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Thermal printhead

Imported: 23 Feb '17 | Published: 22 Oct '02

Takaya Nagahata

USPTO - Utility Patents

Abstract

A thermal printhead includes a plurality of heating elements (

6) heated by a head voltage for printing on a recording paper, and a plurality of drive IC's (

3) powered by a logic voltage for driving the heating elements (

6). The printing is performed at whatever value of the head voltage within a range from 2.7 volts through 8.5 volts. Further, the drive IC's (

3) operate at whatever value of the logic voltage within a range from 2.7 volts through 5.5 volts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a thermal printhead according to the present invention.

FIG. 2 is an enlarged view showing a principal portion of the thermal printhead in FIG.

1.

FIG. 3 is an enlarged plan view showing a heating resister of the thermal printhead in FIG.

1.

FIG. 4 is a plan view showing a relationship between an effective printing region of a heating element and a pixel.

FIG. 5 is a circuit block diagram of a drive IC provided in the thermal printhead in FIG.

1.

FIG. 6 is a timing chart of various signals related to the drive IC in FIG.

5.

FIG. 7 is a circuit block diagram showing a principal portion of a printer which incorporates the thermal printhead in FIG.

1.

Claims

1. A thermal printhead comprising:

2. The thermal printhead according to claim 1, further comprising means for setting the head voltage and the logic voltage independently of each other.

3. The thermal printhead according to claim 1, further comprising voltage varying means for varying a pulse width of the head voltage during the printing in response to variation in the head voltage.

4. The thermal printhead according to claim 1, wherein each of the heating elements has an effective print length in a sub-scanning direction, a pixel to be printed per printing datum having a print length in the sub-scanning direction, the effective print length being generally equal to an n-th of the print length, with n being a natural number not smaller than 2.

5. The thermal printhead according to claim 1, wherein each of the drive IC's incorporates a plurality of transistors connected to the heating elements.

6. The thermal printhead according to claim 5, wherein the transistors are MOS field effect transistors.

7. A printer comprising:

8. The printer according to claim 7, wherein the power supply means includes a battery.