Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-03-22
2004-01-20
Nguyen, Thinh (Department: 2861)
Incremental printing of symbolic information
Ink jet
Controller
C347S043000
Reexamination Certificate
active
06679575
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a medium storing a print density correction program which corrects the print density on the basis of variations in ink density, an apparatus and method for the correction of print density, a medium which stores a print control program, and an apparatus and method for print control.
2. Description of the Prior Art
In a conventional ink jet printer which makes printing by ejecting ink onto a recording medium such as paper, the amount of ink is kept constant when printing is made at a predetermined print density irrespective of a residual amount of ink.
In the above conventional ink jet printer, particularly when using a pigment-based ink, the print density changes with time, depending on a residual amount of ink, with consequent variations in ink density. That is, the ink density is low in an upper layer within an ink cartridge filled with ink and becomes higher gradually toward a lower layer. In printing, ink is used successively from the lower layer of a high ink density. Therefore, as the amount of ink becomes small, the ink density becomes low and so does the print density gradually.
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of the above-mentioned problem and it is an object of the invention to provide a medium storing a print density correction program which corrects the print density on the basis of variations with time in ink density to permit printing at a constant print density, an apparatus and method for the correction of print density, a medium which stores a print control program, and an apparatus and method for print control.
In the medium which stores a print density correcting program according to the present invention, the program causes a computer to correct variations in print density based on variations in ink density and corresponding to changes with time in ink density in a printer which makes printing by ejecting ink onto a printing medium. In accordance with the print density correcting program the computer is allowed to execute an identification information acquiring function of acquiring identification information which permits the degree of variations in ink density to be identified directly or indirectly, as well as a print density correcting function comprising acquiring a correction coefficient for correcting variations in print density corresponding to changes with time in ink density and correcting the print density so as to eliminate the variations in print density in accordance with the acquired correction coefficient.
In the present invention thus constructed, the computer executes the identification information acquiring function, that is, acquires identification information which permits the degree of variations in ink density to be identified directly or indirectly in a printer, the printer ejecting ink onto a printing medium to effect printing, then the computer executes the print density correcting function, that is, acquires a correction coefficient for correcting the variations in print density corresponding to the changes with time in ink density in accordance with the identification information acquired, and thereafter corrects the print density so as to eliminate the variations in print density on the basis of the correction coefficient thus acquired.
Usually, when printing is performed on the basis of a predetermined print density, there is made control so that a predetermined amount of ink which can realize the said print density is ejected onto a printing medium. However, if there are variations in the density of the ink ejected, even if the ink is ejected in the predetermined amount onto the printing medium, there will occur variations in the actual print density which is expressed by the said amount of ink. In the present invention, when printing is performed, the print density is corrected while taking such variations in ink density into account so that the actual print density becomes a desired print density.
Therefore, according to the present invention it is possible to provide a medium storing a print density correcting program which corrects the print density on the basis of variations in ink density, thereby permitting printing to be carried out at a certain constant print density even with the lapse of time.
In executing the identification information acquiring function, that is, when acquiring identification information which permits the degree of variations in ink density to be identified, a state of ink may be acquired directly and used as the identification information, or there may be acquired identification information which can identify the degree of variations in ink density indirectly. In executing the identification information acquiring function, the timing for acquiring the same information is not specially limited. The identification information may be acquired when printing is started, or it may be acquired during printing. The print density correcting function may be carried out so as to correct the print density in accordance with the identification information thus acquired.
As to the identification information acquired by the identification information acquiring function, no special limitation is placed on whether it is to be acquired directly or indirectly insofar as it can identify the degree of variations in ink density as noted above.
As an example of identification information able to identify the degree of variations in ink density, there may be adopted a construction wherein information on the amount of ink used is acquired as the identification information in the identification information acquiring function and a correction coefficient based on a correlation between the information on the amount of ink used and information on changes in print density is acquired in the print density correcting function.
According to this construction, information on the amount of ink used is acquired as the identification information by the identification information acquiring function, so in the print density correcting function there is acquired a correction coefficient based on a correlation between the information on the amount of ink used and information on changes in print density. The information on the amount of ink used, which is acquired by the identification information acquiring function, may be one managed by a printer connected to an apparatus which implements the same function or may be one managed by a print controller which controls the printer. It may be changed as necessary. As to the amount of ink used, an actual amount of ink used may be measured and used as the information on the amount of ink used, or a residual amount of ink may be measured to determine the amount of ink used indirectly and the amount of ink thus determined may be used as the information on the amount of ink used, or the amount of ink used may be determined on the basis of the number of printed sheets and used as the information on the amount of ink used. Thus, a change maybe made as necessary. The degree of variations in ink density depends on changes with time after charging the ink into an ink cartridge or the like, so by utilizing the information on the amount of ink used it becomes possible to identify such changes with time, i.e., the degree of variations in ink density.
This permits the correction of the print density in accordance with the information on the amount of ink used.
As noted above, the degree of variations in ink density depends on changes with time after the ink has been charged into an ink cartridge or the like. As another example of identification information able to identify the degree of variations in ink density based on such changes with time in ink density, there may be adopted a construction wherein information on the manufacture of ink is acquired as the identification information in the identification information acquiring function, while in the print density correcting function there is acquired a correction coefficient based on a correlation between elapsed time after
Mattingly Stanger & Malur, P.C.
Nguyen Thinh
Seiko Epson Corporation
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