JPH0593838U - Printer - Google Patents

Abstract

(57) [Summary] [Purpose] Adjust the value of the voltage applied to the thermal head and the application time without using a measuring instrument. [Structure] A plurality of series circuits of a heating resistor 2 and a normally-open switching element 4 are connected in parallel to each other, and the parallel circuit is connected to a power source 8 via a normally-open switching element 6 to provide a normally-open switching element 4 Connected to a predetermined one of them
Of the normally open switching element 6 while supplying the energizing signal of
Is provided with a control means 10 for supplying a second energizing signal with a certain time width, and the voltage of the power source 8 or the time width of the second energizing signal, which is a change factor of the heat generation amount of the resistor 2, is manually changed. The deviation calculating means 104 calculates the deviation between the change factor detected by the change factor detecting means 12 and the reference value stored in the storing means 102, and the deviation is displayed on the display means 106. indicate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thermal printer that presses a heat-generating resistor on a label coated with a heat-sensitive material so that the pressed portion is colored to perform printing.

[0002]

[Prior Art]

Generally, a plurality of heating resistors are provided, together with a switching element connected in series for passing a current through them and a shift register for selecting one of these switching elements to be closed. It constitutes a thermal head. The resistance value of the heat-generating resistor of such a thermal head varies from thermal head to thermal head. In order to print satisfactorily with such a thermal head, it is necessary for the heat-generating resistor to generate heat of a predetermined heat generation amount Q. The heat generation amount Q is represented by Q = 0.24E ² · T / R. Here, E is the voltage applied across the heating resistor, R is the resistance value of the heating resistor, and T is the application time of the applied voltage.

[0003]

[Problems to be solved by the device]

 As is clear from the above equation, R of the heating resistor cannot be changed. Therefore, if the application time is constant, the applied voltage E must be accurately adjusted in order to obtain the predetermined heat generation amount Q. On the contrary, when the applied voltage E is constant, the application time T must be adjusted accurately in order to obtain the predetermined heat generation amount Q. Moreover, if these adjustments are neglected and the heat generating resistor is caused to generate heat of a predetermined heat generation amount Q or more, the life of the thermal head will be shortened.

Since the adjustment of E or T is very important in this way, it is repeated many times during manufacturing of the printing apparatus, such as shipping inspection, regular inspection and defective head replacement. However, there has been a problem that the conventional E adjustment always requires a measuring device such as a voltmeter, and smooth adjustment cannot be performed.

[0005]

[Means for Solving the Problems]

 This invention solves the above problems, and as shown in FIG. 1, a plurality of series circuits of a heating resistor 2 and a first normally-open switching element 4 are connected in parallel with each other, This parallel circuit is connected to the power supply 8 via the second normally open switching element 6 and connected to a predetermined one of the first normally open switching elements 4 to supply the first energizing signal and the second In a printing apparatus in which the normally-open switching element 6 is provided with the control means 10 for supplying the second energizing signal with a certain time width, the voltage of the power source 8 which is a change factor of the heat generation amount of the heating resistor 2 or A variable means 108 for manually changing the time width of the second energizing signal, a detecting means 12 for the change factor, and a storage means for storing the reference value of the change factor detected by the detecting means 12. 102, and the detection means 12 detected The factor and the deviation calculating unit 104 for calculating a deviation between the reference value, and display means 106 for displaying the deviation is to provided.

[0006]

[Action]

 According to the present invention, the voltage of the power supply 8 or the time width of the second energizing signal is detected by the detecting means 12, and the deviation between this and the reference value of the storing means 102 is calculated by the deviation calculating means 104 and displayed. It is displayed on the means 106. Therefore, the voltage of the power supply 8 or the time width of the second energizing signal can be set to the reference value by adjusting the variable means 108 until the display of this deviation becomes zero.

[0007]

【Example】

 Hereinafter, the present invention will be described in detail based on two embodiments implemented in the label printer shown in FIGS. A first embodiment is shown in FIGS. 2 and 3. As shown in FIG. 2, this label printer has a micro computer including a CPU 14, a ROM 16 and a RAM 18. A weighing signal is supplied from the weighing unit 20 to the CPU 14. This weighing signal represents the weight of the article to be weighed on the tray 22 of the weighing unit 20. The unit price signal is also supplied from the setting unit 24 to the CPU 14. The unit price signal represents the price (unit price) of the article to be weighed on the platen 22 per unit weight. While exchanging data with the RAM 18 according to the program written in the ROM 16, the CPU 14 calculates the price of the article to be weighed on the platen 22 based on the weighing signal and the unit price signal, and the display unit 26 displays the weight, unit price, In addition to displaying the price, a print signal composed of a clock signal, a print data signal and an enable signal is supplied to the shift register 28 of the thermal head. Since the programs for these operations are known, the disclosure of the flowchart is omitted.

