Drive transmission mechanism and drive transmission mechanism for printer apparatus

Abstract

It is a drive transmission mechanism for a printer apparatus, which has a conveying roller gear connected to a conveying roller, an intermediate gear including a small-diameter intermediate gear portion for rotating the conveying roller gear, and an intermediate gear supporting shaft rotatably supporting a shaft insertion hole of the intermediate gear. In this mechanism, the conveying roller gear includes a conveying roller gear circular portion having a diameter that is substantially equal to the reference pitch circle diameter of the conveying roller gear. The intermediate gear includes a small-diameter intermediate gear circular portion having a diameter that is substantially equal to the reference pitch circle diameter of a small-diameter intermediate gear portion. Further, the intermediate supporting shaft is mounted therein in such a manner as to provide a predetermined fitting clearance between the intermediate supporting shaft and the shaft insertion hole.

1 . A drive transmission mechanism for a printer apparatus comprising: 
 a metallic conveying roller for conveying sheets;    a resin conveying roller gear connected to one end portion of the conveying roller;    a resin intermediate gear, provided with a shaft insertion hole, for rotating the conveying roller;    a resin drive transmission gear, mounted on a drive shaft of a motor, for rotating the intermediate gear as the motor is driven; and    an intermediate gear supporting shaft for rotatably supporting the shaft insertion hole of the intermediate gear, wherein:    the intermediate gear includes a first-side intermediate gear portion meshed with the conveying roller gear, and also includes a second-side intermediate portion meshed with the drive transmission gear;    the intermediate gear is disposed in a position, in which the intermediate gear is caused by a load of the conveying roller to bite into the conveying roller gear and the drive transmission gear, when the gears are driven;    the resin conveying roller gear includes a conveying roller gear circular portion that is provided integrally with the conveying roller gear and that has a diameter being substantially equal to a reference pitch circle diameter of the conveying roller gear;    the resin drive transmission gear includes a drive transmission gear circular portion that is provided integrally with the drive transmission gear and that has a diameter being substantially equal to a reference pitch circle diameter of the drive transmission gear;    the resin intermediate gear further includes a first-side intermediate gear circular portion, which is provided integrally with the drive transmission gear and has a diameter being substantially equal to a reference pitch circle diameter of the first-side intermediate gear portion, and also includes a second-side intermediate gear circular portion that is provided integrally with the intermediate gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second-side intermediate gear portion;    the intermediate gear supporting shaft is mounted in the shaft insertion hole of the intermediate gear in such a way as to provide a predetermined fitting clearance between the intermediate gear supporting shaft and the shaft insertion hole;    the conveying roller gear circular portion is disposed in such a way as to be in contact with the first-side intermediate gear circular portion when the gears are driven; and    the drive transmission gear circular portion is disposed in such a manner as to be in contact with the second-side intermediate gear circular portion when the gears are driven.    
     
     
         2 . A drive transmission mechanism comprising: 
 a first gear; and    a second gear having a second first-side gear portion for rotating the first gear, wherein:    the first gear includes a first circular portion that is provided integrally with the first gear and that has a diameter being substantially equal to a reference pitch circle diameter of the first gear;    the second gear includes a second first-side circular portion that is provided with the second first-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second first-side gear portion; and    the first circular portion is disposed in such a way as to be in contact with the second first-side circular portion when the gears are driven.    
     
     
         3 . The drive transmission mechanism according to  claim 2 , further comprising: 
 a shaft insertion hole included the second gear; and    a second gear supporting shaft mounted in such a manner as to rotatably support the shaft insertion hole and as to provide a predetermined fitting clearance between the second gear supporting shaft and the shaft insertion hole.    
     
     
         4 . The drive transmission mechanism according to  claim 2 , further comprising: 
 a third gear for rotating the second gear, wherein    the second gear further includes a second second-side gear portion meshed with the third gear, and also includes a second second-side circular portion that is provided integrally with the second second-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second second-side gear portion;    the third gear includes a third circular portion that is provided integrally with the third gear and that has a diameter being substantially equal to a reference pitch circle diameter of the third gear; and    the second second-side circular portion is disposed in such a manner as to be in contact with the third circular portion when the gears are driven.    
     
     
         5 . The drive transmission mechanism according to  claim 2 , wherein 
 the second first-side circular portion is provided integrally with the second first-side gear portion