Inkjet unit, thermal printer

Abstract

The printing unit includes a platen roller that conveys a recording paper, a thermal head that is pressed against a circumferential surface of the platen roller and prints on the recording paper (P), and a paper guide portion that inserts the recording paper (P) from an acute angle direction toward a printing region of the thermal head.

Description

Technical Field

[0001] This invention relates to printing units and thermal printers. Background Technology

[0002] Regarding the printing unit of a previously known thermal printer, the printing roller is rotated while the recording paper is clamped between the printing roller and the thermal head. This feeds the recording paper while the heating element of the thermal head heats the printing surface of the paper, causing the printing surface to develop color and thus printing the text.

[0003] In the aforementioned printing unit, the recording paper is guided by a roughly cuboid-shaped support at the front of the thermal head, changing its orientation by 90° and inserting it into the printing area of ​​the thermal head. Therefore, applying strong bending to the recording paper, for example when using die-cut label paper, may cause the label to peel off under certain temperature conditions (e.g., below 5°C where the label's adhesiveness decreases).

[0004] This invention was made in view of the above aspects, and its purpose is to provide a printing unit and a thermal printer capable of printing without applying strong bending to the recording paper. Summary of the Invention

[0005] One aspect of the present invention relates to a printing unit comprising: an impression roller for conveying recording paper; a thermal head for pressing against the circumferential surface of the impression roller and printing on the recording paper; and a paper guide for inserting the recording paper into the printing area of ​​the thermal head from an acute angle.

[0006] In one aspect of the present invention, the paper guide portion is inserted into the recording paper at an acute angle of 57.5° or less toward the printing area.

[0007] In one aspect of the present invention, the printing unit includes a motor that rotates the impression roller. The motor has a circumferential surface that guides the recording paper. The paper guide portion inserts the recording paper toward the printing area at an acute angle above the angle of the tangent to the circumferential surface of the motor.

[0008] In one aspect of the present invention, the paper guide portion has a guide slope with an opening, and the printing unit includes: a sensor disposed in the opening and detecting the recording paper; and a sensor holder that can be detachably engaged with the opening and tilted along the guide slope to hold the sensor.

[0009] In one embodiment of the present invention, the aforementioned sensor is disposed on a flexible printed circuit board, and the aforementioned sensor holder has a first inclined portion and a second inclined portion, the first inclined portion and the second inclined portion holding the aforementioned flexible printed circuit board on both sides of the aforementioned sensor, thereby indirectly holding the aforementioned sensor via the aforementioned flexible printed circuit board.

[0010] In a printing unit according to one aspect of the present invention, a recess is formed in either the first inclined portion or the second inclined portion, which is recessed relative to the inner wall surface of the opening and corresponds to the thickness of the flexible printed circuit board.

[0011] In one aspect of the present invention, the aforementioned sensor holder has a locking portion in the space on the back side of the aforementioned sensor between the aforementioned first inclined portion and the aforementioned second inclined portion, which can be detachably engaged with respect to the aforementioned opening.

[0012] In one aspect of the present invention, the printing unit has a plurality of peelable labels.

[0013] One aspect of the present invention relates to a thermal printer that includes the previously described printing unit. Attached Figure Description

[0014] Figure 1 This is a perspective view of a thermal printer involved in one implementation method.

[0015] Figure 2 This is a top view of a recording paper according to one embodiment.

[0016] Figure 3 This is a front side perspective view of a printing unit according to one embodiment.

[0017] Figure 4 This is an exploded perspective view of the front side of a printing unit according to one embodiment.

[0018] Figure 5 This is a perspective view of the back side of a printing unit according to one embodiment.

[0019] Figure 6 This is a front view of a printing unit involved in one implementation method.

[0020] Figure 7 yes Figure 6 The view shown is a cross-sectional view of VII-VII.

[0021] Figure 8 This is an exploded perspective view of the electronic components of a printing unit according to one embodiment.

[0022] Figure 9This is a front-side perspective view of a sensor holder according to one embodiment.

[0023] Figure 10 This is a front view of a sensor holder according to an implementation method.

[0024] Figure 11 This is a top view of a sensor holder according to one embodiment.

[0025] Figure 12 This is a bottom view of a sensor holder according to an implementation method.

[0026] Figure 13 This is a left-side view of a sensor holder according to one embodiment.

