WO2010073740A1

WO2010073740A1 - Thermal printer

Info

Publication number: WO2010073740A1
Application number: PCT/JP2009/050675
Authority: WO
Inventors: 博穀田
Original assignee: 株式会社サトー; 株式会社サトー知識財産研究所
Priority date: 2008-12-24
Filing date: 2009-01-19
Publication date: 2010-07-01
Also published as: JP5123841B2; JP2010149324A

Abstract

There is provided a thermal printer capable of achieving a balance between left and right head pressure even when a support shaft is not in parallel with a platen roller due to the variations of components and assemblies and of ensuring a desired print quality even with an inexpensive component configuration. A pivotally supporting portion (82) is provided that straddles in the width direction of a medium to be printed and positions and supports a thermal head (12) in the carrying direction of the medium to be printed. The thermal head (12) is supported by the pivotally supporting portion (82) so as to be able to swing centered on the middle in the width direction, from side to side, in a direction perpendicular to a printing surface. Consequently, even when the pivotally supporting portion (82) is not in parallel with a platen roller (11) due to the variations of components and assemblies, the thermal head (12) is swung centered on the middle in the width direction and is pressed in parallel against the platen roller (11).

Description

Thermal printer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer that performs printing by pinching and conveying a printing medium between a platen roller and a thermal head, and more particularly to a thermal printer that positions a thermal head with respect to a platen roller by a support shaft that supports the thermal head. It is.

In a thermal printer that prints on a belt-like printing medium such as a continuous label that is temporarily attached to a belt-like mount using a conventional thermal head, the printing applied to the printing paper depending on the thickness and material of the printing paper Pressure may change and print quality may deteriorate. Therefore, a technique is known in which the thermal print head is moved to change the relative position between the thermal print head and the platen roller to optimally set an appropriate printing pressure. For example, the head housing to which the thermal head is fixed is rotatably held by the support shaft, and the head housing is held to be movable in the vertical direction upstream of the support shaft in the conveyance direction of the print medium. There has been proposed a thermal printer that can change the relative position of the thermal head and the platen roller with a simple operation without attaching and detaching (see, for example, Patent Document 1). *

However, in the prior art, since the thermal head is supported by the support shaft, there is a problem in that the quality of parts for ensuring the parallelism between the support shaft and the platen roller is required, and the apparatus becomes expensive. . Also, if the parts quality that ensures the parallelism between the support shaft and the platen roller is not ensured, the support shaft will not be parallel to the platen roller due to variations in parts and assembly, and the left / right balance of the head pressure will be lost, resulting in poor print quality. There was a problem that there was a possibility of doing. *

JP 2007-62211 A

The present invention has been made in view of such problems, and an object of the present invention is to be able to balance the left and right head pressures even when the support shaft is not parallel to the platen roller due to variations in parts and assembly. Therefore, the present invention is to provide a thermal printer that can ensure a desired print quality even with an inexpensive component configuration.

In order to solve the above problems, the present invention has the following configuration. The gist of the invention described in claim 1 is a thermal printer that performs printing by sandwiching and transporting a printing medium between a platen roller and a thermal head, and is suspended in the width direction of the printing medium. A support shaft for positioning and supporting the head in the transport direction of the print medium is provided, and the thermal head swings left and right around the center in the width direction in the direction perpendicular to the print surface by the support shaft. It exists in the thermal printer characterized by being supported. According to a second aspect of the invention, the thermal head is supported by the support shaft via a head housing, and the head housing is formed on both side surfaces, and the direction perpendicular to the printing surface is long. And a short hole direction substantially equal to the diameter of the support shaft, and a contact means for contacting the support shaft penetrating the long hole at the center in the width direction. The head housing is positioned and supported by the penetrating support shaft in the transport direction of the print medium, which is the short direction of the long hole, and the contact means is perpendicular to the print surface. The thermal printer according to claim 1, wherein the head housing is supported so as to be swingable left and right about the center. According to a third aspect of the present invention, the support shaft is rotatably supported, and a portion passing through the long hole of the head housing is eccentric with respect to the rotation shaft, 3. The thermal printer according to claim 2, wherein the thermal head is movable in the transport direction of the print medium by the rotation of the support shaft.

