An image forming apparatus includes a setting unit configured to set a thinning amount smaller than one pixel for each line data in a high density area in image data, a comparison unit configured to compare the thinning amount set by the setting unit with a predetermined threshold, and a processing unit configured to execute, based on a result of comparison by the comparison unit, a thinning process by using a thinning amount larger than the thinning amount set by the setting unit or a thinning amount smaller than the thinning amount set by the setting unit as for M pixels out of N pixels (N>M) contained in the line data, and a thinning process by using the thinning amount set by the setting unit as for the rest of the N pixels contained in the line data.

According to an aspect of the invention, an image processing device includes a storage that stores character information, which is information affecting legibility of a character, on a character-by-character basis, and circuitry configured to determine a toner saving ratio for each character contained in a to-be-printed image so that legibility of the character achieves a preset target value at the determined toner saving ratio by assessing the legibility of the character based on the character information.

Each of the discharge head 3wu, 3wd discharges the ink dots of white to the web 10. The discharge heads 3wu, 3wd are controlled to share the discharge of the white ink for the web 10. As a result of such a control, the ink dot discharged to the web 10 from the discharge head 3wd is interposed between two ink dots successively discharged to the web 10 from the nozzle 31 of the discharge head 3wu in the X direction. The ink dot discharged to the web 10 from the discharge head 3wu is interposed between two ink dots successively discharged to the web 10 from the nozzle 31 of the discharge head 3wd in the X direction. That is, each of the discharge head 3wu and the head 3wd only has to be able to continuously discharge the ink in the cycle, which is twice the cycle Tcy, and should not necessarily be able to continuously discharge the ink in a short time.

An image processing method includes reading a document on which a halftone-processed image is printed, performing smoothing processing on image data acquired by reading the document, setting a target region of a predetermined size to the smoothed image data and then calculating a degree of variation in signal values of a plurality of pixels included in the target region, determining a brightness correction amount for the target region based on the calculated degree of variation and the signal values of the plurality of pixels included in the target region, and performing brightness correction on the target region in the image data acquired by reading the document, based on the determined brightness correction amount.

An image processing apparatus acquires target image data generated by optically reading a sheet. The sheet includes an original image and an added image. The added image is added on the sheet. The apparatus specifies, from the target image, an added region surrounded by a surrounding line. The apparatus specifies a written target in the added region. The apparatus generates partially-erased image data and supplementary data by using the target image data and a result of the specifying of the written target. The partially-erased image data represents a partially-erased image that is based on the target image with an image inside the added region being erased. The supplementary data concerns the added image. The apparatus generates an image file including the partially-erased image data and the supplementary data so that the partially-erased image and supplementary information can be reproduced in selective one of a simultaneous manner and an independent manner.

An image processing apparatus acquires target image data generated by optically reading a sheet. The sheet includes an original image and an added image. The added image is added on the sheet. The apparatus specifies, from the target image, an added region surrounded by a surrounding line. The apparatus specifies a written target in the added region. The apparatus generates partially-erased image data and supplementary data by using the target image data and a result of the specifying of the written target. The partially-erased image data represents a partially-erased image that is based on the target image with an image inside the added region being erased. The supplementary data concerns the added image. The apparatus generates an image file including the partially-erased image data and the supplementary data so that the partially-erased image and supplementary information can be reproduced in selective one of a simultaneous manner and an independent manner.

An image forming device includes: a rasterizing section, a resolution converting section and a thinning section. The rasterizing section generates, by rasterization, image data having any one of standard resolution, resolution higher than the standard resolution and resolution lower than the standard resolution. The resolution converting section converts the resolution upon rasterization for the generated image data having the higher or lower resolution than the standard resolution into the standard resolution. The thinning section thins the image data having the standard resolution. When thinning the image data of which the resolution is converted higher than upon rasterization in the resolution converting section, the thinning section adjusts thinning strength to become larger upon thinning than when thinning the image data of which the resolution upon rasterization is kept as it is.