[0027] Figure 14 This is a right-side view of a sensor holder according to one embodiment. Detailed Implementation

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0029] Figure 1 This is a perspective view of a thermal printer 1 according to one embodiment. Figure 1 As shown, the thermal printer 1 is configured to print on recording paper P. The recording paper P is a heat-sensitive paper that develops color when heated, and is suitable for use in printing various labels, receipts, tickets, etc. The recording paper P is placed in the thermal printer 1 in the form of a roll of paper R (wound in a manner having hollow holes), and the portion pulled out from the roll of paper R is printed.

[0030] The thermal printer holder 1 has a housing 3, a display unit 4, a control unit 5, and a printing unit 10. The housing 3 is formed into a hollow box shape using plastic or metal materials such as ABS (acrylonitrile-styrene-butadiene copolymer) or a composite material of ABS and polycarbonate. The housing 3 has a cuboid main body 6 and a paper roll receiving part 7, the paper roll receiving part 7 protruding from one end of the main body 6 in the length direction to one side in the thickness direction of the main body 6.

[0031] A printing unit 10 is housed at one end of the main body 6 along its length. Additionally, a discharge port 3a is formed on the end face of one end of the main body 6 along its length. The discharge port 3a discharges recording paper P printed by the printing unit 10. A display unit 4 is disposed on the main surface of the main body 6 opposite to the paper roll receiving section 7 in its thickness direction. The display unit 4 is, for example, a liquid crystal panel, connected to the control unit 5, and displays various information. A roll of paper R is housed in the paper roll receiving section 7.

[0032] Figure 2 This is a top view of the recording paper P according to one embodiment. (Example) Figure 2 As shown, the recording paper P has multiple peelable labels P1. Each label P1 is a rectangular portion of a heat-sensitive layer bonded to a release paper P3 (base paper) opposite the printed side of the recording paper P, and multiple labels P1 are formed with gaps along the length of the recording paper P. A frame-like liner P2 is formed around each label P1. Labels P1 can be peeled off from the release paper P3 while retaining the liner P2. Thus, the recording paper P of this embodiment is a label release paper with a liner P2.

[0033] Figure 3 This is a front side perspective view of the printing unit 10 according to one embodiment. Figure 4 This is an exploded perspective view of the front side of the printing unit 10 according to one embodiment. Figure 5 This is a rear perspective view of the printing unit 10 according to one embodiment. (See attached image.) Figure 3 As shown, the printing unit 10 includes: an impression roller 51 having a driven gear 56; a motor 61 that rotates the impression roller 51; a main frame 11 that rotatably supports the impression roller 51 and assembles the motor 61; a first reduction gear 65 and a second reduction gear 66 that reduce the driving force of the motor 61 and transmit it to the driven gear 56; and a thermal head 41 that presses against the circumferential surface of the impression roller 51.

[0034] The printing unit 10 ejects the recording paper P between the impression roller 51 and the thermal head 41 in the direction indicated by arrow A. Hereinafter, primarily in the description of the printing unit 10, the direction along arrow A will be defined as the vertical direction L1. Furthermore, the axial direction extending from the rotation axis of the impression roller 51 and orthogonal to the vertical direction L1 will be defined as the horizontal direction L2. Moreover, the direction orthogonal to both the vertical direction L1 and the horizontal direction L2 will be defined as the front-back direction L3.

[0035] Furthermore, in the vertical direction L1, the side where the recording paper P is discharged (the side indicated by arrow A) is defined as top, and the opposite side is defined as bottom. In the horizontal direction L2, the side where the motor 61 is located is defined as right, and the opposite side is defined as left. In the front-back direction L3, the side where the impression roller 51 is located is defined as front, and the opposite side where the thermal head 41 is located is defined as rear.

[0036] The main frame 11 is formed using a sheet material such as polycarbonate resin containing glass fiber. The main frame 11 is formed in a U-shape that opens forward when viewed from the vertical direction L1. Specifically, the main frame 11 has: a back plate portion 12 that extends in the horizontal direction L2; a first side wall portion 13 that is erected facing forward from one side (left side) of the back plate portion 12 in the horizontal direction L2; a second side wall portion 14 that is erected facing forward and downward from the other side (right side) of the back plate portion 12 in the horizontal direction L2; and a washi paper guide portion 20 that is disposed between the first side wall portion 13 and the second side wall portion 14.