The thermal head has heat generating resistors 30-1 to 30-n, and these heat generating resistors 30-1 to 30-n are emitter-collectors of NPN switching transistors 32-1 to 32-n. The series circuits are connected in series to each other, and these series circuits are connected in parallel to each other and also connected between the variable voltage section 36 and the reference potential point via the PNP switching transistor 34. Reference numeral 38 is a variable resistor for varying the voltage. The bases of the switching transistors 32-1 to 32-n are connected to the respective stages of the shift register 28. Of course, the shift register 28 is composed of n stages. The base of the switching transistor 34 is connected to the CPU 14. Reference numerals 40, 40 ... 42, 42 ... Show bias resistors for the switching transistors 32-1 to 32-n.

The CPU 14 first sends a print data signal of one line sentence to be printed on a label to the shift register 28 in series using a clock signal. For example, when the heat generating resistors 30-1 and 30-2 are caused to generate heat, n print data signals of "000 ... 011" are sent to the shift register 28 by the clock signal, and the first and second shift register 28 The output of the second stage is set to H level.

Next, the CPU 14 sends an enable signal to supply a level signal to the shift register 28 at the bases of the transistors 32-1 and 32-2. Then, the CPU 14 supplies an L-level signal to the base of the transistor 34 to cause the transistors 34, 32-1, 32-2 to conduct, and the heat generating resistors 30-1, 30-2 from the power supply unit 36. An electric current is supplied to heat them. Then, after a certain time has elapsed, the CPU 14 changes the L level signal supplied to the transistor 34 into an H level signal, and stops the current supply to the heating resistors 30-1 and 30-2. Then, the label is fed by one line, and the second and subsequent lines are printed in the same manner as described above. Since the program for this operation is also known, the disclosure of the flowchart is omitted.

In addition to these components, in this embodiment, a voltage detection unit 48 for detecting the magnitude of the voltage of the voltage unit 36 is provided. That is, the voltage of the voltage unit 36 is input to the voltage detection unit 48 via the protection resistors 50 and 52. The voltage detector 48 is composed of, for example, an A / D converter, and the digital signal VD thereof is input to the CPU 14.

The CPU 14 calculates the difference between the voltage VR and the voltage VR required to heat the heating resistors 30-1 to 30-n written in the RAM 18 in advance with a predetermined amount of heat, and calculates this difference. It is displayed on the display unit 26. Then, the variable resistor 38 of the variable voltage section 36 is adjusted so that this difference becomes zero. Reference numeral 54 is a switch for switching between such an adjusting operation and the above-described printing operation.

FIG. 3 shows a flow chart of the program of the adjusting operation. First, in step 56, it is determined whether the switch 54 is on. If it is not turned on, the routine proceeds to the print routine for executing the above print operation. If it is on, the process proceeds to step 58, where the reference voltage VR is read. Next, in step 60, the voltage VD is read, and in step 62, VD-VR is subtracted to obtain the subtraction value S.

Then, in step 64, the subtraction value S is displayed on the display unit 26. Next, at step 66, it is judged if the switch 54 is off. If it is off, stop it. If it is not off, return to step 60, and repeat steps 60 to 66 until it is off. Therefore, the subtraction value S is continuously displayed on the display unit 26 until it is turned off. During this time, the variable resistor 38 is adjusted so that the subtraction value S becomes zero. As a result, it is possible to apply a voltage for causing the heating resistors 30-1 to 30-n to generate heat with a predetermined heating value Q.

A second embodiment is shown in FIGS. 4 and 5. In this embodiment, the voltage E of the voltage section 36a is kept constant in order to obtain the predetermined heat generation amount Q, and the time width for applying this voltage E can be adjusted. Therefore, a pulse generator 68 is provided as shown in FIG. That is, when the pulse generator 68 receives the trigger pulse from the CPU 14, the pulse generator 68 supplies the L-level output to the transistor 34 for a period of time width determined by the value of the variable resistor 69 attached to the pulse generator 68.

