JP2011037043A - Printing mechanism and thermal printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing mechanism in which paper can be conveyed smoothly when thermal transfer printing is performed on the inner surface of roll paper, the rear end of the paper is prevented from jumping to a thermal head side, and an unnecessary horizontal streak can be prevented from being generated in the paper. <P>SOLUTION: In the printing mechanism 3 which performs thermal transfer printing on the inner surface Sa of paper S fed from a roll paper feeding part 2 and conveyed between a thermal head 31 and a platen 32, a paper guide G for guiding the paper S toward a pressure contact part P is arranged at the upstream side of the pressure contact part P of the thermal head 31 and platen 32 in the printing direction B. A main guide G1 which comes into contact with the central part of the paper S in the width direction is formed in the paper guide G, and the inclination angle of the main guide G1 is set larger than the inclination angle of the other part (sub-guide G2) of the paper guide G in a direction receding from the thermal head body 311. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing mechanism and a thermal printer.

  2. Description of the Related Art Conventionally, there is known a thermal printer that uses the heat of a thermal head to transfer and print sublimation ink or melt ink applied to an ink ribbon onto a sheet. In this type of thermal printer, the thermal head is pressed against the platen roller side against the paper and the ink ribbon superimposed in the thickness direction on the platen roller, and the thermal head is heated while the ink ribbon is in close contact with the paper. Thus, a desired image or the like can be printed on the paper by thermally transferring the ink onto the paper.

  In addition, before performing thermal transfer printing processing, a thermal printer temporarily removes paper (rolled paper) wound in a roll shape by a paper feeding unit by a size corresponding to the screen size and the number of screens to be printed. The paper is sent to the paper discharge unit side from the pressure contact part (thermal transfer printing position) with the platen roller, and the thermal transfer printing process is performed on the paper passing between the thermal head and the platen roller while returning the paper to the paper feeding unit side. It is usually set to. In a printer having such a normal configuration, a thermal head is disposed on the upper side of a sheet passage (pass line), and a platen roller is disposed on the lower side.

  By the way, if the paper wound in a roll shape at the paper feed unit has a curl, and the print processing is performed on the inner winding surface of the paper to be the printing surface, the thermal transfer printing position during the thermal transfer printing process There is a risk that the rear end portion of the sheet conveyed toward the top will spring up and come into contact with the thermal head on the upper side due to the curl. If the print processing is performed on the outer winding surface of the paper, the trailing edge of the paper jumps in the direction away from the thermal head during the print processing. The surface of the sheet held on the sheet becomes a print screen, and one roll of sheet is discarded to prevent quality deterioration due to dirt or the like. In order to avoid such inefficient use of the paper, there is a request that the print processing should be performed on the inner winding surface of the paper.

  However, when printing is performed on the inner winding surface of the paper, if the rear end portion of the paper that has jumped to the thermal head contacts the thermal head, the vibration is generated through the heating element of the thermal head and the heating element. This is transmitted to the ribbon or the paper, which may cause a print defect such as a horizontal stripe on the paper. Such a problem may also occur when the paper transport direction during the thermal transfer printing process coincides with the direction from the paper feed unit side toward the pressure contact portion between the thermal head and the platen roller.

  Therefore, using a part of the thermal head or using a member separate from the thermal head, the paper is made to follow the pass line while contacting the entire area in the width direction of the paper conveyed in the printing direction. Thus, a mode in which a paper guide portion that guides in the printing direction is also conceivable (refer to Patent Document 1 for a mode in which the guide portion is configured using a part of the thermal head).

JP 2007-76362 A

  However, when such a paper guide portion is adopted, the paper guide portion contacts the entire area in the width direction of the paper conveyed in the printing direction, so that the frictional resistance between the paper and the guide member increases, It is thought that the trouble of causing trouble in smooth conveyance occurs. In addition, as a result of the paper not being smoothly conveyed, the posture of the paper at the time of print processing becomes unstable, which is considered to be a cause of horizontal streaks on the paper.

  The present invention has been made paying attention to such problems, the main purpose of which can smoothly carry the paper when performing the thermal transfer printing process on the inner winding surface of the paper, A printing mechanism capable of preventing the rear end of the paper from suddenly jumping to the thermal head side and coming into contact with the thermal head, and performing high-quality thermal transfer printing processing without causing unnecessary lines on the paper, and An object is to provide a thermal printer having a printing mechanism.

