the protruding member 931 on the side surface of the housing 2 so as to be movable in the horizontal direction, the installation space in the vertical direction of the lock member 93 can be reduced, and the image forming apparatus 1 is thin. Can be

[Second Embodiment]
FIG. 5A is a front view showing the sheet cassette guide portion 91, the chute guide portion 92, and the first chute 76 of the second embodiment, and FIG. 5B is a GG cross section of FIG. FIG. 5C is a cross-sectional view taken along the line HH in FIG.

  FIG. 6 shows a state where the second chute 77 is mounted up to the front of the pressing portion. 6A is a view in which a second chute 77 is added to FIG. 5A, FIG. 6B is a JJ cross-sectional view of FIG. 6A, and FIG. 6C is FIG. It is KK sectional drawing of a).

  FIG. 7 shows a state where the second chute 77 is mounted at the chute mounting position. FIG. 7A is a view in which a second chute 77 is added to FIG. 5A, FIG. 7B is an LL cross-sectional view of FIG. 7A, and FIG. It is MM sectional drawing of a).

  FIG. 8 shows a state where the sheet cassette 3 is mounted at the sheet cassette mounting position. 8A is a view in which the sheet cassette 3 is added to FIG. 7A, FIG. 8B is an NN cross-sectional view of FIG. 8A, and FIG. 8C is FIG. It is QQ sectional drawing of).

  First, similarly to the first embodiment, the frame 2, the lower rail 24, the wall portion 25, the upper rail 253, and the upper plate 26 are arranged in the housing 2. An opening 241 penetrating in the vertical direction is formed at a position near the front of the lower rail 24. An opening 254 penetrating in the vertical direction is formed at a position facing the opening 241 of the upper rail 253. A space portion 255 is formed between the wall portion 25 and the frame 23 and intersects with the left and right directions of the openings 241 and 254 as shown in FIG. The openings 241 and 254 communicate with the space 255. The lower end portion of the space portion 255 extends to the first chute 76.

  A lock member 94 is disposed in the space portion 255. The lock member 94 is a member that prevents the sheet cassette 3 from being mounted when the second chute 77 is not mounted. The lock member 94 of the present embodiment includes a protruding member 941 and an urging member 942. The protruding member 941 has a base portion 943, a third protruding portion 944, and a fourth protruding portion 945.

  The base portion 943 is a C-shaped member and is disposed in the space portion 254. The third protrusion 944 is a protrusion that is formed on the upper end of the base 943 and protrudes in the vertical direction. The third protrusion 944 is disposed in the opening 254, and the first end 944 a that is the upper end of the third protrusion 944 is an inclined surface and can protrude upward from the opening 254. On the other hand, the second end 944 b that is the lower end of the third protrusion 944 can protrude downward from the opening 254.

  The length of the third protrusion 944 is such that it protrudes above the opening 254 when the base 943 is lifted by the urging member 942 and below the opening 254 when the base 943 is pushed down. The length is projected to A front surface 944 c below the first end 944 a in the third protrusion 944 serves as a locking surface of the sheet cassette 3.

  As described above, the third protrusion 944 is orthogonal to the insertion direction of the sheet cassette 3 in the region through which the sheet cassette 3 passes when the sheet cassette 3 is inserted along the sheet cassette guide 91. The protrusions can project in a direction perpendicular to the support surface 32 in a state where the sheet cassette 3 is mounted at the sheet cassette mounting position. That is, the third protrusion 944 protrudes into an area through which the sheet cassette 3 passes by moving upward.

  Further, the front surface 944 c of the third protrusion 944 is perpendicular to the insertion direction of the sheet cassette 3. Therefore, when the sheet cassette 3 is inserted along the sheet cassette guide portion 91 in a state in which the front surface 944c of the third protrusion 944 protrudes into the region through which the sheet cassette 3 passes, the rear end surface of the sheet cassette 3 is the third protrusion. The sheet cassette 3 is stopped in the middle of contact with the front surface 944c of the portion 944.

