CN114103476A - Printing unit and thermal printer - Google Patents

Abstract

The printing unit includes: a platen roller that conveys a recording sheet; a thermal head which is pressed against the circumferential surface of the platen roller and prints on the recording paper (P); and a paper guide portion for inserting the recording paper (P) from an acute angle direction toward a printing area by the thermal head.

Description

Printing unit and thermal printer

Technical Field

The invention relates to a printing unit and a thermal printer.

Background

In a printing unit of a conventionally known thermal printer, a platen roller is rotated in a state where a recording sheet is sandwiched between the platen roller and a thermal head, and a printing surface of the recording sheet is heated by a heating element of the thermal head while the recording sheet is fed, so that the printing surface is developed and printed.

In the above-described conventional printing unit, the recording paper is guided by a substantially rectangular parallelepiped support portion on the front side of the thermal head, and the recording paper is inserted into the printing region of the thermal head while changing its direction by 90 °. Therefore, a strong bending is applied to the recording paper, and peeling of the label may occur under a specific temperature condition (for example, 5 ℃ or less at which the adhesiveness of the label is reduced), for example, in the case of using a die-cut label paper.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a printing unit and a thermal printer that can perform printing without strongly bending a recording sheet.

Disclosure of Invention

A printing unit according to an aspect of the present invention includes: a platen roller that conveys a recording sheet; a thermal head which is pressed against the circumferential surface of the platen roller and prints on the recording paper; and a paper guide portion for inserting the recording paper from an acute angle direction toward a printing region by the thermal head.

In the printing unit according to one aspect of the present invention, the paper guide portion inserts the recording paper from an acute angle direction of 57.5 ° or less toward the printing region.

In the printing unit according to one aspect of the present invention, the motor is provided with a circumferential surface for guiding the recording paper, and the paper guide portion inserts the recording paper toward the printing region from an acute angle direction of an angle equal to or greater than a tangent line drawn from the printing region to the circumferential surface of the motor.

In a printing unit according to an aspect of the present invention, the paper guide has a guide slope on which an opening is formed, and the printing unit includes: a sensor which is disposed in the opening and detects the recording paper; and a sensor holder detachably engaged with the opening and holding the sensor in an inclined manner along the guide slope.

In the printing unit according to one aspect of the present invention, the sensor is provided on a flexible printed circuit board, and the sensor holder includes a first inclined surface portion and a second inclined surface portion that hold the flexible printed circuit board on both sides of the sensor and indirectly hold the sensor via the flexible printed circuit board.

In the printing unit according to one aspect of the present invention, a concave portion that is recessed in accordance with the thickness of the flexible printing substrate with respect to the inner wall surface of the opening portion is formed in either one of the first inclined surface portion and the second inclined surface portion.

In the printing unit according to one aspect of the present invention, the sensor holder includes an engaging portion that is detachably engaged with the opening in a space on the back surface side of the sensor between the first inclined surface portion and the second inclined surface portion.

In the printing unit according to one aspect of the present invention, the recording paper has a plurality of labels that can be peeled off.

A thermal printer according to an aspect of the present invention includes the printing unit described above.

Drawings

Fig. 1 is a perspective view of a thermal printer according to an embodiment.

Fig. 2 is a plan view of a recording sheet according to an embodiment.

Fig. 3 is a front perspective view of a printing unit according to an embodiment.

Fig. 4 is a front exploded perspective view of a printing unit according to an embodiment.

Fig. 5 is a rear perspective view of the printing unit according to the embodiment.

Fig. 6 is a front view of a printing unit according to an embodiment.

Fig. 7 is a view VII-VII in section as shown in fig. 6.

Fig. 8 is a front side exploded perspective view of the electronic component relationship of the printing unit according to the embodiment.

Fig. 9 is a front perspective view of a sensor holder according to an embodiment.

Fig. 10 is a front view of a sensor holder according to an embodiment.

Fig. 11 is a plan view of a sensor holder according to an embodiment.

Fig. 12 is a bottom view of the sensor holder according to the embodiment.

Fig. 13 is a left side view of a sensor holder according to an embodiment.

Fig. 14 is a right side view of a sensor holder according to an embodiment.