  In other words, the present invention includes a thermal head and a platen that can sandwich the paper and the ink ribbon between the thermal heads, and is supplied from a paper feeding unit that can store paper wound in a roll shape with the printing surface facing inward. The paper is transported between the thermal head and the platen, and the ink ribbon is applied to the ink ribbon by the heating element formed on the thermal head in a state where the ink ribbon is superimposed on the inner winding surface (inward surface) that becomes the printing surface. This is a printing mechanism of a thermal printer that performs thermal transfer printing processing on the inner winding surface of a sheet by applying heat. The printing mechanism according to the present invention is more in line with the printing direction, which is the paper conveyance direction during the thermal transfer printing process, than the pressure-contact portion between the thermal head having the thermal head body with the heat generating elements arranged at predetermined locations and the platen. A paper guide unit is provided on the upstream side for guiding the paper conveyed toward the press contact portion between the thermal head and the platen along the print direction, and a part of the paper guide unit along the paper width direction is further provided. The main guide part which can contact only is formed, and the inclination angle of the main guide part is set larger in the direction away from the thermal head body than the inclination angle of the other parts.

  In such a case, the inclination angle of the main guide portion that can contact only a part of the paper guide portion along the paper width direction is set larger in the direction away from the thermal head body than the other portions. Thus, the paper is conveyed in the print direction in a state where only the main guide portion is in contact with the paper via the ink ribbon, or in a state where the main guide portion is in contact with the paper via the ink ribbon in preference to other portions. Compared with the mode in which the paper is guided while the entire width direction of the paper guide portion is in contact with the paper via the ink ribbon, the friction resistance between the paper guide portion and the paper or the ink ribbon is reduced by reducing the contact area. The sheet can be conveyed in the printing direction in a stable state.

  Further, when performing thermal transfer printing on the inner winding surface of the paper wound in a roll shape, the rear end of the paper conveyed in the printing direction may jump up to the thermal head main body side. Since the mechanism guides the sheet to the pressure contact portion between the thermal head and the platen while bringing the sheet into contact with the main guide portion of the sheet guide portion via the ink ribbon, the trailing edge of the sheet can be prevented from jumping up. As a result, it is possible to prevent / suppress printing defects such as lateral streaks caused by vibrations when the paper springs up and contacts the thermal head main body.

  Further, the printing mechanism according to the present invention protrudes in a predetermined area in the main guide portion of the paper guide portion on the upstream side in the printing direction over other regions, and has priority in the printing direction over other regions. Therefore, a priority guide portion that can come into contact with the conveyed paper can be formed. In this case, a guide region for guiding the paper toward the press-contact portion between the thermal head and the platen along the print direction can be secured long by the protrusion amount of the protrusion, and more stable paper transport can be realized. Furthermore, since the priority guide part is formed only in a predetermined area in the main guide part, the contact area between the paper and the ink ribbon and the paper guide part at the start point of the guide area along the print direction can be minimized. The paper can be guided in a stable posture.

  In the printing mechanism of the present invention, the paper guide portion can be configured by using a dedicated member, but the thermal head is provided with an IC circuit for controlling the heat generation of the heating element and an IC cover for protecting the IC circuit. In the case of this embodiment, a paper guide portion can be formed on this IC cover. Thereby, the common use of members and the simplification of the structure can be achieved.

  In addition, in order to be able to guide the paper in a well-balanced state when transporting the paper toward the press-contact part along the print direction, the main guide part is positioned at the center in the width direction of the paper guide part. It is preferable to form the portion.

  In addition, a thermal printer according to the present invention includes a paper feed unit that can store paper wound in a roll shape, a paper discharge unit that discharges paper as cut paper cut to a predetermined size, a paper feed unit, and paper discharge And the above-described printing mechanism disposed between the printing unit and the printing unit. Such a thermal printer exhibits various effects obtained by the above-described printing mechanism and is excellent in practicality.

  According to the present invention, it is possible to smoothly carry the paper when performing the thermal transfer printing process on the inner winding surface of the paper wound in a roll shape, and the rear end of the paper is unexpectedly moved to the thermal head side. A printing mechanism capable of performing high-quality thermal transfer printing processing that prevents a large amount of paper from jumping and coming into contact with the thermal head and causing unnecessary streaks on the paper, and a thermal printer including the printing mechanism are provided. thing

