A4 Twin Array Scanners Built By Others

The paper path is between the wood blocks and the metal carriage supporting the two
A4 CIS sensors. The upper blocks contain a pair of 8" ccft lamps, also mounted equally offset to fit the matched pair of A4 CIS arrays.
A divider immediately beneath the lamps supports an array of neutral density filters, more in the center than the ends, as these shorter
ccft lamps do not have absolutely even illumination end to end, contrary to what your eye might tell you.
The two ccft lamps are powered by a single inverter.

This view shows the removal of the optical encoder from the take-up roll. The roll is now "driven" by a capstan drive beneath the paper path.
Pressure is provided by a simple gravity drop block. The capstan drive stepper motor is controlled by its own stepper controller,
as is the take-up spool stepper motor. The rod about 2" behind the capstan shaft provides for a consistent paper path.
Note on extreme left the two one-turn pots to adjust the "exposure" of each of the 2 A4 CIS sensors.
The Mk3b electronics is unchanged, but the transmission now incorporates a slip-clutch to maintain an even tension on the roll for take-up.

This view shows the scanner loaded with a conventional 88n roll, showing how the pressure lever is lowered onto the paper
after the roll is loaded. The stepper motor and its controller are salvaged from a dead scanner, and connected to a conventional
player piano transmission. The transmission has been stripped of everything but the rewind lever to disengage the paper
for manual rewind. Note the simple manual rewind made from another gear from a salvaged player piano transmission.

This shows a close-up of the simple friction clutch made from a mix of player piano spool box parts and common hardware.
The set screw in the player piano drive gear has been removed, so that it freewheels with felt washers either side of it.
The tightness of the clutch is determined by best judgement position of the set screw collar forcing a small coil spring against a retainer.

This view shows the simple salvaged gear assembly (from Visioneer sheet-fed scanners) making it possible
to use a very modest stepper motor to provide the driving force.

The simplicity of source chucks is well illustrated here. The 2 chucks (drive and idle) are fully adjustable with simply lock screws.
This side shows the lightly loaded friction brake to keep the source side reasonably flat,
and a simple manual rewind made from common player piano spool box parts.
Note the fine centering adjustment on the left, 3 more pics of this follow.

This is the fine adjustment for centering rolls. The brass post is anchored, while the screw thread moves the entire chuck assembly.

This is a view of the underside of the fine adjust centering device. Note that the entire chuck assembly can be moved
about 3/8" either side of an eye-ball center.

This view illustrates both drive and idle chucks, the matched pair of A4 CIS
salvaged out of identical Canon EiDe flat bed scanners, and the rubber capstan drive.

This view shows the scanner loaded with a 15 1/4" Duo-Art reproducing pipe organ roll for scanning.
Note how the source chucks have been expanded to support the roll in a central position.

This is a view of a CIS file emerging from a scan of 176n Duo-Art reproducing pipe organ roll 15 1/4" wide.
Note that the twin array images side by side, in negative and positive. The right hand side of both images is the overlap area.
Think of the right (positive) side in a "flipped" orientation. The next step is to create a midi e-roll from this CIS file.

And this is a view, as displayed by Cakewalk, of the e-roll emerging out of the scanned Duo-Art reproducing pipe organ roll illustrated above.
Note the playing notes having a fixed velocity of 64, while the Duo-Art control codes have a fixed velocity of 3.

Here's the same scanner loaded with a narrow 6" Wurlitzer 125 band organ roll. Illustrates its flexibility.