JP2006051779A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can support a winding member by a torque limiter stably and rotatably without increasing a part count and a working time. <P>SOLUTION: In the thermal transfer printer (image forming apparatus), the winding member includes a reel engaging part 3a (engaging part) to engage with a film storage member 2, a body 3b formed of resin which is engaged with the reel engaging part 3a and integrally rotates with the reel engaging part 3a, and the torque limiter 3c set at the body 3b. Moreover, the thermal transfer printer is equipped with a clutch spring 4 (coil spring) for suppressing rotation in a reverse direction of the winding member 3. A chassis 1 formed of a metal has a first bearing 1e which supports a first axle 3l of the body 3b of the winding member 3 rotatably. A motor bracket 9 formed of a metal has a second bearing 9a which supports a second axle 3m of the body 3b of the winding member 3 rotatably. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, various types of bearing structures that rotatably support a rotating shaft or the like have been proposed in an image forming apparatus or the like (see, for example, Patent Documents 1, 2, and 3).

  In Patent Document 1, a bearing that protrudes in a cylindrical shape by burring is formed on a bearing forming protrusion of a metal chassis, and the bearing forming protrusion on which the bearing is formed is bent by 90 °. A bearing structure is disclosed in which a metal lead screw is disposed in parallel to the chassis and is rotatably supported.

  Further, in Patent Document 2, a plastic gear fixed to a shaft portion of a paper feed roller by a screw can be rotated by forming a bearing protruding in a cylindrical shape by burring on a metal chassis. A structure including one bearing to support is disclosed.

  Further, in Patent Document 3, a shaft of a feed roller that faces a separation member and separates and feeds one by one from a plurality of documents is provided with two bearing members on a feed unit (chassis). A document feeder is disclosed that is rotatably mounted via a webbing and can be rotated and detachably mounted on two resin-made support members (bearings) having elastically deformable openings. .

  Conventionally, a printer (image forming apparatus) including a reel base (winding member) having a torque limiter is known (see, for example, Patent Document 4). Patent Document 4 discloses a printer (image forming apparatus) that winds an ink ribbon (film) by a reel base (winding member) having a torque limiter mechanism rotatably attached to a support shaft provided in a chassis. Has been.

  Conventionally, an image forming apparatus such as a thermal transfer printer including a winding member having a torque limiter is known. Here, the torque limiter refers to a mechanism having a function capable of interrupting transmission of torque exceeding a predetermined value. With this torque limiter, it is possible to reduce the load on the driven side of the device by preventing the torque generated on the driving side from being transmitted to a driven side downstream from the torque limiter. is there. In a conventional thermal transfer printer, a film for thermal transfer stored in a film storage member is wound using a winding member having such a torque limiter.

  FIG. 8 is a perspective view showing the overall configuration of a conventional thermal transfer printer. 9 to 12 are diagrams for explaining a detailed structure of a winding member of a thermal transfer printer according to a conventional example. The structure of a conventional thermal transfer printer will be described with reference to FIGS.

  As shown in FIGS. 8 and 10, a conventional thermal transfer printer performs printing with a metal chassis 101, a film storage member 102, a winding member 103, and a bearing member 104 (see FIG. 10). For this purpose, a thermal head 105, a motor bracket 106, a motor 107, a rubber paper supply / discharge roller 108, a paper supply / discharge roller gear 109, and a plurality of intermediate gears 110 are provided.

  Further, as shown in FIG. 8, the chassis 101 has one side surface 101a and the other side surface 101b. Further, the motor bracket 106 described above is attached to one side surface 101 a of the chassis 101. As shown in FIG. 9, the film storage member 102 includes a reel 102a provided with a recess 102b having three grooves 102c, and a thermal transfer film 102d wound around the outer peripheral surface of the reel 102a.

  Further, as shown in FIGS. 9 and 10, the winding member 103 includes a metal rotating shaft 103a, a resin reel engaging portion 103b attached to one end of the rotating shaft 103a, and a rotating shaft 103a. Including a torque limiter 103c attached to the other end, compression coil springs 103d and 103e, metal retaining retaining rings 103f and 103g, and position restricting retaining rings 103h and 103i. Further, as shown in FIG. 12, D-cut portions 103j and 103k and retaining ring engaging grooves 103l to 103o are formed on the metal rotating shaft 103a by cutting. As shown in FIG. 10, the rotating shaft 103a is rotatably attached to one side surface 101a of the chassis 101 by a bearing member 104, and the position in the axial direction is restricted by position restricting retaining rings 103h and 103i. . Further, the reel engaging portion 103b of the winding member 103 is disposed so as to protrude from the one side surface 101a of the chassis 101 to the inner surface side. As shown in FIGS. 11 and 12, the resin-made reel engaging portion 103b has a D-shaped through hole 103p for inserting the D-cut portion 103j of the rotating shaft 103a and three protruding ribs 103q. is doing.

