JPS6183063A - Thermal head manufacturing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application J] The present invention relates to an apparatus for manufacturing a thermal head used in a main binding C facsimile machine or a printer.

[Conventional technology]

Thermal heads, which do not require development or fixing, are noiseless, maintenance-free, and have high reliability, are becoming more popular along with thermal recording paper. In thermal recording, a recording current is applied to a resistor provided on a substrate, and the Joule heat generated by the current flowing through the resistor is used to color the thermal paper in contact with the resistor, or to color the ink on thermal transfer paper. melt the layers,
This is a technique for recording by applying recording signal information to the transfer paper.

A general structural diagram of the thermal head is shown in FIG. 91.

The thermal head has an insulating substrate (1) and A/, Au-
A heating element is constituted by a lead part (21) made of a good electrically conductive material such as Cu using a film-forming technique, and a film-like element resistor (3) connected to both ends of the lead part (21).

As the material of the insulating substrate (1), an alumina ceramic substrate or an alumina ceramic substrate with a glaze layer is often used. In the case of a thin film type, the material of the element resistor (3) is Ta2N, Ta-5ioz + Ta-5i,
A material such as Ni-CuTi203 is used.

In the case of a thick film method, a noble metal oxide such as Rug O+ P to is mixed with a glass material, applied and sintered.

Although not shown, after forming the element resistor (3), a glass film for protecting it is fired.

When a constant voltage is applied to both ends of the lead portion of this thermal head for a certain period of time, heat is generated in the resistor portion due to Joule heat. This heat is absorbed by the A of the recording device configured as shown in Figure 10.
The light is transmitted to the thermal paper (5) at a certain portion, and the thermal paper (5) develops color and is printed on its surface. In addition, in Figure 1O, the 9th
The same symbols as in the figure indicate corresponding parts. P indicates the pressing direction of the roll (4).

Generally, in a thermal head for facsimile, for example, about 2000 resistors are independently arranged in parallel as heating resistors per head. These heating resistors have a surface temperature of 250°C to 60°C due to their Joule heat.
The thermal head is heated to about 0° C., and the applied energy equivalent to reaching this temperature is about 0.2 mJ (joule) to 2 mJ, depending on the resolution of each thermal head.

Conventionally, there have been three types of thermal heads: a thick film type, a thin film type, and a semiconductor type, depending on the manufacturing process and material of the resistor. For the thick film type, a desired pattern is formed in advance on a screen or photon cyst film using a paste-like resistive material, and the resistive material is printed or embedded using screen printing technology and is fired as a post-process to generate heat. A resistor is formed. For the thin film type, a tantalum-based material is mainly vapor-deposited or sputtered to form a basic pattern that will serve as a resistor, and then photoetched to form an independent resistor with a desired pattern. In the semiconductor type, for example, resistance is diffused into a part of a silicon base material to form a resistor, and heat generated at the P-N junction surface is utilized, and almost the same means as in the semiconductor manufacturing process is used.

Of the eight manufacturing methods to date, the ones that have been put into practical use are the thick film type and the thin film type. Incidentally, the thin film type has the great advantage that although the manufacturing process is extensive, there is little variation in the resistance value of the heating resistor and a fine pattern can be formed. On the other hand, the thick film type can be manufactured at low cost through a relatively short manufacturing process, but it has the serious drawback of large variations in the resistance value of the heating resistor. Thermosensitive recording is determined by the resistance value of a resistor and utilizes the generated Joule heat, so variations in resistance value naturally cause density unevenness in the printed image quality.

FIG. 11 shows an example of resistance values R1, R2, . . . , Rn of each element resistor constituting the thermal head.

Normally, the resistance value variation of thin film type is uniform within ±6% to ±16%, while that of thick film type is uniform between ±15% to ±8%.
The reason why it has become popular even though it has a variable temperature of 096°C and is inferior to the thin film type is that it has the great advantages of low cost and good stability represented by overload power and wear resistance. This is because there is.