Detailed Description

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

Fig. 1 is a perspective view of a thermal printer 1 according to an embodiment. As shown in fig. 1, the thermal printer 1 is configured to be capable of printing a recording sheet P. The recording paper P is a heat-sensitive paper that develops color when heat is applied, and is suitably used for printing various labels, receipts, tickets, and the like. The recording paper P is set in the thermal printer 1 in a state of a roll paper R (wound so as to have a hollow hole), and printing is performed on a portion pulled out from the roll paper R.

The thermal printer frame 1 includes a casing 3, a display section 4, a control section 5, and a printing unit 10. The housing 3 is formed in a hollow box shape by using a plastic or metal material such as ABS (acrylonitrile-styrene-butadiene copolymer) or a composite material of ABS and polycarbonate. The case 3 has a rectangular parallelepiped body portion 6 and a roll paper storage portion 7, and the roll paper storage portion 7 protrudes to one side in the thickness direction of the body portion 6 at one end in the longitudinal direction of the body portion 6.

A printing unit 10 is accommodated at one end of the body 6 in the longitudinal direction. Further, a discharge port 3a is formed in an end face of one end portion in the longitudinal direction of the body portion 6. The discharge port 3a discharges the recording paper P printed by the printing unit 10. The display portion 4 is disposed on the principal surface of the main body portion 6 on the opposite side to the roll paper storage portion 7 in the thickness direction. The display unit 4 is, for example, a liquid crystal panel, is connected to the control unit 5, and displays various information. The roll paper R is stored in the roll paper storage 7.

Fig. 2 is a plan view of a recording sheet P according to an embodiment. As shown in fig. 2, the recording paper P has a plurality of labels P1 that can be peeled off. The label P1 is a rectangular part die-cut from a heat-sensitive layer P3 (base paper) bonded to the side opposite to the printed surface of the recording paper P, and a plurality of labels are formed at intervals in the longitudinal direction of the recording paper P. A frame-like liner (liner) P2 is formed around label P1. Label P1 was peeled from release paper P3 leaving liner P2. As described above, the recording paper P of the present embodiment is label-releasing paper having the liner P2.

Fig. 3 is a front perspective view of the printing unit 10 according to the embodiment. Fig. 4 is a front exploded perspective view of the printing unit 10 according to the embodiment. Fig. 5 is a rear perspective view of the printing unit 10 according to the embodiment. As shown in fig. 3, the printing unit 10 includes: a platen roller 51 having a driven gear 56; a motor 61 that rotates the platen roller 51; a main body frame 11 that rotatably supports the platen roller 51 and assembles the motor 61; a first reduction gear 65 and a second reduction gear 66 that reduce and transmit the driving force of the motor 61 to the driven gear 56; and a thermal head 41 that is pressed against the circumferential surface of the platen roller 51.

The printing unit 10 discharges the recording paper P passing between the platen roller 51 and the thermal head 41 toward the direction indicated by the arrow a. Hereinafter, mainly in the description of the printing unit 10, the direction along the arrow a is defined as the vertical direction L1. A direction perpendicular to the vertical direction L1 and in the axial direction in which the rotation axis of the platen roller 51 extends is defined as a horizontal direction L2. Further, a direction orthogonal to the vertical direction L1 and the horizontal direction L2 is defined as a front-rear direction L3.

In the vertical direction L1, the side on which the recording paper P is discharged (the side indicated by the arrow a) is defined as the top, and the opposite side is defined as the bottom. In the left-right direction L2, the side on which the motor 61 is disposed is defined as the right, and the opposite side is defined as the left. In the front-rear direction L3, the side on which the platen roller 51 is disposed is defined as front, and the opposite side on which the thermal head 41 is disposed is defined as rear.

The main body frame 11 is formed of a plate material such as a polycarbonate resin containing glass fibers. The main body frame 11 is formed in a U shape that is open to the front as viewed from the vertical direction L1. Specifically, the main body frame 11 includes: a back plate portion 12 extending in the left-right direction L2; a first side wall portion 13 that is erected forward from one (left) end portion of the back plate portion 12 in the left-right direction L2; a second side wall portion 14 that is erected forward and downward from the end of the other side (right side) in the left-right direction L2 of the back plate portion 12; and a paper guide 20 provided between the first side wall portion 13 and the second side wall portion 14.