[0037] The back plate portion 12 is formed as a plate with thickness in the front-rear direction L3. The first side wall portion 13 is formed as a plate with thickness in the left-right direction L2. A first roller insertion groove 16A that cuts downward is formed at the upper edge of the first side wall portion 13. The second side wall portion 14 is formed as a plate with thickness in the left-right direction L2. A second roller insertion groove 16B that cuts downward is formed at the upper edge of the second side wall portion 14.

[0038] The second roller insertion groove 16B is formed in a manner consistent with the first roller insertion groove 16A in shape and formation position when viewed from the left-right direction L2. The impression roller 51 can be detachably inserted into the first roller insertion groove 16A and the second roller insertion groove 16B. The second sidewall portion 14 extends forward from the end of the back plate portion 12 on the other side (right side) in the left-right direction L2, and further extends downward.

[0039] A motor 61 is mounted in the second sidewall portion 14, lower than the connection between the second sidewall portion 14 and the backplate portion 12. The motor 61 is mounted inside the second sidewall portion 14 in the left-right direction L2, and its output shaft 61A passes through the second sidewall portion 14 and protrudes outward in the left-right direction L2. The motor 61 is connected to the control unit 5 (see reference 5) via a flexible printed circuit board 71 with a wiring pattern (not shown). Figure 1 Motor 61 is driven by signals from control unit 5.

[0040] A gearbox portion 17 is formed on the outer side of the second side wall portion 14. The gearbox portion 17 has a peripheral wall portion 18 that is erected on the outer side of the second side wall portion 14 in the left-right direction L2. The peripheral wall portion 18 is formed in a U-shape that opens upward when viewed from the left-right direction L2. The gearbox portion 17 opens outward in the left-right direction L2.

[0041] A downward-facing recess 19 is formed on the upper edge of the front side and the upper edge of the rear side of the peripheral wall portion 18. The pair of recesses 19 are formed in a manner that their shape and position are consistent when viewed from the front-rear direction L3. In addition, a hole 18a is formed in the lower part of the peripheral wall portion 18. A cover member (not shown) covering the gearbox portion 17 engages with these pair of recesses 19 and holes 18a.

[0042] A first reduction gear 65 and a second reduction gear 66 are assembled inside the gearbox section 17. For example... Figure 4 As shown, the first reduction gear 65 is rotatably supported by a first rotating shaft 67 erected from the second sidewall portion 14. The first reduction gear 65 meshes with the output shaft 61A of the motor 61. The second reduction gear 66 is rotatably supported above the first rotating shaft 67 by a second rotating shaft 68 erected from the second sidewall portion 14. The second reduction gear 66 meshes with the first reduction gear 65.

[0043] The paper guide portion 20 is formed as a roughly right-angled triangular column extending along the left-right direction L2. Regarding the paper guide portion 20, one end (left side) in the left-right direction L2 is connected to the inner surface of the first sidewall portion 13, and the other end (right side) in the left-right direction L2 is connected to the inner surface of the second sidewall portion 14. A pair of mounting portions 20a are formed in the paper guide portion 20, which are recessed downwards when viewed from the front-rear direction L3.

[0044] A pair of mounting portions 20a are formed with a gap in the left-right direction L2. A through hole 20b is provided at the bottom of each mounting portion 20a, penetrating the bottom of the mounting portion 20a in the vertical direction. The main frame 11, with bolts or other fastening components inserted through the through hole 20b of the paper guide portion 20, is positioned relative to the outer casing 3 (see reference). Figure 1 )Install.

[0045] Thermal head 41 pairs of recording paper P (reference) Figure 3 Printing is performed. The thermal head 41 is rectangular in shape when viewed from the front-to-back direction L3, with its length direction L2. The thermal head 41 is configured so that its length direction is consistent with the width direction of the recording paper P. On the head surface 41a of the thermal head 41, a plurality of heating elements 42 are arranged in the left-to-right direction L2.

[0046] The thermal head surface 41a faces the printing surface of the recording paper P and can hold the recording paper P between itself and the outer circumferential surface of the impression roller 51. The thermal head 41 is connected to the control unit 5 (see reference 5) via a flexible printed circuit board 71. Figure 1 The driver IC (not shown), mounted on the thermal printhead 41, controls the heating element 42 to heat up based on signals from the control unit 5. Regarding the thermal printhead 41, the heating element 42 is controlled to heat up, thus printing various texts or graphics onto the printing surface of the recording paper P.

