Abstract: A source data latch circuit for latching data which are read-in from a DRAM is provided. A data latch circuit for latching one-byte data generated by a CPU and an overflowing bit storing circuit for storing overflowing data through a three-bit shift are provided. At a composing circuit, data latched by the latch circuit at a previous time and stored in the overflowing bit storing circuit and the present data latched by the latch circuit are composed. At an OR circuit, the composed data and data with respect to which an OR is obtained are written into RAM.

Abstract: The present invention is directed to the provision of a sheet feeder unit mounted in a copying machine or the like having a sheet transport mechanism. The sheet feeder unit feeds sheets to the sheet transport mechanism, and the sheets fed into the sheet transport mechanism are transported by the sheet transport mechanism. Each sheet being transported by the sheet transport mechanism is detected by a pair of sensors disposed with a prescribed space provided between each other, and the sheet transporting speed is calculated from the time in which the sheet travels the distance between the two sensors. The sheet feeding condition is set on the basis of the sheet transporting speed of the sheet feeder unit so that the sheets fed from the sheet feeder unit do not overlap each other.