JPH05338218A - Controlling printing of dot impact printer - Google Patents

Abstract

PURPOSE:To provide a method for controlling a dot impact printer which controls printing properly corresponding to the temperature of a solenoid coil and independently of the orientation of printing letters. CONSTITUTION:A microprocessor 41 detects the temperature of a printing head by measuring the resistance of a thermistor 52 attached on the printing head with an A/D converter 51 and controls the printing speed on the basis of the comparison between the first and second temperatures which are stored previously in ROM 42 according to the orientation of printing letters, so that the burning of the print head and the unnecessary reduction in printing speed are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print control method for a dot impact printer.

[0002]

2. Description of the Related Art A dot impact printer prints by causing a current to flow through a solenoid coil to convert electromagnetic energy generated into mechanical energy and causing a print wire to fly. Therefore, the solenoid coil generates heat, and if it is continuously driven, it may even burn out. Therefore, as disclosed in Japanese Patent Laid-Open No. 2-2018, a means for detecting the temperature of a solenoid coil with a thermistor, a means for measuring the print time of a print head, or a means for measuring the number of printed dots, The solenoid drive pulse width, voltage, or cycle is converted to heat control.

FIG. 8 is a block diagram of a printer in which the temperature of the solenoid coil is obtained and controlled by a thermistor therein, and is composed of a thermistor 52 which is a temperature detector built in the print head and an A / D converter 51. The temperature of the print head is detected using a temperature detecting means, and the drive circuit 44 for driving the print head 30 by the microprocessor 41 based on the temperature and the carriage motor drive circuit 45 for driving the carriage motor 70. The control is performed so that at least one of the energization time, the drive voltage, the drive cycle, and the like is variable. Since the thermistor 52 has a very large detection delay, it is desirable to dispose the thermistor 52 adjacent to the most heat generating solenoid. The inventors have obtained through experimentation statistics that the frequency of use of a printing wire when a normal sentence is printed is high, as shown in FIG. 4, and the frequency of use of a specific wire is high. Are arranged adjacent to them so that the temperature of the wire driving solenoid, which is frequently used, can be detected as accurately as possible based on this statistic, as shown in FIGS.

[0004]

By the way, recently, in the printer industry, user-friendliness, particularly operability of paper, has been pursued, and as one of them, a flat bed type printer has been put on the market. FIG. 2 is a diagram for explaining the flatbed type printer, in which 100 is a printer main body and 30 is a print head having a 24-pin structure shown in FIG. The printing paper 100 is conveyed and printed in the direction of arrow A or B set by a paper feed direction changeover switch (not shown). In the printer having such a configuration, when the printing paper conveyance direction is set to the arrow A direction and the printing paper conveyance direction is set to the arrow B direction, as shown in FIGS. The character "AA" printed on 24 is reversed. In this case, the wire usage frequency is shown in Fig. 4.
In the state shown in FIG. 3B, the thermistor 52 is not in the proper detection position in view of the frequency of wire usage.

That is, in such a printer that can print by switching the print paper conveyance direction, even if the same document is printed, the temperature detected by the thermistor 52 varies depending on the print paper conveyance direction, and the printer is used in one direction. Although the temperature of the solenoid coil, which has a high frequency, is properly measured, there is a problem in that it cannot always be said that the proper temperature is measured in the reverse direction.

The present invention has been made in view of the above problems, and an object thereof is to prevent the solenoid coil from being burnt out or to be unnecessary by always performing optimum print control even if the direction of the printed character changes. It is intended to provide a printer having high throughput and preventing a decrease in printing speed.

[0007]

According to a first aspect of the present invention, a temperature detector for detecting a heat generation temperature of a solenoid coil is arranged adjacent to a solenoid coil which is most frequently used in a predetermined printing state, and the temperature detection is performed. When the temperature detected by the container is equal to or higher than the first temperature and equal to or lower than the second temperature, the printing is performed with a reduced printing cycle, and when the temperature is equal to or higher than the second temperature, the printing is stopped. According to a second aspect of the present invention, the first temperature and the second temperature are respectively set according to the orientation of a character to be printed. Further, according to claim 3, a plurality of temperature detectors for detecting the heat generation temperature of the solenoid coil are arranged in the print head, and the temperature from the temperature detector adjacent to the most frequently used solenoid coil that changes depending on the direction of the printed characters is When the temperature is equal to or higher than the first temperature and equal to or lower than the second temperature, the printing cycle is delayed to perform printing, and when the temperature is equal to or higher than the second temperature, the printing is stopped.

[0008]

According to the above configuration of the present invention, appropriate printing control can be performed according to the temperature change of the solenoid coil regardless of the direction of the printed characters.

[0009]

1 is a circuit block diagram showing an embodiment of a print control method of the present invention. The print control unit 40 is a Read Only Me that stores programs and various data.
memory (hereinafter referred to as ROM) 42 and Random A for temporarily storing control data for program operation
access Memory (hereinafter referred to as RAM) 4
3 and dot impact printer 1 with reference to it
Microprocessor 41 for controlling the entire printing operation of 00
A print head drive circuit 44 for driving the print head 30 and a carriage motor drive circuit 45 for driving the carriage motor 70. Temperature detecting means 5
0 is the thermistor 52 which is a temperature detector installed in the print head 30, and A / which detects the resistance value of the thermistor 52.
It is composed of a D converter 51. Reference numeral 60 denotes a paper feeding / discharging direction detecting circuit for detecting the paper feeding / discharging direction, and the print control means 40 is adapted to perform printing control based on information from the paper feeding / discharging direction detecting circuit 60. The arrangement of the thermistor 52 is shown in FIG.
It is arranged adjacent to the solenoid that generates the most heat when the printing paper is conveyed in the direction of arrow A for printing. The operation of the apparatus thus configured will be described below.