The fourth protrusion 945 is a protrusion protruding upward and formed at the lower end of the base 943. The fourth protrusion 945 is disposed in the opening 241 and can protrude upward from the opening 241.
The amount of protrusion of the fourth protrusion 945 upward from the opening 241 is the same as the amount of protrusion of the third protrusion 944 upward from the opening 254. The front surface of the fourth protrusion 945 serves as a contact surface with the second chute 77.

  As described above, the fourth projecting portion 945 can project in the same direction as the third projecting portion 944 in the region through which the second chute 77 passes when the second chute 77 is inserted along the chute guide portion 92. It is a protrusion. That is, the fourth protrusion 945 moves upward and protrudes into the region through which the second chute 77 passes.

  In addition, the front surface, which is the contact surface of the fourth protrusion 945 with the second chute 77, is inclined so as to have an acute angle with respect to the insertion direction of the second chute 77. Therefore, when the second chute 77 is inserted along the chute guide portion 92 in a state in which the fourth projection 945 protrudes into the region through which the second chute 77 passes, the rear lower end portion of the second chute 77 becomes the fourth projection. The fourth projecting portion 945 is pushed into the space portion 255 side halfway by contacting the front surface of the portion 945 obliquely (see FIG. 6).

  When the fourth projecting portion 945 is pushed in, the entire projecting member 941 is pushed in, so that only the inclined surface of the first end portion 944a is pushed into the third projecting portion 944 until it protrudes from the opening 254. As a result, the sheet cassette guide 91 is opened and the sheet cassette 3 can be mounted.

  The fourth protrusion 945 may have a rectangular parallelepiped shape like the first protrusion 934, and the rear lower end portion of the second chute 77 may be cut obliquely to form an inclined surface. Even with this configuration, when the second chute 77 is inserted along the chute guide portion 92 in a state where the fourth protrusion 945 protrudes into the region through which the second chute 77 passes, The inclined surface comes into contact with the tip of the fourth protrusion 945 obliquely and pushes the fourth protrusion 945.

  Similarly, the third protrusion 944 may have a rectangular parallelepiped shape, and the rear lower end portion of the sheet cassette 3 may be cut out obliquely to form an inclined surface. However, in order to prevent the sheet cassette 3 from being mounted while the second chute is not mounted, this inclined surface has a height that does not contact the third protrusion 944 when the second chute 77 is not mounted.

  Further, the third projecting portion 944 and the fourth projecting portion 945 may be disposed close to the base portion 943 or may be integrated with the side surface of the base portion 943. Thereby, the protrusion member 941 can be reduced in thickness and the installation space of the lock member 93 in the left-right direction can be reduced.

  The urging member 942 is a direction in which the third protrusion 944 protrudes into an area through which the sheet cassette 3 passes, and a direction in which the fourth protrusion 945 protrudes into an area through which the second chute 77 passes. It is a member that biases the protruding member 941. That is, the urging member 942 is a member that urges the projecting member 941 in a direction in which the third projecting portion 944 and the fourth projecting portion 945 project from the openings 254 and 241.

  When the sheet cassette 3 and the second chute 77 are pulled out, the protruding member 941 protrudes by the urging force of the urging member 942. The biasing member 942 of this embodiment is a compression coil spring disposed between the base 933 and the lower portion of the first chute 76. As the urging member 942, an elastic body such as various springs or rubber can be used.

  Near the rear end of the chute guide portion 92, a pair of left and right pressing portions 95 that are protrusions provided on the lower surface of the upper rail 253 are provided. The front surface of the pressing portion is an inclined surface, and when the second chute 77 is inserted, the upper surface that is the surface of the second chute 77 on the sheet cassette 3 side is guided. And the press part 95 pushes down the 2nd chute 77 in the state in which the 2nd chute 77 was inserted, and hold | maintains it in an attachment position.

  As described above, when the pressing portion 95 presses the vicinity of the rear end portion of the second chute 77 downward, the rear driven roller 771 can be stably brought into pressure contact with the rear conveying roller 761.