1 is a schematic diagram of an internal configuration of a thermal printer including a printing mechanism according to an embodiment of the present invention. FIG. 2 is an external view of a thermal printer according to the embodiment. The principal part enlarged view of FIG. The side view of the IC cover in the embodiment. The X direction arrow line view in FIG. FIG. 2 is an overall view of an IC cover in the same embodiment. FIG. 5 is an end view taken along line xx. FIG. 6 is an end view taken along line yy in FIG. 5. Action explanatory drawing. Action explanatory drawing.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 3 (FIG. 3 is an enlarged view of a main part of FIG. 1 and an ink ribbon 33 to be described later is omitted), the thermal printer 1 according to the present embodiment is applied to a sheet S. The sublimation printer 1 performs a sublimation print (see FIG. 3) process. As shown in FIG. 1, the sublimation printer 1 includes a paper feed unit 2, a printing mechanism 3 that performs sublimation print processing on the surface Sa of the paper S supplied from the paper feed unit 2, and a paper discharge unit 4. (Specifically, the paper discharge port 41 and the paper discharge tray 42 shown in FIG. 2) and the paper S along the paper passage path (pass line) formed between the paper feed unit 2 and the paper discharge unit 4. And a sheet conveying mechanism 5 for conveying the sheet. The sublimation printer 1 includes at least a paper feed unit 2, a printing mechanism 3, and a paper transport mechanism 5 in a common casing C, and a paper discharge port 41 and a paper discharge tray 42 that constitute the paper discharge unit 4. Is exposed to the outside of the housing C.

  The paper feed unit 2 can accommodate the paper S wound in a roll shape with the printing surface facing inward. In the following description, an inner surface serving as a printing surface is referred to as an inner winding surface (inward surface) Sa. The paper discharge unit 4 discharges the paper S, which has been subjected to a desired print process by the printing mechanism 3, as a cut paper cut to a predetermined size from the paper discharge port 41 to the outside of the housing C, and onto the paper discharge tray 42. It can be placed in a stacked state.

  The paper transport mechanism 5 that transports the paper S between the paper feed unit 2 and the paper discharge unit 4 has a paper feed side feed roller arranged in order from the paper feed unit 2 side toward the paper discharge unit 4 side. 51 and a first pinch roller 52, a feed roller 53 and a second pinch roller 54, and a paper discharge side feed roller 55. A pair of the paper feed side feed roller 51 and the first pinch roller 52 and a pair of the feed roller 53 and the second pinch roller 54 are arranged on the paper feed unit 2 side with respect to the printing mechanism 3, and the paper discharge side feed roller 55. Is disposed closer to the paper discharge unit 4 than the printing mechanism 3.

  The feed roller 53 is a first transport direction a that can transport the paper S in the feed-out direction A that feeds the paper S toward the printing mechanism 3, and a second that can be transported in the print direction B that can be printed on the paper S by the printing mechanism 3. The forward and reverse rotation is possible in the transport direction b. The “feeding direction A” described above coincides with the direction from the paper feed unit 2 toward the paper discharge unit 4, and the “print direction B” coincides with the direction from the paper discharge unit 4 toward the paper feed unit 2. In addition, the paper feed side feed roller 51 and the paper discharge side feed roller 55 can be rotated forward and backward as appropriate in correspondence with the feed roller 53, and each pinch roller (the first pinch roller 52 and the second pinch roller 54) can be rotated. In the state where the paper feed side feed roller 51 and the feed roller 53 are in pressure contact with each other via the paper S, the rollers (the feed side feed roller 51 and the feed roller 53) are driven to rotate. Further, in the present embodiment, a paper discharge side cutter unit 57 that cuts the paper S that has undergone the thermal transfer printing process at least at each print screen boundary is disposed between, for example, the paper discharge side feed roller 55 and the paper discharge unit 4. is doing.

  As shown in FIGS. 1 and 3, the printing mechanism 3 includes a thermal head 31, a platen roller 32 disposed at a position facing the thermal head 31, an ink ribbon 33, and the ink ribbon 33 with the thermal head 31. An ink ribbon transport mechanism 34 that transports between the platen roller 32, a print control unit (not shown) that controls at least the operation of the thermal head 31, and a press-contact portion between the thermal head 31 and the platen roller 32, that is, a thermal transfer print position. A peeling portion 35 for peeling the paper S and the ink ribbon 33 in contact with each other beyond P (see FIG. 3 which is an enlarged view of the main part of FIG. 1 and omits the paper S and the ink ribbon 33). It is provided.

  The thermal head 31 prints on the paper S by causing the heat generating elements to generate heat. As shown in FIG. 3, the thermal head 31 includes a thermal head main body 311 provided with a heat generating element at a predetermined position, and an IC circuit 312 (hereinafter referred to as “the heat head element 311”) that is mounted on the thermal head main body 311 and controls the heat generation of the heat generating element. IC 312 ”) and an IC cover 313 for protecting the IC 312.

