Riso Kagaku Corporation

Takashi Ebisawa

Mitsuaki Ishitoya

Ryo Terakado

Mamoru Saitou

Toshihide Maesaka

Yoshiyuki Okada

Yukio Yoshikawa

Bai Xuqiang

Hiroyuki Watanabe

A controller performs control to: print a test pattern on a print medium, the test pattern including: a head reference straight line extending in a main scanning direction and printed by a reference print head; and head adjustment straight lines extending in the main scanning direction and printed by each of non-reference print heads at timings corresponding to timing adjustment values; and in response to input of information specifying the head adjustment straight line with a smallest print misalignment amount in the sub-scanning direction with respect to the head reference straight line for each of the non-reference print heads, determine, for each of the non-reference print heads, the timing adjustment value corresponding to the head adjustment straight line specified by the input information as an adjustment value of an ink ejection timing in the non-reference print head in normal printing.

Inkjet printer with ejection adjustment function based on test pattern

There is provided a distance calculator configured to calculate an amount of displacement of an inkjet head in the main scanning direction, and an inter-pixel distance between neighboring pixels adjacent in the main scanning direction, based on read-in test pattern image data (test image data) read from an original subjected to printing based on test pattern image data printed by discharging from a plurality of nozzles, and an image processor configured to correct image data included in a received print job so as to increase, in accordance with the amount of displacement, the amount of ink to be discharged from nozzles corresponding to positive correction target pixels whose calculated inter-pixel distance exceeds an inter-pixel threshold value (a predetermined distance).

Inkjet printer correcting image data based on calculated inkjet head displacement and inter-pixel distances

The controller is configured to: drive a color ink ejection head and a functional ink ejection head to print test images on a sheet in a plurality of types of test patterns between which a positional relationship of a dot of a color ink and a dot of a functional ink to be formed on the sheet is varied; determine an overlapping degree of the dot of the color ink and the dot of the functional ink in the respective printed test images on a basis of a color attribute of the respective printed test images; and control the functional ink ejection head in printing on a basis of a control content corresponding to at least one test pattern selected of the plurality of types of the test patterns on a basis of the determined overlapping degrees.

Inkjet printer

An inkjet printer includes nozzle rows aligned along a printing direction along which printing on a print medium is executed, and a controller configured to control ejection of the ink droplets from the nozzle rows. The nozzle rows include a pair of an upstream nozzle row and a downstream nozzle row. The upstream nozzle row is positioned just upstream from the downstream nozzle row along the printing direction. The controller controls ejection of the ink droplets from the upstream nozzle row and the downstream nozzle row so that propulsive forces applied to ink droplets ejected from the downstream nozzle row are made larger, based on image data associated with the upstream nozzle row, than propulsive forces applied to ink droplets ejected from the upstream nozzle row. The inkjet printer can restrict degradation of print quality by landing the ink droplets ejected from the downstream nozzle at their target positions.

An image forming apparatus includes at least one inkjet head which is disposed above a feed path of a print medium and on which plural nozzles are aligned along a primary sweeping direction perpendicular to a feed direction of the print medium fed along the feed path. The image forming apparatus forms images by ejecting ink droplets from the nozzles. The image forming apparatus includes a controller that is operable to compensate ejection timings of ink droplets to be ejected from the nozzles onto the print medium based on ejection density of the ink droplets. The image forming apparatus can form good images that are not affected by ink dot displacements caused by feed airflow even when the ink dot displacements are affected by self-induced airflow.

Image forming apparatus

A specific gamut of colors extending a reproduction range of colors in a color space is set to make for any ink color belonging to the specific gamut a conversion from CMYK dot pattern data into numbers of ink drops to be discharged from an inkjet head, using as a lookup table an extended pattern table having a maximal drop number '7'. For ink colors belonging to a gamut of colors outside the specific gamut, a default pattern table having a maximal drop number '5' is used as a lookup table for the conversion from CMYK dot pattern data into ink drop numbers.

Printing method and printing processor for color images

Displacement information indicating a displacement amount of landing position in a main scanning direction of ink droplets discharged respectively from the nozzle of the head module of the same array of the line head of each color is acquired for each head module of the same array (steps S, S). Based on the displacement information and concentration information for each array, a color degree of an image when the discharge amount of ink droplets discharged from a nozzle of a head module of each color is not adjusted is specified for each head module of each array (step S). A correction voltage value of a drive signal for the discharge of the nozzle of the head module of each color, which is suitable to return the specified color degree to '0', is calculated (step S) and each corresponding nozzle is driven by the drive signal of the correction voltage value.

Ink discharge amount adjuster for each color of line inkjet printer

An image forming apparatus includes a controller configured to adjust ink ejection amounts from nozzles in a downstream nozzle array on a basis of a bypassing air flow degree. The bypassing air flow degree is calculated based on an ejection density of ink ejected from nozzles in an upstream nozzle array on a recording medium and indicates a generation degree of a bypassing air flow generated when a transfer air flow generated by transfer of the recording medium bypasses a self-generated air flow generated by ink ejected from the nozzles in the upstream nozzle array. The downstream nozzle array is a nozzle array located downstream in a transfer direction among a plurality of nozzle arrays. The upstream nozzle array is a nozzle array located upstream in the transfer direction among the plurality of nozzle arrays.

When reading the first document sheet, light intensity reference data is acquired by sampling a white reference plate while acquiring light intensity reference auxiliary data indicative of the light intensity of a light source lamp by sampling an auxiliary white reference plate. Then, just before reading the second or subsequent sheet, the auxiliary white reference plate is sampled to acquire the latest light intensity auxiliary data, followed by calculating the change amount from the light intensity reference auxiliary data. The change amount is used to correct the light intensity reference data separately for each picture element by referring to the profile data in which is stored the change amount of the sample value of each picture element corresponding to the change amount of the light intensity, followed by performing the shading compensation. By this configuration, it is possible to perform shading compensation in correspondence with the actual light intensity reduction.

Image reading apparatus having dual white reference plate and image reading method for effectively performing shading compensation

A controller reads out image data of an area frame that a user has drawn on an original and accurately extracts the area frame by removing noise from the read-out image data to divide image data of an area outside the area frame and image data of an area inside the area frame into separate stencils, according to a separation program. It is therefore possible to execute a separation process desired by the user without increasing costs and man-hours and with easy operations not making the user feel troublesome.

Stencil printing machine with a plurality of drum units and method of controlling the same

In an image processing system, whether relevant pixels in the character image information obtained by reading an original on which characters have been recorded are object pixels to be subjected to enhancement processing is determined. The relevant pixel is determined to be an object pixel when the density of the relevant pixel is not lower than a first threshold value higher than the density of the background of the border of the original and not higher than the density of a thinnest line in lines which form the characters and is not higher than a second threshold value not lower than the density of a thinnest line in lines which form the characters and the relevant pixel is determined to be a thin line pixel forming a part of a thin line image.

Image processing system

An image processing apparatus corrects degradation of an image of a pair of spread pages of a bound book placed on a document table. The image processing apparatus includes a height obtaining unit which obtains a plurality of heights, above the document table, of a plurality of points of the pair of spread pages, based on a contour of the pair of spread pages which appears in the image, and an image correcting unit which corrects the degradation of the image based on the plurality of heights obtained by the height obtaining unit. The degradation may be unevenness of lightness, deformation, a blur, or the like.

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Ibaraki-ken, Japan

Takashi Ebisawa