JPS60192665A - Control of thermal recording head - Google Patents

Abstract

PURPOSE:To control a thermal recording head to secure almost the uniform heating value by generating a pulse having a recording pulse width corresponding to representative resistance values of a plurality of heat generating body substrates to drive resistors on the heat generating body substrates. CONSTITUTION:In a thermal recording head made up of a plurality of substrates 2A and 2B joined, a means is provided to generae a pulse having a recording pulse width corresponding to representative resistance values of the substrates 2A and 2B. Resistors on the substrates 2A and 2B are driven by a pulse generated by the pulse generation means. Thus, individual heat generating elements can be driven with the recording pulse width correspondning to average resistance values of the substrates 2A and 2B thereby the controlling of the thermal recording head with a simple mechanism to secure almost uniform heating value.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method of controlling a thermal recording head, and more particularly to a method of controlling a thermal recording head comprising a plurality of heating element substrates joined together.

Prior Art When constructing a thermal recording head with a wide recording width, using a method of joining multiple heating element substrates is not only advantageous in terms of yield, but also reduces the variation in resistance value within a single substrate. It's small enough.

It is well known that there is an advantage that uniformity of output density can be easily obtained.

Conventionally, when configuring a thermal recording head by piecing together a plurality of heating element substrates as described above, those having relatively similar average resistance values were selected from among the large number of heating element substrates and combined. .

However, as described above, the method of selecting heating element substrates with similar average resistance values and combining them has a serious problem of significantly reducing productivity.

In addition, even if sufficient care is taken in selection and combination, there is a problem in that a certain degree of density difference occurs at the joints of the heating element substrates, resulting in a reduction in image quality.

To prevent this, it is conceivable to provide adjustment means such as a volume on each heating element board so that a constant power is supplied to each heating element board, but the structure becomes complicated. In addition, another problem arises in that it is necessary to adjust the volume and the like.

Purpose The present invention has been made in view of the above circumstances, and its purpose is to solve the above-mentioned problems in conventional thermal recording heads and to use a thermal recording head composed of a plurality of heating element substrates. By improving the driving method when
An object of the present invention is to provide a method for controlling a heat-sensitive recording head that can control the amount of heat generated so that the amount of heat generated is as follows.

Configuration The present invention will be described in detail below, and then the configuration of the present invention will be explained in detail based on embodiments.

FIG. 1 is an enlarged sectional view showing an example of a thermal recording head having a plurality of heat generating substrates (hereinafter simply referred to as "substrates"), which is the object of the present invention. In the figure, l is a support plate, 2
A indicates the first substrate, and 2B indicates the second substrate.

Now, let us assume that the average resistance values of the substrates 2A and 2B are respectively A and T, the power supply voltage is 1, and the applied powers of the substrates 2A and 2B are PA and PB, respectively.However, R, , R, is the wiring resistance, and ■β and Vδ are the on-voltage of the driver.

becomes. here, RA - RB = ΔR Vβ − Vδ = Δ■ 1-1 give = to r Then, ΔR>ΔV, Δr to 8R, so ■β.

Ignoring Vδ, RCl, and Rr, the energy Q applied to the substrate is determined by the voltage application time JtTAtT
In this case, Q=PA xTA=PB xTB. Therefore.

Therefore, if it is generalized as follows, the concentration due to the substrates 2A and 2B becomes a constant value. This is the principle of the invention.

FIG. 2 is a diagram showing a control mechanism of a thermal recording head according to an embodiment of the present invention. In the figure, 10a to LOn indicate heating elements, 3A is a timer that energizes the heating element on the substrate 2A, 3B is a timer that energizes the heating element on the substrate 2B, 4 is a counter, 5 is a decoder, 6 indicates a latch group, and 7 indicates a shift 1 register group. fever cord 10
a-10it is divided into 8 groups.

The timers 3A and 3B each have a board 2A.

