JP5197272B2 - Platen roller positioning mechanism and printer having the same - Google Patents

Description

  The present invention relates to a mechanism for positioning a relative position of a platen roller and a thermal head in a thermal printer, and a printer including the mechanism.

  In thermal printers, thermal paper or an ink sheet is sandwiched between the thermal head and the platen roller, and the color of the thermal paper is changed by the pressure of the thermal head and the platen roller and the heat of the thermal head, or the ink on the ink sheet. Is printed on the photographic paper.

  Here, the thermal head and the platen roller are not fixed to the casing of the printer, and the relative positions of the thermal head and the platen roller are separated when necessary except during printing. Because it does not receive power from, you can move freely.

  At the time of printing, the platen roller needs to be pressure-bonded with a heater line that supplies heat from the thermal head in a relatively correct positional relationship. That is, the rotation axis of the heater line and the platen roller is parallel, and the heater line is required to be in contact with the platen roller at any position. If the positional relationship is not correct, the print image may be faint or other print defects may occur.

  For this reason, for example, Patent Document 1 proposes a printer having a structure that positions the platen roller according to the position of the head when the head is pressure-bonded to the platen roller.

JP 2006-297682 A

  In the above-mentioned Patent Document 1, when the thermal head approaches the platen roller, the platen roller is set at a specific position with respect to the thermal head so that the platen roller is placed at a specific position, and the thermal head is distorted. The relative position of the thermal head and the platen roller is determined by making the platen roller follow the position change. Further, the positional relationship between the thermal head and the platen roller at the time of printing is limited to a specific position set by the mechanism.

  In a thermal printer, it is necessary to radiate the heat generated by the thermal head during printing and control the temperature of the thermal head. Therefore, a heat radiating member integrated with the thermal head is provided to radiate heat constantly. Since the printing time cannot be shortened unless the heat dissipation effect is increased, the size and weight of the heat dissipation member are increased.

  As described above, it is necessary to separate the relative positions of the thermal head and the platen roller. However, a large driving force is required to drive the thermal head and the heavy heat dissipating member attached thereto, and the operation takes time. For this reason, if the thermal head is driven away from the platen roller, the cost increases, which is undesirable from the viewpoint of shortening the printing time.

  Also, the contact position between the thermal head and the platen roller during printing always depends on the environmental temperature in which the printer is installed, the temperature inside the printer, the printing paper and ink sheet used, the pattern of the printed image, the color density, etc. A particular location is not always optimal. Therefore, if the relative positional relationship between the thermal head and the platen roller at the time of printing can be changed as necessary, it is possible to obtain a high quality printing.

  In view of the above problems, an object of the present invention is to provide a platen roller positioning mechanism capable of arbitrarily adjusting a contact position between a platen roller and a thermal head, and a printer including the same.

The platen roller positioning mechanism of the present invention includes a platen roller, a thermal head having a predetermined width in the tangential direction of the platen roller, and the platen roller and the thermal head so that the platen roller and the thermal head are paired to sandwich the printing paper. A relative position change mechanism that changes the relative position of the head, and a contact position adjustment mechanism that arbitrarily adjusts the contact position at the time of pinching between the platen roller and the thermal head in a predetermined width direction . A head base for fixing the thermal head, and a platen unit that supports the platen roller and moves so that the platen roller contacts and separates from the thermal head, and the contact position adjusting mechanism is movable in a predetermined width direction. And a biased platen unit and a rotation about a predetermined axis on the platen unit A lever that is fixed on the platen unit and is in contact with the first end of the lever to determine the rotation posture of the lever; a second end of the lever fixed on the head base; A head base positioning member that abuts on the downstream side of the urging force applied to the platen unit, and the platen unit moves in a predetermined width direction according to the pivoting posture of the lever, so that the contact position of the platen roller and the thermal head is adjusted. adjust.