Recently, it has become possible to form fine patterns with thick film types as well as with thin film types. For example, in forming an IK pattern, the printed film thickness has conventionally been required to be 8 μm or more, but it can also be constructed with a conductor film thickness of aoooX or less. This advantage is due to the fact that the etching factor during photoetching is about the same as that of the thin film type, ie, almost zero, compared to the conventional etching factor of 20I1m. - In order to improve the variation in resistance value of blade thick film type, in addition to the improvement of conventional screen printing technology such as improvement of mesh screen and metal mask screen, for example, the thickness improvement described in Japanese Patent Publication No. 59-22675 Photoetching of a film resistor, method of embedding a thick film resistor as described in Japanese Patent Publication No. 57-18506 into a photoresist (turn method, method of embedding a thick film resistor as described in Japanese Patent Publication No. 54-99448) Furthermore, there is a method in which a thick film resistor is printed on a thin film conductor, as described in Japanese Patent No. 55-47597.

These attempts are to make the shape of the heating resistor uniform and to improve the variation in resistance value caused by this effect.

Further, progress has been made in improving thick film resistor materials.

Thick film resistance material C is, for example, JP-A-58-964
Ruthenium oxide, high melting point frit glass, zirconium oxide, etc. described in No. 4 and JP-A No. 58-9548 are suitable. However, these improvements were made mainly to maintain reliability as a °C1 thick film type thermal head, and did not improve the variation in heating resistance value. However, if the shape of a thick film resistor is geometrically arranged to be the same as that of a thin film resistor, there is a question as to whether the variation in resistance value will really be the same as that of a thin film resistor. Logically speaking, the resistance value of a resistor is expressed by the following formula.

R= -・ □ (QI lt where p: resistivity of resistor (Ω-CM) t: length of resistor CCIII") W: width of resistor CCIB> t: thickness of resistor (C1ll) Screen-printed heating resistors usually have slight variations in the length (l), width (W), and thickness (1) of the resistor, but this will ultimately become a problem. A thick film resistive material is basically a ruthenium oxide glass frit that maintains a certain particle size.

This is the variation in the resistivity itself of the resistor caused by the difference in the degree of bonding that occurs during firing of zirconium oxide, etc., and the resulting variation in the resistance value.

This problem cannot be solved by strict screening and firing conditions in the thick a'Is manufacturing process, and even by improvements in the pre-process and post-process of manufacturing the heating resistor.

This is because the particle size of ruthenium oxide etc. is
As stated in No. 4, the Me-Is-Me value at the contact interface with the ruthenium oxide glass frit is important in determining the resistance value of a thick film resistor. This is because the cause is ultimately due to the inhomogeneous bonding state of (metal-insulator metal). Basically, the thick film resistance material has a firing temperature of 5 atmospheres,
The reason why the resistance value changes significantly despite the firing speed and the same material is presumed to be due to the change in the Me-Is-Me bonding state.

Therefore, thick film resistive materials such as ruthenium oxide and glass frit with finer grain sizes have recently become commercially available. However, the desired effect was not achieved.

From the following, it can be seen that unless the variation in thick film resistance due to non-uniformity of the contact interface is corrected, the variation in resistance value will not be improved. In order to improve the variation in resistors, C has traditionally used laser trimming methods etc. to adjust the C1 resistance value, etc. It is implemented on X film circuit boards, thin film circuit boards, etc. Also, JP-A-58
In the liquid jet recording head described in JP-A-7160 or JP-A-58-7860, the thin film resistive element is laser trimmed and the resistance value is adjusted to match the air-thermal conversion characteristics.
There is.

[Problem that the invention seeks to solve]

All conventional methods for improving the variation in resistance values of thick film resistors have been insufficient. Chemical trimming methods, which are susceptible to impact, cannot be used because of the mechanical vibration caused by the movement of a rotating roller located at the sleeve of the heating resistor that presses against the thermal paper. In addition, since a uniform temperature distribution is required, the shape of the heating resistor is also an important factor, so mechanical trimming methods such as laser, diamond cutting, and sandblasting are not effective due to changes in shape. It could not be used because it would worsen the condition.

An object of the present invention is to provide an apparatus for manufacturing a heat generating resistor of a thick film thermal head by changing its shape (and its resistance (tit)) without changing its shape.

[Means for solving problems]

In the present invention, a voltage pulse is applied to a heating resistor of a thermal head by a pulse generating circuit to reduce the resistance value and the variation in resistance. A resistance meter is installed to measure the resistance value of the heating resistor.

[For production]

In this invention, by utilizing the fact that the resistance value of the °C heating resistor decreases by applying a voltage pulse, it is possible to significantly reduce the variation in the °C1 resistance value. As a result, density unevenness in the print quality of the thermal head can be significantly reduced.