[0047] The thermal head 41 is adhered and fixed to the head support 45, which is supported by the main frame 11. The head support 45 is a plate-shaped component with a length L2 in the left-right direction, and the thermal head 41 is adhered and fixed to its front surface. The head support 45 is disposed between the first side wall portion 13 and the second side wall portion 14, and between the back plate portion 12 and the paper guide portion 20 (see below). Figure 7 ).

[0048] like Figure 5 As shown, an elastic member 46 is installed intermediary between the head support 45 and the back plate portion 12, biased in a direction that separates the head support 45 and the back plate portion 12 from each other. That is, the elastic member 46 is configured to always press the head support 45 forward. Multiple elastic members 46 are arranged at intervals in the left-right direction L2 (three in this embodiment).

[0049] like Figure 4 As shown, a pair of stops 45a are formed at the upper end of the head support 45 to limit the rotation range of the head support 45. The pair of stops 45a are formed in a generally quadrangular prism shape and extend outward in the left-right direction L2 of the head support 45. The pair of stops 45a are inserted into rectangular holes 13a formed in the upper part of the first side wall portion 13 of the main frame 11 and rectangular holes 14a formed in the upper part of the second side wall portion 14. The stops 45a move within the holes 13a and 14a as the head support 45 rotates, and are configured to contact the inner wall surfaces of the holes 13a and 14a. The stops 45a contact the inner wall surfaces of the holes 13a and 14a, thereby limiting the amount of rotation of the head support 45.

[0050] like Figure 3 As shown, the impression roller 51 is positioned opposite the thermal head 41 and rotates with recording paper P sandwiched between it and the thermal head 41, thereby feeding the recording paper P in the direction indicated by arrow A. The impression roller 51 has a roller shaft 52, a roller body 53 externally mounted on the roller shaft 52, and a pair of bearings 54 mounted at both ends of the roller shaft 52. The roller shaft 52 is formed to be slightly longer than the separation distance between the first sidewall portion 13 and the second sidewall portion 14 of the main frame 11. The roller body 53 is formed of, for example, rubber, and is uniformly arranged along the left-right direction L2 throughout the roller shaft 52 except for the two ends.

[0051] Regarding the impression roller 51, a pair of bearings 54 mounted at both ends are inserted into the first roller insertion groove 16A and the second roller insertion groove 16B of the main frame 11. Thus, the impression roller 51 can rotate relative to the main frame 11 and can be detachably held. With the impression roller 51 inserted into the first roller insertion groove 16A and the second roller insertion groove 16B, the roller body 53 is set to contact the thermal head 41, and the roll paper R (refer to...) is drawn from the roll paper R... Figure 1 The pulled-out recording paper P is sandwiched between them.

[0052] like Figure 3 As shown, a driven gear 56 is fixed to the end of the impression roller 51 on the other side (right side) in the left-right direction L2. When the impression roller 51 is held by the first sidewall portion 13 and the second sidewall portion 14, the driven gear 56 is assembled to the upper part of the gearbox portion 17. At this time, the driven gear 56 overlaps with the second reduction gear 66 when viewed from the left-right direction L2, and is positioned further inward than the second reduction gear 66, meshing with the second reduction gear 66. Thus, the rotational driving force from the motor 61 is transmitted to the driven gear 56 via the first reduction gear 65 and the second reduction gear 66. The impression roller 51 can rotate in the state held by the first sidewall portion 13 and the second sidewall portion 14, feeding out the recording paper P (see reference). Figure 2 ).

[0053] Figure 6 This is a front view of the printing unit 10 according to one embodiment. Figure 7 yes Figure 6 The diagram shows a cross-sectional view of VII-VII. Figure 8 This is an exploded perspective view of the front side of the electronic components of the printing unit 10 according to one embodiment. (See attached image.) Figure 7 As shown in the figure, the paper guide 20 has a guide slope 21 that is inserted into the recording paper P from an acute angle toward the printing area 100 of the thermal head 41.

[0054] Here, the printing area 100 refers to the area on the head surface 41a of the thermal head 41, which is equipped with the heating element 42, and which faces the impression roller 51. In a narrower sense, the printing area 100 refers to the area in the head surface 41a that is pressed against the circumferential surface of the impression roller 51. In this embodiment, the printing area 100 is a planar area extending in the vertical direction L1 and the horizontal direction L2.