  According to the configuration of the second embodiment, in the state where the sheet cassette 3 is not attached to the housing 2 and the second chute 77 is attached to the front of the pressing portion 95, the second chute 77 is applied by the urging force of the urging member 942. Is raised from the mounting position by the fourth protrusion 945. The first end 944a of the third protrusion 944 protrudes into the region through which the sheet cassette 3 passes, and the second end 944b of the third protrusion 944 is the surface of the second chute 77 on the sheet cassette 3 side. Abuts on top surface

  Therefore, in a state where the sheet cassette 3 is not mounted and the second chute 77 is mounted to the front of the pressing portion 95, the pressure contact between the rear driven roller 771 and the rear transport roller 761, the front driven roller 772 and the front transport roller 762 Both of the pressure contacts are opened. Therefore, when the second chute 77 is inserted / removed, the pressure contact between these rollers is released, so that the force for inserting / removing the second chute 77 can be reduced, and deterioration of these rollers due to friction can be suppressed.

  Further, according to the configuration of the second embodiment, the rear end portion of the second chute 77 in a state where the sheet cassette 3 is not attached to the housing 2 and is attached to the position where the second chute is pressed by the pressing portion 95. Is pushed down. As a result, the rear driven roller 771 comes into pressure contact with the rear conveying roller 761.

  Further, according to the configuration of the second embodiment, in a state where the sheet cassette 3 and the second chute 77 are attached to the housing 2, the first end 944 a of the third protrusion 944 is pushed by the bottom surface of the sheet cassette 3. Then, the upper surface of the second chute 77 is pushed by the second end 944b of the third protrusion 944. As a result, the front driven roller 772 comes into pressure contact with the front transport roller 762.

  As described above, in a state in which the sheet cassette 3 and the second chute 77 are mounted, the rear driven roller 771 is in pressure contact with the rear transport roller 761 and the front driven roller 772 is in pressure contact with the front transport roller 762 so that it can be used. .

[Third Embodiment]
FIG. 9A is a front view showing the sheet cassette guide portion 91, the chute guide portion 92, and the first chute 76 of the third embodiment, and FIG. 9B is an RR cross section of FIG. 9A. FIG. 9C is a cross-sectional view taken along line TT in FIG.

  FIG. 10 shows a state where the second chute 77 is mounted at the chute mounting position. 10A is a view in which a second chute 77 is added to FIG. 9A, FIG. 10B is a cross-sectional view taken along the line U-U in FIG. 10A, and FIG. It is VV sectional drawing of a).

  FIG. 11 shows a state where the sheet cassette 3 is mounted at the sheet cassette mounting position. FIG. 11A is a view in which the sheet cassette 3 is added to FIG. 10A, FIG. 11B is a WW sectional view of FIG. 11A, and FIG. 11C is FIG. It is XX sectional drawing of).

  First, similarly to the first embodiment, the frame 2, the lower rail 24, the wall portion 25, the upper rail 253, and the upper plate 26 are arranged in the housing 2. A notch portion 256 penetrating in the vertical direction is formed at a position near the front of the upper rail 253. A lock member 96 is disposed in the notch 256.

  The lock member 96 is a member that prevents the sheet cassette 3 from being mounted when the second chute 77 is not mounted. The lock member 96 of the present embodiment includes a rotating member 961, a limiting portion 962, and an urging member (not shown). The rotation member 961 includes a rotation shaft portion 963, a fifth protrusion 964, and a sixth protrusion 965.

  The rotation shaft portion 963 is a columnar member disposed in the notch portion 256. The rotation shaft portion 963 is supported by the wall portion 25 so as to be rotatable about a rotation shaft extending in the left-right direction.

  Thus, the rotation shaft portion 963 is disposed on the side surface between the sheet cassette guide portion 91 and the chute guide portion 92, is orthogonal to the insertion direction of the sheet cassette 3, and the sheet cassette 3 is at the sheet cassette mounting position. It is a member extending in a direction parallel to the support surface 32 in the mounted state. That is, the rotation shaft portion 963 is disposed on the side surface between the sheet cassette guide portion 91 and the chute guide portion 92 and extends in the horizontal direction perpendicular to the insertion / extraction direction of the sheet cassette 3 and the second chute 77.

