JPH02164552A - Controlling method and apparatus for dot impact printing head - Google Patents

Abstract

PURPOSE:To prevent driving units from being overheated and to remarkably improve printing efficiency by comparing the detected quantity of electricity of said driving units with a set value thereby to control time of printing interval for each driving unit. CONSTITUTION:When a transistor Q1 is ON in accordance with a control signal from a CPU, also an analog switch SW1 is turned ON. A current running in an L1 which is a driving unit, namely, a voltage of a resistance R1 is detected by a comparator IC1. Whether the detected voltage is lower than the set value is confirmed. If the detected voltage exceeds the set value, a normal signal is input to the CPU. If the detected voltage is lower than the set value, an overheat signal is input to the CPU. In consequence, the CPU controls dot printing in a normal manner only when signals from each comparator IC1 are all normal signals. If the overheat signal is input at least from one of the comparators IC1, the CPU stops or makes slower dot printing.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to a control method for preventing heating of a drive section of a dot impact print head and its apparatus.

(Prior Art) FIG. 6 is a sectional view showing an example of a general 9×9 dot impact print head.
Only the th printing elements P1 and P5 are shown. A bottle 1 for dot printing is arranged such that one end of the bottle 1 can protrude from the tip of a rad nose 2, and a plate-shaped permanent magnet 3 is fixed to the other end of the bottle 1 so as to form an L-shape. One end of a curved plate spring 4 is superimposed and fixed to the permanent magnet 3, and the other end of the plate spring 4 is clamped and fixed to the inner surface of a cylindrical casing 5. An electromagnet 6 is arranged between the overlapping surface of the permanent magnet 3 and the temporary spring 4 and the rear inner end surface of the housing 5, and one end surface of the 7r1 magnet 6 is close to the overlapping surface, and the electromagnet 6 The other end surface is fixed to the rear inner end surface of the housing 5.

In such a configuration, when no current is applied to the electromagnet 6, as shown in the fifth printing element P5, the overlapping surface of the permanent magnet 3 and the leaf spring 4 is It is adsorbed to one end surface of the r+n stone 6. That is, in this state, one end of the bottle 1 is stored at the tip of the herad nose 2. When a current is passed through the Li3 stone 6 so as to overcome the magnetic force of the permanent magnet 3 and the elastic force of the leaf spring 4, the other end of the temporary spring 4 (the inner surface of the housing 5) sandwiched between.

The mating surfaces of the permanent magnet 3 and the leaf spring 4 with the fixed part) as the fulcrum? ii lil, the bait escapes from one end of the stone 6. Immediately, one end of the bottle 1 protrudes from the tip of the rad nose 2 to perform dot printing. And electric r1
When the current supply to the 11 stones 6 is stopped, the restoring force of the temporary spring 4 causes the overlapping surface of the permanent +a stone 3 and the leaf spring 4 to approach one end surface of the electromagnet 6, and the magnetic force of the permanent magnet 3 causes the overlapping surface to close to one end surface of the electromagnet 6. However, the electric current 6i1 is adsorbed to one end surface of the stone 6 again. That is, one end of the bottle 1 is stored at the tip of the head nose 2. . By repeating the above operations for each printing element, predetermined dot printing can be performed.

By the way, since electric current is frequently passed through the electromagnet 6, which is the drive section of the above-mentioned dot impact print head, heat is likely to be generated. In particular, when high-speed printing or large-volume printing is performed, heat generation becomes intense, and in some cases, there is a risk of burning out the drive unit.

In order to eliminate the above-mentioned drawbacks, a thermal element (such as a thermistor) as a temperature detection means is embedded in the housing of the dot impact print head to detect the temperature, and when the detected temperature exceeds a predetermined temperature, the speed of dot printing is changed. Dot impact printheads have been developed that prevent overheating by reducing temperatures such as °C (e.g. Seikokin's IP-5420). A method has been proposed in which the assumed value is periodically corrected based on the printed symbol and the elapsed printing time, and when the corrected value exceeds a predetermined value, the printing operation of the dot impact print head is restricted (particularly Kaisho 61-8327
(See Publication No. 5).

