JPH03218859A - thermal line printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to thermal line printers.

Conventional technology In recent years, thermal line printers are required not only to print at high speed but also to have high resolution.The number of heating elements in thermal line heads has increased, and the amount of data to be processed has also increased proportionately. There is a strong need to process large amounts of data.

A conventional thermal line printer will be explained below. In the conventional graphic data processing method, as shown in FIG. 5, 1-byte print data input in parallel from the host system is buffered inside the microcomputer 11 in order to control the thermal history of the thermal line head. 12, microcomputer 1
1 performs software calculation and parallel-to-serial conversion inside the microcomputer 11 and transfers the serial data from the port of the microcomputer 11 to the thermal line head 13, or as shown in Fig. 6, 1-byte data input in parallel from the host system Print data to thermal line head 13
In order to control the thermal history of the microcomputer 11, the parallel data is transferred from the port of the microcomputer 11 to the parallel-to-serial converter circuit 14, and then the clock output from the microcomputer 1l is transferred from the port of the microcomputer 11 to the parallel serial converter circuit 14. The converted serial data was transferred to the thermal line head 13 using the .

Problems to be Solved by the Invention However, among the conventional configurations described above, the graphic data processing method using FIG. When doing so, the data is transferred in synchronization with the internal clock of the microcomputer, but since the internal clock frequency of this microcomputer is low, the graphic data processing time becomes long.

Furthermore, in the graphic data processing method using FIG. 6, the clock frequency output from the microcomputer is low, so the processing time for graphic data becomes long. What is common to both of the above methods is that the graphic data input from the host system is once taken into the microcomputer and then output to the thermal line head, which wastes time in processing the graphic data.

In order to solve the above-mentioned problems, the present invention directly transfers parallel graphic data input from a host system to a parallel-to-serial conversion circuit without importing it into the microcomputer, and synchronizes it with a high-frequency external clock to convert it into serial data. The purpose of the present invention is to provide a thermal line printer that can realize high-speed printing of graphics by transferring data to the thermal line head while controlling the thermal history of the thermal line head using hardware.

Means for Solving the Problems In order to achieve the above object, the thermal line printer of the present invention receives data (character code data and graphic data) output from the host system in its control circuit, and the microcomputer receives the data (character code data and graphic data) output from the host system. There is a buffer that retains the data until it is read, and the parallel graphic data taken out from the buffer or the character code data taken out from the buffer is once transferred to a microcomputer, and the parallel character font data converted there is serialized. A parallel-to-serial conversion circuit converts the data into data and transfers it to the thermal line head, and the microcomputer's read signal (RD signal) is connected to the parallel-to-serial conversion circuit as a latch pulse, and when the microcomputer reads the data, the data is converted into graphic data. Then, a direct latch control circuit that simultaneously holds data in the parallel-to-serial conversion circuit, and a high-frequency shift clock to convert parallel graphic data or character font data held in the parallel-to-serial conversion circuit to serial data at high speed. an external oscillator circuit that generates the shift clock, a shift clock control means that controls driving and stopping of the shift clock, a parallel-serial conversion number monitoring circuit that monitors the number of serial data output from the parallel-serial conversion circuit, and a current data and past This configuration includes a thermal history correction circuit that stores data and performs thermal history correction using hardware.

Function: According to the present invention, character code data output from a host system is taken into a microcomputer using an existing method, converted into character font data, subjected to parallel-to-serial conversion, and transferred to a thermal line head while controlling thermal history. On the other hand, graphic data output from the host system is directly converted from parallel to serial without being imported into the microcomputer, and then transferred to the thermal line head while being corrected for its thermal history. This reduces graphic data processing time and speeds up graphic printing. It is possible to obtain high-speed performance, and also to enable high-resolution graphic printing.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention.
is a microcomputer, 2 is a buffer that holds character code data and graphic data input from the host system, and 3 is a parallel/serial that converts parallel graphic data and parallel character font data output from microcomputer 1 into serial data. a conversion circuit; 4 is an external oscillation circuit that generates a shifted clock for conversion in the parallel-to-serial conversion circuit 3; 5 is an 8-bit monitoring counter that monitors the number of data converted from parallel to serial; 6 is a parallel-to-serial conversion circuit; A thermal history correction circuit adds thermal history correction to the serial data converted by the circuit 3 and transfers the thermal history correction data to the thermal head 7, 8 is an OR gate, and 9 and 10 are AND gates. Further, the RD signal is connected to a data latch pulse input section of the parallel-serial conversion circuit 3.