  In the present embodiment, for example, a direction (width) orthogonal to the transport direction of the paper S, for example, on the downstream side (paper feed unit 2 side) along the print direction (the arrow B direction in FIGS. 1 and 3) of the thermal head main body 311. Heating elements arranged in a line in the direction) are provided. Further, the IC 312 is disposed at a position close to the heat generating element. In this embodiment, the print direction of the thermal head main body 311 is lower than the pressure contact portion (thermal transfer print position P) with the platen roller 32 on the downward surface 311u. Is attached to a portion close to the upstream side (the discharge unit 4 side) along the line so that it cannot be dropped off. In FIG. 3, the IC 312 is shown with a predetermined pattern. The thermal head 31 in which the IC 312 is mounted on the thermal head main body 311 in a posture positioned below the downward surface 311u of the thermal head main body 311 may be used.

  The IC cover 313 is disposed on the downstream side 311u of the thermal head body 311 on the downstream side of the thermal transfer print position P in the print direction (discharge) in order to prevent the paper S, the ink ribbon 33, etc. from contacting the IC 312. It covers the area from the portion close to the paper portion 4 side) to the upstream end portion or the vicinity of the end portion along the print direction. In this embodiment, the IC cover 313 is shown in FIGS. 3 to 8 (FIG. 5 is a view taken in the direction of the arrow X in FIG. 4, FIGS. 7 and 8 are end views taken along line xx in FIG. As shown in the line end view), a base portion B that is attached using a fixing tool such as a screw while being in contact with the downward surface 311u of the thermal head body 311; 1 and a downward projecting portion T having a substantially upward U-shape in a side view and continuously formed at an upstream end (in the direction of arrow B in FIG. It is constituted by a sheet guide portion G formed continuously at the downstream end (sheet feeding portion 2 side) along the printing direction. The IC cover 313 is formed, for example, by bending and cutting a single metal plate, and has a width that is the same as or slightly smaller than the width of the thermal head body 311.

  The base portion B has a shape capable of being in surface contact with the downward surface 311u of the thermal head main body 311 and is formed by penetrating through holes B1 and B2 for inserting a fixing tool in a predetermined portion in the thickness direction (see FIG. 5 and FIG. 6).

  The sheet guide portion G includes a main guide portion G1 formed in the central region in the width direction and a sub guide portion G2 formed in a position sandwiching the main guide portion G1, that is, both side regions in the width direction. The end portion and the distal end portion of the base portion B are connected by the main guide connection portion G3, and the proximal end portion of the sub guide portion G2 and the distal end portion of the base portion B are connected by the sub guide connection portion G4. . Note that the front end and the base end of each part (base part B, main guide part G1, sub guide part G2) are downstream ends (feeding part 2 side) along the print direction, respectively, along the print direction. It means the end on the upstream side (sheet discharge unit 4 side).

  The main guide portion G1 and the sub guide portion G2 each have a smooth surface that forms a predetermined angle with respect to the base portion B, and the height positions of the front end portion of the main guide portion G1 and the front end portion of the sub guide portion G2 are the same or different. They are substantially the same, and both are set at a position slightly lower than the base portion B. Then, by setting the base end portion of the main guide portion G1 to a position lower than the base end portion of the sub guide portion G2, the inclination angle of the main guide portion G1 with respect to the base portion B is set to the sub guide portion G2 with respect to the base portion B. It is larger than the inclination angle. If the shapes of the main guide part G1 and the sub guide part G2 are described in relation to the connection parts G3 and G4, respectively, the main guide part G1 and the sub guide part G2 are respectively connected to the main guide connection part G3 and the sub guide connection. A V-shape formed by the main guide portion G1 and the main guide connection portion G3 is formed into a V shape formed by the sub guide portion G2 and the sub guide connection portion G4. Compared to the character shape, it can be understood that the shape is set to a deep and acute V shape.

  Further, the sheet guide portion G forms a protruding portion G5 that protrudes downward from other regions in a predetermined region in the width direction at the base end portion of the main guide portion G1. The protruding portion G5 is formed integrally with the main guide portion G1, and the inclination angle thereof is set to be the same or substantially the same as the inclination angle of the main guide portion G1 with respect to the base portion B. In the present embodiment, a pair of left and right protrusions G5 are formed in a region sandwiching the central portion in the width direction at the base end portion of the main guide portion G1. Specifically, as shown in FIG. 5, a pair of left and right cutouts GS is formed in a region sandwiching the central portion in the width direction of the main guide connection portion G3, and the cutouts of the base end portions of the main guide portion G1 are formed. The projecting portion G5 is formed by extending the portion facing the portion GS at the same angle as the main guide portion G1.

