Gravure engraving system and method including engraving overlapping cells

A method of engraving a plurality of cells on a surface of a gravure cylinder, comprising:

• a first step of superposing a density signal on a carry signal to generate an engraving signal;
• a second step of causing a stylus to reciprocatively vibrate in accordance with said engraving signal to engrave cells to the gravure cylinder rotating in a main scanning direction;
• and
• a third step of moving said stylus in a sub-scanning direction perpendicular to the main scanning direction every time cells for one line in the main scanning direction have been engraved to said gravure cylinder;
• said third step controlling a moved amount of said stylus so that a first pitch and a second pitch alternately appear in every other line in a plurality of cell lines formed along said main scanning direction, thereby to partially overlap those two cells adjacent in the sub-scanning direction which define said first pitch and whose total width in the sub-scanning direction is larger than a prescribed threshold.

A gravure engraving system for engraving a plurality of cells on a surface of a gravure cylinder to manufacture an intaglio for gravure printing, the gravure engraving system comprising:

• rotating driver for rotating said gravure cylinder in a main scanning direction;
• carrier signal generator for generating a carrier signal in the form of a sine wave having a prescribed frequency and a prescribed amplitude;
• density signal generator for generating a density signal having its level varying in accordance with a tone of provided image data;
• engraving signal generator for generating an engraving signal by superposing said density signal on said carrier signal;
• stylus vibrating in accordance with said engraving signal to engrave cells in the gravure cylinder rotating in the main scanning direction;
• stylus driver for moving said stylus in a sub-scanning direction perpendicular to the main scanning direction;
• and
• a controller for controlling movement of said stylus by said stylus driver so that a first pitch and a second pitch alternately appear in every other line of a plurality of cell lines formed along said main scanning direction;
• wherein two cells adjacent in the sub-scanning direction partially overlap each other to define said first pitch and whose total width in the sub-scanning direction is larger than a prescribed threshold.