Fiber lens array mounting in reproduction machines

A reproduction machine employing a gradient index fiber lens array having a mounting pin adjacent each end of the array body, a flat metallic array support surface in the machine against which the array abuts when in place in the machine, a mounting hole in the array support surface opposite each of the array mounting pins, the array mounting pins fitting snugly into the array mounting holes on assembly of the array with the support surface, and a pair of strip magnets on the side of the array facing the support surface for attracting and holding the array tightly against the support surface.

The invention relates to a reproduction machine employing a lens array, and 
more particularly, to a relatively simple and inexpensive lens array 
mounting which facilitates insertion and removal of the lens array while 
maintaining critical optical alignments. 
In reproduction machines, a document to be copied is typically supported on 
a platen and means provided to effect scanning movement between the 
document and the machine recording member. The latter may for example 
comprise the photoreceptor of a xerographic type system. In that type of 
system, the photoreceptor is first charged in preparation for imaging and 
thereafter exposed at an exposure station to image rays of the document 
image. The image rays discharge the previously charged photoreceptor to 
form a latent electrostatic image of the document on the photoreceptor. 
The image on the photoreceptor is later developed and the developed image 
transferred to a copy substrate material such as a copy sheet brought 
forward in timed relation with the developed image. The copy sheet with 
the developed image transferred thereto is thereafter fused or fixed while 
the photoreceptor is cleaned preparatory to charging. 
To focus and transmit the image rays to the photoreceptor at the exposure 
station, an optical system is normally employed. Recently, an array of 
gradient index fiber lenses or Selfoc lens array has been used for this 
purpose. Selfoc is a registered Trademark of Nippon Sheet Glass Company, 
Japan. The lens array, which normally extends the width of the platen is 
placed between platen and exposure station with the optical axis of the 
lens array coincident with the axis between the scanning point on the 
platen and the exposure station. 
However, because of the incidence of dirt, dust, etc. in and about the 
machine, it is often necessary to clean or wipe the lens array. While 
cleaning can sometimes be done with the lens array in place in the 
machine, for best results it is usually necessary to remove the array. 
However, this is often a difficult chore requiring a trained technician or 
operator and special tools. And since the optical alignment of the lens 
array is critical to successful operation of the machine, re-inserting the 
lens array is difficult and time consuming if the lens array is to be 
accurately aligned and damage or scratching of the array avoided. 
To alleviate this problem and provide a lens array mounting that is simple 
and inexpensive yet at the same time allows ready removal and installation 
of a lens array in a reproduction machine with assured optical alignment, 
the present invention provide, in a reproduction machine having a lens 
array for transmitting image rays of the document lines scanned along an 
optical path to a photoreceptor to expose the photoreceptor and create a 
latent electrostatic image of the document, the lens array having a 
generally rectangular body with at least one substantially planar side and 
a plurality of lenses arranged in at least one row, the row of lenses 
being substantially parallel with the scan line; the combination of: at 
least two discrete lens aligning points on the array body for use in 
locating the lens array in the machine and aligning the lens array in the 
optical path; a substantially planar lens support and locating surface in 
the machine between the scan station and the photoreceptor, the lens 
support surface being in a plane substantially parallel to but offset from 
the scan line; a locating point on the lens support surface for each of 
the lens aligning points on the array body, the lens aligning points on 
the array body and the locating points on the lens support surface 
interengaging with one another on bringing the array body into side by 
side abutting relation with the lens support surface to locate and align 
the lens array in the machine; and magnetic means for releasably securing 
the array body tightly against the lens support surface.