[0055] The guide slope 21 is inclined at an angle θ1 relative to the printing area 100. When the printing area 100 is set to 0° of the reference plane, the angle θ1 becomes an acute angle less than 90°. An acute angle θ1 of 57.5° or less is sufficient. This prevents excessive bending of the recording paper P and avoids marking P1 (see reference). Figure 2Peel off the paper and insert the recording paper P into the printing area 100. That is, the upper limit of angle θ1 is 57.5°.

[0056] On the other hand, the lower limit of angle θ1 can be angle θ2. Angle θ2 is the angle formed by the tangent 101 of the circumferential surface 61a of the motor 61 drawn from the printing area 100 with respect to the printing area 100. Figure 3 As shown, the circumferential surface 61a of the motor 61 is positioned within the paper path of the recording paper P, guiding the recording paper P. If angle θ1 is less than angle θ2, the recording paper P floats relative to the guide ramp 21, which is therefore undesirable. That is, the guide ramp 21 should be tilted relative to the printing area 100 at an angle greater than angle θ2.

[0057] In this embodiment, the guide slope 21 is inclined at an acute angle of 37.5° relative to the printing area 100. By setting the guide slope 21 to 37.5°, the minimum internal space required for arranging the sensor 81 (described later) in the paper guide section 20 can be ensured. Thus, the angle θ1 is greater than or equal to angle θ2 and less than 57.5°, and more preferably greater than or equal to 37.5° and less than 57.5°.

[0058] like Figure 6 As shown, an opening 22 for arranging the sensor 81 is formed in the guide slope 21. The opening 22 is T-shaped when viewed from the front. The opening 22 is arranged between a pair of mounting portions 20a in the left-right direction of the guide slope 21. The opening 22 is arranged between the pair of mounting portions 20a closer to the left side (left side) of the mounting portion 20a in the left-right direction.

[0059] A sensor 81 for detecting the recording paper P is disposed at the opening 22. In this embodiment, the sensor 81 is a light reflector. Alternatively, the sensor 81 can be a non-contact sensor other than a light reflector. Furthermore, the sensor 81 can also be a contact sensor. Figure 8 As shown in the figure, sensor 81 is disposed on flexible printed substrate 71.

[0060] The flexible printed circuit board 71 includes: a head connector 72 connected to a heating element 42, a motor connector 73 connected to a motor 61, and a sensor connector 74 connected to a sensor 81. The sensor connector 74 and the sensor 81, together with a sensor holder 91, are inserted into the bottom surface of the paper guide 20 through an opening 22. The sensor holder 91 is a resin-molded part that can be detachably engaged with the opening 22 of the paper guide 20.

[0061] Figure 9 This is a front side perspective view of a sensor holder 91 according to one embodiment. Figure 10This is a front view of a sensor holder 91 according to an embodiment. Figure 11 This is a top view of a sensor holder 91 according to an embodiment. Figure 12 This is a bottom view of a sensor holder 91 according to an embodiment. Figure 13 This is a left-side view of a sensor holder 91 according to one embodiment. Figure 14 This is a right-side view of a sensor holder 91 according to one embodiment. (See attached image.) Figure 9 As shown, the sensor holder 91 includes a base 92, a first inclined portion 93A, a second inclined portion 93B, and an engaging portion 94.

[0062] like Figure 9 and Figure 10 As shown, the base 92 is formed as a plate with thickness in the vertical direction L1. Figure 11 As shown, the base 92 connects the inner surfaces of the first inclined portion 93A and the second inclined portion 93B in the left-right direction L2. A rib 92a is erected on the upper surface of the base 92 to improve its bending stiffness. The rib 92a also extends in the left-right direction L2, connecting the inner surfaces of the first inclined portion 93A and the second inclined portion 93B in the left-right direction L2.

[0063] The first inclined surface 93A is in Figure 13 The left side shown in the diagram is formed into a roughly right-angled triangle shape. Additionally, the second beveled section 93B... Figure 14 The right side shown in the diagram also forms a roughly right-angled triangle shape. The first beveled surface 93A and the second beveled surface 93B are inclined at the same angle. Furthermore, as... Figure 12 As shown, thinning portions 97 for resin molding are formed on the bottom surfaces of the first inclined portion 93A and the second inclined portion 93B. Figure 9 As shown, the first inclined portion 93A and the second inclined portion 93B are configured with an open space in the left-right direction L2. This space has a dimension in the left-right direction L2 that allows the sensor 81 to be configured.