  Then, when the IC cover 313 is integrally attached to the thermal head main body 311 using a fixture or the like with the base portion B applied to the downward surface 311u of the thermal head main body 311 from below, as shown in FIG. The main guide portion G1 has a posture that is largely inclined in the direction away from the downward surface 311u of the thermal head main body 311 than the sub guide portion G2, and the protruding portion G5 of the main guide portion G1 protrudes obliquely downward from the other portions. It will be in the state. Further, the front end portion of the IC cover 313, that is, the front end portion of the main guide portion G1 and the front end portion of the sub guide portion G2, are closer to the print direction than the press contact portion (thermal transfer print position P) between the thermal head 31 and the platen roller 32. Further, it is disposed on the upstream side (the paper discharge unit 4 side) and at a position where it cannot interfere with the platen roller 32.

  In the present embodiment, such a thermal head 31 is set so as to be movable between a position where the sheet S can be sandwiched with the platen roller 32 and a position where the sheet S cannot be sandwiched by a head drive motor (not shown). Yes.

  The platen roller 32 can sandwich the paper S with the thermal head 31 and has a function of sequentially transporting the paper S while rotating. Accordingly, the platen roller 32 bears a part of the function of the paper transport mechanism 5. The platen roller 32 can rotate in the forward and reverse directions in synchronization with the feed roller 53.

  The ink ribbon 33 is obtained by applying, for example, yellow, magenta, and cyan inks to a long base film. The yellow, magenta, and cyan inks applied to the base film are formed using a dye that sublimes by heat.

  The ink ribbon transport mechanism 34 includes a supply-side ribbon core 341 around which an unused ink ribbon 33 (in which a base film is coated with ink) is wound, and a used ink ribbon 33 (part of ink from the base film or A ribbon-side ribbon core 342 that winds up, a supply-side ribbon guide 343 that guides the ink ribbon 33 unwound from the supply-side ribbon core 341 to the thermal head 31 side, and after passing through the thermal head 31 A take-up ribbon guide 344 for guiding the ink ribbon 33 peeled from the paper S to the take-up ribbon core 342 side is provided. The supply-side ribbon core 341 and the supply-side ribbon guide 343 are arranged on the paper discharge unit 4 side with respect to the thermal head 31, and the take-up side ribbon core 342 and the take-up side ribbon guide 344 are arranged on the paper supply unit 2 side with respect to the thermal head 31. Is done. Therefore, the ink ribbon 33 wound around the supply-side ribbon core 341 is unwound to the thermal head 31 side by the supply-side ribbon guide 343 and the take-up side ribbon guide 344, and is subjected to the sublimation printing process, and then the take-up side. The ribbon core 342 is sequentially wound up. In this embodiment, the ink ribbon 33 and the ink ribbon transport mechanism 34 are unitized and configured to be detachable from the thermal head 31 and the platen roller 32.

  The peeling unit 35 is disposed closer to the paper feed unit 2 than the thermal head 31, and has a peeling unit main body 351 that presses the ink ribbon 33 that is in close contact with each other after the thermal transfer process from the ink ribbon 33 side, and a peeling unit main body 351. And a peeling backup member 352 that backs up the paper S and the ink ribbon 33 from the paper S side. In the present embodiment, the peeling unit main body 351 is configured using, for example, a roller, and is in a position where it does not interfere with the thermal head 31, and the thermal head 31 and the platen roller 32 are mutually connected via the paper S and the ink ribbon 33. The pressure contact portion, that is, the thermal transfer printing position P is arranged as close as possible to the pressure contact portion. As such a peeling backup member 352, the platen roller 32 is used in the present embodiment. Specifically, a portion of the rotating platen roller 32 that is closer to the paper feed unit 2 than the thermal transfer printing position P is caused to function as the peeling backup member 352.

  Further, in the present embodiment, from the ink ribbon 33 side, the ink ribbon 33 and the paper S can be overlapped on the upstream side (the discharge unit 4 side) along the printing direction from the thermal transfer printing position P. A guide roller 36 that can press the ink ribbon 33 and the paper S toward the paper S is disposed. The arrangement position of the guide roller 36 coincides with or substantially coincides with the joining point of the pass line of the ink ribbon 33 and the pass line of the paper S (see FIG. 1).

  Next, the operation and action of the thermal printer 1 according to the present embodiment, in particular, the operation and action of the printing mechanism 3 will be described with reference to FIG. 1, FIG. 3, FIG. 9, FIG. 3, 9, and 10 are schematic diagrams for chronologically explaining the operation of the paper guide portion G during the thermal transfer printing process. In FIGS. 9 and 10, the ink ribbon is the same as FIG. 3. 33 is omitted.