The back plate portion 12 is formed in a plate shape having a thickness in the front-rear direction L3. The first side wall portion 13 is formed in a plate shape having a thickness in the left-right direction L2. A first roller insertion groove 16A cut downward is formed in the upper end edge of the first side wall portion 13. The second side wall portion 14 is formed in a plate shape having a thickness in the left-right direction L2. A second roller insertion groove 16B cut downward is formed in the upper end edge of the second side wall portion 14.

The second roller insertion groove 16B is formed so that the shape and the formation position thereof when viewed in the left-right direction L2 coincide with the first roller insertion groove 16A. The platen roller 51 is detachably inserted into the first roller insertion groove 16A and the second roller insertion groove 16B. The second side wall portion 14 extends forward from the other (right) end portion of the back plate portion 12 in the left-right direction L2, and further extends downward.

The motor 61 is attached to the second side wall portion 14 below the connection portion between the second side wall portion 14 and the back plate portion 12. The motor 61 is attached to the second side wall portion 14 from the inside in the left-right direction L2, and the output shaft 61A of the motor 61 penetrates the second side wall portion 14 and protrudes outward in the left-right direction L2 of the second side wall portion 14. The motor 61 is connected to the control unit 5 (see fig. 1) via a flexible printed circuit board 71 on which a wiring pattern (not shown) is printed and wired. The motor 61 is driven based on a signal from the control section 5.

A gear box portion 17 is formed outside the second side wall portion 14. The gear box portion 17 has a peripheral wall portion 18 that is erected outward in the left-right direction L2 from the peripheral edge of the second side wall portion 14. The peripheral wall portion 18 is formed in a U shape that is open upward when viewed in the left-right direction L2. The gear box portion 17 opens outward in the left-right direction L2.

A recess 19 recessed downward is formed in each of the front upper end edge and the rear upper end edge of the peripheral wall 18. The pair of concave portions 19 are formed so as to match each other in shape and position when viewed in the front-rear direction L3. Further, a hole 18a is formed in a lower portion of the peripheral wall 18. A cover member, not shown, covering the gear box portion 17 is engaged with the pair of concave portions 19 and the hole portion 18 a.

A first reduction gear 65 and a second reduction gear 66 are assembled inside the gear box portion 17. As shown in fig. 4, the first reduction gear 65 is rotatably supported by a first rotation shaft 67 that is erected from the second side wall 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 rotation shaft 67 by a second rotation shaft 68 standing from the second side wall portion 14. The second reduction gear 66 meshes with the first reduction gear 65.

The paper guide 20 is formed in a substantially right-angled triangular column shape extending in the left-right direction L2. With regard to the paper guide 20, an end portion on one side (left side) in the left-right direction L2 is connected to an inner side surface of the first side wall portion 13, and an end portion on the other side (right side) in the left-right direction L2 is connected to an inner side surface of the second side wall portion 14. The paper guide 20 is formed with a pair of mounting portions 20a recessed downward as viewed from the front-rear direction L3.

The pair of attachment portions 20a are formed with an interval in the left-right direction L2. A through hole 20b penetrating the bottom of the mounting portion 20a in the vertical direction is provided in the bottom of the mounting portion 20 a. The main body frame 11 is mounted to the housing 3 (see fig. 1) by inserting a fastening member such as a bolt through the through hole 20b of the paper guide 20.

The thermal head 41 prints on the recording paper P (see fig. 3). The thermal head 41 is formed in a rectangular shape having a longitudinal direction L2 as viewed from the front-rear direction L3. The thermal head 41 is disposed in a state where the longitudinal direction thereof coincides with the width direction of the recording paper P. On the head surface 41a of the thermal head 41, a plurality of heat generating elements 42 are arranged in the left-right direction L2.

The head surface 41a faces the printing surface of the recording paper P, and can nip the recording paper P between the outer circumferential surface of the platen roller 51. The thermal head 41 is connected to the control unit 5 (see fig. 1) via the flexible printed board 71, and a driver (ドライバ — IC) (not shown) mounted on the thermal head 41 controls heat generation of the heating element 42 based on a signal from the control unit 5. The thermal head 41 controls heat generation of the heating element 42 to print various characters, graphics, and the like on the printing surface of the recording paper P.