  As shown in FIG. 10, the torque limiter 103c includes a gear 103r that is rotated by a driving force from the motor 107 (see FIG. 8), a felt 103s that contacts the gear 103r, and a circular shape to which the felt 103s is attached. Plate 103t. Further, as shown in FIGS. 10 and 12, the plate 103t of the torque limiter 103c is formed with a D-shaped through hole 103u for inserting the D-cut portion 103k of the rotating shaft 103a and a recess 103v. Yes. The compression coil spring 103d is disposed between the reel engaging portion 103b and the position restricting retaining ring 103h so as to bias the reel engaging portion 103b toward the reel 102a of the film storage member 102. The compression coil spring 103e is arranged between the recess 103v of the plate 103t and the retaining ring 103f so as to bias the plate 103t in the direction of the gear 103r via the felt 103s.

  Further, as shown in FIG. 8, the thermal head 105 that performs printing is attached to the inside of the one side surface 101a and the other side surface 101b of the chassis 101 so as to be rotatable about a support shaft. The motor 107 attached to the motor bracket 106 has a function as a drive source for driving the gear 103 r of the torque limiter 103 c of the winding member 103 and the paper supply / discharge roller gear 109. Further, the gear 103 r and the paper supply / discharge roller gear 109 of the torque limiter 103 c of the winding member 103 are engaged with the plurality of intermediate gears 110. The plurality of intermediate gears 110 have a function of transmitting the driving force from the motor 107 to the paper supply / discharge roller 108 via the paper supply / discharge roller gear 109.

  Next, the mechanism of power transmission in the winding member 103 of the conventional thermal transfer printer will be described with reference to FIGS. First, as shown in FIG. 10, the plate 103t of the torque limiter 103c is urged in the direction of the gear 103r by the compression coil spring 103e housed in the recess 103v of the plate 103t, so that the driving force of the gear 103r is felt. It is transmitted to the plate 103t via 103s. As a result, the gear 103r and the plate 103t rotate integrally. Next, as shown in FIGS. 10 and 12, the plate 103t of the torque limiter 103c is attached by inserting one D-cut portion 103k of the rotating shaft 103a into the D-shaped through hole 103u of the plate 103t. Therefore, the plate 103t of the torque limiter 103c and the rotating shaft 103a rotate integrally.

As shown in FIGS. 10 and 12, the reel engaging portion 103b is also attached by inserting the other D-cut portion 103j of the rotating shaft 103a into the D-shaped through hole 103p of the reel engaging portion 103b. Therefore, the rotating shaft 103a and the reel engaging portion 103b rotate integrally. As a result, when the driving force is transmitted to the gear 103r of the torque limiter 103c and the torque limiter 103c rotates in the direction of arrow F in FIG. 9, the reel engaging portion 103b similarly rotates in the direction of arrow F in FIG. . In this case, when a load torque greater than a predetermined torque is applied to the reel engaging portion 103b, the felt 103s attached to the plate 103t shown in FIG. 10 slides with respect to the gear 103r. Therefore, even if the gear 103r rotates, the plate 103t Will not rotate. As a result, when a load torque greater than a predetermined torque is applied to the reel engaging portion 103b, power is not transmitted to the rotating shaft 103a, and the rotating shaft 103a does not rotate.
JP 2002-245734 A JP-A-9-86008 JP-A-5-134495 JP 7-276735 A

  In the conventional thermal transfer printer shown in FIGS. 8 to 12, the metal rotary shaft 103 a to which the reel engaging portion 103 b of the winding member 103 and the plate 103 t of the torque limiter 103 c are attached can be rotated on the chassis 101. Therefore, the bearing member 104 provided separately from the chassis 101 and the position restricting retaining rings 103h and 103i for restricting the position of the rotating shaft 103a in the axial direction are required. . As a result, there is a problem that the number of parts increases. Further, in the conventional thermal transfer printer shown in FIGS. 8 to 12, the rotary shaft 103a of the winding member 103 is rotatably supported by only one bearing 104, so that the rotary shaft 103a can be stably rotated. There was also a problem that it was difficult to support. Therefore, it is conceivable to support the rotating shaft 103a with two bearings. However, in this case, in addition to the chassis 101 to which one bearing is attached, the other bearing and a dedicated bracket to which the bearing is attached are newly required, and there is a problem that the number of parts increases accordingly. .

  Further, in the structure disclosed in Patent Document 1, after a metal lead screw (rotary shaft) is rotated in parallel to the surface of the chassis, a bearing is formed on the metal chassis by burring. Further, it is necessary to perform a process of bending the bearing-forming projection formed with the bearing by 90 °. As a result, there is a problem that the processing time is increased to form a bearing that rotatably supports the lead screw (rotating shaft). Further, since the lead screw (rotating shaft) is arranged in parallel to the surface of the chassis, when the rotating shaft of the winding member is attached instead of the lead screw (rotating shaft), the rotating shaft of the winding member Are also arranged parallel to the surface of the chassis. In this case, the reel of the film storage member arranged in the direction perpendicular to the surface of the chassis is engaged with the reel engaging portion attached to the tip of the rotating shaft of the winding member arranged on the surface of the chassis. It is thought that the problem that it becomes difficult to make it occur.

