US 5,844,585 AGranted

Apparatus and method for printing high-quality color image at high speed

AssigneeSeiko Epson Corporation

InventorsNorihiko Kurashima, Kazumichi Shimada

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Abstract

A color ink jet printer having high throughput and a high-quality printing capability is disclosed. Nozzle arrays for spouting black ink, cyan ink, magenta ink, and yellow ink are placed on a print head. Each of the nozzle arrays has N nozzles arranged in a vertical scanning direction at intervals of k times the dot pitch of a print image. The nozzles are driven at intermittent timing during the horizontal scanning of the print head for forming dots at intervals of s times the dot pitch. At the termination of the horizontal scanning, vertical scanning is executed by a given distance. The vertical scanning distance L is set so as to satisfy the following expression: L=N/(s.multidot.D.multidot.k) wherein s is an arbitrary integer greater than one and less than N, and a submultiple of N, k is an arbitrary integer greater than one and less than N having prime relation with N/s, and D is the number of nozzles existing per unit distance in the vertical scanning direction.

Claims14

Dependent claims

An apparatus in which a print head thereof executes a horizontal scanning and a vertical scanning on a surface of a print medium for printing the surface of the print medium, the apparatus comprising:

a dot formation element array having N dot formation elements for forming dots of a single color, N being a finite, positive integer treater than one, said dot formation elements being arranged on a surface of the print head and facing the print medium at a constant pitch in the vertical scanning direction;
horizontal scanning drive means for executing the horizontal scanning of the print head;
head drive means for driving said dot formation element array during the horizontal scanning;
and
vertical scanning drive means for executing the vertical scanning of the print head by a predetermined distance L each time the horizontal scanning terminates;
wherein the following conditions are satisfied:
s is an arbitrary integer greater than one and less than N,
k is an arbitrary integer greater than one and less than N and which is not commensurable with N/s, and
L=N/(s.multidot.D.multidot.k);
wherein L is a vertical scanning pitch which is the predetermined distance of one vertical scanning, s is the number of scan repetitions which is the number of horizontal scanning repetitions required for printing a line continuous in a horizontal scanning direction, k is an element pitch which is a value representing a vertical distance between center points of contiguous ones of the dot formation elements, expressed as a multiple of a dot pitch of a print image, and D is an element density which is the number of the dot formation elements existing per unit of vertical distance in said dot formation element array.

7 more elements

A method of printing on a surface of a print medium with a print head having a dot formation element array including N dot formation elements for forming dots of a single color arranged at a constant pitch in a vertical scanning direction, where N is a finite, positive integer greater than one, the method comprising the steps of:

executing horizontal scanning of the print head;
driving said dot formation element array during the horizontal scanning;
executing vertical scanning of the print head by a predetermined distance L each time the horizontal scanning terminates;
selecting s which is an arbitrary integer greater than one and less than N;
selecting k which is an arbitrary integer treater than one and less than N and which is not commensurable with N/s;
and
selecting L which satisfies the following equation,
L=N/(s.multidot.D.multidot.k);
wherein L is a vertical scanning pitch which is the predetermined distance of one vertical scanning, s is the number of scan repetitions which is the number of horizontal scanning repetitions required for printing a line continuous in a horizontal scanning direction, k is an element pitch which is a value representing a vertical distance between center points of contiguous ones of the dot formation elements, expressed as a multiple of a dot pitch of a print image, and D is an element density which is the number of the dot formation elements existing per unit of vertical distance in said dot formation element array.

6 more elements

Dependencies are inferred from the claim text.