The platen roller positioning mechanism of the present invention includes a contact position adjusting mechanism that arbitrarily adjusts the contact position during clamping of the platen roller and the thermal head in a predetermined width direction. By arbitrarily adjusting the contact position between the platen roller and the thermal head in accordance with the temperature inside and outside the printer, the photographic paper, the printed image, and the color density, it is possible to perform high-quality printing. The relative position changing mechanism includes a head base that fixes the thermal head, and a platen unit that supports the platen roller and moves so that the platen roller contacts and separates from the thermal head. Since the platen unit and the platen roller are lighter than the head base, the platen roller is positioned by changing the relative position of the platen roller and the thermal head with a smaller driving force than when the thermal head is moved together with the head base. I can do it. The contact position adjusting mechanism includes a platen unit that is movable and biased in a predetermined width direction, a lever that rotates about a predetermined axis on the platen unit, and a fixed first plate of the lever. Rotation posture determining member that contacts the end portion to determine the rotation posture of the lever, and head base positioning that is fixed on the head base and contacts the second end portion of the lever and the downstream side of the urging force applied to the platen unit A platen unit that moves in a predetermined width direction according to the pivoting posture of the lever, thereby adjusting the contact position between the platen roller and the thermal head. Therefore, it is possible to determine the rotation posture of the lever with a small driving force for rotating the rotation posture determination member and change the contact position between the platen roller and the thermal head.

(Embodiment 1)
<Overall configuration>
The platen roller positioning mechanism according to the first embodiment is installed inside the thermal printer to position the platen roller. First, the configuration of the platen roller positioning mechanism in the first embodiment will be described with reference to FIG. FIG. 5 is a configuration diagram of a platen roller positioning mechanism according to the first embodiment. Although not shown in FIG. 5, a housing is provided around the platen roller positioning mechanism to constitute a thermal printer.

  The platen roller positioning mechanism according to the first embodiment includes a platen roller 1, a platen unit 6 that supports the platen roller 1, a thermal head 9, and a head base 10 that fixes the thermal head 9.

  The platen roller 1 is supported by the platen unit 6 and is rotatably installed. The platen unit 6 is fitted with a shaft 12 fitted with a guide (not shown) provided in the printer housing, and can rotate in the c and d directions shown in FIG. I can do it. Thereby, the platen unit 6 and the shaft 12 have a function as a relative position changing mechanism that changes the relative position of the platen roller 1 and the thermal head 9. Further, the shaft 12 can be moved in the a and b directions shown in FIG. 5 by the guide, and the platen unit 6 can be moved in the a and b directions following this. Thereby, the platen unit 6 and the shaft 12 have a function as a contact position adjusting mechanism for changing the contact position between the platen roller 1 and the thermal head 9. Here, the a and b directions are tangential directions of the platen roller 1 and are substantially parallel to the surface of the thermal head 9. The platen unit 6 is urged in the direction b by a spring 14.

  The thermal head 9 has a predetermined width in the tangential direction of the platen roller 1 and incorporates a heater line (not shown) for applying heat to the photographic paper.

  The head base 10 is fixed to a printer casing (not shown) or the like, and a thermal head 9 is fixed to the top thereof. The head base 10 has a function as a heat radiating plate for radiating heat from the thermal head 9 and is heavier than the platen roller 1 and the platen unit 6. That is, the relative position of the head base 10 and the thermal head 9 does not change.

  Further, as a contact position changing mechanism for changing the contact position between the platen roller 1 and the thermal head 9, the platen roller positioning mechanism according to the first embodiment includes a lever 2, a positioning member 5, and a head base positioning member in addition to the platen unit 6. 10a.

  The lever 2 rotates about the rotation axis of the platen roller 1. The turning posture of the lever 2 is determined by the positioning member 5 and the head base positioning member 10a. The positioning member 5 is installed on the platen unit 6 and comes into contact with the contact portion 2 a of the lever 2. A bearing 4 is provided at the other end of the lever 2 and comes into contact with a head base positioning member 10 a fixed on the head base 10. The lever 2 is given a biasing force by a spring 15 in a direction in which the contact portion 2 a comes into contact with the positioning member 5.

  As shown in FIG. 5, the platen roller 1 is positioned above the thermal head 9. That is, in the thermal printer of the first embodiment, the platen roller 1 is located above the thermal head 9. Thereby, the head base 10 for fixing the thermal head 9 can be installed below the printer, and the stability can be improved by lowering the center of gravity of the printer. Furthermore, compared with the case where the platen roller 1 moves upward and performs pressure bonding, the pressure can be stably bonded to the thermal head 9.

