JPS5939561A - Heat sensitive printer - Google Patents

Abstract

PURPOSE:To provide a heat sensitive printer which always keep the thermal head tight on a paper regardless of uneven thickness thereof by having a head frame oscillably pivoted on a support shaft of a carrier mechanism above almost the center of a dot pattern. CONSTITUTION:The front of a thermal head 3 is fastened and retained on the bottom surface of a U-shaped head frame 8, which is internally inserted between arms 5a of a head holder 5 in a carrier mechanism and pivoted on a lateral frame support shaft 9. In the printing operation, the front of the thermal head 3 is kept on a paper S from above a ribbon 2 by a torque pressing of a spring 7.

Description

[Detailed description of the invention] The present invention relates to a thermal printer.

Non-impact type thermal printers use a method in which a thermal head with a dot pattern formed by heating elements is brought into close contact with the printing medium paper, thereby printing the desired dot shape on the thermal paper or transfer paper. It is being

By the way, in this method, it is necessary to ensure that the head and paper are in close contact in order to maintain good heat transfer of the drum pattern, so in the structure of conventional thermal printers, the gap between the head and the paper is Because it is difficult to adjust the thickness of the paper, it is possible to perform 0-lint only on paper with a constant thickness. This will result in unprintable or incomplete characters.

The present invention has been made to solve the above-mentioned problems, and the first object of the present invention is to always ensure that the thermal head and paper are aligned reliably and evenly in response to variations in paper thickness. An object of the present invention is to provide a thermal printer that can be brought into close contact with the printer.

As a means for achieving this first object, the thermal printer of the present invention pivots a head frame that holds a thermal head swingably on a fulcrum of a carrier mechanism located above a substantially central position of the dot pattern of the thermal head. It is characterized by being supported.

However, since the base end of a flexible cable for supplying current to each heating element is attached to the edge of the thermal head, the degree of freedom of the thermal head may be inhibited by the tension of the cable.

A second object of the present invention is to provide the thermal head with a degree of freedom of movement, arrange the current-carrying cable so as not to create unnecessary tension, and bring the thermal head and paper into close contact with each other reliably and evenly. An object of the present invention is to provide a thermal printer capable of printing.

As a means for achieving this second object, the thermal printer of the present invention holds the thermal head and is pivoted on a support shaft of the carrier mechanism located approximately at the center of the nine turns of the thermal head. The present invention is equipped with a head frame that is movably supported, and a flexible cable whose base end is the rear edge of the thermal head, and whose midway is guided rearward by making a half turn around the circumference of the support shaft. It is a feature.

The present invention will be described below based on an illustrated embodiment.

1 to 4 show the main parts of the printer of the embodiment. In the structure of this printer, the thermal head 3 is pressed against the ± sides of the immovable platen 1 via the paper S and the ribbon 2. , a dot pattern 3a (shown in FIG. 4) located on the lower surface of the front left side of the head 3 slides along the platen 1. Designed to move.

The carrier mechanism thus includes a carrier shaft 4 having a square shaft, a head holder 5 that is inserted into the carrier shaft 4 and swings together, and a drive mechanism (not shown) that pulls and drives the holder 5 in the width direction. formed, and the carrier axis 4
The bearing 4a formed near the side end is supported by the immovable part, and the pin 6 erected at the side end is pulled forward by the tension spring 7 engaged between it and the immovable part. As a result, the front extending arms 5a on both sides of the head holder 5 are biased to rotate in a lowering direction.

On the other hand, a dot pattern 3a is formed in a rectangular ceramic substrate.
The thermal head 3, which includes a plurality of heating elements forming a heating element and a plurality of parallel wires for supplying electricity to the heating elements, is fixed and held at the bottom of a head frame 8 whose front part is U-shaped. And the same frame 8 is connected to the arm 53 of the head holder 5.
The arm 5a is supported by a support shaft 9 horizontally extending between the two arms 5a with soil inserted between the arms 5a.

Further, the base end of a band-shaped flexible cable 10 that supplies electricity to each heating element is attached to the lower surface of the ridge of the thermal head 3, and the cable 10 is led forward and upward from the vicinity of the base end. The cable 10 is folded back around the front half of the support shaft 9, and then folded along the carrier shaft 4, and the slack in the middle of the cable 10 is taken up by folding.

Further, guide plates 11 and 12 for the paper S are provided at the rear and front of the platen 1, respectively, and feed rollers 1 and 12 are provided at the left and right holes of the front guide plate 12.
3 and a pinch roller 14 are provided, and the sheet S inserted between the platen 1 and the ribbon 2 along the guide plate 11 is guided by the guide plate 12 and transferred between the rollers 13 and 14. It is designed so that it can be pinched and twisted.

