| 摘要 |
PURPOSE:To achieve higher densities of picture elements by letting the pulse number in one scanning period of the smaller frequency out of various pulses of reading and writing coincide with the maximum capacity that can be utilized of a memory device. CONSTITUTION:In the case of making the diameters of separating and exposure drums 1, 2 the same and doubling the reproduction magnification in the line direction, the read speed, i.e., the output pulse frequency of a frequency divider 40, is set at 60K Hz and the write speed, i.e., that of a frequency divider 38, is set at 120K Hz or other. Further, if the maximum speed determined by an A/D converter 31 for which the write speed is used is 200K Hz, the write speed is made 200K Hz. In the case of setting the reproduction magnification large in this way, arrangement is so made that the read speed which is low as compared to the write speed is able to make maximum possible use of the capacity of a memory device 33 in one line. In the case of scale down, the write speed is conversely made smaller than the read speed and writing is done in a P-ROM 42. Thereby, the maximum possible use of the memory device may be made and picture element densities increased. |