The thermal printer of the present invention is provided with a support shaft that spans in the width direction of the print medium and positions and supports the thermal head in the transport direction of the print medium. The thermal head is placed on the print surface by the support shaft. By configuring it so that it can swing left and right around the center in the width direction in the direction perpendicular to the center, even if the support shaft is not parallel to the platen roller due to variations in parts and assembly, the center in the width direction is the center The thermal head is swung and the thermal head is pressed in parallel with the platen roller, so that the right and left head pressure can be balanced, and the desired print quality can be achieved even with an inexpensive component configuration. There is an effect that it can be secured. *

Further, in the thermal printer of the present invention, the thermal head is supported by the support shaft via the head housing, the head housing is formed on each side surface, and the direction perpendicular to the printing surface is the longitudinal direction, and By providing a long hole whose short direction is substantially the same as the diameter of the support shaft and a contact means for contacting the support shaft penetrating the long hole at the center in the width direction, the short hole of the long hole can be formed with a simple configuration. The head housing (thermal head) can be positioned and supported in the print medium conveyance direction, and the head housing can swing left and right around the contact means in the direction perpendicular to the print surface. There is an effect that the (thermal head) can be supported. *

Furthermore, in the thermal printer of the present invention, the support shaft is rotatably supported, and the portion of the head housing penetrating through the long hole is decentered with respect to the rotation shaft. The thermal head can be moved in the conveyance direction of the print medium by the rotation, and the head position of the thermal head relative to the platen roller can be adjusted according to the thickness and material of the paper.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. *

FIG. 1 is a schematic side view showing a configuration of an embodiment of a thermal printer according to the present invention, and FIG. 2 is an external perspective view showing a closed state of the embodiment of the thermal printer according to the present invention. 3 is an external perspective view showing the open state of the embodiment of the thermal printer according to the present invention, and FIG. 4 is a perspective view showing the configuration of the head housing shown in FIG. 3, (a) and (b). These are front views seen from the front side, and (c) is a rear view seen from the rear side. 5 is a perspective view showing the configuration of the printing unit shown in FIG. 3, and FIG. 6 is a perspective view showing the configuration of the frame cover shown in FIG. *

In the thermal printer 10 of the present embodiment, referring to FIG. 1, a platen roller 11 as a printing unit and a surface on which a plurality of heating elements are formed in the width direction (hereinafter referred to as a printing surface) are the platen roller 11. A printing head 1 such as a label continuum in which a plurality of labels are temporarily attached to a belt-like mount and the ink ribbon 2, and a platen roller 11. It is configured so that printing is performed by transferring ink from the ink ribbon 2 to the print medium 1 by sandwiching and transporting it between the thermal head 12 and selectively generating heat from the heating element of the thermal head 12. *

The printing medium 1 is wound around a cylindrical body such as a paper tube, that is, is rotatably supported by a supply unit 13 as a roll paper 3, and the platen roller 11, the thermal head 12, Supplied during. The ink ribbon 2 is stretched between a ribbon take-up shaft 14 and a ribbon supply shaft 15 that are rotationally driven in conjunction with the platen roller 11, and is wound around the ribbon supply shaft 15 in a roll shape. The supported ink ribbon 2 is supplied together with the printing medium 1 between the platen roller 11 and the thermal head 12, and the transferred ink ribbon 2 is taken up by the ribbon take-up shaft 14. *

Further, the thermal printer 10 includes a platen roller 11 and a supply unit 13, a main body 20 whose upper part is released, an upper lid part 30 covering the upper part of the main body 20, a thermal head 12, a ribbon take-up shaft 14, and a ribbon supply shaft. 15, and a printing unit 40 disposed between the main body 20 and the upper lid portion 30. The upper lid portion 30 and the printing unit 40 are rotated by a support shaft 17 provided on the back side of the main body 20. It is supported so as to be movable, and is configured to open from a front side provided with a discharge port 16 through which a printed print medium is discharged. *

