Obtaining pressure of an operating environment of a bi-directionally scanning electrophotographic device for implementing corrections per pressure
View Patent ↗Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.
1. A method of obtaining ambient pressure from a device having a bi-directionally moving scanning mechanism that operates in the ambient pressure and a controller, comprising:
providing a drive signal to substantially resonate the scanning mechanism of the device;
ascertaining a parameter of the drive signal;
correlating the parameter of the drive signal to pressure to determine the ambient pressure of the device; and
implementing a scan alignment correction based upon the determined ambient pressure without affecting the ambient pressure, the providing being performed by the controller of the device.
2. The method of claim 1 , wherein the providing the drive signal further includes providing a sequence of pulses.
3. The method of claim 2 , wherein the ascertaining the parameter of the drive signal further includes determining a pulse width of one pulse of the sequence of pulses.
4. The method of claim 3 , wherein the correlating the parameter further includes determining a difference between the pulse width and a nominal pulse width.
5. The method of claim 1 , further including modeling pressure relative to a nominal parameter of the drive signal before use of the device.
6. The method of claim 1 , wherein the ambient pressure is determined without receiving a signal from a pressure sensor.
7. The method of claim 1 , further comprising receiving image data input for printing by the device, wherein implementing the scan alignment correction comprises altering the image data input.
8. The method of claim 1 , wherein implementing the scan alignment correction comprises altering pulse widths of the drive signal.
9. The method of claim 1 , wherein one or more of the ascertaining, the correlating and the implementing being performed by the controller of the device.
10. A method of operating a device having a bi-directionally moving scanning mechanism and a controller, comprising:
providing a drive signal to substantially resonate the scanning mechanism of the device;
ascertaining a parameter of the drive signal;
determining ambient pressure of the device based upon the ascertained parameter; and
implementing a scan alignment correction based on the determined ambient pressure without affecting ambient pressure, the drive signal being provided by the controller of the device.
11. The method of claim 10 , wherein the parameter is at least one pulse width of the drive signal.
12. The method of claim 11 , wherein the ascertaining comprises comparing the at least one pulse width of the drive signal to at least one predetermined pulse width.
13. The method of claim 10 , further comprising receiving image data input for printing by the device, wherein implementing the scan alignment correction comprises altering the image data input.
14. The method of claim 10 , wherein implementing the scan alignment correction comprises altering the drive signal.
15. The method of claim 10 , wherein determining the ambient pressure comprises correlating the parameter of the drive signal to pressure.
16. An apparatus, comprising:
a bi-directionally moving scanning mechanism for creating a plurality of scan lines in opposite directions to create a latent image; and
a controller for controlling movement of the scanning mechanism with a drive signal, the controller executing machine readable instructions for providing a drive signal to substantially resonate the scanning mechanism, ascertaining a parameter of the drive signal, determining ambient pressure of the apparatus based upon the ascertained parameter, and implementing a scan alignment correction based on the determined ambient pressure without adjusting the ambient pressure.
17. The apparatus of claim 16 , wherein the parameter is at least one pulse width of the drive signal.
18. The apparatus of claim 17 , wherein the determining comprises comparing the at least one pulse width of the drive signal to at least one predetermined pulse width.
19. The apparatus of claim 16 , wherein the apparatus determines ambient pressure without a pressure sensor.
20. The apparatus of claim 16 , wherein the controller implementing the scan alignment correction comprises altering an image data input to be printed.
21. The apparatus of claim 16 , wherein the controller implementing the scan alignment correction comprises altering the drive signal.