Cassette Paper Feed Block Learning each control and mechanism in the paper feed and transport system

1. Cassette Paper Feed Block

The cassette paper feed block feed printing paper from Cassette 1 or 2 into the machine.

Printing paper is loaded on the middle plate. The lifter plate lifts the middle plate to raise printing paper to the feed height. At paper feed, the paper feed roller goes down to the paper surface and rotates to feed the printing paper. From the fed paper, the separation roller transports only one sheet to the resist roller.

The configuration of this block is explained with controls and functions below.

1] Cassette paper presence/absence detection sensor

[2] Paper feed roller (Roller A)

[3] Transport roller (Roller B)

[4] Separation roller (Roller C)

[5] Paper feed vertical path roller

[6] Cassette retry paper sensor

[7] Vertical path guide

[8] Lower right cover

[9] Middle plate

[10] Lifter plate

No.	Name	Description	Details
1	Paper size detection	Detects paper loaded on Cassette 1 or 2.
2	Paper level detection	Detects the level of printing paper loaded on Cassette 1 or 2.
3	Lift-up operation	Lifts the middle plate with the lifter plate and keeps the paper surface at a constant height.	-
4	Paper feed roller up-down operation	Lowers the paper feed roller to the paper surface at paper feed.	-
5	Multi-feed prevention	Prevents multi-fed printing paper.

The control and function of each section are explained below.

a. Paper size detection

This machine can detect the size of paper loaded on a cassette.

For cassette paper size detection, the DC controller monitors output from the four-series actuator (SW0 to SW3) on the cassette size detection circuit board [3].

A cassette has a dial to indicate the paper size. When the cassette size dial is moved, SW0 to SW3 on the cassette size detection circuit board of the printer side become ON or OFF. This allows paper size detection from the combination of ON and OFF. If no cassette is loaded, the no cassette status is detected because SW0 to SW3 become all OFF.

For switching between the AB series and the inch series, the AB/inch series selection switch is used. If a cassette is mounted on the main unit, the cassette size detection switch recognizes either the AB series or the inch series.

1] AB/inch series selection switch

[2] Cassette size dial

[3] Cassette size detection circuit board

b. Paper level detection

This machine can detect the paper level on a cassette.

For cassette paper level detection, the DC controller monitors output from paper level detection sensors A and B and the paper presence/absence detection sensor.

Paper level detection sensors A and B are covered with the paper level sensor flag that move with the lifter gear. As the lifter gear moves, output from paper level detection sensors A and B varies. The DC controller judges the paper level by checking the changes of output from paper level detection sensors A and B.

A paper tray has a paper presence/absence detection sensor flag. If printing paper on the cassette has been used up, the paper presence/absence detection sensor flag moves and the paper presence/absence detection sensor changes from OFF to ON. In this case, the DC judges no paper on the cassette.

The position of each part used for paper level detection and the relationship between the sensor flag position corresponding to the paper level and the sensor output are as follows: