JPS62236767A - Density difference correction circuit of thermal transfer serial printer - Google Patents

Abstract

PURPOSE:To make the printed shape of a first row and that of a second row identical by a method wherein the printing pulse width of the second row is made smaller than the printing pulse width of the first row on the basis of the quantity of printing information. CONSTITUTION:First raw printing information is sent not only to a printing pulse generating circuit 1 for printing to be supplied to the first raw printing head 2 to carry out printing but also to a first row printing information memory circuit 3 so as to be held thereto. Second row printing information is sent to a printing pulse control circuit 5 to generate a basic pulse Tf. The second row printing information is also sent to a printing information discriminating circuit 4 to be compared with the first row printing information of the memory circuit 3 and the comparing result is sent to the printing pulse control circuit 5 to respectively generate control pulses T1, Tr, Tt. The printing pulse of the first row printing head 2 is Tf+Tt, and T1 of a (m+2)-th line and tr of a (m+3)-th line are respectively values determined by the remaining of heat of the first row.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a density difference correction circuit for reducing density differences between two format print heads of a thermal transfer serial printer.

[Conventional technology]

Conventionally, in a thermal transfer serial printer having a two-format print head t, printing was performed by applying the same print pulse mt to the first and second columns.

[Problem that the invention seeks to solve]

The conventional thermal transfer serial printer with a two-format print head described above applies the same printing pulse to the first and second columns, so the heat generated during printing of one column is transferred to the ink ribbon, It remains on the paper and platen and becomes a secondary heat source when printing the second row, causing the print size of the second row to be larger than the intended one or the shape of the characters? There were drawbacks, such as characters that were deformed or had a large number of strokes, where vertical lines could connect with each other and become unreadable.

An object of the invention X' is to provide a circuit for correcting the density difference in a thermal transfer serial printer, which eliminates such drawbacks and is capable of correcting the density difference between two print heads.

[Means for solving problems]

The configuration of the density difference correction circuit of the present invention includes a memory circuit that holds the print information of the first column printed earlier in the two-format print head, and a memory circuit that holds the print information of the first column printed earlier in the two-format print head, and A print judgment circuit reads the print information of the first column before and after the print digit of the column from the memory circuit and compares it with the print information of the second column, and the print pulse width of the second column is determined based on the comparison result of the print judgment circuit. The present invention is characterized by comprising a print pulse control circuit that controls the print density difference between each column.

[5j! Example] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

The print information of the first column is sent to a printing pulse generation circuit 1 for printing, supplied to the print head 2 of the first column to execute printing, and sent to be held in a storage circuit 3. The second column of print information is also sent to the print pulse control circuit 5, which generates the basic pulse T/ shown in FIG.

Also, the print information in the second column is sent to the print information discrimination circuit 4 and compared with the print information in the first column in the storage circuit 3? The comparison result is sent to the print pulse control circuit 4, and the third
The control pulses t4 tr and 'rt shown in the figure are generated, respectively.

FIG. 2 is a print diagram showing an example of the second column of print information according to this embodiment. If the n-th and n+2-th digits have already been printed by the head 2 in the first column, and you want to print the n+1 digit on the print head 6 in the second column, the print data in the second line is Both the 1st digit and n+2 digit are 1. 2. 3
For those whose rows do not have print information, the same time width T/+Tt li as the print pulse of the print head 2 in the first column is applied. On the other hand, for the m+ row, both the 1st digit and the n+2 digit are m.

Since the printing information of the first column is in the m+l and m+2 rows, only a short time @Tf printing pulse is required to reduce the amount of heat generated in the second column by the residual amount of the heat already printed. Therefore,
At im+1n+1 digit, print pulse control circuit W&5 i is applied to print information determination circuit 4 to n+1 digit
c t 1. Pulses such as t r and T t are no longer generated. Also, n + 2nd digit t4m + 3rd row t
It is clear that r can be given as a pulse width a value determined by the residual heat in the first column.

〔Effect of the invention〕

As described above, the present invention provides the second row of printing pulses f
＠ヲ Depending on the amount or small amount of printing information, by reducing the printing pulse width from the first column, the effect is that the printed shapes in the first column and the printed shapes in the second column can be kept equal. be.

[Brief explanation of drawings]

8-1 is a block diagram of an embodiment of the present invention, FIG. 2 is a print diagram of an example of print information according to this embodiment, and FIG. 3 is a timing diagram of FIG. 1. 1...Print pulse generation circuit, 2.6...
・Print head (1st row, 2nd row), 3...
1st column storage circuit, 4... Print discrimination circuit, 5...
...Print pulse control circuit. −′＼ 、′ Agent Patent attorney Susumu Uchihara

Claims (1)

[Claims] A memory circuit that holds the printing information of the first column printed earlier in the two-column print head, and a memory circuit that stores the printing information of the first column printed earlier in the head, and a memory circuit that stores the printing information of the first column before and after the printing digits of the second column when printing the second column of the head. a print judgment circuit that reads information from the storage circuit and compares it with the print information of the second column; and a print pulse width of the second column is controlled based on the comparison result of the print judgment circuit to correct the print density difference of each column. A density difference correction circuit for a thermal transfer serial printer, comprising a printing pulse control circuit.