[0064] The first inclined portion 93A and the second inclined portion 93B hold the sensor connection portions 74 on both sides of the sensor 81 in the flexible printed circuit board 71, thereby indirectly holding the sensor 81 via the flexible printed circuit board 71. Furthermore, as... Figure 8 As shown, in the paper guide portion 20, a pair of clamping portions 23 are formed between the first inclined portion 93A and the second inclined portion 93B to clamp the flexible printed circuit board 71 (sensor connection portion 74). The pair of clamping portions 23 extend from the upper opening edge of the opening 22 of the paper guide portion 20 toward the inside of the opening 22.

[0065] A pair of cutouts 74b are formed at the upper ends of both sides of the sensor connection portion 74 in the left-right direction L2. A pair of shoulders 95, descending one level from the top of the sensor holder 91, are formed at the positions corresponding to the first inclined portion 93A and the second inclined portion 93B. The pair of shoulders 95 are disposed on the back side of the guide inclined surface 21, and their upper surfaces abut against the top surface inside the paper guide portion 20, thereby positioning the sensor holder 91 in the up-down direction L1.

[0066] The engaging portion 94 can be detachably engaged with the engaging portion 24 formed on the inner wall surface behind the opening 22. For example... Figure 9 and Figure 11 As shown, the engaging portion 94 is disposed between the first inclined portion 93A and the second inclined portion 93B in the left-right direction L2, and is continuously disposed with respect to the rear side of the base 92. The engaging portion 94 extends rearward from the base 92 and then bends upward, and has a protrusion (hook) protruding rearward at its upper end. The engaging portion 94 is elastically deformable back and forth in the space between the first inclined portion 93A and the second inclined portion 93B.

[0067] like Figure 7 As shown, the engaging portion 94 engages with the engaged portion 24. Thus, the sensor holder 91 is assembled to the paper guide portion 20. In the sensor holder 91, a recess 96 is formed on the inner wall surface 22a opposite to the front side of the opening 22, corresponding to the thickness of the flexible printed circuit board 71. Figure 9 As shown, a recess 96 is formed at the lower front end of the second inclined portion 93B. A recess 96 is provided with... Figure 8 The sensor connection portion 74 shown is a strip-shaped portion 74a. As a result, the wiring pattern formed on the strip-shaped portion 74a can be prevented from being damaged when sandwiched between the sensor holder 91 and the inner wall surface 22a of the opening 22.

[0068] As explained above, the printing unit 10 of this embodiment includes: an impression roller 51 that conveys recording paper P; a thermal head 41 that presses against the circumferential surface of the impression roller 51 and prints on the recording paper P; and a paper guide 20 that inserts the recording paper P into the printing area 100 of the thermal head 41 from an acute angle. Therefore, the recording paper P can be inserted into the printing area 100 without subjecting it to excessive bending. Consequently, peeling of the label P1 on the recording paper P can be prevented. Furthermore, the paper guide 20 is thinner than the previous prism-shaped paper guide, thus contributing to the miniaturization and space-saving of the device.

[0069] In addition, in this embodiment, such as Figure 7As shown, the paper guide 20 is inserted into the recording paper P at an acute angle of 57.5° or less toward the printing area 100. With this configuration, even under specific temperature conditions (e.g., below 5°C where the adhesiveness of the label decreases), peeling of the label P1 from the recording paper P can be prevented.

[0070] Furthermore, in this embodiment, a motor 61 is provided to rotate the impression roller 51. The motor 61 has a circumferential surface 61a for guiding the recording paper P. The paper guide 20 is inserted into the recording paper P at an acute angle θ1 above the tangent 101 of the circumferential surface 61a leading from the printing area 100 to the printing area 100. With this configuration, floating of the recording paper P can be prevented, thus preventing wrinkles or the like from forming on the printed recording paper P.

[0071] In this embodiment, the paper guide portion 20 has a guide slope 21 with an opening 22, and includes: a sensor 81 disposed in the opening 22 and detecting the recording paper P; and a sensor holder 91 that can be detachably engaged with the opening 22 and holds the sensor 81 at an angle along the guide slope 21. With this configuration, the sensor 81 can be easily disposed along the guide slope 21, which is inclined relative to the printing area 100.

