U.S. patent number 3,758,774 [Application Number 05/264,093] was granted by the patent office on 1973-09-11 for illumination system for copier machines arranged to minimize glare with respect to an operator.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to Leon H. Hildenbrandt.
United States Patent |
3,758,774 |
Hildenbrandt |
September 11, 1973 |
ILLUMINATION SYSTEM FOR COPIER MACHINES ARRANGED TO MINIMIZE GLARE
WITH RESPECT TO AN OPERATOR
Abstract
The present case is directed to a number of illumination systems
making use of lamps and reflectors having predetermined optical
configurations and arranged to insure minimal glare in the eyes of
an operator using the equipment in which the illumination systems
are incorporated. A first version involves a stationary paraboloid
reflector cooperating with a moving parabolic cylinder reflector to
illuminate an original document during a copying operation. In a
second version, the moving reflector is split into two reflectors
each having distinct parabolic configurations and different focal
lengths. In still another version, only a single reflector is
arranged for movement during scanning of an original document to
project a line of light and has a predetermined configuration which
is parabaloid in one direction and substantially elliptical in a
direction transverse to the first direction.
Inventors: |
Hildenbrandt; Leon H.
(Lexington, KY) |
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
23004542 |
Appl.
No.: |
05/264,093 |
Filed: |
June 19, 1972 |
Current U.S.
Class: |
362/277;
359/212.2; 355/67; 399/206 |
Current CPC
Class: |
G03B
27/526 (20130101); G03G 15/30 (20130101) |
Current International
Class: |
G03G
15/30 (20060101); G03B 27/52 (20060101); G03G
15/00 (20060101); G03b 027/54 () |
Field of
Search: |
;355/8,67 ;350/6
;353/50,98 ;240/103,41.35 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,560,172 |
|
Mar 1969 |
|
FR |
|
575,449 |
|
May 1959 |
|
CA |
|
Other References
Bruce, G. D. et al., "Dual-Mirror Document Scanning System," IBM
Tech. Disclosure Bul., Vol. 14, No. 6, pg. 1791., (Nov. 1971).
.
Bersot, J. D. et al., "Illumination to Eliminate Shadows," IBM
Tech. Disclosure Bul., Vol. 15, No. 2, pg. 521, (July
1972)..
|
Primary Examiner: Matthews; Samuel S.
Assistant Examiner: Harris; Michael D.
Claims
What is claimed is:
1. An illumination system for establishing a line of light
substantially coextensive with a linear exposure station having a
predetermined finite length within a light zone, comprising:
a light source;
a paraboloid reflector formed to receive light from said source and
to project in a first light path a beam of light of substantially
rectangular cross-section having a relatively long first dimension
and a relatively short second dimension, said relatively long
dimension corresponding to said predetermined finite length;
a parabolic reflector formed to receive said substantially
rectangular beam of light and to project a line of light therefrom
corresponding to said predetermined finite length;
first means mounting said light source and said paraboloid
reflector in order to project said substantially rectangular beam
of light to said parabolic reflector in said first light path and
within said light zone; and
second means mounting said parabolic reflector to re-form and
re-direct along a second path said substantially rectangular beam
of light as a line of light of said predetermined finite length and
to project said line of light to said exposure station, whereby
light is confined essentially within said light path and light
scattering is minimized.
2. The system of claim 1 wherein exposure is required in an
exposure plane and wherein said first means mounts said paraboloid
reflector to direct said beam of light in a light path that is
parallel to said exposure plane, and further comprising:
moving means for reciprocating said mounted parabolic reflector in
said first light path and in a substantially parallel plane with
respect to said exposure plane, in order to move said line of light
in said exposure plane during reciprocation of said parabolic
reflector.
3. The system of claim 2 wherein said exposure plane accomodates an
original document in a copier and wherein reciprocation of said
parabolic reflector is performed in order to scan said original
document and project information from said document for copying
purposes.
4. The system of claim 1 wherein said parabolic reflector comprises
a pair of parabolic reflectors and further comprising:
means mounting said pair of parabolic reflectors for reduction of
light to said exposure station at different angles to minimize
shadow effects.
Description
REFERENCES TO PATENTS, PENDING APPLICATIONS, AND PUBLICATIONS OF
INTEREST
Book: Calculus With Analytic Geometry having Angus E. Taylor and
Charles J. A. Halberg, Jr. as authors; copyright 1969, published by
Prentice-Hall, Inc. Note pages 85-91.
U. S. Pat. application Ser. No. 209,326, filed Dec. 17, 1971;
having R. V. Davidge, et al., as inventors; and entitled:
"Reproduction Apparatus Incorporating Alternate Redevelopment and
Reimaging Cycles for Multiple Copies."
U. S. Pat. application Ser. No. 209,039, entitled
"Electrophotographic Development Apparatus," Allison H. Caudill,
inventor, filed Dec. 17, 1971.
