JPH0761000A - Print head control device of dot impact printer - Google Patents

Abstract

PURPOSE:To obtain a print head control device in which the operation of a print head in the low temperature is improved by providing a control section that activate a solenoid before printing when the temperature of the solenoid detected by a temperature sensor is lower than a prescribed value. CONSTITUTION:The variation of resistance values of a thermistor 3 are changed to the variation of voltage values and are converted to digital values by an analog-digital convertor 4 to be transmitted to a micro processor 5. The processor 5 compares an output value from the convertor 4 with a predetermined value stored in a ROM 6 just before starting the printing so that it is judged whether a temperature of the solenoid is low or not. When it is not low, the processor 5 executes a normal printing operation. When it is low, the processor 5 executes a pre-operation before printing, that is, the processor 5 outputs a signal for operating a motor 9 to a motor drive circuit 8 to move a print head 1 outside a printing region of a platen 1. Then, a command signal of activating the solenoid 2 is outputted to a print head drive circuit 7 to drive each dot pin of the print head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head controller for a dot impact printer, and more particularly to a print head controller for improving the operation of the print head at low temperatures.

[0002]

2. Description of the Related Art A conventional print head controller of this type is
For example, it is described in JP-A-2-219660. These print head control devices detect the temperature of the solenoid of the print head from the resistance value of the thermistor in the print head, and control the driving force of the solenoid so that the printing pressure becomes optimum at each temperature.

[0003]

However, especially when the entire printer is not warmed up immediately after the power is turned on,
Since the temperature is partially low, the frictional resistance of the dot pin, the guide system, etc. becomes large, and the ink adhering to the dot pin becomes hard. In this case, even if only the driving force of the solenoid is controlled by the conventional print head control device, the operation of the dot pin becomes unstable and the normal print result cannot be obtained.

[0004]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a print head controller which improves the operation of the print head at low temperatures.

[0005]

The print head control device according to the present invention is made to achieve the above object, and is provided in contact with a solenoid for driving a dot pin in the print head and this solenoid is also provided. A temperature sensor for detecting the temperature of the solenoid and a controller for energizing the solenoid before printing is started when the temperature of the solenoid detected by the temperature sensor is below a certain value.

Further, a motor for moving the print head in the row direction, a temperature sensor provided in contact with a solenoid for driving a dot pin in the print head and detecting the temperature of the solenoid, and the temperature sensor detect the temperature. A control unit may be provided which, when the temperature of the solenoid is equal to or lower than a certain value, causes the motor to move the print head out of the printing range of the platen to energize the solenoid.

[0007]

The temperature sensor detects the temperature of the dot pin driving solenoid in the print head. When the temperature of the solenoid is below a certain value, the control unit energizes the solenoid before starting printing. As a result, the temperature of the entire print head and the like rises.

[0008]

The present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention, FIG. 1 is a block diagram, and FIG. 2 is an operation mechanism diagram.

The print head controller according to the present invention is provided in contact with a motor 9 for moving the print head 1 in the row direction and a solenoid 2 for driving a dot pin in the print head 1 and detects the temperature of the solenoid 2. When the temperature of the thermistor 3 as a temperature sensor and the temperature of the solenoid 2 detected by the thermistor 3 are below a certain value, the motor 9 moves the print head 1 out of the printing range 11a of the platen 11 to energize the solenoid 2. And a control unit 20.

The driving force of the motor 9 is transmitted to the print head 1 by the belt 12 so that the print head 1 moves in the row direction.

A DC power supply voltage Vcc is applied to the series circuit of the thermistor 3 and the resistor 3r. Thermistor 3
Has a resistance value that changes depending on the temperature of the solenoid 2.
The resistance value of the thermistor 3 becomes a voltage value, which is converted into digital data by the analog-digital converter 4 and transmitted to the microprocessor 5. The microprocessor 5
The value output from the analog-digital converter 4 and RO
Whether or not the temperature of the solenoid 2 is low is determined by comparing a predetermined value stored in M6 immediately before the start of printing.

As a result of the comparison, when it is determined that the temperature of the solenoid 2 is not low, the microprocessor 5 executes a normal printing operation.

When it is determined that the temperature of the solenoid 2 is low, the microprocessor 5 performs a preliminary operation before starting printing. That is, the microprocessor 5 outputs a signal for moving the motor 9 to the motor drive circuit 8 to move the print head 1 to the outside of the print range 11 a of the platen 11. Then, a command signal for energizing the solenoid 2 is output to the print head drive circuit 7 to drive each dot pin of the print head 1.

After the completion of this preliminary operation, the microprocessor 5 executes a normal printing operation. In this case, the dot pins, the guide system, etc., which had a low temperature immediately after the power was turned on,
The temperature is rising due to the above preliminary operation. Therefore, the frictional resistance is reduced and the operation of the dot pin is stabilized, so that a normal printing result is obtained.

[0015]

As described above, according to the present invention, when the temperature of the solenoid in the print head is below a certain value, the control section energizes the solenoid before starting printing, so that the print head It is possible to raise the temperature of the whole such as, and especially to stabilize the printing operation immediately after the power is turned on.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is an operating mechanism diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Print Head 2 Solenoid 3 Thermistor (Temperature Sensor) 9 Motor 20 Controller

Claims (2)

[Claims] 1. A temperature sensor which is provided in contact with a solenoid for driving a dot pin in a print head and detects the temperature of the solenoid, and the temperature of the solenoid detected by the temperature sensor is below a certain value. A print head control device for a dot impact printer, comprising: a controller for energizing the solenoid before starting printing. 2. A motor for moving the print head in a row direction, a temperature sensor provided in contact with a solenoid for driving a dot pin in the print head and detecting the temperature of the solenoid, and a temperature sensor for detecting the temperature of the solenoid. A printing unit for a dot impact printer, comprising: a control unit that moves the print head out of a printing range of a platen by the motor to energize the solenoid when the temperature of the solenoid is below a certain value. Head control device.