When the print control means 40 reads the conveyance in the direction of arrow A in FIG. 2 from the supply / discharge direction detection circuit 60, first, the temperature parameters T1A, T in the direction of arrow A are read from the ROM 42.
2A (T1A <T2A) is stored in the temperature parameter area of the RAM 43, the printing paper is conveyed in the direction of arrow A, and printing is started. At the beginning of the start, the temperature T detected by the thermistor 52 mounted outside the frame of the frequently used solenoid coil
Is lower than T1A (T <T1A), but the temperature T detected by the thermistor 52 gradually rises. And
When T1A is reached (T> T1A), the microprocessor 41
Carriage motor drive circuit 45 to reduce the printing speed
Is controlled, and the temperature rise rate is controlled to be lowered by reducing the number of times the solenoid is driven per unit time.

Despite this control, if the temperature of the solenoid coil rises and the temperature T detected by the thermistor 52 exceeds T2A (T>T2A> T1A), the microprocessor 41
Stops printing and waits until the temperature T detected by the thermistor falls.

Thereafter, the temperature T detected by the thermistor 52 is T
When it becomes 2A or less (T1A <T <T2A), the printing speed is lowered than usual and printing is restarted. When the detected temperature T further decreases and becomes T1A or lower (T <T1A <T2A), the printing speed is returned to normal and printing is performed.

When the paper feeding / discharging direction is the direction of arrow B, the thermistor cannot necessarily detect the temperature suitable for control because the frequently used solenoid coil is replaced. Therefore, when the paper feeding / discharging direction is the arrow B direction, the temperatures T1B and T2B that are equivalent to the temperatures T1A and T2A in the arrow A direction are obtained in advance by experiments, and the temperature parameter in the arrow B direction stored in the ROM 42 is used. By doing so, similar printing control can be performed.

That is, it is possible to always carry out appropriate print control by separately setting the temperatures to be referred to during print control according to the conveyance direction of the print paper.

In the present embodiment, the case has been described in which the printing direction is reversed upside down (rotated by 180 degrees) depending on the paper feeding / discharging direction, but the direction of characters to be printed rotates regardless of the paper feeding / discharging direction. In this case as well, print control similar to that of this embodiment can be performed.

Further, a thermistor is attached to each of the plurality of solenoid coils, a frequently used solenoid coil is determined according to the conveyance direction of the printing paper and the direction of the printed characters, and a thermistor adjacent to the frequently used solenoid coil is used. If the detected temperature is used, the temperature parameter T
It is also possible to control by directly using the values of 1A and T2A.

[0017]

According to the present invention, since appropriate printing control can be performed according to the conveying direction of the printing paper, it is possible to prevent the solenoid coil from being burnt out and to prevent an unnecessary decrease in the printing speed, thereby improving the throughput.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a flood bed type printer.

3 (a) and 3 (b) are views showing that a print character is rotated by 180 ° depending on a conveyance direction of a print sheet.

FIG. 4 is a diagram showing the frequency of use of each wire when a standard foreign document is printed.

FIG. 5 is a diagram showing an arrangement state of temperature detectors.

FIG. 6 is a perspective view showing a structure of a temperature detector and a solenoid coil provided in a print head.

7A is a side view of the print head, and FIG. 7B is a front view.

FIG. 8 is a circuit block diagram of a conventional example.

[Explanation of symbols]

 30 print head 40 print control means 41 microprocessor 42 ROM 43 RAM 44 print head drive circuit 45 carriage motor drive circuit 50 temperature detection means 51 A / D converter 52 thermistor 60 feed / discharge direction setting circuit 70 carriage motor 100 dot impact printer 110 printing paper 201 nose 202 substrate 203 spacer 204 frame 205 heat sink 206 printing wire

Claims (3)

[Claims] 1. A temperature detector for detecting a heat generation temperature of a solenoid coil is disposed adjacent to a solenoid coil most frequently used in a predetermined printing state, and the temperature detected by the temperature detector is equal to or higher than a first temperature. If it is below the second temperature,
A printing control method for a dot impact printer, comprising: printing with a reduced printing cycle, and stopping printing when the temperature is above a second temperature. 2. The print control method for a dot impact printer according to claim 1, wherein the first temperature and the second temperature are respectively set according to the orientation of a character to be printed. 3. A print head is provided with a plurality of temperature detectors for detecting a heat generation temperature of a solenoid coil, and the temperature detected by the temperature detector adjacent to the most frequently used solenoid coil, which changes depending on the direction of the printed characters, is detected. A printing control method for a dot impact printer, wherein when the temperature is higher than or equal to the first temperature and lower than or equal to the second temperature, printing is performed with a reduced printing speed period, and when the temperature is higher than or equal to the second temperature, printing is stopped. ..