[Embodiments of the invention]

In the present invention, after the main production process, a process is performed to reduce the resistance value of the heating resistor to a certain extent.

That is, after forming a heating resistor, a lead wire, and a protective glass film on a substrate, a process of reducing the resistance value is performed using the apparatus of the present invention.

FIG. 1 is a diagram showing the principle of a method of reducing the resistance value of a heating resistor to eliminate C variation.

This invention utilizes the phenomenon that when a voltage is applied to a thick film resistor, the resistance value decreases. This phenomenon is MIM
It is also thought that this is because the insulator (In5ulator) of the thick film resistor having a (Metal-Insulator-Metal) structure causes a breakthrough due to voltage.

In any case, it is certain that the physical properties of the resistor change with the application of voltage.

FIG. 1 shows the case where the resistance value of the heating resistor, which is the initial resistance value R1, R2*R3, is adjusted to R, °C.

First, the resistance value of each heating resistor is measured and compared with the target resistance value R. No voltage pulse is applied at °C to heating resistors with resistance values lower than R4 such as R4, voltage pulses are applied to heating resistors with resistance values R1* R2 and R3 greater than Ro. .

First, a voltage pulse whose peak value is initially set to Vo is applied to reduce the C resistance value. Measure the resistance value after the decrease, e
If the voltage is R8 or higher, a voltage pulse with a peak value of v0+ΔV is applied. Thereafter, the resistance value is measured, and if the resistance value is R6 or higher, a voltage pulse having a peak value of v0+2ΔV is applied. In this way, the resistance value is gradually worn away while gradually increasing the peak value of the applied voltage pulse until the resistance value becomes R or less. If the resistance value becomes less than or equal to Ro, the adjustment ends there. In this way, the resistance value of the heating element C is set to R,
Align within the following range. Reduce the variation in resistance value (
Since that is the purpose of the present invention, it is not only necessary that the resistance value be less than R8, but it is required that it be within a certain range of less than Ro. Therefore, the resistance value is gradually decreased to C, and stopped when it becomes less than R (1). It is a diagram showing the distribution of resistance values of heating resistors in the case of implementation.Several heating resistors are grouped into − groups, and the maximum value is marked with a white circle, the average value is marked with a black circle, and the minimum value is marked with an X. It is shown by C.

If it is not carried out, the variation in resistance value will be very large, but
It can be seen that there is almost no variation when carried out (Natsu°C).

FIG. 4 is a configuration diagram showing an example of the apparatus of the present invention. FIG. 6 is a waveform diagram of the main signals in FIG. 4.

(6) is a probing device that presses a probe against the thermal head (7) to be adjusted; (8) is a relay network that guides the applied voltage pulse to the desired heating resistor; (9)
is a switch that switches between voltage application and resistance measurement, αq is a pulse generation circuit that generates an adjusted voltage pulse, aυ is a resistance meter, (6) is a calculation section, a3 is its input/output section, α脣 is a central processing unit ( (hereinafter referred to as a CPU), Rabbit is a memory, M is a keyboard, and αη is a printer.

Regarding the procedure for reducing the resistance value by the device of the present invention,
explain.

A setting signal for the peak value Vs of the applied voltage and a setting signal for the number n of pulses included in one voltage application are given from the calculation section.
There is C. Here, measure the resistance value and set the target resistance value R6.
For heating resistors with larger resistance values, the following process is carried out. Upon receiving the voltage application start signal 5TART from the calculation unit @, the pulse generation circuit α (e 1.t
An ENABLE prohibition signal is sent back to the calculation unit. Further, the switch (9) is switched to the pulse generating circuit α0 side.
During the period when the ENABLE prohibition signal is output, the wave height (@
Changes in Vs and generation of the 5TART signal are prohibited. This is because the peak value Vs should not be changed while the voltage pulse is being applied, and the start signal 5TART for applying the next voltage pulse should not be changed until the application of the current voltage pulse is finished.
This is because it should not be uttered. 5 When a certain period of time TI passes after the TART signal is applied, the pulse generation circuit α0 sends n pulses with a peak value of Vs to the heating resistor of the Ctherma I head (7) through a switch (9) and a relay network (8). to be applied. After the end of the application of the pulse voltage and the lapse of time T2, the switch (9) is switched to the resistance meter (6) side. After another 13 hours, the ENABLE inhibit signal is released and the next voltage can be applied to I/C. Resistance (direct measurement) is performed at the station at time T3, and the measurement result is sent to the calculation section (b).
sent to. On the calculation unit side, CPU Q4 compares the measured value with the previous measured value. Then, the measured value of °C1@ times is set as a standard, and if it is not within a certain range, it is determined that there is a welding defect. There are various ways to set the certain range, but the simplest method is to compare the previous measured value to see if it is higher than C. The following method will be described as an example.

