# US 7,607,847 B2 · Printer capable of stable printing without pitch fluctuations and paper carrying mechanism therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,847 B2 - Document ID: US7607847B2 - Status: Granted - Kind: B2 - Application number: 11/519,870 - Filed: 2006-09-13 - Published: 2007-03-15 - Granted: 2009-10-27 - Earliest claimed: 2005-09-14 - Assignees: NEC Infrontia Corporation - Inventors: Yukio Yoshioka - Web page: https://patentgrep.com/patent/US7607847B2 ## CPC - B41J 29/02: Framework - B41J 11/42: Controlling {printing material conveyance for accurate alignment of the printing material with the printhead; Print registering} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract In a printer including a base frame, an upper frame rotatably coupled to the base frame, and a platen and a platen pulley both rotatably supported by the upper frame, a subframe is attached to the upper frame rotatably and movably in one direction. A reduction gear and a belt pulley both are rotatably supported by the subframe. A drive gear is rotatably supported by the base frame and engaged with the reduction gear. A drive belt is stretched between the platen pulley and the belt pulley. A spring is attached between the upper frame and the subframe. The base frame has a guiding portion concentric with the drive gear. The subframe has a guided portion opposite the guiding portion. The spring applies tension to the drive belt and brings the guided portion into contact with the guiding portion. ## Claims ### Claim 1 A paper carrying mechanism for a printer which comprises: a base frame; an upper frame rotatably coupled to the base frame; a platen and a platen pulley both rotatably supported by the upper frame; a subframe attached to the upper frame rotatably and movably in one direction; a reduction gear and a belt pulley both rotatably supported by the subframe; a drive gear rotatably supported by the base frame and engaged with the reduction gear; a drive belt stretched between the platen pulley and the belt pulley; and a spring attached between the upper frame and the subframe, the base frame having a guiding portion concentric with the drive gear, the subframe having a guided portion opposite the guiding portion, the spring applying tension to the drive belt and brings the guided portion into contact with the guiding portion. ### Claim 2 (depends on 1) The paper carrying mechanism according to claim 1, wherein the subframe is attached to the upper frame by a structure such that a round shaft is fitted in an elongated hole. ### Claim 3 (depends on 1) The paper carrying mechanism according to claim 1, wherein the subframe has a fulcrum hole, the upper frame has a fulcrum shaft inserted in the fulcrum hole, the fulcrum hole is an elongated hole in the one direction, and the fulcrum shaft is a round shaft. ### Claim 4 (depends on 1) The paper carrying mechanism according to claim 1, wherein the guiding portion and the guided portion respectively have curved surfaces in contact with each other. ### Claim 5 (depends on 4) The paper carrying mechanism according to claim 4, wherein the curved surfaces face in the opposite direction from each other. ### Claim 6 (depends on 1) The paper carrying mechanism according to claim 1, wherein the guided portion is concentric with the reduction gear. ### Claim 7 (depends on 1) The paper carrying mechanism according to claim 1, wherein the base frame has a rib vertically provided on the inner bottom thereof, and the rib is a curved plate having the guiding portion. ### Claim 8 (depends on 1) The paper carrying mechanism according to claim 1, wherein the spring is a tension coil spring, and the tension coil spring has a first end hooked to the upper frame and a second end hooked to the subframe. ### Claim 9 (depends on 8) The paper carrying mechanism according to claim 8, wherein the upper frame has a protrusion, the subframe has a hole, the first end is hooked to the protrusion, and the second end is hooked to the hole. ### Claim 10 A printer comprising: a base frame; an upper frame rotatably coupled to the base frame; a platen and a platen pulley both rotatably supported by the upper frame; a subframe attached to the upper frame rotatably and movably in one direction; a reduction gear and a belt pulley both rotatably supported by the subframe; a drive gear rotatably supported by the base frame and engaged with the reduction gear; a drive belt stretched between the platen pulley and the belt pulley; and a spring attached between the upper frame and the subframe, the base frame having a guiding portion concentric with the drive gear, the subframe having a guided portion opposite the guiding portion, the spring applying tension to the drive belt and brings the guided portion into contact with the guiding portion. ### Claim 11 (depends on 10) The printer according to claim 10, wherein the subframe is attached to the upper frame by a structure such that a round shaft is fitted in an elongated hole. ### Claim 12 (depends on 10) The printer according to claim 10, wherein the subframe has a fulcrum hole, the upper frame has a fulcrum shaft inserted in the fulcrum hole, the fulcrum hole is an elongated hole in the one direction, and the fulcrum shaft is a round shaft. ### Claim 13 (depends on 10) The printer according to claim 10, wherein the guiding portion and the guided portion respectively have curved surfaces in contact with each other. ### Claim 14 (depends on 13) The printer according to claim 13, wherein the curved surfaces face in the opposite direction from each other. ### Claim 15 (depends on 10) The printer according to claim 10, wherein the guided portion is concentric with the reduction gear. ### Claim 16 (depends on 10) The printer according to claim 10, wherein the base frame has a rib vertically provided on the inner bottom thereof, and the rib is a curved plate having the guiding portion. ### Claim 17 (depends on 10) The printer according to claim 10, wherein the spring is a tension coil spring, and the tension coil spring has a first end hooked to the upper frame and a second end hooked to the subframe. ### Claim 18 (depends on 17) The printer according to claim 17, wherein the upper frame has a protrusion, the subframe has a hole, the first end is hooked to the protrusion, and the second end is hooked to the hole.