JP2014080038A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus having a compact and highly rigid frame structure while having two conveyance paths where double-sided image formation can be performed.SOLUTION: An inner frame 29 is fixed above a plane part 24a of a main frame 24 so as to connect a pair of side plates rising from the right and left sides. A triangular space, in a side view of an image forming apparatus, is formed to be surrounded by a plane of a first conveyance path 31 above the inner frame 29, a plane of a reversal conveyance path 34 below the inner frame 29, and an inside guide block 71 on a side near a U turn path. A plurality of composing members are arranged in each of the conveyance paths. Consequently, arrangement relationship of both conveyance paths can be held reliably while ensuring rigidity of a frame structure.

Description

  The present invention relates to an image forming apparatus capable of forming a double-sided image on a transported medium.

  2. Description of the Related Art Conventionally, various image forming apparatuses such as multifunction peripherals capable of forming double-sided images on a transported medium and having a scan / copy function and the like are known.

  In the configurations described in Patent Documents 1, 2, and 3, which are known as compact image forming apparatuses capable of forming double-sided images, U-turn conveyance is performed between the recording head (recording unit) and the sheet feeding cassette below the recording head (recording unit). A path and a platen for supporting the paper conveyed thereby are arranged, and a switchback roller pair (or a reversible discharge roller pair) is provided downstream of the recording head. After image formation (hereinafter also referred to as printing) on the upper surface of the paper fed from the paper cassette, the upstream end in the paper transport direction is sent to the position of the switchback roller pair, where the switchback roller pair is reversed. Thus, a configuration is disclosed in which a medium to be transported is sent in an inverted state between the recording unit and the platen via the U-turn transport path again from the reverse transport path provided below the platen, thereby forming a double-sided image.

  Further, in the image forming apparatus disclosed in Patent Document 3, in addition to a transported medium such as a recording sheet, other transported medium such as a medium tray on which a CD or a DVD is placed can be transported. Release means is provided for expanding (releasing the expansion) a gap in the conveyance path (a gap through which the medium to be conveyed can pass).

  Further, in the frame structure of the image forming apparatus disclosed in Patent Document 4, a metal and highly rigid stay member is screwed between the metal left and right side plates, and then the image forming apparatus is mounted on the left and right side plates. A plurality of constituent members are sequentially attached.

JP 2006-327793 A JP 2006-35802 A JP 2010-76421 A JP 2008-28988 A

  However, none of the above patent documents describes or suggests a compact and highly rigid frame structure while having two conveyance paths capable of duplex image formation (also called duplex printing). It was.

  An object of the present invention is to provide an image forming apparatus having a compact and highly rigid frame structure while having two conveyance paths capable of double-sided image formation (also referred to as double-sided printing).

An image forming apparatus according to the present invention includes a paper feeding unit that feeds a transported medium one by one from a lower paper feed cassette in the apparatus body to a recording unit, a recording unit that forms an image on the transported medium, and the recording unit. An image forming apparatus comprising: a first conveyance path for a medium to be conveyed that passes through a first conveyance path; and a second conveyance path for forming a double-sided image on the medium to be conveyed after having passed through the recording unit. The path is surrounded by a main frame that includes a flat portion that supports the paper feeding means and a pair of side plates that rise from both the left and right sides of the flat portion, and the pair of side plates includes an inner frame that extends above the flat portion. Is fixed, the first transport path is disposed above the inner frame, the second transport path is disposed below, and the first transport path and the second transport path are planes thereof, respectively. Are crossed on the downstream side in the transport direction of the transported medium. The first conveyance path and the second conveyance path are arranged up and down on the side close to the U-turn path for conveying the medium to be conveyed from the paper feed cassette to the recording unit. A connecting inner guide block is provided.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the image forming apparatus is substantially surrounded by the respective planes of the first conveyance path and the second conveyance path and the inner guide block of the U-turn path. A plurality of constituent members of the first transport path and a plurality of constituent members of the second transport path are disposed in a triangular space, and the inner frame is disposed in the triangular space.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the inner frame has a first surface close to a U-turn path for conveying a medium to be conveyed from the paper feed cassette to the recording unit. And a second surface located near the recording head of the recording unit and above the first surface, and the first surface and the second surface are connected to each other, and the first surface of the inner frame is One surface holds a conveyance pressing roller holder in a component of the first conveyance path and an inner guide block of the U-turn path, and at least a return conveyance driven roller in the second conveyance path on the second surface. The component member to be included is held.

  According to the present invention, in order to form a one-sided image on the transported medium fed from the paper feed cassette by the recording unit, after passing through the first transport path of the transported medium passing through the recording unit and the recording unit. Both of the conveyance paths to the second conveyance path for forming a double-sided image on the medium to be conveyed are provided on a main frame having a plane portion supporting the sheet feeding means and a pair of side plates rising from the left and right sides of the plane portion. Since the inner frame is fixed to the pair of side plates in the vertical space between the flat portion and the first transport path, the frame having two transport paths in the vertical direction is compact. And the rigidity of the entire frame structure can be increased.

  The first transport path is disposed above the inner frame, the second transport path is disposed below, and the first transport path and the second transport path have their respective planes The first conveyance path is formed on the side close to the U-turn path that conveys the medium to be conveyed from the paper feed cassette to the recording unit. Since the inner guide block that connects the second transport path and the second transport path is provided, the positional relationship between the two transport paths can be reliably maintained while ensuring the rigidity of the frame structure.