The control circuit of the thermal line printer configured as described above will be explained below using the configuration diagram in FIG. 1 and the overall operation flowchart in FIG. 2.

First, it is determined whether the data input from the host system is character code data or graphic data.
Microcomputer 1 for character code data
One line is captured internally, and then the character code data is converted into character font data and transferred to the parallel-serial conversion circuit 3. Next, the shift clock signal generated from the external oscillation circuit 4 is transferred to the parallel-to-serial conversion circuit 3, and the shift clock is stopped after 8 clocks have been transferred, thereby serially transferring the character font data to the thermal history correction circuit 6. The thermal history correction circuit 6 transfers the serial data (current data) to the thermal line head 7, and transfers AND data of the current data and data obtained by inverting the previous data to the thermal line head 7. and the operation of transferring the AND data of the current data and the data obtained by inverting the two past data to the thermal line head 7.
By transferring one line of each of the three types of data during line color development, the thermal line head 7
It is possible to correct the heat accumulation of the heating element (see FIGS. 3 and 4).

Second, if the data input from the host system is graphic data, simply by reading it into the microcomputer 1, the graphic data is automatically transferred to the parallel-serial conversion circuit 3 and latched. That is, data is automatically transferred to the parallel-serial conversion circuit 3 and latched by the RD signal of the microcomputer 1. From here on, the process can be carried out in the same manner as the character font data processing method described above.

According to the configuration of the above embodiment, by performing head thermal history correction using hardware, there is no need to read graphic data once into the microcomputer and calculate and create head thermal history correction data within the microcomputer. When the microcomputer simply reads the graphic data, the data is automatically latched into the parallel-to-serial converter circuit, and the shifted clock to the parallel-to-serial converter circuit uses a high-frequency clock output from an external oscillation circuit. This allows processing time to be shortened.

Effects of the Invention As described above, the present invention corrects the thermal history of the head using hardware, thereby converting the data from parallel to serial by simply importing graphic data input from the host system into the microcomputer. The data is transferred directly to the circuit and parallel-to-serial conversion is performed using a high-frequency external clock. At the same time, data can be transferred to the thermal line head while correcting the thermal history of the head, which has the excellent effect of high graphic printing quality and high-speed printing. It is possible to realize a thermal line printer.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a thermal line printer according to an embodiment of the present invention, Fig. 2 is a flowchart for explaining the operation of the printer, Fig. 3 is a timing diagram of data transfer to the head, and Fig. 4 is a head An explanatory diagram showing the applied pulse width determination algorithm, Figure 5 shows conventional graphic data processing in which thermal history correction data is calculated and created inside the microcomputer, the data is converted from parallel to serial inside the microcomputer, and then transferred to the thermal line head. The system configuration diagram, Figure 6, calculates and creates thermal history correction data inside the microcomputer, transfers the data to an external parallel-to-serial converter circuit, and transfers the data to the thermal line head using the shift clock output from the microcomputer. 1 is a configuration diagram of a conventional graphic data processing method for transferring . 1...Microcomputer, 2...
Buffer, 3...Parallel-serial conversion circuit,
4...External oscillation circuit, 5...8-bit monitoring counter, 6...Thermal history correction circuit, 7.
・・・・・・Thermal line head, 8・・・・・・OR
Circuit, 9, 10...AND circuit. Side ÷ Nu−. ．． 'tKl}4 Figure 2 Figure 4 To the 7th CL of Figure Ward''<1 toku

Claims (1)

[Claims] A microcomputer that has a function to perform graphic printing, a parallel-to-serial conversion circuit to which the data is transferred at the same time as this microcomputer reads graphic data, and which is controlled by a control signal from the microcomputer, and this parallel-to-serial conversion circuit. 1. A thermal line printer comprising: a circuit for transmitting data obtained by adding thermal history correction to graphic data converted by the above to a driver of a thermal line head.