  The fifth protrusion 964 is a rectangular parallelepiped protrusion extending upward from the rotation shaft 963. The protruding amount of the fifth protrusion 964 is set to a length that reaches the area through which the sheet cassette 3 passes in a state where the fifth protrusion 964 is in contact with the limiting portion 962. The front surface of the fifth protrusion 964 is a contact surface with the sheet cassette 3.

  As described above, the fifth protrusion 964 is orthogonal to the insertion direction of the sheet cassette 3 in the region through which the sheet cassette 3 passes when the sheet cassette 3 is inserted along the sheet cassette guide 91. The protrusions can project in a direction perpendicular to the support surface 32 in a state where the sheet cassette 3 is mounted at the sheet cassette mounting position. That is, the fifth protrusion 964 protrudes into the region through which the sheet cassette 3 passes by rotating in the front-rear direction.

  In addition, the rear surface of the fifth protrusion 964 is limited when the front surface, which is the contact surface of the fifth protrusion 964 with the sheet cassette 3, is perpendicular to the insertion direction of the sheet cassette 3. It abuts against the portion 962 and does not rotate backward any further. Therefore, when the sheet cassette 3 is inserted along the sheet cassette guide portion 91 in a state in which the fifth protrusion 964 protrudes into the region through which the sheet cassette 3 passes, the rear end surface of the sheet cassette 3 becomes the fifth protrusion 964. Abutting on the front surface, the insertion of the sheet cassette 3 is stopped halfway.

  The sixth projecting portion 965 is formed symmetrically with the fifth projecting portion 964 across the rotation shaft portion 963. That is, the sixth projecting portion 965 is a projecting portion that extends downward from the rotating shaft portion 963 and projects into the region through which the second chute 77 passes. The front surface of the sixth projecting portion 965 is a contact surface with the second chute 77.

  As described above, the sixth projecting portion 965 is a projecting portion that can project into a region through which the second chute 77 passes when the second chute 77 is inserted along the chute guide portion 92. That is, the sixth projecting portion 965 projects in the region through which the second chute 77 passes by rotating in the front-rear direction.

  Further, when the second chute 77 is inserted along the chute guide portion 92 in a state where the sixth projection 965 protrudes into the region through which the second chute 77 passes, the left and right rear end portions of the second chute 77 become the sixth. The sixth projecting portion 965 is brought into contact with the front surface of the projecting portion 965 and rotated backward to move into the notch portion 256. Thereby, the second chute 77 is inserted to the chute mounting position.

  As the sixth protrusion 965 rotates backward, the fifth protrusion 964 rotates forward, and the fifth protrusion 964 moves into the notch 256. As a result, the sheet cassette guide 91 is opened and the sheet cassette 3 can be mounted.

  The limiting portion 962 is a rectangular parallelepiped member that protrudes horizontally from the wall portion 25 into the notch portion 256 in the left-right direction. The restricting portion 962 is disposed at a position where the restricting portion 962 contacts the rear surface of the fifth projecting portion 256 when the fifth projecting portion 964 is positioned parallel to the vertical direction. As described above, the restricting portion 962 is a member that restricts the turning of the turning member 961 in the direction in which the fifth projecting portion 964 falls in the insertion direction of the sheet cassette 3.

  Note that the restricting portion 962 may be disposed at a position where the front surface of the fifth projecting portion 964 contacts the front surface of the sixth projecting portion 965 when the front surface of the fifth projecting portion 964 is perpendicular to the insertion direction of the sheet cassette 3.

  The urging member 966 is a member that urges the rotation member 961 in a direction in which the rear surface of the fifth protrusion 256 is in contact with the restriction portion 962. For example, the urging member 966 may be provided in the wall 25 or the rotation member 961. it can. As the urging member, various springs including torsion coil springs and elastic bodies such as rubber can be used. The biasing member 966 in the present embodiment is a torsion coil spring provided in the wall portion 25. When the sheet cassette 3 and the second chute 77 are pulled out, the urging force of the urging member 966 causes the rotation member 961 to rotate in a direction in which the fifth protrusion 964 and the sixth protrusion 965 are parallel to the vertical direction. .