  First, the paper S wound in a roll shape by the paper feeding unit 2 is sequentially passed between the paper feeding side feed roller 51 and the first pinch roller 52 and between the feed roller 53 and the second pinch roller 54. To the printing mechanism 3. At this time, the paper transport mechanism 5 rotates the feed roller 53 in the first transport direction a to transport the paper S in the feed-out direction (the direction of arrow A in FIGS. 1 and 3). In this embodiment, when the feed roller 53 is rotated in the first transport direction a to transport the paper S in the feed-out direction (the arrow A direction in FIGS. 1 and 3), the thermal head 31 of the printing mechanism 3 is used. Is kept in a position where the sheet S cannot be sandwiched between the platen roller 32 and the sheet S is smoothly conveyed. Then, the sheet S is passed between the thermal head 31 and the platen roller 32 as much as the print processing is performed, and is sent to the paper discharge unit 4 side, and is included in the print setting area (print screen) on the inner winding surface Sa of the sheet S. An end portion on the paper feed unit 2 side (this end portion is not cut at that time, and is a portion continuous with the paper S wound in a roll shape in the paper feed unit 2). When the sheet passes or passes, the thermal head 31 of the printing mechanism 3 is moved to a position where the sheet S can be sandwiched between the platen roller 32 and the feed roller 53 is rotated in the second transport direction b. The paper S is conveyed in the printing direction (the direction of arrow B in FIGS. 1 and 3), and the thermal transfer printing process is performed on the paper S passing the thermal transfer printing position P.

  When the thermal printer 1 according to the present embodiment performs thermal transfer printing on the paper S, the thermal printer 1 passes the paper S before passing through the thermal transfer print position P while guiding the paper S to the paper guide portion G formed on the IC cover 313. It is conveyed along the line to the thermal transfer printing position P (see FIGS. 9 and 10). In the thermal printer 1 according to the present embodiment, the main guide portion G1 of the paper guide portion G is greatly inclined in the direction away from the thermal head 31 than the sub guide portion G2, so The portion is brought into contact with the main guide portion G1 via the ink ribbon 33, and both side portions in the width direction of the paper S are conveyed in a posture that does not contact the sub-guide portion G2 or a posture that does not substantially contact. In this manner, the widthwise center portion of the paper S is brought into contact with the main guide portion G1 via the ink ribbon 33, while the widthwise both side portions of the paper S are not brought into contact with or substantially in contact with the paper S guide. As a result, the contact area between the paper S and the ink ribbon 33 and the paper guide part G during the printing process is reduced as compared with the aspect in which the entire area in the width direction of the paper S and the ink ribbon 33 is in contact with the paper guide part G. In addition, the frictional resistance between the paper S and the ink ribbon 33 and the paper guide portion G can be reduced, and the paper S is conveyed in a stable posture in the printing direction (the direction of arrow B in FIGS. 9 and 10). Is possible.

  In particular, the thermal printer 1 according to the present embodiment performs a printing process on the inner winding surface Sa of the paper S, and the rear end Se along the printing direction of the paper S may jump to the thermal head 31 side due to the curl. However, in the present embodiment, the rear end Se of the sheet S is brought into contact with the main guide portion G1 which is inclined more in the direction away from the thermal head 31 than the sub guide portion G2. As shown in FIG. 10, it is possible to prevent the trailing edge Se of the paper S from greatly jumping to the upper thermal head 31 side. As a result, when the trailing edge Se of the paper S greatly jumps to the thermal head 31 side and comes into contact with the thermal head 31, the vibration is transmitted to the heating element, or the platen roller 32 is passed through the ink ribbon 33 and the paper S. Therefore, it is possible to suppress / avoid printing defects caused by transmitting to the printer.

  Furthermore, the thermal printer 1 according to the present embodiment is provided with a protruding portion G5 that extends to the main guide portion G1 on the upstream side (in the illustrated example, obliquely downward) along the printing direction with respect to the other portions, and this protruding portion G5. Is preferentially brought into contact with the rear end Se of the paper S via the ink ribbon 33, so that it is possible to prevent the rear end Se of the paper S from greatly jumping toward the thermal head 31 immediately before reaching the main guide portion G1. In addition, a longer guide area for guiding the paper S by the paper guide portion G can be secured, and the posture of the paper S during the printing process can be made more stable. That is, the protruding portion G5 plays a role as a priority guide portion in the present invention. The protruding end portion (lower end portion in the illustrated example) of the protruding portion G5 serves as a sheet guide start position when the sheet S is conveyed in the printing direction (the arrow B direction shown in FIGS. 9 and 10). Compared with an aspect in which the portion G5 is not provided, the paper guide start position can be set on the upstream side in the printing direction, and the paper S can be started to be guided at an earlier stage. Further, by forming the protruding portion G5 only on a part of the main guide portion G1, the contact area with the ink ribbon 33 and the paper S is further reduced, and the paper with the ink ribbon 33 and the paper S at the start of the guide is reduced. The frictional resistance with the guide part G can be reduced as much as possible.

