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DRIVE AND TIMING STRATEGY FOR A CVT IMAGE INPUT TERMINAL WITH AUTOMATIC DOCUMENT FEEDING

IP.com Disclosure Number: IPCOM000025825D
Original Publication Date: 1988-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 141K

Publishing Venue

Xerox Disclosure Journal

Abstract

To provide full scale (1x1 or magnified (2x1 imaging and continuous tone image scanning in an Image Input Terminal, a variable slow scan speed capability is required in order to operate within system data rate limitations. The variable scan speed should preferably be available in both a first scanning mode where the document rests on the platen while being scanned and in a second scanning mode where the document is advanced across a scan slit by the Controlled Velocity Transport (CVT) of an Automatic Document Feeder (ADF).

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EROX DISCLOSURE JOURNAL

DRIVE AND TIMING STRATEGY FOR A CVT IMAGE INPUT TERMINAL WITH AUTOMATIC DOCUMENT FEEDING
William H. Bruce, Jr.

Douglas G. Wiggins

Proposed Classification

U.S. C1.271/266 Int. C1. B65h 5/12

Volume 13 Number 3 May/June 1988 119

[This page contains 1 picture or other non-text object]

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DRIVE AND TIMING STRATEGY FOR A CVT IMAGE INPUT TERMINAL WITH AUTOMATIC DOCUMENT FEEDING (Cont'd)

To provide full scale (1x1 or magnified (2x1 imaging and continuous tone image scanning in an Image Input Terminal, a variable slow scan speed capability is required in order to operate within system data rate limitations. The variable scan speed should preferably be available in both a first scanning mode where the document rests on the platen while being scanned and in a second scanning mode where the document is advanced across a scan slit by the Controlled Velocity Transport (CVT) of an Automatic Document Feeder (ADF).

A strategy is proposed here which provides universal drive and timing for document feeding and scanning in the ADF/CVT scanning mode independent of scan speed variations.

In this concept, stepper motors are used as the drive source for both the ADF and the CVT drives. All feed control functions (e.g., timing, feedrate, jam recognition) are defined in terms of motor steps and related to feed per motor step for each drive. Step commands, and synchronization for both motors and drives are provided by a single machine controller, with various sensors providing paper path monitoring. Feature selection (e.g., full scale, magnified, or continuous tone image scanning) via a user interface permits input of the required scan speed information to the machine controller which in turn supplies the necessary step frequency for the previously defined feed control sequence.

Therefore, unlike conventional synchronous motor drives, this concept provides a simplified system control sequence which remains independent of the scan speed, requires only step frequency input to accomplish scan speed variation, and supplies the necessary synchronization and interaction between feeding and scanning systems.

Referring to the drawing Figure, at start up, ADF drive is initiated to feed the document 5 A/X motor steps (a distance 'A') from the nip of the feed belt 7 to...