JPS6078769A - Thermal recording system - Google Patents

Abstract

PURPOSE:To enable printing density to become constant and uniform, by changing the amplitude of a pulse applied to a resistor element by storing correction data corresponding to the resistance value of the resistor element. CONSTITUTION:A non-volatile ROM is used as a thermal resistance value variation correcting part 18 and the irregularity value of the resistance value of a thermal head 7 can be read therein and the writing of data can be performed from an operation part 2 while a line density correcting part 19 has function for correcting the amplitude of an applied pulse. When a receiving control part 12 receives receiving data, the data of a table 13 is read to correct the amplitude of the applied pulse while the correction of the amplitude of the applied pulse corresponding to the variation in the resistance value of the head 7 is performed on the basis of the data 18 of the correcting part 19 and the correction of the adapted pulse is further performed by the correcting part 19. A control part 12 applies the pulse subjected correction to the head 7 and, at the same time, performs the rotary control of a pulse motor 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a thermal recording system, and particularly to a method of controlling a thermal head.

(bl Technology background) In recent years, facsimile machines, printers, etc. have become smaller and lighter, have simpler structures, lower noise, lower prices, and improved operability. As an effective method, it has come to be widely used for image recording.

However, there are still problems with the price, quality, and reliability of the thermal head itself, and there is still plenty of room for improvement in printing quality, and further research and development is underway.

(C1 Prior Art and Problems The conventional method will be explained below with reference to FIGS. 1 to 3.

FIG. 1 is a perspective view showing an embodiment of a facsimile device to which the present invention is applied, FIG. 2 is a control block diagram of the receiving section of the facsimile device, and FIG. 3 is a correction sequence for the pulse width applied to the thermal head. FIG.

As shown in FIG. 1, the facsimile machine has a main body 1, an operation section 2, an insertion section 3 for sending originals, and an ejection port 4.
After the transmission contents of the transmission document inserted from the insertion section 3 are read in the apparatus, it is discharged from the discharge port 4 and is sequentially stocked in the document stacker 7 5.

On the other hand, after receiving information is recorded on the recording paper within the apparatus, the recording paper is ejected to a recording paper stacker 6 on the back in an orderly manner.

The thermal recording method applied to the present invention, as shown in FIG. 2, brings a thermal head 7 into contact with thermal paper 8 and applies thermal energy generated by the thermal head 7 to the thermal paper 8.
Printing is performed by the chemical coloring reaction of the thermal paper 8, and as shown in the figure, - lines are simultaneously printed in the main scanning direction (arrow A direction) of the thermal paper 8 depending on the image signal sent to the thermal head 7. This is what we do. The print density is determined by the amount of heat that the thermal head 7 gives to the thermal paper 8, and the amount of heat is expressed by the following equation.

j=pxT=vsiRXT where j is the amount of heat, P is the power (watts), T is the application time,
R is the resistance value of the thermal head, and ■ is the voltage.

Therefore, if the voltage (2) is constant and the resistance value R of the thermal head 7 varies, it is necessary to correct the time for applying power to the thermal head 7 in order to obtain a constant NJ.

Also, when the amount of information is large and the repetition period for -line is small, the temperature of the heat generating part of the thermal head 7 decreases slowly, whereas when the amount of information is small and the repetition period is large, the temperature of the heat generating part decreases slowly. Power P applied to the thermal head 7 to speed up
It is necessary to increase the time T.

Note that the application time T in this case refers to an applied pulse.

To explain with reference to the figure, the signal transmitted through the transmission path 9 is demodulated by the modulation/demodulation device 10, and if the data is band-compressed, the data is expanded by the data decompression unit 11 and sent to the reception control unit 12. Send.

The reception control unit 12 controls the pulse width applied to the thermal head 7 through the data bus 17 and the pulse motor for feeding the thermal paper 8 according to table elements recorded in a table 13 based on input data. 14 is controlled via an input/output control device 15.

The contents of Table 13 are based on the above-mentioned reasons, and in order to achieve a constant and uniform print density on the thermal paper 8, the characteristics of the thermal paper 8 to be used and the different resistance values for each manufacturing loft of the thermal head 7 are dealt with. The application pulse widths corresponding to the repetition period of the - line and the temperature fluctuation conditions of the thermal head 7 detected by the thermistor 16 attached to the thermal head 7 are shown in the table in FIG. As shown
It is written using ROM etc.

In other words, the table shows the repetition period of one line and the thermal head 7.
The relationship between temperature and applied pulse width is shown.

When printing is performed using the receiving section having such a configuration, the receiving control section 12 first determines the repetition cycle of the first line by using the basic pulses of the pulse motor 14 for feeding the thermal paper 8 from the start of recording to the end of recording. It is detected as time by counting. Then, the reception control unit 12 determines the applied pulse width based on the detected data and the table data read from the table 13 force ζ, and controls the thermal head 7 from the next line onward.

