Hoechst Aktiengesellschaft

Gerhard Spingath

Helmuth Haberhauer

The invention relates to a developing apparatus which, in a preferred embodiment, includes a first charging device comprising a rotating device, preferably designed as a brush having a core which is connected to a first voltage source. A single component developer is fed, from a developer feed unit, to the first charging device, by means of a metering roller. The charging device is enclosed by a trough, which is connected to a voltage source. A scraper in glancing contact with the bristles of the first charging device imparts an additional charge to the developer by tribo-electricity and sprays particles of developer on the bristles onto a developing roller. A second charging device, in the form of a second brush having a core connected to said voltage source may also be used. The grid is then positioned between the charging devices. A second scraper functions, in a similar manner, in conjunction with the second charging device. The developing roller is connected to a second voltage source and particles of developer, which form a uniform layer on the peripheral surface of the developing roller, are attracted by a latent charge image on a recording medium, to thereby obtain a developed charge image.

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Wiesbaden, Germany

Gerhard Spingath