Printhead chassis assembly

A printhead chassis assembly for a chip based printhead, comprising:

• a chassis which supports two spaced apart bearing moldings between which extend a feed roller and an exit roller;
• the chassis supporting a duct cover in which is formed a number of inlet ports which are adapted to receive liquid ink;
• the duct cover sealing against a distribution molding, the distribution molding having a longitudinal axis and a number of elongated ducts running in parallel along the axis, each duct being associated with a port;
• all of the ducts are sealed against and in fluid communication with an upper layer of a laminated ink distribution structure;
• and
• a longitudinal air duct within which is located an air valve molding formed as a channel with a series of apertures in its base;
• the apertures corresponding to air passages formed in the air duct so that the apertures can be brought into and out of alignment with the passages to selectively allow pressurized air through;
• the air valve molding reciprocating within the air duct;
• a spring maintaining a sealing inter-engagement of a bottom of the air valve molding with the base of the air duct to prevent leakage;
• the laminated ink distribution structure having a first layer in which is formed a number of first holes, each first hole being in registry with a lower duct portion;
• the laminated ink distribution structure having a number of subsequent layers, each subsequent layer having vertical passages and transverse channels for bringing a fluid from a duct, via the first layer, to one of a number of printhead chips located as an array in a chip restraining layer;
• the chips arranged to print onto a sheet of media carried by the feed roller and the exit roller.