The thermal head 41 is adhesively fixed to a head support 45 supported by the main body frame 11. The head support 45 is a plate-like member having a longitudinal direction L2 in the lateral direction, and the thermal head 41 is fixed to the front surface thereof. The head support 45 is disposed between the first side wall 13 and the second side wall 14, and between the back plate 12 and the paper guide 20 (see fig. 7 described later).

As shown in fig. 5, an elastic member 46 biased in a direction to separate the head support 45 and the back plate portion 12 from each other is interposed between the head support 45 and the back plate portion 12. That is, the elastic member 46 is configured to always press the head support 45 forward. A plurality of (three in the present embodiment) elastic members 46 are arranged at intervals in the left-right direction L2.

As shown in fig. 4, a pair of stoppers 45a for limiting the range of rotation of the head support 45 are formed at the upper end portion of the head support 45. The pair of stoppers 45a are formed in a substantially quadrangular prism shape and extend outward in the left-right direction L2 of the head support 45. The pair of stoppers 45a are inserted into the rectangular hole 13a formed in the upper portion of the first side wall 13 and the rectangular hole 14a formed in the upper portion of the second side wall 14 of the main body frame 11. The stopper 45a moves in the holes 13a, 14a in accordance with the rotation of the head support 45, and is configured to be able to contact the inner wall surfaces of the holes 13a, 14 a. The stopper 45a contacts the inner wall surfaces of the hole portions 13a, 14a, thereby limiting the amount of rotation of the head support 45.

As shown in fig. 3, the platen roller 51 is disposed to face the thermal head 41, rotates with the recording paper P interposed between the thermal head 41, and feeds out the recording paper P in the direction indicated by the arrow a. The platen roller 51 includes a roller shaft 52, a roller body 53 externally fitted to the roller shaft 52, and a pair of bearings 54 attached to both ends of the roller shaft 52. The roller shaft 52 is formed slightly longer than the separation distance between the first side wall portion 13 and the second side wall portion 14 of the main body frame 11. The roller main body 53 is formed of, for example, rubber, and is uniformly arranged along the left-right direction L2 over the entire roller shaft 52 except for both ends thereof.

With respect to the platen roller 51, a pair of bearings 54 fitted to both ends are inserted into the first roller insertion groove 16A and the second roller insertion groove 16B of the main body frame 11. Thereby, the platen roller 51 is rotatably and detachably held by the main body frame 11. In a state where the platen roller 51 is inserted into the first roller insertion groove 16A and the second roller insertion groove 16B, the roller main body 53 is provided in contact with the thermal head 41 so as to sandwich the recording paper P drawn out from the roll paper R (see fig. 1).

As shown in fig. 3, a driven gear 56 is fixed to the other (right) end of the platen roller 51 in the left-right direction L2. The driven gear 56 is assembled to the upper portion of the gear box portion 17 while the platen roller 51 is held by the first side wall portion 13 and the second side wall portion 14. At this time, the driven gear 56 overlaps the second reduction gear 66 as viewed in the left-right direction L2, is disposed further inward than the second reduction gear 66, and meshes with the second reduction gear 66. Thereby, 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 platen roller 51 is rotatable while being held by the first side wall 13 and the second side wall 14, and feeds out the recording paper P (see fig. 2).

Fig. 6 is a front view of the printing unit 10 according to the embodiment. Fig. 7 is a view VII-VII in section as shown in fig. 6. Fig. 8 is a front side exploded perspective view of the electronic component relationship of the printing unit 10 according to the embodiment. As shown in fig. 7, the paper guide 20 has a guide slope 21 for inserting the recording paper P from an acute angle direction toward the printing area 100 by the thermal head 41.

Here, the printing region 100 is a region facing the platen roller 51 and is a head surface 41a of the thermal head 41 on which the heat generating element 42 is provided. The print region 100 is a region pressed against the circumferential surface of the platen roller 51 in a narrow sense in the head surface 41 a. The print region 100 of the present embodiment is a planar region extending in the vertical direction L1 and the horizontal direction L2.