FIG. 2 shows the appearance of the thermal printer 10 in a closed state in which the upper lid portion 30 is closed. In the closed state, the printing unit 40 is sandwiched between the main body 20 and the upper lid portion 30 as shown in FIG. The thermal head 12 provided in the printing unit 40 is pressed against the platen roller 11 provided in the main body for positioning. Note that the printing unit 40 is configured to be fitted to the upper lid 30, and in the closed state shown in FIG. 2, the printing unit 40 is fitted to the upper lid 30. *

FIG. 3 shows the thermal printer 10 in an open state in which the upper lid 30 is opened, and the upper lid 30 and the printing unit 40 can be independently rotated. The upper lid portion 30 is configured to be maintained in the open state shown in FIG. 3 by the opening / closing stopper 31 even when the hand is released, and the printing unit 40 is formed on the convex portion 31a protruding inside the opening / closing stopper 31. When the arm portion 41 is caught, the arm unit 41 can be stopped independently from the printing unit 40 in the state shown in FIG. The upper lid portion 30 is provided with a contact member (not shown) that keeps the print unit 40 in a fitted state by contacting the print unit 40 with elasticity, and from the closed state shown in FIG. When the upper lid 30 is opened, the printing unit 40 is also rotated together with the upper lid 30 in the fitted state, and then the printing unit 40 is pulled out from the upper lid 30 to be in the open state shown in FIG. *

The thermal head 12 is configured to be assembled to the printing unit 40 while being supported by the head housing 60. Referring to FIG. 4, the head housing 60 includes a right side surface 62, a left side surface 64 parallel to the right side surface 62, and the ink ribbon 2 supplied between the platen roller 11 and the thermal head 12 from the ribbon supply shaft 15. And a lower surface 65 functioning as a guide surface for guiding. On the right side surface 62, when assembled in the printing unit 40, a circular supported recessed portion 61 a positioned on the upstream side in the transport direction of the print medium 1 with respect to the thermal head 12 (formed heating element) and the covered surface A circular supported recess 61b having the same diameter as the supported recess 61a is formed on the downstream side of the support recess 61a. Further, on the left side surface 64, when assembled to the printing unit 40, a circular supported projection 63a (located on the upstream side in the transport direction of the print medium 1 with respect to the thermal head 12 (formed heating element)). And a circular supported protrusion 63b having the same diameter as that of the supported protrusion 63a. The supported recessed portion 61a of the right side surface 62 and the supported projection 63a of the left side surface 64 are formed to face each other so that the axes coincide with each other, and the supported recessed portion 61b of the right side surface 62 and the left side surface are formed. The 64 supported protrusions 63b are formed to face each other so that the axes coincide with each other.

In addition, the thermal head 12 is fixed to the head housing 60, and when the head housing 60 is assembled to the printing unit 40 on the opposite side of the printing surface of the thermal head 12, the thermal housing 12 contacts a contact member described later. The pressing member 66 in contact with the printing surface is supported so as to be movable in a direction perpendicular to the printing surface, and a spring 67 is interposed between the thermal head 12 and the pressing member 66. Thereby, the thermal head 12 fixed to the head housing 60 is pressed against the platen roller 11 by the urging force of the spring 67. *

Further, on the right side surface 62 and the left side surface 64, when assembled to the printing unit 40, the supported concave portion is on the upstream side in the transport direction of the printing medium 1 with respect to the thermal head 12 (the heating element formed). Long holes 68 whose longitudinal direction is the direction perpendicular to the print surface are formed at positions opposed to the downstream side in the transport direction of the print medium 1 from 61a and the supported protrusion 63a. The long hole 68 is a through hole through which a support shaft, which will be described later, serving as a fulcrum shaft for supporting the head housing 60 is penetrated. By the support shafts penetrating the long holes 68 respectively formed on the right side surface 62 and the left side surface 64, The head housing 60 is positioned on the print unit 40 in the conveyance direction of the print medium 1, that is, in the short direction of the long hole 68. Further, a V-shaped protrusion 69 provided at the center in the width direction of the head housing 60 abuts on the support shaft that passes through the long hole 68, so that the head housing 60 is positioned at the center in the width direction in a direction perpendicular to the print surface. The printing unit 40 is positioned at one point. *

