JPH04296569A - Thermal printer - Google Patents

Abstract

PURPOSE:To obtain a thermal printer which allows the gap between a thermal head and a platen to be opened wide when the thermal head is separated form the platen and further, allows the platen and the the thermal element of the thermal head to be positioned accurately and maintained parallel with high precision, when the thermal head is pressed against the platen. CONSTITUTION:A thermal head 11 can be set wide open from a platen 2 by separating a fulcrum at which a top chassis is pivotally supported by a bottom chassis 1, from a position where the platen 2 is located. In addition, if the top chassis 5 is closed against the bottom chassis 1 and the thermal bead 11 is pressed against the platen 2, a protrusion 7 provided on a thermal head retainer plate 6 becomes engaged with a recessed part 4 provided on side plates 1a, 1b to perform the positional matching of the thermal head 11 with the platen 2 in a lateral and a height direction. Thus the positional accuracy and high parallelism of a thermal element provided in the thermal head 11, and the platen 2 are ensured.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer.

0002

2. Description of the Related Art FIG. 4 shows the configuration of a conventional thermal printer. In FIG. 4, 101 is a platen, 102 is a platen shaft, 103 is a thermal head holding plate, 104 is a shaft for rotating the thermal head, and 105 is a thermal head. In a conventional thermal printer with such a configuration, a thermal head holding plate 103 is installed near the platen 101.
A shaft 104 for rotating the thermal head 105 is fixed parallel to the platen shaft 102, and the thermal head 105 is mounted on the thermal head holding plate 1.
The rotation of the thermal head 105 brings the thermal head into pressure contact with the platen 101, and thermally drives the heating element on the thermal head 105, thereby performing thermal printing on the thermal paper.

0003

[Problems to be Solved by the Invention] However, in a thermal printer configured as described above, the thermal head 1
05 is pressed against the platen 101, the platen 101
In order to maintain a high degree of positional accuracy and parallelism between the heating element attached to the thermal head 105 and the heating element attached to the thermal head 105, it is necessary to arrange the rotation axis of the thermal head holding plate 103 near the platen axis 102. However, if the rotation axis of the thermal head holding plate 103 is placed near the platen shaft 102, it is difficult to increase the space between the thermal head 105 and the platen 101 when the thermal head 105 is separated from the platen 101. However, there has been a problem in that it is extremely difficult to pass thermal paper, ink ribbon, etc. between the thermal head 105 and the platen 101.

The present invention is an attempt to solve the above-mentioned conventional problems.When the thermal head is separated from the platen, the space between the thermal head and the platen can be widened, and when the thermal head is pressed against the platen, the gap between the thermal head and the platen can be widened. It is an object of the present invention to provide a thermal printer in which positional accuracy and parallelism between the heating element of the thermal head and the heating element of the thermal head are precisely maintained.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the thermal printer of the present invention has a platen rotatably attached to a lower chassis having a pair of side plates, and a platen is rotatably attached to a lower chassis having a pair of side plates. The thermal head is installed via a thermal head holding plate on the upper chassis that can be opened and closed around a provided fulcrum.When the upper chassis is closed against the lower chassis and the thermal head is pressed against the platen, the thermal The protrusions provided on the head holding plate fit into the recesses provided on the side plate, aligning the thermal head with respect to the platen in the front-rear direction and height direction, thereby ensuring the positional accuracy and parallelism of the heating elements of the platen and thermal head. The thermal printer is configured to maintain precision.

[0006]

[Operation] According to the above-described means, by arranging the fulcrum shaft for opening and closing the lower chassis and upper chassis of the thermal printer and the platen shaft apart from each other, when the thermal head is separated from the platen, the distance between the thermal head and the platen is maintained. It can be opened wide. Furthermore, when the thermal head and the platen are pressed together, the protrusion provided on the thermal head holding plate fits into the recess provided near the platen axis on the side plate of the lower chassis, and the thermal head is moved in the front-rear direction and height direction relative to the platen. By aligning the
It is possible to precisely maintain the positional accuracy and parallelism of the heating elements of the platen and thermal head.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the thermal printer of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of an embodiment of the thermal printer of the present invention, and FIG.
A) to FIG. 2(d) show enlarged views of the main parts of the printer. Further, FIG. 3 shows a perspective view of the thermal printing section.

FIG. 1, FIG. 2(a) to FIG. 2(d) and FIG. 3
, 1 is a lower chassis, 1a and 1b are a pair of side plates constituting the lower chassis 1, 2 is a platen, 3 is a motor that drives the rotation of the platen 2, and 4 is the lower chassis 1.
5 is an upper chassis, 6 is a thermal head holding plate, 7 is a protrusion provided on the thermal head holding plate 6, and 8 is a recess provided on the upper chassis 5 into which the protrusion 7 is inserted. hole, 9 is coil spring, 10
11 is a pin that regulates the movement of the thermal head holding plate 6;
1 is a thermal head, 12 is a fulcrum shaft for opening and closing the upper chassis 5, 13 is a locking claw, 14 is a pin that engages with the locking claw 13, 15 is a release lever that unlocks the locking claw 13, and 16 is a thermal paper. , 17 is a heating element, and 18 is a printing section printed by a thermal printer.

