Printer, printing method for printer, and program

Patent metadata

Field	Value
Publication number	US-12466195-B2
Application number	US-202218267393-A
Country	US
Kind code	B2
Filing date	May 26, 2022
Priority date	Jun 7, 2021
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

A printer is configured to print on a print medium having a thermal color developing layer and includes: a thermal head having a plurality of heating elements that are arranged in a line; and a processor configured to: set a first application period of a pulse of energizing current, during a scanning line time for one line, the pulse of energizing current applying thermal energy that causes the thermal color developing layer to develop color, to the plurality of heating elements, correct a length of the first application period, which is set by the processor, based on an image to be printed, and determine print speed to be applied in printing the whole image at a constant speed, by extending the scanning line time so as to contain a maximum length of the first application period that has been corrected by the processor.

First claim

The invention claimed is:

1 . A printer being configured to print on a print medium having a thermal color developing layer, the printer comprising:
a thermal head having a plurality of heating elements that are arranged in a line; and a processor configured to:
set a first application period of a pulse of energizing current for applying to the plurality of heating elements during a scanning line time for one line to cause the thermal color developing layer to develop color,
correct a length of the first application period based on an image to be printed,
determine a print speed to be applied in printing the whole image at a constant speed by extending the scanning line time so as to contain a maximum length of first application periods that have been corrected by the processor, and
further correct the length of the first application period so that a first ratio of the first application period of the pulse of energizing current during the scanning line time before the processor determines the print speed and a second ratio of the first application period of the pulse of energizing current during the scanning line time after the processor determines the print speed will be the same.

2 . The printer according to claim 1 , further comprising:
a storage configured to store data of the length of the first application period of the pulse of energizing current in the scanning line time for one line with respect to each of a plurality of print speeds that are set so as to increase by a predetermined first increment of speed, wherein the processor is configured to determine the print speed by adjusting one of the by plurality of print speeds by a second increment of speed that is less than the predetermined first increment of speed.

3 . The printer according to claim 2 , further comprising:
a battery configured to supply power to the thermal head, wherein the processor is configured to correct the length of the first application period based on voltage of the battery.

4 . The printer according to claim 2 , further comprising:
a temperature measuring unit configured to measure temperature of the thermal head, wherein the processor is configured to correct the length of the first application period based on the temperature of the thermal head.

5 . The printer according to claim 2 , wherein:
the processor is further configured to:
set a second application period of a pulse of energizing current for applying to the plurality of heating elements during the scanning line time for the one line, the pulse of energizing current insufficient to cause the thermal color developing layer to develop color,
correct lengths of the first application period and the second application period based on the image, and
determine the print speed to be applied in printing the whole image at a constant speed, by extending the scanning line time so as to contain maximum lengths of the first application periods and the second application periods that have been corrected by the processor.

6 . The printer according to claim 1 , further comprising:
a battery configured to supply power to the thermal head, wherein the processor is configured to correct the length of the first application period based on voltage of the battery.

7 . The printer according to claim 1 , further comprising:
a temperature measuring unit configured to measure temperature of the thermal head, wherein the processor is configured to correct the length of the first application period based on the temperature of the thermal head.

8 . The printer according to claim 1 , wherein:
the processor is further configured to:
set a second application period of a pulse of energizing current for applying to the plurality of heating elements during the scanning line time for the one line, the pulse of energizing current being insufficient to cause the thermal color developing layer to develop color,
correct lengths of the first application period and the second application period based on the image; and
determine the print speed to be applied in printing the whole image at a constant speed, by extending the scanning line time so as to contain maximum lengths of the first application periods and the second application periods that have been corrected by the processor.

9 . A printing method for a printer that comprises a thermal head that has a plurality of heating elements arranged in a line, the printer being configured to print on a print medium having a thermal color developing layer, the printing method comprising:
setting a first application period of a pulse of energizing current for applying to the plurality of heating elements during a scanning line time for one line to cause the thermal color developing layer to develop color; correcting a length of the set first application period based on an image to be printed; determining a print speed to be used in printing the whole image at a constant speed by extending the scanning line time so as to contain a maximum length of first application periods that have been corrected; and further correcting the length of the first application period so that a first ratio of the first application period of the pulse of energizing current during the scanning line time before the print speed is determined and a second ratio of the first application period of the pulse of energizing current during the scanning line time after the print speed is determined will be the same.

10 . A non-transitory recording medium containing a program, the program being configured, when installed in a printer to cause a computer to execute a predetermined method, the printer comprising a thermal head that has a plurality of heating elements arranged in a line, the printer being configured to print on a print medium having a thermal color developing layer, the predetermined method comprising:
setting a first application period of a pulse of energizing current for applying to the plurality of heating elements during a scanning line time for one line to cause the thermal color developing layer to develop color, correcting a length of the set first application period based on an image to be printed; determining a print speed to be used in printing the whole image at a constant speed by extending the scanning line time so as to contain a maximum length of first application periods that have been corrected; and further correcting the length of the first application period so that a first ratio of the first application period of the pulse of energizing current during the scanning line time before the print speed is determined and a second ratio of the first application period of the pulse of energizing current during the scanning line time after the print speed is determined will be the same.

Assignees

• Sato Holdings Kk
• Sato Kk

Inventors

• Hirafuji Takuma

Classifications

• B41J2/04541

  Specific driving circuit · CPC title

• B41J2/36

  Print density control · CPC title

• B41J2/37 Primary

  by compensation for variation in current · CPC title

• B41J2/365

  by compensation for variation in temperature · CPC title

• B41J2/32

  using thermal heads · CPC title