  According to the second aspect of the present invention, a plurality of constituent members of the first transport path are formed in a substantially triangular space surrounded by the respective planes of the second transport path and the inner guide block of the U-turn path. And a plurality of constituent members in the second transport path are disposed, and the inner frame is disposed in the triangular space, so that both transport paths are secured while ensuring the rigidity of the frame structure. It is possible to reliably maintain the arrangement relationship.

According to a third aspect of the present invention, the inner frame has a first surface close to a U-turn path for transporting a medium to be transported from the paper feed cassette to the recording unit, close to the recording head of the recording unit and the first frame. Since the second surface located above the first surface is provided, it is easy to arrange the second conveyance path in a downwardly inclined manner toward the U-turn path. And since the said 1st surface and the said 2nd surface are connected, the rigidity of an inner frame can be improved further.

  In addition, the first surface of the inner frame holds the conveyance pressing roller holder in the component of the first conveyance path and the inner guide block of the U-turn path, and the second surface conveys the second conveyance. Since the structural member including at least the return path driven roller in the path is held, the arrangement accuracy of the plurality of structural members is increased.

1 is a perspective view of a multifunction machine. It is a typical sectional view of a printer part. It is a perspective view of a printer part. It is a top view of the conveying apparatus which abbreviate | omits a carriage. FIG. 5A is a cross-sectional view taken along line VA-VA in FIG. 4, and FIG. 5B is a cross-sectional view at another location in FIG. It is a top view of the conveying apparatus containing a drive part. It is a member disassembled perspective view of an inner frame group. (A) is a plan view of the inner frame set, and (B) is a bottom view. (A) is a side view of the release position of the cam for the conveyance pressing roller shown by the arrow IX-IX in FIG. 8 (A), and (B) is a side view of the non-release position of the cam. It is sectional drawing of the printer part of a double-sided printing state. It is a perspective view of a release rod and a side plate. (A) is a side cross-sectional view of the release rod and the side plate in the non-release posture indicated by the XIIA-XIIA line in FIG. 6, and (B) is a side cross-sectional view of the release rod and the side plate in the same release posture. FIG. 7A is a view showing a release rod in a release posture shown in the same cross section as FIG. 6, and FIG. 7B is a cross-sectional view of a platen and the like in the same release posture.

  In the following, as a preferred embodiment of the image forming apparatus of the present invention, a multifunction machine 10 of FIG. 1 having a scan / print / copy / fax function will be described. The height direction (Z-axis direction) of the multi-function device 10 formed in the shape of a rectangular parallelepiped is defined as the vertical direction, and the depth direction (Y-axis direction) is defined as the front-rear direction (note that the front or front side is described later) The rear side or back side means the side having the U-turn path described later), and the width direction (X-axis direction) is defined as the left-right direction (see FIG. 1), will be described below.

[Outline of MFP 10]
The multifunction machine 10 includes a printer housing 11, a scanner housing 12 placed on the upper surface of the printer housing 11, and a document cover 13 placed on the upper surface of the scanner housing 12. The document cover 13 is supported by the scanner housing 12 so that it can be opened and closed. The original image is scanned and captured by a scanner (not shown) such as a flatbed scanner accommodated in the scanner housing 12. The scanner housing 12 that houses the scanner is supported by the printer housing 11 so that it can be opened and closed.

  The printer housing 11 includes a recess 11a for accommodating the paper feed cassette 14 at the lower portion, and supports the paper feed cassette 14 so that it can be pulled out. The paper feed cassette 14 is pulled out from the opening 11b on the front surface of the printer housing 11 by the user, and the first transport medium 19 such as paper is placed thereon. An image is recorded on the first transported medium 19 by the printer unit 15 housed in the printer housing 11.

Control of the printer unit 15 and the above-described scanner is performed by the control unit. The control unit is realized by various electronic components such as a microcomputer mounted on the control board. Signals are input to the control unit from the operation panel 16 in FIG. 1 mounted on the printer housing 11 or an external device such as a personal computer. The control unit drives the scanner or captures the image by the input signal. An image is sent to a personal computer or a telephone line, or an image captured by a scanner or an image input from a personal computer or a telephone line is recorded on the first transported medium 19 or the second transported medium. The second recording medium is a CD or DVD, and is placed on a tray (not shown). The tray is formed in a plate shape having a thickness of several millimeters including a circular recess into which the second transport medium is fitted, for example. The tray is placed by a user on a later-described tray guide (not shown) included in the printer unit 15.

[Printer unit 15]
As shown in FIG. 2, the printer unit 15 includes a paper feed unit 41 that feeds the first transport medium 19 from the paper feed cassette 14 to the U-turn path 32, and a first transport target from the U-turn path 32. The first conveying path 31 and conveying means 30 for conveying the medium 19 through the recording unit 20 in the paper discharge direction, the recording unit 20 for forming an image on the conveyed medium to be conveyed, and duplex printing on the first conveyed medium 19 A reverse conveyance path 34 (second conveyance path in the claims) that conveys the first conveyed medium 19 to the terminal portion of the U-turn path 32 when performing double-sided image formation. The first transport path 31 is a forward path for duplex printing (double-sided image formation), and the reverse transport path 34 (second transport path) is also a return path.
The transport unit 30 directly transports the first transport medium 19 as described later, and transports the second transport medium together with the tray. The first transport medium 19 and the tray correspond to the transport medium described in the claims.

