Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1997-06-30
2001-09-25
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S043000, C347S019000
Reexamination Certificate
active
06293640
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing apparatus and a printing method for printing images while performing scanning with a printer head in a main scanning direction with respect to a printing medium.
2. Description of the Related Art
As a known conventional example of a printing apparatus of this type, there exists an ink jet printer, in which a number of nozzles are arranged on the printer head. In this ink jet printer, when ejecting ink by driving aelectrostrictive elements provided behind the nozzles in the printer head, a current of approximately 50 mA flows momentarily in a drive circuit for driving one electrostrictive element.
To cause ink to be ejected simultaneously from a number of nozzles by using such drive circuits, it has been necessary to momentarily supply an enormous consumption current. Thus, there has conventionally been proposed an arrangement in which, to reduce the momentarily required consumption current by supplying current on a time-division basis to each drive circuit in order that a number of electrostrictive elements may be driven without using a power source of a large capacity.
However, when causing ink to be ejected from the nozzles by driving the electrostrictive elements on a time division basis while continuously performing scanning with the printer head, a positional deviation occurs in printing in the ink ejected from the nozzles due to a difference in drive timing between the electrostrictive elements, resulting in a deterioration in image quality. This is particularly conspicuous in the case of the printing of an image having a longitudinal line component.
SUMMARY OF THE INVENTION
In view of the above problem, it is an object of the present invention to provide a printing apparatus and a printing method which can prevent a deterioration in print quality when printing on a time-division basis while performing scanning continuously with the printer head.
To achieve the above object, there is provided, in accordance with claim
1
of the present invention, a printing apparatus of the type in which scanning is performed with a printer head in a main scanning direction with respect to a printing material to thereby print an image, wherein N recording elements are arranged on the printer head in a sub-scanning direction at intervals of K dots such that K/N is an irreducible fraction, and wherein there is provided a grouping means which, when printing is effected by driving the above-mentioned recording elements while effecting an interlaced scanning with the above-mentioned printer head for each predetermined dot interval, divides the above-mentioned recording elements into groups each consisting of recording elements driven with the same timing and determines the drive sequence for these groups such that the printing position on the above-mentioned recording material for a given recording element is, with respect to the main scanning direction, the same as or adjacent to the printing positions for those recording elements which are adjacent to that recording element with respect to the sub-scanning direction.
It is desirable that the above-mentioned printer head be equipped with a plurality of recording heads, each recording head being equipped with the above-mentioned recording elements of cyan, magenta and yellow, or the above-mentioned recording elements of cyan, magenta, yellow and black. Further, it is desirable for the above-mentioned grouping means to effect the above-mentioned division into groups and determine the above-mentioned drive sequence such that the case is included in which the printing position for the above-mentioned given recording element is, with respect to the main scanning direction, close to the printing position for those recording elements adjacent thereto in the sub-scanning direction. Further, the present invention is applicable to a two liquid mixing type ink jet printer in which ink and diluent are mixed with each other before being ejected from a nozzle, wherein it is desirable that the above-mentioned recording elements be equipped with ejection means for ejecting the above-mentioned mixture ink from the above-mentioned nozzles and determination means for providing a determined amount of the above-mentioned ink. Further, it is desirable that the present invention be applicable to a head scanning type on-demand printing apparatus in which the above-mentioned printer head moves in the main scanning direction with respect to the above-mentioned recording material. Further, it is desirable that the above-mentioned recording elements be driven during the forward and backward movements of the above-mentioned printer head.
In accordance with claim
7
of the present invention, there is provided a printing method of the type in which scanning is performed with a printer head in a main scanning direction with respect to a printing material to thereby print an image, wherein N recording elements are arranged on the printer head in a sub-scanning direction at intervals of K dots such that K/N is an irreducible fraction, and wherein when the above-mentioned recording elements are driven while effecting an interlaced scanning with the above-mentioned printer head for each predetermined dot interval, the above-mentioned recording elements are divided into groups each consisting of recording elements driven with the same timing and the drive sequence for these groups is determined such that the printing position on the above-mentioned recording for a given recording element is, with respect to the main scanning direction, the same as or adjacent to the printing positions for those recording elements which are adjacent to that recording element with respect to the sub-scanning direction.
REFERENCES:
patent: 4540996 (1985-09-01), Saito
Barlow John
Sonnenschein Nath & Rosenthal
Sony Corporation
Stewart Jr. Charles W.
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