Further, in the structure disclosed in Patent Document 2, since the gear attached to the paper feed roller is rotatably supported by only one bearing provided on the chassis, the paper feed roller to which the gear is attached is provided. There is a problem that it is difficult to stably and rotatably support. Therefore, it is conceivable to support the paper feed roller with two bearings. However, in this case, in addition to the chassis to which one bearing is attached, the other bearing and a dedicated bracket to which the bearing is attached are newly required, and there is a problem that the number of parts increases accordingly.

  In the structure disclosed in Patent Document 3, two bearing members attached to a feed unit (chassis) and two support members (bearings) are provided in order to rotatably support the shaft of the feed roller. Since it needs to be provided, there is a problem that the number of parts increases accordingly.

  Further, in the structure disclosed in Patent Document 4, it is necessary to attach a support shaft to the surface of the chassis in order to rotatably support a reel base (winding member) having a torque limiter mechanism. Therefore, there is a problem that the number of parts increases in order to rotatably support the reel base (winding member). Further, since only one end portion of the support shaft is fixed to the chassis, there is a problem that the rotation of the reel base is likely to be unstable as compared with the case where both ends of the support shaft are fixed.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to stabilize a winding member having a torque limiter without increasing the number of parts and processing time. An image forming apparatus capable of being rotatably supported is provided.

  An image forming apparatus according to a first aspect of the present invention is engaged with a metal chassis to which a printing unit is attached, a metal motor bracket to which a motor as a drive source is attached, and a film storage member in which a film is stored. An engagement portion, a resin main body portion that is engaged with the engagement portion and rotates integrally with the engagement portion, and a torque limiter that is attached to the main body portion, for winding the film of the film storage member In the image forming apparatus including the winding member, one end is attached to the chassis, the coil forming member further includes a coil spring for suppressing the rotation of the winding member in the reverse direction, and the main body portion of the winding member is the first shaft portion. A metal shaft including a second shaft portion, a spring mounting portion having an outer peripheral surface that is rotatably fitted to the inner peripheral surface of the coil spring, and a plate portion that constitutes a torque limiter. Includes a first bearing portion that is integrally formed so as to protrude in a cylindrical shape substantially vertically from the surface of the chassis, and that rotatably supports the first shaft portion of the main body portion of the winding member, The manufactured motor bracket is integrally formed so as to protrude in a cylindrical shape in a substantially vertical direction from the surface of the motor bracket, and is a second bearing that rotatably supports the second shaft portion of the main body portion of the winding member. Part.

In the image forming apparatus according to the first aspect, as described above, the first shaft portion is provided in the resin main body portion of the winding member, and the metal chassis is substantially perpendicular to the surface of the chassis. By integrally forming the first bearing portion that rotatably supports the first shaft portion of the main body portion of the winding member so as to protrude in a cylindrical shape, the winding member including the resin-made main body portion, It can support rotatably by the 1st bearing part integrally provided in the metal chassis. This eliminates the need for the metal shaft and the bearing member as compared to the case where the bearing member attached to the metal chassis rotatably supports the metal shaft to which the main body of the winding member is attached. Therefore, the number of parts can be reduced accordingly. Further, the main body portion of the winding member is provided on the chassis by rotatably supporting the second shaft portion of the main body portion of the winding member by the second bearing portion provided integrally with the motor bracket. Since it can be supported at two locations, the first bearing portion and the second bearing portion provided on the motor bracket, the winding member is more stable than when the winding member is rotatably supported at one location. Can be rotated. A bearing member for rotatably supporting the second shaft portion of the main body portion of the winding member by integrally forming a second bearing portion on a motor bracket to which a motor as a drive source is attached, and Since it is not necessary to separately provide a dedicated bracket for attaching the bearing member, the number of parts does not increase even when the main body of the winding member is supported at two locations. In addition, by forming the first bearing portion so as to protrude in a cylindrical shape from the surface of the chassis in the vertical direction, the winding member is rotatably inserted into the first bearing portion, whereby the winding member The main body portion is arranged in a direction perpendicular to the surface of the chassis. Thereby, the engaging part engaged with the main-body part of a winding member can be easily engaged with the film storage member arrange | positioned in the orthogonal | vertical direction with respect to the surface of a chassis. In this case, since it is not necessary to bend the portion of the chassis provided with the first bearing portion formed in the vertical direction on the surface of the chassis by 90 °, the processing time can be reduced accordingly. Further, by integrally providing the plate portion constituting the torque limiter in the resin main body portion, the number of parts can be reduced as compared with the case where the plate portion is provided separately from the main body portion. Further, by forming the first bearing portion and the second bearing portion integrally with the chassis and the motor bracket by burring, respectively, the surface can be easily integrated with the surface of the metal chassis and the metal motor bracket. A 1st bearing part and a 2nd bearing part can be formed so that it may protrude in a cylinder shape. In addition, a coil spring is provided with one end attached to the chassis to suppress the reverse rotation of the winding member, and an outer periphery that is rotatably fitted to the inner peripheral surface of the coil spring in the main body of the winding member By providing a spring mounting portion having a surface, when the winding member rotates in the reverse direction, the inner diameter of the coil spring is reduced, so that the winding member is caused by the film load. Since the rotation in the reverse direction is suppressed by the frictional resistance between the inner peripheral surface of the coil spring and the outer peripheral surface of the spring mounting portion, it is possible to easily suppress the rotation in the direction opposite to the winding direction of the winding member. it can.

