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TIMING DISK

IP.com Disclosure Number: IPCOM000026026D
Original Publication Date: 1989-Oct-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 4 page(s) / 166K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an electrophotographic printing machine, a timing disk is frequently used to control the angular rotation of the photoconductive drum used therein. The arrangement of disk 18 to generate timing signals for synchronizing the occurrence of the various machine processes and events with the rotation of drum 10 is shown in Figure 1. These signals are generated through the use of disk 18 secured to shaft 16 extending from drum 10 and aligned therewith. A plurality of lines are formed on the disk. Each line is opaque with the remainder of the disk being substantially transparent. The plurality of lines are formed on the disk photographically. Each line has a predetermined angular orientation with respect to a reference line, the reference line being oriented with respect to a predetermined position of drum 10.

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Page 1 of 4

EROX DISCLOSURE JOURNAL

TIMING DISK Proposed Abraham Cherian Classification

U.S. C1.355/14R Int. C1. G03g 15/00

Y

FIG. I

62 60

I

56

58

FIG. 2 W

62

16

FIG. 3a FIG. 36

Volume 14 Number 5 SeptembedOctober 1989 25 1

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

Page 2 of 4

TIMING DISK (Cont'd)

In an electrophotographic printing machine, a timing disk is frequently used to control the angular rotation of the photoconductive drum used therein. The arrangement of disk 18 to generate timing signals for synchronizing the occurrence of the various machine processes and events with the rotation of drum 10 is shown in Figure 1. These signals are generated through the use of disk 18 secured to shaft 16 extending from drum 10 and aligned therewith. A plurality of lines are formed on the disk. Each line is opaque with the remainder of the disk being substantially transparent. The plurality of lines are formed on the disk photographically. Each line has a predetermined angular orientation with respect to a reference line, the reference line being oriented with respect to a predetermined position of drum 10.

Turning now to Figure 2, a light emitting diode 56 is positioned on one side of disk 18 with photosensor 58 being positioned on the opposite side of disk 18. Light emitting diode 56 is arranged to project light rays onto disk 18 in the region of lines 60. Photosensor 58 is positioned to receive the light rays transmitted through disk 18 with pulses being generated when the lines block the light rays. In this way, a series of electrical pulses are thus generated as drum 10 rotates. The occurrence and time of these pulses is related to the angular position of drum 10 with respect to reference line 62. These pulses comprise the event clock signal. A similar light emitting diode and photosensor (not shown) are also provided in position on opposite sides of disk 18 near reference line 62 for generating a single signal termed a pitch signal for each complete revolution of drum 10. The number of lines on disk 18 defines the number of events that occur with respect to predetermined rotational positions of drum 10. This number can vary in accordance with the specifics of the printing machine and its requirements. Each line is oriented on disk 18 to provide an output signal to initiate an event. The lines need not be equally spaced from one another.

Referring now to Figures 3a, there is shown an elevational view of disk 18. As shown thereat, disk 18 includes a plurality of lines 60 spaced from one another with a reference line 62 disposed thereon as well. Lines 60 and 62 are opaque with the remainder of disk 18 being substantially transparent. Disk 18 is made from a flexible, plastic photographic film. By way of example, disk 18 can be made from Mylar, a trademark of the DuPont Corporation. Lines 60 and 62 a...