During the printing operation, the front part of the thermal head 3 comes into close contact with the paper S from the soil of the IJ and xj corners 2 due to the torque pressure of the elasticity of the spring 7, and in this state, while intermittently printing dots, the front part of the thermal head 3 contacts the paper S in the width direction while printing dots intermittently. 1/ The thermal head 3 slides on the tape ribbon 2 to finish printing one line, then sends the paper S and the ribbon 2, returns to its original position and slides, and repeats this process. .

As described above, in the thermal printer of the embodiment in which the thermal head 3 is swingably held in the carrier mechanism via the head frame 8, when printing one sheet of paper S, as shown in FIG. As shown in (a), the holder arm 5a
The thermal head 3 and the thermal head 3 are in close contact with the paper S on the platen 1 in a horizontally parallel state, and when printing on the thick part 15 of the bound paper Sl such as a bankbook, the thermal head 3's driver is ) of? The turn 3a is uniformly brought into close contact with the same portion 15.

Therefore, during each dot cylinder, the heat generated by the pattern is always well transmitted to the ribbon 2 (not shown in Fig. 5), and the carbon on the bottom surface of the ribbon that is in contact with the pattern is clearly melted and transferred. This allows you to obtain accurate printing operation.

Further, the flexible cable 10 is connected to the head frame 8
The soil is once guided to the support shaft 9 that forms the center of oscillation, and is folded back, so that it can be printed on a single sheet of paper S as shown in , holder arm 5
Even when the thermal head 3a and the thermal head 3 are both horizontal, as shown in FIG. Even when the thermal head 3 is pushed up, as shown in FIG. 5(C), the binding paper S! Thermal head 3 is used to print on the thick part of the
Even when the flexible cable 100 is tilted slightly counterclockwise, the distance between the base end of the flexible cable 100 and the folded part around the support shaft 9 hardly changes, and therefore the thickness of the paper changes. Also, no tension is generated in the cable 10, and as a result, the thermal head 3 can freely move according to the thickness of the paper, and good printing operation can be obtained.

As described above, according to the present invention, the head frame that holds the thermal head is pivotably supported on the support shaft of the carrier mechanism located above the approximately central position of the dot turn. In response to variations in the thickness of the print media, it is now possible to keep the head and turn of the thermal head in close contact with the paper, and as a result, even when printing paper with variable thickness, such as passbooks, etc.
Clear printing can be performed without any restrictions, which has the effect of expanding the usability of thermal printers.

According to the present invention, the thermal head is swingably held in the carrier mechanism, and the flexible cable whose base end is the rear edge of the thermal head 3 is connected to the rear by the soil that has been guided around the spindle of the head frame. Since the structure is such that the thermal head can be pulled out, there is an effect that the degree of freedom of the thermal head is not affected in any way.

[Brief Description of the Drawings] Fig. 1 is a plan view of a thermal printer showing an embodiment of the present invention, Fig. 2 is a side view thereof, Fig. 3 is a rear view thereof, and Fig. 4 is a
5(a) is a diagram showing the main part of FIG. 2 with the ribbon removed, FIG. 5(b) and FIG. 5(C) are separated perspective views of the same main part. It is an explanatory diagram of the action of figure (a). 1...Platen, 3...Thermal head, 3a...
- Dot pattern, 5... Head holder of carrier mechanism, 8... Head frame, 9... Support shaft, 10...
・Flexible cable. Patent Applicant Anritsu Electric Co., Ltd. NEC Corporation Representative Patent Attorney Norihiro Nishimura Mitsutake “Zumma J” Figure 4 Figure 5 (0) (b) (C)

Claims (2)

[Claims] (1) In a heat-sensitive solinter equipped with a frame frame for a head that holds a thermal head and a carrier mechanism for moving the thermal head along a platen by pressing it against the platen, the frame is placed above a position approximately in the center of the dot pattern of the thermal head. A thermal printer characterized in that the printer is pivotably supported on the fulcrum of the carrier mechanism. (2) In a thermal printer having a head frame that holds a thermal head and a carrier mechanism that presses and moves the thermal head along a platen, the framer is located approximately in the center of the thermal head. The thermal head is pivotably supported on a fulcrum of the carrier mechanism located above, and the rear edge of the thermal head is the base end, and the middle part thereof is guided rearward by half a rotation around the circumference of the support shaft. A thermal printer characterized by being equipped with a flexible cable.