  An image forming apparatus according to a second aspect of the present invention is engaged with a metal chassis to which a printing unit is attached, a metal motor bracket to which a motor as a drive source is attached, and a film storage member in which a film is stored. An engagement portion, a resin main body portion that is engaged with the engagement portion and rotates integrally with the engagement portion, and a torque limiter provided on the main body portion, for winding the film of the film storage member A resin main body portion having a first shaft portion and a second shaft portion, and the metal chassis protrudes from the surface of the chassis in a substantially vertical direction in a cylindrical shape. The metal motor bracket includes a first bearing portion that is integrally formed and rotatably supports the first shaft portion of the main body portion of the winding member. The metal motor bracket is cylindrical in a substantially vertical direction from the surface of the motor bracket. To protrude into Body to be formed, including a second bearing portion for rotatably supporting the second shaft portion of the main body portion of the take-up member.

In the image forming apparatus according to the second aspect, as described above, the first shaft portion is provided in the resin main body portion of the winding member, and the metal chassis is substantially perpendicular to the surface of the chassis. By integrally forming the first bearing portion that rotatably supports the first shaft portion of the main body portion of the winding member so as to protrude in a cylindrical shape, the winding member including the resin-made main body portion, It can support rotatably by the 1st bearing part integrally provided in the metal chassis. This eliminates the need for the metal shaft and the bearing member as compared to the case where the bearing member attached to the metal chassis rotatably supports the metal shaft to which the main body of the winding member is attached. Therefore, the number of parts can be reduced accordingly. Further, the main body portion of the winding member is provided on the chassis by rotatably supporting the second shaft portion of the main body portion of the winding member by the second bearing portion provided integrally with the motor bracket. Since it can be supported at two locations, the first bearing portion and the second bearing portion provided on the motor bracket, the winding member is more stable than when the winding member is rotatably supported at one location. Can be rotated. A bearing member for rotatably supporting the second shaft portion of the main body portion of the winding member by integrally forming a second bearing portion on a motor bracket to which a motor as a drive source is attached, and Since it is not necessary to separately provide a dedicated bracket for attaching the bearing member, the number of parts does not increase even when the main body of the winding member is supported at two locations. In addition, by forming the first bearing portion so as to protrude in a cylindrical shape from the surface of the chassis in the vertical direction, the winding member is rotatably inserted into the first bearing portion, whereby the winding member The main body portion is arranged in a direction perpendicular to the surface of the chassis. Thereby, the engaging part engaged with the main-body part of a winding member can be easily engaged with the film storage member arrange | positioned in the orthogonal | vertical direction with respect to the surface of a chassis. In this case, since it is not necessary to bend the portion of the chassis provided with the first bearing portion formed in the vertical direction on the surface of the chassis by 90 °, the processing time can be reduced accordingly.

  In the image forming apparatus according to the second aspect, preferably, the resin main body portion integrally includes a plate portion constituting a torque limiter. If comprised in this way, a number of parts can be reduced compared with the case where a plate part is provided separately from a main-body part.

  In the image forming apparatus according to the second aspect, preferably, the first bearing portion and the second bearing portion are each integrally formed on the chassis and the motor bracket by burring. If comprised in this way, a 1st bearing part and a 2nd bearing part can be easily formed so that it may protrude from the surface of a metal chassis and a metal motor bracket integrally in a cylindrical shape.

  In the image forming apparatus according to the second aspect described above, preferably, one end is attached to the chassis, and further provided with a coil spring for suppressing the reverse rotation of the winding member. A spring mounting portion having an outer peripheral surface that is rotatably fitted to the inner peripheral surface is included. With this configuration, when the winding member rotates in the reverse direction, the winding spring rotates in the direction opposite to the winding direction due to the film load by reducing the inner diameter of the coil spring. Since this is suppressed by the frictional resistance between the inner peripheral surface of the coil spring and the outer peripheral surface of the spring mounting portion, rotation in the direction opposite to the winding direction of the winding member can be easily suppressed.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing the overall configuration of a thermal transfer printer according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state where a film storage member is removed from the thermal transfer printer according to the embodiment of the present invention shown in FIG. 3 to 7 are views for explaining the detailed structure of the winding member of the thermal transfer printer according to the embodiment of the present invention. The structure of a thermal transfer printer according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, a case where the present invention is applied to a thermal transfer printer which is an example of an image forming apparatus will be described.