[Recording section 20 (recording section referred to in claims)]
The recording unit 20 includes a plate-like platen 22 disposed above the rear portion of the paper feed cassette 14, a recording head 21 disposed above the platen 22, and a carriage provided with the recording head 21 on the lower surface. 17 is provided with a pair of rail bodies 23a and 23b that slidably support 17 in the left-right direction, and a main frame 24 that supports the pair of rail bodies 23a and 23b.

[Recording head 21]
The recording head 21 includes a nozzle having a discharge port that opens downward, and the nozzle is deformed by a piezoelectric element or the like to discharge ink droplets from the discharge port toward the lower platen 22. As will be described later, the first transport medium 19 and the tray are transported on the platen 22. By transporting the first transport medium 19 and the tray and the movement of the recording head 21 in the left-right direction, the printer unit 15 prints an image on almost the entire surface of the first transport medium 19 and the second transport medium. Can be recorded. The recording head 21 forms a part of a first transport path 31 to be described later together with the platen 22 and is also a part of the transport unit 30. The platen 22 will be described later.

[Paper Feeding Unit 41]
As shown in FIG. 2, the sheet feeding means 41 is disposed above the rear portion of the sheet feeding cassette 14, and includes a support shaft 42, an arm 43, and a sheet feeding roller 44 at the tip thereof. The support shaft 42 is supported by a flat surface portion 24a, which is the bottom of the main frame 24, so as to be rotatable about its central axis, and is rotated by a drive unit 26 disposed outside the right side plate 25a. The arm 43 has a configuration in which a plurality of transmission gears (not shown) for transmitting the rotation of the support shaft 42 to the paper feed roller 44 are provided. The paper feed roller 44 comes into contact with the first transported medium 19 placed on the paper feed cassette 14 when the arm 43 rotates around the support shaft 42, and the paper feed roller 44 rotates when the support shaft 42 rotates. By rotating, the first transport medium 19 is sent out to the first transport path 31 via the U-turn path 32 described below.

[Mainframe 24]
As shown in FIG. 2, FIG. 3, FIG. 6 and the like, the main frame 24 includes a flat portion 24a positioned below the support shaft 42 and side plates 25a and 25b which are vertically provided from both left and right sides of the flat portion 24a. And is fixed to the printer housing 11. Between the upper ends of the side plates 25a and 25b, the pair of rail bodies 23a and 23b described above are supported and fixed. Further, both ends of the inner frame 29 described later are fixed to the inner surfaces of the side plates 25a and 25b below the pair of rail bodies 23a and 23b and above the flat portion 24a by screwing or caulking. Yes. The main frame 24 and the inner frame 29 are made of sheet metal made of a metal plate. Between the side plates 25a and 25b, the platen 22 is disposed and fixed at a position above the inner frame 29. Thus, since the inner frame 29 is fixed to the pair of side plates 25a and 25b in the vertical space between the plane portion 24a and the first transport path 31, the main frame 24 is connected to the plane portion 24a and the inner frame 29. Since the pair of side plates 25a and 25b form a frame having a rectangular cross section, the rigidity of the entire frame structure including the main frame 24 can be increased.

  A maintenance section (not shown) is disposed outside the right side plate 25a, and here is a maintenance position that also serves as a standby position for the recording head 21. At the maintenance position also serving as the standby position, the cap portion in the maintenance portion covers the nozzle surface of the recording head 21 from below. A right drive unit 26 having a drive motor and a transmission mechanism arranged outside the right side plate 25a operates a suction pump (not shown) to selectively suck ink from the nozzles, or not shown on the recording head 21. A recovery process is performed to remove bubbles in the buffer tank. An ink receiving portion (not shown) is disposed outside the left side plate 25b when viewed from the feeding direction of the first transported medium 19. The recording head 21 periodically discharges ink to prevent nozzle clogging during a recording operation at a flushing position provided in the ink receiving portion, and receives ink at the ink receiving portion.

  Outside the left side plate 25b is disposed a PF driving unit 27 in which a conveyance driving roller 35a, a sheet discharge driving roller 36a, a PF motor 27a for rotating and driving a switchback driving roller 37a, and a transmission mechanism 27b thereof are arranged. Has been. The PF frame 27c that supports the PF motor 27a and its transmission mechanism 27b is suspended and supported by the rail bodies 23a and 23b and fixed to the left side plate 25b (see FIG. 6).

[Inner frame 29]
The inner frame 29 is close to the first surface 29a near the U-turn path 32 that conveys the first transported medium 19 from the paper feed cassette 14 to the recording unit 20 (below the recording head 21), and close to the recording head of the recording unit. A second surface 29b positioned above the first surface 29a is provided, and the first surface 29a and the second surface 29b made of sheet metal are connected by a vertical connecting plate 29c. At the rear end of the first surface 29a, a rear end plate 29d (an end portion in the claims) that is also vertically upward is provided. A front end plate 29e that is vertically upward is also provided at the front end of the second surface 29b. These are formed by bending by press working (see FIG. 7 and the like).

  A first transport path 31 is disposed above the inner frame 29, and a reverse transport path 34 as a second transport path is disposed below. The inner frame 29 is provided with a plurality of constituent members to be described later in the first conveyance path 31 and the reverse conveyance path 34 which is the second conveyance path. That is, the first end 29a of the inner frame 29 and the rear end plate 29d, which is the end portion bent upward from the first surface 29a, are configured as a conveying presser roller holder 35b as a constituent member and the upper end side of the U-turn path 32. The inner guide block 71 is held, and the constituent member including at least the backward conveyance follower roller 73 in the reverse conveyance path 34 is fixed on the second surface 29b (see FIGS. 7 and 8). These components are assembled in advance before the inner frame 29 is assembled into the main frame 24.

