Patent ID: 8323017

Claim:
Apparatus for producing an object by sequentially forming thin layers of a construction material one on top of the other responsive to data defining the object, the apparatus comprising: a movable set comprising at least four printing heads, each having a surface formed with a plurality of output orifices offset from each other in a first direction by a first distance, the first, second, third, and fourth printing heads of the set being placed in that order in a second, scan, direction substantially perpendicular to the first direction; and a controller adapted to scan the movable set with respect to a support surface in the second, scan, direction and to control the printing heads to dispense the construction material through each of their respective orifices responsive to the data, such that each orifice dispenses material along a construction line separated by said first distance from the line along which a neighboring orifice in a same head dispenses its material, wherein the orifices in the second printing head are offset from those in the in the first printing head, in the first direction, by one half the first distance, such that they dispense the construction material along lines substantially equidistant from lines along which construction material is dispensed by the first printing head, and wherein the orifices in the third and fourth printing heads are so positioned that they dispense construction material along lines equidistant from the adjacent lines along which material is dispensed by the first and second heads.