The voltage application times TA and TB calculated by the above equation (1) are set according to the average resistance value of 2B. Further, the counter 4 is roooJ, rlooJ, roloJ, r
llOJ.

This counter cycles in the order of ``rool'', ``rlol'', ``roll'', and ``rllll'', and is initially set to roooJ.

The operation of this embodiment configured as described above will be explained below.

When the recording signal pulse is input, the counter 4 becomes rooo.
Since the timer 3A is set to J, the timer 3A is selected via the AND gate 8A. As a result, the output of the NOR gate 9 changes from "11" to rLJ, the output enable signal ll becomes [■(], the contents of the counter 4 are output from the decoder 5, and the heating elements of the first group are driven. be done.

When the set time of the timer 3A has elapsed, the output enable signal 11 becomes "I("), and as a result, the counter 4
is incremented by "1" and becomes rlooJ.

Here, in the same way as above, the output enable signal 117)t
r HJ, the contents of the counter 4 are output from the decoder 5, and the second group of heating elements is driven.

Thereafter, the counter contents up to rllOJ are outputted by the same operation, and after driving up to the fourth group of heat generating elements, the counter 4 is incremented to "rool", and the timer 3B is selected via the AND gate 8B. Ru. This results in
Thereafter, the fifth to eighth groups of heating elements are driven in the same manner as above.

According to this embodiment, each heating element can be driven with a recording pulse width corresponding to the average resistance value of each of the substrates 2A and 2B. It becomes possible to control the amount.

Also, by transforming the above equation (1).

If so, the concentrations at the connection portion of the substrates 2A and 2B can be made closer to each other. In formula (2), R
Q and RQ respectively indicate the resistance values of heating elements on the substrates 2A and 2B adjacent to each other at the connection portion of the substrates 2A and 2B.

The embodiment shown in FIG. 2 is just a configuration example,
It goes without saying that the present invention should not be limited to this.

For example, the number of substrates to be connected, the number of divided groups of heating elements, the configuration of counters and decoders, etc. can be freely selected.

Effects As described above, according to one aspect of the present invention, in a method for controlling a thermal recording head made up of a plurality of substrates joined together, a pulse having a recording pulse width corresponding to the representative resistance value of each of the plurality of substrates is generated. Since the pulse generated by the pulse generating means drives each resistor on the plurality of substrates, the configuration is simple and can be easily performed later.
This has the remarkable effect that it is possible to realize a method of controlling a thermal recording head that can be controlled so that the amount of heat generated is as follows.

Furthermore, by setting the above representative resistance value to the resistance value of the heating elements adjacent to each other at the connection portions of the plurality of substrates, the change in resistance value between the substrates can be made almost continuous, and the resistance value can be made substantially continuous between the substrates. It also has the effect of eliminating concentration differences that tend to occur.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing an example of a thermal recording head having a plurality of substrates, which is the object of the present invention, and FIG. 2 is a diagram showing the control and structure of the thermal recording head, which is an embodiment of the present invention. be. l: support plate, 2A, 2B: board, 3A, 3B: timer,
4: Counter, 5: Decoder, 6: Latch group, 7: Shift 1 register group, 1Oa-10n: Heat generating element.

Claims (3)

[Claims] (1) A method for controlling a thermal recording head formed by splicing a plurality of heat generating substrates, comprising means for generating a pulse having a recording pulse width corresponding to a representative resistance value of each of the plurality of heat generating substrates; A method for controlling a thermal recording head, characterized in that each resistor on the plurality of heating element substrates is driven by a pulse generated by a pulse generating means. (2) Control of a thermal recording head according to claim 1, wherein the representative resistance value of the plurality of heat generating substrates is an average value of the resistance values of the resistors on each heat generating substrate. Method. (3) The heat sensitive according to claim 1, wherein the representative resistance value of the plurality of heating element substrates is the resistance value of the resistor elements adjacent to each other at the connection part of the plurality of heating element substrates. How to control the recording head.