摘要:
An ink-jet printing apparatus and an ink-jet printing method allow the printing of an image with high quality without causing a change in ink color formed on the printing medium while keeping the printing conditions constant regardless of changing of the number of nozzles to be printed and the amount of transferring of the printing medium. This printing is performed, for example, by restricting use of the number of nozzles, which belong to a nozzle row located on an upstream side in the sub-scan direction, before changing the amount of transferring of the printing medium; and restricting use of the number of nozzles, which belong to the nozzle rows located on a downstream side in the sub-scan direction, after changing the amount of transferring of the printing medium.
摘要:
In an ink jet print head used in a serial type ink jet printing apparatus according the present invention, a portion of the nozzle column is given a wider nozzle-to-nozzle interval than those of other portions of the nozzle column so that the width in the line feed direction of each image area printed in a single printing scan by the ink jet print head is longer than a distance that a print medium is moved by one line feed. In this serial print head, the width of each image area printed by a single printing scan can be made a predetermined amount longer than the line feed distance at all times. As a result, the adjoining image areas printed by separate printing scans overlap each other at their boundary portions by a predetermined amount.
摘要:
A print apparatus that, without significantly reducing an overall printing speed, allows a reduction in uneven densities due to the discharge time difference between black ink and color inks, which occur particularly at both ends in a scanning range and which are caused by the printing by bidirectional scanning of print heads, and enables high image-quality printing to be realized. In this print apparatus, one band is divided into plural areas in a main scanning direction, the dot numbers of black ink and color ink imparted to respective areas are counted. If there are any areas where the dot numbers of both black and color exceed respective threshold values, the area number is counted, and if the number exceeds a predetermined number, the print mode is switched from bidirectional printing to a unidirectional one, upon determining that there is a high probability of occurrence of the above-described uneven densities.
摘要:
There is provided a printing registration method for stably performing printing registration in bi-directional scanning by a print head in a printing apparatus or printing registration between a plurality of print heads with high accuracy. In complementary printing by the bi-directional scanning by the head, a plurality of patterns are printed while printing starting timings are shifted by predetermined quantities with respect to reference dots (dots formed by forward scanning). In the pattern, an area factor defined by the dots formed by the printing is varied according to the shifting. The plurality of patterns are optically read as an average density. The timing corresponding to a point where the read average density is highest can be determined as a printing registration condition. Furthermore, an optical sensor used for the reading is located at a position where an S/N ratio is stable with respect to fluctuations in distance from the object to be read, thus achieving stable reading.
摘要:
In complementarily printing by bi-directional scannings of a head or by a plurality of print heads, first patterns and second patterns including reference dots for example, dots formed by a forward scan of the bi-directional scannings or by one of the plurality of print heads and dots each having the different direction of shifting of relative printing positions to the reference dots are printed in corresponding to the plurality of shifting amounts. These first and second patterns have the similar characteristics of a change in density. The difference is only that their characteristics in density change are inverted according to the direction of shifting. The intersection point of these two characteristics in density change is obtained as a position for adjustment where dot-formed positions match. This makes it easy to perform printing registration in a printing apparatus in the case of printing by a forward and reverse scan of a printing head or in the case of printing by means of a plurality of printing heads. In this case, operations by a user etc. are also unnecessary and are easily performed.
摘要:
The present invention reduces a difference in speed between a main drop section and a tailing section of a ejected ink droplet by heating a front heater and a rear heater provided for one nozzle with a predetermined time lag and thus, the ink dot formed from the main drop section and the tailing section on a printing medium can be more approximate to a circle. Thereby, it is possible to prevent print quality from being degraded by the tailing section separated from the main drop section of the ink droplet ejected from an ink jet printing apparatus of serial type.
摘要:
In a complimentary printing by bi-directional scanning of a head or by a plurality of heads, a plurality of patterns in which a print start timing is shifted by a predetermined amount are printed with respect to a reference dot, e.g. formed by the forward scan of the bi-directional scanning or by one of the plurality heads. In these patterns, an area factor by the dots formed by printing of the patterns is designed to be varied depending upon shifting amount. An average density is read from each of the plurality of patterns, optically. The timing at which the maximum one among average densities read from the patterns is obtained, can be set as the printing registration condition. Further, a processing including a coarse adjustment to a fine adjustment is performed in a series of algorithm. By these processings, printing registration between a forward and a reverse scan of a print head or printing registration between a plurality of print heads in a printing apparatus can be performed simply and with high accuracy, without operating by a user.
摘要:
In an ink jet printing apparatus using many types of inks to execute bidirectional printing, if ejection opening rows for yellow, magenta, and cyan inks are symmetrically arranged, ejection opening rows for a black ink are arranged adjacent to the most inside ejection opening rows for the yellow ink. Thus, a difference in color between forward scanning and backward scanning is determined by a difference in coloring between the black ink and the yellow ink. In this case, a possible color drift attributed to bidirectional printing can be suppressed by selecting the inks so that the difference in coloring between the black ink and the yellow ink is smaller than that between the black ink and the other color inks.
摘要:
In an image processing method, on the basis of input image data with respect to a target pixel, independent multi-level data (g0, g1) corresponding to respective plural species of dots which are different in at least one of a density and a diameter are generated, and then data (O0, O1) relating to an amount of generation of the dots with respect to the target pixel are generated on the basis of a relationship between the generated independent multi-level data (g0, g1) corresponding to the plural species of dots. The image processing method is effective in performing design having a high degree of flexibility in proper use of a relatively high power dot (high density dot or large dot) and a relatively low power dot (low density dot or small dot) and can realize obviation or alleviation of an occurrence of granulation or an apparent frame caused due to the relatively high power dot.
摘要:
In an ink jet printing apparatus using many types of inks to execute bidirectional printing, if ejection opening rows for yellow, magenta, and cyan inks are symmetrically arranged, ejection opening rows for a black ink are arranged adjacent to the most inside ejection opening rows for the yellow ink. Thus, a difference in color between forward scanning and backward scanning is determined by a difference in coloring between the black ink and the yellow ink. In this case, a possible color drift attributed to bidirectional printing can be suppressed by selecting the inks so that the difference in coloring between the black ink and the yellow ink is smaller than that between the black ink and the other color inks.