JPH04124643U - Heat storage correction circuit for thermal transfer printers - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the print quality of thermal transfer printers by performing highly accurate heat accumulation correction based on print data. [Structure] Prediction calculation circuits 11, 12, and 13 predict each heat storage energy of the base 3 of the thermal head 1, the ceramic base 2, and the aluminum heat sink 5, and based on the prediction results of each of these prediction calculation circuits 11, 12, and 13. Correction calculation circuits 14, 15, and 16 are provided to perform correction calculations.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to thermal transfer printers, in particular to correcting changes in recording density due to heat storage effects. The present invention relates to a heat storage correction circuit.

0002

[Conventional technology]

In thermal transfer printers, the heating resistor of the thermal head is The ink on the ink ribbon is transferred to the receiving paper by applying electricity to the heating resistor. As the energization interval becomes shorter, the effect of heat accumulation in the heating resistor due to past energization increases. The print quality deteriorates. Therefore, conventionally, for example, Japanese Patent Application Laid-Open No. 59-98878 As stated in the report, the heat storage energy of the heating resistor is calculated based on the printed data. The current flow to the heating resistor is corrected based on the predicted result. There is.

0003

[Problem that the idea aims to solve]

However, thermal heads generally generate heat through the base on a ceramic base. The structure is such that a resistor is formed and a ceramic base is fixed with an aluminum base. Therefore, heat storage occurs in each of these parts, and the physical thermal time constant is the same. Therefore, it is not possible to simply predict and correct the heat accumulation in the heating resistor as in the past. Optimal correction cannot be performed and sufficient print quality cannot be obtained.

0004

[Means to solve the problem]

In order to solve the above problems, this invention aims to reduce the amount of thermal energy stored in each component of the thermal head. Based on the prediction results of these multiple prediction methods, A plurality of correction means are provided for correcting the amount of current applied to the heating resistor.

[0005]

[Effect]

Predict the heat accumulation in each part that makes up the thermal head and make corrections based on each prediction result. Therefore, optimal correction can be performed.

[0006]

【Example】

Embodiments of the present invention will be described below with reference to the accompanying drawings. Figure 1 shows the results obtained by applying the present invention. A configuration diagram of the thermal head of a thermal transfer printer, Figure 2 shows the heat accumulation correction circuit of the same printer. Figure 3 is a waveform diagram showing an example of the output waveform of the circuit, Figure 4 is the final diagram of the circuit. It is an enlarged view of an output waveform.

The thermal head 1 of this thermal transfer printer has a structure in which a heating resistor 4 is formed on a ceramic base 2 via a base 3, and the back surface of the ceramic base 2 is fixed with an aluminum heat sink 5. The physical time constants of each part are generally τ 1 , where the thermal time constant of the base 3 is τ ₁ , _the thermal time constant of the ceramic base 2 is τ ₂ , and the thermal time constant of the aluminum heat sink 5 is τ ₃ The relationship is <τ ₂ <τ ₃ .

Therefore, as shown in FIG. 2, the heat storage correction circuit includes three predictive calculation circuits 11, 12, and 13 connected in parallel, three correction calculation circuits 14, 15, and 16, and a ROM17. and an adder 18. The prediction calculation circuit 11 sets the time constant t ₁ to the time constant τ ₁ of the base 3, predicts the heat storage energy of the base 3 based on the print data D, and outputs the prediction result B1 and the print data D.

Further, the prediction calculation circuit 12 sets the time constant t ₂ to the time constant τ ₂ of the ceramic base 2, predicts the heat storage energy of the ceramic base 2 based on the print data D, and outputs this prediction result B2. Further, the prediction calculation circuit 13 sets the time constant t ₃ to the time constant τ ₃ of the aluminum heat sink 5, predicts the heat storage energy of the aluminum heat sink 5 based on the print data D, and outputs this prediction result B3.

0010 On the other hand, the correction calculation circuit 14 receives the print data D from the prediction calculation circuit 11 and the prediction result. B1 and the output G1 from the ROM 17 corresponding to the print data D are input, and the storage in the base 3 is A correction output S1 according to thermal energy is output.

