1. Field of the Invention
This invention relates to an image processing apparatus for processing printing information from a host computer or the like, and more particularly, to an image processing apparatus which receives coded printing information, generates a pixel dot pattern (bit map data), and performs printing using a printing unit.
2. Description of the Related Art
In a printing unit of this kind, particularly a laser-beam printer, it is in some cases necessary to perform warm-up operations of respective mechanical units. For example, such operations include stabilization of the revolution speed of a polygon mirror, stabilization of the temperature of a fixing unit, and the like, before starting a printing operation.
FIGS. 1 and 2 are characteristic diagrams showing the starting and transition phases of a conventional warm-up processing. In FIGS. 1 and 2, the ordinate represents the various operational states, and the abscissa represents time.
As shown in FIG. 1, the warm-up processing is started at a timing TM1 when development in bit map data has been terminated. Alternatively, as shown in FIG. 2, when first data has been received from a host computer, that is, at a timing TM2, the warm-up processing for a printer unit is started, thereby increasing the speed of the warm-up processing.
In the above-described conventional approaches, however, a considerable amount of waiting time is needed before printing is initiated. For example, if subsequent data are not input for a certain time period after receiving the first data from the host computer, or if a very long time period is needed for processing the data until all printing data have been received, since warm-up processing for the printer engine is started when the first data has been received, a waiting state is provided while the temperature of a fixing unit is in an operational state, causing a considerable burden on respective units from a viewpoint of power consumption as well as from a viewpoint of life.