# US 10,369,781 B2 · Mobile printers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,369,781 B2 - Document ID: US10369781B2 - Status: Granted - Kind: B2 - Application number: 15/535,851 - Filed: 2015-01-08 - Published: 2017-11-23 - Granted: 2019-08-06 - Earliest claimed: 2015-01-08 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: John T Brassil; Andy Liao; Vijay Nayak - Web page: https://patentgrep.com/patent/US10369781B2 ## CPC - B41J 2/04508: {aiming at correcting other parameters} - B41J 2/04586: {controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type} - B41J 2/2135: {Alignment of dots} - B41J 2/2142: {Detection of malfunctioning nozzles (generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045, B41J2/05; jet deflection sensors B41J2/125; for cleaning purposes B41J2/16579)} - B41J 3/36: for portability {, i.e. hand-held printers or laptop printers (B41J3/4075 takes precedence)} - B41J 29/023: {with reduced dimensions} - B41J 2/04573: {Timing; Delays} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A mobile printer includes an ultrasound sensor to sense a set of ultrasonically-sensed positional data points of a print nozzle of the printer, at least one optical sensor to sense a set of optically-sensed positional data points of the print nozzle, and a processor. The processor is to apply a correction function on the set of ultrasonically-sensed positional data points and on the set of optically-sensed positional data points to provide a set of corrected positional data points of the print nozzle and is to cause the print nozzle to deposit according to a print request and according to the set of corrected positional data points. ## Claims ### Claim 1 A mobile printer, comprising: an ultrasound sensor to sense a set of ultrasonically-sensed positional data points of a print nozzle of the printer as the mobile printer is moved a direction across a printing surface; an optical sensor to sense a set of optically-sensed positional data points of the print nozzle of the printer when the mobile printer is moved the direction across the printing surface; a motion sensor; and a processor to: apply a correction function on the set of ultrasonically-sensed positional data points and on the set of optically-sensed positional data points to provide a set of corrected positional data points of the print nozzle of the printer; cause the print nozzle to deposit ink according to a print request according to the set of corrected positional data points and information received from the motion sensor corresponding to a change in a location of the printer; identify information from the motion sensor about a reversal of the direction across the printing surface; compensate for a first time lag caused by the reversal of the direction based on a position and a speed of the printer included in the identified information about the reversal of the direction; and supplement the set of ultrasonically-sensed positional data points with the identified information about the reversal of the direction in response to receiving a notification from the motion sensor about the reversal of the direction, wherein the notification prevents printing errors by increasing an accuracy of the set of corrected positional data points. ### Claim 2 (depends on 1) The printer of claim 1, wherein the motion sensor is to sense rapid motion of the printer. ### Claim 3 (depends on 1) The printer of claim 1, wherein the optical sensor is to sense rotation of the printer. ### Claim 4 (depends on 1) The printer of claim 1, wherein the correction function provides the set of corrected positional data points by applying a calibration function on the set of ultrasonically-sensed positional data points and on the set of optically-sensed positional data points. ### Claim 5 (depends on 1) The printer of claim 1, wherein the processor is to determine a second time lag between the print request and the depositing of the ink and to compensate for the second time lag by applying an extrapolation function. ### Claim 6 (depends on 1) The printer of claim 1, wherein the processor is to determine an offset between the print nozzle and the optical sensor, and wherein the processor is to apply the correction function according to the offset. ### Claim 7 (depends on 1) The printer of claim 1, wherein the set of corrected positional data points has an accuracy of up to 1 mil. ### Claim 8 (depends on 1) The printer of claim 1, wherein the processor is to further apply the correction function based on the information corresponding to the change in the location of the printer. ### Claim 9 A mobile printer, comprising: an ultrasound sensor to sense a set of ultrasonically-sensed positional data points of a print nozzle as the mobile printer is moved a direction across a printing surface; a plurality of optical sensors to sense a set of optically-sensed positional data points of the print nozzle when the mobile printer is moved the direction across the printing surface; a motion sensor; and a processor to: receive a print request from a computing device; determine an offset between the print nozzle and the plurality of optical sensors; apply a calibration function, according to the offset, on the set of ultrasonically-sensed positional data points, the set of optically-sensed positional data points, and information received from the motion sensor corresponding to a motion of the printer to provide a set of corrected positional data points of the print nozzle of the printer; cause the print nozzle to deposit ink according to a print request and to the set of corrected positional data points; identify information from the motion sensor about a reversal of the direction across the printing surface; compensate for a first time lag caused by the reversal of the direction based on a position and a speed of the printer included in the identified information about the reversal of the direction; and supplement the set of ultrasonically-sensed positional data points with the identified information about the reversal of the direction in response to receiving a notification from the motion sensor about the reversal of the direction, wherein the notification prevents printing errors by increasing an accuracy of the set of corrected positional data points. ### Claim 10 (depends on 9) The printer of claim 9, wherein the motion sensor is to detect rapid motion of the print nozzle. ### Claim 11 (depends on 9) The printer of claim 9, wherein the plurality of optical sensors is to measure rotation of the print nozzle. ### Claim 12 (depends on 9) The printer of claim 9, wherein the processor is to determine a second time lag between the print request and the depositing of the ink and to compensate for the second time lag by applying an extrapolation function. ### Claim 13 (depends on 9) The printer of claim 9, wherein the set of corrected positional data points has an accuracy of up to 1 mil. ### Claim 14 (depends on 9) The printer of claim 9, wherein the processor is to further receive information corresponding to a change in a location of the printer from the motion sensor. ### Claim 15 (depends on 14) The printer of claim 14, wherein the processor is to further cause the print nozzle to deposit ink according to the information corresponding to the change in the location of the printer. ### Claim 16 A method of printing, comprising: receiving a print request; collecting a set of ultrasonically-sensed positional data points of a print nozzle as the mobile printer is moved a direction across a printing surface; collecting a set of optically-sensed positional data points of the print nozzle when the mobile printer is moved the direction across the printing surface; collecting information corresponding to a motion of the printer from a motion sensor; applying a correction function on the set of ultrasonically-sensed positional data points, the set of optically-sensed positional data points, and the information corresponding to the motion of the printer to provide a set of corrected positional data points of the print nozzle; depositing ink according to the print request and the set of corrected positional data points; identifying information from the motion sensor about a reversal of the direction across the printing surface; compensating for a first time lag caused by the reversal of the direction based on a position and a speed of the printer included in the identified information about the reversal of the direction; and supplementing the set of ultrasonically-sensed positional data points with the identified information about the reversal of the direction in response to receiving a notification from the motion sensor about the reversal of the direction, wherein the notification prevents printing errors by increasing an accuracy of the set of corrected positional data points. ### Claim 17 (depends on 16) The method of claim 16, comprising: determining a second time lag between a print request and the depositing of the ink; and applying an extrapolation function to compensate for the second time lag. ### Claim 18 (depends on 16) The method of claim 16, wherein the correction function applies a calibration function on the set of ultrasonically-sensed positional data points and on the set of optically-sensed positional data points. ### Claim 19 (depends on 16) The method of claim 16, wherein the motion of the printer corresponds to a sudden, undesirable change in a location of the printer. ### Claim 20 (depends on 16) The method of claim 16, wherein the set of optically-sensed positional data points includes data points corresponding to a rotation of the print nozzle.