JP2006224415A - Platen roller driving unit for thermal printer, and thermal printer equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the selection for a type from which a platen roller is detachable and a type from which the platen roller is not detachable to be performed at the time of building up. <P>SOLUTION: A first transmission gear 7 is engaged with a gear 6 for a motor, a second transmission gear 8 is engaged with the first transmission gear 7, and a gear 4 or the platen roller is engaged with the second transmission gear 8, and thus, the driving force of the motor 5 is transmitted to the shaft 2 of the platen roller. The position of a second supporting shaft 10 is a position where the second transmission gear 8 is not made to exist on the moving orbit of the gear 4 for the platen roller when the shaft 2 of the platen roller is removed from a slit 3. The position of a third supporting shaft 11 is a position where the second transmission gear 8 is made to exist on the moving orbit of the gear 4 for the platen roller when the shaft 2 of the platen roller is removed from the slit 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal printer that forms an image on thermal printing paper using a thermal head, and in particular, a type in which a platen roller cannot be detached from a main body frame during assembly (hereinafter referred to as an autoloading type) and a platen roller in the main body. The present invention relates to a printer structure that can be selected for any printer of a type that is detachable from a frame (hereinafter referred to as a clamshell type).

  Conventional thermal printers include an autoloading type and a clamshell type (see Patent Document 1).

  FIG. 4 is a cross-sectional view showing a configuration example of an autoloading type thermal printer. In this type, the platen roller 101 is rotatably supported by the main body frame 102 via a bearing (not shown). The support 105 of the thermal head 103 rotatably supported by the main body frame 102 by the support shaft 104 is applied by the biasing force of the pressure spring 106 so that the thermal head 103 is pressed against the platen roller 101. It is energized. Further, the printer is configured such that the thermal head 103 can be separated from the platen roller 101 so that a gap is formed between the thermal head 103 and the platen roller 101 during maintenance such as head cleaning.

  In this type of printer, the thermal head 103 is held in pressure contact with the platen roller 101, the leading end of the printing paper is held at the contact point, and the printing paper is loaded between the platen roller 101 and the thermal head 103 by rotating the platen roller 101. (So-called auto-loading method) is adopted. In this printer, since the platen roller 101 is installed with high positioning accuracy with respect to the main body frame 102, stable and good printing can be maintained.

  Another type is a clamshell type.

  FIG. 5 is a cross-sectional view showing a configuration example of a clamshell type thermal printer. In this type, a slit 107 is provided in the main body frame 102 of the printer for mounting the bearing 108 of the platen roller 101. The platen roller 101 is supported by the slit 107 of the main body frame 102 via the bearing 108. The support 105 of the thermal head 103 rotatably supported by the main body frame 102 by the support shaft 104 is applied by the biasing force of the pressure spring 106 so that the thermal head 103 is pressed against the platen roller 101. As a result, the bearing 108 of the platen roller 101 is locked in the slit 107.

  In this type of printer, when loading printing paper, the platen roller 101 is lifted off the main body frame 102 and then removed, and then the printing paper is dropped into the printer main body 102. Thereafter, as shown in FIG. By mounting on the frame 102, printing paper is loaded between the thermal head 103 and the platen roller 101. For this reason, it is not necessary for the user to search the paper insertion slot, and the paper loading operation is simple. Further, since the platen roller 101 is detachable from the main body frame 102, maintenance work is also easy.

In this way, both types have different characteristics, but the user purchases a desired type of printer according to his / her intended purpose.
JP 2000-318260 A

  In order to manufacture a thermal printer having two different characteristics as described above, the manufacturer must prepare parts for each type and manufacture them on a dedicated manufacturing line. For this reason, there are problems that the types of parts increase, and parts inventory and product costs increase.

  Therefore, in view of the above-described problems of the prior art, the present invention is configured so that the platen roller can be selected between a removable type and a non-detachable type at the time of assembly in order to reduce the types of components and the product cost. It is an object of the present invention to provide a platen roller drive unit for a thermal printer.

In order to achieve the above object, the present invention provides a platen roller drive unit in a thermal printer, comprising a main body frame having a slit for detachably receiving a shaft of the platen roller, and the platen roller attached to the main body frame. A motor that rotates the motor, a transmission gear that transmits the driving force of the motor to a platen roller gear attached to the shaft of the platen roller, and a projection that protrudes from the main body frame to rotatably support the transmission gear. And a support shaft that
The support shaft is provided in two places, and one support shaft is in a position where the transmission gear does not exist on the movement trajectory of the platen roller gear when the platen roller shaft is removed from the slit, The support shaft is located at a position where the transmission gear is present on a movement locus of the platen roller gear when the platen roller shaft is removed from the slit.

  In such a configuration, when the transmission gear is attached to one support shaft during assembly, the platen roller can be detached from the main body frame. When the transmission gear is attached to the other support shaft, the platen roller is attached to the main body. This type of printer cannot be removed from the frame. That is, it is possible to select either a clamshell type printer or an autoloading type printer at the time of assembly.

  The present invention also provides a thermal printer comprising the platen roller drive unit described above and a thermal head arranged so as to press the platen roller mounted on a slit of a main body frame of the platen roller drive unit. Can do.

  According to the present invention described above, it is possible to select a type in which the platen roller can be attached / detached and a type in which the platen roller cannot be attached / detached during assembly. For this reason, it is not necessary to prepare components for each printer having two different characteristics, the types of components can be reduced, and the manufacturing cost can be reduced.

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

  FIG. 1 is a side view showing a platen roller driving unit (platen roller support frame) of a thermal printer according to an embodiment of the present invention.

