Thermal expansion relieving support for printhead assembly
View Patent ↗A support member ( 3 ) forming part of a printhead assembly ( 1 ) for an inkjet printer with a plurality of printhead modules ( 2 ). The support member ( 3 ) has a first component ( 6 ) and a second component ( 5 ). The first component ( 6 ) mounts the printhead assembly ( 1 ) within an inkjet printer, and the second component ( 5 ) mounts the printhead modules ( 2 ). The second component ( 5 ) has a coefficient of thermal expansion closer to that of the printhead modules ( 2 ) than the first component ( 6 ) and the first component is bonded to the second component via intermediate resilient material ( 7 ). This allows the first component ( 6 ) to be a high strength low cost material such as steel, and the second component ( 5 ) can be selected so that the overall coefficient of thermal expansion of the support member is closer to that of the printhead modules. This reduces the difference between the thermal expansion of the printhead modules ( 2 ) and the support member ( 3 ). This, in turn, makes the printing alignment of individual modules ( 2 ) with their adjacent modules is easier. By including and intermediate layer of elastomeric material ( 7 ), the greater expansion of the metal component has less effect on the other component, and therefore less effect on the alignment of the printhead modules mounted to this component.
1. A support member for supporting a plurality of inkjet printhead modules within an inkjet printer, the support member comprising:
a first component and a second component, the first component adapted for mounting in the inkjet printer, and the second component adapted to mount the printhead modules, the second component having a coefficient of thermal expansion closer to that of the printhead modules than the first component; wherein,
the first component is bonded to the second component via an intermediate resilient material; such that,
the first component can expand more than the second component;
wherein the support member is configured as an elongate beam, the first component of the beam is an outer metal shell, and the second component of the beam is a core of silicon within the outer metal shell.
2. A support member according to claim 1 wherein the resilient material is an elastomeric layer interposed between the silicon core and the metal shell.
3. A support member according to claim 1 wherein the outer shell is formed from laminated layers of at least two different metals.
4. A support member according to claim 1 wherein the elongate beam has a length exceeding the width of print media to be printed by the inkjet printer.