JPH0338355A - Fuzzy controlling apparatus of printing density of printing head - Google Patents

Abstract

PURPOSE:To maintain the printing density constant at all times thereby to secure good printing quality by controlling the voltage impressed to a printing head to be the most proper value corresponding to the temperature of a heat-sensitive element, the impressing cycle and the issuing cycle of tickets. CONSTITUTION:A CPU 1 outputs a temperature detecting signal (t), an impressing cycle detecting signal (a) and a ticket issuing cycle detecting signal (b) in accordance with a program stored in a ROM 5 based on an input from a temperature detecting circuit 2, an impressing cycle detecting circuit 3 and a ticket issuing cycle detecting circuit 4, respectively. A signal selecting/latch circuit 8 selects and latches the temperature detecting signal (t), impressing cycle detecting signal (a) ticket issuing cycle detecting signal (b) from the CPU 1 and sequentially generates a single signal. A fuzzy logic engine 9 sets a fuzzy rule which has each signal (t),(a),(b) input through the CPU 1 and signal selecting/latch circuit 8 from the respective circuits 2,3,4 as a front part and the impressing voltage to a thermal printing head 6 as a rear pat. The most proper operating amount Z1 is output by the engine 9 based on the fuzzy rule from the detecting factors detected by the detecting circuits 2,3,4 and, an impressing voltage controlling circuit 11 is fuzzy-controlled through a control part 10 by the operating amount Z1.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a print density fuzzy control device for a print head used in, for example, a ticket issuing processing device, which automatically variably controls the print density of a print head. Regarding.

(B) Prior Art Conventionally, ticket issuing processing apparatuses equipped with thermal transfer type print heads such as thermal print heads can be broadly classified into the following two types.

In other words, there is a device that performs printing and issuing processing by constantly applying a constant voltage regardless of the temperature of the heat-sensitive element and its surroundings, and a device that detects the temperature of the heat-sensitive element and uses a feedback circuit to variably control the voltage applied to the print head. There are two types of devices:

(c) Problems to be Solved by the Invention The print density by the above-mentioned thermal print head is not limited to the temperature of the heat-sensitive element, but also because the period of application to each dot pin differs depending on the characters and designs on the printed ticket surface. The shading changes depending on the printed character density (in other words, the cursor application cycle) or the ticket issuing cycle, whether continuous ticketing or intermittent ticketing.

However, in the above-mentioned conventional device, applied voltage control is not performed that takes into account the temperature of the heat-sensitive element, the application cycle, and the ticket issuing cycle, which inevitably causes shading in the print density, making it difficult to print well. The problem was that it was difficult to ensure quality.

This invention maintains a constant print density and ensures good print quality by controlling the voltage applied to the print head to the most appropriate value in accordance with the temperature of the thermal element, the application cycle, and the ticket issuing cycle. An object of the present invention is to provide a print density fuzzy control device for a print head that can achieve the following.

(d) Means for solving the problems This invention provides a thermal print head equipped with a heat-sensitive element,
Applied voltage control means for controlling the voltage applied to the print head, first detection means for detecting the temperature of the heat sensitive element, second detection means for detecting the application cycle, and third detection means for detecting the ticket issuing cycle. , a fuzzy rule is set in which the detection elements from each of the detection means are the antecedent part and the applied voltage of the print head is the consequent part, and the detection elements detected by each of the detection means are set as the consequent part. Fuzzy inference control means outputs the most appropriate operation amount based on a fuzzy rule, and performs fuzzy inference control on the applied voltage control means using the operation amount. do.

(E) Effect According to the present invention, the above-mentioned No. 1 detecting means detects the temperature of the heat-sensitive element, the second detecting means detects the application cycle, and the third t*chisen means ticket issuing cycle, and the fuzzy inference control means detects the temperature of the heat-sensitive element. The most appropriate operation amount (applied voltage) is output based on fuzzy rules using the detection elements from each of the above-mentioned detection means as the antecedent part, and the above-mentioned applied voltage control means is controlled by fuzzy inference using this operation amount.

(F) Effect of the invention As a result, the voltage applied to the thermal print head, that is, the print density by the thermal print head, is controlled to the most appropriate value corresponding to the temperature of the heat-sensitive element, the application cycle, and the ticket issuing cycle. This has the effect of keeping the print density constant at all times and ensuring good print quality.

(g) Examples of the invention An embodiment of the present invention will be described in detail below based on the drawings.