More specifically, a shaft portion 75 at the rear end portion of the presser holder 33 in which a plurality of conveying press rollers 35b are arranged in parallel at the front end is supported by a bearing portion 76 formed by bending on the rear end plate 29d of the inner frame 29. Yes. Inner guide block 71 The inner guide block 71 is attached to an engaging portion 77 formed in the rear end plate 29d so as to cover the bearing portion 76 (see FIG. 7). Therefore, the main frame 24 having two transport paths (the first transport path 31 and the reverse transport path 34) in the vertical direction can be made compact, and the rigidity of both the main frame 24 and the inner frame 29 can be increased. And since the some structural member in the inversion conveyance path 34 which is the 1st conveyance path 31 and the 2nd conveyance path is previously assembled | attached to the inner frame 29, the arrangement | positioning precision between several structural members is high. Become.

  Since the reverse conveyance path 34 is disposed in a rectangular cross-section frame surrounded by the flat portion 24a, the inner frame 29, and the pair of side plates 25a and 25b, the arrangement of the reverse conveyance path 34 is further stabilized. , Position accuracy is also increased.

  Since both end portions of the inner frame 29 in a state where the plurality of constituent members are assembled in advance are fixed to the inner surfaces of the side plates 25a and 25b by screwing or caulking, the inner frame 29 is Compared with the sequential assembly of a plurality of constituent members after attachment, the number of steps is significantly reduced, and quick and accurate assembly becomes possible.

  The inner frame 29 has a first surface 24a close to the U-turn path 32 for transporting the medium to be transported from the paper feed cassette 14 to the recording unit, and a second surface positioned near the recording head of the recording unit and above the first surface 24a. Since the surface 24b is provided, it is easy to arrange the reverse conveyance path 34 in a downward inclined manner toward the U-turn path 32. Since the first surface 24a and the second surface 24b are connected by the connecting plate 29c or have a bent portion such as the rear end plate 29d or the front end plate 29e, the rigidity of the inner frame 29 itself is high. It can be further enhanced.

[First transport path 31]
As shown in FIG. 2, the first conveyance path 31 includes the recording head 21 and the platen 22 described above, a conveyance roller pair 35 disposed near the rear end of the platen 22, and the front end of the platen 22. A pair of paper discharge rollers 36 disposed in the front and a pair of switchback rollers 37 (hereinafter referred to as switchback SB) disposed in front of the paper discharge roller pair 36 are formed in a straight section. The lower end of the U-turn path 32 located behind the platen 22 is positioned above the rear end portion of the paper feed cassette 14, and the rear end portion of the first conveyance path 31 is positioned at the upper end of the U-turn path 32. The first transport path 31 is also referred to as a transport forward path. The first transport path 31 and a second transport path (reverse transport path 34), which will be described later, include a flat portion 24a that supports the paper feeding means 41, and a pair of side plates 25a and 25b that rise from the left and right sides of the flat portion 24a. Surrounded by a main frame 24.

[Conveying roller pair 35]
The conveyance roller pair 35 disposed near the rear end of the platen 22 is composed of an upper conveyance driving roller 35a and a conveyance pressing roller 35b which is a driven roller facing the lower side, and also has a resist function. . The upper conveyance drive roller 35a is supported by the main frame 24 so as to be rotatable about its central axis, and is rotated by the PF drive unit 27 described above. The conveyance pressing roller 35b is integrated with the platen 22 and contacts the upper conveyance driving roller 35a so that the conveyance medium can be nipped and conveyed, and the conveyance pressing roller 35b is lowered with respect to the conveyance driving roller 35a. It moves between a release posture in which the first conveyance path 31 is expanded (released). That is, the conveyance roller pair 35 has a configuration in which the first conveyance path 31 can be expanded in the vertical direction.

[Reverse conveying path 34 (second conveying path in claims)]
The reverse conveying path 34 conveys the first conveyed medium 19 when performing double-sided printing on the first conveyed medium 19 to the lower side of the recording head 21 again with the front and back thereof reversed. And is also referred to as a transport return path. The reverse conveyance path 34 is disposed between the flat portion 24 a of the main frame 24 and the inner frame 29. The reverse conveyance path 34 is disposed in an inclined manner so as to be a high position on the SB roller pair 37 side to be described later and a low position on the U-turn path 32 side. In other words, the first conveyance path and the second conveyance path are formed at an angle so that their respective planes intersect at the downstream side in the conveyance direction of the medium to be conveyed, and from the paper feed cassette 14 to the recording unit 20. On the side close to the U-turn path 32 that transports the medium to be transported, an inner guide block 71 that connects the first transport path and the second transport path up and down is provided. Furthermore, in other words, a plurality of structural members of the first transport path and the second member are formed in a substantially triangular space surrounded by the respective planes of the first transport path and the second transport path and the inner guide block 71 of the U-turn path 32. A plurality of constituent members in the conveyance path are arranged, and the inner frame 29 is arranged in the triangular space. As a result, the positional relationship between the two conveying paths can be reliably maintained while ensuring the rigidity of the frame structure.

