Measuring and testing – Sheet – woven fabric or fiber
Reexamination Certificate
2000-10-24
2001-09-18
Chapman, John E. (Department: 2856)
Measuring and testing
Sheet, woven fabric or fiber
C073S597000, C347S106000, C271S009060
Reexamination Certificate
active
06289730
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to paper handling systems, and more particularly to a technique for detecting the size of paper or other print media using ultrasound detection.
BACKGROUND OF THE INVENTION
Most printers such as ink-jet printers employ some type of sheet handling system for picking a sheet of print media such as paper from an input tray, advancing the picked sheet to a print area for printing operations, and delivering the sheet after printing to an exit location such as an output tray. The printers typically support printing on several media sizes, and may have more than one input tray or source. It therefore is useful in some applications to employ a media size detection system to detect the size of the paper or other print media that is being handled by the sheet handling device.
Some printers have used multiple reflective optical detectors located in the paper path to detect the size of the paper. This is expensive, particularly for more than two different paper sizes. Accordingly, it would be advantageous to provide a paper size detection technique which did not rely on optical detectors.
SUMMARY OF THE INVENTION
A detection system is disclosed for detecting the size of a print medium, and includes an apparatus for defining a hollow chamber. A drive signal generator is provided for generating pulses of electrical drive signals; in an exemplary embodiment, the drive signals are in an ultrasonic frequency range. The system further includes a transducer apparatus responsive to the electrical drive pulses for launching pulses of energy into the tube and responsive to echoes of the pulses to convert echo pulse energy into electrical detected signals. A flag positioning apparatus selectively positions a blocking flag within the tube at a location spaced from the transducer which is indicative of a print medium size. A controller is responsive to the electrical detected signals to determine a print medium size.
The apparatus for defining a hollow chamber can be a hollow tube. The flag positioning apparatus can provide a single flag movable along a longitudinal extent of the chamber, or a set of flags spaced along the longitudinal extent, one or more of which are selectably deflected by the print medium.
In accordance with another aspect of the invention, a method is disclosed for detecting the size of a print medium, comprising the steps of:
positioning an apparatus defining a hollow chamber adjacent the print medium;
positioning a blocking flag within the chamber at a location corresponding to a print medium size;
launching one or more pulses of ultrasonic energy into the chamber;
detecting the position of the blocking flag in the chamber by determining the time between the launching of the one or more pulses and the receipt of corresponding echoes of said one or more pulses at a transducer apparatus; and
determining the print medium size in dependence on the detected position of said blocking flag.
REFERENCES:
patent: 4108427 (1978-08-01), Komori et al.
patent: 5606430 (1997-02-01), Morikawa et al.
patent: 5629529 (1997-05-01), Motoyama
patent: 6039481 (2000-03-01), Ham
Chapman John E.
Hewlett--Packard Company
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