  As shown in FIGS. 1, 2, and 7, the thermal transfer printer according to the embodiment of the present invention includes a metal chassis 1, a film storage member 2, a winding member 3, and a clutch spring 4 (see FIG. 7). ), A thermal head 5 for performing printing, a platen roller 6 disposed so as to face the thermal head 5, a platen roller bearing 7 for rotatably supporting the platen roller 6, and a side plate 8 made of resin. , A motor bracket 9, a motor 10, a rubber paper supply / discharge roller 11, a paper supply / discharge roller gear 12, and a plurality of intermediate gears 13. The clutch spring 4 is an example of the “coil spring” in the present invention, and the thermal head 5 is an example of the “printing unit” in the present invention.

  As shown in FIGS. 1 and 2, the chassis 1 has one side surface 1a and the other side surface 1b. Further, the motor bracket 9 described above is attached to one side surface 1 a of the chassis 1. As shown in FIGS. 3 and 6, a spring mounting hole 1 c into which the one end 4 a of the clutch spring 4 is inserted is provided on one side surface 1 a of the chassis 1. As shown in FIG. 2, the other side surface 1 b of the chassis 1 is provided with a storage member insertion hole 1 d for attaching the film storage member 2.

Here, in this embodiment, as shown in FIGS. 3 and 6, the first bearing portion 1 e is integrally formed on one side surface 1 a of the metal chassis 1 by burring. The first bearing portion 1 e is formed so as to protrude in a cylindrical shape from the surface of the one side surface 1 a of the chassis 1 to the inside of the chassis 1 in the vertical direction.

  As shown in FIG. 5, the film storage member 2 includes a reel 2a provided with a recess 2b having three grooves 2c, and a thermal transfer film 2d wound around the outer peripheral surface of the reel 2a.

  Further, as shown in FIG. 4, the winding member 3 includes a resin-made reel engaging portion 3a that engages with the reel 2a of the film storage member 2, and a reel engaging portion that engages with the reel engaging portion 3a. A resin main body 3b that rotates integrally with 3a, a torque limiter 3c, compression coil springs 3d and 3e, a resin retaining cap 3f, and a metal retaining washer 3g are included. The reel engaging portion 3a is an example of the “engaging portion” in the present invention.

  As shown in FIGS. 4 and 7, the resin-made reel engaging portion 3a is integrally formed with three protruding ribs 3h that engage with the groove 2c of the reel 2a and three protruding portions 3i. Has been. As shown in FIGS. 4 and 6, the reel engaging portion 3a includes a spring insertion portion 3j for attaching the compression coil spring 3d. The spring insertion portion 3j is formed with an insertion hole 3k for inserting the insertion portion 3n of the resin main body portion 3b. In addition, the resin main body 3b has three groove portions that engage with the first shaft portion 31, the second shaft portion 3m, the insertion portion 3n, and the three protrusion portions 3i of the reel engaging portion 3a. 3o, plate portion 3p, and torque limiter mounting portion 3q. Further, the first shaft portion 31 is provided with a spring mounting portion 3r having an outer peripheral surface that is rotatably fitted to the inner peripheral surface of the clutch spring 4. The spring mounting portion 3r is an example of the “spring mounting portion” in the present invention. Further, as shown in FIG. 6, the first shaft portion 31 is rotatably supported by a first bearing portion 1 e provided on one side surface 1 a of the chassis 1. As shown in FIG. 4, the second shaft portion 3m is provided with a retaining portion 3t having a function of preventing the retaining washer 3g from falling off. A convex portion 3u is formed on the retaining portion 3t. Further, as shown in FIG. 6, the insertion portion 3n is provided with a cap insertion hole 3s for inserting a resin retaining cap 3f.

  Further, as shown in FIG. 6, the torque limiter 3c includes a gear 3v that is rotated by a driving force from the motor 10 (see FIGS. 1 and 2), a felt 3w that contacts the gear 3v, and the felt 3w. And the plate portion 3p of the main body portion 3b. That is, in this embodiment, the plate part 3p which comprises the torque limiter 3c is integrally formed with the main-body part 3b. Further, the gear 3v and the felt 3w of the torque limiter 3c are attached to the torque limiter attachment portion 3q of the resin main body portion 3b. The compression coil spring 3d is disposed between the reel engaging portion 3a and the main body portion 3b. As a result, the reel engaging portion 3a is movable in the direction of arrow A in FIG. 5 against the urging force of the compression coil spring 3d. Further, the compression coil spring 3e is disposed between the gear 3v of the torque limiter 3c and the retaining washer 3g so as to urge the gear 3v in a direction of pressing the plate 3p of the main body 3b via the felt 3w. Has been. The resin retaining cap 3f is mounted in a cap insertion hole 3s provided in the insertion portion 3n of the resin main body 3b. Further, as shown in FIG. 4, the metal retaining washer 3g engages with a hole 3x through which the retaining portion 3t of the main body 3b can pass and a convex portion 3u provided on the retaining portion 3t. And a recess 3y.

