Abstract: An image forming apparatus includes a controller for controlling at least a photoconductor drum and a fuser to operate independently of each other. In such an apparatus, at least one of the photoconductor drum and the fuser is provided with an electrical or mechanical member, such as a clutch for selectively coupling a driving system and a rotary member, which is operative independently, and the controller provides such a control that the electrical or mechanical members of the photoconductor drum and the fuser are responsive to signals applied thereto to start or stop the operations independently in timing, respectively.

Abstract: A printer control system receives ruled line data for the entire printing region with respect to the row direction included in ruled line print data, and image data included in image print data in a plurality of blocks from a host system, accumulates the blocks of the ruled line data and those of image data until all the ruled line data and all the image data are received, and then converts the print dot density of the accumulated ruled line data and image data into a print dot density matching an internal printer thereof. Therefore, the ruled line print data and the image print data are printed correctly without dislocation with respect of the row direction.

Abstract: In a printing apparatus, a raster buffer for storing dot image data is divided into three layers in the direction of auxiliary scanning, and the respective layers are assigned to a writing layer in which a font pattern read from a font memory is written, a reading layer from which dot image data that have been written are read, and a write-waiting layer in which a font pattern that has overflown the writing layer is written, with the writing layer and the write-waiting layer having a capacity for storing a character having the biggest size among those which are used frequently.

Abstract: A font converting device converts (dot density conversion) a down-line load font received through an interface device into a font represented by a dot matrix of the same size as that of a resident font stored in first memory and stores the converted down-line load font in a second memory. A control circuit selectively reads the fonts of the first memory (resident font) or the fonts of the second memory (converted down-line load font) in conformity to a font code included in print data, edits dot image data, and then provides the same to a printing unit to be controlled, namely, a printer in a narrow sense. Only the rarely used down-line load font is subjected to dot density conversion so that the print dot density of the converted down-line load font coincides with that of the print dot density of the printer to be controlled, while a frequently used font of a print dot density coinciding with that of the printer is stored as resident font.