JPS6249879B2 - - Google Patents

Description

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

In the printing operation of a thermal printer, a thermal head is pressed into 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 the form of dots. , 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.

Conventional head pressurizing devices for performing the above operations are equipped with a drive source such as a solenoid.
Some devices have been devised that allow the thermal head to move 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 small and wide notches extending in the moving direction in a carriage equipped with a thermal head, and also cuts out a driver driven by a wire or the like. The carriage is moved through the drive element, and the drive element 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 of a thermal printer according to the present invention according to its operation, FIG. 3 is a sectional view of FIG. 2, and FIG. 4 is a section of the head pressurizing device. FIG.

Reference numeral 1 in the figure is a resin base. A notch 1a is formed at the front of the 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. This 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 an inclined surface. This 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 attached to 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 these rollers 5 and 6. By rotating this paper feed roller 5, the thermal paper 4 is sent upward,
Setting to the print 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 this carriage 9 is connected to the platen 2.
The thermal head 10 is sloped at approximately the same angle as the paper support surface 2a of the head holding surface 9a.
is retained. Further, a notch 11 is formed on the upper surface of the carriage 9 in a portion facing the guide surface 1b of the base 1. This notch 11 extends along the direction of movement of the carriage 9. The left side of this notch 11 is a narrow part 11a, and the right side is a wide part 11b. Further, the narrow portion 11a and the wide portion 11b are continuous via the slope 11c. Then, a driver 12 is inserted into the notch 11.
is intervening. 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 is connected to the narrow portion 1 of the notch 11 of the carriage 9.
It has a width dimension that allows the carriage 9 to be lightly pressed in the direction of the platen 2 when inserted between the guide surface 1a and the guide surface 1b. The frictional force between the drive element 12 and the narrow portion 11a of the carriage 9 is set to be smaller than the frictional force between the platen 2 and the carriage 9. Wires 13 are connected to both ends of the driver 12 . This wire 13 is connected to pulleys 14 and 1 installed on the upper surface of both sides of the base 1.
5, and the wire 13 is connected to the drive pulley 1.
6 and is fixed. Note that the wire 13 has an appropriate tension using 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, as shown in FIG.
6 to move the driver 12 to the left in the figure via the wire 13. As shown in Figure 1,
When the driver 12 is moved to the left in the figure while the carriage 9 is stopped at the rightmost standby position,
The driver 12 intervenes from the wide part 11b of the notch 11 of the carriage 9 into the narrow part 11a. At this time, the slope 11c within the notch 11 acts as a guide surface. Further, since the drive element 12, the carriage 9, and the guide surface 1b of the base 1 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.
A thermal head 10 held in a carriage 9 is lightly pressed against the thermal paper 4. Thereafter, when the driver 12 moves to the left in the drawing, it comes into contact with the left end of the notch 11, and thereafter 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 a dot configuration are printed on the surface of the thermal paper 4.

When the carriage 9 moves to the left end in the figure and one line of printing is completed, the pulse motor reverses the drive pulley 16 and connects the drive pulley 12 to the drive element 12 via the wire 13.
Move to the right in the diagram. At the initial stage of this rightward movement, the driver 12 first moves toward the carriage 9.
The second
It moves into the wide portion 11b as shown by the dotted line in the figure. At this stage, the carriage 9 is moved by the drive element 12.
The pressing force against the thermal paper 4 is removed, and the pressing force of the thermal head 10 against the thermal paper 4 is released. Drive element 1
2 further moves to the right and comes into contact with the right end of the notch 11, after which the carriage 9 moves to the right end in the figure together with the driver 12 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
Move to the left in the diagram and print the next line.

In addition, in the standby state of the carriage 9 in Fig. 1,
When the drive element 12 is moved 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 a slight resistance is applied to the narrow portion 11a, the series of operations in which the carriage 9 starts after the driver 12 intervenes in the narrow portion 11a will be performed more reliably.

Further, in the illustrated embodiment, the guide surface 1b is formed in a planar shape, but an axis parallel to the guide shaft 7 is provided.
One side of this shaft may be used as a guide surface, and a recessed portion for moving along this axis may be formed in the driver 12.

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 by simply moving the drive element, 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) Printing operations and carriage return operations can be performed by simply 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 from the thermal head. During the operation, no extra force is applied to the thermal paper, and therefore the thermal paper is
You will be able to send lines by line.

[Brief explanation of the drawing]

1 and 2 are plan views schematically showing a head pressurizing device for a thermal printer according to the present invention,
FIG. 1 shows the carriage in a standby position, and FIG. 2 shows it in the middle of a printing operation. FIG. 3 is a cross-sectional view taken from FIG. 2, and FIG. 4 is a perspective view of the head pressurizing device. 1...Base, 1b...Guide surface, 2...Platen,
4...Thermal paper, 7...Guide shaft, 9...Carriage, 1
0... Thermal head, 11... Notch, 11a... Narrow width part, 11b... Wide part, 12... Drive element, 13... Wire, 16... Drive pulley.

Claims (1)

[Claims] 1. A carriage is movably provided between a platen and a guide surface arranged at a constant interval, a thermal head is equipped on the part of the carriage facing the platen, and a thermal head is equipped on the part facing the guide surface of the carriage. In the part where the carriage is moved, a notch is formed with a narrow width on one side and a wide cutout on the other side along the movement direction, and a driver connected to a drive source for moving the carriage is provided within this notch. When driven in one direction by a drive source, the thermal printer head pressurizes the carriage by intervening between the narrow notch and the guide surface and pressing the thermal head against the platen. Pressure device.