US 5,473,355 A · Thermal printing method and thermal printer

Abstract

Half-tone image data and character image data are discriminated from each other with reference to discrimination data, and are stored separately from each other. In accordance with the image to be printed, one of a character print table and a half-tone print table is selected. In accordance with the result of comparison of the character image data with comparison data read from the character print table, characters are recorded using two kinds of character dot print patterns for recording a dot in the whole area of an associated pixel and for recording no dot. Half-tone images are recorded in the area gradation method using half-tone dot print patterns in accordance with the result of comparison of the half-tone image data with comparison data read from the half-tone print table. One pixel is divided into a plurality of sub-lines. The recording of the characters is performed at intervals of N sub-lines, N is an integer. The recording of the half-tone images is performed at intervals of one sub-line.

Claims17

Dependent claims

A thermal printing method using a plurality of heating elements disposed in a first direction, said heating elements being moved relative to a recording medium in a second direction perpendicular to said first direction so as to simultaneously record dots in a plurality of pixels disposed in said first direction on said recording medium, each of said pixels being constituted by a plurality of sub-lines and a tonal gradation being reproduced by changing the number of said sub-lines having a dot recorded thereon within each of said pixels, said thermal printing method comprising the steps of:

discriminating based on discrimination data whether image data inputted thereto is half-tone image data or character image data;
storing said half-tone image data in a first memory;
storing said character image data in a second memory;
printing a half-tone image in accordance with said half-tone image data in a first dot print mode;
and
printing a character image in accordance with said character image data in a second dot print mode which differs from said first dot print mode.

3 more elements

A thermal printer having a plurality of heating elements disposed in a first direction, said heating elements being moved relative to a recording medium in a second direction perpendicular to said first direction so as to simultaneously record dots in a plurality of pixels on said recording medium, each of said pixels being constituted of a plurality of sub-lines and a tonal gradation being reproduced by changing the number of said sub-lines having a dot recorded thereon within each of said pixel, said thermal printer comprising:

discrimination means for discriminating, based on discrimination data, whether image data inputted thereto is one of half-tone image data and character image data;
a first memory for storing said half-tone image data;
a second memory for storing said character image data;
reading means for selecting one of said first memory and said second memory depending on whether an image to be printed is a half-tone image or a character image, and reading said selected one of said first and second memories;
a counter for detecting a position of one of said sub-lines on which said heating elements can record dots at present;
a dot print pattern look-up table including a half-tone print table for outputting a first sequence of comparison data and a character print table for outputting a second sequence of comparison data which is different from said first sequence of comparison data, one of said half-tone print table and said character print table being selected in accordance with said image to be printed, and addressed by the sub-line position detected by said counter;
a comparator for comparing one of said first and said second sequence of comparison data respectively with one of said half-tone image data and said character image data read from said selected one of said first and second memories, so as to generate a drive signal;
and
a driver for controlling power conduction through said heating elements in accordance with said drive signal, so as to record dots in said pixels.

6 more elements

Dependencies are inferred from the claim text.

Thermal printing method and thermal printer

Life of this patent

Thermal printing method and thermal printer

Life of this patent

Abstract

Claims17