BACKGROUND OF THE INVENTION, FIELD, AND PRIOR ART
A variety of illumination schemes have been provided in the prior
art ranging all the way from simple aperture lamp arrangements,
making use of no reflectors to more complex systems making use of a
linear lamp position within an elliptical reflector and, in some
cases, making use of additional reflecting members to achieve
projection of the light in a preferred direction. In some cases, a
multiplicity of lamps have been arranged to illuminate an original
document cooperating with a closely positioned reflector element
that is co-extensive with the lamps. Ordinarily, in any copier
machine, when a flat document, such as original letters, and the
like, are placed in position for copying purposes, little or no
light is projected from the illumination system toward the
operator's eyes. However, under circumstances where the original
comprises a book or comparable original requiring special
positioning or handling, prior systems are prone to project light
toward the operator's eyes. This is due to the fact that the book
or comparable original is positioned on the copy machine with the
document lid in an open condition thereby permitting light to
escape from the interior of the machine during the copying
operation.
SUMMARY OF THE INVENTION
In accordance with the present invention, various illumination
arrangements are provided that establish light patterns within
pre-selected light boundaries not normally encountered by the
operator of the machine. More specifically, reflector elements are
provided in the illumination systems set forth therein that
cooperate in various respects to establish an original document
illumination pattern that is characterized as a directed column of
light, also referred to as collimated in nature. With this
arrangement, the chance that an operator of the machine will see
the light emanating from the machine under normal conditions is
extremely unlikely. This is true when original documents such as
letters and the like are being copied with a document cover in
place as well as under circumstances when books or other relatively
large documents are being copied with the document cover moved out
of position thereby exposing the illumination system. The
principles set forth herein are applicable even when a very small
original document is positioned for copying, or when in fact no
document is in place but the illumination system happens to be on.
The latter condition might occur, for example, during test
procedures or the like.
As previously indicated, the invention is illustrated in several
versions. In a first version, the illumination system includes a
stationary paraboloid reflector having an associated light source
that is preferably of compact design. Further, the first version
includes a single parabolic cylinder scanning reflector arranged
adjacent the original document for projection of a line of light
during copy operations. The moving reflector receives collimated
light from the stationary paraboloid reflector and focuses it to a
line of light. In the second version, a stationary paraboloid
reflector is also made use of but cooperates with a split parabolic
scanning mirror arrangement, comprising two parabolic cylinder
reflectors each having different focal lengths but focusing to the
same line during scanning operations. An objective of this
arrangement is to insure that light is provided from two
directions, thereby minimizing or eliminating shadow effects that
otherwise might be encountered with three-dimensional original
objects.
In a third version, the illumination system includes a single
moving reflector having both paraboloid and substantially
elliptical characteristics. In this version, the reflector is
preferably formed with a parabolic characteristic in one direction
transversely to the direction of scanning with respect to the
original document and that is substantially elliptical in
cross-sections that are parallel to the direction of scanning.
Reference is made to the Taylor and Halberg book for some
discussion of paraboloid and parabolic cylinder elements.
OBJECTS
A primary object of the present invention is to provide an
illumination system that substantially eliminates glare projected
toward the eyes of an operator in proximity to the system.
Another object of the invention is to provide an illumination
system incorporating cooperating elements of compact design and
achieving a more efficient illumination of objects.
Another object of the present invention is to provide an
illumination system for projecting a line of light onto an original
document in a copying machine.
A further object of the present invention is to provide an
illumination system having a minimum of moving elements but
producing a highly efficient light output for scanning of an
original document in a copier machine.
Also, an object of the present invention is to provide an
illumination system with some measure of control of light
distribution in the system.
A still further object of the present invention is to provide an
illumination system based on a unique arrangement of paraboloid and
parabolic reflector elements.
An additional object of the present invention is to provide an
illumination system having non-glare characteristics and utilizing
a single reflector means for controlled light distribution.
An object of the present invention is to provide an illumination
system that produces a more effective illumination pattern for
particular use with three-dimensional objects.
The foregoing and other objects, features, and advantages of the
invention will be apparent from the following more particular
description of various embodiments of the invention as illustrated
in the accompanying drawings.
IN THE DRAWINGS
FIG. 1 is a schematic diagram of an electrostatic transfer
reproduction apparatus incorporating a cyclic control unit for
automatically effecting alternate redevelopment and reimaging
cycles, and incorporating illumination means predicated on the
principles of the present invention.
FIG. 2a represents tracings of light rays from an original light
source to a stationary paraboloid reflector to a moving parabolic
reflector, thence through a document glass to an original
document.
FIG. 2b is similar to FIG. 2a but is representative of light ray
traces where a split reflector scheme is used involving two
parabolic cylinders arranged for movement during scanning. This
also illustrates the light being projected to an original document
from two different angles to minimize shadow effects.
FIGS. 3a, 3b, and 3c together represent a first version of the
illumination scanning arrangements previously referred to and
particularly making use of a moving parabolic cylinder
reflector.
FIG. 4 represents a typical illumination arrangement of the prior
art utilizing an elliptic cylinder reflector with a linear light
source.