  In other words, the platen roller positioning mechanism according to the first embodiment includes a platen roller 1, a thermal head 9 having a predetermined width in the tangential direction of the platen roller 1, and the platen roller 1 and the thermal head 9 as a pair. The relative position changing mechanism that changes the relative position of the platen roller 1 and the thermal head 9 so as to clamp the pressure, and the contact that arbitrarily adjusts the contact position when the platen roller 1 and the thermal head 9 are clamped in the predetermined width direction. A position adjusting mechanism. As a result, the contact position between the platen roller 1 and the thermal head 9 can be arbitrarily adjusted according to the temperature inside and outside the printer, the photographic paper, the print image, and the color density, and high-quality printing can be performed. .

  Next, each component mounted on the platen unit 6 not shown in FIG. 5 will be described. 3 and 4 are perspective views showing the configuration of the platen unit 6 from different directions. The platen unit 6 is provided with a platen roller 1, a positioning member 5, a motor 7, and a torque limiter 8. The platen roller 1 and the positioning member 5 are rotatable.

  The motor 7 serves as rotational power for the platen roller, and the rotational torque of the motor 7 is transmitted through a gear group installed on the platen unit 6 to a torque limiter 8 installed on the rotation axis of the platen roller 1. It is transmitted to. The rotational torque of the torque limiter 8 is transmitted to the platen roller 1, and the platen roller 1 rotates.

  An elongated hole 6a that penetrates the shaft 12 (not shown, see FIG. 5) is provided at one end of the platen unit 6.

<Configuration of the periphery of lever 2>
Next, the peripheral portion of the lever 2 will be further described with reference to FIG. FIG. 1 shows a state in which the thermal head 9 and the platen roller 1 are pressure-bonded during printing in the first embodiment. Unlike FIG. 5, the platen unit 6 is not shown.

  The lever 2 is rotatably disposed at both ends of the platen roller 1 via bearings 3.

  That is, the predetermined axis that becomes the rotation center of the lever 2 is the rotation axis of the platen roller 1, and the lever 2 is fitted to both ends of the platen roller 1 with the platen roller 1 being rotatable. By installing the lever 2 so that the rotation center of the lever 2 is the rotation axis of the platen roller 1, space saving is achieved compared to the case where the lever 2 and the platen roller 1 are installed independently in the platen unit 6. Can be planned. Furthermore, since the lever 2 is fitted into both ends of the platen roller 1, if the positioning member 5 and the head base positioning member 10 a as the rotation posture determining member are installed at both ends of the platen roller 1 in accordance with the lever 2, The rotation posture of the lever 2 can be set independently. Thereby, even if there is a manufacturing dimensional variation in each of these components, the relative position of the platen roller 1 and the thermal head 9 can be set accurately.

  Next, the shape of the positioning member 5 will be described with reference to FIG. The positioning member 5 has a substantially disk shape, but has a cam shape in which the radius from the center differs depending on the position of the circumference. For example, the radius R5a at the position 5a on the circumference of the positioning member 5 is smaller than the radius R5b at the position 5b. The positioning member 5 is rotated by the driving force of the motor 16 (see FIG. 4) and can take any rotation angle.

  That is, the positioning member 5 as the rotation posture determining member is an eccentric cam capable of controlling the rotation angle. As a result, the turning posture of the lever 2 can be adjusted by the rotational posture of the positioning member 5.

<Relative position change operation>
Next, the operation of the platen roller positioning mechanism of the first embodiment will be described. The relative position of the platen roller 1 and the thermal head 9 changes between printing and non-printing. This relative position changing operation will be described.

  At the time of printing, the printing paper 13 fed from the outside to the thermal printer is inserted between the thermal head 9 and the platen roller 1. Then, the platen roller 1 moves to a position where the platen roller 1 contacts the thermal head 9, and both perform the printing by pinching the printing paper 13.

  Specifically, the platen unit 6 is rotated around the shaft 12 by a driving means (not shown) in the direction d of FIG. 5, and the platen roller 1 is pressure-bonded to the thermal head 9 with a predetermined pressure. At the time of non-printing, the platen unit 1 is moved away from the thermal head 9 by rotating the platen unit 6 in the direction c of FIG.

  That is, the relative position changing mechanism includes a head base 10 that fixes the thermal head 9, and a platen unit 6 that supports the platen roller 1 and moves so that the platen roller 1 contacts and separates from the thermal head 9. Since the platen unit 6 and the platen roller 1 are lighter than the head base 10, the relative position of the platen roller 1 and the thermal head 9 is changed with a smaller driving force than when the thermal head 9 is moved together with the head base 10. The platen roller 1 can be positioned.

  More specifically, the platen unit 6 includes a shaft 12 installed in parallel with the platen roller 1, and the platen unit 6 rotates around the shaft 12 to change the relative position between the platen roller 1 and the thermal head 9. Change. As will be described in detail later, when the shaft 12 moves in the predetermined width direction (directions a and b in FIG. 5), the platen unit 6 moves in the predetermined width direction. When the platen unit 6 rotates, the platen roller 1 is pressed against or separated from the thermal head 9, and the platen unit 6 moves in a predetermined width direction of the thermal head 9 according to the shaft 12, whereby the platen roller 1 and the thermal head are moved. 9 contact positions can be adjusted.

<Head base positioning member 10a>
Next, the positional relationship between the bearing 4 and the head base positioning member 10a during printing will be described with reference to FIG. At the time of printing, the motor 7 (see FIG. 3) rotates, and the rotational torque of the motor 7 is applied to the platen roller 1 through the torque limiter 8, and the platen roller 1 rotates in the direction c in FIG. Since the platen roller 1 and the thermal head 9 sandwich the photographic paper 13 during printing, a frictional force is generated between the platen roller 1 and the photographic paper 13, and the photographic paper 13 is driven in the a direction by this frictional force. And move in direction a.

  At the same time as the driving force is applied from the platen roller 1, the photographic paper 13 is also applied in the direction a from a grip roller (not shown). The photographic paper 13 moves in the direction a by the driving force applied from both the platen roller 1 and the grip roller. Since the platen roller 1 applies a driving force in the direction a to the photographic paper 13, the platen roller 1 itself receives the reaction force, and has the same magnitude as the force applied to the photographic paper 13 in the b direction opposite to the a direction. Receive the power of

  Since the platen roller 1 is supported by the platen unit 6, the platen unit 6 receives a force in the b direction from the platen roller 1. In addition, the platen unit 6 receives a biasing force from the spring 14 in the b direction. Since the platen unit 6 can move in the a direction and the b direction as described above, it moves in the b direction by the force from the platen roller 1 and the biasing force of the spring 14. However, when the bearing 4 installed at one end of the lever 2 contacts the head base positioning member 10a on the head base 10, the movement is prevented.

  The lever 2 rotates about the platen roller 1 as a rotation axis, and a bearing 3 is incorporated at the center of rotation. Therefore, even if the pressing reaction force from the head base positioning member 10a is applied to the lever 2 by the bearing 4 coming into contact with the head base positioning member 10a, the degree of freedom of the rotational movement of the platen roller 1 is not hindered.

  Further, since the bearing 4 provided at the portion where the lever 2 abuts against the head base positioning member 10a is rotatable, the degree of freedom of the rotational movement around the shaft 12 of the platen unit 6 is not hindered.

  In other words, the relative position changing mechanism includes the bearing 4 in a portion in contact with the head base positioning member 10a as the second end of the lever 2. Thereby, since the bearing 4 is rotatable, even if the lever 2 is in contact with the head base positioning member 10a, the degree of freedom of the rotational movement of the platen unit 6 around the shaft 12 is not hindered.

  When the printing is finished, the driving means (not shown) rotates the platen unit 6 in the direction c to separate the thermal head 9 and the platen roller 1 from each other. At this time, since the platen unit 6 is urged in the direction b by the spring 14, the lever 2 is in contact with the head base positioning member 10 a, but the bearing 4 is in contact with the lever 2. Since it is provided, the rotational movement of the platen unit 6 in the c direction is not hindered. When the platen unit 6 further rotates in the c direction, the bearing 4 and the head base positioning portion 10a are separated from each other. However, in this state, the platen unit 6 is fixed by a latch mechanism (not shown) so as not to move in the direction b by the urging force of the spring 14. That is, the latch mechanism fixes the movement of the platen unit 6 in the b direction at the rotation angle of the platen unit 6 such that the bearing 4 provided at the end of the lever 2 does not contact the head base positioning portion 10a. . However, the movement of the platen unit 6 in the b direction is not hindered at the rotation angle of the platen unit 6 such that the bearing 4 contacts the head base positioning portion 10a. Thereby, the contact position adjustment operation of the thermal head 9 and the platen roller 1 described later according to the rotation posture control of the positioning member 5 becomes possible.