[0072] In addition, in this embodiment, such as Figure 8 As shown, sensor 81 is disposed on flexible printed circuit board 71, and sensor holder 91 has a first inclined portion 93A and a second inclined portion 93B. The first inclined portion 93A and the second inclined portion 93B hold the flexible printed circuit board 71 on both sides of sensor 81, thereby indirectly holding sensor 81 via flexible printed circuit board 71. According to this configuration, due to the influence of the unevenness of terminals, etc. of sensor 81, sensor holder 91 can prevent sensor 81 from holding in an inclined state.

[0073] In addition, in this embodiment, such as Figure 7 As shown, in either the first inclined portion 93A or the second inclined portion 93B (in this embodiment, the second inclined portion 93B), a recess 96 is formed that is recessed relative to the inner wall surface 22a of the opening 22, corresponding to the thickness of the flexible printed circuit board 71. With this configuration, damage can be avoided to the strip-shaped portion 74a of the flexible printed circuit board 71, which is inserted into the opening 22 together with the sensor holder 91.

[0074] Furthermore, in this embodiment, the sensor holder 91 has a locking portion 94 in the space S on the back side of the sensor 81 between the first inclined portion 93A and the second inclined portion 93B, which can be detachably engaged with respect to the opening 22. With this configuration, the locking portion 94 can be elastically deformed in the front-rear direction using the space S on the back side of the sensor 81 between the first inclined portion 93A and the second inclined portion 93B, making it easier to detach and assemble the sensor holder 91 relative to the opening 22.

[0075] In addition, in this embodiment, such as Figure 2 As shown, the recording paper P has multiple peelable labels P1. This configuration prevents the labels P1 from peeling off along the paper's path.

[0076] Furthermore, the thermal printer 1 of this embodiment includes the aforementioned printing unit 10. With this configuration, printing can be performed without subjecting the recording paper P to excessive bending.

[0077] Furthermore, the present invention is not limited to the embodiments described above with reference to the accompanying drawings, and various modifications can be considered within its technical scope. For example, in the above embodiments, label release paper is shown as the recording paper P, but the recording paper P can also be a receipt or ticket. Additionally, the recording paper P can also be label release paper without the backing P2.

[0078] Furthermore, without departing from the spirit and scope of the present invention, the constituent elements in the above embodiments can be appropriately replaced with known constituent elements.

Claims

1. A type printing unit, characterized in that, have: Impression rollers, which transport recording paper; A thermal head that presses against the circumferential surface of the impression roller and prints on the recording paper; The paper guide has a guide slope that guides the recording paper toward the printing area of ​​the thermal head, the guide slope becoming an acute angle when the printing area is set as a reference surface; as well as The motor that rotates the impression roller The motor has a circumferential surface that guides the recording paper. The angle between the guide ramp and the reference plane is greater than the angle between the tangent line drawn from the printing area to the circumferential surface of the motor and the reference plane.

2. The printing unit according to claim 1, characterized in that, The paper guide is inserted into the recording paper at an acute angle of less than 57.5° toward the printing area.

3. The printing unit according to claim 1, characterized in that, The paper guide portion has a guide slope with an opening. The printing unit includes: a sensor disposed at the opening and detecting the recording paper; and A sensor holder that can be detachably engaged with the opening and tilted along the guide ramp to hold the sensor.

4. The printing unit according to claim 3, characterized in that, The sensor is mounted on a flexible printed circuit board. The sensor holder has a first beveled portion and a second beveled portion, which indirectly hold the sensor via the flexible printed circuit board by holding the flexible printed circuit board on both sides of the sensor.

5. The printing unit according to claim 4, characterized in that, In either the first inclined portion or the second inclined portion, a recess is formed that is recessed relative to the inner wall surface of the opening, corresponding to the thickness of the flexible printed circuit board.

6. The printing unit according to claim 4, characterized in that, The sensor holder has a locking portion in the space on the back side of the sensor between the first and second inclined portions, which can be detachably engaged with respect to the opening.

7. The printing unit according to claim 1, characterized in that, The recording paper has multiple peelable labels.

8. A thermal printer, characterized in that, It has the printing unit as described in claim 1.

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