[0011] Further, the correction calculation circuit 15 receives the print data D from the prediction calculation circuit 11 and the prediction calculation circuit. The output G2 from the ROM 17 according to the prediction result B2 from the path 12 and the print data D is input and output a correction output S2 according to the heat storage energy of the ceramic base 2. . Furthermore, the correction calculation circuit 16 receives the print data D from the prediction calculation circuit 11 and the prediction calculation circuit. The output G3 from the ROM 17 according to the prediction result B3 from the path 13 and the print data D is input and output a correction output S3 according to the heat storage energy of the aluminum heat sink 5. Ru.

0012 Then, in the adder 18, the print data D from the prediction calculation circuit 11, the correction calculation circuit Each correction output S1, S2, S3 from paths 14, 15, 16 is input and added, and this Output the addition result as the final output.

[0013] The operation of the heat storage correction circuit configured as above will be explained with reference to FIG. For example, when print data D as shown in FIG. The prediction result B1 as shown in FIG. The prediction result B2 shown in FIG. ) are output, respectively, and the correction calculation circuits 14, 15, 1 6 is input.

[0014] Then, the correction calculation circuit 14 outputs the result obtained by subtracting the prediction result B1 from the print data D. The result is multiplied by the output G1 from the ROM 17 to produce a corrected output S1 as shown in FIG. S1=(D-B1)×G1} is output.

[0015] In addition, the correction calculation circuit 15 outputs the result of subtracting the predicted result B2 from the print data D. The corrected output S2 as shown in the same figure (f) multiplied by the output G2 from the ROM 17 =(D-B2)×G2} is output. Furthermore, the print data is output from the correction calculation circuit 16. The same figure ( A corrected output S3 {S3=(D-B3)×G3} as shown in g) is output.

[0016] Then, print data D and correction outputs S1, S of each correction calculation circuit 14, 15, 16 2, S3 is added by the adder 18 to produce the corrected print data as shown in FIG. 4, for example. The final output, which is the data, is output. The part of this final output excluding print data D is Although it is the sum of the correction outputs S1, S2, and S3, each prediction calculation circuit 11, 12 , 13 have different time constants, parts A and D mainly use the correction output S1+S2. +S3 is the correction output for the B section and E section, and the correction output S2+S3 is the main correction output for the C section and F section. Output S3 will be involved.

[0017] In this way, predictions are made according to the time constants of each part that makes up the thermal head 1. Since it performs correction, it is possible to perform highly accurate correction that cannot be obtained with a single time constant. You will be able to do it.

[0018]

[Effect of the idea]

As explained above, according to the present invention, heat accumulation in each part of the thermal head can be reduced. Since it makes predictions and makes corrections based on the results of each prediction, it is possible to make optimal corrections. , print quality is improved.

[Brief explanation of drawings]

[Figure 1] Configuration diagram of a thermal head of a thermal transfer printer to which the present invention is applied

[Figure 2] Block diagram of the printer's heat accumulation correction circuit

[Figure 3] Waveform diagram showing an example of the output waveform of the same circuit

[Figure 4] Enlarged diagram of the final output waveform of the same circuit

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Thermal head, 2...Ceramic base, 3...Base, 4...Heating resistor, 5...Aluminum heat sink, 11,
12, 13... Prediction calculation circuit, 14, 15, 16... Correction calculation circuit, 17... ROM, 18... Adder, D... Print data, B1, B2, B3... Prediction result, G1, G2, G3...
ROM output, S1, S2, S3...correction output.

Claims (1)

[Scope of utility model registration request] 1. A heat storage correction circuit for a thermal transfer printer that predicts the heat storage energy of a heat generating resistor of a thermal head based on print data and corrects the amount of current applied to the heat generating resistor of the thermal head based on the prediction result. , this heat storage correction circuit includes a plurality of prediction means for predicting the heat storage energy of each component of the thermal head, and a plurality of prediction means for correcting the amount of current applied to the heating resistor based on the prediction results of the plurality of prediction means. 1. A heat storage correction circuit for a thermal transfer printer, comprising a correction means.