3 and 5, the print unit 40 has the ribbon winding shaft 14 and the ribbon supply shaft 15 rotatably mounted on the release end side of the arm portion 41 whose one end is supported by the support shaft 17. A right ribbon frame 42 and a left ribbon frame 43 are provided. The distance between the right ribbon frame 42 and the left ribbon frame 43 is set slightly wider than the width of the head housing 60, and the head housing 60 is assembled between the right ribbon frame 42 and the left ribbon frame 43. ing. Further, an abutting member 44 that presses the thermal head 12 against the platen roller 11 with a predetermined head pressure by contacting the pressing member 66 is provided above the assembled head housing 60, that is, on the pressing member 66 side. Yes. *

The left ribbon frame 43 is rotationally driven from the transmitted gear 46 to the ribbon take-up shaft 14 by being engaged with the transmission gear 21 rotated together with the platen roller 11 in the closed state shown in FIG. A driving force transmission mechanism (not shown) such as a gear for transmitting force is provided. Further, the opposed surface of the left ribbon frame 43 that faces the right ribbon frame 42 has a larger diameter than the supported projection 63 a formed on the left side surface 64 of the head housing 60, and the supported projection 63 a A circular support recess 47a to be loosely mounted and a circular support having a larger diameter than the supported protrusion 63b formed on the left side surface 64 of the head housing 60 and to which the supported protrusion 63b is loosely mounted. A concave portion 47b is formed. *

On the outer surface of the right ribbon frame 42 opposite to the opposite surface facing the left ribbon frame 43, a frame portion 48 perpendicular to the outer surface is formed at the peripheral edge, and the region surrounded by the frame portion 48 is The frame cover 70 shown in FIG. 6 functions as the fitted portion 49 and can be fitted and removed. The frame cover 70 is a resin plate-like member, and the shapes of the fitted portion 49 and the frame cover 70 are asymmetric, and the frame cover 70 has a unique orientation with respect to the fitted portion 49. It is fitted with. *

Referring to FIGS. 5 and 6, the ribbon winding shaft 14 and the ribbon supply shaft 15 extend through the right ribbon frame 42 in the fitted portion 49, and the frame cover 70 includes Through

holes

71 and 72 into which the ribbon take-up shaft 14 and the ribbon supply shaft 15 extending to the fitting portion 49 are inserted are formed. Therefore, even when the frame cover 70 is fitted to the fitted portion 49, the ribbon take-up shaft 14 and the ribbon supply shaft 15 can be operated. Note that the ribbon take-up shaft 14 and the ribbon supply shaft 15 are not extended to the fitted portion 49, and the through-

holes

71 and 72 are formed at locations corresponding to the ribbon take-up shaft 14 and the ribbon supply shaft 15. Then, it may be operated by a driver, a dedicated jig or the like. Further, when the driving force transmission mechanism does not become an obstacle, the ribbon take-up shaft 14 and the ribbon supply shaft 15 may be operated from the left ribbon frame 43 side. *

The right ribbon frame 42 positioned in the fitted portion 49 has through holes 50a at locations corresponding to the supported recessed portions 61a and the supported recessed portions 61b formed on the right side surface 62 of the head housing 60 to be assembled. And the through-hole 50b is formed, respectively. The frame cover 70 has a smaller diameter than the supported recessed portion 61 a formed on the right side surface 62 of the head housing 60, and the through hole 50 a is formed when the frame cover 70 is fitted to the fitted portion 49. A circular support protrusion 74 that penetrates and is loosely mounted on the supported recess 61 a and a smaller diameter than the supported recess 61 b formed on the right side surface 62 of the head housing 60. A circular support protrusion 75 is formed which is penetrated through the through hole 50b and loosely mounted on the supported recessed portion 61b when fitted to the fitted portion 49. *

Resin spring portions 76 that are displaced in a direction perpendicular to the frame portion 48 are formed on two sides of the side surface of the frame cover 70, that is, the surface facing the frame portion 48 when fitted, and the resin spring portion An engagement convex portion 77 is formed on 76, and the frame portion 48 is notched at a location facing the resin spring portion 76 so that the resin spring portion 76 of the frame cover 70 can be operated when fitted. 51 is formed, and in the vicinity of the notch 51, an engagement recess 52 that engages with the engagement projection 77 when the frame cover 70 is fitted is formed. In the present embodiment, the engagement recess 52 is formed as a through hole that penetrates the frame portion 48. *

On the opposite surface of the left ribbon frame 43 that faces the right ribbon frame 42, there is a circular support recess 47c that supports the support shaft 80, and the right ribbon frame 42 has a through hole 50c through which the support shaft 80 passes. Each is formed. The support shaft 80 is a fulcrum shaft that supports the head housing 60, and includes a rotation shaft 81 a that is fitted in a support recess 47 c formed in the left ribbon frame 43 and a through hole 50 c formed in the right ribbon frame 42. And has a rotation shaft 81b that is the same axis as the rotation shaft 81a. Further, in the support shaft 80, the rotation shaft 81 a and the rotation shaft 81 b are penetrated through a long hole 68 formed in the head housing 60 and a V-shaped protrusion 69 is in contact with the head housing 60. A column-shaped shaft support portion 82 is provided. The shaft support portion 82 has a diameter substantially the same as the short direction of the long hole 68, and positions the head housing 60 in the short direction of the long hole 68, that is, in the transport direction of the print medium 1. The shaft of the shaft support 82 is set to be different from the shafts of the rotation shaft 81a and the rotation shaft 81b, and the shaft support 82 functions as an eccentric member with respect to the rotation shaft 81a and the rotation shaft 81b. . An extension piece 83 extending from the rotation shaft 81b to the fitted portion 49 is formed, and an operation piece 84 for operating the rotation of the support shaft 80 is provided on the extension piece 83. Is formed. The frame cover 70 is provided with a moving space 78 in which the extension piece 83 can move, and an opening 79 for operating the operation piece 84. *

Next, the operation of assembling the head housing 60 to the printing unit 40 in the present embodiment will be described in detail with reference to FIGS. 7 to 9 are perspective views for explaining the assembly operation of the head housing to the printing unit shown in FIG. 3, and FIG. 10 shows a state in which the head housing is assembled to the printing unit shown in FIG. It is a perspective view. *

As shown in FIG. 7, the assembly of the head housing 60 including the thermal head 12 to the printing unit 40 is first performed by attaching the supported protrusion 63 a formed on the left side surface 64 of the head housing 60 to the left ribbon frame 43. The supporting recesses 47a formed on the opposing surface are loosened and the supported projections 63b formed on the left side surface 64 of the head housing 60 are supported on the opposing surfaces of the left ribbon frame 43. The head housing 60 is sandwiched at a predetermined position between the right ribbon frame 42 and the left ribbon frame 43 as shown in FIG. *

As a result, the left side surface 64 of the head housing 60 is substantially positioned with respect to the facing surface of the left ribbon frame 43, and the supporting recess 47 c formed on the facing surface of the left ribbon frame 43 is formed on the head housing 60. A state in which the long hole 68 formed in the left side surface 64 and the through hole 50c formed in the facing surface of the right ribbon frame 42 face the long hole 68 formed in the right side surface 62 of the head housing 60, respectively. Become. *

Next, the support shaft 80 is inserted from the through hole 50c formed in the opposing surface of the right ribbon frame 42 with the rotation shaft 81a as a tip, and the right shaft 62 and the left surface 64 of the head housing 60 are respectively inserted. The formed long hole 68 is penetrated, the rotating shaft 81a is formed in the supporting recess 47c formed on the facing surface of the left ribbon frame 43, and the rotating shaft 81b is formed on the facing surface of the right ribbon frame 42. Each through hole 50c is fitted. As a result, the support shaft 80 is spanned between the left ribbon frame 43 and the right ribbon frame 42 and positioned so as to be rotatable, and the head housing 60 is pivotally supported by the shaft support portion 82. *

Next, as indicated by an arrow in FIG. 9, the frame cover 70 is fitted to the fitted portion 49 while pressing the resin spring portion 76 formed on the side surface, and the resin spring portion 76 is released. As a result, the engaging convex portion 77 formed on the resin spring portion 76 is engaged with the engaging concave portion 52 formed on the frame portion 48, and the frame cover 70 is fitted to the fitting portion 49. Will be locked. *

In a state in which the frame cover 70 is fitted to the fitted portion 49, the supporting projection 74 formed on the frame cover 70 passes through the through hole 50a and is loosely mounted on the supported recessed portion 61a. A support protrusion 75 formed on the cover 70 passes through the through hole 50b and is loosely mounted on the supported recess 61b. *

Further, as shown in FIG. 10, the ribbon take-up shaft 14, the ribbon supply shaft 15 and the operation piece 84 extending to the fitted portion 49 have through

holes

71 and 72 formed in the frame cover 70 and openings. The ribbon take-up shaft 14, the ribbon supply shaft 15, and the operation piece 84 can be respectively operated through the through

holes

71 and 72 and the opening 79. *

The removal operation of the head housing 60 assembled to the print unit 40 is performed in the reverse procedure of the assembly operation of the head housing 60 to the print unit 40. That is, by engaging the resin spring portion 76 formed on the side surface of the frame cover 70 through the notch 51, the engagement convex portion 77 formed on the resin spring portion 76 and the engagement formed on the frame portion 48. The engagement with the concave portion 52 is released, and the frame cover 70 is removed from the fitted portion 49 while pressing the resin spring portion 76 formed on the side surface. Next, the head housing 60 can be removed from between the right ribbon frame 42 and the left ribbon frame 43 by removing the support shaft 80.

Next, the head position adjusting method in the present embodiment will be described in detail with reference to FIG. FIG. 11 is an explanatory diagram for explaining a head position adjusting method in the embodiment of the thermal printer according to the present invention. *

The thermal printer 10 according to the present embodiment can deal with sheets of different thicknesses and materials such as tags and labels as the print medium 1, and the head of the thermal head 12 with respect to the platen roller 11 according to the thickness and material of the sheets. The position can be adjusted. *

In the state where the head housing 60 is assembled to the printing unit 40, the positioning of the head housing 60 in the transport direction of the print medium 1 passes through the long holes 68 formed in the right side surface 62 and the left side surface 64 of the head housing 60, respectively. This is done by the support shaft 80. That is, since the shaft support portion 82 of the support shaft 80 has substantially the same diameter as the short direction of the long hole 68, the shaft support portion 82 of the support shaft 80 is passed through the long hole 68, so that the long hole 68. The head housing 60 is positioned in the short direction, that is, in the transport direction of the print medium 1. *

On the other hand, the axis of the shaft support portion 82 and the axes of the rotation shaft 81a and the rotation shaft 81b are set to be different, and the rotation shaft 81a is fitted into the support recess 47c formed in the left ribbon frame 43. The rotating shaft 81a is rotatably supported by being fitted into a through hole 50c formed in the right ribbon frame 42. *

Accordingly, as shown in FIGS. 11A and 11B, the shaft support 82 is operated by operating the operation piece 84 to rotate the support shaft 80 about the rotation shaft 81a and the rotation shaft 81b. The head housing 60, that is, the thermal head 12 moves in the conveyance direction of the print medium 1, and the head position of the thermal head 12 relative to the platen roller 11 is functioned as an eccentric member with respect to the rotation shaft 81 a and the rotation shaft 81 b. Can be adjusted. *