Moreover, the clutch spring 4 has the one end 4a attached to the spring attachment hole 1c provided in the one side surface 1a of the chassis 1, as shown in FIG.4 and FIG.6. Further, a bent portion 4 b is provided at one end 4 a of the clutch spring 4. The bent portion 4b is provided to prevent the one end 4a attached to the spring attachment hole 1c of the chassis 1 from coming off. Further, the clutch spring 4 has a function of suppressing the rotation in the direction opposite to the winding direction of the film 2d of the winding member 3 (the B direction in FIGS. 5 and 7) (the arrow C direction in FIGS. 5 and 7). Have.

  Further, as shown in FIG. 2, the thermal head 5 that performs printing is rotatably supported on the inner surfaces of the one side surface 1a and the other side surface 1b of the chassis 1 around a support shaft 5a. The platen roller 6 is disposed so as to face the thermal head 5. As shown in FIG. 2, the platen roller 6 is rotatably supported by a platen roller bearing 7 attached to one side surface 1 a and the other side surface 1 b of the chassis 1.

  Further, as shown in FIG. 3, the resin side plate 8 is provided with an escape hole 8 a having a larger diameter than the first bearing portion 1 e provided on the one side surface 1 a of the chassis 1. Further, as shown in FIGS. 1 and 2, a plurality of intermediate gears 13 are rotatably attached to the side plate 8.

  Moreover, in this embodiment, as shown in FIG. 3, the 2nd bearing part 9a is integrally formed in the motor bracket 9 by the burring process. The second bearing portion 9a is provided so as to protrude from the surface of the motor bracket 9 in a cylindrical shape to the outside of the motor bracket 9 in the vertical direction. Further, as shown in FIG. 6, the second shaft portion 3m of the main body portion 3b of the winding member 3 is rotatably supported by the second bearing portion 9a.

  As shown in FIGS. 1 and 2, the motor 10 attached to the motor bracket 9 is a drive source for driving the gear 3 v of the torque limiter 3 c of the winding member 3 and the paper supply / discharge roller gear 12. As a function. Further, the gear 3 v of the torque limiter 3 c of the winding member 3 and the paper supply / discharge roller gear 12 are engaged with a plurality of intermediate gears 13. The plurality of intermediate gears 13 have a function of transmitting the driving force from the motor 10 to the paper supply / discharge roller 11 via the paper supply / discharge roller gear 12.

  Next, a method for assembling the winding member 3 of the thermal transfer printer according to the embodiment of the present invention will be described with reference to FIGS. 3, 4 and 6. First, as shown in FIG. 4, in a state where the compression coil spring 3d is inserted into the insertion portion 3n provided in the resin main body portion 3b, the insertion portion 3n of the main body portion 3b is resisted against the urging force of the compression coil spring 3d. Is inserted into the insertion hole 3k of the reel engaging portion 3a. Furthermore, from this state, the resin retaining cap 3f is press-fitted into a cap insertion hole 3s (see FIG. 6) provided in the insertion portion 3n of the main body portion 3b, whereby the reel engaging portion 3a is removed from the main body portion 3b. Prevent falling off. Next, the felt 3w and the gear 3v of the torque limiter 3c are attached to the torque limiter attaching part 3q of the main body part 3b. Further, in this state, the retaining washer 3g is fitted into the retaining portion 3t of the main body portion 3b so that the compression coil spring 3e is disposed between the gear 3v and the retaining washer 3g. At this time, the retaining washer 3g is pressed against the urging force of the compression coil spring 3e. Further, from this state, the retaining washer 3g is rotated 90 ° while pressing the compression coil spring 3e, and then the recess 3y of the retaining washer 3g and the projection 3u of the retaining portion 3t are engaged. Thereby, the retaining washer 3g is attached to the retaining portion 3t of the main body portion 3b. As a result, the winding member 3 having the torque limiter 3c is assembled as shown in FIG.

Next, the printing operation of the thermal head 5 for printing on a sheet will be described. First, a driving force from a motor (not shown) is transmitted to the thermal head 5, and the thermal head 5 is rotated around a support shaft 5a (see FIG. 2). Thereby, the thermal head 5 presses the platen roller 6 through the film 2d and the paper. In this state, the reel 2a of the film storage member 2 around which the film 2d is wound is wound up by the reel engaging portion 3a of the winding member 3 that engages with the reel 2a. At the same time, the sheet is conveyed by a feed roller (not shown), and printing is performed on the sheet.

