JPH029643A - Thermal recording control - Google Patents

Abstract

PURPOSE:To reduce the current capacity of a recording power supply, in thermal recording wherein a thermal printing heat generating resistor row is divided into a plurality of groups and printing is performed at every one group by mounting a means for making the number of divisions of the thermal printing heat generating resistor row, when the resistance value of said row is high, less than those when said resistance value is low. CONSTITUTION:When the center resistance value of a head is 1533OMEGA, 9-division printing is set in 192-dot simultaneous printing and, when the center resistance value thereof is 1255OMEGA, 11-division printing is set in 158-dot simultaneous printing. In 11-division printing, N : 11 is set and an image signal is transmitted eleven times. In the first transmission, a signal other than the first - 157-th dot image signals is set to a white signal and 1728 bits are transmitted to be latched by a latch circuit 3 and all of output control signals ENB 1-9 are brought to 'L' to perform the printing of the first - 157th dots. In the same way, the printing of one line is performed by transmitting image signals of eleven times. By this method, the peak current of recording due to the irregularity of a resistance value can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording system for facsimiles, printers, etc., and more particularly to a thermal recording system in which printing is performed using an array of heating resistors for thermal printing.

Conventional technology Conventionally, this type of thermal recording method has adopted a thermal recording method in which a heating resistor array for thermal printing is divided into groups each having the same number of dots, and printing is performed sequentially every 1 fF. At the time, printing was performed by energizing each resistor. Second
The figure shows the configuration of a thermal head, and FIG. 3 shows a conventional thermal recording control system.

The thermal head in Figure 2 has 1728 heating resistors 1-1~
1-17211 are arranged in a row on the head substrate.

One end of each of these heating resistors 1 is commonly connected to one end of an external M power source 25, and each other end is connected to the other end of the external power source 25 through the same number of drive circuits 2 as the heating resistors 1. There is. The drive circuit 2 is mainly composed of switching elements, and when performing 9-division printing, print signal information is supplied in parallel via a latch circuit 3, which will be described later, and outputs are supplied from output control signal input terminals 5 to 13. Control signal ENB
1 to 9, each switching element is turned on and each heating resistor 1 is individually energized.

A series of recording signal information such as a black and white binary facsimile image signal of 1728 bits per line is input to the recording signal input terminal 16 in series.

・Next, the conventional thermal recording method will be explained using FIG.

The image signal DATA is input to the shift register 4 in synchronization with the rise of the clock signal CLOCK. When the image signal of 1728 dots for one line is completely transferred to the shift register 4, the latch signal LATCH is latched by the latch circuit 3. Image signals supplied in parallel from the latch circuit 3 (
H” printing) and output control signal ENB 1 to EN[19 (”
The driving circuit is operated by the output of the output signal (L" enable) and printing is performed.

Problems to be Solved by the Invention -ffi is that the resistance value of thermal heads varies by about ±10% between heads. The resistance value at the center of the head is now 125.
Considering that the head current varies from 5Ω to 1533Ω, in the case of the conventional example shown in Fig. 3, a peak current of 2.9 A flows in the 1533Ω head and 3.5A flows in the 1255Ω head in order to print a maximum of 192 dots at the same time. Voltage 24V.

Driver voltage drop1. OV) Therefore, there is a drawback that the current capacity of the recording power source is required to be 3.5A.

The present invention has been made in view of the above-mentioned conventional situation,
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a new heat-sensitive recording control method that eliminates the above-mentioned drawbacks inherent in the conventional technology and makes it possible to reduce the current capacity of a recording power source.

Means for Solving the Problems In order to achieve the above object, the thermal recording control method according to the present invention divides a heating resistor array for thermal printing into a plurality of groups, and prints sequentially for each group. , when the resistance value of the heating resistor array for thermal printing is large, the resistance value is smaller than when it is small.
The device is configured to include means for reducing the number of FJs.

The present invention further includes means for performing divided printing by controlling the image signal applied to the drive circuit of the heating resistor for thermal printing.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a time chart for explaining one embodiment of the present invention.

In printing with the thermal head shown in FIG. 2, when the head center resistance value is 1533Ω, 192 dots are simultaneously printed to make 9 divisions, and when it is 1255Ω, +57 or 158 dots are simultaneously printed to make 11 divisions. In this way,
Both peak currents can be 2.9A. To do this, send the divided print to the output control signal ENB l.
9, but by controlling the image signal DATA. That is, to divide into 11, set N:11 in the time chart of FIG. 1, and transfer the image signal 11 times. In the first transfer, 1728 bits of the image signals other than the 1st to 157th dots are transferred as white signals, latched in the latch circuit 3, and output control signals ENII 1 to 9 are all set to Prints 157 dots,
While printing the 1st to 157th dots, the 158th to 314th dots
Transfers signals other than the dot image signal as a white signal, latches it to the latch circuit 3 and outputs it, 111v4 signal εNil 1 to 9
5: Set all dots to "L" and print the 158th to 314th dots. Similarly, one line is printed by transferring the image signal 11 times.

As described in detail, according to the present invention, when the resistance value of the heating resistor array for thermal printing is large, the number of divisions is made smaller than when it is small, thereby reducing the peak current of recording due to variations in resistance value. can do.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, FIG. 2 is a time chart when the thermal head shown in FIG. 2 prints using the thermal recording control system of the present invention, FIG. 3 is a time chart when printing is performed using the thermal head of FIG. 2 using a conventional thermal recording control method. DESCRIPTION OF SYMBOLS 1... Heating resistor, 2... Drive circuit, 3... Latch circuit, 4... Shift register, 25... External power supply patent applicant NEC Corporation Agent

Claims (1)

[Claims] In thermal recording in which a heating resistor array for thermal printing is divided into a plurality of groups and printing is performed sequentially for each group, when the resistance value of the heating resistor array for thermal printing is large, the number of divisions is made smaller than when the resistance value is small. A heat-sensitive recording control system characterized by: