Encoder strip damage detector
AssigneeHewlett-Packard Development Company, L.P.
InventorsSamuel K. Swenson, Ryan Christensen
Life of this patent
Estimating the term…
Abstract
A method and apparatus for detecting a damaged encoder strip are described. An encoder strip is scanned in two separate operations at two separate times, a first operation and a second operation. The number of markings sensed in each separate operation is counted. A circuit compares the count of markings in each separate operation. If the count differs between the two operations, the circuit determines that the encoder strip is damaged, and the circuit develops a signal indicating this damage. In an embodiment, the first operation is performed during a calibration, and the second operation is performed during a power-on, or upon operator command.
Claims43
A device with a movable mechanism, comprising:
- an encoder strip having markings to indicate a position of the mechanism;
- an encoder strip reader to detect the markings;
- and
- an encoder strip damage detector configured to determine whether the encoder strip is damaged based on changes in a count of the markings detected by the encoder strip reader over time.
An encoder system comprising:
- an encoder strip having markings to indicate a position of a moveable mechanism;
- an encoder strip sensor having a sensor output that is responsive to sense the encoder strip markings;
- and
- a control circuit responsive to the encoder strip sensor to determine whether the encoder strip is damaged based on a difference in the sensor output in at least two separate sensing operations performed over the same portion of the encoder strip.
A method of operating a printing device, the method comprising:
- sensing and counting a number of encoder strip markings on at least a portion of an encoder strip in a first operation and in a subsequent second operation;
- and
- comparing a count of the number of markings in the first operation with a count of the number of markings in the second operation to determine whether the encoder strip is damaged.
In a printing device of a type having a mechanism configured to move along a scan-axis, an encoder strip, and an encoder strip sensor circuit to generate an indication of a sensed markings on the encoder strip, the printing device comprising:
- a computer readable media having stored thereon a plurality of instructions that, when executed by a processor of the device, cause the processor to perform acts comprising reading from the encoder strip sensor circuit a quantity of markings indicated in a first sensing operation, reading from the encoder strip sensor circuit a quantity of markings indicated in a second sensing operation, and comparing the quantity of markings indicated in the first sensing operation and in the second sensing operation.
A printing device comprising:
- means for sensing markings on an encoder strip over time, and
- means for detecting anomalies in the sensed markings.
Dependencies are inferred from the claim text.