Question 4
Use the sketch in Fig. 1 to answer question 4.
(a) Name the units labelled:
W;
X;
Y;
Z.
(b) State one function each of the following in the offset press operation:
(i) blanket cylinder;
(ii) delivery unit;
(iii) feeding unit.
(c) Mention one safety device available in the feeding unit.
(d) List three methods by which the machine can be lubricated.
Observation
Few candidates attempted this question and the performance was okay.
The solution is shown below:
(A) Names of the unit labelled:
- W = Inking unit
- X = Damping unit
- Y = Plate cylinder
- Z = Impression cylinder
(B)
- Blanket cylinder
- Carrier of blanket
- Receives ink from plate
- Transfers ink to paper
(ii) Delivery Unit
- Receives printed sheets, align sheets and drying of ink.
(iii) Feeding Unit
- Registers sheets for impression, separate sheet from pile.
- Forwarding sheets to the printing unit.
(C) Safety device available in feeding unit
- Censoring finger
- Double sheet detector
- No-sheet detector
(D) Method by which machine can be lubricated
- Manual lubrication
- Central lubrication
- Automatic or cascade lubrication