[Effect of the embodiment]
It can be said that the first to third embodiments described above satisfy the following requirements. That is, the image forming apparatus 1 includes a housing 2 and a sheet cassette 3 that supports sheets. The housing 2 is provided with an image forming unit 6 that forms an image on a sheet and a discharge tray 21 that supports the sheet on which the image is formed by the image forming unit 6. The housing 2 is provided with a transport path P1 for transporting a sheet from the sheet cassette 3 to the discharge tray 21 via the image forming unit 6. In addition, the casing 2 is re-conveyed that branches from the branching part P11 between the image forming unit 6 and the discharge tray 21 in the transporting path P1 and joins the joining part P12 between the sheet cassette 3 and the image forming part 6. A re-conveying path P2 is provided for re-conveying the sheet on which the image is formed by the image forming unit 6 from the branching part P11 to the joining part P12. The housing 2 is provided with a first chute 76 that guides the sheet along the re-conveying path P2. The casing 2 is a second chute 77 that guides the sheet along the re-conveying path P <b> 2 and can be mounted at a chute mounting position that is sandwiched between the first chute 76 and the sheet cassette 3. A chute 77 is provided. Further, the casing 2 is provided with a sheet cassette guiding portion 91 that guides the sheet cassette 3 from the outside of the casing 2 to a sheet cassette mounting position at a position sandwiched between the transport path P1 and the re-transport path P2. It is done. The housing 2 is provided with a chute guide portion 92 that guides the second chute 77 to the chute mounting position so that it can be inserted and removed. The housing 2 has a first position where the sheet cassette 3 protrudes into a region through which the sheet cassette 3 passes when the sheet cassette 3 is inserted along the sheet cassette guide portion 91 and cannot be mounted. The second position where the sheet cassette 3 can be mounted by moving to a position outside the area through which the sheet passes, and when the second chute 77 is not mounted on the housing 2, When the second chute 77 is mounted on the housing 2 at the first position, a lock member positioned at the second position is provided.

  The lock member can also be expressed as follows. That is, the lock member protrudes into the chute guide portion 92 and the sheet cassette guide portion 91 when the second chute 77 and the sheet cassette 3 are not attached to the housing 2. When the sheet cassette 3 is inserted into the housing 2 with the second chute 77 not attached to the housing 2, the lock member comes into contact with the sheet cassette 3 to stop the mounting of the sheet cassette 3. When the second chute 77 is inserted into the housing 2, the lock member is pushed by the second chute 77 to open the chute guide portion 92 and the sheet cassette guide portion 91, and the second chute 77 and the sheet cassette 3 are moved. It can be attached to the housing 2.

  As described above, the sheet cassette 3 cannot be mounted unless the second chute 77 is mounted, so that the second chute 77 can be mounted when the sheet cassette 3 and the second chute 77 are removed for jam processing or the like. It is possible to prevent the sheet cassette 3 from being forgotten. Moreover, it can comprise at low cost by comprising this structure with a locking member, without using a sensor.

  Further, according to the first embodiment, the sheet cassette 3 has the support surface 32 that supports the sheet. The lock member 93 is orthogonal to the insertion direction of the sheet cassette 3 in an area through which the sheet cassette 3 passes when the sheet cassette 3 is inserted along the sheet cassette guide portion 91. Is inserted in the direction parallel to the support surface 32 in the state where the sheet cassette is mounted, and the second chute 77 passes when the second chute 77 is inserted along the chute guide portion 92. A projecting member 931 having a second projecting portion 935 that can project in the same direction as the first projecting portion 934 is provided in the region to be operated. Further, the lock member 93 is in a direction in which the first protrusion 934 protrudes into an area through which the sheet cassette 3 passes, and in a direction in which the second protrusion 935 protrudes into an area through which the second chute 77 passes. A biasing member 932 that biases the protruding member 931 is provided.

  According to this configuration, by arranging the protruding member 931 on the side surface of the housing 2 so as to be movable in the horizontal direction, the installation space in the vertical direction of the lock member 93 can be reduced, and the image forming apparatus 1 can be thinned. it can.