  Hereinafter, the configuration of the reverse conveyance path 34 will be described. A lower constituent member and an upper constituent member (both made of synthetic resin) sandwiching the passage of the first transport medium 19 are provided. The lower component member includes a first inclined guide member 34a fixed to the main frame 24 below the inner frame 29, and a second inclined guide member 34b adjacent to the U-turn path 32 behind the first inclined guide member 34a. And a third inclined guide member 34c that is pivotally supported by a shaft of an SB drive roller 37a, which will be described later, in front of the first inclined guide member 34a (FIGS. 2, 5, and 10). reference). The upper component member includes a lower surface of the platen 22 and an upper conveyance guide member 74 attached to the lower surface of the inner frame 29. The return roller pair 38 includes a return drive roller 38a attached to the first inclined guide member 34a and a return driven roller 38b provided at the front end portion of the upper conveyance guide member 74 (FIGS. 2, 5, and 5). 7, see FIG.

  By arranging the intermediate guide block 70 at the upper part of the U-turn path 32 and between the outer guide block 69 and the inner guide block 71, the U-turn path 32 is configured so that the first transport medium 19 is fed into the paper feed cassette 14. And the path transported from the reverse transport path 34 merge.

  The inner frame 29 has the first surface 29a and the rear end plate 29d (end portion) bent upward from the first surface 29a to hold the conveyance pressing roller holder 33 in the constituent members and the inner guide block 71 of the U-turn path 32. Then, the upper conveyance guide member 74, which is a constituent member including at least the return path driven roller 38b in the reverse conveyance path 34, is held by the second surface 29b.

  By energizing the press holder 33 upward by the first coil spring 45 shown in FIGS. 5 and 9B standing on the inner frame 29, the transport press roller 35b is pressed against the transport drive roller 35a.

  The structure for releasing the conveyance presser roller 35b includes a cylindrical restraining piece 46 that protrudes downward from the front end portion of the presser holder 33 and is juxtaposed in plural, a presser shaft 47 inserted through the cylindrical restraint piece 46, and a presser shaft. 47, and a regulating portion 49 formed by cutting and raising the top surface of the inner frame 29 (see FIGS. 7 and 9). When the presser shaft 47 is rotated by a predetermined rotation angle by the rotational force from the right drive unit 26, the peripheral surface of the cam 48 presses the restricting portion 49, and the presser shaft 47 is lowered by a predetermined dimension (see FIG. 9A). ). Accordingly, the lower side of the cylindrical restraining piece 46 is pushed down by the rotation of the presser shaft 47, so that the transport press roller 35b is separated from the transport drive roller 35a and assumes a release posture. From this state, when the presser shaft 47 is further rotated by a predetermined rotation angle, the peripheral surface of the cam 48 is separated from the restricting portion 49 (see FIG. 9B). The presser holder 33 is turned upward by the upward biasing force of the first coil spring 45, and the transport press roller 35b is brought into a non-release posture in contact with the transport drive roller 35a.

[Discharge roller pair 36]
The paper discharge roller pair 36 disposed near the front end of the platen 22 is composed of a lower paper discharge driving roller 36a and an upper paper discharge driven roller 36b. The paper discharge driven roller 36b is a spur type and is supported by the main frame 24 so as to be rotatable about its central axis.

  The paper discharge driving roller 36a has a non-release posture supported by a later-described release rod 50 and contacting the paper discharge driven roller 36b, and a release posture supported by the main frame 24 at a position below the non-release posture. It is provided so as to be movable in the vertical direction. Specifically, the support shaft 36c of the paper discharge driving roller 36a is passed through a long hole 58a that is long in the vertical direction provided in the left and right side plates 25a and 25b, and abuts against the lower peripheral wall of the long hole 58a in the release posture. And supported by the main frame 24. Further, in a non-release posture in which the paper discharge driving roller 36a is in contact with the paper discharge driven roller 36b, the paper discharge driving roller 36a is urged upward by a second coil spring 62 described later and pressed against the paper discharge driven roller 36b. The paper discharge drive roller 36a is rotated by the PF drive unit 27 described above.

[Platen 22]
Both left and right end portions of the front end portion of the plate-like platen 22 are supported by a support shaft 36c of the paper discharge driving roller 36a, and the front portion can move in the vertical direction together with the paper discharge driving roller 36a. The rear part of the platen 22 is also provided so as to be movable in the vertical direction as will be described later.

  Attachment portions to which the spring holders 54 are attached are provided near the rear portions of the left and right ends of the platen 22. The spring holder 54 is provided at a holder portion disposed below the attachment portion, a pair of front and rear attachment pieces projecting from the front and rear end portions of the holder portion toward the upper attachment portion, and a tip portion of the attachment piece. And a hooking claw that hooks onto the mounting portion. The spring holder 54 moves in the vertical direction with respect to the platen 22 with the position where the hooking claw is hooked on the mounting portion as the lower limit position. A second coil spring 52 is disposed between the holder portion of the spring holder 54 and the mounting portion of the platen 22 (see FIG. 5B). The second coil spring 52 urges the attachment portion upward with respect to the holder portion. The holder portion is supported by the release rod 50 as will be described later, whereby the rear portion of the platen 22 is supported by the spring holder 54 while being biased upward by the second coil spring 52. As will be described later, when the release rod 50 is moved by the user and the spring holder 54 loses support by the release rod 50, the rear portion of the platen 22 is lowered by its own weight together with the front portion, and is supported by the main frame 24 in the release posture. The vertical movement distance of the platen 22 is set to be substantially the same as the thickness dimension of the tray. Therefore, when the platen 22 is in the release posture, the tray can be transported by the transport roller pair 35 and the discharge roller pair 36.

