Konica Minolta BIZHUB 750 Service Manual page 72

14. PAPER FEED SECTION (trays 1 and 2)
C. Paper loop mechanism
Paper that passed through the feed roller [5] and the separation roller [3] is sent out to the pre-registration roller
[7]. The paper thus sent out presses the actuator [1] to turn ON the paper feed sensors /1 (PS1) and /2 (PS7) [6].
By stopping the paper feed roller a specified period of time after PS1 and PS7 turn ON, the paper forms a loop
[2] short of the pre-registration roller to correct the skew of paper.
[1] Actuator
[2] Paper loop
[3] Separation roller
[4] Pick-up roller
D. Pre-registration control
The pre-registration roller is driven by the paper feed motor (M1) through the pre-registration clutches /1 (CL4)
and /2 (CL6). Turning ON and OFF the CL4 and CL6 transmits and shuts off the drive force to rotate and stop
the motor.
From the moment when the paper feed sensors /1 (PS1) and / (PS7) turn ON [2] until the paper feed clutches /1
(CL3) and /2 (CL5) turn OFF [3] while in the pick-up control, CL4 and CL6 turn OFF and the pre-registration roller
stops. In this way, the paper thus conveyed from the feed roller hits against the pre-registration roller and a loop
is formed to correct the skew of paper.
After formation of the loop, CL4 and CL6 turn ON [4] a specified period of time after a print start signal [1] is out-
put to rotate the pre-registration roller for pre-registration. At the same time, CL3 and CL5 turn ON [5] for a short
period of time to rotate the feed roller and assist the conveyance until the pre-registration roller nips the paper
securely.
When the 1st sheet of paper passes through PS1 and PS7 and they turn OFF [6], CL4 and CL6 also turn off to
complete the pre-registration of the 1st sheet of paper. This timing becomes a starting point for the pick-up of
the 2nd sheet of paper [7] and the control of the pre-registration [8].
46
[4] [5] [6]
[3] [2]
Theory of Operation Ver1.0 Aug.2005
[7]
[1]
[5] Feed roller
[6] Paper feed sensors 1/ (PS1), /2 (PS7)
[7] Pre-registration roller
57aat2c038na