A system and method are provided for a printer which divides raw bands of print data corresponding to a page to be printed into a plurality of sub-bands. By generating sub-bands of print data for each page, a segmented page frame buffer can be used to store the print data non-contiguously in the memory segments of the buffer so that the memory may be used more efficiently. Also, a compressed data line representative of blank data is stored in the memory for eliminating redundant operations of processing and storing blank data lines (data lines containing no data). As a result, every time a blank data line is detected, the compressed blank data line stored in the memory can be pointed to and the performance of the printer is enhanced by reducing the printing time.

A color image forming apparatus includes a carrier belt which runs along a transport path of a recording medium to transport the recording medium. A number of image-forming sections are aligned in the transport path. Each of the plurality of image-forming sections forms a toner image of a corresponding color included in an image signal. A plurality of transfer units are provided, with each being disposed to oppose a corresponding one of the number of image-forming sections. Each of the number of transfer units transferring the toner image of the corresponding color to the recording medium. A fixing unit is provided that fixes the toner image to the recording medium. A controller is provided that detects a number of colors in the image signal. The controller sets one set of speeds from a plurality of different sets of speeds in accordance with the number of colors. Each set of speeds includes a speed of the carrier belt, a speed at which each of the image-forming sections forms a respective toner image of a corresponding color, and a speed of the fixing unit. The speed of the carrier belt, the speed at which each of the image-forming sections forms a respective toner image of a corresponding color, and the speed of the fixing unit of any one respective set of speeds are substantially equal to each other.

A color image forming apparatus provides the prolonged life of the photosensitive drums, carrier belt, and toner of the respective colors and improves the quality of the printed color image. A carrier belt transports a recording medium placed thereon so that the recording medium passes through a plurality of printing mechanisms which print images of different colors on the recording medium in superposition. Each printing mechanism prints an image of a corresponding color. The printing mechanism is adapted to be moved into its operative position where the photosensitive drum of the printing mechanism is in contact with the carrier belt to print the image on the recording medium, and into its non-operative position where the photosensitive drum of the printing mechanism is not in contact with the carrier belt. A controller receives print data from a host device such as a personal computer and checks each page of the print data to determine whether any one of a predetermined plurality of colors is missing in the page. If a particular color is missing in the print data, then the controller outputs an UP signal to a positioning mechanism for a corresponding printing mechanism. If the color is not missing, then the controller outputs a DOWN signal. The printing mechanism moves a corresponding printing mechanism into the operative position if the UP signal is received from the controller and into its operative position if the DOWN signal is received.

While performing main scanning in which a head having a plurality of nozzles that eject ink is moved in prescribed forward and reverse main scanning directions relative to a print medium, print images are printed on the print medium by forming dots in each pixel aligned in the main scanning direction in accordance with print data. The dot formation position misalignment amount for each nozzle is corrected using image pixel value data indicating the existence of image pixels comprising images and adjustment pixel value data indicating the existence of adjustment pixels in which dots are not formed.

An output apparatus comprises a calculation unit for analyzing information received page by page while dividing the information into a plurality of areas to calculate bit map development time for each area, a discrimination unit for determining whether that area having the longest bit map development time calculated by the calculation unit can be developed into a bit map or not with a presecured minimum capacity of development memory, and a control unit for controlling the capacity of the secured development memory in accordance with that longest bit map development time.