[SB roller pair 37]
As shown in FIG. 2, the SB roller pair 37 disposed in front of the platen 22 includes an upper SB driven roller 37b and a lower SB drive roller 37a. The upper SB driven roller 37b is a spur type that is supported on the main frame 24 or the like so as to be rotatable about its central axis. The lower SB drive roller 37a is supported by a later-described release rod 50 so as to be rotatable about its central axis, and is rotated by the PF drive unit 27 described above (see FIG. 7B). The SB drive roller 37a is supported by a later-described release rod 50 so as to be movable in the vertical direction. It moves along the up-down direction between the non-release posture in contact with the upper SB driven roller 37b and the release posture positioned below the non-release posture. The vertical movement distance of the SB driving roller 37a is set so that the separation dimension between the SB driving roller 37a and the SB driven roller 37b is equal to or larger than the thickness dimension of the tray.

  The support shaft 37c of the SB drive roller 37a has one end of each of the left and right ends passing through a long hole 58b that is long in the vertical direction of each side plate 25a, 25b. Each abuts. The torsion coil spring is supported at the center and the other end by the main frame 24, and urges the support shaft 37c upward by the one end. When the support shaft 37c is biased upward by the torsion coil spring 63, the SB driving roller 37a in the non-release posture is pressed against the SB driven roller 37b. The SB drive roller 37a pressed by the SB driven roller 37b is rotated by the drive unit described above to convey the first conveyed medium 19. The SB drive roller 37a is fed to the paper discharge unit 14a provided to cover the upper surface of the paper feed cassette 14 by carrying the first carried medium 19 forward during single-sided printing. Discharge. When the upstream end of the first transport medium 19 in the transport direction comes to the position of the SB roller pair 37, the SB drive roller 37a is temporarily stopped. Next, the SB driving roller 37 a is rotated in the reverse direction, and the first transported medium 19 is transported backward, thereby transporting the first transported medium 19 to the reverse transport path 34. The first transported medium 19 that has entered the reverse transport path 34 is returned from the U-turn transport path 32 to the first transport path 31, passes over the platen 22 with the front and back reversed, and an image is formed on the back surface. Thus, double-sided image formation (double-sided printing) can be performed.

[Release rod 50]
As shown in FIGS. 3, 5, and 12, the release rod 50 as an example of the release means includes base portions 51 that are respectively formed in a plate shape whose thickness direction is the left-right direction. The pair of left and right release rods 50 are respectively disposed between the platen 22 and the inner side surfaces of the left and right side plates 25a and 25b in the main frame 24 in the left and right direction, and are movable in the front and rear direction along the inner side surfaces of the left and right side plates 25a and 25b. Supported by

  As will be described later, the release rod 50 includes a guide groove hole 53 formed in the front portion of the base portion 51, an inverted T-shaped dovetail groove 55 formed in the rear portion of the base portion 51 and opened upward, and a base portion 51. And a support piece 56 extending rearward from the rear end. The configuration in which each release rod 50 is supported so that it can move back and forth and cannot fall down is formed by bending pieces 64 that are cut and raised on the inner side surfaces of the left and right side plates 25a and 25b and have a horizontal portion, and the inner frame 29 or the side plates 25a and 25b. The guide frame 65 is cut and raised on the inner surface and the support piece 56 is inserted, and the support surface 66 on the upper surface of the inner frame 29 on which the support piece 56 is slidably supported (see FIG. 11). Accordingly, the release rod 50 is supported by the left and right side plates 25a and 25b and the inner frame 29 so as to be movable in the front-rear direction, and the support piece 56 is inserted into the inner diameter portion of the guide frame 65, whereby the release rod 50 is inserted into the side plate 25a. , 25b can be prevented from falling in the direction away from it.

  At the front end of the release rod 50, a holding portion 50a that is opened downward is formed. When the first transport medium 19 is jammed in the first transport path 31 or the reverse transport path 34 (when a paper jam occurs), the user removes the paper feed cassette 14 from the opening 11b. Next, by putting a hand into the widely opened recess 11a, grasping the grip portion 50a of at least one of the left and right release rods 50, and pulling the release rod 50 forward, the first transport path as will be described later. 31 can be expanded to handle paper jams.

  Note that in an image forming apparatus capable of forming an image on the second transport medium, a tray guide (not used) for feeding a tray on which the second transport medium, which is a CD or a DVD, is placed to the first transport path 31 is used. Since it is connected to the grip 50a at the front end of the left and right release rod 50, it has a configuration that can be moved in the front-rear direction between a rear initial posture and a front expanded posture. In other words, the release rod 50 moves in conjunction with the operation to make the tray ready for placement. The initial posture corresponds to a non-release posture, and the extended posture corresponds to a release posture.

  Hereinafter, a configuration in which the release rod 50 supports the SB drive roller 37a so as to be movable will be described. As shown in FIG. 11, guide groove holes 53 through which the left and right ends of the support shaft 37c of the SB drive roller 37a are passed are provided in the front portion of the base 51 of the release rod 50, respectively. The guide groove 53 includes an open portion 53a that is open upward, an inclined portion 53b that is provided behind the open portion 53a, and a linear portion 53c that is provided behind the inclined portion 53b. An inclined surface 53d, which is the upper peripheral surface of the inclined portion 53b, is inclined so as to be lowered toward the rear. The inclined surface 53d is formed by, for example, one or more planes or curved surfaces. In the illustrated example, the inclined surface 53d is formed of substantially one plane. The linear portion 53c extends linearly from the inclined portion 53b toward the rear. As shown in FIGS. 11 and 12A, the guide groove 53 is provided at a position where the SB driving roller 37a is at the front end of the inclined portion 53b when the release rod 50 is in the rear non-release posture. It has been. When the release rod 50 is in the non-release posture, the SB drive roller 37a urged upward by a torsion coil spring (not shown) is pressed against the SB driven roller 37b and the upper inclined surface 53d. As shown in FIGS. 12B and 13, when the release rod 50 moves from the non-release posture toward the front (release posture), the SB drive roller 37a pressed against the inclined surface 53d by the torsion coil spring. Is pushed down while being in sliding contact with the inclined surface 53d, and reaches the linear portion 53c as shown in FIG. That is, the SB drive roller 37a changes its posture from the non-release posture to the release posture.