FIGS. 5a and 5b represent a third version of an illuminating scheme
according to the principles of the present invention making use of
a single moving reflector serving the same objective of the other
versions, that is controlling the light from a substantially
compact or near-point source of light to maintain the light within
predetermined light projection boundaries in order to minimize or
eliminate glare that might otherwise occur. In doing this, light is
collimated as viewed in one plane and focused in a perpendicular
plane.
GENERAL DESCRIPTION
Referring now to FIG. 1 of the drawings, a continuously operating
electrostatic transfer reproduction apparatus incorporating a first
version of an illumination system is depicted. Although illustrated
in conjunction with a particular copier apparatus, as taught in the
Davidge, et al case, the illumination systems of the present
invention are adaptable to many kinds of copiers and scanning
systems.
Before discussing the illumination system, a general description of
the copier apparatus shown is in order. The copier apparatus
comprises a plurality of processing stations located about a
cylindrically shaped photosensitive electrostatic plate of drum
member 11. Drum member 11 comprises a layer of photoconductive
material superimposed over a conductive backing. A suitable
photoconductive material is disclosed in U. S. Pat. No. 3,484,237,
issed Dec. 16, 1969. Member 11 is divided into three segments or
frames designated A, B, and C. The frames are separated from one
another by interframe or intersegment gaps a, b, and c.
A sensing device 13 senses permanently recorded signals within the
interframe gap portion of the electrostatic place and supplies
logical signals to a cyclic control apparatus to be described
hereinafter indicating the positional relationship of the various
frames with respect to the various processing stations, as the
electrostatic plate rotates in the direction of arrow 15 past the
processing stations. The electrostatic plate 11 first passes a
cleaning station 17 having an actuable cleaning member 19 located
therein. When actuated, the cleaning member 19 brushes the surface
of the electrostatic plate 11 removing any foreign material
including developer material therefrom. The plate then passes an
actuable charging station consisting of a corona generating device
21 which sensitizes the electrostatic plate 11 as it rotates
therepast. Thereafter, the electrostatic plate passes an imaging
station 23 which, when actuated, projects a light image of a master
25 onto a frame segment of member 11 rotating thereunder. The
projection of the light image onto the sensitized electrostatic
plate creates a latent electrostatic image thereon which rotates
with member 11 as it passes the developer station 27. At the
developer station 27, multicomponent developer material including
an electrostatically charged toner is applied to the surface of the
electrostatic plate containing the electrostatic image thereon. The
charged toner particles are preferentially attracted to the latent
image on the plate 11 and are subsequently transferred to a
substrate surface 29 at the transfer station 31.
As will be described hereinafter, the frame containing the latent
electrostatic image which had been imaged at the imaging station 23
is not cleaned at the cleaning station 17 as it again rotates
therepast, nor is it charged at the actuable charging station 21 as
it again rotates therepast. Further, as will be described, the
imaging station 23 incorporates a moving optical projection system
33 which is reset to its initial position as the previously imaged
frame rotates past the imaging station 23. Since the initial latent
electrostatic image remains basically intact (that is, not being
disturbed at the cleaning station 17 or the charging station 21 or
re-exposed at the imaging station 23), the image is redeveloped at
the developing station 27 and the thusly redeveloped image is
transferred to a second substrate surface at the transfer station
31. Thereafter, the segment containing the image is cleaned at the
cleaning station 17, charged at the charging station 21 and imaged
with the same master 25 at the imaging station. The operation thus
proceeds alternately imaging and redeveloping a previously imaged
segment until the requisite number of copies of the master 25 have
been produced.
In the description immediately following, the detailed operation of
each of the processing stations located about the periphery of the
electrostatic plate 11 will be described. Thereafter will follow a
description of the cyclic control logic which effects the
sequential operation of each of the stations as the electrostatic
plate 11 rotates therepast.
The sensing device 13 senses indicia permanently recorded on the
edge portion of the electrostatic plate 11 at the interframe gaps
a, b and c. For example, this device could comprise a magnetic head
adapted to read magnetic signals recorded on the edge surface of
the plate. The output signal of this device is utilized to control
the sequencing of the various stations to be described
hereinafter.
The cleaning station 17 incorporates an actuable cleaning member 19
which moves from a position of close adjacency to the electrostatic
plate 11 to a second position remote from the electrostatic plate
11. The cleaning member could, for example, comprise a cleaning
brush well known in the art which intimately contacts the surface
of the electrostatic plate 11 and rotates there against, thereby
removing foreign material including toner from the surface of the
plate when in its position of close adjacency thereto. The magnet
and armature assembly 41 is actuated to drive the actuable cleaning
member against the plate and the spring 43 returns the cleaning
member to a position of nonadjacency to the plate when the magnet
and armature assembly is deactuated. When in its position of
nonadjacency to the plate, the actuable cleaning member 19 does not
contact the surface of the plate, and therefore, the plate rotates
therepast without interference therefrom.
The actuable charging station 21 comprises three corona generating
wires 47, 48, and 49 which are sequentially turned on and off as
the interframe gaps of the electrostatic plate 11 rotate therepast.
