Apparatus for semiautomatic inspection of microfilmed documents for density, resolution, size, and positio

Klein, E. L.

English

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APPARATUS FOR INSPECTING MICROFILM 
Filed May 16, 1969 2 Sheets-Sheet 2 
INVENTOR 
EUGENE L. KLEIN 
ATTORNEYS 
A microfilm inspection apparatus having reels for trans- 
porting microfilm over a light box and a rather large 
magnifying glass for viewing the film for general defects 
as its moves over the light box. The apparatus has a 
microscope adjacent the magnifying glass to  obtain de- 
tail inspeetion of any particular frame of the film. Also, 
an electrical densitometer is pivotally mounted so as to 
swing into contact with the film and thereby obtain an 
accurate determination of the film density. 
ORIGIN O F  THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National Aero- 
nautics and Space Act of 1958, Public Law 85-568 (72 
Stat. 435; 42 U.S.C. 2457). 
FIELD O F  THE INVENTION 
The present invention relates to an inspection appara- 
tus for film and more specifically to an apparatus for semi- 
automatic inspection of microfilmed documents to in- 
sure the proper standards of density, resolution, size and 
position. 
DESCRIPTION O F  THE PRIOR ART 
Microfilm has been widely adopted as a standard for 
recording engineering drawings. It is normally necessary 
that the hundreds of thousands of microfilmed images of 
drawings be inspected to assure proper image size and 
position tolerances, resolution requirements, and density 
restrictions. 
Herebefore, microfilm inspection has normally been 
accomplished manually using an individual microscope, 
a densitometer, a light box, and hand-cranked wheels. 
This method of inspection is time consuming, and in- 
volves the subjective judgment of the inspector. 
SUMMARY O F  THE INVENTION 
In the present invention, a single apparatus is pro- 
vided which functionally brings together a microscope, 
densitometer, light box, and automatic film transport 
system to achieve an integrated microfilm inspection ap- 
paratus. The apparatus has a main housing supporting 
a motorized forward winding reel and a motorized re- 
verse winding reel for transporting the film. A light box 
is secured to one side of the housing and idler reels 
guide the film from the forward and reversed winding 
reels across its lighted surface. A large magnifying glass 
is supported in front of the light box so as to view the 
moving film, and a microscope is pivotally mounted rela- 
tive to the light box whereby any individual image may 
be viewed to determine the resolution of the lines. Also, 
a densitometer is pivotally associated with the light box 
to obtain film density readings. The densitometer may 
be electrically connected so as to obtain a direct reading 
on a meter attached to the front of the housing as well 
as lights to indicate proper tolerance limits. 
Accordingly, it is an object of the present invention 
to provide an apparatus for easily inspecting the image 
quality of microfilm. 
Another object is to provide an apparatus which is 
compact in design and readily allows the microfilm to 
be inspected without damage. 
Other objects and advantages of the present invention 
will become more apparent from the following detailed 
description when taken in conjunction with the accom- 
panying drawings. 
BRIEF DESCRIPTION O F  THE DRAWINGS 
FIG. 1 is a side view of the apparatus according to 
the present invention, partly in section and portions re- 
moved for clarity; 
FIG. 2 is a front view of the apparatus; 
F'IG. 3 is a front view of the apparatus with the front 
10 
15 
panel swung open. 
DESCRIPTION O F  THE PREFERRED 
EMBODIMENT 
Referring to the drawings there is shown in FIGS. 1 
and 2 an apparatus 11 for inspecting the images on a 
roll of microfilm 13. The apparatus 1 
tially of a main housing 15 having a side mounted light 
25 box 21 with a magnifying glass 23, a microscope 25, 
and a densitometer 27 for inspecting the film 13 trans- 
ported across the light box 21 by motor driven reels 29 
and 30, and also having therein (see FIG. 3 )  motors 17 
and 18 and electrical wiring 19. 
The main housing 15 has an inwardly slanting front 
panel 31 extending from a horizontal base 33 and a 
vertical back panel 35 and two vertical side panels 37 
and 38. The top panel 40 slopes downwardly slightly 
from the front to eliminate unnecessary weight and bulki- 
35 ness and to present a symmetrical appearance relative to 
the orientation of the light box 21 and microscope 25, 
atc. Associated with the right side panel 37 at  its lower 
rear is a forward wind reel 29 for microfilm 13 and 
4o at its upper rear is a reversed wind reel 30. The forward 
and reversed wind reels 29 and 30 are each secured to  
separate motor shafts extending through the side panel. 
The motors 17 and 18, shown in FIG. 3, are electrically 
connected whereby tension is maintained on the film 
13 as it is being unwound from the reversed wind reel 
45 39 by having the forward wind motor 18 operated to 
ull the film 13 in one direction and the reversed motor 