  Further, according to the first embodiment, the contact surface of the first protrusion 934 with the sheet cassette 3 is perpendicular to the insertion direction of the sheet cassette 3, and the second protrusion 935 is in contact with the second chute 77. The contact surface is inclined so as to have an acute angle with respect to the insertion direction of the second chute 77.

  According to this configuration, the lock member 93 can be formed with an inexpensive configuration.

  Further, according to the second embodiment, the sheet cassette 3 has the support surface 32 that supports the sheet. The lock member 94 is orthogonal to the insertion direction of the sheet cassette 3 in a region through which the sheet cassette 3 passes when the sheet cassette 3 is inserted along the sheet cassette guide portion 91, and the sheet cassette 3 is A third projection 944 that can project in a direction perpendicular to the support surface 32 in the cassette mounting position and a region through which the second chute 77 passes when the second chute 77 is inserted along the chute guide 92. A projecting member having a fourth projecting portion 945 that can project in the same direction as the third projecting portion 944 is provided. Further, the lock member 94 protrudes in a direction in which the third protruding portion protrudes into an area through which the sheet cassette 3 passes, and in a direction in which the fourth protruding portion protrudes into an area through which the second chute 77 passes. An urging member for urging 941 is provided.

  According to this configuration, the lock member 94 can also be formed by disposing the protruding member 941 on the side surface of the housing 2 so as to be movable in the vertical direction.

  Further, according to the second embodiment, the contact surface of the third protrusion 944 with the sheet cassette 3 is perpendicular to the insertion direction of the sheet cassette 3, and the second protrusion 945 is in contact with the second chute 77 of the fourth protrusion 945. The contact surface is inclined so as to have an acute angle with respect to the insertion direction of the second chute 77.

  According to this configuration, the lock member 94 can be formed with an inexpensive configuration.

  The image forming apparatus according to the second embodiment is provided with first chute-side conveyance rollers 761 and 762 for re-conveying the sheet provided on the first chute 76 and the second chute 77, Second chute-side transport rollers 771 and 772 that are in pressure contact with the transport rollers 761 and 762 are provided. Then, in a state where the sheet cassette 3 is not mounted on the housing 2 and the second chute 77 is mounted, the second chute 77 is lifted from the mounting position by the fourth protrusion 945 by the biasing force of the biasing member 942, The first end 944a of the third protrusion 944 protrudes into the region through which the sheet cassette 3 passes, and the second end 944b of the third protrusion 944 contacts the surface of the second chute 77 on the sheet cassette 3 side. Further, in a state where the sheet cassette 3 and the second chute 77 are mounted on the housing 2, the first end 944 a of the third protrusion 944 is pushed on the bottom surface of the sheet cassette 3, and the second of the third protrusion 944 is pressed. The surface of the second chute 77 on the sheet cassette 3 side is pushed by the end portion 944b, and the second chute-side transport rollers 771 and 772 come into pressure contact with the first chute-side transport rollers 761 and 762.

  According to this configuration, in a state where the sheet cassette 3 and the second chute 77 are mounted, the second chute-side transport rollers 771 and 772 are in pressure contact with the first chute-side transport rollers 761 and 762, while the sheet cassette 3 In a state where the second chute 77 is mounted without being mounted, the pressure contact between the second chute-side transport rollers 771 and 772 and the first chute-side transport rollers 761 and 762 is released. As a result, when the second chute 77 is inserted / removed when the sheet cassette 3 is not attached, the pressure contact of the rollers 761, 762, 771, 772 is released, so that the force for inserting / removing the second chute 77 is small. At the same time, the deterioration of the rollers 761, 762, 771, 772 can be suppressed.

  Further, according to the second embodiment, the lock member 94 is disposed in the vicinity of the insertion opening of the sheet cassette 3 and the second chute 77. In addition, a pressing portion 95 for pressing the surface of the second chute 77 on the sheet cassette 3 side is provided in the vicinity of the back end portion on the opposite side to the insertion port of the sheet cassette guide portion 91 and the chute guide portion 92.

  According to this configuration, by pressing both ends of the second chute 77 in the insertion direction, the second chute-side transport rollers 771 and 772 can be stably brought into pressure contact with the first chute-side transport rollers 761 and 762. .