If a higher value than the previous measurement is obtained, then C
The PU (141) does not use this measurement value, but sends a reprobe signal to the probing device (6) to release the probe from the thermal head (7) to be measured and recontact it. The value is remeasured. As can be seen from Figure 1, it is impossible for the C resistance value to increase due to the application of the voltage pulse, and if it does increase, it is due to the tip ( This is because it is thought that this is due to poor contact of the probe.

In this case, if the probe contacts the same place again, there is a possibility that the probe will contact again. Therefore, re-contact is not done at the previous point, but at a point a little further away.
conduct. The probe makes contact at a point called a pad provided at the end of the lead wire, but makes contact again at a slightly distant location within the same pad.

If the resistance measurement value is lower than the previous measurement value, the CPU α◆ adopts this measurement value and compares it with the C adjustment target position.

If it reaches below RO and does not reach C, CPU
After the I and E prohibition signals are released, the set value Vs of the peak value of the voltage pulse to be applied is increased by ΔV and given to the °C pulse generation circuit uQ, and then the start signal 5TART for applying the next voltage pulse is sent. Occur.

In this way, while increasing the peak value of the applied voltage pulse gradually at 1°C, the resistance value of the heating resistor is decreased by 1 degree. When the resistance value becomes equal to or less than the adjustment target value R, the adjustment of the resistance value of the heating resistor is completed.

Time limit T1. The reason why T3 is provided is to avoid the influence of chattering in the switching connection circuit consisting of switch (9) and relay m (8). Before the switch (9) is completely switched to select the pulse generation circuit aQ side and the relay network (8) selects the - heating resistor, the pulse generation 1g is selected.
Even if a voltage pulse is generated from path 00°C, the pulse is not applied to the thermal head (7).

Also, after applying the voltage pulse, the switch (9) switches the resistance meter aη
Measure the resistance before switching completely to the C side.
cannot be measured accurately. The reason why the time limit T2 is provided is to prohibit switching of the switch (9) during that time since it takes time for the voltage pulse to completely disappear. The voltage pulse to be applied can be applied as a single pulse in °C, but it is easier to control it if it is applied as a group of pulses consisting of several (I) pulses.

The energy of the voltage pulse is determined by the peak value and the pulse width Δt in °C, but if this becomes too large, the heating resistor will be destroyed. Therefore, if the energy of the voltage pulse exceeds a certain level and there is a risk of destroying the C heating resistor, the width of the C pulse must be adjusted to decrease in accordance with the peak value of the voltage pulse. Rather than adjusting the pulse width of a single pulse, the width Δt of each pulse in a pulse group is constant and the ratio Δt/T of the pulse period 'r and the pulse width Δt is varied. It is easier to adjust C to below a value that does not destroy the heating resistor as the high value changes.Alternatively, it is easier to adjust C to a value that does not destroy the heating resistor.
Then, the number n of pulses constituting the C pulse group may be changed in accordance with changes in the peak value. If the energy of the voltage pulse is sufficiently small, either a single pulse or a group of pulses may be applied.

If the peak value of the applied voltage pulse is low, the phenomenon that the resistance value decreases is not observed. Therefore, it is better to start applying the first voltage pulse from a suitable peak value where a decrease in the resistance value can be expected. This is advantageous. VQ in FIG. 1 indicates the peak value of the first applied voltage pulse.

The adjustment target resistance value & the number of pulses n are changed using the keyboard 4'C. The adjusted resistance value and the calculation results of the CPU α are outputted to the printer Q71.

FIG. 6 is a flowchart of a method for adjusting the resistance value of a heating resistor using the apparatus shown in FIG. 4.