The time width TD during which the pulse generation unit 68 is generating the L level output is detected by the pulse width detection unit 70 and supplied to the CPU 14. The CPU 14 calculates the difference between the reference time width TR read from the RAM 18 and the detected time width TD, and displays the subtraction value S on the display unit 26. The reference time width TR is determined by the predetermined heat generation amount Q and the voltage E. Based on the displayed subtraction value S, the variable resistor 69 is adjusted so that it becomes zero. At this time, the transistor 34 conducts, but the CPU 14 does not supply the clock signal, the print data, and the enable signal to the shift register 28, so that the switching transistors 32-1 to 32-n do not conduct. Therefore, the heat generating resistors 30-1 to 30-n do not generate heat and printing is not performed.

FIG. 5 shows a flowchart of this adjusting operation. First, at step 72, it is judged if the switch 54 is on. If it is not ON, the routine proceeds to the printing routine, and if it is ON, the reference pulse width TR is read in step 74. Next, in step 76, a trigger pulse is supplied to the pulse generator 68. In step 78, the time width TD detected by the pulse width detection unit 70 is read. In step 80, TD-TR is subtracted, and the subtracted value S is displayed on the display unit 26 in step 62. Next, in step 84, it is determined whether or not the switch 54 is off. If it is off, the switch 54 is stopped. If it is not off, the retrigger command signal is supplied from the setting section 24 in step 86. Whether or not it is supplied, the process returns to step 82 and steps 82 to 86 are repeated. During this time, the variable resistor 69 is adjusted. Then, when the adjustment is completed, the retrigger command signal is supplied, the process returns from step 86 to step 76, and the subsequent steps are executed. At this time, if the display value is zero, the switch 54 is turned off and stopped. If it is not zero, the variable resistor 69 is adjusted again. Hereinafter, this is repeated until it becomes zero.

In the above embodiment, the difference between the detection voltage or the detection pulse width and the reference voltage or the reference pulse width is displayed. However, in addition to displaying the difference between the detection voltage and the reference voltage, the detection pulse width and the reference pulse width are displayed. The difference from the pulse width may also be displayed.

[0019]

[Effect of the device]

 As described above, according to the present invention, the voltage detection unit or the pulse width detection unit is provided, the detected voltage or pulse width is compared with the reference value, the difference is displayed on the display unit, and the displayed difference is displayed. Since the voltage or the pulse width is adjusted until the voltage becomes zero, that is, the voltage or the pulse width is adjusted to be equal to the reference value, the adjustment work efficiency can be improved.

For example, when a signal from a signal source is displayed on a meter or the like, a variable signal source is provided in addition to the signal of this signal source so that the displayed value becomes, for example, zero. There is one in which signals are added by an adder, the added value is displayed on a meter, and the signal of the variable signal source is changed so that the displayed value on the meter becomes zero (Japanese Patent Laid-Open No. 56-150359). However, this requires a variable signal source for adjustment in addition to the original signal source, which complicates the configuration. On the other hand, in the present invention, the voltage source for comparison or the pulse generator itself is made variable instead of separately providing a voltage source for adjustment, so that the configuration is simple.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a printing apparatus according to the present invention.

FIG. 2 is a block diagram of a first embodiment of the present invention.

FIG. 3 is a flowchart of the first embodiment.

FIG. 4 is a block diagram of the second embodiment.

FIG. 5 is a flowchart of the second embodiment.

[Explanation of symbols]

 2 Heat generating resistor 4 First switching element 6 Second switching element 8 DC power supply 10 Control section 12 Detection section 102 Storage means 104 Deviation calculation means 106 Display means 108 Variable means

Claims (1)

[Scope of utility model registration request] 1. A plurality of series circuits of a heating resistor and a first normally open switching element are connected in parallel with each other, and the parallel circuit is connected to a power source through a second normally open switching element, Control means connected to a predetermined one of the first normally open switching elements to supply the first energizing signal and to the second normally open switching element to supply the second energizing signal with a certain time width. In the printing device provided, a varying means for manually varying the voltage of the power source or the time width of the second energizing signal, which is a variation factor of the heat generation amount of the heating resistor, and a variation factor detecting means. A storage means for storing the reference value of the change factor detected by the detection means, a deviation calculation means for calculating a deviation between the change factor detected by the detection means and the reference value, and the deviation Display means for displaying Printing device.