For example, when the actuable charging station is turning on, the
corona generating wire 47 is first energized as the first portion
of an interframe gap rotates therepast. The corona generating wire
48 is then turned on as the same leading edge portion of the
interframe gap rotates therepast, and thereafter, the corona
generating wire 49 turns on as the leading edge portion of the
interframe gap rotates therepast. Thus, any discontinuities in
charge levels effected by turning on the corona generating wires
appear within the interframe gap portions of the electrostatic
plate 11. The same magnetic signal which is sensed by the sensing
device 13 may also be utilized to actuate magnetically actuable
switches to effect the sequential turn on and turn off of the
corona generating wires 47, 48 and 49. The turn off sequence of the
actuable charging station is identical to the turn on sequence.
The imaging station 23 comprises a fixed transparent document
mounting means 55 onto which the master 25 to be copied is placed.
A moving optical projection system 33 projects a progressive light
image of the master 25 through the stationary lens 56 and aperture
member 57 onto the electrostatic plate 11 rotating therepast. The
moving optical projection system 33 includes a first carriage 59
and a second carriage 61, both mounted in telescopic fashion on a
common track means 63 for reciprocal movement. The first carriage
59 supports a parabolic reflector 65 which cooperates with a
stationary paraboloid reflector 67 to direct light from a lamp 69
upon an original document 25 through document mounting means 55 to
thereby illuminate a segmental portion of the master 25. Lamp 69
has an associated reflector 68 for intensifying and directing light
toward reflector 67. The arrangement is such that a moving line of
light is projected onto document 25 during scanning. A scanning
mirror 71 is also mounted on the first carriage 59 for receiving
the image of the master thus illuminated.
The second carriage 61 supports a pair of compensating mirrors 73
and 75 which receive the image as reflected by the scanning mirror
71 and redirect the image to stationary mirror 77 through lens 56
from whence the image is reflected through the stationary aperture
member 57 onto the moving electrostatic plate 11. The first
carriage 59 and the second carriage 61 are mechanically
interconnected through a closed loop flexible cable 79 to cause the
movement of the second carriage 61 to be one-half of that of the
first carriage 59. By thusly moving the second carriage 61 by an
amount equal to one-half the distance moved by the first carriage
59, a constant optical path from the document mounting means 55
through the mirrors 71, 73, and 75 to the lens 56, mirror 77 to the
electrostatic plate 11 is maintained during the motion of the first
carriage 59, and the second carriage 61 in the scanning direction
of arrow 81. The flexible cable 79 is mounted on rollers 83 and 85
carried by the second carriage 61. A ground clamp 87 makes one
point on the flexible cable 79 stationary at all times. The first
carriage 59 is connected to an intermediate point of the cable 79
at point 89.
The motion in the scanning direction of arrow 81 is imparted to the
first carriage 59 by the actuable drive motor 91 which is connected
to the capstan 93 which is in turn connected to the cable system
95. As described heretofore, motion of the first carriage 59 in the
direction of arrow 81 effects motion of the second carriage 61
through the flexible cable 79 so that the second carriage moves
one-half the distance of movement of the first carriage. Upon
completion of motion in the scanning direction of arrow 81, the
first carriage 59 and the second carriage 61 are returned to their
initial home positions by the spring motor 97 which effects
rotation of the capstan 93 in an opposite direction thereby causing
the cable system 95 to move the first carriage 59 in the direction
of arrow 99. The second carriage 61 is returned by the action of
member 60 of the first carriage 59 pulling the member 61a of the
carriage 61 to its home position.
Summarizing, the scanning mirror 71 and an illumination system
including lamp 69 and reflector 65 are driven by the capstan 93 in
synchronism with the rotation of the electrostatic plate 11. As the
scanning mirror 71 approaches the compensating mirror 73 thus
tending to shorten the optical path, the compensating mirror 73
retreates at one-half the speed of the scanning mirror 71.
Additionally, the compensating mirror 75 also moves with the
compensating mirror 73 thereby creating a folded optical path which
compensates for the tendency to shorten the optical path and
maintains a constant optical path during the scanning operation.
Accordingly, a light image of the master 25 is progressively
projected onto a frame of the electrostatic plate 11 rotating past
the aperture 57 creating a latent electrostatic image thereon. Once
a complete frame section has been exposed, the lamp 65 is turned
off and the first carriage 59 and the second carriage 61 are then
driven to their home position under the control of the cable system
95. During the time that the optical system is returning and
awaiting a new scan cycle, the next frame of the electrostatic
plate 11 rotates past the perture 57.
As the electrostatic plate 11 passes the developer station 27,
electrostatically charged toner is applied thereto thereby
developing the latent electrostatic image existing on the surface
of the electrostatic plate 11.
The operation of the developer station 27 is generally described in
the aforereferenced copending application of Allison H. Caudill.
