Developing system for bore matrix
AssigneeJarfalla Digital Filter Printer AB
InventorPer Sundström
Life of this patent
Estimating the term…
Abstract
A developing system for a bore matrix in a printer using toner in the form of a dry toner powder, and comprising a feeder brush (3) which receives toner from a toner container (1), a printer brush (5) receiving toner from the toner feeder brush (3) and transporting same through bores of a bore matrix (8) and down to a document (9) to be printed, and means (15) for charging the toner particles by mechanically rubbing the toner particles (2) against the printer brush (5), and in which a means (19) may be provided for ripping free the charged toner particles (2), so that said particles form a cloud (7) of charged toner particles (2) adjacent the bore matrix (8), which pass down to the document (9) to be printed through open bores of the bore matrix (8).
Claims12
A developing system for a bore matrix in a printing apparatus, in which toner (2) in the form of a dry powder is transported from a toner container (1) down onto a document (9) to be printed, and comprising a feeder brush (3) which receives toner (2) from the toner container (1) and which transports said toner to a printer brush (5) and further through bores of a bore matrix (8) down onto the document (9) to be printed, characterized in that the toner particles (2) are being charged in that the toner particles (2) are being mechanically rubbed against the printer brush (5) using charging ridges (15) arranged on a wall (22) adjacent the printer brush (5), and further comprising means provided closely in advance of the of the bore matrix, as seen in the direction of rotation of the printer brush (5), for ripping free the charged toner particles (2) by having the brush fibers naturally oscillate thereby providing a cloud (7) of charged toner particles (2) adjacent the bore matrix.
A developing system according to any of the preceding claims, characterized in that the brush fibers (11) are of a material which is semi-resistive, so that the charged toner particles (2) are attracted, easily releasable, to the printer brush (5) fibers (11) and, after having passed said means for ripping toner particles free, provide a cloud of negatively charged toner particles inside the printer brush (5), between the printer brush (5) fibers (11), which particles can be transported down through electrically opened bores of the bore matrix (8) and down onto the document (9) to be printed, whereas other toner particles are moved on by the printer brush (5).
A developing system according to any of the preceding claims, characterized in that it comprises several charging ridges (15) provided on the wall (22) extending along the periphery of the printer brush (5) for making the brush fibers oscillate thereby making the toner particles bounce to and from different fibers (11) thereby, assisted by the tribo-electrical effect, becoming charged (to a negative charge), while the fibers (11) of the printer brush (5) get a positive charge.
A developing system according to any of the preceding claims, characterized in that it comprises means (14, 17, 18) mounted in the rotational direction of the printer brush (5) in advance of the place where toner particles (2) are let down on the bore matrix (8) and adapted to remove toner particles (2) which, for various reasons, have been wrongly charged by the printer brush (5).
A developing system according to any of the preceding claims, characterized in that the fibers (11) of the feeder brush (3) and the printer brush (5) are of such length/diameter and stiffness that they get into natural vibration when the fibers (11) move past a rip off ridge (13, 15, 19), whereby said natural vibrations provide a movement of the toner particles (2) so that said particles become released from the fibres and are become charged or provide a cloud of toner, alternatively, for more easily being transferred down through the bores which are open in the bore matrix (8).
A developing system according to any of the preceding claims, in which the brush fibers are semi-resistive, characterized in that the system comprises, in the rotational direction of the printer brush (5), subsequent to the bore matrix (8), a metal surface (20) which is connected to a reference voltage and is adapted to drain the (positive) charge of the printer brush (5) at contact with the fibers (11) of said printer brush (5).
A developing system according to any of the preceding claims, characterized in that the feeder brush (3) is arranged to rotate at lower speed than the printer brush (5), and in that the feeder brush (3) is rotated only under short time intervals for transferring toner (2) to the printer brush (5).
A developing system according to any of the preceding claims, characterized in that both the feeder brush (3) and the printer brush (5) is formed with shafts (4, 6) of metal, which are connected to a certain reference voltage for making it possible to drain charges from the brushes.
Dependencies are inferred from the claim text.