  Further, according to the third embodiment, the sheet cassette 3 has the support surface 32 that supports the sheet. The lock member 96 is disposed on the side surface between the sheet cassette guide portion 91 and the chute guide portion 92, is orthogonal to the insertion direction of the sheet cassette 3, and is in a state in which the sheet cassette 3 is mounted at the sheet cassette mounting position. A rotation shaft portion 963 extending in a direction parallel to the support surface 32, a fifth protrusion 964 extending from the rotation shaft portion 963 and projecting into a region through which the sheet cassette 3 passes, and extending from the rotation shaft portion 963. A rotating member 961 having a sixth protrusion 965 protruding into the region through which the second chute 77 passes is provided. Further, the lock member 96 includes a restricting portion 962 that restricts the turning of the turning member 961 in a direction in which the fifth projecting portion 964 falls in the insertion direction of the sheet cassette 3. The lock member 96 includes an urging member that urges the rotating member 961 in a direction restricted by the restriction portion 962.

  According to this configuration, the lock member 96 can also be formed by disposing the rotation member 961 on the side surface of the housing 2 so as to be rotatable.

  Further, according to the image forming apparatuses of the first to third embodiments, the end surface of the sheet cassette 3 covers the insertion opening of the chute guide portion 92 in a state where the sheet cassette 3 is mounted on the housing 2.

  According to this configuration, sound leakage from the re-transport path P2 can be suppressed and design properties can be improved.

  Further, according to the image forming apparatuses of the first to third embodiments, the surface on the insertion port side of the sheet cassette 3 of the housing 2 is the front surface that is on the user side in use.

  According to this configuration, since the user can operate from the front side, it is easy to use.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Housing | casing 3 Sheet cassette 6 Image forming part 21 Discharge tray 32 Support surface 76 1st chute 77 2nd chute 91 Sheet cassette guide part 92 Chute guide part 93 Lock member 94 Lock member 96 Lock member 761 Rear conveyance roller (First chute side transport roller)
762 Front conveying roller (first chute side conveying roller)
771 Rear driven roller (second chute side transport roller)
772 Front driven roller (second chute-side transport roller)
931 Protruding member 932 Energizing member 934 First projecting portion 935 Second projecting portion 941 Protruding member 942 Energizing member 944 Third projecting portion 944a First end portion 944b Second end portion 945 Fourth projecting portion 961 Rotating member 962 Restriction 963 Rotating shaft 964 5th protrusion 965 6th protrusion P1 Conveyance path P2 Reconveyance path P11 Branching section P12 Merging section

Claims (10)