The developer station includes a sump portion 111 containing
multicomponent developer material 33. The principle components of
the developer material are electroscopic toner and a carrier
material. Suitable materials for use as toners are well known in
the art and generally comprise finely divided resinous materials
capable of being attracted and held by electrical charges. Many
well-known suitable carrier materials can be utilized, the carrier
particles generally being between 50 and 1,000 microns in size. The
carrier materials which are utilized for the developer station
depicted must be ferromagnetic or capable of being attracted and
held by a magnetic field. Such a carrier material could comprise a
magnetic bead coated with a material which triboelectrically
interacts with the selected toner to produce a desired charge on
the toner in order to provide good imaging quality.
A toner dispensing unit 115 is provided to dispense toner particles
117 into the multicomponent developer material 113 located in the
sump portion 111 of the developer station 27. Counter-rotating
augers 119 and 121 stir the freshly added toner with developer
material to assure complete mixing thereof.
A bucket conveyor 123 rotates through the sump portion 111 of the
developer station 27 and scoops up quantities of developer material
113 for delivery to the magnetic brush unit 125. The magnetic brush
unit includes a conductive, nonmagnetic, rotatable, cylindrical
member 127 having located therein a magnetic field producing means
129. Since the core material of the carrier particles consists of a
ferromagnetic material the carrier particles are caused to be
magnetically attracted to the surface of the cylindrical member 127
and held thereon by magnetic forces produced by the magnetic field
producing means 129. The cylindrical member 127 rotates in the
direction of arrow 131 under a doctor blade 133 which governs the
amount of developer material located on the surfaces of the
cylindrical member 127 as it rotates to a position adjacent the
electrostatic plate 11. As described in the aforereferenced
copending application of Allison H. Caudill, the magnetic field
producing means 129 creates a normal magnetic field at
approximately the 9 o'clock position of the cylindrical member 127
causing the magnetic carrier particles in the developer material
113 to form in bristle-like arrays emanating from the surface of
the cylindrical member 127.
The small toner particles of the developer material 113 are held
onto the surface of the relatively large carrier particles by
electrostatic forces, which develop from the contact between the
toner and the outer surface of the carrier particles which produces
triboelectric charging of the toner and carrier material to
opposite polarities. A potential source (not shown) is connected to
the cylindrical member 127 thereby biasing the cylindrical member
to a fixed potential. As the magnetically formed bristles of
carrier material containing toner triboelectrically attracted
thereto rotate past and in contact with the electrostatic plate 11,
the triboelectrically charged toner particles are attracted to the
electrostatic latent image on the plate 11 and adhere thereto. The
potential on the cylindrical member correctly orients the
electrical field in which the charged toner particles move to
produce a uniformly developed image on the surface of the plate 11.
The electrostatic plate 11 containing a toned or developed image
continues its rotational movement past the developer station 27 and
continues to the transfer station 31. The carrier particles and the
unspent toner particles attracted thereto are retained on the
surface of the cylindrical member 127 until it reaches its
approximage 6 o'clock position whereupon they are released into the
sump portion 111 for subsequent mixing and reuse.
As the developed image on the electrostatic plate 11 moves from the
developer station 27 toward the transfer station 31, a substrate
surface such as paper is fed from the hopper 141 by the picker roll
143 which is actuated in timed relation to the rotational movement
of the electrostatic plate 11.
The substrate surface 29 is fed over a feed path to the transfer
roller 145. The transfer roller comprises a conductive core 147 and
a dielectric outer layer 149. The conductive roll is biased so that
the positively charged toner particles will separate from the
electrostatic plate 11 and transfer to the support substrate 29.
That is, an electric field is created between the grounded
conductive backing member of the electrostatic plate 11 and the
biased core 147 through the photoconductive surface of the
electrostatic plate 11 and the insulating material 149 of the
transfer roller 145. The toner particles move within this field to
the support substrate 29 located between the electrostatic plate 11
and the transfer roller 145. Thereafter, the support substrate is
removed from the surface of the electrostatic plate 11 by the
pickoff means 151. The pickoff means 151 can comprise any of the
well-known pickoff devices utilized in the duplicator art such as
timed air puffs, stationary guide members, or movable guide
members. The thusly separated substrate surface 29 containing a
toned image is thereafter transported to a fuser station (not
shown) where the toner is fused to the substrate in a well-known
manner.
The description immediately preceding has related to the operation
of each of the processing stations located about the rotating
electrostatic plate 11. As described heretofore, various ones of
these stations are sequentially actuated in accordance with the
positional rotational relationship of the electrostatic plate 11
with respect to the fixed sensing device 13. The sequential
actuation of the various stations facilities alternate imaging and
redevelopment cycles. By utilizing such alternate imaging and
redevelopment cycles, the throughput speed of the reproduction
apparatus is increased since there is no longer a requisite delay
time occasioned by the moving optical projection system 33 which
must reset to an initial condition. Further, by limiting the number
of redevelopment cycles, high quality output images are
maintained.
When utilizing an electrostatic plate having three segments such as
that depicted in FIG. 1 of the drawings, alternate segments are
first imaged on the first rotation of the electrostatic plate and
the electrostatic latent images created thereby are not thereafter
substantially altered, thus allowing the latent image to be
redeveloped on the second revolution of the electrostatic plate.