The drawing shows the print density fuzzy control device of the print head,
In FIG. 1, the CPU generates a temperature detection signal t1, an application cycle detection signal a1, a ticket issue cycle detection signal, according to a program stored in a ROM 5 based on inputs from a temperature detection circuit 2, an application cycle detection circuit 3, and a ticket issue cycle detection circuit 4. At the same time, the RAM 7 outputs the data and controls the driving of the thermal print head 6, and the RAM 7 stores necessary data.

Here, the temperature detection circuit 2 described above is connected to the thermal print head 6.
The above-mentioned application cycle detection circuit 3 is a second detection means for detecting the application cycle to the dot pin, and the above-mentioned ticket issuing cycle detection circuit 4 is a first detection means for detecting the temperature of the heat-sensitive element. This is a third detection means for detecting the ticket issuing cycle.

Signal selection latch circuit 8 connected to the next stage of the above-mentioned CPUI
selectively latches each signal from the CPUI, that is, the temperature detection signal t1, the application cycle detection signal a1, and the ticket issue cycle detection signal S, and sequentially outputs a single signal.

The fuzzy inference engine (same as the fuzzy controller, hereinafter simply abbreviated as FIE) 9 includes each of the above-mentioned circuits 2.3.
．． 4 through the CPUI and the signal selection latch circuit 8.

A fuzzy rule is set in which b is the antecedent and the voltage applied to the thermal print head 6 is the consequent. The most appropriate operation amount Zl is output based on the fuzzy rule, and the applied voltage control circuit 11 is controlled by fuzzy inference via the control unit 10 using this operation amount Zl.

The above-mentioned fuzzy rules are set as shown in the fuzzy rule table 12 of FIG.

For example, if XI = PL, X2 = PL,
X3 = PL then Yl = NL i f XI = NLS X2 = NL,
Each antecedent part XI, X2 . A production rule is set in which the label of the fuzzy variable of X3 and the label of the fuzzy variable of the consequent part Yl are approximately inversely proportional.

Note that in FIG. 1, only a part of the production rule is shown for convenience of illustration.

FIG. 2 shows the membership function of the ambient temperature (corresponding to the signal t and the antecedent part XI) output from the above-mentioned temperature detection circuit 2 via the CPUI, and in this antecedent part membership function, each label is Nl Very low NM: Low NS: Slightly low zR: Standard PS: Slightly high PM: High PM: Very high.

FIG. 3 shows the membership function of the application period (corresponding to signal a and antecedent part , NL: Extremely sparse NM: Sparse NS: Slightly sparse ZR: Standard PS: Slightly dense PM: Dense PL: Extremely dense.

FIG. 4 shows the membership function of the ticket issuing cycle (corresponding to the signal and antecedent part x3) outputted from the ticket issuing cycle detection circuit 4 through the CPU 1, and in this antecedent part membership function, each label is , NL: Extremely sparse NM/Sparse NS, Slightly sparse ZR: Standard PS: Slightly dense PM: Dense PL: Extremely dense.

FIG. 5 shows the membership function of the applied voltage Yl of the thermal print head 6 (the value as the consequent, unlike the manipulated variable Zl in FIG. 1), and in this consequent membership function, each label is NL: Extremely low NM: Low NS: Slightly low ZR: Standard PS: Slightly high PM: High PL: Extremely high.

The fuzzy inference control operation of the print density fuzzy control device for the print head configured as described above will be explained.

The above-mentioned temperature detection circuit 2 detects the temperature XI of the heat-sensitive element (see Fig. 2), and the application period detection circuit 3 detects the application period X2.
(see Figure 3), and when the ticket issuing cycle detection circuit 4 detects the ticket issuing cycle X3 (see Figure 4), the print head 6
When the applied voltage corresponding to the print density is controlled by fuzzy inference using FIE9, the following results are obtained.

First, as shown in FIG.
2. M in the above FIEQ from each label (fuzzy value of fuzzy variable) of the antecedent part including the ticketing cycle X3 and the grade
The IN circuit calculates the goodness of fit of the antecedent part.

Rule ■XI = PS (0,6) X2 = PM (0,84) X3 = PS (0,88) Compatibility 0.6 Rule ■XI = PS C0,6) X2 = PS (0,16) X3 = PS (0,88) Degree of suitability 0.16 Rule ■XI = PS (0,6) X2 = PM (0,84) X3 = ZR (0,12) Degree of suitability 0.12 Rule ■x+ = ps (0, 6) X2 = PS (0,16) X3 = ZR (0,12) Compatibility 0.12 Rule ■XI = PM (0,4) X2 = PM (0,84) X3 = PS (0,88) Compatibility degree 0.4 Rule ■XI = PM (0,4) X2 = PS (0,16) X3 = PS (0,88) Degree of suitability 0.16 Rule ■XI = PM (0,4) ,84) X3 = ZR (0,12) Fit 0.12 Rule ■XI = PM (0, 4) X2 = PS (0, 16) X3 = ZR (0, 12) Fit 0.12 Before the above The suitability of the subject part is the smallest value of the grade of each human power in the rule, so-called m1n (minimum).