A housing,
A sheet cassette for supporting the sheet,
In the case,
An image forming unit that forms an image on the sheet;
A discharge tray that supports the sheet on which an image is formed by the image forming unit;
A transport path for transporting the sheet from the sheet cassette to the discharge tray via the image forming unit;
A re-transport path that branches from a branch section between the image forming section and the discharge tray in the transport path and joins a merging section between the sheet cassette and the image forming section, the image forming section A re-conveying path for re-conveying the sheet on which the image is formed from the branching unit to the joining unit;
A first chute for guiding the sheet along the re-conveying path;
A second chute for guiding the sheet along the re-conveying path, the second chute capable of being mounted at a chute mounting position at a position sandwiched between the first chute and the sheet cassette;
A sheet cassette guide portion that guides the sheet cassette from the outside of the housing to a sheet cassette mounting position at a position sandwiched between the conveyance path and the re-conveyance path;
A chute guide portion for guiding the second chute to the chute mounting position so as to be insertable / removable;
When the sheet cassette is inserted along the sheet cassette guide portion, a first position that protrudes into a region through which the sheet cassette passes and cannot be mounted, and outside the region through which the sheet cassette passes. A second position that allows the sheet cassette to be mounted by moving to a position, and is positioned at the first position when the second chute is not mounted on the housing. An image forming apparatus comprising: a lock member positioned at the second position when the second chute is attached to the housing. The sheet cassette has a support surface for supporting the sheet,
The locking member is
When the sheet cassette is inserted along the sheet cassette guide portion, it is orthogonal to the insertion direction of the sheet cassette in an area through which the sheet cassette passes, and the sheet cassette is at the sheet cassette mounting position. A first protrusion that can project in a direction parallel to the support surface in the mounted state, and a region through which the second chute passes when the second chute is inserted along the chute guide portion; A projecting member having a second projecting portion that can project in the same direction as the one projecting portion;
The first projecting portion biases the projecting member in a direction projecting into the region through which the sheet cassette passes and the second projecting portion projects into the region through which the second chute passes. The image forming apparatus according to claim 1, further comprising: an urging member that performs the operation. The contact surface of the first protrusion with the sheet cassette is perpendicular to the insertion direction of the sheet cassette,
The image forming apparatus according to claim 2, wherein a contact surface of the second projecting portion with the second chute is inclined so as to form an acute angle with respect to an insertion direction of the second chute. The sheet cassette has a support surface for supporting the sheet,
The locking member is
When the sheet cassette is inserted along the sheet cassette guide portion, the sheet cassette passes through the region through which the sheet cassette passes, and the sheet cassette is mounted at the sheet cassette mounting position. A third projection that can project in a direction perpendicular to the support surface in a state, and the third projection in a region through which the second chute passes when the second chute is inserted along the chute guide portion. A projecting member having a fourth projecting portion that can project in the same direction as the portion;
The third projecting portion biases the projecting member in a direction projecting into the region through which the sheet cassette passes and the fourth projecting portion projects into the region through which the second chute passes. The image forming apparatus according to claim 1, further comprising: an urging member that performs the operation. The contact surface of the third protrusion with the sheet cassette is perpendicular to the insertion direction of the sheet cassette,
5. The image forming apparatus according to claim 4, wherein a contact surface of the fourth protrusion with the second chute is inclined so as to form an acute angle with respect to an insertion direction of the second chute. A first chute-side conveyance roller for re-conveying the sheet provided on the first chute;
A second chute-side transport roller that is provided on the second chute and is in pressure contact with the first chute-side transport roller;
In a state where the sheet cassette is not mounted on the housing and the second chute is mounted, the second chute is lifted from the mounting position by the fourth protrusion by the biasing force of the biasing member, The first end of the three projections protrudes into the region through which the sheet cassette passes, the second end of the third projection contacts the surface of the second chute on the sheet cassette side,
In a state where the sheet cassette and the second chute are mounted on the housing, the first end of the third protrusion is pushed on the bottom surface of the sheet cassette, and the second end of the third protrusion is 6. The image formation according to claim 4, wherein a surface of the second chute on the sheet cassette side is pressed, and the second chute-side conveyance roller is in pressure contact with the first chute-side conveyance roller. apparatus. The lock member is disposed in the vicinity of the insertion opening of the sheet cassette and the second chute,
7. The pressing portion for pressing the sheet cassette side surface of the second chute is provided in the vicinity of the back end portion on the opposite side of the insertion opening of the sheet cassette guide portion and the chute guide portion. The image forming apparatus described. The sheet cassette has a support surface for supporting the sheet,
The locking member is
Arranged on the side surface between the sheet cassette guide portion and the chute guide portion, orthogonal to the insertion direction of the sheet cassette, and parallel to the support surface in a state where the sheet cassette is mounted at the sheet cassette mounting position. A rotation shaft portion extending in the direction, a fifth protrusion portion extending from the rotation shaft portion and projecting into the region through which the sheet cassette passes, and a region extending from the rotation shaft portion and through which the second chute passes. A rotating member having a sixth protrusion protruding inward;
A restricting portion that restricts the turning of the turning member in a direction in which the fifth protruding portion falls in the insertion direction of the sheet cassette;
The image forming apparatus according to claim 1, further comprising an urging member that urges the rotating member in a direction restricted by the restriction portion.   The image according to any one of claims 1 to 8, wherein an end surface of the sheet cassette covers an insertion port of the chute guide portion in a state in which the sheet cassette is mounted on the housing. Forming equipment.   10. The image forming apparatus according to claim 1, wherein a surface of the housing on the side of the insertion opening of the sheet cassette is a front surface on a user side in a use state.

Images