The cleaning member and the charging station are actuated prior to
imaging cycles and deactuated prior to redevelopment cycles. The
following table summarizes a suggested cyclic operation of the
cleaning, charging, imaging, and transfer stations.
---------------------------------------------------------------------------
TABLE I
Plate Rev. Frame Clean Charge Image Transfer
__________________________________________________________________________
A Yes Yes Scan Yes (image) 1 B Yes No Return No (no image) C Yes
Yes Scan Yes (image)
__________________________________________________________________________
A No No Return Yes (no image) 2 B Yes Yes Scan Yes (image) C No No
Return Yes (no image)
__________________________________________________________________________
A Yes Same as Same as Yes 3 B No Rev. 1 Rev. 1 Yes C Yes Yes
__________________________________________________________________________
A Same as Same as Same as Same as 4 B Rev. 2 Rev. 2 Rev. 2 Rev. 2 C
__________________________________________________________________________
as can be seen from Table I, the operation on all even numbered
plate revolutions is the same. After the first plate revolution,
the operation of the device is the same for all odd-numbered plate
revolutions, the only difference between plate revolutions 1 and 3
being the operation of the cleaning and transfer stations with
respect to the B segment which does not go through a redevelopment
cycle on the first plate revolution.
Referring once again to FIG. 1 of the drawings, the machine logic
which effects the cyclic operation of the cleaning, charging,
imaging and transfer stations is depicted in block form. The
reproduction apparatus is started upon operator depression of a
start control 161. The operator also sets a copy counter 163
indicating the number of reproductions of the master 25 which are
desired. Assuming that a number of copies is specified, the copy
counter 163 provides an output signal to the And gate 165 which
provides a machine on signal. The machine on signal initiates the
rotational movement of the electrostatic plate 11 in the direction
of arrow 15 and initiates the various processing stations in a
well-known manner (e.g., the bucket conveyor 123 is rotated). When
the indicia located in the interframe gap, a, of the rotating
electrostatic plate 11 is sensed by the sensing device 13, the
frame counter 167 provides an output signal to the And gate 169
which in turn, sets latch 171. The frame counter 167 also provides
an output signal to the Or gate 173 upon sensing the indicia
located in the interframe gaps a, b, and c as they rotate past the
sensing device 13. The output signal of the Or gate 173 and of the
latch 171 are provided to the And gate 175 which, in turn, provides
a signal to the copy counter 163 causing that counter to be
decremented. Thus, the copy counter is decremented as each segment
rotates past the sensing device 13. It should be noted that the
copy counter is initially set with a number which exceeds the
number specified by the operator by four. This is to insure that
the first rotational pass of segment B, which produces no copy, is
not counted and that the last counted segment rotates fully around
to the transfer position. Thus, when the copy counter reaches a
count of zero, the requisite number of copies have been reproduced
and the machine is cycled off. It should further be noted that the
output signal of the copy counter is utilized to prevent charging
and scanning during the runout of the last copy.
The frame counter 167 also provides an output to the plate
revolution counter 179 each time the interframe segment, a, passes
the sensing device 13. The plate revolution counter provides an
output signal indicating whether the electrostatic plate is in its
first revolution past the sensing device 13 and, thereafter,
whether the plate is in an even or odd-numbered revolution. The
output signals of the plate revolution counter 179 and of the frame
counter 167 are applied to the And gates 180-183 which, in turn,
are applied to the Or gates 187 and 188 and the inverter 189. The
output signal of the Or gate 187 is applied to the cleaning control
192. The cleaning control 192 is further provided with an input
signal (not shown) indicating the precise rotational relationship
of the electrostatic plate 11 with respect to the cleaning station
17. As a segment of the plate to be cleaned rotates past the
actuable cleaning member 19, cleaning control 192 provides a signal
to the magnet and armature assembly 41 causing the cleaning member
to contact the electrostatic plate 11. The signal remains on until
the entire segment has passed the cleaning member at which time the
output signal of the cleaning control 192 is removed.
In a similar manner, the output signal of the Or gate 188 is
provided to the charge control 194 which is also supplied with a
timing signal (not shown) indicating the exact positional
relationship of the interframe segment with espect to the actuable
charging station 21. The charge control provides an output signal
which effects the turn on or turn off of the corona generating
wires 47, 48, 49 as the interframe segment rotates therepast.
The output signal of the Or gate 188 is also provided to the scan
and illuminate control 196. This control is also provided with a
timing signal indicating the exact positional relationship of the
rotating electrostatic plate past the imaging station 23. The
output signal of this device is supplied to the drive motor 91
which effects movement of the moving optical system in the scanning
direction of arrow 81. Additionally, the output signal of the scan
and illuminate control turns on the lamp 69 thereby illuminating
the master 25. At the completion of a scan, the output signal of
the scan and illuminate control is dropped, thereby causing the
lamp 69 to be extinguished and the enabling signal to be removed
from the drive motor 91. The spring motor 97 effects the return of
the moving optical projection system 33 in the direction of arrow
99.