Next, the above-mentioned FIE 9 modifies the membership function of the consequent part in accordance with each of the above-mentioned fitness degrees.

In other words, if the height of each fuzzy set shown in Figure 6 is corrected to match the fitness of the antecedent part, the shape of the fuzzy set of the consequent part Yl of the above production rule will be as shown in the shaded area in Figure 6. Become.

In other words, rule ■Yl = NS (0, 6) (see the shaded area) rule ■Yl = NS (0, 16) (see the shaded area)
Rule ■Yl = NS (0, 12) (See the shaded area) Rule ■Yl = NS (0, 12) (See the shaded area) Rule ■Yl = NM (0, 4) (See the shaded area) Rule ■Yl = NS (0,16) (See the shaded area) Rule ■Yl = NS (0, 12) (See the shaded area) Rule ■Yl = NS (0, 12) (See the shaded area) Next, F
The MAX circuit in the IEQ makes an integrated judgment on the results of the above-mentioned rules and determines the manipulated variable Zl.

That is, by adding up the fuzzy sets resulting from the above eight fuzzy rules
(Max) and determine the manipulated variable Zl.

At this time, the area where the maximum area of the voltage Yl applied to the thermal print head 6 (the shaded area in FIG. 7) is divided into two, that is, the center of gravity, is determined as the operation amount Zl, and this is the most appropriate operation amount. .

In other words, the voltage applied to the thermal print head 6 described above is
In this example, the applied voltage Zl is a low value (
NM) and a slightly lower value NS, and the applied voltage control circuit 11 is driven and controlled so that this operation fiZ+ (strictly speaking, the final output after defuzzifying this value Zl) is obtained. It turns out.

By executing such fuzzy inference control of the voltage applied to the thermal print head 6, a print density corresponding to the applied voltage can be obtained, and this print density corresponds to the temperature of the thermal element, the application cycle, and the ticket issuing cycle described above. Since the printing density is controlled to the most appropriate value, it is possible to always keep the printing density constant and ensure good printing quality.

In the correspondence between the structure of the present invention and the above-described embodiments, the application control means of the present invention corresponds to the applied voltage control circuit 11 of the embodiment, and similarly, the first detection means corresponds to the temperature detection circuit 2. Correspondingly, the second detection means corresponds to the application period detection circuit 3, and the third detection means is
Although the fuzzy inference control means corresponds to the ticket issuing cycle detection circuit 4 and the FIE 9, the present invention is not limited to the configuration of the above-described embodiment.

For example, in the above-described embodiment, 7 labels are set for both the antecedent part and the consequent part, but other labels such as 5 labels and 10 labels may be set.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a block diagram showing a print density fuzzy control device for a print head, FIG. 2 is an explanatory diagram showing an antecedent membership function of ambient temperature, and FIG. An explanatory diagram showing the membership function of the antecedent part of the application period; FIG. 4 is an explanatory diagram showing the membership function of the antecedent part of the ticket issuing cycle; FIG. FIG. 6 is an explanatory diagram of fuzzy inference control, and FIG. 7 is an explanatory diagram of determining the manipulated variable. 2... Temperature detection circuit 3... Application cycle detection circuit 4... Ticketing cycle detection circuit 6... Thermal print head 9... F 1... Applied voltage control circuit Figure 2, Figure 3, Figure 4 Kei J or man's 1vH A member'nn 7th floor special nail 71 de Ming figure original 17 cow 8p fuji (gu [body L (Y+)
Figure 7: Explanatory diagram of withdrawal demon determination

Claims (1)

[Claims] (1) A thermal print head equipped with a heat-sensitive element, an applied voltage control means for controlling the voltage applied to the print head, a first detection means for detecting the temperature of the heat-sensitive element, and a second detection means for detecting the application period. a third detection means for detecting the ticket issuing cycle; a fuzzy rule is set in which the detection elements from each of the above detection means are used as an antecedent part, and correspondingly the voltage applied to the print head is set as a consequent part. and fuzzy inference control means for outputting the most appropriate operation amount based on the fuzzy rule from the detection elements detected by each of the detection means, and controlling the applied voltage control means using the operation amount using fuzzy inference. Head print density fuzzy control device.