Patent ID: 6290317
Filing Date: 2001-09-18
Classification: B41J,H04N

Abstract:
A method of forming a half-tone image by applying a pulse voltage to a print head of a printing device, the pulse voltage being representative of image data, the method comprising the steps of:receiving image data;converting each unit of image data into one pulse voltage for driving the print head of the printing device, wherein each pulse voltage is one of a plurality of pulse voltages of a pulse voltage set, and each pulse voltage represents a tone gradation; andapplying each pulse voltage to the print head to discharge an ink drop representative of a tone gradation for each corresponding image data unit,wherein a first pulse voltage of the pulse voltage set has a first waveform including a first rising interval, a first falling interval, and a first pulse amplitude at a maximum voltage level,wherein a second pulse voltage of the pulse voltage set has a second waveform including a second rising interval, a second falling interval, and a second pulse amplitude at a maximum voltage level,wherein the second pulse voltage corresponds to a gradation level greater than a gradation level of the first pulse voltage to produce a printed ink dot greater in diameter than a printed ink dot diameter from the first pulse voltage, andwherein the first rising interval is less than the second rising interval, the first falling interval is less than the second falling interval, and the first pulse amplitude and the second pulse amplitude are equal.