JPH0557971A - Printer device - Google Patents

Abstract

PURPOSE:To provide a printer device capable of printing data under a constant printing pressure regardless of the relative position where a printing head stays with respect to a platen, the printer being of a type which prints data by allowing impact dot wire to protrude toward the platen. CONSTITUTION:The subject printer device consists of a biasing means 20 which biases a platen 3 toward a printing head 7 and a means for adjusting the biasing force of the means 20 in response to a position where the printing head 7 moves, and maintains the biasing force acting upon the platen 3 at a constant level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer device for printing by ejecting impact dot wires toward a platen.

In order to print smoothly on a medium such as a passbook in which the thickness of the portion to be printed is not constant, the thickness of the medium which is urged toward the print head without fixing the platen and passes through A so-called floating mechanism is provided so that the position of the platen can be changed automatically in response to this.

[0003]

2. Description of the Related Art In a conventional printer using a floating mechanism, for example, as shown in FIG.
I was pushing for 3. 84 is a parallel belt 8
5 is a space motor for moving the print head 83 in the space direction along the platen 81 via the motor 5.

[0004]

However, the platen 81
In the configuration in which the compression coil springs 82 are simply provided at both ends of the print head 83, as the print head 83 moves in the space direction along the platen 81, the biasing force applied to the platen 81 at the position facing the print head 83 is 5, it becomes large at the central portion and becomes small at both end portions.

This means that the printing pressure by the impact dot wire also changes with the movement of the print head, and the printing pressure is large at the center and small at both ends.

As a result, ribbon smearing occurs at high printing pressure, and print blurring occurs at low printing pressure, which is a cause of poor print quality. Therefore, it is an object of the present invention to provide a printer device capable of printing with a constant printing pressure regardless of the position of the print head with respect to the platen.

[0007]

In order to achieve the above object, the printer device of the present invention prints by projecting an impact dot wire 7a as shown in FIG. 1 for explaining an embodiment. A print head 7, a platen 3 movably arranged in the same direction as the movement direction of the impact dot wire 7a so as to face the print head 7, and a spacing for moving the print head 7 along the platen 3. The means 10 and the platen 3 are connected to the print head 7.
Urging means 20 for urging the platen 3 in response to the moving position of the print head 7, and the urging means 20 for urging the platen 3 at a position facing the print head 7. Biasing force adjusting means 16 for keeping the power constant
And is provided.

The urging means 20 is constituted by a spring 21.
And the electromagnet 24, and the magnetic force generated by the electromagnet 24 may be adjusted by the biasing force adjusting means 16.

[0009]

When the print head 7 moves along the platen 3, the biasing force adjusting means responds to the moving position of the print head 7 so that the biasing force applied to the platen 3 becomes constant at the position facing the print head 7. 16 adjusts the biasing force of the biasing means 20.

[0010]

Embodiments will be described with reference to the drawings. FIG. 1 is a plan view of a serial printer. In the figure, 1 and 2 are stay shafts and guide rails fixedly provided in parallel with the platen 3, and side frames 4 are provided at both left and right sides.
Supported by 5.

6 is an impact dot type print head 7.
Is a carriage on which is mounted, and is movably provided along the stay shaft 1 and the guide rail 2. From the tip of the print head 7, the impact dot wire 7a is driven to project toward the platen 3, and printing is performed thereby. Reference numeral 8 is a ribbon cassette, and 8a is an ink ribbon.

A parallel drive belt 11 which is rotated by a space motor 10 using a step motor is connected to the carriage 6, and the carriage 6 reciprocates to move the carriage 6 along the platen 3. Is driven back and forth. Then, as the carriage 6 moves, the print head 7 moves in the space direction along the platen 3 while facing the platen 3.

The platen 3 is movably moved toward and away from the print head 7 (that is, in the same direction as the movement direction of the impact dot wire 7a), and is supported by shafts 3a at both ends thereof, and includes a compression coil spring 21. The urging device 20 urges the print head 7 in a direction approaching the print head 7, that is, upward in FIG. A pair of biasing devices 20 are attached to the left and right side frames 4 and 5.

FIG. 2 shows an urging device in which a compression coil spring 21 for urging the iron platen shaft 3a attracted by magnetic force toward the print head 7 and the platen shaft 3a are U-shaped frames. An electromagnet 24 is slidably disposed in the coil 22, and is disposed on the opposite side of the compression coil spring 21 with the platen shaft 3a interposed therebetween. 24a is a drive circuit for the electromagnet 24. Reference numeral 25 is a yoke for forming a magnetic circuit.

Returning to FIG. 1, a control signal is input to the space control unit 15 which controls the operation of the space motor 10 from a main control unit (not shown). Also, the biasing device 2
The space control unit 1 includes the urging force control unit 16 for controlling the magnetic force by changing the magnitude of the current flowing through the electromagnet 24 of 0.
A signal indicating the number of rotation steps of the space motor 10 is given from 5.

The output signal from the urging force control section 16 is separately output to the electromagnet drive circuits 24a of the left and right urging devices 20, and the electromagnetic forces of the left and right electromagnets 24 are controlled independently.

In the printer device of the embodiment thus constructed, the platen is caused by the combined force of the spring force of the compression coil spring 21 in the urging device 20 and the force of the electromagnet 24 absorbing the platen shaft 3a. 3 is biased toward the print head 7, and the electromagnetic force of the left and right electromagnets 24 is changed under the control of the biasing force control unit 16.
The biasing force can be adjusted.

In the urging force control unit 16, the moving position of the print head 7 with respect to the platen 3 is calculated from the number of rotation steps of the space motor 10, and the urging force applied to the platen 3 at the position facing the print head 7 is always constant. The electromagnetic force of the left and right electromagnets 24 is controlled so that

FIG. 3 shows the print head 7 for the platen 3.
And the biasing force applied to the platen 3 at that position.
The urging force A due to 1 is small at both ends and large at the center. Therefore, on the contrary, the urging force B by the electromagnet 24 is small at both ends and large at the center. As a result, the total urging force C obtained by combining the two is
It is always constant regardless of the moving position of.

As a result, when impact dot printing is performed while the print head 7 moves along the platen 3, the printing pressure is always constant.

[0021]

According to the printer apparatus of the present invention, a constant printing pressure is always obtained regardless of the position of movement of the print head with respect to the platen. Therefore, high-quality printing without ribbon stains or print blurring can be achieved. It has an excellent effect that can be performed stably.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment.

FIG. 2 is a partial cross-sectional view of an example.

FIG. 3 is a diagram showing a biasing force characteristic of the embodiment.

FIG. 4 is a schematic view of a conventional example.

FIG. 5 is a diagram showing a biasing force characteristic of a conventional example.

[Explanation of symbols]

 3 Platen 7 Print Head 7a Impact Dot Wire 10 Spacing Means 16 Energizing Force Adjusting Means 20 Energizing Means

Claims (2)

[Claims] 1. A print head (7) for printing by projecting an impact dot wire (7a) and a print head (7) movably in the same direction as the movement direction of the impact dot wire (7a). And a platen (3) arranged in parallel, spacing means (10) for moving the print head (7) along the platen (3), and the platen (3) in the direction of the print head (7). And a biasing means (20) for biasing the print head (7) to adjust the biasing force of the biasing means (20) in response to the moving position of the print head (7). A printer apparatus comprising: an urging force adjusting means (16) for making the urging force applied to the platen (3) constant. 2. The biasing means (20) is a spring (2).
1) and an electromagnet (24), the electromagnet (2
The printer device according to claim 1, wherein the magnetic force generated by (4) is adjusted by the biasing force adjusting means (16).