Abstract: A method of producing a water-absorbent resin of the present invention reduces amounts of a residual cross-linking agent and a residual surfactant, achieves high productivity, and improves physical properties of the resultant water-absorbent, such as absorption capacity, extractable polymer content, powder friction, and gel crushability. The method includes the steps of: polymerizing an aqueous monomer solution containing as a major component an acrylic acid monomer in the presence of a cross-linking agent; and drying the resultant polymer by heating, in which the cross-linking agent is a multifunctional (meth)acrylate cross-linking agent having polyethylene glycol structural units including a total of 6 to 200 ethylene oxide repeating units, and the aqueous monomer solution includes a mono(meth)acrylate compound having polyethylene glycol structural units in an amount of 0.1 to 30% by weight relative to an amount of the multifunctional (meth)acrylate cross-linking agent.

Abstract: In a multipass printing system, a quality image is printed even when the number of passes is reduced to increase a printing speed. For this purpose, in a multipass printing system which repetitively alternates a printing scan, which causes the print head to eject ink from the nozzles as it moves in the main scan direction, and a feeding operation, which feeds a print medium in a sub scan direction, the feed distance of the print medium is set according to a density of an image being printed on the print medium.

Abstract: A printing apparatus divides printing elements of a printhead into blocks, time-divisionally drives the printing elements, and prints a halftone image on a printing medium in accordance with a result obtained by performing digital-halftoning for input multi-valued image data in each matrix of a predetermined size. The apparatus includes a scanner for reciprocally scanning the printhead, a conveyor for conveying the printing medium in a direction different from a scanning direction of the printhead, and a controller for printing a halftone image in each matrix. An arrayed direction of the printing elements is the convey direction of the conveyor. The controller sets a size of the block to be equal to or an integral multiple of a size of the matrix in the convey direction. The digital-halftoning increases the number of dots from a center of the matrix as a density expressed by the multi-valued image data increases.

Abstract: A spliced ink-jet head including head chips, each of which is capable of discharging inks of two or more colors, and which are spliced in a staggered manner which restrains the occurrence of splice streaks, white streaks caused by deflection at ends or uneven colors attributable to different landing orders of ink droplets in spliced portions of different colors when one-pass recording is carried out. The head chips is arranged such that, in a relationship between two adjoining head chips, at least one discharge port of one head chip and one discharge port of the other head chip for the same color tone ink in end portions overlap on a line in a recording material feeding direction, while discharge ports for different color tone inks do not overlap.

Abstract: An inkjet printing apparatus which performs time-divisional driving poses the following problem for at least some gray levels when halftoning control by the unit matrix is performed. More specifically, the shape of a dot cluster in each unit matrix periodically changes due to the mismatch between the unit matrix size and the unit section size of time-divisional driving. For this reason, periodical density unevenness is generated and appears as degradation of the image quality. In order to prevent degradation of the image quality, according to this invention, image data is shifted in accordance with the unit section of time-divisional driving, or the discharge timing of ink from a printhead is shifted.

Abstract: In an inkjet printing apparatus which generates satellites droplets, problems in an image attributable to the satellites are mitigated as far as possible. For this purpose, each parameter is adjusted to satisfy a relationship such that the distance between positions of placement of a main droplet and a satellite substantially agrees with an integral multiple of the width of an index pattern. As a result, a satellite is likely to be placed in a position overlapping a dot formed by a main droplet printed in the same area of a pixel located in the vicinity of the satellite, which prevents satellites from placement blank positions where no dot should be printed. Thus, the influence of satellites is mitigated, and problems in an image attributable to satellite are reduced.

