1. Field of the Invention
The present invention relates to a drive apparatus for a rotary member, an image forming apparatus, such as a copying machine, a facsimile machine, a printer, or other similar image forming apparatus, and a method of assembly for a drive apparatus for a rotary member.
2. Discussion of the Background
A known drive apparatus for a rotary member is shown in FIG. 11. The drive apparatus includes a drive motor (not shown), a drive shaft 120 driven by the drive motor and a transmission member 134 for transmitting a driven force by the drive shaft 120. The transmission member 134 transmits the driven force to a rotary member (not shown). The transmission member 134 has a cylinder-shaped portion that is mounted around the drive shaft 120. The transmission member 134 has a long hole 145. The drive shaft 120 has a small hole 147 in which a regulation pin 144 is inserted. The regulation pin 144 also is inserted in the long hole 145 of the transmission member 134 so that the transmission member 134 cannot rotate relative to the drive shaft 120. However, the transmission member 134 can slide along the drive shaft 120 in the axial direction of the drive shaft 120 because the hole of the drive shaft 120 is long in the axial direction.
When the drive apparatus for the rotary member is used, an engaging part of the rotary member has to engage with an engaging part of the transmission member 134 in order for the driving force of the drive shaft 120 to transmit to the rotary member. Even if the engaging part of the rotary member does not engage with the engaging part of the transmission member, each the engaging parts can be engaged if the drive shaft is rotated.
When the drive apparatus for the rotary member is assembled, the regulation pin 144 is inserted into the holes 145, 147 while the holes are overlapped. If the holes 145, 147 are not overlapped precisely, the pin 144 damages an edge 145A of the long hole 145.
Japanese laid-open publication 2001-193755 describes a long hole having a width that is larger for a purpose of preventing the pin from damaging the edge of the long hole. If the width of the long hole is larger, however, the gap between the pin and the long hole is larger. As a result, the rotary member moves irregularly.