Olivetti-canon Industriale S.p.a.

Ing C. Olivetti C., S.p.a.

Riccardo Forlani

Renato Bortolin

Bruno Cestari

Michele Olivero

Roberto Guelfo

Piero Gontero

Riccardo Dal Bianco

In an electrostatic image developing device for electrical photocopiers, a magnetizable one-component toner, initially contained in a removable container, is fed, by the action of a rotating flexible strip, through a development chamber towards a rotating non-magnetic development roller surrounding a number of stationary permanent magnets, forming on it a magnetic brush, whose thickness is controlled by a non-magnetic flexible blade pressed against the surface of the development roller; the development chamber is fitted with three stirring bars made of non-magnetic material, each bar describing a different closed path in different zones of the development chamber in such a way as to avoid the formation of lumps and to maintain the correct fluidity of the toner. In addition, a metallic wire is fitted in the development chamber and acts as a sensor device to detect when the removable container is nearly empty of toner.

Electrostatic image developing device having toner flow control and

Fixing device for copying machines in which a linear heating element, positioned transversely to the movement of the sheet of paper, is immediately followed by a shoulder projecting beyond the heating element towards a pressure roll in order to give the paper an opposite curl to that spontaneously adopted. The sheets of paper emerge from the fixing device having retained their flat form. Because of the high specific pressure on the shoulder fixing is improved.

Fixing device for improving the flatness of sheets discharged therefrom

An image is fixed to a sheet of paper, in an image reproducing machine in a fixing station (GF). This uses heat and pressure to fix the image. A pair of straightening rolls (24, 26) downstream of the fixing station apply tension to the sheets in the direction of advance and forward them in a direction which inclines by a predetermined angle of correction with respect to the direction (21) with which the sheets leave the fixing station. The straightening rolls form a nip (62) therebetween and this may extend around a portion of the periphery of one of the rolls such that sheets passing therethrough are bent in an opposite direction to their natural direction of curl.

Device for eliminating the curl of sheets emerging from a fixing station

The photocopier uses a development process employing a magnetic brush formed on a rotating sleeve (102) of non-magnetic material in which a system of permanent magnets (108) rotates. The outer surface of the sleeve is subjected to a sandblasting process after grinding in order to create a very uniform finely roughened surface in order to make the thickness of the toner layer forming the magnetic brush constant. The photocopier also employs a toner fixing system operating cold and under pressure by means of a pair of rollers (56, 58) of different diameter rotating at the same angular speed in order to create slippage of the upper roller relative to the lower roller for the purpose of obtaining perfectly flat copies. The copier also contains a single circuit board (80) for the low voltage and high voltage supply.

Electrophotographic copier

A magnetic brush (10) comprises a sleeve (16) of nonmagnetic material which rotates about magnets (14) fixed on a shaft (12) which rotates in the opposite direction to the sleeve. A toner container (20) adjacent to the sleeve feeds the toner (T) on to the outer surface of the sleeve through a slit (36) which extends over the entire length of the sleeve. In order to prevent the formation of lumps of toner at the feed slit and break up any lumps already in the container, a portion (32) of the base wall of the toner container is of arcuate shape and is spaced from the sleeve by a distance equal to the thickness of the toner layer (52) on the sleeve. The arcuate wall defines the toner feed slit (36) in cooperation with a side wall (60) of the container. A baffle (26) divides the container into a main chamber (42) and secondary chamber (46) which communicate with each other by way of a narrow passage between the baffle and the arcuate wall (32). The magnetic field of the brush magnets urges the toner along the arcuate wall in order to fill the secondary chamber to a certain level, from which it emerges from the feed slit. Any lumps of toner or foreign particles are blocked by the dividing baffle. Lumps of toner are agitated by the variations in the magnetic field, so that they gradually disintegrate to allow recovery of the toner.

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Turin, Italy

Riccardo Forlani