Image processing apparatus, image forming apparatus and image processing method

An image processing apparatus, comprising:

• a line memory capable of writing and reading image data of one line;
• a write/read controller for controlling writing and reading of the image data of one line in and from the line memory;
• a white line determiner for determining whether or not an image corresponding to the image data of one line being written in the line memory by the write/read controller is a white line;
• an image processor capable of performing a specified image processing on the image data of one line read from the line memory by the write/read controller;
• a white data storage storing white data;
• and
• an image processing controller for controlling to generate an operation clock used in the image processor and cause the image processor to perform the specified image processing for the image data of one line determined not to be a white line by the white line determiner and controlling to stop generating the operation clock and read the white data from the white data storage for the image data of one line determined to be a white line by the white line determiner.