Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2000-03-07
2002-07-02
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S106000
Reexamination Certificate
active
06412897
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an image printing method and device for printing a print image on a printing object by using an ink.
2. Prior Art
Conventionally, the method of printing a print image by using an ink includes a dot impact method and a thermal method which use a ribbon containing ink or the like, as well as an ink jet printing method in which ink droplets are ejected. In the ink jet printing method, for instance, printing is carried out by blowing (ejecting) ink droplets corresponding to dots of a desired print image onto a printing object from nozzles of an ink jet head (print head). When the print image is a color image, inks of three primary colors of C (cyan), M (magenta), and Y (yellow), or four basic colors of the three primary colors plus K (black) are ejected to corresponding dots of a print image according to a desired print color of the print image, to thereby carry out color printing.
The image printing method of the above-described kind which uses inks, particularly, the ink jet printing method, suffers from a problem of degradation of quality of a printed image due to mixing of adjacent printed dots through blotting of ink on the printing object or on the contrary due to increased space between printed dots caused by limited spreading of ink on the printing object. That is, even if ink is ejected to the center of each print dot, the size and density of the printed dot varies with the degree of permeation of ink into the printing object (hereinafter referred to as “penetration rate”), which can prevent a print image having a desired quality from being obtained even if printing control conditions, such as a print density (reciprocal of a distance between centers of adjacent print dots), are set to predetermined suitable conditions.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an image printing method and device which is capable of maintaining quality of a print image printed on a printing object by using ink even when the penetration rate of ink into the printing object has changed.
To attain the above object, according to a first aspect of the invention, there is provided a method of printing a print image on a printing object by using ink, comprising the steps of:
detecting factors causing a change in a penetration rate of at least one kind of ink into the printing object;
setting printing control conditions in dependence on results of detection of the factors causing the change in the penetration rate; and
printing the print image on the printing object by using the at least one kind of ink based on print image data representative of the print image and the printing control conditions.
To attain the above object, according to a second aspect of the invention, there is provided an image printing device comprising:
a penetration rate-changing factor-detecting section for detecting factors causing a change in a penetration rate of at least one kind of ink into a printing object;
a printing control condition-setting section for setting printing control conditions in dependence on results of detection of the factors causing the change in the penetration rate; and
an image printing section for printing the print image on the printing object by using the at least one kind of ink based on print image data representative of the print image and the printing control conditions.
According to the image printing method and device, factors causing a change in a penetration rate of at least one kind of ink into a printing object are detected, and printing control conditions are set in dependence on results of detection of the factors causing the change in the penetration rate. The print image is printed on the printing object by using the at least one kind of ink based on print image data representative of the print image and the printing control conditions. That is, by detecting the factors causing the change in the penetration rate of ink, a change of the penetration can be expected, and the printing control conditions are set according to the results of detection of the factors causing the change. Therefore, it is possible to set suitable printing control conditions according to the change in the penetration rate, and the print image is printed based on the printing control conditions thus set. Therefore, even if the penetration rate of the ink into the printing object has changed, it is possible to maintain the quality of a print image printed on the printing object by using the ink.
Preferably, the printing control conditions include a print density which is inversely proportional to a distance between centers of adjacent print dots of the print image.
As described hereinbefore, if the penetration rate of the ink into the printing object has changed, the quality of the print image can be degraded due to mixing of adjacent printed dots or on the contrary due to increased space between printed dots caused by limited spreading of ink on the printing object. According to the preferred embodiment of each aspect of the invention, the printing control conditions based on which printing is controlled include a print density which is inversely proportional to a distance between centers of adjacent print dots of the print image, and hence it is possible to set the print density according to the change in the penetration rate of ink into the printing object, whereby even if the penetration rate of ink into the printing object has changed, the quality of a print image printed by using the ink can be maintained.
Preferably, the step of printing the print image includes printing the print image while causing relative movement of at least one of a print head that ejects droplets of the ink and the printing object relative to each other, and the printing control conditions include a speed of the relative movement.
Preferably, the image printing section includes a print head that ejects droplets of the ink, and a relative movement section for causing relative movement of at least one of the print head and the printing object relative to each other, and the printing control conditions include a speed of the relative movement.
Generally, if a time period (drying time) which ink of print dots takes to become dry changes, the penetration rate changes at which the ink penetrates into a printing object before the ink becomes dry. If the penetration rate changes, the size of the print dot also changes. Therefore, when the penetration rate of ink into a printing object has changed, if a time period or a time interval from a printing operation for printing an arbitrary print dot to a printing operation for printing a print dot adjacent thereto is uniformly set to a predetermined value, that is, if the printing speed is uniformly set to a predetermined value, print dots adjacent to each other in the direction of printing (direction of relative movement) can be mixed with each other, thereby degrading the quality of a print image. Inversely, if unnecessarily long drying time is secured, the printing speed is unnecessarily lowered.
According to the preferred embodiment of each aspect of the invention, the print image is printed by moving at least one of the print head for ejecting droplets of ink onto the printing object and the printing object relative to each other, and the printing control conditions thereof include the speed of the relative movement. Therefore, it is possible to set the speed of the relative movement as a printing control condition according to the change in the penetration rate, thereby making it possible to change the printing speed. As a result, it is possible to set a printing speed at which a minimum drying time may be secured for maintaining the quality of the print image. Therefore, even if the penetration rate of ink into the tape (printing object) has changed, the quality of a print image printed by using the ink can be maintained. Further, since the print image can be printed at a suitable printing speed in manner varying with the change in the penetration rate, it is possible to preven
Hayama Hitoshi
Konishi Yoshiharu
Barlow John
Dudding Alfred
Hogan & Hartson L.L.P.
Seiko Epson Corporation
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