In the head housing 60, the supported recess 61a on the right side surface 62 and the supported projection 63a on the left side surface 64, whose axial centers coincide, are supported by the support projection 74 on the frame cover 70 and the support recess on the left ribbon frame 43. 47a, the supported recess 61b on the right side 62 and the supported projection 63b on the left side 64, which have the same axial center, are supported by the support projection 75 of the frame cover 70 and the left ribbon frame 43. Each of the concave portions 47b is loosely mounted, but the play in the conveyance direction of the print medium 1 is set to be greater than the movement range for adjusting the head position. *

Next, the head pressure left / right balance automatic adjustment function in the present embodiment will be described in detail with reference to FIG. FIG. 12 is an explanatory diagram for explaining the head pressure left / right balance automatic adjustment function in the embodiment of the thermal printer according to the present invention. *

Referring to FIG. 12A, in the state where the head housing 60 is assembled to the printing unit 40, the positioning of the head housing 60, that is, the thermal head 12 in the direction perpendicular to the printing surface is performed by the shaft support portion of the support shaft 80. The thermal head 12 is positioned at one point in the center in the width direction by contacting the V-shaped protrusion 69 provided in the center in the width direction of the head housing 60 with 82. *

In addition, the long holes 68 formed in the right side surface 62 and the left side surface 64 of the head housing 60 through which the support shaft 80 penetrates have a longitudinal direction perpendicular to the print surface. The thermal head 12 is supported so as to be swingable left and right around the V-shaped protrusion 69 at the center in the width direction. *

Accordingly, even when the thermal head 12 is not assembled in parallel to the platen roller 11 when the head housing 60 (thermal head 12) is assembled to the printing unit 40, as shown in FIG. Further, the thermal head 12 is swung around the V-shaped protrusion 69, and the thermal head 12 is pressed in parallel against the platen roller 11. *

Further, even if the shaft support portion 82 of the support shaft 80 is not parallel to the platen roller 11 due to variations in parts and assembly, as shown in FIGS. 12B and 12C, the V-shaped projection 69 is the center. The thermal head 12 is swung and the thermal head 12 is pressed in parallel against the platen roller 11. *

As described above, according to the present embodiment, the support shaft 80 (the shaft support portion 82) spans in the width direction of the print medium 1 and positions and supports the thermal head 12 in the transport direction of the print medium 1. ) And the thermal head 12 is supported by the support shaft 80 (axial support portion 82) so as to be swingable left and right around the center in the width direction in the direction perpendicular to the printing surface. Even when the support shaft 80 (the shaft support portion 82) is not parallel to the platen roller 11 due to variations in parts and assembly, the thermal head 12 is swung around the center in the width direction, and the thermal head 12 is parallel to the platen roller 11. Because it is pressed, the head pressure can be balanced right and left, and the desired print quality can be ensured even with an inexpensive component structure. An effect that theft can be. *

Further, according to the present embodiment, the thermal head 12 is supported by the support shaft 80 via the head housing 60, and the head housing 60 is formed on the right side surface 62 and the left side surface 64, respectively, and is formed on the printing surface. A long hole 68 whose vertical direction is the longitudinal direction and whose short direction is substantially the same as the diameter of the support shaft 80, and a V-shaped protrusion 69 that abuts the support shaft 80 penetrating the long hole 68 at the center in the width direction. By providing, the head housing 60 (thermal head 12) can be positioned and supported in the transport direction of the print medium 1 that is the short direction of the long hole 68 with a simple configuration, and also with respect to the print surface. There is an effect that the head housing 60 (thermal head 12) can be supported so as to be able to swing left and right around the V-shaped projection 69 in the vertical direction. That. *

Furthermore, according to the present embodiment, the support shaft 80 is rotatably supported, and the portion passing through the long hole 68 of the head housing 60 is decentered with respect to the

rotation shafts

81a and 81b. Thus, the thermal head 12 can be moved in the transport direction of the printing medium 1 by the rotation of the support shaft 80, and the head position of the thermal head 12 with respect to the platen roller 11 can be adjusted according to the thickness and material of the paper. There is an effect that can be done. *

Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a number, position, shape, and the like that are suitable for implementing the present invention. In each figure, the same numerals are given to the same component.

