Murata Machinery, Ltd.

Takaaki Kamei

Naritoshi Takamatsu

Akinori Nishida

In an image forming device, toner in a developing unit is efficiently utilized. A printing unit includes a developing unit, a toner cartridge, a photo-electronic sensor, a CPU and a counter. The toner cartridge replenishes toner to the developing unit at one time. The photo-electronic sensor detects toner in the developing unit. The CPU processes an output signal from the photo-electronic sensor to create comparison data, then compares comparison data with a predetermined threshold and issues an alarm when the comparison data exceeds the predetermined threshold. The counter counts the number of times that toner is replenished to the developing unit. The CPU changes the threshold to a level at which an alarm is hardly issued as the number of counts in the counter increases.

Image forming device and image forming method

An image forming apparatus in which a drum unit or a developing unit can be individually replaced, and the efficiency of an operation of providing the developing unit with developer or of an operation of removing the developer from the developing unit can be improved includes a supplying roller including a magnetic roller and a developing sleeve arranged on an outer circumference of the magnetic roller. A fixing member is attached to an axial portion of the magnetic roller. The supplying roller can be removably attached to a side of a photoconductive drum by the fixing member, and at the same time, a pole position of the magnetic roller relative to the photoconductive drum can be fixed.

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Kyoto, Japan

Takaaki Kamei