Fujitsu Corporation

Masanori Tokuhisa

Masato Ishii

Hirohiko Kubo

A toner quantity detecting system has a toner quantity detector (4c) and is capable of accurately detecting the decrease of the quantity of toner contained in the toner container of the developing unit of an image recording apparatus to an upper threshold quantity and to a lower threshold quantity regardless of the inherent output characteristic of the toner quantity detector (4c) and determining a prewarning voltage (E.sub.nep) representing the upper threshold quantity and a warning voltage (E.sub.emp) representing the lower threshold quantity so that the difference between the prewarning voltage (E.sub.nep) and the warning voltage (E.sub.emp) is sufficiently large. The prewarning voltage (E.sub.nep) and the warning voltage (E.sub.emp) are determined on the basis of the inherent output characteristic of the toner quantity detector (4c). The output voltage (E.sub.s) of the toner quantity detector (4c) is compared with the prewarning voltage (E.sub.nep) and the warning voltage (E.sub.emp) to provide a prewarning signal (NAL) upon the reduction of the quantity of the toner to the upper threshold quantity and to provide a warning signal (EAL) upon the reduction of the quantity of the toner to the lower threshold quantity.

Toner quantity detecting system for an image recording apparatus, a

An electrophotographic recording apparatus including a light-sensitive drum for carrying toner images developed thereon, and a transfer unit arranged at a prescribed distance from the light-sensitive drum for transferring the toner images from a light-sensitive drum to the image recording paper. The transfer unit has a charging wire electrode for electrically charging the paper and a generally inverted U-shaped housing having spaced sidewalls with respective bottom edges. A separator is provided for separating the paper from the light-sensitive drum as the paper travels along a conveying path and comprises a paper separating plate extending from the downstream one of the bottom edges of the housing of the transfer unit in the downstream direction of the travel of the paper along the conveying path side thereof, with and the housing of the transfer unit is grounded. The paper separating plate has a distal end having a saw tooth shape along the length thereof, as measured transversely to the conveying path.

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Kawasaki, Japan

Masanori Tokuhisa