JPS59149460A - Thermal recording system - Google Patents

Abstract

PURPOSE:To prevent unevenness of recording density by controlling pulse width at intervals of one line and performing recording operation when a heating element is at normal temperature, and starting the control over the recording density at every paper from the following page when the temperature of the element exceeds its upper-limit protection temperature. CONSTITUTION:When the recording of a thermal recording device is started, the temperature of the heading element is detected by a temperature detection part 1. A control part 2 compares the detection information with the upper-limit temperature provided for protecting the heating element; when the detected temperature is lower than the upper-limit temperature, the pulse width corresponding to the detected temperature is transmitted to a recording part 3 to conduct electrically the heating elemnt so that recording temperature is held constant, and one-line information is recorded with the pulse width, thereby performing the recording which the pulse width is varied at intervals of one line. When the element temperature exceeds the upper-limit temperature, the recording is carried on with the constant pulse width up to the page end and the pulse width is reduced from the next page to decrease the recording density; and the heating element is cooled to prevent unevenness of recording density.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a thermal recording system, and more particularly to a thermal recording system using a dual head or the like.

2. Description of the Related Art Recording apparatuses that perform printing using a thermal recording method using a thermal head are widely used.

A known method for thermal control in this type of recording device is to control the pulse width of the pulse that controls the heat generating element in the thermal head, thereby controlling the energization time to the heat generating element, thereby controlling the heat of the heat generating element. There is.

When performing heat control using such a control method, there are two methods for controlling the pulse width as follows.

One method is to control the pulse width in two large sections, such as for each recorded page, and the other method is to control the pulse width for each recorded line.

When a method that controls the pulse width in a wide interval like the first method is adopted, for example, when recording an image that generates a large amount of heat because the pulse width for that page is determined at the beginning of each page (the second method is , a difference in density occurs between the leading edge and the trailing edge of the page.In other words, even if the temperature of the heating element rises, the pulse width does not change (- resulting in a difference in density).

Furthermore, if one page is long, the temperature rise of the heating element is not controlled, which may lead to damage to the heating element.

On the other hand, in the second method, which controls the pulse width for each line, it is possible to control the a difference between the leading edge and the trailing edge of the page so that the 41 degrees of the heating element is -4 degrees. If the temperature of the heating element is controlled by suppressing the pulse width as a protection measure, a difference in density will occur line by line, and the recorded image will not be smeared and the recording quality will deteriorate. Put it away.

Purpose The present invention has been made in order to eliminate the drawbacks of the conventional technology as described below. It is an object.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail based on the embodiments shown in the drawings.

FIG. 1 is a block diagram showing the basic configuration of the present invention. In FIG.

A pulse width corresponding to the temperature detected by the control section 2 is determined, and this is transmitted to the recording section 3, and the heating element is energized with a pulse width of 7 to record.

A specific pulse width control method will be explained based on the flowchart shown in FIG.

That is, when the apparatus starts, it is determined in step S1 whether or not recording is to be started, and if it is determined that recording is to be started, one recording is started from the top of the page in step S2. When this recording is started, the temperature of the heating element is detected by the temperature detection section 1 in step 53 (-). Then, the process proceeds to step S4, where the information from the temperature detection section 1 and the temperature of the heating element are detected by the temperature detection section 1. If it is determined that the upper limit temperature has not been reached, the process proceeds to step S5 to keep the recorded temperature constant (=, pulse corresponding to the detected temperature in 7). The width is determined. Next, the process proceeds to step S6, where the determined pulse width is transmitted to the recording unit 3 (2), the heating element is energized, and information for one life is recorded with a pulse width of 7c.

Next, the process advances to step S7, and it is determined whether or not the recording for one line has been completed. If it is not finished, the process returns to step S2, and if it is finished, the process proceeds to step S9, where it is determined whether all recording has been completed, and if not, the next page is recorded. I'm going to move on.

If it has ended, the control operation ends now.

On the other hand, in step S4, if it is determined that the temperature of the element has reached the upper limit (-) (second is step S10
It is determined that it is difficult to record information without image unevenness using Noculus control for each line, and it is possible to record information and cool the heating element, and performs recording with a constant pulse width until the end of the page ( Step 511). and step S
Return to ε.

In this way, the pulse width is controlled for each line,
The concentration difference force S/A is controlled so as not to be the same between the leading edge and the trailing edge of the recorded page, and the temperature of the heating element is kept at or above the reference temperature (if repeated twice (the second is from the next page)), and the pulse width is control)
From control per line to control per page H
, H'4'' and reduce the pulse width to reduce the recording density and cool the heating element, it is possible to suppress the temperature rise of the heating element and prevent uneven recording density.

Effects As is clear from the above explanation, according to the present invention (2), the pulse width control method, which is equivalent to the energization time to the heating element, is set at an upper limit or a reference temperature, and when the temperature is below the upper limit, it is controlled for each line. Since a method is adopted in which control is performed page by page when the temperature is above the upper limit temperature, damage to the heating element can be prevented and recording density unevenness within a page can be controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control circuit illustrating an embodiment of the present invention, and FIG. 2 is a flowchart illustrating a specific control operation. 1... Temperature detection section 2... Control section 3...
Recording department

Claims (1)

[Claims] When the temperature of the heating element is normal, the pulse width is controlled and recorded for each line, and if the temperature exceeds the upper limit temperature considered necessary to protect the element, the next page will be displayed. A thermal recording method characterized by controlling recording density for each page.