However, in such a configuration, when it becomes necessary to replace the thermal head 7, for example, the thermal head 7 has a relatively large variation in resistance value from lot to lot due to production, and conventional methods have been used to deal with this. Therefore, there has been a drawback that the printing density varies depending on the production lot of the device.

Also, depending on the transmission mode, on the receiving side, the sub-scanning direction (arrow B
7. When the scanning line densities in different directions (directions) are different, for example, dense.
In the case of 7 lines/tsuru and 3.85 lines/double resistance, the latter print density is of course lighter and different from the former.

Therefore, as a method for obtaining a constant density, for example, in the case of 3.85 lines/in, after the printing of the - line is completed, the same printing is repeated once again for another - line below the previous line, so-called double writing.

In such a case, there is a disadvantage that time is lost, and if writing is not performed twice, there is a disadvantage that the concentration is different from that of 7.7 pieces/tuna.

Tdl OBJECTS OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and to provide a thermal recording system that does not cause uneven printing.

(e) Structure of the Invention In order to achieve the above object, the present invention provides a thermal recording method that records a plurality of dots using a plurality of resistance elements, and the resistance value of each resistance element is a means for inputting corresponding correction data, a storage means for storing the input correction data, and a means for changing the width of the applied pulse applied to the resistive element according to the stored correction data, According to the print density determined, correction data is inputted to change the print density.

(fl Embodiment of the Invention An embodiment of the invention will be described below with reference to FIGS. 4 and 5.

FIG. 4 is a control block diagram of the receiving section of the facsimile apparatus according to the present invention, and FIG. 5 is a diagram showing a correction sequence for the pulse width applied to the thermal head of the present invention.

In the figure, 18 is a thermal head resistance value fluctuation correction section, 19
is a linear density correction section. Items with the same reference numeral are the same throughout the design.

As shown in FIG. 4, in the present invention, a thermal head resistance value fluctuation correction unit 18 using a nonvolatile ROM (EEFROM) or the like is added, which can read the variation value of the resistance value of the thermal head 7. This is what I did. Data can be easily written to the thermal throat resistance value fluctuation correction section 18 from the operation section 2.

Therefore, it has become possible to easily write the resistance value of the thermal head 7 to be attached when manufacturing or maintaining the facsimile machine.

In addition, the linear density correction unit 19 has a rough received scanning line density, for example, 3.
．． In the case of 85 lines/Nm, the applied pulse width can be largely corrected so that the print density is not much different from the case of 7.7 lines/Nm without performing the above-mentioned double writing.

By doing so, the reception control section 12 of the facsimile machine can
When the received data is received, the table data is read out as before to correct the applied pulse width, and the resistance value of the thermal head 7 is adjusted based on the data newly written in the thermal head resistance value fluctuation correction section 18 according to the present invention. Correct the applied pulse width for the variation. Furthermore, the scanning line density is coarser (
3.85 fins/fin), the linear density correction section 19 performs an appropriate pulse width correction.

The reception control section 12 applies the above-corrected pulses to the thermal head 7 via the data bus 17 and the input/output control device 15, and at the same time controls the rotation of the pulse motor 14.

(gl As explained in detail about the invention, by applying the thermal recording method of the present invention, it is possible to maintain a constant and uniform recording speed without being affected by variations in the resistance value of the thermal head or by coarse or dense scanning line density. It is now possible to obtain high printing density.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a facsimile device to which the present invention is applied, FIG. 2 is a control block diagram of the receiving section of the facsimile device, and FIG. 3 is a correction sequence for the pulse width applied to the thermal head. Figure 4 is a control block diagram of the receiving section of the IJ device according to the present invention;
FIG. 5 is a diagram showing a correction sequence of 111 widths in terms of the voltage applied to the thermal head of the present invention. In the figure, 2 is a scanning section, 7 is a thermal gutter, 8 is a thermal paper, 9 is a transmission line, 10 is a modulation/demodulation device, 11 is a data expansion section, 12 is a reception control section, 13 is a table, 14 15 is a pulse smoke, 15 is an input/output control device, 16 is a thermistor, 17 is a data node, 1B is a thermal head resistance value fluctuation correction section, and 19 is a spring density correction section. Tatebuzu 2nd prisoner 4Z

Claims (1)

[Claims] A thermal recording method for recording a plurality of dots using a plurality of resistance elements, comprising means for inputting correction data according to each resistance value of the resistance elements, and a storage means for storing the input correction data. and a means for changing the width of the applied pulse applied to the resistive element according to the stored correction data, and inputting the correction data to change the print density according to the recorded print density. A thermosensitive recording method.