  Then, the printing mechanism 3 prints (forms) a color image on each print screen on the inner winding surface Sa of the paper S by sublimating yellow, magenta, and cyan inks by the heat of the thermal head 31. At this time, it is possible to perform gradation printing in which the print density level is changed by adjusting the temperature of the thermal head 31, and print a high-quality color image on each print screen on the inner winding surface Sa of the paper S. It is possible. The temperature control and operation of the thermal head 31 are controlled by the print controller.

  When the ink ribbon 33 subjected to the thermal transfer process is attached to the paper S and is in close contact with the paper S, when the ink ribbon 33 passes through the gap formed between the peeling portion main body 351 and the peeling backup member 352, the peeling portion main body 351 is moved to the ink ribbon. The ink ribbon 33 and the paper S are pressed from the 33 side, and the separation backup member 352 backs up the ink ribbon 33 and the paper S from the paper S side, so that the paper S and the ink ribbon 33 are in a stable state, and the peeling portion main body 351 is stable. The ink ribbon 33 can be appropriately peeled from the paper S.

  After the thermal transfer printing process by the printing mechanism 3 is finished, the paper transport mechanism 5 rotates the feed roller 53 in the first transport direction a to transport the paper S in the feed-out direction (the direction of arrow A in FIGS. 1 and 3). Then, the paper is passed through the paper discharge side feed roller 55 and sequentially conveyed to the paper discharge unit 4 side. The thermal printer 1 according to the present embodiment discharges the sheet S from the sheet discharge port 41 of the sheet discharge unit 4 to the outside of the housing C in a state where the sheet S is cut for each print screen by the sheet discharge side cutter unit 57. It is set so that S can be held in a state of being stacked on the paper discharge tray 42.

  As described above, in the printing mechanism 3 according to this embodiment, the inclination angle of the main guide portion G1 that can contact only the central portion in the width direction of the paper S in the paper guide portion G is set to be larger than that of the sub guide portion G2. Therefore, the main guide part G1 is in contact with the sheet S via the ink ribbon 33 or the main guide part G1 has priority over other parts (sub-guide part G2). In this state, the paper S is conveyed in the printing direction while being in contact with the paper S via the ink ribbon 33, and the paper is guided while the entire width direction of the paper guide portion G is in contact with the paper S via the ink ribbon 33. Compared with the mode of guiding S, the contact area can be reduced, the frictional resistance between the paper guide portion G and the paper S or the ink ribbon 33 can be reduced, and the paper S can be reduced. It can be conveyed to the print direction in the state. In particular, in the present embodiment, since the main guide portion G1 is formed at the central portion in the width direction of the paper guide portion G, the paper S can be transported in a good balance state.

  Further, in the thermal printer 1 according to the present embodiment in which the thermal transfer printing process is performed on the inner winding surface (inward surface) Sa of the paper S wound in a roll shape, the paper guide portion G has a steeper slope than the sub guide portion G2. Since the main guide portion G1 set to the above is guided to the pressure contact portion (thermal transfer printing position P) between the thermal head 31 and the platen 32 while the rear end Se of the paper S is brought into contact with the main guide portion G1 via the ink ribbon 33, the winding It is possible to effectively prevent the paper S from jumping up due to wrinkles, and to prevent / suppress printing defects such as horizontal stripes caused by vibration generated when the trailing edge Se of the paper S jumps up and contacts the thermal head main body 311. Can do.

  In particular, the printing mechanism 3 according to the present embodiment protrudes in a predetermined area in the main guide part G1 in the paper guide part G to the upstream side in the print direction from other areas in the main guide part G1, Since the protruding portion G5 that can contact the rear end Se of the sheet S conveyed in the print direction with priority over the area is formed, the sheet S is moved along the print direction with the thermal head 31 and the platen roller 32. The guide area for guiding toward the pressure contact portion (thermal transfer print position P) can be secured longer by the protrusion amount of the protrusion G5, and more stable conveyance of the paper S can be realized. Further, in the present embodiment, the pair of left and right protrusions G5 are formed in a region sandwiching the central portion in the width direction of the main guide portion G1, so that the paper S and the ink ribbon 33 and the paper guide portion G at the starting point of the guide region are formed. The sheet S can be guided in a stable posture.

