Inkjet printing apparatus and variable-density correction method
AssigneeSCREEN Holdings Co., Ltd.
InventorYoshikazu Ichioka
Life of this patent
Estimating the term…
Abstract
First, shading charts are printed on a surface of a recording medium. Then, a plurality of captured images is acquired for a region of the same density of the shading charts printed on the recording medium. At this time, the amounts of displacement in the position of the recording medium in the main scanning direction, which is the direction of arrangement of nozzles, are also detected. Then, one super-resolution image with a higher resolution than the captured images is generated on the basis of the captured images and the amounts of displacement in the position of the recording medium in the main scanning direction. Thereafter, a variable-density correction amount is calculated for each of the nozzles on the basis of the generated super-resolution image.
Claims13
An inkjet printing apparatus for printing an image on a surface of a recording medium, comprising:
- a head having a plurality of nozzles arranged in a main scanning direction, said plurality of nozzles ejecting ink to a surface of a recording medium;
- a transport mechanism that transports a recording medium relative to said head in a sub-scanning direction orthogonal to said main scanning direction;
- an image capturing part that captures an image of a surface of a recording medium at an image capturing position located downstream of said head in said sub-scanning direction;
- a detector that detects an amount of displacement in position of a recording medium in said main scanning direction at said image capturing position;
- and
- a controller connected to said head, said transport mechanism, said image capturing part, and said detector,
- said controller including:
- a chart print instruction part that controls and causes said head and said transport mechanism to print a shading chart whose density changes in a stepwise fashion in said sub-scanning direction on a recording medium;
- an image acquisition part that controls and causes said image capturing part to acquire a plurality of captured images for a region of the same density of said shading chart;
- an ultra-resolution processing part that generates one super-resolution image with a higher resolution than said plurality of captured images on the basis of said plurality of captured images acquired by said image capturing part, and amounts of displacement in position of a recording medium in said main scanning direction acquired by said detector;
- and
- a correction amount calculation part that calculates a variable-density correction amount for each of said plurality of nozzles on the basis of said ultra-resolution image.
A variable-density correction method for an inkjet printing apparatus for printing an image on a surface of a recording medium by ejecting ink from a plurality of nozzles of a head arranged in a main scanning direction while transporting said recording medium relative to said head in a sub-scanning direction orthogonal to said main scanning direction,
- the variable-density correction method comprising:
- a) printing a shading chart whose density changes in a stepwise fashion in said sub-scanning direction, on a surface of a recording medium;
- b) acquiring a plurality of captured images for a region of the same density of said shading chart printed on a recording medium while detecting amounts of displacement in position of said recording medium in said main scanning direction;
- c) generating one super-resolution image with a higher resolution than said plurality of captured images acquired in said operation b), on the basis of said plurality of captured images and amounts of displacement in position of said recording medium in said main scanning direction;
- and
- d) calculating a variable-density correction amount for each of said plurality of nozzles on the basis of said super-resolution image.
Dependencies are inferred from the claim text.