  Next, the winding operation of the film 2d of the winding member 3 of the thermal transfer printer according to one embodiment of the present invention will be described with reference to FIGS. When the motor 10 is driven to rotate, the gear 3v of the torque limiter 3c rotates in the direction of arrow B in FIGS. 5 and 7 via the plurality of intermediate gears 13. And rotation of the gear 3v is transmitted to the plate part 3p of the main-body part 3b via the felt 3w. As a result, the main body 3b rotates in the direction of arrow B in FIGS. 5 and 7, and the reel engaging portion 3a that engages with the main body 3b also rotates in the direction of arrow B in FIGS. Thereby, the reel 2a of the film storage member 2 engaged with the reel engaging portion 3a rotates in the direction of arrow C in FIG. In this way, the film 2d of the film storage member 2 is wound up. In this case, when a load torque higher than a predetermined torque is applied to the reel engaging portion 3a, the felt 3w attached to the plate portion 3p shown in FIG. 6 slides with respect to the gear 3v, and therefore the main body even if the gear 3v rotates. The plate portion 3p of the portion 3b does not rotate. Thus, when a load torque equal to or greater than a predetermined torque is applied to the reel engaging portion 3a, power is not transmitted to the main body portion 3b, and the main body portion 3b does not rotate.

  When the reel 2a tries to rotate in the direction of arrow D in FIG. 5 due to the load of the film 2d of the film storage member 2, the reel engaging portion 3a that engages with the reel 2a of the film storage member 2 is shown in FIG. And it tries to rotate in the direction of arrow C in FIG. In this case, the inner diameter of the clutch spring 4 attached to the winding member 3 is reduced, and the frictional resistance between the inner peripheral surface of the clutch spring 4 and the outer peripheral surface of the spring mounting portion 3r is increased. However, rotation in the direction opposite to the winding direction (the direction of arrow B in FIGS. 5 and 7) (the direction of arrow C in FIGS. 5 and 7) is suppressed.

  In the present embodiment, as described above, the first shaft portion 31 is provided on the resin main body portion 3b of the winding member 3, and the surface of the one side surface 1a of the chassis 1 is provided on the one side surface 1a of the metal chassis 1. By integrally forming the first bearing portion 1e that rotatably supports the first shaft portion 31 of the main body portion 3b of the winding member 3 so as to protrude in a cylindrical shape substantially vertically from the resin, The winding member 3 including the main body 3b made of metal can be rotatably supported by the first bearing portion 1e provided integrally with the metal chassis 1. This eliminates the need for the metal shaft and the bearing member as compared to the case where the bearing member attached to the metal chassis rotatably supports the metal shaft to which the main body of the winding member is attached. Therefore, the number of parts can be reduced accordingly.

  Further, in the present embodiment, the winding member is supported by the second shaft portion 3m of the main body 3b of the winding member 3 so as to be rotatable by the second bearing portion 9a provided integrally with the motor bracket 9. 3 can be supported at two locations, the first bearing portion 1e provided on the chassis 1 and the second bearing portion 9a provided on the motor bracket 9, so that the winding member 3 is provided at one location. The winding member 3 can be stably rotated as compared with the case where it is supported rotatably.

  In the present embodiment, the second shaft portion 3m of the main body portion 3b of the winding member 3 is formed by integrally forming the second bearing portion 9a on the motor bracket 9 to which the motor 10 as a drive source is attached. Since there is no need to separately provide a bearing member for rotatably supporting and a dedicated bracket for mounting the bearing member, the number of parts increases even when the main body 3b of the winding member 3 is supported at two locations. There is no.

Moreover, in this embodiment, the main body of the winding member 3 is formed in the first bearing portion 1e by forming the first bearing portion 1e so as to protrude in a cylindrical shape from the surface of the one side surface 1a of the chassis 1 in the vertical direction. By inserting the portion 3 b in a rotatable manner, the main body portion 3 b of the winding member 3 is arranged in a direction perpendicular to the surface of the one side surface 1 a of the chassis 1. Thereby, the reel engaging portion 3a engaged with the main body portion 3b of the winding member 3 can be easily applied to the reel 2a of the film storage member 2 arranged in the direction perpendicular to the surface of the one side surface 1a of the chassis 1. Can be engaged. In this case, since it is not necessary to bend the portion of the chassis 1 in which the first bearing portion 1e is formed by 90 °, the processing time can be reduced accordingly.

  Moreover, in this embodiment, by providing the plate part 3p which comprises the torque limiter 3c integrally in the resin-made main-body part 3b, compared with the case where the plate part 3p is provided separately from the main-body part 3b, The number of parts can be reduced.

  In the present embodiment, the first bearing portion 1e and the second bearing portion 9a are formed integrally with the chassis 1 and the motor bracket 9 by burring, respectively, so that the metal chassis 1 and the metal can be easily formed. The 1st bearing part 1e and the 2nd bearing part 9a can be formed so that it may protrude from the surface of the motor bracket 9 made integrally in the shape of a cylinder.

