41results about How to "Density unevenness" patented technology

A printing apparatus and a printing method are provided which, even if a print position misalignment occurs between a plurality of print scans during a multipass printing, can minimize density variations in a unit area reliably and stably, thus producing an image without density unevenness. For this purpose, multi-grayscale-level image data is converted into a plurality of dot arrangement patterns that determine individual subpixels either to be printed or not to be printed with a dot. Then, these dot arrangement patterns are printed overlappingly on a print medium in different print scans of the print head. At this time, the plurality of dot arrangement patterns are so arranged that, if these dot arrangement patterns are shifted from one another, a change in the dot-overlapping area ratio will be smaller than when the dots are arranged separately so that they do not overlap one another.

An image is output, the image having high quality in which density unevenness due to an end-deviation is excellently reduced in all colors in forming an image with use of a bidirectional inkjet printing head provided with ejection port arrays of a plurality of colors for small droplets of ink. Thereby, distributions of print permission rates of mask patterns to be used in performing a multi-pass printing are made different from each other in accordance with a distance between the two ejection port arrays for the same kind of ink. Thus, the degree of the end-deviation depending on the distance between the two ejection port arrays can be suppressed for every ejection port array.

The present invention presents a stencil mask in which various surface patterns can be formed, and in which deformation is suppressed when charged particles are introduced. A stencil mask of the present invention is provided with a semiconductor stack. A first penetrating hole corresponding to an ion introducing area is formed in a first semiconductor layer of the semiconductor stack, and second penetrating holes are formed in a second semiconductor layer, these second penetrating holes having a width greater than the width of the first penetrating hole. The first penetrating hole and the second penetrating holes communicate and pass through the semiconductor stack. Beam members extending between adjacent second penetrating holes connect portions of the first semiconductor layer separated by the first penetrating hole.

After a first scan in a forward direction, conveying corresponding to one nozzle block is performed, and then in a second scan in a backward direction, printing of a “printing area 1,” which is a unit area, is completed. Then after completion of printing of the unit area, conveying corresponding to 14 nozzle blocks is performed. Then by reciprocal third and fourth scans, printing of a “printing area 2” is completed in a likewise manner. Subsequently, two scans in a reciprocal manner are performed in a likewise manner to perform printing of each unit area. In any unit area, printing time intervals between scans are such that, at a same position in a scan direction, the time interval is the same. Consequently, differences in density between unit areas that are adjacent in a conveying direction of a printing medium, that is, between-band unevenness becomes more difficult to recognize.

An optical scanning apparatus in which streaks in an image or unevenness in density of an image caused by influences of dusts, scratches and toner etc on the surface of a reflecting member are unlikely to occur and excellent images can be always obtained and an image forming apparatus equipped with such an optical scanning apparatus are to be achieved. The apparatus comprises a first optical system for guiding a light beam emitted from light source unit to deflecting unit, the deflecting unit for reflecting and deflecting the light beam from the first optical system, a second optical system for guiding the light beam reflected and deflected by the deflecting unit onto a surface to be scanned through reflecting unit including n (n is an integer equal to or larger than 1) reflecting members. The apparatus satisfies the following conditions for the F-number Fnomain (mm) with respect to a main scanning cross section of an exit side of the second optical system and the smallest beam area Smin (mm2) among beam areas on reflecting surfaces of the n reflecting members on which a light beam is reflected during traveling on the optical axis of the second optical system: 70<Fnomain, and (0.004 / Smin)×n<0.03.

A develop roller includes a magnet roller, and a develop sleeve containing the magnet roller and comprising a plurality of depressions in an elliptic shape regularly arranged with an interval in a longitudinal direction on a surface onto which developer is attracted by a magnetic force of the magnet roller, wherein the depressions are arranged such that a longitudinal direction of the depressions is intersected with the longitudinal direction of the develop sleeve, and a downstream side of the depressions are formed to be deeper than an upstream side in a rotary direction of the develop sleeve.

When an image processing apparatus of one aspect of this invention corrects input image data using correction values (misregistration correction amounts Δy), it determines whether or not image data to be corrected using amounts Δy includes a specific pattern which may cause density unevenness in an image to be formed. When the image processing apparatus determines that the image data includes the specific pattern, it modifies amounts Δy corresponding to pixels including the specific pattern of the amounts Δy using any of a plurality of different predetermined modulation amounts (modification values). Furthermore, the image processing apparatus corrects the image data for respective pixels using either the amounts Δy before modification, or the modified amounts Δy when the modification is done.