A drive coupling and transmitting assembly for an image forming apparatus, comprising: a drive shaft configured to transmit a rotational driving force; and a coupling member comprising: a main drum body of variable size and shape having a flexible shaft subassembly including: a receiver having at least two engaging teeth (283,284), an adapter, and a flexible shaft member extended between the adapter and the receiver, wherein a first end of the shaft member is secured to a receiver post and a second end of the shaft member is secured to an upper end of the adapter; a bushing member slidably disposed between the main drum body and the flexible shaft subassembly, wherein the adapter is slidably disposed in the bushing member and configured with at least one rotational force transmitting pin to engage with a spiral groove disposed on the bushing member such that the bushing member is moved longitudinally inward or outward while installing or detaching the main drum body and the at least one rotational force transmitting pin is rotated by the drive shaft or a compression and torsion spring in the spiral groove in a clockwise or counterclockwise direction; wherein the receiver is configured to receive the rotational driving force from the drive shaft and transmit the rotational driving force through the flexible shaft member to the adapter such that the main drum body, the bushing member and the flexible shaft subassembly are rotated about an axis; characterized in that the main drum body and the bushing member are connected by a plurality of straight, non-tapered, interval, longitudinal spline grooves and a plurality of straight, non-tapered, interval, longitudinal splines configured to slide axially to each other and transmit the rotational driving force about the axis. a drive shaft configured to transmit a rotational driving force; and a coupling member comprising: a main drum body of variable size and shape having a flexible shaft subassembly including: a receiver having at least two engaging teeth (283,284), an adapter, and a flexible shaft member extended between the adapter and the receiver, wherein a first end of the shaft member is secured to a receiver post and a second end of the shaft member is secured to an upper end of the adapter; a bushing member slidably disposed between the main drum body and the flexible shaft subassembly, wherein the adapter is slidably disposed in the bushing member and configured with at least one rotational force transmitting pin to engage with a spiral groove disposed on the bushing member such that the bushing member is moved longitudinally inward or outward while installing or detaching the main drum body and the at least one rotational force transmitting pin is rotated by the drive shaft or a compression and torsion spring in the spiral groove in a clockwise or counterclockwise direction; a main drum body of variable size and shape having a flexible shaft subassembly including: a receiver having at least two engaging teeth (283,284), an adapter, and a flexible shaft member extended between the adapter and the receiver, wherein a first end of the shaft member is secured to a receiver post and a second end of the shaft member is secured to an upper end of the adapter; a bushing member slidably disposed between the main drum body and the flexible shaft subassembly, wherein the adapter is slidably disposed in the bushing member and configured with at least one rotational force transmitting pin to engage with a spiral groove disposed on the bushing member such that the bushing member is moved longitudinally inward or outward while installing or detaching the main drum body and the at least one rotational force transmitting pin is rotated by the drive shaft or a compression and torsion spring in the spiral groove in a clockwise or counterclockwise direction; wherein the receiver is configured to receive the rotational driving force from the drive shaft and transmit the rotational driving force through the flexible shaft member to the adapter such that the main drum body, the bushing member and the flexible shaft subassembly are rotated about an axis; characterized in that the main drum body and the bushing member are connected by a plurality of straight, non-tapered, interval, longitudinal spline grooves and a plurality of straight, non-tapered, interval, longitudinal splines configured to slide axially to each other and transmit the rotational driving force about the axis.