The guide slope 21 is inclined at an angle θ 1 with respect to the printing region 100. When the print region 100 is set to 0 ° of the reference plane, the angle θ 1 is an acute angle smaller than 90 °. The angle θ 1 may be an acute angle of 57.5 ° or less. This prevents the mark P1 (see fig. 2) from being peeled off without strongly bending the recording paper P, and allows the recording paper P to be inserted into the printing region 100. That is, the upper limit of the angle θ 1 may be 57.5 °.

On the other hand, the lower limit of the angle θ 1 may be the angle θ 2. The angle θ 2 is an angle formed by a tangent 101 drawn from the printing region 100 to the circumferential surface 61a of the motor 61 with respect to the printing region 100. As shown in fig. 3, the circumferential surface 61a of the motor 61 is disposed in the paper passage path of the recording paper P and guides the recording paper P. When the angle θ 1 is smaller than the angle θ 2, the recording paper P floats on the guide slope 21, which is not preferable. That is, the guide slope 21 may be inclined at an angle equal to or larger than the angle θ 2 with respect to the printing region 100.

The guide slope 21 of the present embodiment is inclined at an acute angle of 37.5 ° with respect to the printing region 100. The guide slope 21 is set to 37.5 °, so that a minimum internal space required for disposing the sensor 81 described later on the guide slope 21 can be secured in the paper guide 20. Thus, the angle θ 1 may be equal to or larger than the angle θ 2 and equal to or smaller than 57.5 °, and more preferably equal to or larger than 37.5 ° and equal to or smaller than 57.5 °.

As shown in fig. 6, an opening 22 for disposing the sensor 81 is formed in the guide slope 21. The opening 22 is formed in a T shape in front view. The opening 22 is disposed between the pair of mounting portions 20a in the left-right direction of the guide slope 21. The opening 22 is disposed between the pair of mounting portions 20a and near the mounting portion 20a on one side (left side) in the left-right direction.

A sensor 81 for detecting the recording paper P is disposed in the opening 22. The sensor 81 of the present embodiment is a light reflector. The sensor 81 may be a non-contact sensor other than a light reflector. The sensor 81 may be a contact sensor. As shown in fig. 8, the sensor 81 is provided on the flexible printed substrate 71.

The flexible printed circuit 71 includes: a head connecting portion 72 connected to the heating element 42, a motor connecting portion 73 connected to the motor 61, and a sensor connecting portion 74 connected to the sensor 81. The sensor connecting portion 74 and the sensor 81 are inserted together with the sensor holder 91 from the bottom surface side of the paper guide 20 with respect to the opening 22 of the paper guide 20. The sensor holder 91 is a resin molded component and detachably engaged with the opening 22 of the paper guide 20.

Fig. 9 is a front perspective view of a sensor holder 91 according to an embodiment. Fig. 10 is a front view of a sensor holder 91 according to an embodiment. Fig. 11 is a plan view of a sensor holder 91 according to an embodiment. Fig. 12 is a bottom view of a sensor holder 91 according to an embodiment. Fig. 13 is a left side view of a sensor holder 91 according to an embodiment. Fig. 14 is a right side view of a sensor holder 91 according to an embodiment. As shown in fig. 9, the sensor holder 91 includes a base portion 92, a first inclined surface portion 93A, a second inclined surface portion 93B, and an engagement portion 94.

As shown in fig. 9 and 10, the base portion 92 is formed in a plate shape having a thickness in the vertical direction L1. As shown in fig. 11, the base portion 92 connects inner side surfaces in the left-right direction L2 of the first and second inclined surface portions 93A and 93B to each other. A rib 92a that improves the bending rigidity of the base 92 stands on the upper surface of the base 92. The rib 92a also extends in the left-right direction L2, and connects the inner side surfaces of the first inclined surface portion 93A and the second inclined surface portion 93B in the left-right direction L2.

The first inclined surface portion 93A is formed in a substantially right-angled triangular shape in a left side view shown in fig. 13. The second inclined surface portion 93B is also formed in a substantially right triangular shape in a right side view shown in fig. 14. The first and second slope parts 93A and 93B are inclined at the same angle. Further, as shown in fig. 12, a thinned portion 97 at the time of resin molding is formed on the bottom surfaces of the first inclined surface portion 93A and the second inclined surface portion 93B. As shown in fig. 9, the first inclined surface portion 93A and the second inclined surface portion 93B are arranged in the left-right direction L2 with a space therebetween. The space has a size in the left-right direction L2 in which the sensor 81 can be disposed.