(Problems to be Solved by the Invention) In the Drummy Impact Print Head described above, in which a heat-sensitive element is embedded in the housing, the heat generated in the drive unit is difficult to transfer due to the large heat capacity of the housing. There is a time delay in detecting the actual temperature of the Therefore, there is a drawback that the drive section is burnt out before overheating of the drive section is detected and the speed of printing operation is reduced. In addition, the method of calculating the temperature of the dot impact print head described above is based on fluctuations in the voltage applied to the drive unit, variations in the flow of cooling air from the fan to turn on the dot impact print head, etc. , an error is likely to occur between the actual temperature of the drive unit and the temperature calculated by calculation of 31.

Therefore, even if the calculated temperature does not exceed a predetermined value, the drive section may be burnt out.

This invention was made due to the circumstances mentioned above,
SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for controlling a dot impact print head that can detect temperature changes in a drive unit in a short time to control dot printing operations and prevent overheating of the drive unit. It is in.

Structure of the Invention; (Means for Solving the Problems) The present invention is directed to a control method for preventing overheating of the drive unit of a dot impact print head, and the above object of the invention is to By detecting the amount of electricity in each drive section of the dot impact print head during operation, and comparing the detected amount of electricity with a preset value to control the printing interval time of each drive section, Alternatively, the quantity of electricity of each driving part of the dot impact print head in the dot printing operation is detected, and each detected quantity of electricity is compared with a preset value, and at least one of the detected quantities of electricity is determined as set by the setting value. If it is lower than this value, this is achieved by stopping or slowing down the dot printing operation.

The control device also includes a detection section that detects the amount of electricity of each drive section of the dot impact print head during dot printing operation, and a value that is set in advance and the amount of electricity detected from each detection section. It is equipped with a comparison section that compares each and outputs a symbol, and a control section that controls the printing interval port of the corresponding drive section according to the signal from each comparison section, or the dot impact during dot printing operation. a detection section that detects the amount of electricity of each drive gB of the print head; a comparison section that compares the amount of electricity detected from each detection section with a preset value and outputs No. 43; At least one of the comparison units outputs the signal output when the amount is lower than the set value.
This is achieved by comprising a control section that stops or decelerates the dot printing operation when an input is received from the user.

(Function) The dot impact print head control method and apparatus of the present invention utilize the fact that the resistance of the drive section increases with temperature rise, and the resistance of the drive section can be adjusted by detecting the current flowing through the drive section. The dot printing operation is controlled to prevent the drive unit from overheating by determining changes in the temperature of the drive unit, that is, changes in the temperature of the drive unit.

(Example) FIG. 1 is a circuit diagram showing an example of a control device for a dot impact print head of the present invention, in which the current flowing through the coil 1.1, which is the drive section, is turned on and off by turning on and off the transistor ql. At the same time, the analog switch SWI is turned on and off. That is, transistor Q
1 is on, the analog switch SWI is also on, and the current flowing through the coil 1.1 and the voltage across the resistor n1 are detected by the comparator ICI. Then, the detected voltage is compared with a preset value, and when the detected voltage is higher than the set value, a normal signal is sent, and when the detected voltage is lower than the set value, an overheating signal is sent to the cPU. It has become. Such a circuit is provided for each coil, and each coil is driven by R by CPt1.
1! It is now controlled by J.

