JPH01249363A - printing device - Google Patents

Abstract

PURPOSE:To make the number of heat generating resistors generating heat at once constant and to reduce printing irregularity while increasing a printing speed, by controlling a thermal head by synthesizing printing data and printing control data. CONSTITUTION:When printing data is transmitted to a one-dot register 1, the total number of dots are counted by a control circuit 4 and, in the case of black, said dots are counted by a counter 6 and, when the number of dots reaches a preset number with due regard to the capacity of a power supply, the total dot counter value at this time is stored to be set to the punctuation of printing and this operation is repeated until the total dot counter value reaches the total number of dots. Next, the count value of the punctuation is read to be outputted to a control data forming circuit 7 and the printing control data corresponding to black data is formed to be transmitted to a register 8. The control circuit 4 indicates the generation of a printing pulse to a printing strobe circuit 5 and the drive element in a thermal head 3 is selected on the basis of the OR of printing data and printing control data by a logical circuit 2 to perform printing. This operation is repeated to finish the printing of one line.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a printing device using a thermal head used in facsimiles and the like.

BACKGROUND ART Conventionally, thermal printing using a thermal head has been widely used in printing devices such as facsimile machines, taking advantage of its ease of maintenance. The thermal head used in these printing devices has a large number of heating resistors, and transmits heat pulses to thermal paper to cause the thermal paper to develop color. If these heating resistors are made to generate heat all at once, the current supplied to the thermal head will increase, and the capacity of the power supply circuit will have to be made thicker. The current was divided and a pulsed current of a constant width was supplied to each heating resistor.

Problems to be Solved by the Invention However, the number of divisions of the thermal head described above is fixed, and even if there are many white parts in the image to be printed and there is sufficient power supply, the number of divisions of the heating resistor is always constant. Therefore, there was a problem in that the printing speed could not be increased.

The present invention solves the above problems and provides a printing device with high printing speed.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has a register for holding print data supplied to the heating resistor of the thermal head and a counter for counting the number of black data. When the number of black data counted by the counter matches the number of black data counted by the counter, the image data corresponding to the number of bits containing black data is sent from the register to the thermal head, and when the image data end signal is received, the remaining image data is transferred from the register to the thermal head. A control circuit is provided to control the sending to the head.

Function: With this configuration, the thermal head is generated by combining print data and print control data, so the number of heating resistors that generate heat at -degrees can be kept constant, and variations in the head drive current value can be reduced. In addition, when the number of heating resistors that generate heat at a time is small, the number of divisions can be reduced, and printing can be performed at high speed.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a printing control section of a printing device in an embodiment of the present invention.

In FIG. 1, 1 is a first register that holds print data, and 8 is a second register that holds control data. 2 is a logic circuit that combines the data held in the first register 1 and the second register 8 and outputs it to the thermal head 3. 5 is a print strobe circuit. 6 is a counter that counts the number of black data in print data. 4 is a control device having a microcomputer, which compares the counted value of the counter 6 with a predetermined maximum number of print dots, and when the two match, causes the data generation circuit 7 to generate control data and stores it in the second register 8. Store it.

Regarding the printing operation of the printing device configured as above,
The printing operation of the printing device in an embodiment of the present invention shown in FIG. 2 will be explained in accordance with a flowchart showing the printing operation.

It is now assumed that the printing operation of this printing device has started. First, one dot of print data is transferred to the first register 1. (Step 1) At the same time, the total number of dots in the data is counted by the control circuit 4 (Step 2), and it is determined whether the data is black or white, and if it is black, it is counted by the counter 6 (Step 3), and the result is is compared with a preset number.

Here, the preset number is the number of dots that can generate heat at one time, taking into consideration the power supply capacity. - If the number of dots that generate heat per degree is 216, then the printing paper is A4
Taking the case of a printing plate as an example, the total number of dots is 1728 dots, and the maximum number of divisions is 8. Steps 1 to 3 are repeated until the number of black dots in the image data matches the set number. If there is a match, the control circuit 4 stores the total dot counter value at the time of the match, and sets it as the first printing delimiter (step 4). At this time, the count value increases by the number of white characters. Next, the control circuit 4 determines whether the total dot counter value has reached the total number of dots, and repeats steps 1 to 4 until it reaches the total number of dots. If they match, the transfer of all data has been completed, and the control circuit has stored the delimiter position data.

Next, printing control is entered, and the control circuit 4 reads out the delimiter count value stored at the time of transfer and outputs it to the control data generation circuit 7. The control data generation circuit 7 generates print control data corresponding to black data based on the count value, and outputs the print control data to the second register 8.
(Step 5). Brother Kin's count value is 30
When it is set to 0, the generation circuit 7 generates 300 pieces of black data and 1428 pieces of white data. Also, assuming that the number of black data in the second data is 700, 300 of the previous data are white data, 400 black data are generated next, and the remaining 102
Eight pieces of white data will be generated. Thereafter, print control data is generated in the same manner. - After generating the print control data, the process proceeds to step 6, where the control circuit 4 instructs the strobe circuit 5 to generate print pulses, and the logic circuit 2 drives the thermal head by the AND of the print data and the print control data. Select the element and print.

Steps 5 and 6 are repeated until the final printing of one line is completed.

If the number of black data is 300, first 216 black data
Dots are printed, and then 84 dots of black data are printed.

In this case, the 1728 heating resistors can be divided into two blocks and printed, so 8
Printing can be performed four times faster than when printing is divided into two blocks.

When the number of black data is 800, 216 dots of black data are printed three times, and then 152 dots of black data are printed. In this case, since printing can be performed by dividing into four blocks, printing can be performed at twice the speed compared to the conventional method.

If the number of black data exceeds 1514, printing is performed by dividing into eight blocks. In this case, the printing speed is the same as that of the conventional method. However, in general, the probability that the number of black data exceeds 1514 in a total of 1728 print signals is low, and the printing speed can be improved overall.

In this way, if the number of black data is less than the total number of heat generating resistors of the thermal head minus the number of heat generating resistors that can generate heat at one time, the number of blocks into which the group of heat generating resistors of the thermal head is divided is determined. The number of blocks is smaller than that of conventional printing devices, which improves printing speed.

Effects of the Invention As described above, the present invention has a register that holds print data supplied to the heating resistor of a thermal head, and a counter that counts the number of black data, and has a predetermined number and a counter count. When the number of black data matches, the image data corresponding to the number of bits containing black data is sent from the register to the thermal head. When the image data end signal is received, the remaining image data is sent from the register to the thermal head. Since the circuit is provided, the number of divisions of the group of heating resistors is changed depending on the number of black data in the image data, resulting in an effect of increasing the printing speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a printing control section of a printing apparatus in an embodiment of the present invention, and FIG. 2 is a flowchart showing the printing operation. 1...First register 2...Logic circuit 3...Thermal head 4...Control circuit 5...Print strobe circuit 6...Counter 7...Data generation circuit 8...No. Name of second register agent: Patent attorney Toshio Nakao and one other person)

Claims (1)

[Claims] It has a thermal head equipped with a plurality of heating elements and drive elements, a register that holds print data, and a counter that counts the number of black data in the print data, and has a predetermined number and a black data counted by the counter. When the number of data matches, image data corresponding to the number of black data is sent from the register to the thermal head, and the counter again starts counting the black data in the print data, and signals the end of the image data. 1. A printing device comprising: a control circuit configured to send the remaining image data from the register to the thermal head when the image data is received.