  Even when the thermal head 9 and the platen roller 1 move from the separated state to the pressure-bonded state, the bearing 4 abuts on the head base positioning member 10a, but the platen unit 6 rotates in the d direction due to the rotation of the bearing 4. Exercise is not inhibited.

  As described above, in the positional relationship where the platen roller 1 contacts the thermal head 9, the bearing 4 contacts the head base positioning member 10a.

<Contact position adjustment operation>
Next, a contact position adjustment operation for adjusting the contact position between the thermal head 9 and the platen roller 1 will be described. In the first embodiment, when the thermal head 9 and the platen roller 1 are in contact with each other, the contact position is adjusted in the tangential direction of the platen roller 1 and in the direction parallel to the surface of the thermal head 9. FIG. 6 shows the positional relationship between the lever 2, the positioning member 5, and the head base 10.

  6, when the bearing 4 formed at one end of the lever 2 is pressed against the head base positioning member 10a of the head base 10, the lever 2 is applied with a force in the direction e shown in FIG. Furthermore, the lever 2 is also applied with a force in the direction e by the biasing force of the spring 15 (see FIG. 5). However, the lever 2 cannot freely rotate, and stops rotating at the position where the contact portion 2a of the lever 2 contacts the positioning member 5, and the posture of the rotation position (rotation posture) is determined. The positioning member 5 receives a force from the contact portion 2a of the lever 2, but does not rotate by the force.

  That is, the contact position adjusting mechanism includes a spring that applies a biasing force to the lever 2 so that the contact portion 2a as the first end portion abuts on the positioning member 5 as the rotation posture determining member. Thereby, the contact part 2a of the lever 2 is made to contact | abut to the positioning member 5, and the rotation attitude | position of the lever 2 can be determined.

  FIG. 7 is a view showing the positional relationship among the lever 2, the positioning member 5, and the head base 10 as in FIG. 6. The lever 2 shown in FIG. 6 rotates in the e direction more than the lever 2 shown in FIG. I take the attitude. The positioning member 5 can take an arbitrary rotation angle by the motor 16, and the difference in the rotation posture of the lever 2 is caused by the rotation angle of the positioning member 5. In FIG. 6, the positioning member 5 is in contact with the lever 2 at a position 5a having a small radius, and in FIG. 7, the positioning member 5 is in contact with the lever 2 at a position 5b having a large radius. Thus, the posture of the lever 2 is determined by which part of the positioning member 5 the contact portion 2a of the lever 2 contacts, and this can be determined by the rotation angle of the positioning member 5.

  When the turning posture of the lever 2 changes, the distance between the place where the head base positioning member 10a and the bearing 4 are in contact with the platen roller 1 changes. This distance is Xa in FIG. 6, Xb in FIG. 7, and a relationship of Xa> Xb. That is, when the lever 2 rotates in the e direction, the bearing 4 relatively moves in the a direction as viewed from the rotation center of the lever 2. However, the platen unit 6 moves in the b direction so that the bearing 4 contacts the head base positioning member 10a as described above. As a result, the distance in the a or b direction (Xa in FIG. 6 and Xb in FIG. 7) between the position where the bearing 4 and the head base positioning member 10 a are in contact with the rotation center of the lever 2 is the rotational position of the positioning member 5. Dependent. Therefore, the posture of the lever 2 is determined by adjusting the rotation angle of the positioning member 5, and the rotation center of the lever 2, that is, the relative position between the platen roller 1 and the bearing 4 is determined by the posture of the lever 2.

  As described above, the bearing 4 is in contact with the positioning member 10 a during printing, and the positioning member 10 a and the thermal head 9 are fixed to the head base 10, so the contact position between the platen roller 1 and the thermal head 9 is determined. Is done.