9 operated in the reversed direction but a t  a very reduced 
oltage or torque. This serves to prevent a snare of 
5o film, keeps the filim firm in its reels, and also prevents 
scratching of the film surface. 
Along right side panel 37 is a lower front shaft with 
an idler or guide reel 43 and an upper front shaft with 
a similar idler reel 45, both for guiding the microfilm 13 
The light box 21 is supported by a projecting member 
47 secured to the right side panel 37. The orientation of 
the light box 21 and member 47 is such as to enable the 
operator of the apparatus 11 to easily view and manipu- 
6o late the inspection devices while facing the front panel 
31. As noted the support member 47 slopes downwardly 
at a slight angle and has an upstanding middle portion 
51 to which is hinged the bottom of the light box 21, as 
illustrated best in FIG. 1. Front and rear lugs 53 and 5 
65 project from the bottom of the light box 21 and extend 
down on opposite sides of the upstanding middle por- 
tion 51. A pin 57 extends through the lugs 53 and 54 
and upstanding middle portion 51 so the light box 21 
may pivot to  the left or right. A pair of screws 61 and 
63 are threaded through the member 47, one on each 
side of the middle portion 51, to serve as a stop for limit- 
ing the pivoting movement of the light box 21. A spring 
20 
30 
55 over the surface of the light box 21. 
3,563,668 
, 66 encircles each s&e nd the springs extend be- 
tween the light box 21 and member 47 to dampen any 
pivoting motion of the box 21 and to stabilize the box 21 
along a vertical axis. 
The light box 21 is shown in section in FIG. 1 and has 
ight 71 mounted on the internal back side of the box 
at the upper end and a stainless steel reflector 73 
curving downward from the light 71 to the bottom of the 
box 21. The light 71 is placed near the top of the box 21 
so as to provide the greatest illumination for the micro- 
scope 25 and densitometer 27. A faceplate 75 of milky 
plastic material is used since it has a finer grain resolu- 
tion than ground glass and thus makes illumination for 
the microscope 25 practical without lenses. 
A support member 77, 79 is secured to each side of the 
light box 21 and extends outwardly at  an angle cor- 
responding to  the slope of the main side support member 
47. Each side support member 77 or 79 has an upstand- 
ing portion so as to form an L-shaped support. The large 
magnifying glass 23 of about four power is secured to 
and extends between the upstanding portions of the side 
support members 77 and 79 for viewing the film 13 as 
it is transported across the lighted face 75 of the light 
box 21. 
On each side of the support members 77 and 79, ad- 
jacent the bottom of their upstanding portions, is pivotally 
secured an elongated mount members 81,82 which extends 
above the support members 77 and 79. The mount mem- 
bers 81 and 82 are bent inwardly toward each other along 
their upper halves. A microscope mount 83 extends be- 
tween and is secured to the two elongated members 81 
and 82 adjacent their upper ends. The microscope mount 
83 has a knob 85 which is geared to move the microscope 
barrel 25 to achieve the best focus of the microfilm image. 
A tubular member 27 extends from the upper portion 
of the microscope mount in which is mounted a photocell 
87 to serve as the densitometer element. The wiring 88 
from the photocell is carried down the inner surface of 
the mount member 83 to the support member 77 and 
into the light box 21. The wiring 88 extends from the 
light box 21 into the housing 15 where is mounted the 
necessary electrical components 91 to obtain light density 
readings on a meter 93 mounted on the front panel 31. 
In taking film density readings with the photocell 27 the 
mount supports 81 and 82 are pivoted so as to place the 
tubular member 27 in contact with the film 13 and to 
press the film 13 against the milky panel 75 of the light 
box 21. By this action the effects of the surrounding or 
ambient light upon the photocell 87 will be minimized 
and an accurate reading obtained. Also, the film being 
held firmly by the photocell housing or tubular member 
27 will permit a more convenient inspection by the micro- 
scope, and time lost in repeated focusing of the micro- 
scope is minimized. A flexible rubber O-ring 93 may be 
fitted to the extremity of the member 2'7 to seal the con- 
tact surface and to preqent scratching of the film emul- 
sion. Also, a suitable photocell selection would be that 
of the cadmiyrn sulfide type since it has a spectral range 
approximately that of the human eye. 
A suitable electrical circuit (not shown) can be pro- 
vided within the main housing 15 whereby the forward 
and reversed reel motors may be regulated by a simple 
control stick 95 mounted within the front panel 31. The 
motors 17 and 18 could thus be speeded up or slowed 
down or even reversed by the action of the operator while 
viewing the microfilm 13 from the functional related de- 
vices described. 
Also, the photocell circuitry could be such that three 