  Next, a configuration in which the release rod 50 moves the paper discharge driving roller 36a will be described. Each base 51 of the release rod 50 is provided with an inverted T-shaped dovetail groove 55 opened upward as shown in FIGS. 11, 12A, and 12B. The dovetail groove 55 is provided at a position directly below the support shaft 36c of the paper discharge drive roller 36a when the release rod 50 is in the initial posture. A spring holder 61 is accommodated in each dovetail groove 55. The spring holder 61 is provided at a holder portion disposed at the upper portion of the dovetail groove 55, a pair of front and rear mounting pieces projecting downward from both front and rear end portions of the holder portion, and a lower end portion of the mounting piece. And a hooking claw that is hooked on the peripheral wall at the bottom of the dovetail 55. The spring holder 61 moves in the vertical direction with respect to the base 51 with the position at which the hooking claw is hooked on the peripheral wall of the dovetail groove 55 as the upper limit position. A second coil spring 62 is disposed between the holder portion disposed on the top of the dovetail 55 and the inner bottom surface (lower surface) of the dovetail 55. The spring holder 61 is biased upward with respect to the base 51 by the second coil spring 62.

  As shown in FIG. 5B, when the release rod 50 is in the non-release posture, the support shaft 36 c of the paper discharge driving roller 36 a comes into contact with the upper surface of the holder portion of the spring holder 61, and the spring holder 61. Is located below the upper limit position. When the release rod 50 is in the initial posture, the paper discharge drive roller 36a is biased upward by the second coil spring 62 via the spring holder 61, and the transport roller 36a is pressed against the paper discharge driven roller 36b.

  Since the spring holder 61 is attached to the base 51 of the release rod 50 as described above, it slides in the front-rear direction integrally with the base 51. Here, at the rear part of the holder part of the spring holder 61, an inclined surface is provided that descends toward the rear. When the release rod 50 in the initial posture is moved forward, the support shaft 36c of the paper discharge drive roller 36a slides on the inclined surface and comes off the spring holder 61. The support shaft 36c that has lost support by the spring holder 61 is lowered downward by its own weight and is supported by the left and right side plates 25a and 25b.

Next, a configuration in which the release rod 50 changes the posture of the rear portion of the platen 22 will be described. As shown in FIGS. 11 and 13, the release rod 50 includes a support piece 56 that extends rearward from the rear end of the base 51. At the rear end of the support piece 56, as shown in FIG. 5B, when the release rod 50 is in the non-release position, the holder of the spring holder 54 is attached to the attachment portion of the platen 22. The support convex part which contacts the lower surface of a part is provided. That is, the release rod 50 supports the rear portion of the platen 22 through the spring holder 54 by the support piece 56. An inclined surface 56 b is provided at the rear of the support convex portion of the support piece 56. The inclined surface 56b is inclined so as to be lowered toward the rear. As shown in FIGS. 12A to 12B, when the release rod 50 moves forward from the initial posture, the spring holder 54 moves downward while sliding on the inclined surface 56b. As shown to (A), it remove | deviates from a support convex part. When the spring holder 54 is detached from the support convex portion, the platen 22 is lowered by its own weight and assumes a release posture.

[Operation]
The non-release posture of the release rod 50 is a posture for forming (recording) an image on the first transported medium 19 placed on the paper feed cassette 14. When the pair of release rods 50 are in the initial posture, the conveyance press roller 35b is pressed by the conveyance drive roller 35a, the discharge drive roller 36a is pressed by the discharge driven roller 36b, and the SB drive roller 37a is Pressed by the SB driven roller 37b, the platen 22 is in a non-release posture separated from the recording head 21 by a predetermined distance (printing gap). In the case where the release rod 50 is in the non-release posture, when the formation of an image on the first transported medium 19 is instructed, the control unit described above rotates the paper feed roller 41 and places it on the paper feed cassette 14. The first transported medium 19 is sent out to the U-turn transport path 32. The sent first transported medium 19 is drawn into the first first transport path 31 by the transport roller pair 35 and is transported by the transport roller pair 35 and the paper discharge roller pair 36 by the recording head 21 on one or both sides. An image is formed on the sheet, and is discharged to the sheet discharge portion 14a on the sheet cassette 14 by the SB drive roller 37a.

  The release posture of the release rod 50 is a posture for forming an image on a second transported medium such as a CD or a DVD. When the tray guide is pulled forward by the user and the pair of release rods 50 change from the initial posture to the release posture (expanded posture), a plurality of members (parts) constituting the lower side (one side) of the first conveyance path 31. The platen 22, the paper discharge drive roller 36a, and the SB drive roller 37a move downward at a stroke. When the formation of an image on the second transport medium is instructed, the control unit rotates the presser shaft 47 by a predetermined angle, lowers the transport press roller 35b as described above, and the transport drive roller 35a. Increase the interval between and. As a result, the first conveyance path 31 is expanded in the vertical direction. The tray on which the second transport medium is placed is inserted between the paper discharge roller pair 36 by the user while being supported by the tray guide. When the formation of an image on the second transport medium is instructed, the control unit described above rotates the paper discharge driving roller 36a and the transport press roller 35b to transport the tray backward, and then the transport press roller. 35b, the paper discharge drive roller 36a is rotated in the reverse direction to convey the tray forward. An image is formed on the second transport medium by the recording head 21 while the tray passes over the platen 22.