  That is, the contact position adjusting mechanism includes a platen unit 6 that is movable and biased in a predetermined width direction of the thermal head 9, a lever 2 that rotates around a predetermined axis on the platen unit 6, and a platen unit. 6 is fixed on the head base 10 and a positioning member 5 as a rotation attitude determining member that determines a rotation attitude of the lever 2 by contacting a contact portion 2a as a first end of the lever 2. The contact portion 2 a of the lever 2 includes a second end portion (position of the bearing 4) at the other end and a head base positioning member 10 a that abuts on the downstream side of the urging force applied to the platen unit 6. When the platen unit 6 moves in the predetermined width direction according to the moving posture, the contact position of the platen roller 1 and the thermal head 9 is adjusted. Thereby, the rotation posture of the lever 2 is determined by a small driving force for rotating the positioning member 5 as the rotation posture determination member, and the predetermined width direction in the thermal head 9 of the platen unit 6 is determined by the rotation posture of the lever 2. It is possible to change the contact position between the platen roller 1 and the thermal head 9.

  The printer according to the first embodiment is configured to have the above-described platen roller positioning mechanism. Thereby, a printer capable of changing the contact position between the platen roller 1 and the thermal head 9 can be realized.

  In the above description, the lever 2 is fitted to both ends of the platen roller 1 and rotates around the rotation axis of the platen roller 1. However, this is not always necessary, and the platen roller 1 is not necessarily related to the lever 2. It may be supported by the unit 6. If the lever 2 is supported by the platen unit 6, the platen unit 6 can be moved according to the turning posture of the lever 2, and the contact position between the platen roller 1 and the thermal head 9 can be changed.

<Effect>
The platen roller positioning mechanism according to the first embodiment includes a platen roller 1, a thermal head 9 having a predetermined width in the tangential direction of the platen roller 1, and the platen roller 1 and the thermal head 9 are paired to sandwich the printing paper. A relative position changing mechanism that changes the relative position of the platen roller 1 and the thermal head 9 so as to press, and a contact position adjustment that arbitrarily adjusts the contact position when the platen roller 1 and the thermal head 9 are pinched in a predetermined width direction. And a mechanism. As a result, the contact position between the platen roller 1 and the thermal head 9 can be arbitrarily adjusted according to the temperature inside and outside the printer, the photographic paper, the print image, and the color density, and high-quality printing can be performed. .

  Further, the relative position changing mechanism includes a head base 10 that fixes the thermal head 9, and a platen unit 6 that supports the platen roller 1 and moves so that the platen roller 1 contacts and separates from the thermal head 9. Since the platen unit 6 and the platen roller 1 are lighter than the head base 10, the relative position of the platen roller 1 and the thermal head 9 is changed with a smaller driving force than when the thermal head 9 is moved together with the head base 10. The platen roller 1 can be positioned.

  The contact position adjusting mechanism includes a platen unit 6 that is movable and biased in a predetermined width direction of the thermal head 9, a lever that rotates about a predetermined axis on the platen unit 6, and the platen unit 6. Fixed on the head base 10 and a positioning member 5 as a rotation posture determining member fixed on the contact portion 2a as the first end of the lever 2 and determining the rotation posture of the lever 2; The contact portion 2 a of the lever 2 includes a second end portion at the other end and a head base positioning member 10 a that abuts on the downstream side of the urging force applied to the platen unit 6, and the platen unit according to the turning posture of the lever 2. When 6 moves in the predetermined width direction, the contact position of the platen roller 1 and the thermal head 9 is adjusted. Thereby, the rotation posture of the lever 2 is determined by a small driving force for rotating the positioning member 5 as the rotation posture determination member, and the predetermined width direction in the thermal head 9 of the platen unit 6 is determined by the rotation posture of the lever 2. It is possible to change the contact position between the platen roller 1 and the thermal head 9.

  Moreover, the positioning member 5 as a rotation attitude | position determination member is an eccentric cam which can control a rotation angle. As a result, the turning posture of the lever 2 can be adjusted by the rotational posture of the positioning member 5.

  Further, the predetermined axis that becomes the rotation center of the lever 2 is the rotation axis of the platen roller 1, and the lever 2 is fitted into both ends of the platen roller 1 with the platen roller 1 being rotatable. Space saving compared to the case where the lever 2 and the platen roller 1 are independently grounded to the platen unit 6 by installing the lever 2 so that the rotation center of the lever 2 is the rotation axis of the platen roller 1. Can be planned. Furthermore, since the lever 2 is fitted into both ends of the platen roller 1, if the positioning member 5 and the head base positioning member 10 a as the rotation posture determining member are installed at both ends of the platen roller 1 in accordance with the lever 2, The rotation posture of the lever 2 can be set independently. Thereby, even if there is a manufacturing dimensional variation in each of these components, the relative position of the platen roller 1 and the thermal head 9 can be set accurately.