The inverter 189 provides an output signal to the transfer control
198 which is also provided with a signal indicating the positional
relationship of the electrostatic plate 11 with respect to the
transfer station 31. The output signal of the transfer control 198
effects the rotational operation of the picker roller 143, thereby
causing a substrate surface 29 to be fed from the hopper 141 in
timed relationship to the arrival of a developed image at the
transfer station 31.
As described heretofore, the copy counter 163 provides a signal to
the charge control 192 and to the scan and illuminate control 194
preventing, respectively, the charging and scanning of unwanted
segments during a runout cycle. The same signal is provided to the
cleaning control 192 which effects cleaning of those segments which
rotate past the cleaning station during a runout cycle.
It should be noted that the timing signals indicating the exact
positional relationship of the electrostatic plate 11 with respect
to the various stations supplied to the cleaning control 192, the
charge control 194, the scan and illuminate control 196, and the
transfer control 198 may be provided by sensing devices similar to
the sensing device 13 located at each station or by logic
responsive to the sensing device 13 or by mechanical logic (e.g.,
cams, etc.) well known in the art. Further, the output signal of
the cleaning control 192 may be held on through an appropriate
electronic delay device or by a mechanical delay. Additionally, the
charge control is depicted as being responsive to logic which turns
on the actuable charging station 21. It should be noted that the
absence of a signal from the Or gate 188 effects the turn off of
the actuable charging station as an appropriate interframe segment
passes thereunder.
ILLUMINATION SYSTEMS
The arrangement of the illumination elements in all three versions
of the present invention is such that a line of light is projected
toward an original document, or object, the line of light having a
predetermined finite length confined within a light zone not
normally encountered by an operator of the equipment. The
principles may best understood by reference to the detailed
drawings 2a-5b.
FIRST VERSION
In the first version, a stationary paraboloid reflector element 67
receives light from lamp 69, projects the same toward parabolic
reflector 65 which in turn reflects the light toward the original
document. The two reflector elements 65 and 67 cooperate in such a
manner that a line of light of finite width and length is obtained.
The typical tracings of light from source 69 are shown in FIG. 2a.
The light is projected toward paraboloid reflector 67 that serves
to collimate the light as it is directed toward parabolic reflector
65. Parabolic reflector 65 in turn, is designed with a focal line
that produces a line of light of predetermined width in area 25a of
document 25. Further understanding of the first version may be had
by reference to FIGS. 3a, 3b, and 3c representing a top elevation,
side elevation, and partial end elevation of an illumination scheme
similar to that shown in FIG. 1 but differing in a number of
aspects. Where appropriate, identical reference numerals are used
in FIGS. 3a-3c that correspond, respectively, with numerals in FIG.
1. When illumination of a document is required, lamp 69 is
energized and light is projected toward paraboloid reflector 67a
that is stationarily mounted in the apparatus. Spherical reflector
68, which has a reflective inner surface, serves to prevent direct
light emanating from lamp 69 from going into the light zone, and
also improves the efficiency of the system by re-directing light
back toward lamp 69. The reflector 67a serves not only to collimate
the light within predetermined vertical dimensons as shown in FIG.
2a as it is projected toward reflector 65, but further collimates
the light from lamp 69 so that it remains substantially within the
light zone in a horizontal plane, particularly shown in FIG. 3a.
Thus, the shape of paraboloid reflector 67a is such that collimated
light is produced in a two-dimensional sense, that is both
vertically and horizontally. The dimensions of the arrangement are
such that a relatively uniform level of illumination is maintained
throughout the scanning range of movement of parabolic reflector
65, or 65a, as the case may be. As previously discussed in
connection with FIG. 1, reflector 65 is mounted for travelling
movement on carriage 59, more specifically designated as members
59a and 59b in FIG. 3a. Only so much of the driving and travelling
mechanisms of FIG. 1 as are believed necessary for an understanding
of the illumination system are shown in FIGS. 3a-3c.
The two-dimensional collimated light projected from reflector 67a,
FIG. 3a, travels toward parabolic reflector 65a, throughout its
range of movement. As shown in FIG. 3a, reflector 65a is in the
home position and from such position travels toward the right
within the bounds of frame number 62. As previously indicated in
connection with FIG. 1, this is effected by sliding reciprocating
movement of bearing members 59a and 59b on rods 63a and 63b,
respectively. Also, as described in FIG. 1, the movement is
evidenced by arrows 81 and 99.
While many of the elements shown in FIGS. 3a-3c are similar to
those in FIG. 1, some differences exist. As an example, in FIGS.
3a-3c, carriage member 59b has an extension 59c extending into the
path of movement of a drive belt 79a. Drive belt 79a is mounted on
pulleys 82 and 84 for reciprocating movement as pulleys 82 and 84
are rotated. Ordinarily, a drive means, not shown, is connected to
one of the pulleys 82 or 84 to rotate the same and drive belt 79a
in a reciprocating fashion, evidenced by arrows 81 and 99. Belt 79a
is provided with regularly spaced driving teeth, best seen in FIG.
