# US 6,004,050 A · Carriage scanning system with carriage isolated from high frequency vibrations in drive belt > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,004,050 A - Document ID: US6004050A - Status: Granted - Kind: A - Application number: 08/995,773 - Filed: 1997-12-22 - Granted: 1999-12-21 - Earliest claimed: 1997-12-22 - Assignees: Hewlett-Packard Company - Inventors: David Rehman; Tod S. Heiles; Geoff Wotton; John Sturman - Web page: https://patentgrep.com/patent/US6004050A ## CPC - H04N 1/128: {using a scanning head arranged for linear reciprocating motion} - B41J 19/005: {Cable or belt constructions for driving print, type or paper-carriages, e.g. attachment, tensioning means} - H04N 1/053: in main scanning direction, e.g. synchronisation of line start or picture elements in a line - H04N 1/12: using the sheet-feed movement {or the medium-advance or the drum-rotation movement} as the slow scanning component, {e.g. arrangements for the main-scanning}({sheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; } using multi-element arrays H04N1/19) - H04N 1/1911: {Simultaneously or substantially simultaneously scanning picture elements on more than one main scanning line, e.g. scanning in swaths} - H04N 2201/02443: using adhesive - H04N 2201/0428: Stabilising the scanning parts; Preventing vibrations - H04N 2201/0471: using dedicated detectors - H04N 2201/04727: on a linear encoder - H04N 2201/04734: Detecting at frequent intervals, e.g. once per line for sub-scan control - H04N 2201/04767: by controlling the timing of the signals, e.g. by controlling the frequency o phase of the pixel clock - H04N 2201/04798: Varying the main-scan control during the main-scan, e.g. facet tracking - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A carriage drive system includes a carriage driven along a carriage path under a force generated by a drive motor. The driving force is coupled to the carriage by a drive belt. High frequency vibrations occurring in the drive belt are isolated from the carriage to improve print quality or scanning accuracy. Vibrations are introduced to the drive belt by the drive motor, the connection between the drive motor and the drive belt or from another source. High frequency decoupling is achieved using a spring connection which serves as a low pass filter of vibration frequencies. In addition, a linear encoder is included on the carriage for detecting carriage position. Such linear encoder samples carriage position at a rate fast enough to enable compensation for low frequency carriage vibrations. ## Claims ### Claim 1 A carriage scanning system, comprising: a carriage which moves along a carriage path; a spring mounted to the carriage; a drive motor which generates a drive force; a drive belt coupled to the drive motor and the spring, the spring serving as a link which elastically couples the drive belt to the carriage, the drive belt coupling the drive force to the carriage through the spring to cause the carriage to move along the carriage path; and means for isolating the carriage from vibrations occurring within the drive belt, the isolating means comprising the spring. ### Claim 2 (depends on 1) The system of claim 1, wherein the spring is a low pass filter of mechanical vibrations which filters out frequencies greater than a prescribed frequency. ### Claim 3 (depends on 1) The system of claim 1, wherein the carriage has a natural resonant frequency and wherein the spring has a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 95% of the carriage natural resonant frequency. ### Claim 4 (depends on 3) The system of claim 3, wherein the carriage has a natural resonant frequency and wherein the spring has a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 50% of the carriage natural resonant frequency. ### Claim 5 (depends on 1) The system of claim 1, wherein the drive belt includes a protrusion, and wherein the spring is located in contact with the protrusion, and wherein the drive force is coupled to the carriage from the drive belt through the contact between the protrusion and the spring. ### Claim 6 A carriage scanning system, comprising: a carriage which moves along a carriage path; a first spring and a second spring mounted to the carriage; a drive motor which generates a drive force; and a drive belt which is coupled to the drive motor and which is elastically coupled to the carriage through the first spring and the second spring, the drive belt coupling the drive force to the carriage to cause the carriage to move along the carriage path, wherein the drive belt includes a protrusion, and wherein the first spring and second spring are in contact with the protrusion; wherein the first spring and second spring isolate the carriage from vibrations occurring within the drive belt. ### Claim 7 (depends on 6) The system of claim 6, wherein the first spring is a low pass filter of mechanical vibrations which filters out frequencies greater than a prescribed frequency. ### Claim 8 (depends on 7) The system of claim 7, wherein the carriage has a natural resonant frequency and wherein the first spring and the second spring each have a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 95% of the carriage natural resonant frequency. ### Claim 9 An inkjet printing system for printing to a media sheet, comprising: a frame; a carriage rod mounted to the frame; a carriage which moves along the carriage rod; an inkjet pen mounted within the carriage for ejecting ink drops during movement of the carriage along the carriage rod; a spring mounted to the carriage; a drive motor which generates a drive force; a drive belt coupled to the drive motor and the spring, the spring serving as a link which elastically couples the drive belt to the carriage, the drive belt coupling the drive force to the carriage through the spring to cause the carriage to move along the carriage path; and means for isolating the carriage from vibrations occurring within the drive belt, the isolating means comprising the spring. ### Claim 10 (depends on 9) The system of claim 9, wherein the spring is a low pass filter of mechanical vibrations which filters out frequencies greater than a prescribed frequency. ### Claim 11 (depends on 9) The system of claim 9, wherein the carriage has a natural resonant frequency and wherein the spring has a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 95% of the carriage natural resonant frequency. ### Claim 12 (depends on 11) The system of claim 11, wherein the carriage has a natural resonant frequency and wherein the spring has a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 50% of the carriage natural resonant frequency. ### Claim 13 (depends on 9) The system of claim 9, wherein the drive belt includes a protrusion, and wherein the spring is located in contact with the protrusion, and wherein the drive force is coupled to the carriage from the drive belt through the contact between the protrusion and the spring. ### Claim 14 A document scanning system, comprising: a frame; a carriage rod mounted to the frame; a carriage which moves along the carriage rod; an optical sensor mounted to the carriage for scanning a document during movement of the carriage along the carriage rod; a spring mounted to the carriage; a drive motor which generates a drive force; a drive belt coupled to the drive motor and the spring, the spring serving as a link which elastically couples the drive belt to the carriage, the drive belt coupling the drive force to the carriage through the spring to cause the carriage to move along the carriage path; and means for isolating the carriage from vibrations occurring within the drive belt, the isolating means comprising the spring. ### Claim 15 (depends on 14) The system of claim 14, wherein the spring is a low pass filter of mechanical vibrations which filters out frequencies greater than a prescribed frequency. ### Claim 16 (depends on 14) The system of claim 14, wherein the carriage has a natural resonant frequency and wherein the spring has a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 95% of the carriage natural resonant frequency. ### Claim 17 (depends on 16) The system of claim 16, wherein the carriage has a natural resonant frequency and wherein the spring has a spring constant prescribed to isolate the carriage from vibrations in the drive belt which have a frequency that are at least 50% of the carriage natural resonant frequency. ### Claim 18 (depends on 14) The system of claim 14, wherein the drive belt includes a protrusion, and wherein the spring is located in contact with the protrusion, and wherein the drive force is coupled to the carriage from the drive belt through the contact between the protrusion and the spring.