Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-03-09
2003-03-18
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S029000
Reexamination Certificate
active
06533388
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a service station in an inkjet printer, and to an inkjet printer incorporating such a service station.
BACKGROUND OF THE INVENTION
The service station of an inkjet printer includes an apparatus for wiping and capping the printheads carried by an inkjet carriage. The wipers are arranged to wipe the residual ink from the printheads after completion of printing. The wiping and capping operations of the service station prevent the printheads from becoming blocked and thereby extend their lives.
U.S. Pat. No. 5,627,574 describes a maintenance device in an inkjet printing apparatus. The maintenance device includes a fixed wiper which is used to wipe residual ink from the printhead. However, as the wiper is fixed it is always in contact with the printhead as the printing carriage enters and leaves the maintenance device. Accordingly, the arrangement of U.S. Pat. No. 5,627,574 is such that the wiper may cause cross contamination of ink in a multiple inkjet printhead system. This is because the wiper would wipe over both printheads and therefore any residual ink from one printhead would be deposited on the other printhead. This greatly impacts on the performance of the inkjet printer. The present invention seeks to address this problem.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided a service station for an inkjet printer, said service station including at least one cap for capping a printhead which is mounted on an inkjet carriage of said inkjet printer, and at least one wiper arranged to wipe the printhead carried by the inkjet carriage and wherein the wiper is arranged to move towards and away from said printhead in response to movement of the inkjet carriage.
Preferably, said service station includes first and second caps for capping respective first and second printheads. The service station preferably includes first and second wipers arranged to wipe said respective first and second printheads.
In a preferred form of the invention, the service station includes a main frame arranged to be mounted to a chassis of the inkjet printer, a cap frame on which said first and second caps are mounted and a wiper frame on which said first and second wipers are mounted. The cap frame and wiper frame are connected to said main frame in a manner whereby movement of the cap frame results in the movement of said wiper frame to an in-use position in which said first and second wipers can wipe their respective printheads. The wiper frame is preferably arranged to move between a lower or out of use position to an upper or in-use position.
In a preferred form, the cap frame can move both horizontally and vertically relative to said main frame to achieve capping of said first and second printheads. Vertical movement of said cap frame also preferably results in a vertical movement of said wiper frame to said in-use position. Vertical movement of said wiper frame causes said first and second wipers to move from a lower position in which they do not contact their respective printheads to said upper position in which the printheads are wiped by their respective wipers.
The service station preferably includes means to lock the wiper frame in the upper position. The lock means preferably includes a spring biased wiper hook which is arranged to be hingedly connected to the wiper frame. The bias for the wiper hook is preferably provided by a spring connection between a portion of the wiper hook and a portion of the wiper frame.
Release means is preferably provided to release the locking means so that the wiper frame can move from the upper position to the lower position. The release means is preferably activated by the inkjet carriage contacting a release member mounted on the main frame. The release member is preferably an activation arm pivotally mounted on the main frame. The activation arm preferably has a free end arranged to contact said wiper hook when the activation arm is caused to pivot downwardly. Contact of the free end of the activation arm on the wiper hook causes the spring biased wiper hook to disengage from an engagement member on the main frame and to move under the action of the spring bias to the lower position.
A biasing means, preferably in the form of a leaf spring, is located between the main frame and the wiper frame. The leaf spring serving to bias the wiper frame away from the main frame and into the lower position.
Preferably, a blotter is arranged to be mounted on the cap frame so that any ink wiped from the printheads by the wipers is collected by the blotter.
The caps are preferably located on a cap mount which snap fits to the cap frame.
The wipers preferably snap fit onto respective wiper mounts which are integrally formed with the wiper frame.
The cap frame is preferably connected to the chassis or the main frame by a tension spring. The tension spring serving to return the cap frame from a position in which the caps cover their respective printheads to a clear position in which the caps do not cover their respective printheads.
The service station is preferably arranged to be used in an inkjet printer having an inkjet carriage mounted on a shaft. The service station is mounted on a chassis of the printer such that the inkjet carriage can be driven along the shaft and over the service station so as to enable the inkjet carriage to contact a portion of the cap frame. Contact between the inkjet carriage and the portion of the cap frame causes the cap frame to move with the inkjet carriage to a home position. The cap frame is mounted on the main frame in such a manner that contact between the cap frame and the inkjet carriage cause both a substantially horizontal and a substantially vertical change in the positioning of the cap frame relative to the main frame. To this end, the cap frame preferably includes at least one pin extending therefrom which is arranged to be located in a ramp formed in the main frame. Movement of the cap frame due to contact by the inkjet carriage causes the cap frame to move along and up the ramp thereby changing the vertical positioning of the cap frame relative to the chassis as well as its horizontal positioning.
Preferably, the cap frame has two pairs of opposed pins extending therefrom. The pins being arranged to extend from the sides of the cap frame and to move in respective ramps formed in the main frame.
The wiper frame preferably includes at least one pin extending therefrom and arranged to be located within a groove formed in the main frame. The wiper frame pin is preferably arranged to move upwardly in the groove in the main frame as a result of the end of the pin engaging in an aperture formed in the cap frame. Accordingly, said substantially vertical movement of said cap frame during movement of the inkjet carriage to the home position causes said pin of said wiper frame to move upwardly within the groove formed in the main frame.
Preferably, the wiper frame includes two pairs of opposed pins mounted on the sides of the wiper frame, each pin being arranged to be received in a respective groove formed in the main frame.
REFERENCES:
patent: 5585826 (1996-12-01), Schroeder et al.
patent: 5627574 (1997-05-01), Fahy
patent: 5821955 (1998-10-01), Waschhauser
patent: 5847728 (1998-12-01), Lee
patent: 5966146 (1999-10-01), Lee
patent: 0604067 (1994-06-01), None
patent: 0604068 (1994-06-01), None
patent: 0653306 (1995-05-01), None
patent: 0896881 (1999-02-01), None
Huang Mu Hua
Koh Joo Beng
Lee Yang Teh
Liew Kan Min
Toh Cher Lek
Hewlett--Packard Company
Pham Hai
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