JPS5942977A - Head press apparatus of thermal printer - Google Patents

Abstract

PURPOSE:To provide the titled apparatus for enabling the contact and the separation with heat sensitive paper of a thermal head, by a simple structure having such a mechanism that a narrow range and wide range notch parts are formed to a carriage and the movement of the carriage and the pressing of the thermal head are performed by drive elements provided in the notch parts. CONSTITUTION:A drive element 12 is moved to a left direction from the stop state of a carriage 9 to be slid into the narrow range part 11a of a notch part 11 and the carriage 9 is pushed toward a platen 2 to bring a thermal head 10 into contact with heat sensitive paper. Subsequently, the drive element 12 is further moved to a left direction to be brought into contact with the lefthand end of the notch part and the carriage 9 is moved along with the drive element 12. When printing corresponding to one line is finished, a drive pulley 16 is reversely rotated to move the drive element 12 to a right direction and the drive element 12 is moved into the wide range part 11b of the notch part to release push pressure to the carriage 9 due to the drive element 12 which is, in turn, brought into contact with the right end of the notch part 11 to move the carriage to the right end along with the drive element 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head pressurizing device for a thermal printer for pressurizing a thermal head toward a platen during operation.

In the printing operation of a thermal printer, a thermal head is brought into pressure contact with thermal paper placed on the surface of a platen, and the thermal head is moved to selectively heat multiple heating points provided on the head to print characters in a dot configuration. , a symbol is printed. In addition, when the printing operation for one line is completed and a line feed is to be performed, it is necessary to remove the pressing force of the thermal head against the thermal paper, move the thermal paper by one line, and return the thermal head to its initial position. It is.

As a conventional head pressurizing device for performing the above operation, one has been devised that is provided with a drive source such as a solenoid to move the thermal head toward and away from the platen. However, this conventional device has a large number of parts including a solenoid, and has a complicated structure, so there is a limit to the miniaturization of the entire thermal printer.

The present invention has been made in view of the above-mentioned conventional problems, and provides a head pressurizing device for a thermal printer that has an extremely simple structure, allows the thermal head to move toward and away from thermal paper, and can be miniaturized. It is intended to.

The head pressurizing device for a thermal printer according to the present invention continuously forms notches of small width and large width extending in the moving direction in a carriage equipped with a thermal head, and also inserts a driver driven by a wire or the like into the notch. The carriage is moved via the drive element, and 1. A driver is interposed between the narrow notch and the guide surface to press the thermal head toward the platen.

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are plan views showing the schematic structure of the head pressurizing device for a thermal printer according to the present invention according to its operation, FIG. 3 is a sectional view taken along the line II in FIG. 2, and FIG. 4 is a head pressurizing device according to the present invention. It is a side view of a part.

The reference numeral l in the figure is a resin base. A notch 1a is formed at the front of this base 1, and a guide surface 1b is formed at the bottom of this notch 1a. A platen 2 is installed across the notch 1a. The platen 2 is made of resin and has a cross-sectional shape as shown in FIG. 3, and the paper support surface 2a of the platen 2 is sloped. The paper support surface 2a and the guide surface 1b are opposed to each other with a constant interval therebetween. Further, a thin rubber mat 3 is pasted on the paper support surface 2a, and the thermal paper 4 is placed with this mat 3 as its back. As shown in FIG. 3, a paper feed roller 5 and a pinch roller 6 that press against the paper feed roller 5 are provided below the platen 2, and the thermal paper 4 is held between the rollers 5 and 6. This paper feed sheet roller 5
By rotating the thermal paper 4, the thermal paper 4 is fed upward, and set at the printing position and line feeding are performed.

A guide shaft 7 is provided between the guide surface 1b of the base 1 and the platen 2, and the carriage 9 is inserted through the guide shaft 7 so as to move along the guide shaft 7. This carriage 9 is made of resin and is molded into the cross-sectional shape shown in FIG. The head holding surface 9a of the carriage 9 is sloped at approximately the same angle as the paper supporting surface 2a of the platen 2, and the thermal head 1o is held on this head holding surface 9a. Further, it extends on the upper surface of the carriage 9 and along the moving direction of the carriage 9. This notch 1
The left side of 1 is the narrow part 11a, and the right side is the wide part 11.
It is b. Further, the narrow portion 11a and the wide portion 11b are continuous via the slope 11c. A driver 12 is interposed within the notch 11 . This drive element 12 is also made of resin, and has a smooth surface so that it can slide smoothly on the notch 11, especially on the narrow width part 11a and on the guide surface 1b of the base 1. Further, the driver 12 has a width dimension that acts to lightly press the carriage 9 toward the platen 2 when the driver 12 intervenes between the narrow portion 11a of the notch 11 of the carriage 9 and the guide surface 1b. ing.