In the above configuration, the lower chassis 1 is configured such that the pair of side plates 1a and 1b hold the platen 2 from both sides, and the platen 2 is
A motor 3 is attached to drive the rotation of. Further, a semicircular recess 4 is provided in the side plates 1a and 1b near the bearing hole of the platen shaft 2a. Upper chassis 5
The thermal head holding plate 6 is attached in such a manner that protrusions 7 provided on the side surfaces of the thermal head holding plate 6 are passed through holes 8 provided on both sides of the upper chassis 5. A coil spring 9 is attached to the upper side of the thermal head holding plate 6, and applies a pressing force to the thermal head holding plate 6 in the direction of arrow A in FIG. 9 prevents the action of the pressing force applied to the thermal head holding plate 6. A thermal head 11 is fixed to the lower side of the thermal head holding plate 6, and the upper chassis 5 opens and closes with respect to the lower chassis 1 using a fulcrum shaft 12 as a fulcrum. When the upper chassis 5 is closed to the lower chassis 1 side, lock claws 13 attached to the upper chassis 5 are caught on pins 14 of the side plates 1a and 1b, and the upper chassis 5 is locked against the lower chassis 1 so that it does not open. The upper chassis 5 can be opened relative to the lower chassis 1 by turning a release lever 15 connected to the lock pawl 13 and removing the lock pawl 13 from the pin 14.

The operation of the thermal printer configured as described above will be explained using FIGS. 2(a) to 2(d).

First, as shown in FIG. 2(a), the upper chassis 5
When the is opened to the lower chassis 1, the thermal paper 16 is attached, and the upper chassis 5 is closed to the lower chassis 1, as shown in FIG.
As shown in (b), the thermal head 11 comes into contact with the platen 2 with the thermal paper 16 sandwiched therebetween. Next, as shown in FIG. 2(c), the projections 7 provided on the side surfaces of the thermal head holding plate 6 fit into the recesses 4 provided in the side plates 1a and 1b of the lower chassis 1, and the thermal head 11 is attached to the platen 2. Perform alignment. Furthermore, when the upper chassis 5 is closed and in the state shown in FIG. 2(d), the spring force of the coil spring 9 shown by arrow B is the pressure contact force between the recess 4 and the protrusion 7 on both sides shown by arrow D, and the thermal head shown by arrow C. Branched into 11 pressure contact forces,
At the same time as the thermal head 11 and the platen 2 are brought into pressure contact, the protrusion 7 is prevented from rising from the recess 4, thereby preventing the thermal head 11 and the platen 2 from being misaligned.

In the state shown in FIG. 2(d), the lock claw 13 is attached to the pin 1.
4 and the upper chassis 5 is fixed to the lower chassis 1. At this time, the motor 3 is driven to feed the thermal paper 16, and the thermal head 11 is synchronized with the feeding of the thermal paper 16.
By thermally driving the heating elements 17 arranged in a straight line, thermal printing is performed by thermally coloring only the portion of the heating element 17 that generates heat, as shown in FIG.

[0013]

Effects of the Invention As is clear from the above description, according to the present invention, the thermal printer is arranged with the opening/closing fulcrum of the lower chassis and upper chassis separated from the platen axis, and the thermal head is separated from the platen. The gap between the platens can be widened, and when the thermal head and platen are pressed together, the protrusion provided on the thermal head holding plate fits into the recess provided near the platen on the side plate of the lower chassis, and the thermal radiation against the platen shaft is By aligning the head in the longitudinal and height directions, it is possible to achieve the effect of precisely maintaining the positional accuracy and parallelism of the heating element of the platen and the thermal head, and to realize a thermal printer with good operability.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of a thermal printer of the present invention.

[Figure 2] (a) is an enlarged view of the main parts when the upper chassis is open; (b) is an enlarged view of the main parts in one process of closing the upper chassis; (c) is an enlarged view of the main parts in another process of closing the upper chassis; (d) is an enlarged view of the main parts with the upper chassis completely closed.

[Figure 3] Perspective view of thermal printing section

[Figure 4] A perspective view of the main parts of a conventional thermal printer

[Explanation of symbols]

1 Lower chassis 1a, 1b side plate 2 Platen 4 Recessed part 5 Upper chassis 6 Thermal head holding plate 7.Protrusion 11 Thermal head 17 Heating element

Claims (1)

[Claims] Claim 1: A platen is rotatably disposed on a lower chassis having a pair of side plates, and a thermal head is held on an upper chassis that is engaged with the lower chassis with a fulcrum pin so that it can be opened and closed with respect to the lower chassis. In a thermal printer with a thermal head attached via a plate, when the upper chassis is closed to the lower chassis and the thermal head is pressed against the platen, the protrusion provided on the thermal head may fit into the recess provided on the side plate of the lower chassis. A thermal printer configured so that the relative positional accuracy and parallelism of the heating element of the platen and the thermal head are precisely maintained by fitting and aligning the thermal head with respect to the platen in the front-rear direction and height direction.