Abstract

Laser printers are steadily advancing toward high speed and high resolution. The rotation speed of a polygonal mirror for scanning beams and the data rate for printing are going to be over practical limits. The simultaneous scanning of multiple beams in an array is an effective method to eliminate these problems. The arrayed multiple beams can be generated by devices such as grating, Wollaston prisms, fiber array and laser diode array. In any of these devices, the focused arrayed spots have a period of several tens of times larger than the spot diameter. To produce consecutive scan lines using these devices, we proposed the slant scanning method, where the arrayed multiple beams are arranged in a slant angle to the scanning direction.⁽¹⁾ There is another method called an interlacing scanning method.⁽²⁾ But for realizing high speed and high resolution laser printer, the slant scanning method has a greater advantage in that it is applicable to the case in which the number of beams is large because the multiple beams pass in the vicinity of the scanning plane and the optical aberrations are kept small. We demonstrated high performance printings which are, for example, print speed 1,168 mm/sec with print density 9.45 dot/mm(i.e.240 dot/inch) using two beams generated by a Wollaston prism and print speed 825.5 mm/sec with print density 23.6 dot/mm(i.e.600 dot/inch ) using five beams generated by a grating, both of which have a wide print width of 431.8 mm.

© 1998 Optical Society of America