  When a paper jam occurs in the first transport path 31 or the reverse transport path 34, the user pulls out the paper feed cassette 14 from the printer housing 11, and secures a space for the user's hand to enter the recess 11a. When a user's hand is put into the recess 11a and at least one of the left and right release rods 50 is gripped and pulled forward, a plurality of parts constituting the lower side (one side) of the first conveyance path 31 described above are formed. In the platen 22, which is a member (part), the paper discharge driving roller 36a, and the SB driving roller 37a, the above-mentioned released portion moves at least all at once. Thus, since the 1st conveyance path 31 is expanded, the 1st to-be-conveyed medium 19 used as jam can be extracted easily. Even when only the conveyance pressing roller 35b is in the released state, the paper jam processing is easy.

When the release rod 50 in the extended posture is returned to the non-released posture by the user, the conveyance pressing roller which is a plurality of members (parts) constituting the lower side (one side) of the first conveyance path 31 by the reverse action to that described above. 35b, platen 22, paper discharge drive roller 36a, SB drive roller 37a The support shaft 37c of the SB drive roller 37a moves upward while sliding on the inclined surface 53D by the urging force of the torsion coil spring 63, and the support convex of the support piece 56 The part sinks under the holder part and pushes up the spring holder 54, and the spring holder 61 sinks under the spindle 36c of the paper discharge drive roller 36a and pushes up the spindle 36c. That is, the SB drive roller 37a, the platen 22, and the paper discharge drive roller 36a can be returned to the non-release posture all at once.

  The front end of the movable guide member 34b in front of the main inclined guide member 34a fixed to the main frame 24 is connected to the support shaft 37c of the SB drive roller 37a, and the rear end of the movable guide member 34b is free. When the paper feed cassette 14 is pushed into the recess 11a, the pressing portion 14b protruding upward at the front end portions on both the left and right sides of the paper feed cassette 14 pushes up the lower rear end portion of the movable guide member 34b. Thus, since the rear end of the movable guide member 34b is in an inclined posture in which the rear end of the movable guide member 34b is slightly above the front end of the main inclined guide member 34a (see FIG. 5A), the first conveyed medium to be conveyed in reverse 19 is smoothly conveyed on the reverse conveying path 34. When the sheet feeding cassette 14 is pulled out, the restraint of the movable guide member 34b by the pressing portion 14b is released, and as shown in FIG. 13B, the rear end of the movable guide member 34b is suspended and supported. Paper jam processing in the reverse conveyance path 34 is facilitated.

  In the present invention, an image forming apparatus including one of the right and left release rods 50 may be used. Further, the conveyance pressing roller 35b may be included as a member constituting the lower side (one side) of the first conveyance path 31.

19. First transport medium (transport medium)
20 ... Recording part 22 ... Platen 24 ... Main frame 24a ... Flat part 25a, 25b ... Side plate 29 ... Inner frame 29a ... First surface 29b ... Second surface 29c ... Rear end plate 30 ... Transport means 31 First transport path 32 U-turn path 33 Presser holder 34 Reverse transport path (second transport path)
35 ... Conveyance roller pair 35a ... Conveyance drive roller 35b ... Conveyance driven roller 37 ... SB roller pair 37a ... SB drive roller 37b ... SB driven roller 71 ... Inner guide block

Claims (3)

A paper feed unit that feeds the transported medium one by one from the lower paper feed cassette in the apparatus main body to the recording unit, a recording unit that forms an image on the transported medium, and a second of the transported medium that passes through the recording unit. An image forming apparatus comprising: 1 transport path; and a second transport path for forming a double-sided image on a transported medium after passing through the recording unit,
The two conveyance paths are surrounded by a main frame including a flat portion that supports the paper feeding unit and a pair of side plates that rise from both the left and right sides of the flat portion,
An inner frame is fixed to the pair of side plates above the flat portion,
The first transport path is disposed above the inner frame, and the second transport path is disposed below,
The first transport path and the second transport path are formed at an angle so that their respective planes intersect at the downstream side in the transport direction of the transported medium, from the paper feed cassette to the recording unit An image forming apparatus, wherein an inner guide block that connects the first transport path and the second transport path vertically is provided on a side close to a U-turn path for transporting a transported medium. A plurality of constituent members of the first transport path and the second transport are disposed in a substantially triangular space surrounded by the respective planes of the first transport path and the second transport path and the inner guide block of the U-turn path. A plurality of components in the road are arranged,
The image forming apparatus according to claim 1, wherein the inner frame is disposed in the triangular space. The inner frame has a first surface close to a U-turn path for transporting a medium to be transported from the paper feed cassette to the recording unit, and a second surface located near the recording head of the recording unit and above the first surface. And the first surface and the second surface are connected to each other,
The first surface of the inner frame holds a conveyance pressing roller holder in a component of the first conveyance path and an inner guide block of the U-turn path, and the second surface of the inner frame has a position in the second conveyance path. The image forming apparatus according to claim 1, wherein a constituent member including at least a backward conveyance driven roller is held.

Images