# US 7,411,603 B2 · Light guide > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,411,603 B2 - Document ID: US7411603B2 - Status: Granted - Kind: B2 - Application number: 11/092,321 - Filed: 2005-03-29 - Published: 2006-10-12 - Granted: 2008-08-12 - Earliest claimed: 2005-03-29 - Assignees: Hewlett-Packard Development Company, L.P. - Inventors: David A. Rehmann - Web page: https://patentgrep.com/patent/US7411603B2 ## CPC - B41J 11/008: {Controlling printhead for accurately positioning print image on printing material, e.g. with the intention to control the width of margins} - B41J 11/0095: {Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract In embodiments, light from a light guide is used to generate a signal. ## Claims ### Claim 1 An apparatus comprising: a plurality of independently operable light emitting devices; a light guide positioned to allow media to move between the light guide and the plurality of light emitting devices and configured to guide light from the plurality of light emitting devices; a single light sensing device positioned to receive the light from the plurality of light emitting devices guided by the light guide and to generate a signal indicative of the light, wherein the single light sensing device comprises a single photocell or photoreceptor; and a control unit configured to receive the signal generated by the single light sensing device, wherein the control unit is configured to simultaneously energize the plurality of light emitting devices to detect a presence of a hole in the media, and after detecting the presence of the hole in the media, sequentially energize individual ones of the plurality of light emitting devices to detect a location of the hole in the media. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the plurality of light emitting devices emit light toward a first side of the media, and wherein the light guide receives light transmitted through holes in the media on a second side of the media. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the light guide directs light from a plurality of input locations to a single output location. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the plurality of light emitting devices emit light in the infrared spectrum. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the plurality of light emitting devices emit light in the visible spectrum. ### Claim 6 A method comprising: receiving light passed through a hole in media into a light guide, with the media positioned between a plurality of independently operable light emitting devices and the light guide; directing the light from the plurality of light emitting devices in the light guide to a single light sensing device, wherein the single light sensing device comprises a single photocell or photoreceptor; and generating a signal indicative of the hole in the media using the light reaching the light sensing device, wherein receiving the light passed through the hole in the media includes simultaneously energizing the plurality of light emitting devices to detect a presence of the hole in the media, and after detecting the presence of the hole in the media, sequentially energizing individual ones of the plurality of light emitting devices to detect a location of the hole in the media. ### Claim 7 (depends on 6) The method of claim 6, further comprising advancing the media between the plurality of light emitting devices and the light guide. ### Claim 8 (depends on 7) The method of claim 7, further comprising energizing the plurality of light emitting devices as the media advances between the light emitting devices and the light guide. ### Claim 9 (depends on 6) The method of claim 6, further comprising preventing the formation of an image at the location of the hole in the media. ### Claim 10 (depends on 6) The method of claim 6, further comprising determining if the media is an anticipated media. ### Claim 11 (depends on 10) The method of claim 10, further comprising altering an image forming process if the media is not the anticipated media. ### Claim 12 An image forming system comprising: a hole detection apparatus comprising a plurality of independently operable light emitting devices, a light guide positioned to allow media to move between the light guide and the plurality of light emitting devices and configured to guide light from the plurality of light emitting devices, and a single light sensing device positioned to receive the light from the plurality of light emitting devices guided by the light guide and to generate a signal indicative of the light, wherein the single light sensing device comprises a single photocell or photoreceptor; an imaging unit for forming an image on the media; and a control unit in communication with the hole detection apparatus and the imaging unit, the control unit for receiving the signal generated by the hole detection apparatus and for preventing the formation of the image at a location of a hole in the media, wherein the control unit simultaneously energizes the plurality of light emitting devices to detect a presence of a hole in the media, and after detecting the presence of the hole in the media, sequentially energizes individual ones of the plurality of light emitting devices to detect a location of the hole in the media. ### Claim 13 (depends on 12) The image forming system of claim 12, wherein the light guide comprises a monolithic element having an input location for each of the plurality of light emitting devices, and a single output location. ### Claim 14 (depends on 12) The image forming system of claim 12, wherein the plurality of light emitting devices and the light guide are positioned across a width of the media transverse to a direction of movement of the media. ### Claim 15 A computer-readable storage medium having computer-readable instructions for causing an image forming system to perform a method for de holes in print media in an image forming system, the method comprising: receiving light passed through a hole in media into a light guide, with the media positioned between a plurality of independently operable light emitting devices and the light guide; directing the light from the plurality of light emitting devices in the light guide to a single light sensing device; and generating a signal indicative of the hole in the media using the light reaching the light sensing devices, wherein receiving the light passed through the hole in the media includes simultaneously energizing the plurality of light emitting devices to detect a presence of the hole in the media, and after detecting the presence of the hole in the media, sequentially energizing individual ones of the plurality of light emitting devices to detect a location of the hole in the media. ### Claim 16 (depends on 15) The computer-readable storage medium having computer-readable instructions of claim 15, wherein the method further comprises advancing the media between the plurality of light emitting devices and the light guide. ### Claim 17 (depends on 16) The computer-readable storage medium having computer-readable instructions of claim 16, wherein the method further comprises energizing the plurality of light emitting devices as the media advances between the light emitting devices and the light guide. ### Claim 18 (depends on 15) The computer-readable storage medium having computer-readable instructions of claim 15, wherein the method further comprises altering an image forming process if the media is not an anticipated media.