  Further, the printing mechanism 3 according to the present embodiment uses the IC cover 313 provided in order to avoid the contact of the paper S and the ink ribbon 33 with the IC 312, and integrally forms the paper guide portion G in a part thereof. Therefore, it is possible to achieve commonality of members and simplification of the structure as compared with an aspect in which the sheet guide portion G is configured using a separate dedicated member.

  In addition, this invention is not limited to embodiment mentioned above. For example, the main guide portions may be formed only on both side portions in the width direction of the paper guide portion, or a plurality of main guide portions may be formed at predetermined pitches or intermittently along the width direction of the paper guide portion.

  In the above-described embodiment, an example in which the protrusion formed integrally with the main guide portion is applied as the priority guide portion is exemplified. However, the priority guide portion configured using a member separate from the main guide portion is used as the main guide portion. You may attach to a part integrally. Furthermore, in the above-described embodiment, the priority guide portion is illustrated as a pair formed on the left and right sides at a position sandwiching the center portion in the width direction of the main guide portion. However, the priority guide portion is formed in the center portion in the width direction of the main guide portion. It may be a mode in which only a predetermined pitch is formed or intermittently formed only on both side portions in the width direction of the main guide portion or along the width direction of the guide portion.

  Further, the paper guide portion may be configured using a member separate from the IC cover. Furthermore, the paper guide unit may be configured using a member separate from the thermal head and the platen.

  In addition, a plate-like platen (plastic template) can be applied as a platen disposed at a position facing the thermal head.

  Further, it may be a thermal printer provided with a plurality of printing mechanisms shown in the above-described embodiments. Further, in addition to a thermal printer that sublimates ink, a printing mechanism that exhibits the above-described structure and effects may be applied to various thermal printers having an ink ribbon, such as a type that melts ink. It may be a printing mechanism that performs thermal transfer printing processing on the outward surface of the paper (the surface that faces outward in the state of being wound in a roll).

  In addition, the printing direction, which is the paper conveyance direction during the thermal transfer printing process, may coincide with the direction from the paper feeding unit side toward the pressure contact portion between the thermal head and the platen. In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Thermal printer, sublimation type printer 2 ... Paper feed part 3 ... Printing mechanism 31 ... Thermal head 311 ... Thermal head main body 312 ... IC circuit 313 ... IC cover 32 ... Platen (platen roller)
33 ... Ink ribbon G ... Paper guide part G1 ... Main guide part G5 ... Priority guide part (protruding part)
P ... Press-contact part (thermal transfer print position)
S ... paper Sa ... inner winding surface (inward surface)

Claims (5)

A paper having a thermal head having a thermal head body on which a heating element is formed, and a platen capable of sandwiching paper and an ink ribbon between the thermal head and wound in a roll shape with the printing surface facing inward In the state where the ink ribbon is superimposed on the inner winding surface serving as the printing surface, the heating element supplies the sheet fed from the sheet feeding unit capable of containing the ink and conveyed between the thermal head and the platen. A printing mechanism that performs thermal transfer printing on the inner winding surface of paper by applying heat to the ink ribbon,
Arranged on the upstream side in the printing direction, which is the paper conveyance direction during the thermal transfer printing process, than the pressure contact portion between the thermal head and the platen, the paper conveyed along the printing direction is directed toward the pressure contact portion. It has a paper guide section to guide,
A main guide part that can contact only a part along the paper width direction is provided on the paper guide part, and the inclination angle of the main guide part is greater than the inclination angle of other parts of the paper guide part. The printing mechanism is characterized in that it is set large in the direction away from the printing mechanism. In the paper guide portion, a predetermined region in the main guide portion protrudes upstream from the other region along the print direction, and the paper is conveyed along the print direction in preference to the other region. The printing mechanism according to claim 1, wherein a priority guide portion capable of contacting is formed. The thermal head has an IC circuit that controls the heat generation of the heating element and an IC cover that protects the IC circuit.
The printing mechanism according to claim 1, wherein the paper guide portion is formed on the IC cover. The printing mechanism according to claim 1, wherein the main guide portion is formed at a central portion in the width direction of the paper guide portion. A paper feed unit that can store paper wound in a roll shape with the printing surface facing inward, a paper discharge unit that discharges paper as cut paper cut to a predetermined size, the paper supply unit, and the paper discharge unit A thermal printer comprising the printing mechanism according to any one of claims 1 to 4 disposed between the two.

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