Non mechanical optical beam steering mechanism for laser printers

• US 10,462,323 B1
• Filed: 06/28/2018
• Issued: 10/29/2019
• Est. Priority Date: 06/22/2018
• Status: Active Grant

• Current Assignee: Capital One Services LLC (Capital One Financial Corporation)
• Original Assignee: Capital One Services LLC (Capital One Financial Corporation)
• Inventors: Wurmfeld, David
• Primary Examiner(s): Zimmermann, John
• Application Number:
  US16/021,091
• Time in Patent Office: 488 Days
• CPC Class Codes: B41J 2/442 using lasers
• CPC Class Codes: B41J 2/445 using liquid crystals
• CPC Class Codes: B41J 2/47 using the combination of scanning and modulation of light
• CPC Class Codes: B41J 2/471 using dot sequential main scanning by means of a light deflector, e.g. a rotating polygonal mirror
• CPC Class Codes: B41J 2202/50 Embodiments of processes related to optical heads
• CPC Class Codes: G02B 2006/0098 for scanning
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 26/0875 by means of one or more refracting elements
• CPC Class Codes: G02B 26/0891 forming an optical wedge
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/103 having movable or deformable optical fibres, light guides or waveguides as scanning elements light guides per se G02B6/00
• CPC Class Codes: G02B 26/108 having one or more prisms as scanning elements
• CPC Class Codes: G02B 27/0977 Reflective elements
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02F 1/295 Analog deflection from or in an optical waveguide structure]
• CPC Class Codes: G02F 2203/24 beam steering
• CPC Class Codes: H04N 1/0282 Using a single or a few point light sources, e.g. a laser diode
• CPC Class Codes: H04N 1/23 Reproducing arrangements
• CPC Class Codes: H04N 1/295 Circuits or arrangements for the control thereof, e.g. using a programmed control device, according to a measured quantity

Abstract

A laser printing system includes a laser configured to produce a beam of light modulated according to image data input to the laser printing system, a photoreceptor drum including a photoconductive layer disposed along an outer peripheral surface of the photoreceptor drum, and a non-mechanical beam steerer configured for receiving the modulated light beam from the laser and steering the light beam in a scanning motion back and forth across the photoconductive layer of the photoreceptor drum. The laser printing system also includes a printer controller configured to structure the image data input to the laser printing system, and control an amount of electrical current flowing through portions of the non-mechanical beam steerer to change an effective index of refraction of the non-mechanical beam steerer and steer the modulated light beam in the scanning motion.

Claims

1. A method of laser printing, comprising:

receiving image data from a computing device at a laser printer controller;

activating a laser using the printer controller in accordance with the received image data to produce a modulated laser light beam;

receiving the laser light beam into an array of waveguide cores of an optical waveguide having a controllable index of refraction, wherein an insulating layer is provided adjacent the array of waveguide cores with one or more openings through the insulating layer configured to expose different amounts of different waveguide cores of the array of waveguide cores to portions of a liquid crystal cladding layer;

controlling a voltage applied to the liquid crystal cladding layer to separately tune all of the waveguide cores and produce a different phase shifting effect for each different waveguide core by selectively changing an effective index of refraction of the liquid crystal cladding layer, thereby causing the laser light beam to exit the waveguide in a scanning motion; and

directing the scanning laser light beam across a photoconductive layer on a rotating photoreceptor drum in a direction parallel to a central axis of the drum.

2. The method of claim 1, further comprising:

organizing the image data, using the printer controller, into pages of information to be printed on recording medium by setting text margins, and arranging words and graphics;

processing the image data using a raster image processor by taking at least a portion of the page data and breaking the data down into an array of dots;

feeding the dots one horizontal line at a time to the laser; and

activating the laser to output a pulsed light beam to the optical waveguide, with one pulse of light from the laser for every dot to be printed.

3. The method of claim 1, wherein controlling the voltage includes applying the voltage to electrodes on opposite sides of the liquid crystal cladding layer, the liquid crystal cladding layer having a liquid crystal material disposed therewithin.

4. The method of claim 3, wherein controlling the voltage comprises applying the voltage to an Indium-Tin-Oxide electrode formed along a surface of the liquid crystal cladding layer, and along an electrode formed in a substrate, the substrate supporting the array of waveguide cores and the liquid crystal cladding layer.

5. The method of claim 1, further comprising:

activating a pre-charger, using the printer controller, to impart a positive static electrical charge uniformly across the photoconductive layer of the drum before directing the scanning laser light beam across the photoconductive layer.

6. The method of claim 5, wherein directing the laser light beam includes activating the laser, using the printer controller, to produce pulses of light to discharge selected portions of the positively charged photoconductive layer corresponding to the image data.