The first and second slope parts 93A and 93B hold the sensor connection parts 74 on both sides of the sensor 81 in the flexible printed board 71, thereby indirectly holding the sensor 81 via the flexible printed board 71. As shown in fig. 8, in the paper guide 20, a pair of nip portions 23 for sandwiching the flexible printed board 71 (sensor connection portion 74) is formed between the first inclined surface portion 93A and the second inclined surface portion 93B. The pair of nip portions 23 extend from the upper end opening edge of the opening 22 of the paper guide portion 20 toward the inside of the opening 22.

A pair of cutout portions 74b are formed at upper end portions of both sides of the sensor attachment portion 74 in the left-right direction L2. A pair of shoulders 95 that descend from the top of the sensor holder 91 by one step are formed at positions corresponding to the pair of cutout portions 74B in the first and second inclined surface portions 93A and 93B. The pair of shoulders 95 are disposed on the back side of the guide slope 21, and the upper surfaces thereof abut against the top surface of the inside of the paper guide 20, thereby positioning the sensor holder 91 in the vertical direction L1.

The engaging portion 94 is detachably engaged with the engaged portion 24 formed on the inner wall surface of the rear side of the opening 22. As shown in fig. 9 and 11, the engaging portion 94 is disposed between the first inclined surface portion 93A and the second inclined surface portion 93B in the left-right direction L2, and is provided continuously with the rear side of the base portion 92. The engaging portion 94 extends rearward from the base portion 92 and is bent upward, and has a projection (hook) projecting rearward at an upper end thereof. The engaging portion 94 is elastically deformable in the front and rear direction in a space between the first inclined surface portion 93A and the second inclined surface portion 93B.

As shown in fig. 7, the engaging portion 94 is engaged with the engaged portion 24. Thereby, the sensor holder 91 is assembled to the paper guide 20. The sensor holder 91 has a recess 96 recessed corresponding to the thickness of the flexible printed board 71 with respect to the inner wall surface 22a on the front side of the opening 22. As shown in fig. 9, a concave portion 96 is formed at the front lower end portion of the second slope surface portion 93B. The recessed portion 96 is provided with a band-shaped portion 74a of the sensor connecting portion 74 shown in fig. 8. This makes it possible to prevent the wiring pattern formed on the band-shaped portion 74a from being damaged by being sandwiched between the sensor holder 91 and the inner wall surface 22a of the opening 22.

As described above, the printing unit 10 of the present embodiment includes: a platen roller 51 that conveys the recording sheet P; a thermal head 41 that is pressed against the circumferential surface of the platen roller 51 and prints on the recording paper P; and a paper guide 20 for inserting the recording paper P from an acute angle direction toward the printing area 100 by the thermal head 41. This allows the recording paper P to be inserted into the printing region 100 without bending the recording paper P strongly. Therefore, the label P1 of the recording paper P can be prevented from being peeled off. Further, the paper guide 20 is finer than the conventional quadrangular prism-shaped paper guide, and therefore, can contribute to downsizing and space saving of the apparatus.

In the present embodiment, as shown in fig. 7, the paper guide 20 inserts the recording paper P from an acute angle direction of 57.5 ° or less toward the printing region 100. According to this configuration, the label P1 of the recording paper P can be prevented from being peeled off even under a specific temperature condition (for example, 5 ℃ or less at which the label adhesiveness is lowered).

In the present embodiment, a motor 61 for rotating the platen roller 51 is provided, the motor 61 has a circumferential surface 61a for guiding the recording paper P, and the paper guide 20 inserts the recording paper P toward the printing region 100 from an acute angle direction of an angle θ 1 equal to or larger than a tangent 101 drawn from the printing region 100 to the circumferential surface 61a of the motor 61. According to this configuration, the recording paper P is prevented from floating, and wrinkles and the like do not occur in the printed recording paper P.