3b, that engage correspondingly shaped segments on a clamp element
86. Clamp element is firmly interconnected to extension 59c with a
portion of belt 79a passing therebetween through a screw connection
88. Due to the connections just described, reciprocating motion of
reflector member 65a is effected.
It is evident that the arrangement of the first version, as well as
others to be described, provides a highly efficient illumination
system wherein light from a light source is controlled to produce a
line of light having a finite width and finite length. If it is
assumed that the top elevation of FIG. 3a conforms to the original
document supporting area of a copy machine, it is readily
understood that an operator while using the machine, would be
standing under normal circumstances in a position that is on one or
the other side of the light zone indicated in FIG. 3a. This being
the case, the operator ordinarily sees no light emanating from the
zone and glare is thereby eliminated. If per chance, as during
testing procedures, the illumination system is operated and
reflector element 65a reciprocated as indicated by arrows 81 and 99
with no original document in place and an associated document
cover, not shown, out of the way, the operator would see only low
intensity scattered light as scanning takes place.
SECOND VERSION
FIG. 2b illustrates a second version of the illumination system
wherein the parabolic reflector 65 is replaced by a pair of
parabolic reflectors 64 and 66. Reflectors 64 and 66 receive
collimated light from paraboloid reflector 67 but as can be
observed in FIG. 2b, reflector 66 receives the upper portion of the
collimated light while reflector 64 receives the lower portion of
the collimated light. The positional relationships and preselected
curvatures and angles of reflectors 64 and 66 are such that the
collimated light is re-directed through document glass 55 to
original document 25 and confined in an area 25b on document 25.
The arrangment is such that better light distribution of a
three-dimensional object in the area 25b can be achieved in this
manner. In this case, it is understood that document 25 is
representative of a three-dimensional object.
TYPICAL PRIOR ILLUMINATION SYSTEM
To further illustrate the advance represented by the present
inventive arrangements, a prior illumination arrangement is
illustrated in FIG. 4. This includes a reflector member 92 lamp 94
and filament shield 96. The direction of scan is also indicated.
Although there is a filament shield 96 that prevents a direct path
for light to project from the filament to the eye of an operator,
the reflector 92 establishes a multude of paths that are reduced in
intensity only slightly, such as by one reflection loss level.
Attempts to shield this kind of reflected light severely reduces
the net illumination to a document or requires greater power to the
lamp to achieve sufficient illumination.
THIRD VERSION
The problems encountered with the prior illumination arrangement of
FIG. 5 are readily eliminated by use of the illumination
arrangements taugh herein, including the first and second versions.
They may also be eliminated by use of the third version illustrated
in FIGS. 5a and 5b. In this case, a compact source of light 102
cooperates with a shield 104 and a specially shaped reflector 106
to produce the line of light or light footprint shown on the line
108 having a finite width and finite length. The special
characteristics of the reflector 106 are that it has a curvature
that is parabolic when viewed in the scan direction indicated in
FIG. 5a. The configuration of reflector 106 in a direction
transverse to the scan direction is substantially elliptical. It is
noted that substantially elliptical curvatures need not be
maintained in this plane. That is this curvature could be
straightened out more and made essentially flat, but whatever the
shape of the reflector 106 in this plane, no light goes in the
operator's eyes. A substantially elliptical curvature is desired
however to produce a narrow light. Any light going toward the
reflector 106 is directed straight up to the footprint area on line
108 with light not going toward reflector 106 being intercepted by
shield 104. This light is either absorbed or reflected back toward
the source 102. The side view of reflector 106 is shown in FIG. 5b
as it might be incorporated in a copier.
Advantages of this version, as well as the others include the fact
that all light emanating from the illumination system is radiated
in a perpendicular fashion with respect to the scan direction and
no light is radiated obliquely toward an operator or someone else
standing at the side of a machine. With respect to the third
version in FIGS. 5a and 5b, as well as the other versions, a
compact source of light is advantageous since this permits the use
of high-intensity discharge lamps or the more efficient projector
type of lamp, such as a tungsten lamp. This also permits easier
focusing since only one compact light source need be positioned. By
proper variation of the width of the reflector, the light intensity
may be controlled to any desired distribution, for example, in
order to compensate for the Cosine Fourth Power Law diminution of
light in the system. Also, for versions one and two, a specially
contoured mask may be positioned in the path of the collimated beam
of light from reflector 67 to 65. The characteristic of the
reflectors in all versions enables the establishment of a narrow
line of light without using apertures. The systems described herein
may be positioned in any direction of scan relative to the
operator, and still keep light from the eyes of the operator. As an
example, this would apply to someone standing at the side of a
front to back scanning machine. It is noted that the reflector
elements may be formed of heat transmitting material thereby
keeping heat off of the document area. In addition, the spectral
characteristics of the light going to the document may be tailored
to the specific requirements of the application.
While the invention has been particularly shown and described with
reference to a number of embodiments thereof, it should be
understood by those skilled in the art that various changes in form
and detail may be made without departing from the spirit and scope
of the invention.
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