In step 4, pulse conditions such as the peak value Vs and the number of pulses n are initialized. Next, in step @, probing to the thermal head (7) by the probing device (6) and switching of the relay network (8) are performed.

Next, in step..., the resistance value is measured. The measured value is compared with the target value R using a step check, and if it is smaller than RO, no voltage pulse is applied. When the resistance value is greater than Ro, in steps (to) and (to), n pulse trains having a set peak value are applied, and the resistance value is measured. The current measurement value is compared with the previous measurement value in step (good), and if it is larger than the previous measurement value, probing is performed again in step (c). 11'tIIP! If it is smaller than the measured resistance value I, a comparison with the adjusted target resistance value RO is performed in step (A).

If the measured value is R8 or less, the adjustment of 'C for that heating resistor is completed. If C does not fall below RO, a C pulse is applied by increasing the peak value of the applied voltage pulse by Δt (step @).

In this way, the C adjustment is performed in principle until the measured value becomes R or less. However, there are some unique elements in which the resistance value decreases no matter how much pulse voltage is applied. Further, there is a limit to the peak value of the pulse voltage generated by the pulse generating circuit αQ. Therefore, if the resistance value does not become less than R0 (C also ends the adjustment when the number of pulse voltage applications reaches a certain number).

A step fence is provided for this purpose.

It has already been described in FIGS. 2 and 8 that the C resistance value is measured using several heating resistors as a group.

When the adjustment for one group is completed, the CPUs O and 4 perform calculations ΣR1 and ΣR2 to obtain the average value and the ridge deviation.

And the C printer slope is - the maximum value of the group, the average value.

The minimum value is printed like the third prisoner. - 7CPt for all heating resistances of Surf I head after °C adjustment
J041. ! Calculate the overall mean and standard deviation σ. The results are printed on the printer.

FIG. 7 is a detailed explanation of the head of the 45th pulse generation circuit. , chest odor 'C1 copper, @9 wheel is a flip-flop circuit, <(υ, (7), to) is a timer circuit, (2) is a pulse generator, (to) is a monostable multi-circuit, (to) is a Transistor, (b) is a voltage power supply, (to) is a counter, and (to) is a comparator.

When the start signal 5TART signal is received from the calculation unit U, the flip-flop circuit KOJI and @ are set. An ENABLE inhibit signal is sent from the flip-flop and circuit section to the calculation section. The ENABLE prohibition prohibits the change of the wave value signal Vs and the generation of the 5TART signal while the signal continues. The output of the flip-flop circuit causes a switch (
9) The coil is energized, and the contact point and direction are switched to the opposite side as shown in the diagram. The flip-flop circuit (to) is set and the timer circuit 01J outputs after T1 time from °C.

As a result, when the flip-flop circuit (to) is set, the gate (2) is opened, and the pulse generated by the /malus generation circuit (to) is given to the monostable multi-circuit (to). The monostable multicircuit shapes the pulse width of the pulse generator into a pulse having the desired pulse width Δt. Δt is determined by C by the resistor and capacitor in the monostable multicircuit. FIG. 8 shows the output pulse waveform of the pulse generator (to) and the output waveform of the monostable Manoshichi circuit (to).

The gate drive current of the transistor is supplied by the pulse of the monostable multi-circuit (2), and the transistor 'C is in the ON state for a period Δt when the pulse exists. While the transistor is in the ON state, the output voltage of the voltage source (2) is applied to the temperature sample through the contact line of the switch (9) and the relay network (8). The peak value of the voltage power source - is determined by the peak value signal Vs from the calculation section 20C.

The pulses passing through the gate (b) are counted in °C by a counter (7). The count value of the counter (7) is compared with a number n given from the C calculation section by a comparator.

When the count value reaches n, the flip-flop circuit (to) is reset by the output of the comparator (to). As a result, the gate is closed, and one application of Norculus voltage to the sample is completed.

The output of the comparator is also given to the timer circuit.

After the time limit T2, the timer circuit (2) outputs an output, thereby resetting the C flip 70 knob (2) and switching the switch (9) to resistance measurement. When the switch (9) is switched, the contacts are switched to the indicated positions, and the resistance value of the heating resistor of sample C is measured by resistance measurement.

