Murata Machinery, Ltd.

Akinori Nishida

Takahiro Sasai

Shu Ikezaki

Takaaki Kamei

An image forming apparatus that prevents transfer defects such as the occurrence of white spots includes a photoreceptor drum, a transfer roller, a transfer bias application circuit that applies a transfer bias to the transfer roller, a static elimination needle that eliminates static of a recording paper, a static elimination bias application circuit that applies a static elimination bias to the static elimination needle, and a printer controller. The printer controller controls the static elimination bias application circuit so that a potential difference between the static elimination needle and the recording paper during the period from when a front end region of the recording paper passes by the static elimination needle until when a front end of the recording paper comes into contact with a conveyance guide becomes smaller than the potential difference during the period that the front end region of the recording paper passes by the static elimination needle.

Image forming apparatus with static elimination

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

A control device executes toner concentration control that controls an operation of a developing device such that a value of detection output detected by a concentration detecting device falls within a predetermined range. Moreover, when controlling drive of a first driving device, which drives at least an image carrier, and drive of a second driving device, which drives at least a fuser device, the control device executes operation control that starts the drive of the first driving device before the drive of the second driving device.

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Kyoto, Japan

Akinori Nishida