Printing – Processes – Position or alignment
Reexamination Certificate
1999-10-29
2001-10-09
Eickholt, Eugene (Department: 2854)
Printing
Processes
Position or alignment
C347S019000, C101SDIG029
Reexamination Certificate
active
06298783
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an alignment device for mounting an alignable part, such as a thermal printhead, on a support frame that can be independently guided to position the working component in a mounting housing structure. The alignment device provides for precise alignment of a line on the working part, such as a print line of thermal print elements, relative to close fitting guides on the support frame so when put into use the working component is guided into its proper location. Proper alignment of thermal printheads, in particular, as well as other working components that have a narrow line of contact with another element is critical to satisfactory operation.
Conventional thermal printheads are held by a variety of different types of supports. In particular since printheads must be moved for servicing ribbons, pivoting frames are used for moving the printheads between a working and an open position. The printhead is pivoted 90° away from the platen used with the printhead. Obtaining accurate alignment of the printhead when moved back into working position relative to the platen has been a problem.
Also, in the copending application cross referenced above, a structure for supporting the printhead so that it will remain oriented in space as it is moved to open position to keep the print line facing away from operators provides for pivotal mounting of the support for the printhead. The support or frame is guided directly onto the shaft of a platen roller. If the print line is oriented properly with the guides carried on the support mounting frame, the print line will be properly oriented relative to the platen during use.
SUMMARY OF THE INVENTION
The present invention relates to a mounting frame or support and an alignment device that aligns a line on a part such as the print line on a thermal printhead, that needs to be positively positioned relative to another member (a platen) when in a working position. Thermal printhead having a line of heated resistive elements for printing from a ribbon is formed with a separate housing, and has an edge along which the print line to be properly positioned is defined. In the case of the printhead, the print line has to be positively positioned relative to a rotating platen roller, both as to radial angle, and for parallel positioning relative to the axis of rotation of the roller.
A mounting frame that has reference supports provides guided support for the printhead. The printhead is adjustably mounted in the mounting frame and is fixed in place after aligning it properly. The mounting frame has a pair of side members joined together with a cross wall that spans the printhead, and the side members are provided with two datum locator or reference positions for locating the mounting frame on supports on a printer. The mounting frame is positively guided as shown relative to side plates of a printer housing, for one datum or reference location, and also is positively guided onto the platen roller shaft that extends out from the opposite ends of the platen roller so that a reliable, proper position is achieved when the guides are in place.
The alignment of the print line is inspected and checked with a video camera that has a screen display which can be provided with reference lines so that the image of the print line, displayed by the camera, with the mounting frame and printhead on a precisely formed fixture, can be observed as to whether or not it is within the limits. The printhead is then adjusted relative to the mounting frame as it remains supported on the fixtures, to insure that the printhead is aligned within set limits. Screw adjustments are used as shown for precisely adjusting the printhead relative to its support frame, and then fixing the printhead in position on the mounting frame.
The mounting frame is positively guided on the platen supports, and also on printer housing guide blocks to position the side members of the printhead mounting frame and thereby hold the printhead at a proper angle and precisely parallel to the axis of the platen, with which the printhead operates.
Other working components or parts can be aligned as disclosed to orient a transverse line on the working component appropriately with a mounting frame that is guided into position.
REFERENCES:
patent: 5500801 (1996-03-01), Löffler
patent: 5676058 (1997-10-01), Ireton
patent: 5850789 (1998-12-01), Rudolf et al.
patent: 5964032 (1999-10-01), Orikasa et al.
patent: 6003980 (1999-12-01), Sheinman et al.
patent: 6055908 (2000-05-01), Van Der Horst
patent: 6085658 (2000-07-01), Goldstein
Brand Steven J.
Meier James R.
O'Mera Neil E.
Eickholt Eugene
Fargo Electronics Inc.
Westman Champlin & Kelly P.A.
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