The timer circuit outputs an output, and when T1 time has elapsed since C, the timer circuit outputs an output, which resets the flip-flop circuit and the Q terminal output becomes ``HH'' level and becomes ENAB.
The LE prohibition signal disappears. This allows the application of the next voltage pulse.

The experimental results of the change in resistance value according to the present invention (1θ) show that when the present invention is not implemented, the absolute value is ±20% in the Sarnle head having 2000 or more heating resistors each.
, the standard deviation 4 was 5.6%, but when the present invention was implemented, the variation in resistance was significantly improved, with an absolute value of ±8% and a standard deviation of 0.496. This made it possible to almost eliminate density unevenness in printing by the C thermal head.

The inventors set the initial setting value (Vo in FIG. 1) of the wave height of the voltage pulse applied to adjust the resistance value to several tens of volts, and set the increment of the applied pulse voltage every time Δt elV to several volts, 1
Number of pulses included in voltage application times n' x 1G~go
The resistance value of the °C heating element was adjusted by setting the pulse width Δt of 1 g to 1 to several seconds and the pulse interval to several tens of seconds.

Time limit Ts, T3 is Ion seconds after the song, time limit T! was set to several milliseconds, and the inventors adjusted the resistance value.

The specific values of the parameters used to adjust the resistance value are as follows.
It goes without saying that the present invention is not limited to the example described above, and that any number of numerical values can be adopted within the range that produces the effects of the present invention.

Step ① in Fig. 6 is compared in size with the previous resistance measurement value, but instead of this, it is possible to compare the resistance measurement value with the previous resistance measurement value within a certain range of °C, say 0.9 ~ Check whether it is within the range of 1.0 times or not, and if it is not within this range, remeasure the resistance value.

An example of the thermal head manufacturing apparatus according to the present invention is shown in the fourth example.
Although shown in Figure 7, the present invention is not limited thereto.

Although the peak value of the pulse voltage and the number of pulses n are automatically given to the pulse generating circuit αQ from the calculating section 4, it is also possible to set these manually. it is,
By providing the pulse generation circuit with a switch for setting the peak value Vs and the number of pulses n, this can be easily carried out. Also, C is also good, using both automatic setting from the calculation unit @ and manual operation.

In the example of Fig. 7, the switch (9) energizes the coil υυ.
It is a relay that drives the C contact-0 hard, but instead of this
It is also possible to use C semiconductor switches.

〔Effect of the invention〕

The thermal head manufacturing apparatus according to this invention is equipped with a pulse generation circuit that applies a voltage pulse to one heat-generating resistor to reduce the °C resistance value, and a resistance meter that measures the resistance value of the heat-generating resistor. Therefore, variations in the resistance value of the heating resistor of the thermal head can be reduced, and unevenness in print density of the thermal head can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the principle of the method for manufacturing a thermal head according to the present invention, and FIGS. 2 and 8 are diagrams showing cases in which the manufacturing process of the thermal head manufacturing apparatus according to the present invention is not carried out to equalize the resistance values, and when it is carried out. FIG. 4 is a configuration diagram showing an embodiment of the thermal head manufacturing apparatus according to the present invention, FIG. 5 is a waveform diagram of the main part of the fourth case, and the sixth factor is In the thermal head manufacturing apparatus according to the present invention, a flowchart showing an example of the J-Line manufacturing process, FIG. 7 is a detailed configuration diagram of the pulse generation circuit shown in FIG. 4, and FIG. Figure 9 is a diagram explaining the waveforms, Figure 9 is a general configuration diagram of a thermal head, Figure 10 is a diagram explaining how the thermal head is used in a thermal recording device, and Figure 11 is an example of the distribution of resistance values in a general thermal head. FIG. In the figure, r% (1) is the insulated substrate, (2) is the lead wire, (
3) is a heating resistance element, (6) is a blobbing device ffi,
(7) Hassan Rufud, (8) relay network, (9)
is a switch, ao is a pulse generation circuit, (b) is a resistance meter,
□□□ is the calculation section, Q4J is the CPU, C3υ, IQ, (b) is the timer circuit, unit is the pulse generator, (to) is the monostable
Furte circuit, (to) is the voltage power supply, (to) is the counter, and ■ is the comparator. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A thermal head manufacturing apparatus includes a pulse generation circuit that applies a voltage pulse to a heat generating resistor of a thermal head, and a resistance meter that measures a resistance value of the heat generating resistor.