7. The method of claim 1, further comprising:

focusing the modulated light beam with a collimator lens before receiving the modulated laser light beam into the waveguide cores; and

focusing the laser light beam exiting the optical waveguide to compensate for distortions of the image data resulting from different distances between the waveguide and points along the photoconductive layer on the drum.

8. The method of claim 1, further comprising:

activating a pre-charger, using the printer controller, to impart a positive static electrical charge uniformly across the photoconductive surface before directing the scanning laser light beam across the photoconductive layer;

activating the laser, using the printer controller, to produce pulses of light to discharge selected portions of the positively charged photoconductive surface corresponding to the image data;

developing a latent image corresponding to the image data on the photoconductive surface by introducing positively charged toner particles to the photoconductive surface; and

passing a recording medium having a strong negative static electrical charge in proximity to the photoconductive surface such that the positively charged toner particles are transferred to the recording medium from the photoconductive surface to form an image corresponding to the image data.

9. A method for scanning a modulated laser light beam output by a laser of a laser printer across a photoconductive surface of a photoreceptor drum, the method comprising:

receiving the modulated laser light beam into an array of waveguide cores of an optical waveguide with a controllable index of refraction, wherein an insulating layer is provided adjacent the array of waveguide cores with one or more openings through the insulating layer configured to expose different amounts of different waveguide cores of the array of waveguide cores to portions of a liquid crystal cladding layer; and

controlling a voltage applied to the liquid crystal cladding layer to separately tune all of the waveguide cores and produce a different phase shifting effect for each different waveguide core by selectively changing an effective index of refraction for the laser light beam propagating through the array of waveguide cores, thereby causing the laser light beam to exit the waveguide in a scanning motion.

10. The method according to claim 9, wherein controlling the voltage applied to the liquid crystal cladding layer includes applying the voltage to electrodes on opposite sides of the liquid crystal cladding layer, the liquid crystal cladding layer having a liquid crystal material disposed therewithin.

11. The method according to claim 10, wherein controlling the voltage comprises applying the voltage to an Indium-Tin-Oxide electrode formed along a surface of the liquid crystal cladding layer, and along an electrode formed in a substrate supporting the array of waveguide cores and the liquid crystal cladding layer.

12. The method according to claim 9, wherein applying the voltage to the liquid crystal cladding layer comprises controlling, by a printer controller, variations in individual pixels produced on the photoconductive layer.

13. The method according to claim 9, wherein controlling the voltage comprises controlling, by a printer controller, variations in line retrace time or the time it takes the laser light beam to scan from one side of a page to the opposite side of the page.

14. The method according to claim 9, wherein the voltage applied to the optical waveguide is controlled by a printer controller to control variations in page retrace time or the time it takes to reset information for a successive page of information being printed.

15. The method according to claim 9, further comprising directing the modulated laser light beam output by the laser through a collimating lens before receiving the modulated laser light beam into the array of waveguide cores.

16. The method according to claim 9, further comprising directing the laser light beam exiting the waveguide in a scanning motion through a focusing lens before contacting the photoconductive surface of the photoreceptor drum.

17. A method of operating a laser printer, comprising:

receiving a modulated laser light beam from a laser diode into an array of waveguide cores of an optical waveguide having a controllable index of refraction, wherein an insulating layer is provided adjacent the array of waveguide cores with one or more openings through the insulating layer configured to expose different amounts of different waveguide cores of the array of waveguide cores to portions of a liquid crystal cladding layer;

controlling a voltage applied to the liquid crystal cladding layer, using a printer controller, to separately tune all of the waveguide cores and produce a different phase shifting effect for each different waveguide core by selectively changing an effective index of refraction of the array of waveguide cores, thereby causing the laser light beam to exit the waveguide in a scanning motion; and

directing the scanning laser light beam across a photoconductive layer on a rotating photoreceptor drum.

18. The method according to claim 17, wherein controlling the voltage includes applying the voltage across a liquid crystal material contained within the liquid crystal cladding layer disposed along at least one of opposite sides of the array of waveguide cores.

19. The method of claim 18, wherein controlling the voltage comprises applying the voltage to an Indium-Tin-Oxide electrode formed along a surface of the liquid crystal cladding layer, and along an electrode formed in a silicon substrate, the substrate supporting the array of waveguide cores and the liquid crystal cladding layer.

20. The method of claim 17, further comprising:

activating a pre-charger, using the printer controller, to impart a positive static electrical charge uniformly across the photoconductive layer before directing the scanning laser light beam across the photoconductive layer;

activating the laser, using the printer controller, to produce pulses of light to discharge selected portions of the positively charged photoconductive layer corresponding to image data received by the printer controller;

developing a latent image corresponding to the image data on the photoconductive layer by introducing positively charged toner particles to the photoconductive layer; and

passing a recording medium having a negative static electrical charge in proximity to the photoconductive layer such that the positively charged toner particles are transferred to the recording medium from the photoconductive layer to form an image corresponding to the image data.