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

Gian D Dagna

Mario Buat

Franco Knirsch

Giovanni Gianolini

The device comprises a plurality of ink reservoirs, each connected to a number of nozzles (22) equidistant along a corresponding row. The nozzles connected to the various reservoirs are spaced apart vertically by at least one line space. The device can be used for printing different lines in parallel, moreover subdividing the length of the line, or for printing different zones of the sheet in facsimile. The ink is kept in circulation between the reservoirs and the nozzles by a common peristaltic pump which acts by a series of actuating elements on the discharge ducts for the inks in the reservoirs. The reservoirs may contain inks of different colors to permit printing in different colors or polychrome facsimile printing by additive or subtractive synthesis of the colors. The ink is conductive and is kept at earth potential, while electrodes (23) disposed outside the corresponding nozzles (22) are energized selectively to produce sprays of particles of ink from the nozzles. The ink contains a mixture of a dye of direct or solvent or acid type with a solution of water, electrolytic compounds, moistening agents, thickeners, preserving agents and antifoaming agent. The ink is prepared by mixing the compounds under agitation, then mixing in the dye until a predetermined acidity is obtained and finally filtering it and sealing it in the pack in the absence of air.

Ink-jet printing device

The head is provided for a conducting ink and comprises a closed container (14) carrying two electrodes and a nozzle (18). The head is removably mounted on a carriage (13) and is replaced when the ink is exhausted. The container (14) is divided into two cavities (71 and 72) which are in communication by way of an aperture (73, 74, 75) in order to cause ink to flow to the nozzle and to remove bubbles. To ensure that the bubbles do not cause an increase in the pressure in the container, causing the ink to discharge from the nozzle, the container comprises an expansible cavity formed by a bag-type diaphragm (83) and a compression spring (82) which tends to cause expansion of the cavity. The container is filled with ink, while holding the spring in a compressed condition. As the ink decreases, the spring expands, maintaining a slight depression within the container.

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Ivrea, Italy

Gian D Dagna