PRINTHEAD HAVING HEATED SHIELD PLATE
FIG16 is a top perspective of part of the shim
The Invar shim 66, shown in isolation in FIG16, provides a stable platform for each row of printhead chips 70 with negligible thermal expansion during use. The shim 66 has a comparable thickness to the printhead chips 70 (e.g. about 100 to 1000 microns in thickness). Effectively, the Invar shim 66 enables construction of long printheads based on a monolithic manifold to which a plurality of printhead chips can be mounted.
perspective view
20
shield plate
40
channels channel
52
lower surface
29
flanges flange
68
voids
30
vent holes
18
PCB
25
manifold
24
lead retainer
17
main body
72
longitudinal shim rib
80
contact pads contact pad
22
leads lead
16
second row second rows
27
cover plate
41
sidewalls
44
dividing wall
75
define opposite wings
13
contacts contact
67
shim trusses
69
longitudinal shim slots
79
encapsulant
3
casing
74
step
['1. An inkjet printhead (1) comprising: a manifold (25) having a plurality of ink outlets (50) defined in a manifold surface; a plurality of printhead chips (70) mounted to the manifold surface (52) via a shim (66), the printhead chips being aligned with the ink outlets; a PCB (18) mounted to the manifold surface and offset from the ink outlets, the PCB being electrically connected to the printhead chips, wherein a lower surface of the PCB is coplanar with a lower surface of the shim; and a shield plate (20) bonded to the PCB and part of the shim, the shield plate covering the PCB, wherein: the shield plate has one face in thermal contact with the PCB and an exposed opposite face defining a lower surface of the printhead; and the shim has at least one void region (68) offset from the printhead chips, the void region thermally isolating part of the shield plate from the manifold.', '6. The inkjet printhead of claim 5 comprising first and second rows of printhead chips, the first row of printhead chips having a respective first PCB and the second row of printhead chips having a respective second PCB, wherein the first and second PCBs are positioned at opposite distal longitudinal sides of the first and second rows of printhead chips.']