Patent ID: 7422300

Claim:
An image forming apparatus, comprising: an ink application device which applies droplets of ink having sizes different from each other to a recording medium; a treatment liquid application device which applies treatment liquid which causes the ink to increase in viscosity or solidify, by reacting with the ink; an image processing device which generates image data of multiple values from an input image, the multiple values corresponding to the sizes of the droplets of the ink; a block dividing device which divides an image region to be formed on the recording medium according to the image data into a plurality of blocks, each of the blocks including a plurality of pixels; an evaluation value calculation device which calculates an evaluation value for each of the blocks for judging an application of the treatment liquid to each of the blocks, according to the image data; and a treatment liquid application control device which controls a mode of applying the treatment liquid to each of the blocks, by comparing the evaluation value with a previously established threshold value, wherein the evaluation value calculation device calculates the evaluation value according to the image data by adding an additional value, and the larger the size of the droplet of the ink to be applied to the recording medium is, the larger the additional value to be added becomes.