Sharp Kabushiki Kaisha Corporation

Tsuyoshi Takeno

Yoshiyuki Nakai

Fumio Shimazu

Yasushi Adachi

Tatsuya Tanaka

Masao Narumiya

Toshio Takehara

A gradation control method in a color thermal transfer printer is adapted to express one pixel by a dot matrix with two rows and two coles, control a density value of one dot with a time for energizing a heating element of a thermal head, and carry out mask patterning for plotting only one of four dots when the gradation of each color for one pixel is not more than a prescribed value while plotting only two of the four dots when the gradation is in excess of the prescribed value. At this time, employed is a mask pattern of necessarily plotting cyan and magenta on dots which are different from each other. A picture quality improving method in a staggered printing system is adapted to plot a noted dot when at least one of such conditions that density data of the noted dot is in excess of a prescribed density value and that density data of any of four dots most approximate to the noted dot is not more than a prescribed low density value is satisfied, even if the noted dot corresponds to that to be masked.

Methods of gradation control and picture quality improvement in a

An image forming apparatus which includes a bucket for accommodating a cartridge holding a roll of a photosensitive sheet and a take-up shaft for taking up the photosensitive sheet after use, the bucket having an exposure plate disposed above the cartridge, a slidable means engageable with a slidable means provided on the image forming apparatus so as to enable the bucket to be slidably mounted in and dismounted from the image forming apparatus, and a positioning means for securing the exposure plate in its optically proper position.

Image forming apparatus equipped with a bucket for accommodating a

Growing community of inventors

Yamatokoriyama, Japan

Tsuyoshi Takeno