The friction force between the drive element 12 and the narrow portion 11a of the carriage 9 is set smaller than the friction force between the platen 2 and the carriage 9. Wires 13 are attached to both ends of the drive element 12.
are connected. This wire 13 is installed on the upper surface of both sides of the base l. The wire 13 is wound around the driving goose J16 and is fixed thereto. Note that the wire 13 has appropriate tension by a spring or the like. The drive pulley 16 is driven by a pulse motor (not shown) installed on the base 1.

Next, the operation of the thermal printer with the above configuration will be explained.

In the printing operation, first, as shown in Fig. 3, thermal paper 4 is set on the front of mat 3 attached to platen 2, and then,
The drive pulley 16 is driven by a pulse motor to move the driver 12 to the left in the figure via the wire 13. As shown in FIG. 1, when the driver 12 is moved to the left in the figure while the carriage 9 is stopped at the standby position at the right end, the driver 12 moves to the wide part 11b of the notch 11 of the carriage 9. It then intervenes into the narrow portion 11a. At this time, the slope 11c within the notch 11 acts as a guide surface. Also,
Since the drive element 12, the carriage 9, and the guide surface 1b of the base l are made of resin and have smooth surfaces, the drive element 12 smoothly intervenes in the narrow portion 11a. When the driver 12 intervenes between the narrow portion 11a and the guide surface 1b, the carriage 9 is pushed toward the platen 2, as shown in FIG. Press lightly. After that, when the driver 12 moves to the left in the figure, it comes into contact with the left end of the notch 11, and after that,
The carriage 9 moves to the left together with the driver 12 at a constant speed. During this time, by selectively heating a plurality of heating points of the thermal head 10, predetermined characters, symbols, etc. in the form of dots are printed on the surface of the thermal paper 4.

When the carriage 9 moves to the left end in the figure and printing for one line is completed, the drive pulley 16 is reversely rotated by the pulse motor to move the driver 12 to the right in the figure via the wire 13. At the initial stage of this movement to the right, the driver 12 first comes out of the narrow part 11a of the carriage 9, and enters the wide part 11b as shown by the dotted line in FIG. Moving. At this stage, the pressing force of the driver 12 against the carriage 9 is removed, and the pressing force of the thermal head 10 against the thermal paper 4 is released. When the driver 12 further moves to the right and comes into contact with the right end of the notch 11, the carriage 9 moves together with the driver 12 to the right end in the figure and returns to the initial position in FIG. During this return operation of the carriage 9, the thermal paper 4 is not subjected to pressure by the carriage 9 as described above, so the rotation of the paper feed roller 5 allows the thermal paper 4 to be sent upward by one line. After feeding the thermal paper 4 upward by one line, the driver 12 is again moved to the left in the figure to print the next line.

Note that in the standby state of the carriage 9 in FIG.
2 to the left in the figure, the carriage 9 does not move and the drive element 12 slides into the narrow part 11a of the notch 11 and intervenes. If this is provided, the series of operations in which the carriage 9 starts after the driver 12 intervenes in the narrow portion 11a can be performed more reliably.

In the illustrated embodiment, the guide surface 1b is formed in a planar shape, but a shaft parallel to the guide shaft 7 is provided, one side of this shaft is used as a guide surface, and the drive element 12 is provided with a shaft parallel to the guide shaft 7. A recessed portion for movement along may be formed.

As described above, according to the present invention, the effects listed below are achieved.

(1) Since it is possible to move the carriage and pressurize the thermal head only by moving the driver, there is no need for a conventional drive source such as a solenoid for pressurizing the head, reducing the number of parts and simplifying the mechanism. Miniaturization can be achieved.

(2) The printing operation and the return operation of the carriage can be performed simply by reciprocating the drive element using the drive pulley, so electrical control is simple.

(3) When the driver returns to the right in the figure after printing one line, the driver moves into the wide part of the notch and releases the pressure on the thermal head. During the operation, no extra force is applied to the thermal paper, thus allowing one line of thermal paper to be advanced during this time.

[Brief explanation of drawings]

1 and 2 are plan views schematically showing a head pressure device for a thermal printer according to the present invention, in which FIG. 1 shows the carriage in a standby position, and FIG. 2 shows it in the middle of printing operation. There is. FIG. 3 is a cross-sectional view of FIG. 2, and FIG. 4 is a perspective view of the head pressurizing device. 10. Base, 1b... Guide surface, 2... Platen, 4... Thermal paper, 7... Guide shaft,
9... Carriage, 10... Thermal head, 11
...notch part, 11a river narrow part, llb... wide part, 12... drive element, 13... wire, 16... drive pulley

Claims (1)

[Claims] Between the platen and the guide surface arranged at regular intervals,
A movable carriage is provided, a thermal head is equipped on the part of the carriage facing the platen, and
In the part of the carriage facing the guide surface, a notch is formed along the movement direction, one with a small width and the other with a wide width, and within this notch is a drive connected to a drive source for moving the carriage. When driven in one direction by a drive source, this driver intervenes between the narrow notch and the guide surface, and moves the carriage while pressing the thermal head against the platen. Thermal printer head pressure device.