Abstract: A method of producing a water-absorbent resin of the present invention reduces amounts of a residual cross-linking agent and a residual surfactant, achieves high productivity, and improves physical properties of the resultant water-absorbent, such as absorption capacity, extractable polymer content, powder friction, and gel crushability. The method includes the steps of: polymerizing an aqueous monomer solution containing as a major component an acrylic acid monomer in the presence of a cross-linking agent; and drying the resultant polymer by heating, in which the cross-linking agent is a multifunctional (meth)acrylate cross-linking agent having polyethylene glycol structural units including a total of 6 to 200 ethylene oxide repeating units, and the aqueous monomer solution includes a mono(meth)acrylate compound having polyethylene glycol structural units in an amount of 0.1 to 30% by weight relative to an amount of the multifunctional (meth)acrylate cross-linking agent.

Abstract: In an inkjet printing apparatus which generates satellites droplets, problems in an image attributable to the satellites are mitigated as far as possible. For this purpose, each parameter is adjusted to satisfy a relationship such that the distance between positions of placement of a main droplet and a satellite substantially agrees with an integral multiple of the width of an index pattern. As a result, a satellite is likely to be placed in a position overlapping a dot formed by a main droplet printed in the same area of a pixel located in the vicinity of the satellite, which prevents satellites from placement blank positions where no dot should be printed. Thus, the influence of satellites is mitigated, and problems in an image attributable to satellite are reduced.

Abstract: An inkjet printing apparatus which performs time-divisional driving poses the following problem when halftoning control by the unit matrix is performed for at least some gray levels. More specifically, the shape of a dot cluster in each unit matrix periodically changes owing to the mismatch between the unit matrix size and the unit section size of time-divisional driving. The periodical change stands out as periodical density unevenness to the eye, degrading the image quality. In order to solve this problem, according to this invention, the unit matrix size and the unit section size of time-divisional driving are determined so that unit matrices have the same shape. More specifically, the unit section size of time-divisional driving and the unit matrix size in the nozzle array direction are set to (unit section size of time-divisional driving)×n=(unit matrix size in nozzle array direction) (n is a natural number).

Abstract: An inkjet printing apparatus which performs time-divisional driving poses the following problem for at least some gray levels when halftoning control by the unit matrix is performed. More specifically, the shape of a dot cluster in each unit matrix periodically changes due to the mismatch between the unit matrix size and the unit section size of time-divisional driving. For this reason, periodical density unevenness is generated and appears as degradation of the image quality. In order to prevent degradation of the image quality, according to this invention, image data is shifted in accordance with the unit section of time-divisional driving, or the discharge timing of ink from a printhead is shifted.

Abstract: In a multipass printing system, this invention prints a quality image even when the number of passes is reduced to increase a printing speed. For this purpose, in a multipass printing system which repetitively alternates a printing scan, which causes the print head to eject ink from the nozzles as it moves in the main scan direction, and a feeding operation, which feeds a print medium in a sub-scan direction, this invention sets the feed distance of the print medium according to a density of an image being printed on the print medium.

Abstract: A spliced ink-jet head including head chips, each of which is capable of discharging inks of two or more colors, and which are spliced in a staggered manner which restrains the occurrence of splice streaks, white streaks caused by deflection at ends or uneven colors attributable to different landing orders of ink droplets in spliced portions of different colors when one-pass recording is carried out. The head chips is arranged such that, in a relationship between two adjoining head chips, at least one discharge port of one head chip and one discharge port of the other head chip for the same color tone ink in end portions overlap on a line in a recording material feeding direction, while discharge ports for different color tone inks do not overlap.

Abstract: The present invention provides: a water-absorbing composition such that portions containing the water-absorbing composition in a high concentration exhibit excessive-liquid permeation buffering effects in absorbent articles comprising the water-absorbing composition and hydrophilic fibers; and a use of this water-absorbing composition. The water-absorbing composition comprises a water-absorbent resin and an excessive-liquid permeation buffer, wherein the water-absorbent resin is a product by a process including the step of further crosslinking the surface vicinity of a crosslinked polymer, and this water-absorbing composition is characterized by having a liquid permeation buffering index of not less than 0.