In the present embodiment, the paper guide 20 has a guide slope 21 in which an opening 22 is formed, and includes: a sensor 81 disposed in the opening 22 and detecting the recording paper P; and a sensor holder 91 detachably engaged with the opening 22 and holding the sensor 81 obliquely along the guide slope 21. According to this configuration, the sensor 81 can be easily disposed along the guide slope 21 inclined with respect to the printing region 100.

In addition, in the present embodiment, as shown in fig. 8, the sensor 81 is provided on the flexible printed board 71, the sensor holder 91 has the first and second slope parts 93A and 93B, and the first and second slope parts 93A and 93B hold the flexible printed board 71 on both sides of the sensor 81 to indirectly hold the sensor 81 via the flexible printed board 71. According to this configuration, the sensor holder 91 can prevent the sensor 81 from being held in an inclined state due to the influence of the irregularities of the terminals of the sensor 81.

In the present embodiment, as shown in fig. 7, a recess 96 is formed in either one of the first inclined surface portion 93A and the second inclined surface portion 93B (the second inclined surface portion 93B in the present embodiment) so as to be recessed in accordance with the thickness of the flexible printed board 71 with respect to the inner wall surface 22a of the opening 22. According to this configuration, the band-shaped portion 74a of the flexible printed circuit 71 inserted into the opening 22 together with the sensor holder 91 can be prevented from being damaged.

In the present embodiment, the sensor holder 91 has an engagement portion 94 that is detachably engaged with the opening 22 in a space S on the back side of the sensor 81 between the first inclined surface portion 93A and the second inclined surface portion 93B. According to this configuration, the engaging portion 94 can be elastically deformed in the front-rear direction by the space S on the rear surface side of the sensor 81 between the first inclined surface portion 93A and the second inclined surface portion 93B, so that the sensor holder 91 can be easily attached to and detached from the opening 22,

in the present embodiment, as shown in fig. 2, the recording paper P has a plurality of peelable labels P1. With this configuration, the label P1 can be prevented from being peeled off from the paper path of the recording paper P.

The thermal printer 1 of the present embodiment includes the printing unit 10. According to this configuration, printing can be performed without applying strong bending to the recording paper P.

The present invention is not limited to the above-described embodiments described with reference to the drawings, and various modifications are conceivable within the technical scope thereof. For example, in the above embodiment, the label release paper is shown as an example of the recording paper P, but the recording paper P may be a receipt or a ticket. The recording paper P may be label-releasing paper without the liner P2.

In addition, the components in the above-described embodiments may be replaced with known components as appropriate without departing from the scope of the present invention.

Claims (9)

1. A printing unit is characterized by comprising:

a platen roller that conveys a recording sheet;

a thermal head that is pressed against the circumferential surface of the platen roller and prints on the recording paper; and

and a paper guide portion for inserting the recording paper from an acute angle direction toward a printing region by the thermal head.

2. The printing unit according to claim 1, wherein the paper guide portion inserts the recording paper from an acute angle direction of 57.5 ° or less toward the printing region.

3. The printing unit according to claim 1,

a motor for rotating the platen roller is provided,

the motor has a circumferential surface that guides the recording paper,

the paper guide portion inserts the recording paper in an acute angle direction of an angle from the printing area to a tangent line of a circumferential surface of the motor or more.

4. The printing unit according to claim 1,

the paper guide portion has a guide slope formed with an opening portion,

the printing unit includes: a sensor which is disposed in the opening and detects the recording paper; and

and a sensor holder detachably engaged with the opening and holding the sensor obliquely along the guide slope.

5. The printing unit according to claim 4,

the sensor is arranged on the flexible printed substrate,

the sensor holder has a first slope part and a second slope part that hold the flexible printed substrate on both sides of the sensor to indirectly hold the sensor via the flexible printed substrate.

6. The printing unit according to claim 5, wherein a recess recessed in accordance with the thickness of the flexible printed board with respect to the inner wall surface of the opening is formed in either one of the first inclined surface portion and the second inclined surface portion.

7. The printing unit according to claim 5, wherein the sensor holder has an engaging portion that is detachably engaged with the opening in a space on the back surface side of the sensor between the first inclined surface portion and the second inclined surface portion.

8. The printing unit according to claim 1, wherein the recording paper has a plurality of labels that can be peeled off.

9. A thermal printer comprising the printing unit according to claim 1.

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