Paper Feed Mechanism - Star Micronics LC-7211 Technical Manual

4-4. Paper Feed Mechanism

The paper feed mechanism consists of a paper feed motor, an idler gear, a platen and a traction unit.
The paper feed motor is a PM (Permanent Magnet) 4-phase and 48 pulse motor.
There are two ways of feeding paper into the printer: the friction method and the tractor method. You can select the
method you want to use by setting the release lever on the optional push tractor unit.
• Friction Method
Friction method is selected when the release lever is position [1].
With this method, paper is pressed between the platen roller and the holder roller therefore, paper is fed as the rollers
turn.
As the paper feed motor is driven, the motor gear, through the idler gear, turns the platen gear in the paper feeding
direction. However, since the tractor gear and the tractor clutch are not linked at this time, the tractor unit will not
be driven.
• Tractor Method
Tractor method is selected when the release lever is position [2].
Paper feeding is facilitated by rotation of the sprocket pin of the tractor unit. When the tractor method is selected,
the PF idler gear is linked to the PF idler gear, enabling the drive force generated by the paper feed motor to be
transferred to the tractor unit via the idler gear.
Position of release lever
Engaement of the PF idler gear
Status of the PF roller and
PF roller
Release lever position detector
Paper feeding method
Fig. 2-7 Paper Feed Mechanism
[1]
Not linked
Pressed
Open
Friction
– 25 –
[2]
Linked
Not
Closed
Tractor