1 is a schematic side view showing a configuration of an embodiment of a thermal printer according to the present invention. 1 is an external perspective view showing a closed state of an embodiment of a thermal printer according to the present invention. 1 is an external perspective view showing an open state of an embodiment of a thermal printer according to the present invention. FIG. 4 is a perspective view showing the configuration of the head housing shown in FIG. 3, wherein (a) and (b) are front views as seen from the front side, and (c) are rear views as seen from the rear side. FIG. 4 is a perspective view illustrating a configuration of a printing unit illustrated in FIG. 3. It is a perspective view which shows the structure of the frame cover shown in FIG. FIG. 4 is a perspective view for explaining an assembly operation of the head housing to the printing unit shown in FIG. 3. FIG. 4 is a perspective view for explaining an assembly operation of the head housing to the printing unit shown in FIG. 3. FIG. 4 is a perspective view for explaining an assembly operation of the head housing to the printing unit shown in FIG. 3. FIG. 4 is a perspective view illustrating a state in which a head housing is assembled to the printing unit illustrated in FIG. 3. It is explanatory drawing for demonstrating the head position adjustment method in embodiment of the thermal printer which concerns on this invention. It is explanatory drawing for demonstrating the left-right balance automatic adjustment function of the head pressure in embodiment of the thermal printer which concerns on this invention.

Explanation of symbols

1 Print medium 2 Ink ribbon 3 Roll paper 10 Thermal printer 11 Platen roller 12 Thermal head 13 Supply unit 14 Ribbon take-up shaft 15 Ribbon supply shaft 16 Discharge port 17 Support shaft 20 Main body 30 Upper lid 31 Opening / closing stopper 31a Protrusion 40 Printing Unit 41 Arm part 42 Right ribbon frame 43 Left ribbon frame 44 Contact member 46 Transmitted

gear

47a, 47b, 47c Support recess 48 Frame 49

Fit part

50a, 50b, 50c Through hole 51 Notch 52 Engagement recess 60

Head housing

61a, 61b Recessed recess 62

Right side

63a, 63b Supported protrusion 64 Left side 65 Lower surface 66 Pressing member 67 Spring 68 Hole 69 V-shaped projection 70 frame cover 71 through

holes

74 and 75 supporting projection 76 resin spring portion 77 engaging portion 80 supporting the

shaft

81a, 81b pivot shaft 82 the shaft support 83 extending piece 84 operating piece

Claims

A thermal printer that performs printing by sandwiching and transporting a printing medium between a platen roller and a thermal head, spanning in a width direction of the printing medium, and moving the thermal head in a conveyance direction of the printing medium It comprises a support shaft that is positioned and supported, and the thermal head is supported by the support shaft so as to be able to swing left and right around the center in the width direction in a direction perpendicular to the printing surface. Thermal printer.
The thermal head is supported by the support shaft via a head housing, and the head housing is formed on both side surfaces, the direction perpendicular to the printing surface is the longitudinal direction, and the short direction is the support shaft. And a contact means for contacting the support shaft penetrating through the long hole at the center in the width direction, and the long hole is formed by the support shaft penetrating the long hole. The head housing is positioned and supported in the transport direction of the medium to be printed, which is the short direction of the head, and the head housing is swingable left and right around the contact means in a direction perpendicular to the print surface. The thermal printer according to claim 1, wherein the housing is supported.
The support shaft is rotatably supported, and a portion passing through the long hole of the head housing is eccentric with respect to the rotation shaft, and the thermal head rotates the support shaft. The thermal printer according to claim 2, wherein the thermal printer is movable in the transport direction of the print medium.