lights 97, 98, 99 mounted in the front panel 31 could 
give a light signal respecting the light density of the film 
13. For example, the left light 97 could go on when the 
film is too dark, the center light 98 could go on when the 
film is all right, and the right light 99 could go on when 
the film is too light. 
As previously noted, the light box 21 may be pivoted 
slightly relative to the housing 15 and principal support 
47. Since the microscope mount 83 is also secured to the 
light housing 21 by the mount members 81 and 82, the 
operator may cause the microscope 25 to pivot to  the 
left and right relative to the microfilm 13 and thus be 
able to observe any portions of the image on the film. 
Obviously, many modifications and variations of the 
present invention are possible in light of the above teach- 
ings. It is, therefore, to be understood that within the 
scope of the appended claims the invention may be 
practiced other than as specifically claimed. 
ing : 
What is claimed is: , 
I. An apparatus for inspection of microfilm compris- 
a main housing: 
a light box secured to said housing; 
said light box having a light diffusing front panel; 
means for transporting microfilm across said light dif- 
a mount having a photocell; 
means pivotally secured to said mount adjacent said 
light box so that an operator may press said photocell 
in contact with the microfilm and thereby obtain an 
accurate light density reading of the microfilm; 
15 
fusing front panel; 
20 
a microscope secured to said mount; 
means for securing said magnifying glass so as to view 
the microfilm transported across said light diffusing 
panel. 
25 a magnifying glass; 
2. An apparatus as defined by claim 1 including: 
a meter secured to the front panel of said main hous- 
ing for indicating the light reading of said photocell. 
3. An apparatus as defined by claim 1 wherein said 
means for transporting microfilm comprises a forward 
motor driven wheel and a reversed motor driven reel. 
4. An apparatus for inspection of microfilm compris- 
ing: 
30 
35 
40 
45 
50 
55 
60 
65 
70 
75 
- 
a housing; 
a support secured to a side of said housing; 
a light box pivotally connected to said support for side- 
spring means tending to stabilize said light box along 
said light box having an illuminated front panel; 
transporting means for moving a strip of microfilm 
over and contiguous to the front of said illuminated 
panel; 
a pair of rigid supports secured to opposite sides and ad- 
jacent the bottom of said light box and extending 
forwardly therefrom; 
a magnifying glass extending between and secured to 
the outer ends of said rigid supports for easy viewing 
of the microfilm strip as it is transported across the 
illuminated front panel; 
a pair of elongated supports each pivotally secured ad- 
jacent their lswer end to one of said rigid supports 
at a location forward of the illuminated front panel; 
a mount secured to and extending between said elon- 
gated supports adjacent their upper end; 
a microscope adjustably secured to said mount for 
enabling an operator to inspect the line quality of the 
images upon the microfilm transported across the 
illuminated front panel; 
a small housing projecting from said mount toward the 
illuminated front panel, said small housing including 
a photocell so that the pivoting of said elongated 
supports may place the small housing in contact 
with said microfilm whereby the photocell will ob- 
tain an accurate indication of the light density of 
the microfilm. 
to-side movement; 
a vertical axis; 
5. An apparatus as defined by claim 4 wherein: 
said light box ha6 an internal light bulb and an internal 
reflector for illuminating the front panel of said 
light box, said front panel being made of a light 
diffusion material. 
6. An apparatus as defined by claim 5 wherein: 
3,563,668 
the light bulb in said light box is placed near the top 
of the light box so as to provide the greatest illumi- 
nation for the microscope and photocell. 
4. An apparatus as defined by claim 4 wherein said 
a motor driven forward reel and a motor driven re- 
versed reel. 2,413,218 12/1946 Coroniti _ _ _ _ _ _ _ _ _ _  250-219X 
8. An apparatus as defined by claim 7 wherein said 3,099,750 7/1963 Swarthout et aI. _ _ _ _ _ _  250-239 
transporting means further includes: 3,393,602 7/1968 Stouffer _ _ _ _ _ _ _ _ _ _  356-186X 
an upper idler reel adjacent and above the illuminated 10 3,473,878 10/1968 Schweitzer _ _ _ _ _ _ _ _  250-217X 
panel of said light box; 
a low idler reel adjacent and below the illuminated 
panel of said light box, so that a roll of microfilm 
may be placed on the reversed reel and guided over 
the upper idler reel and across the face of the illumi- 15 250-219,234 
nated front panel and guidgd over the lower idler 
reel to the forward where it will be stored after in- 
spection. 
References Cited 
5 UNITED STATES PATENTS 
transporting means includes: 
WALTER STOLWEIN, Primary Examiner 
U.S. C1. X.R. 


Apparatus for inspecting microfilm Patent

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