PRINTHEAD WITH NON-PRIMING CAVITIES FOR PULSE DAMPING

Abstract

A printhead for an inkjet printer that has a printhead integrated circuit (68) with nozzles for ejecting ink and a support structure (64, 174, 176) for supporting the printhead IC. The support structure having ink conduits (182) for supplying the array of nozzles. A plurality of cavities (200), each cavity having an opening that establishes fluid communication with the ink conduits, the openings being configured such that the cavities do not prime with ink when the ink conduits are primed from the ink supply. By leaving unprimed cavities throughout the support structure, any pressure pulses in the ink are damped by compression of the trapped gas pockets. Distributing the cavities rather than using one relatively large cavity, means that the pressure pulse is being damped along the length of the printhead IC, instead of allowing the pulse to travel the length of the ink conduit until it reaches the single damper and compresses the gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a front and side perspective of a printer embodying the present invention;

FIG. 2 shows the printer of FIG. 1 with the front face in the open position;

FIG. 3 shows the printer of FIG. 2 with the printhead cartridge removed;

FIG. 4 shows the printer of FIG. 3 with the outer housing removed;

FIG. 5 shows the printer of FIG. 3 with the outer housing removed and printhead cartridge installed;

FIG. 6 is a schematic representation of the printers fluidic system;

FIG. 7 is a top and front perspective of the printhead cartridge;

FIG. 8 is a top and front perspective of the printhead cartridge in its protective cover;

FIG. 9 is a top and front perspective of the printhead cartridge removed from its protective cover;

FIG. 10 is a bottom and front perspective of the printhead cartridge;

FIG. 11 is a bottom and rear perspective of the printhead cartridge;

FIG. 12 shows the elevations of all sides of the printhead cartridge;

FIG. 13 is an exploded perspective of the printhead cartridge;

FIG. 14 is a transverse section through the ink inlet coupling of the printhead cartridge;

FIG. 15 is an exploded perspective of the ink inlet and filter assembly;

FIG. 16 is a section view of the cartridge valve engaged with the printer valve;

FIG. 17 is a perspective of the LCP molding and flex PCB;

FIG. 18 is an enlargement of inset A shown in FIG. 17;

FIG. 19 is an exploded bottom perspective of the LCP/flex PCB/printhead IC assembly;

FIG. 20 is an exploded top perspective of the LCP/flex PCB/printhead IC assembly;

FIG. 21 is an enlarged view of the underside of the LCP/flex PCB/printhead IC assembly;

FIG. 22 shows the enlargement of FIG. 21 with the printhead ICs and the flex PCB removed;

FIG. 23 shows the enlargement of FIG. 22 with the printhead IC attach film removed;

FIG. 24 shows the enlargement of FIG. 23 with the LCP channel molding removed;

FIG. 25 shows the printhead ICs with back channels and nozzles superimposed on the ink supply passages;

FIG. 26 in an enlarged transverse perspective of the LCP/flex PCB/printhead IC assembly;

FIG. 27 is a plan view of the LCP channel molding;

FIGS. 28A and 28B are schematic section views of the LCP channel molding priming without a weir;

FIGS. 29A, 29B and 29C are schematic section views of the LCP channel molding priming with a weir;

FIG. 30 in an enlarged transverse perspective of the LCP molding with the position of the contact force and the reaction force;

FIG. 31 shows a reel of the IC attachment film;

FIG. 32 shows a section of the IC attach film between liners; and

FIG. 33 is a partial section view showing the laminate structure of the attachment film.

Claims

1. A printhead for an inkjet printer, the printhead comprising: a printhead integrated circuit (IC) with an array of nozzles for ejecting ink;a support structure for supporting the printhead IC, the support structure having ink conduits for supplying the array of nozzles with ink and an ink inlet for connection to an ink supply; and,a plurality of cavities, each cavity having an opening that establishes fluid communication with the ink conduits, the openings being configured such that the cavities do not prime with ink when the ink conduits are primed from the ink supply.

2. A printhead according to claim 1 wherein each of the cavities is a blind recess such that the opening defines an area substantially equal to that of the blind end.

3. A printhead according to claim 2 wherein the openings each face one of the ink conduits only.

4. A printhead according to claim 3 wherein the openings are configured to inhibit ink filling the recess by capillary action.

5. A printhead according to claim 4 wherein the openings to each respective cavity have an upstream edge and a downstream edge, the upstream edge contacting the ink before the downstream edge during initial priming of the ink conduits from the ink supply, and the upstream edge having a transition face between the conduit and the cavity interior, the transition face being configured to inhibit ink from filling the cavity and purging the gas by capillary action during initial priming of the ink conduit.

6. A printhead according to claim 5 wherein the printhead is a pagewidth printhead and the support structure is elongate with the inlet at one end and the outlet at the other end, and the ink conduits have channels extending longitudinally along the support structure between the inlet and the outlet, and each of the channels have a series ink feed passages spaced along it to provide fluid communication between the channel and the printhead IC.

7. A printhead according to claim 6 wherein the ink feed passages join to the channel along a wall of the channel that is opposite the wall including the openings to the cavities.

8. A printhead according to claim 7 wherein the support structure is a liquid crystal polymer (LCP).

9. A printhead according to claim 8 wherein the support structure is a two-part LCP moulding with the channels and the feed passages formed in one part and the cavities formed in the other part.

10. A printhead according to claim 9 wherein the support structure has a plurality of printhead ICs mounted end to end along one side face.

11. A printhead according to claim 10 wherein the printhead ICs are mounted to the side face via an interposed adhesive film having holes for fluid communication between the ink feed passages and the printhead ICs.