Dainippon Screen Mfg. Co., Ltd.

Screen Holdings Co., Ltd.

Masayuki Nakano

Hiroshi Asai

Yasuhiro Takemoto

Kazushi Moriwaki

Koichi Isono

Tetsuya Ishida

Satoshi Yasuda

Yoshiyuki Nishigaito

A printing apparatus comprises: a transport mechanism that transports a recording medium; a first line head group including a first line head in number of N that ejects first ink; a second line head group including a second line head in number of M that ejects second ink; and a controller, where M is a natural number larger than N. The line heads form images along lines extending in a width direction along a surface of the recording medium by ejecting ink droplets from a plurality of nozzles aligned in the width direction. In a first printing step, the controller makes each of the first line head in number of N perform printing process on every N-th line, while making each of the second line heads in number of M perform the printing process on every M-th line.

Inkjet printing apparatus

A printed material has a transparent base member, a first image layer formed on the base member, an intermediate layer formed on the first image layer, and a second image layer formed on the intermediate layer. The intermediate layer has a lower white background layer positioned above the first image layer, a light blocking layer positioned above the lower white background layer, and an upper white background layer positioned above the light blocking layer. In the printed material, a thickness of the light blocking layer is uneven in conformity with undulation of the first image layer, and therefore a surface of the intermediate layer which is in contact with the second image layer is flat. With this structure, it is possible to prevent or suppress the undulation of the first image layer from appearing in the second image layer.

Printed material, method of producing printed material, and printer

A printed material () has a transparent base member (), a first image layer () formed on the base member, an intermediate layer () formed on the first image layer, and a second image layer () formed on the intermediate layer. The intermediate layer has a lower white background layer () positioned above the first image layer, a light blocking layer () positioned above the lower white background layer, and an upper white background layer () positioned above the light blocking layer. In the printed material, a thickness of the light blocking layer is uneven in conformity with undulation of the first image layer, and therefore a surface of the intermediate layer which is in contact with the second image layer is flat. With this structure, it is possible to prevent or suppress the undulation of the first image layer from appearing in the second image layer.

In a head () of an inkjet printer, a plurality of outlet rows are arranged in a scanning direction, the plurality of outlet rows each having a plurality of outlets arranged in a direction intersecting the scanning direction. The plurality of outlets are each capable of forming dots of a plurality of sizes on printing paper upon receiving different driving signals from an ejection control part (). In the inkjet printer, under control of the ejection control part (), some of the outlet rows form dots of only one size out of the plurality of sizes, and the other outlet rows form dots of only another size. In this way, causing the plurality of outlets in each outlet row to form dots of only one size makes it possible to reduce the occurrence of satellite droplets or the like and improve print quality.

Inkjet printer and printing method

To generate a threshold matrix which is compared with an original image in creating a halftone dot image for each color component, in a matrix area for one color component, dot centers are arranged almost uniformly in a random fashion at a predetermined density and in a matrix area for another color component, dot centers are arranged almost uniformly in a random fashion at a density about 0.7 times the predetermined density. Then, threshold values are set so that dots should grow around the dot centers in accordance with an increase in gray level of the original image, to generate the threshold matrix for each color component. In creating the halftone dot images by using these threshold matrixes, characteristics of spatial frequency of the halftone dot images of these color components can be represented in a frequency space as areas (K,C) in a shape of concentric rings. As a result, it is possible to create a multicolor halftone dot image with less graininess, with no portions approximate to each other in the characteristics of spatial frequency of these halftone dot images.

Method of generating threshold matrix for creating halftone dot image and method and apparatus for creating halftone dot image and recording medium

In a threshold matrix generation partimplemented by a computer, a tint image in a specified gray level is generated from temporary lighting order set in a matrix area, and a smoothing operation is performed on the tint image, to generate a grayscale evaluation image. The lighting order is modified by changing ordinal numbers in the lighting order of respective positions included in specified areas in the matrix area which correspond to areas around boundaries of halftone dot areas in the tint image on the basis of values of corresponding pixels in the evaluation image. With this operation, when the smoothing operation is performed on a tint image in the specified gray level generated in accordance with a modified lighting order, a variation among values of pixels included in the specified areas becomes smaller than a variation among values of pixels included in the specified areas in a case where the smoothing operation is performed on the tint image in the specified gray level generated in accordance with an unmodified lighting order. Then, threshold values are determined in the matrix area with reflecting the modified lighting order, to generate the threshold matrix which is possible to suppress graininess in a generated halftone dot image.

Threshold matrix generation method, threshold matrix generation apparatus, and recording medium

Halftone dots are formed on the basis of three sets of screen pattern data assigned to the to a same combined area, in which a plurality of halftone dots are to be formed. The three sets of screen pattern data have different threshold values assigned to respective pixels in the combined area, and are stored in SPM's (101-116). Eight SPM's (Screen Pattern memory units) store a first set of the screen pattern data, six SPM's store a second one, end two SPM's store a third one. One of the sixteen SPM's is randomly selected with respect to each pixel, whereby one of the threshold values (D.sub.s) stored in the selected SPM is compared with an iamge signal (V.sub.1). A dot signal indicating whether or not each pixel is solid is produced on the basis of the comparison. Accordingly, a grid-like pattern of halftone dots to be seen in a highlight area or a shadow area is prevented.

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Kyoto, Japan

Masayuki Nakano