  The platen unit 6 includes a shaft 12 installed in parallel with the platen roller 1, and the platen unit 6 rotates relative to the shaft 12 to change the relative position of the platen roller 1 and the thermal head 9, thereby changing the shaft. When 12 moves in the predetermined width direction, the platen unit 6 moves in the predetermined width direction. When the platen unit 6 rotates, the platen roller 1 is pressed against or separated from the thermal head 9, and the platen unit 6 moves in a predetermined width direction of the thermal head 9 according to the shaft 12, whereby the platen roller 1 and the thermal head are moved. 9 contact positions can be adjusted.

  Furthermore, the contact position adjusting mechanism includes a spring that applies an urging force to the lever 2 so that the contact portion 2a as the first end portion comes into contact with the positioning member 5 as the rotation posture determining member. Thereby, the contact part 2a of the lever 2 is made to contact | abut to the positioning member 5, and the rotation attitude | position of the lever 2 can be determined.

  In addition, the relative position changing mechanism includes a bearing 4 at a portion in contact with the head base positioning member 10a as the second end portion of the lever 2. Thereby, since the bearing 4 is rotatable, even if the lever 2 is in contact with the head base positioning member 10a, the degree of freedom of the rotational movement of the platen unit 6 around the shaft 12 is not hindered.

1 is a perspective view showing a configuration of a first embodiment. FIG. 3 is a front view illustrating the shape of the positioning member according to the first embodiment. FIG. 3 is a perspective view showing a configuration around a platen unit according to the first embodiment. FIG. 3 is a perspective view showing a configuration around a platen unit according to the first embodiment. 2 is a side view showing the configuration of the first embodiment. FIG. 3 is a diagram illustrating the principle of positioning of the platen roller by the positioning member according to Embodiment 1. FIG. 3 is a diagram illustrating the principle of positioning of the platen roller by the positioning member according to Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Platen roller, 2 Lever, 3, 4 Bearing, 5 Positioning member, 6 Platen unit, 9 Thermal head, 10 Head base, 10a Head base positioning member, 12 Shaft

Claims (8)

A platen roller,
A thermal head having a predetermined width in a tangential direction of the platen roller;
A relative position changing mechanism that changes the relative position of the platen roller and the thermal head so that the platen roller and the thermal head are paired to sandwich the printing paper;
A contact position adjusting mechanism that arbitrarily adjusts the contact position during clamping of the platen roller and the thermal head in the predetermined width direction ;
The relative position change mechanism is
A head base for fixing the thermal head;
A platen unit that supports the platen roller and moves so that the platen roller contacts and separates from the thermal head;
The contact position adjusting mechanism is
The platen unit that is movable and biased in the predetermined width direction;
A lever that rotates about a predetermined axis on the platen unit;
A rotation attitude determination member fixed on the platen unit and determining the rotation attitude of the lever by contacting the first end of the lever;
A head base positioning member fixed on the head base and abutting on the downstream side of the biasing force applied to the second end portion of the lever and the platen unit;
Adjusting the contact position of the platen roller and the thermal head by moving the platen unit in the predetermined width direction according to the pivoting posture of the lever;
Platen roller positioning mechanism. The turning posture determining member is an eccentric cam capable of controlling a turning angle.
The platen roller positioning mechanism according to claim 1. The predetermined axis serving as a rotation center of the lever is a rotation axis of the platen roller,
The lever is fitted to both ends of the platen roller so that the platen roller is rotatable.
The positioning mechanism of the platen roller according to claim 1 or 2. The platen unit includes a shaft installed in parallel with the platen roller,
The platen unit changes the relative position of the platen roller and the thermal head by rotating about the shaft.
When the shaft moves in the predetermined width direction, the platen unit moves in the predetermined width direction.
The positioning mechanism of the platen roller according to any one of claims 1 to 3. The contact position adjusting mechanism further includes a spring that applies an urging force to the lever so that the first end portion comes into contact with the rotation posture determining member.
The platen roller positioning mechanism according to claim 4. The relative position change mechanism further includes a bearing provided at a second end of the lever.
The platen roller positioning mechanism according to claim 4. A printer comprising the platen roller positioning mechanism according to claim 1. The platen roller is located above the thermal head;
The printer according to claim 7.

Images