In such a configuration, an example of its operation will be explained with reference to the flowchart in Figure i2. When the transistor Ql is on according to the control signal from CPjl, current flows through the coil L1 (step 51). Normally, the resistance of the coil L1 varies depending on the temperature. y increases, so the current flowing through the coil Ll decreases. For example, FIG. 3(a) shows the transistor Ql
There is a waveform diagram showing an example of VCE of transistor Ql.
When the coil 141 is cooled, the current flowing through the coil L1 (in this example, resistance 1 (replaced with a voltage of 1)) is lt&r as shown in FIG.
(1.7V), but when the coil Ll is overheated, the value becomes low (1.4V) as shown in FIG. 2(c). Comparator IC1 is the voltage across the resistor (flowing to coil Ll?
jt flow) is detected (Step S2), and it is checked whether the detected voltage has become lower than a set value (Step S3). This set value is, for example, the limit voltage (a value at which the coil Ll can be normally driven) determined based on the values shown in Figure 3 (1)) (C), and is set in the comparator in advance. Then, the detection voltage is set (if it is higher than j'f, the normal signal is sent to the cPU
manually, and if the detected voltage is lower than the set value,
Input the heat signal to cru. If the manually inputted signal is a normal signal, the CP 11 controls the coil that outputs the normal signal using the normal printing interval time (step S4);
If the input signal is an overheating signal, the coil that outputs the overheating signal is controlled for a longer time than the normal printing interval time (step S5). Then, the process returns to step S2 and the above-described operations are repeated until printing is completed.

FIG. 4 is a circuit diagram showing another example of a control device for a dot impact print head according to the present invention, corresponding to FIG. 1, and the same components are given the same reference numerals and the explanation thereof will be omitted. In this case, the output from each comparator is directly connected and input to the CPU.

In such a configuration, an example of its operation will be explained with reference to the flowchart of FIG. 5. In accordance with a control signal from CPt1, current flows through coil L1 when transistor Q is on (step 511). Comparator ICI detects the voltage across resistor 11 (current flowing through coil L1).Step 5
12) Check whether the detected voltage has become lower than the set value (step 513). If the detected voltage is higher than the set value, a normal signal is input to CPII, and if the detected voltage is lower than the set value, an overheating signal is input to (:Ill+). Ild control of the normal dot printing operation is performed only when all the signals are normal (step 514), and when an overheating signal is input from at least one of the comparators, the dot printing operation is stopped or decelerated (step 514). 515).And step 5
Returning to step 12, the above-described operation is repeated until printing is completed.

Effects of the invention: As described above, according to the dot impact print head control method and device of the present invention, overheating of the drive unit 5) can be prevented, and continuous operation can be achieved when performing high-speed printing or large-volume printing. As a result, maintenance becomes easy, printing processing time can be shortened, and printing efficiency can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a control device for a dot impact print head according to the present invention; FIG. FIG. 4 is a circuit diagram showing another example of the control device for the dot impact print head of the present invention, FIG. 5 is a flowchart explaining an example of its operation, and FIG. 1 is a sectional view showing an example of a typical dot inbound print head. l... bottle, 2... head nose, 3... permanent 1
, 1 stone, 4... leaf spring, 5... housing, 6... TL
Magnet, ICI... Comparator, SWI... Analog switch, Ll... Coil, Old... Resistor, ■... Transistor. Voltage

Claims (1)

[Scope of Claims] 1. Detect the amount of electricity of each drive section of the dot impact print head during dot printing operation, compare each detected amount of electricity with a preset value, A method for controlling a dot impact print head, characterized in that the print interval time of the dot impact print head is controlled. 2. A detection unit that detects the amount of electricity of each drive unit of the dot impact print head during dot printing operation;
A comparison section that compares the amount of electricity detected from each detection section with a preset value and outputs a signal, and a control section that controls the printing interval time of the corresponding drive section according to the signal from each comparison section. A dot impact print head control device comprising: 3. Detect the amount of electricity of each drive unit of the dot impact print head during dot printing operation, compare each detected amount of electricity with a preset value, and determine whether at least one of the detected amounts of electricity is A method for controlling a dot impact print head, characterized in that when the value is lower than the set value, the dot printing operation is stopped or decelerated. 4. A detection unit that detects the amount of electricity of each drive unit of the dot impact print head during dot printing operation;
a comparison section that compares the detected amount of electricity from each detection section with a preset value and outputs a signal; and a comparison section that compares the signal that is output when the detected amount of electricity is lower than the set value. A control device for a dot impact print head, comprising: a control section that stops or decelerates the dot printing operation when an input is received from at least one of the sections.