  As shown in this figure, the main body frame 1 is formed with a slit 3 that detachably receives the platen roller shaft 2, and the platen roller shaft 2 is supported in the slit 3. A platen roller gear 4 is attached to the shaft 2 of the platen roller. Although not shown, the thermal head is pressed against the platen roller with the same configuration as the example shown in FIG.

  A motor 5 for rotating the platen roller is attached to the main body frame 1, and a rotation shaft of the motor 5 protrudes from the main body frame 1 so as to be rotatable. A motor gear 6 is attached to the rotating shaft.

  In order to transmit the driving force of the motor 5 to the platen roller gear 4 of the platen roller shaft 2 mounted in the slit 3 of the main body frame 1, two transmission gears 7, 8 are provided between the gear 4 and the gear 6. Is arranged.

  The first transmission gear 7 is rotatably attached to a first support shaft 9 projecting from the main body frame 1, and the position of the first support shaft 9 is attached to the first support shaft 9. The first transmission gear 7 is in a position where it can directly mesh with the motor gear 6.

  The second transmission gear 8 is rotatably attached to either the second support shaft 10 or the third support shaft 11 projecting from the main body frame 1, and the second support shaft 10 and the third support shaft 11 are supported. The position of the shaft 11 is a position where the second transmission shaft 10 or the second transmission gear 8 attached to the third support shaft 11 can mesh with both the first transmission gear 7 and the platen roller gear 4. It is in.

  FIG. 1 shows a case where the second transmission gear 8 is attached to the second support shaft 10, and the second transmission gear 8 when attached to the third support shaft 11 is indicated by a two-dot chain line. ing.

  As described above, the first transmission gear 7 meshes with the motor gear 6, the second transmission gear 8 meshes with the first transmission gear 7, and the platen roller gear 4 meshes with the second transmission gear 8. The driving force of the motor 5 is transmitted to the shaft 2 of the platen roller.

  Further, the positions of the second support shaft 10 and the third support shaft 11 will be described. 2 is a perspective view of the thermal printer when the second transmission gear 8 is attached to the second support shaft 10, and FIG. 3 is a thermal printer when the second transmission gear 8 is attached to the third support shaft 11. FIG.

  As shown in FIGS. 2 and 3, the platen roller 12 is rotatably supported by the main body frame 1. In the state shown in FIG. 2, the platen roller shaft 2 can be removed from the slit 3. This is because, when the second transmission gear 8 is attached to the second support shaft 10, the second transmission is on the movement locus of the platen roller gear 4 when the platen roller shaft 2 is removed from the slit 3. This is because the gear 8 does not exist. In other words, the position of the second support shaft 10 is a position where the second transmission gear 8 does not exist on the movement trajectory of the platen roller gear 4 when the platen roller shaft 2 is removed from the slit 3.

  On the other hand, in the state shown in FIG. 3, the platen roller shaft 2 cannot be removed from the slit 3. This is because, when the second transmission gear 8 is attached to the third support shaft 11, the second transmission is on the locus of the platen roller gear 4 when the platen roller shaft 2 is removed from the slit 3. This is because the gear 8 exists. That is, the platen roller gear 4 collides with the second transmission gear 8 when the platen roller shaft 2 is removed from the slit 3. Therefore, the position of the third support shaft 11 is a position where the second transmission gear 8 exists on the movement locus of the platen roller gear 4 when the platen roller shaft 2 is removed from the slit 3.

  According to the above thermal printer, at the time of assembly, by selecting either the second support shaft 10 or the third support shaft 11 as the shaft to which the second transmission gear 8 is attached, Two different printers can be manufactured. That is, when the second transmission gear 8 is attached to the second support shaft 10, the platen roller 12 is detachable from the main body frame 1, so that a clamshell type thermal printer is obtained. When the second transmission gear 8 is attached to the third support shaft 11, the platen roller shaft 2 cannot be removed from the slit 3 of the main body frame 1. Can do.

  In the present embodiment, the platen roller drive unit includes two transmission gears 7 and 8, but the motor gear 6 is directly meshed with the second transmission gear 8 instead of the first transmission gear 7. You may take such a structure. A plurality of gears between the motor gear 6 and the second transmission gear 8 may be provided.

It is a side view which shows the platen roller drive unit of the thermal printer by embodiment of this invention. It is a perspective view of a thermal printer when the 2nd transmission gear is attached to the 2nd support shaft of FIG. It is a perspective view of a thermal printer when the 2nd transmission gear is attached to the 3rd support shaft of FIG. It is sectional drawing which shows the structural example of an auto loading type thermal printer. It is sectional drawing which shows the structural example of a clamshell type thermal printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body frame 2 Platen roller shaft 3 Slit 4 Platen roller gear 5 Motor 6 Motor gear 7 First transmission gear 8 Second transmission gear 9 First support shaft 10 Second support shaft 11 Third support Shaft 12 Platen roller

Claims (2)

A drive unit for a platen roller in a thermal printer,
A body frame having a slit for detachably receiving the shaft of the platen roller;
A motor attached to the main body frame for driving the platen roller;
A transmission gear that transmits the driving force of the motor to a platen roller gear attached to the shaft of the platen roller;
A support shaft that protrudes from the main body frame and rotatably supports the transmission gear;
The support shaft is provided in two places, and one support shaft is in a position where the transmission gear does not exist on the movement trajectory of the platen roller gear when the platen roller shaft is removed from the slit, A platen roller drive unit for a thermal printer, wherein the support shaft is located at a position where the transmission gear is present on a movement locus of the platen roller gear when the platen roller shaft is removed from the slit. The platen roller drive unit according to claim 1,
A thermal printer comprising: a thermal head arranged to press a platen roller mounted on a slit of a main body frame of the platen roller driving unit.

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