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ILLUMINATION SLIT FOR A REPRODUCING MACHINE

IP.com Disclosure Number: IPCOM000023430D
Original Publication Date: 1977-Oct-31
Included in the Prior Art Database: 2004-Mar-30
Document File: 4 page(s) / 661K

Publishing Venue

Xerox Disclosure Journal

Abstract

An improved exposure slit system 1 for controlling the pro-jected image illumination of an optical system of a repro-ducing machine, The optical system is arranged to strip-wise view an original. The exposure slit system 1 includes one illumination slit member 2 arranged along the optical ray path near the object plane, for example, just below the platen 3 of a copier as in Figure 1. A second illumination slit member 4 is arranged along the optical ray path near the image plane, for example, just above a photosensitive surface 5 as shown in Figure 2, The exposure slit profile for controlling illumi=- nation at the image plane in one mode of operation is com-prised in part by a portion of the profile of the exposure slit member 4 at the image plane and in part by a portion of the profile of the exposure slit member 2 near the object plane as projected at the image planes

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Page 1 of 4

XEROX DISCLOSURE JOURNAL

ILLUMINATION SLIT FOR A
REPRODUCING MACHINE
Robert F~ Allis

/0'

Volume 2 Numbe: 5

Proposed Classification
U~S~Cl~ 355/55
Into Cl~ G03b 27/52

September/October 1977 113

FIG. /

F/Ge 2

FIG. 3

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

Page 2 of 4

ILLUMINATION SLIT FOR A REPRODUCING MACHINE (Cont~d)

An improved exposure slit system 1 for controlling the pro~
jected image illumination of an optical system of a repro~-
ducing machine, The optical system is arranged to strip~-wise
view an original. The exposure slit system 1 includes one
illumination slit member 2 arranged along the optical ray path
near the object plane, for example, just below the platen 3 of
a copier as in Figure 1. A second illumination slit member 4
is arranged along the optical ray path near the image plane,
for example, just above a photosensitive surface 5 as shown in
Figure 2, The exposure slit profile for controlling illumi=~
nation at the image plane in one mode of operation is com-~
prised in part by a portion of the profile of the exposure slit
member 4 at the image plane and in part by a portion of the
profile of the exposure slit member 2 near the object plane as
projected at the image planes

This system is particle adapted for use in reproducing
machines wherein the optical system is capable of providing
selectively one of a plurality of copy image magnifications.
In such machines the exposure slit profile required for dif~
ferent projected image magnifications varies because of the
change in the image size, For example, for reduced sized
images, the illumination is concentrated into a smaller area,

Figure 1 shows an object plane slit 2 as viewed along the
optical ray path looking up at the platen 3 of a copier. The
illumination slit 2 includes two transverse slit profile
boundaries 6 and 7 which serve to define the width of the slit,
For purposes of illustration, the boundaries have been shown
as being slightly different in profile, One of the boundaries
7 has a curved shape whereas the other 6 comprises the inter~
section of two lines, Any desired boundary profile could be
used to provide the appropriate slit profile. A butter~fly
type profile wherein the slit is wider at the ends than in the
middle is preferred,

The back projected image of the operative slit boundary 8 o...