JPS637951A - Thermal recording control system - Google Patents

Abstract

PURPOSE:To obtain a thermal recording system capable of preventing the variation in the voltage applied to a heat generator and suppressing the irregularity of printing recording, by counting the number of black or white pixels simultaneously recorded on the basis of an image signal and correcting the pulse width of a printing pulse corresponding to the number of the pixels. CONSTITUTION:A black pixel counting means 24 receives a signal showing the number of a predetermined printing block from a printing pulse output means 2 to count the number of black pixels in the printing block corresponding to said number and a signal showing the number of black pixels is outputted to a printing pulse width correction means 5. The printing pulse width correction means 5 to which the signal is inputted corrects the pulse width of a printing pulse so as to set off the variation in the voltage of the power source of a heat generating element 14 generated by the variation in the voltage of a power source. By this method, effect due to the variation in the voltage of the power source on each heat generating element 14 of a thermal recording head is suppressed.

Description

[Detailed Description of the Invention] [Summary] The present invention calculates the number of black or white pixels recorded simultaneously based on an image signal (using a pixel number counting means), calculates the load variation, and calculates the load variation. The pulse width of the print pulse is corrected (by the p-stage print pulse correction) so as to offset fluctuations in the power supply voltage, thereby preventing density unevenness in thermal recording.

[Industrial application field]

The present invention relates to a control method for thermal recording in a computer output device, a word processor, a facsimile receiver, etc., and more specifically, the present invention relates to a control method for thermal recording in a computer output device, a word processor, a facsimile receiver, and the like. The present invention relates to a thermal recording control method in which a recording is obtained by coloring a thermal recording paper placed in contact with a thermal recording head, using a printing pulse output means for applying pulses.

[Conventional technology]

Conventionally, in a thermal recording control system in a facsimile receiver or the like, as shown in FIG.
Accordingly, in addition to the thermal recording head 33 constituted by a heating element, recording was obtained by coloring the thermal recording paper placed in contact with the thermal recording head 33. Furthermore, a power supply voltage fluctuation adjustment circuit 3 attached to the power supply 34 adjusts the power supply voltage fluctuation due to load fluctuation.
5 was used to keep it within a certain range.

This is because thermal recording is performed using Joule heat generated by the creative element, so the load varies greatly depending on the number of black pixels.
This is to prevent unevenness in the density of printed records due to fluctuations in the output voltage from the power source and, ultimately, in the voltage supplied to the heating element.

[Problem that the invention seeks to solve]

By the way, in the past, a power supply voltage adjustment circuit 35 is used to prevent the occurrence of uneven printing records, but the power supply voltage adjustment circuit 35 generally has a complicated configuration and is expensive, and also has a large fluctuation range. The problem was that it was difficult to make it sufficiently small.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a heat-sensitive recording method that can sufficiently suppress unevenness in print recording of heat-sensitive recording using a simple configuration.

[Means for Solving the Problems] As shown in FIG. 1, the present invention provides a recording control means 1 for outputting an image signal and a thermal recording head 3 composed of a heating element, and a printing pulse corresponding to the image signal. a pixel number counting means 4 for counting the number of black or white pixels simultaneously recorded based on 1m numbers in a thermosensitive recording control system having a printing pulse output means 2 for adding a number of black or white pixels; A printing pulse width correction means 5 is provided for correcting the pulse width of the printing pulse according to the printing pulse width.

[Effect]

As shown in FIG. 1, when the recording control means 1 outputs an image signal, the pixel number counting means 4 counts the number of black or white pixels to be simultaneously printed and recorded based on the image signal.

A black pixel is obtained on the thermosensitive recording paper by the heat generated by the heat generating element, and the heat generated is due to Joule heat generated when a current flows through the resistance of the heat generating element. Therefore, the load on the thermal recording pad 3 is determined by the number of black or white pixels to be recorded simultaneously. By counting the number of black or white pixels, Rad3
load fluctuations can be detected.

Variations in the load on the thermal recording head 3 cause variations in the voltage supplied from the power supply, and the printing pulse width correction means 5 performs printing so as to offset variations in the power applied to the heating elements caused by variations in the supply voltage. Correct the pulse width of the pulse.

