Capping mechanism driven by paper transport
View Patent ↗This invention concerns a printhead capping mechanism for preventing evaporation of ink from a printhead when it is not in use. The invention has utility, for instance, in a color printer which uses a drop-on-demand inkjet printhead. The mechanism includes a cap fitted with an elastomeric seal to seal against the face of the printhead, and a sponge to catch drops ejected from the printhead during the nozzle cleaning cycle. The mechanism also includes an actuating structure operable to selectively move the cap between an engaged position to press against the printhead and a disengaged position spaced away from the printhead. The actuating structure frictionally engages a drive member so that it can slip against the drive member when the cap reaches the engaged or disengaged positions.
1. A printer comprising:
at least one pagewidth inkjet printhead;
a print media transport mechanism for transporting a print media past said printhead;
a capping mechanism for covering an array of nozzles on the inkjet printhead, the capping mechanism comprising:
a printhead cap;
an actuating structure for selectively moving the cap between an engaged position covering the nozzle array, and a disengaged position spaced from the nozzle array, the actuating structure being connected to the print media transport mechanism;
wherein the actuating structure is operatively connected to the print media transport mechanism such that activation of the print media transport mechanism causes the actuating structure to drive the cap from the engaged position to the disengaged position.
2. A printer according to claim 1 wherein the print media transport mechanism comprises a drive wheel and the actuating structure comprises a slip member to engage with the drive wheel, said engagement extending through at least part of a revolution of the drive wheel, such that rotation of said drive wheel in a first direction causes movement of said cap from said engaged position to said disengaged position, and that rotation of said drive wheel in a second direction causes movement of said cap from said disengaged position to said engaged position.
3. A printer according to claim 1 wherein cap has one or more capping moldings provided to ensure that all nozzles in the array can be capped.
4. A printer according to claim 3 wherein the capping molding has a capping plate which holds an elastomeric seal and sponge, and wherein when the printhead is not in use, the actuating structure is operated to move the capping molding to the engaged position where it is held against the face of the printhead where the elastomeric seal conforms to the face of the printhead and creates an airtight seal around the printhead.
5. A printer according to claim 4 wherein the capping mechanism further comprises a resilient member to assist in holding the capping plate in place against the face of the printhead assembly.
6. A printer according to claim 3 wherein the capping moulding is operatively connected to a rotatable rod, the capping moulding being spaced laterally from the rotatable rod, wherein rotation of the rod about its axis will cause movement of the capping moulding between the engaged and disengaged positions.
7. A printer according to claim 6 wherein the rotatable rod engages with a drive wheel of the printer.