  Further, in the present embodiment, one end 4a is attached to the chassis 1, and a clutch spring 4 is provided for suppressing the rotation of the winding member 3 in the reverse direction (the direction of arrow C in FIGS. 5 and 7). A spring mounting portion 3 r having an outer peripheral surface that is rotatably fitted to the inner peripheral surface of the clutch spring 4 is provided on the main body portion 3 b of the taking member 3. Thereby, when the winding member 3 rotates in the reverse direction (the direction of arrow C in FIGS. 5 and 7), the inner diameter of the clutch spring 4 is reduced. As a result, the winding member 3 tends to rotate in the direction (arrow C direction in FIGS. 5 and 7) opposite to the winding direction (arrow B direction in FIGS. 5 and 7) due to the load of the film 2d. In this case, the winding direction of the winding member 3 (in the direction of arrow B in FIGS. 5 and 7) is easily reversed by the frictional resistance between the inner peripheral surface of the clutch spring 4 and the outer peripheral surface of the spring mounting portion 3r. The rotation in the direction (the direction of arrow C in FIGS. 5 and 7) can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above embodiment, a thermal transfer printer is shown as an example of an image forming apparatus. However, the present invention is not limited to this, and any image forming apparatus including a winding member having a torque limiter can be used. The present invention can also be applied to other image forming apparatuses.

  Moreover, in the said embodiment, although the example which forms a 1st bearing part and a 2nd bearing part in a chassis and a motor bracket by a burring process, respectively was shown, this invention is not limited to this, and it is the 1st bearing part by another processing method. One bearing portion and a second bearing portion may be formed.

1 is a perspective view showing an overall configuration of a thermal transfer printer according to an embodiment of the present invention. It is the perspective view which showed the state which removed the film storage member from the thermal transfer printer by one Embodiment shown in FIG. FIG. 2 is a perspective view of a chassis, a motor bracket, and a winding member of the thermal transfer printer according to the embodiment shown in FIG. 1. It is a disassembled perspective view of the winding member of the thermal transfer printer by one Embodiment shown in FIG. It is a perspective view of the film storage member and winding member of the thermal transfer printer by one Embodiment shown in FIG. It is sectional drawing of the winding member of the thermal transfer printer by one Embodiment shown in FIG. It is a top view of the winding member of the thermal transfer printer by one Embodiment shown in FIG. It is the perspective view which showed the whole structure of the thermal transfer printer by an example of the past. FIG. 9 is a perspective view of a film storage member and a winding member of the thermal transfer printer according to the conventional example shown in FIG. 8. It is sectional drawing of the winding member by an example of the prior art shown in FIG. It is the top view which showed the reel engaging part of the thermal transfer printer by an example of the prior art shown in FIG. It is the perspective view which showed the support shaft of the thermal transfer printer by an example of the prior art shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chassis 1e 1st bearing part 2 Film storage member 2d Film 3 Winding member 3a Reel engaging part (engaging part)
3b Body 3c Torque limiter 3r Spring mounting part (spring mounting part)
3l 1st shaft part 3m 2nd shaft part 3p plate part 4 Clutch spring (coil spring)
4a One end 9 Motor bracket 9a Second bearing portion 10 Motor

Claims (5)

A metal chassis to which a printing unit is attached, a metal motor bracket to which a motor as a drive source is attached, an engagement portion that engages with a film storage member that stores a film, and is engaged with the engagement portion. A resin main body that rotates integrally with the engagement portion, and a winding member that includes a torque limiter provided on the main body and winds the film of the film storage member. In the forming device,
One end is attached to the chassis, further comprising a coil spring for suppressing the reverse rotation of the winding member,
The main body of the winding member constitutes a first shaft portion, a second shaft portion, a spring mounting portion having an outer peripheral surface that is rotatably fitted to an inner peripheral surface of the coil spring, and the torque limiter. Including a plate portion,
The metal chassis is integrally formed so as to protrude in a cylindrical shape substantially vertically from the surface of the chassis, and a first shaft portion of the main body portion of the winding member is rotatably supported. Including one bearing part,
The metal motor bracket is integrally formed so as to protrude in a substantially vertical direction from the surface of the motor bracket, and rotatably supports the second shaft portion of the main body portion of the winding member. An image forming apparatus including a second bearing portion. A metal chassis to which the print unit is attached;
A metal motor bracket to which a motor as a drive source is attached;
An engagement portion that engages with a film storage member in which a film is stored, a resin-made main body portion that engages with the engagement portion and rotates integrally with the engagement portion, and a torque provided in the main body portion A limiter, and a winding member for winding the film of the film storage member,
The resin main body has a first shaft portion and a second shaft portion,
The metal chassis is integrally formed so as to protrude in a cylindrical shape substantially vertically from the surface of the chassis, and a first shaft portion of the main body portion of the winding member is rotatably supported. Including one bearing part,
The metal motor bracket is integrally formed so as to protrude in a substantially vertical direction from the surface of the motor bracket, and rotatably supports the second shaft portion of the main body portion of the winding member. An image forming apparatus including a second bearing portion.   The image forming apparatus according to claim 2, wherein the resin main body portion integrally includes a plate portion constituting the torque limiter.   4. The image forming apparatus according to claim 2, wherein the first bearing portion and the second bearing portion are each integrally formed on the chassis and the motor bracket by burring. 5. One end is attached to the chassis, further comprising a coil spring for suppressing the reverse rotation of the winding member,
5. The image forming apparatus according to claim 2, wherein the main body portion of the winding member includes a spring mounting portion having an outer peripheral surface that is rotatably fitted to an inner peripheral surface of the coil spring.

Images