Referring to FIG. 1 of the drawings, there is shown a xerographic type 
reproduction machine 8 incorporating the present invention. Machine 8 has 
a suitable frame 12 on which the machine xerographic components are 
operatively supported. 
Briefly, and as will be familiar to those skilled in the art, the machine 
xerographic components include a recording member, shown here in the form 
of a rotatable photoreceptor 14. In the exemplary arrangement shown, 
photoreceptor 14 comprises a drum having a photoconductive surface 16. 
Other photoreceptor types such as belt, web, etc. may instead be 
contemplated. Operatively disposed about the periphery of photoreceptor 14 
are charge station 18 with charge corotron 19 for placing a uniform charge 
on the photoconductive surface 16 of photoreceptor 14, exposure station 22 
where the previously charged photoconductive surface 16 is exposed to 
image rays of the document 9 being copied or reproduced, development 
station 24 where the latent electrostatic image created on photoconductive 
surface 16 is developed by toner, transfer station 28 with transfer 
corotrons 29, 30 for transferring the developed image to a suitable copy 
substrate material such as a copy sheet 32 brought forward in timed 
relation with the developed image on photoconductive surface 16, and 
cleaning station 34 with cleaning blade 35 and discharge corotron 36 for 
removing leftover developer from photoconductive surface 16 and 
neutralizing residual charges thereon. 
Copy sheets 32 are brought forward to transfer station 28 by feed roll pair 
40, sheet guides 42, 43 serving to guide the sheet through an 
approximately 180 turn prior to transfer station 28. Following transfer, 
the sheet 28 is carried forward to a fusing station 48 where the toner 
image is fixed by fusing roll 49. Fusing roll 49 is heated by a suitable 
heater such as lamp 47 disposed within the interior of roll 49. After 
fixing, the copy sheet 32 is discharged. 
A transparent platen 50 supports the document 9 as the document is moved 
past a scan point 52 by a constant velocity type transport 54. As will be 
understood, scan point 52 is in effect a scan line extending across the 
width of platen 50 at a desired point along platen 50 where the document 
is scanned line by line as the document is moved along platen 50 by 
transport 54. Transport 54 has input and output document feed roll pairs 
55,56 respectively on each side of scan point 52 for moving document 9 
across platen 50 at a predetermined speed. Exposure lamp 58 is provided to 
illuminate a strip-like area of platen 50 at scan point 52. The image rays 
from the document line scanned are transmitted by a gradient index fiber 
lens array 60 to exposure station 22 to expose the photoconductive surface 
16 of the moving photoreceptor 14. 
Developing station 24 includes a developer housing 65, the lower part of 
which forms a sump 66 for holding a quantity of developer 67. As will be 
understood by those skilled in the art, developer 67 comprises a mixture 
of larger carrier particles and smaller toner or ink particles. A 
rotatable magnetic brush developer roll 70 is disposed in predetermined 
operative relation to the photoconductive surface 16 in developer housing 
65, roll 70 serving to bring developer from sump 66 into developing 
relation with photoreceptor 14 to develop the latent electrostatic images 
formed on the photoconductive surface 16. 
Referring particularly to FIG. 2, lens array 60 has an elongated generally 
rectangular body 80 with flat sides 87, 88 and a plurality of fiber lens 
elements 83 arranged in two linear arrays or rows 84, 84' extending from a 
point adjacent one end 81 of the array body 80 to a point adjacent the 
opposite end 82. The individual lens elements 83 of each row 84, 84' are 
staggered or offset with respect to one another with the effective length 
of rows 84, 84' being substantially equal to or slightly greater than the 
largest document to be copied. While two rows 84, 84' of fiber lens 
elements 83 are shown, a single row of lens elements may be contemplated. 
Alternately, the number of rows of lens elements may be greater than two 
and in any multiple row arrangement, the lens elements may be aligned or 
staggered with respect to one another. 
As will be understood, lens array 60 is mounted in machine 8 in alignment 
with the optical axis between scan point 52 on platen 50 and exposure 
station 22 to assure that the individual fiber lens elements 83 focus and 
transmit images of the entire area of the document line at scan point 52 
to the photoconductive surface 16 without image loss or distortion. 
To support lens array 60 in machine 8 while at the same time accurately 
establishing and maintaining critical optical alignment of the lens array 
60, frame 12 of machine 8 includes a fixed array support or locating 
surface 85 between platen 50 and exposure station 22. Support surface 85, 
which is substantially flat or planar, is in a substantially vertical 
plane parallel to the longitudinal axis of scan point 52 but offset 
slightly therefrom to accommodate the thickness of the array body 81 and 
the array attaching means as will appear. 
As will be understood by those familiar with gradient index fiber lens 
arrays, during manufacture of the lens array, there is typically provided 
a pair of locating holes 90, 91 adjacent each end 81,82 of the array 
member 81. Locating holes 90,91 serve as points of reference during 
manufacture of the lens array and hence provide extremely accurate 
reference points for installing and locating the lens array during 
subsequent use. 
A pair of array mounting pins 92, 93 are inserted into holes 90, 91 
respectively of the array body 80 and secured. Pins 92, 93 project 
outwardly from side 87 of the array body 80. A pair of mounting holes 94, 
95 are provided in support surface 85 for mating engagement with mounting 
pins 92, 93 respectively on the array body 80. The position, size, and 
shape of array mounting holes 94, 95 are chosen to assure that pins 92, 93 
on the array body 80 tightly and snugly fit within mounting holes 94, 95 
respectively in support surface 85 on assembly of array member 80 with 
support surface 85. 
To attach and hold the array body 80 tightly against support surface 85 
along the length thereof with mounting pins 92, 93 in mounting holes 94, 
95 respectively, a pair of strip magnets 101, 102 are provided on side 87 
of the array body 80 opposite support surface 85 adjacent each end 81, 82 
of member 80. Strip magnets 101, 102 may be attached to side 87 of array 
member 80 by any suitable means, as for example by adhesive. Strip magnets 
101, 102 have an axial length chosen to provide the requisite degree of 
magnetic force necessary to attract and hold the array body 80 tightly and 
securely against support surface 85 while permitting lens array 60 to be 
readily and easily removed and replaced while maintaining optical 
alignment of the array fiber lens elements 83 with the machine optical 
axis. To provide support and prevent bending or arching of the array body 
in the area between strip magnets 101, 102 and additionally absorb 
vibrations, a strip of relatively rigid foam material 105 is fastened to 
side 87 of array member 80 between strip magnets 101, 102. The compressed 
thickness of foam material 105, which may be fastened to side 87 of array 
member 80 by any suitable means such as adhesive, is substantially the 
same as that of strip magnets 101, 102. 
While a pair of strip magnets 101, 102 are shown, a single strip magnet 
extending the length of the array body may instead by used. Alternately, a 
succession of smaller strip magnets may be attached in spaced relation to 
one another on side 87 of array body 80 with or without strips of foam 
material therebetween. And while the intermediate strip 105 is described 
as being composed of a suitable foam material, other relatively rigid 
non-magnetic materials may instead be contemplated. 
While mounting pins 92, 93 and mounting holes 94, 95 are shown and 
described as being on the array body 80 and machine support surface 85 
respectively, the position may be reversed with pins 92, 93 mounted on and 
projecting from support surface 85. In that event, locating holes 90, 91 
in the array body 80 would normally be used as mounting holes for the 
receipt of mounting pins 92, 93 respectively. Additional mounting holes 
and pin pairs may also be envisioned. 
While the invention has been described with reference to the structure 
disclosed, it is not confined to the details set forth, but is intended to 
cover such modifications or changes as may come within the scope of the 
following claims.