〔Example〕

A thermal recording method according to an embodiment of the present invention will be explained in the case of a facsimile receiver. Reference numeral 11 denotes a photoelectric conversion means on the facsimile transmitter side, which converts a transmitted image divided into pixels by scanning into an electrical signal. The transmission path 12 is for transmitting the electrical signal to the recording control means 1 on the facsimile receiving side. The recording control means 1 converts the electric signal into an image signal suitable for recording. The printing pulse output means 2 receives the image signal and outputs one printing pulse according to the image signal.
For example, the voltage is applied to the image signal drive switch 16 and block selection switch 17 of the thermal recording head 13 of the parallel recording circuit. Here, the parallel recording circuit means that the number of pixels for one scan is, for example, L, and is divided into n printing blocks (
L))n) Each printing block is 1m (L+n; usually 25
The heating elements 14 of 6) are connected in parallel, and each printing block is simultaneously recorded by the block selection switch 17. 15 is a separation diode, and 18 is a power source for the thermal recording head.

24 is a black pixel counting means as the pixel counting means 4;
It counts the number of black pixels for each print block recorded at the same time, and outputs the number of black pixels according to the print block number instructed by the print pulse output means 2.

5 is a printing pulse correction means, which calculates the black pixel number ratio (=number of black pixels in printing block/number of pixels in printing probe 2 xi oo
%: Load factor = Average demand power / Maximum demand power x 100%)
It outputs a pulse correction coefficient for correcting power supply voltage fluctuations expected from the change in power supply voltage, and can be easily configured using a ROM or the like. As shown in FIG. 3, the correction is performed by determining the pulse width so as to have a correction value that compensates for the decrease in power due to the increase in the load factor, for example, by using a conversion table created in advance. is a storage means such as a shift register, which temporarily stores image signals.

According to this embodiment, the electrical signal transferred from the facsimile transmission side is converted into an image signal by the recording control means l. The print pulse output means 2 receives the image signal and applies a print pulse corresponding to the image signal to the block selection switch 17 of a print block with a predetermined number of the recording head 13 and the image signal drive switch 16 of a predetermined pixel. , are closed to cause the heating element 14 corresponding to the image signal to generate heat.

At this time, the black pixel number counting means 2 receives a signal from the printing pulse outputting means 2 to display the number of the predetermined printing block.
4 counts the number of black pixels in the print block corresponding to the number, and outputs a signal to the print pulse width correction means 5 to display the number of black pixels. The printing pulse width correction means 5, which receives the signal, adjusts the pulse width of the printing pulse according to the black pixel number ratio (load ratio) so as to offset the TL source voltage fluctuation of the heating element 14 caused by the fluctuation of the power supply voltage. Correct.

By this, each firing of the thermal recording head 13? JI! Element 1
4, the influence of fluctuations in power supply voltage can be suppressed.

Note that in the above embodiments, the number of white pixels may be counted instead of the number of black pixels.

〔Effect of the invention〕

As is clear from one or more configurations, the present invention accurately detects the load fluctuation using a pixel counting means even if the power supply voltage fluctuates due to the load fluctuation of the heating element of the thermal recording head based on the image signal, Since the printing pulse width correction means corrects the pulse width of the printing pulse to remove the load fluctuation and applies the printing pulse to the heating element, unevenness in printing temperature due to load fluctuation can be corrected with a simple configuration. It can be removed reliably and inexpensively.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a block diagram showing correction of the 1-character pulse width correction means, and Fig. 4 is a block diagram showing a conventional example. It is. l... Recording control means 2... Print pulse output means 3.13... Thermal recording head 4.24... (Black) pixel number counting means 5... Print pulse width correction means

Claims (1)

[Scope of Claims] Comprising a recording control means (1) for outputting an image signal, and a print pulse output means (2) for applying a print pulse to a thermal recording head (3) constituted by a heating element in accordance with the image signal. In the thermal recording control system, a pixel number counting means (4) counts the number of black or white pixels recorded simultaneously based on an image signal, and a pulse width of the printing pulse is controlled according to the number of black or white pixels. A thermal recording control method characterized by comprising a printing pulse width correction means (5) for correction.