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Duplex Automatic Document Handler (DADH)
Overview
The Duplex Automatic Document Handler (DADH) is described under the following headings:
•
Counterbalances
•
Input Tray
•
Feeder
•
De-skew - Takeaway Rolls (TAR)
•
Constant Velocity Transport (CVT)
•
Duplex Inverter
•
Re-stack
•
Drives
•
Covers
•
Interlocks
Figure 1
and
Figure 2
show the component locations.
Counterbalances
Two counterbalance assemblies secure the document handler to the scanner frame. They are
the primary locators for the DADH to the scanner. Counterbalancing force is generated by
compression springs acting on a cam-follower arrangement, all housed within sheet metal
brackets. Above a set drop-down angle, the DADH will hold or rise slowly to the maximum
opening angle. Below the set drop-down angle, the DADH will gently close onto the scanner. In
addition, the counterbalance assemblies are double-hinged to allow a customer to close the
DADH onto books of up to 25 mm in thickness without applying excessive force to the docu-
ment glass of the scanner. This feature is known as book-mode operation
Input Tray
Copies are placed into the tray, face up, 1 to N order. The nominal capacity of the input tray is
50 originals of 75 GSM (20 lb.) weight. The minimum size original is A5 (5.5 X 8.5 inch), SEF or
LEF. The maximum size of original is A3 (11 X 17 inch), SEF only. The maximum weight is 120
GSM (30 lb.) The input tray is capable of accepting of 100 good condition originals, size up to
A4 or 8.5 X 11 inch, SEF or LEF, weight up to 80 gsm.
orientations. Intermixed lengths (feed direction) are acceptable for a limited number of docu-
ment pairs, which are described below in the 'Mixed Size Mode' section. The tray will provide
for centre feeding in 1 to N sequence. Movable tray guides for the width condition are provided.
Correct guide adjustment by the operator is imperative for reliable feeding and auto paper
select. The DADH document sensor, Q005-102, detects originals loaded against an input gate.
The gate moves out of the way prior to the feed of the first original and it remains so for the
entire job (see Feeder).
ColorQube® 9303 Family
Table 1
lists recognized paper sizes and
February 2013
Table 1 Document size
Document Size
SEF Document
A5
Y
5.5 x 8.5
Y
B5
Y
A4
Y
8.5 X 11
Y
8.5 X 13
Y
8.5 X 14
Y
B4
Y
A3
Y
11 X 17
Y
Document Size Sensing and Selection
Document size sensing and selection is achieved by a combination of:
•
Width sensing (cross-process direction).
•
Static and active length detection (process direction).
•
Customer selectable NVM settings.
•
"Mixed Length Mode" selection by operator.
Width Detection
Width sensing is accomplished by means of a variable linear potentiometer Q005-095. The
potentiometer slide is directly connected to one of the two paper width guides. The output sig-
nal from the potentiometer is converted into a physical dimension of the paper guide from the
paper path centre line.
This sensing method is sufficiently accurate to differentiate between document widths that dif-
fer by 8 mm or more.
Length Detection
Static length detection is used to determine document length for most (high percentage use)
document sizes and orientations. This is accomplished with two sensors, Q005-221 & Q005-
222, located in the input tray, which are at appropriate distances from the lead edge of the
paper stack. The state of these two stack length sensors, when documents are loaded in the
input tray at start of a job will determine the stack length range.
Active length detection is used to distinguish between 8.5 X 11 inch SEF and A5 (5.5 X 8.5
inch) LEF. Discrimination between these two sizes is accomplished by checking whether the
DADH feed sensor, Q005-204, is covered as the first document passes the DADH pre-reg
Sensor, Q005-206. If the DADH feed sensor senses a document at this point, then the 8.5 X 11
inch. size is indicated. If the sensor is clear, then A5 (5.5 X 11 inch) is indicated. Active length
detection is used only when conditions at the input guides and tray sensors indicate that there
is not enough information to determine document size and orientation.
An active "minimum length" check is also included, and any sheets shorter than 110 mm (cor-
responding to the longest distance between two successive nip rolls) will not be allowed to pro-
ceed beyond the upper portion of the paper path. A fault is declared and the customer is
informed to use the document glass to copy or scan the original(s).
8-35
LEF Document
Y
Y
Y
Y
Y
N
N
N
N
N
Principles of Operation
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