U.S. patent number RE38,986 [Application Number 10/266,422] was granted by the patent office on 2006-02-21 for portable scanning spectrophotometer.
This patent grant is currently assigned to X-Rite, Incorporated. Invention is credited to Douglas V. Baker.
United States Patent |
RE38,986 |
Baker |
February 21, 2006 |
Portable scanning spectrophotometer
Abstract
The specification discloses a portable spectrophotometer (10)
providing improved movement and control of the sample (S) during
analysis. The unit (10) includes a base (12) and an upper assembly
(14) supported on the base (12) for floating movement. Both a
spectral measurement engine (20) and drive rollers (104) are
contained within the upper assembly. The base (12) includes
independently suspended idler rollers (16), and the drive rollers
(104) engage the idler wheels (16), so that at least a portion of
the weight of the upper assembly (14) is borne by the engaging
drive rollers (104) and idler rollers (16). The upper assembly (14)
therefore floats up and down with samples (S) of varying thickness
moving between the rollers (104 and 16). Additional upstream idler
rollers (18 and 24) on the base and the upper assembly engage one
another and bear a portion of the weight of the upper assembly (14)
to create tension in opposition to the drive rollers (104) to hold
the sample (S) taut. A planar media guide (130) is located on the
underside of the upper assembly (14) and surrounds the spectral
engine (20) to engage the sample (S) and reduce flexing and bowing
of the sample (S). A manually actuated backer (30) is supported by
the base (12) to selectively present to the spectral engine (20)
one of two areas (32a and 52b) with different reflective
properties. The unit (10) may include a fast light source (21) in
the spectral engine and a second light source (60) in the backer
(30) so that the spectrophotometer (10) is capable of both
reflective and transmissive analysis.
Inventors: |
Baker; Douglas V. (Middleville,
MI) |
Assignee: |
X-Rite, Incorporated
(Grandville, MI)
|
Family
ID: |
23336456 |
Appl.
No.: |
10/266,422 |
Filed: |
September 1, 1998 |
PCT
Filed: |
September 01, 1998 |
PCT No.: |
PCT/US98/18108 |
371(c)(1),(2),(4) Date: |
July 02, 1999 |
PCT
Pub. No.: |
WO00/12982 |
PCT
Pub. Date: |
March 09, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
09341156 |
Jul 2, 1999 |
06198536 |
Mar 6, 2001 |
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Current U.S.
Class: |
356/402; 250/226;
356/73 |
Current CPC
Class: |
G01J
3/50 (20130101); G01J 3/0272 (20130101) |
Current International
Class: |
G01J
3/51 (20060101) |
Field of
Search: |
;356/73,319,326,328,402,405,406,416,418,419 ;250/226 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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19633557 |
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Mar 1998 |
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DE |
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19716066 |
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Sep 1998 |
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DE |
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0807810 |
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Nov 1997 |
|
EP |
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Other References
"All-In-One Desktop Spectrophotometer," (X-Rite,
Incorporated--Copyright 1999). cited by other .
"Sprectrolino Spectrophotometer," (Gretag Macbeth--Mar. 1998).
cited by other .
Gretag Spectrolino SpectroScan Operating Manual, (Gretag--Undated).
cited by other.
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Primary Examiner: Evans; F. L.
Attorney, Agent or Firm: Warner Norcross & Judd
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A color measurement instrument comprising: an upper assembly
including an underside, a color measurement engine for analyzing a
sample located under said underside, and a plurality of driven
rollers projecting at least partially from said underside for
engaging and moving the sample; and a base including a plurality of
idler rollers and suspension means for independently resiliently
suspending at least selected ones of mid idler rollers for downward
movement under a load, said idler rollers being aligned with and
engaging said driven rollers to at least partially support said
upper assembly on said base, whereby said idler rollers can
individually deflect to accommodate samples of varying thickness
moving between said driven and idler rollers and to otherwise
enhance engagement of said driven and idler rollers.
2. A color measurement instrument as defined in claim 1 wherein
said suspension means is an arm supporting each suspended roller,
all of said arms being integrally molded with and extending from
said base.
3. A color measurement instrument as defined in claim 1 wherein
said driven rollers are positioned to pull the simple past said
color measurement engine and further comprising tension means for
maintaining a tension on the sample, said driven rollers and said
tension means located on opposite sides of said color measurement
engine.
4. A color measurement instrument as defined in claim 1 wherein
said driven rollers are mounted on and driven by a common
shaft.
5. A color measurement instrument as defined in claim 1 wherein
said color measurement instrument comprises a
spectrophotometer.
6. A color measurement system comprising: an upper assembly having
an optical pick-up and a plurality of driven rollers mounted on a
common shaft; a base having a plurality of idler rollers each
aligned with and supporting one of the driven rollers to at least
partially support said upper assembly on said base, said upper
assembly and therefore said shaft being capable of angularly
floating with respect to said base, each of said idler rollers
being independently supported by a resiliently deflectable
suspension arm, whereby all of said driven rollers maintain
engagement with their respective idler rollers to said upper unit
floats to accommodate samples of varying thickness.
7. A color measurement system as defined in claim 6 wherein each of
said suspension arms is integrally molded with said base.
8. A color measurement system as defined in claim 6 further
comprising upper and lower tension rollers on said upper assembly
and said base respectively, said upper and lower tension rollers
engaging one another to apply a tension to a sample being driven by
said drive rollers, said drive rollers and said tension rollers
being opposed to one another across said optical pick-up.
9. A color measurement instrument comprising: an optical pick-up;
drive means for pulling a sample past said optical pick-up in a
first direction; and tension means for impeding the free movement
of the sample in the first direction and thereby creating tension
on the sample as the simple is pulled by said drive means.
10. A color measurement instrument is defined in claim 9 wherein
said tension means is located upstream of said optical pick-up.
11. A color measurement instrument as defined in claim 9 wherein
said tension means comprising a plurality of pairs of pinch rollers
between which the sample passes.
12. A color measurement instrument as defined in claim 11 wherein
at least one of said rollers in each pair is independently
resiliently supported to enable the distance between the rollers to
vary to accommodate samples of varying thickness.
13. A color measurement instrument as defined in claim 9 wherein
said color measurement instrument comprises a
spectrophotometer.
14. A color measurement instrument comprising: a color measurement
engine; drive rollers for engaging and pulling a generally
two-dimensional simple put said color measurement engine; and
tension rollers engaging the sample and acting opposite said drive
rollers for generating tension in the sample as said drive rollers
pull the sample, said drive rollers and said tension rollers
located on opposite sides of said color measurement engine, whereby
the sample is maintained in a generally consistent plane.
15. A color measurement instrument as defined in claim 14 further
comprising an independent suspension for selected ones of said
tension rollers permitting the distance between the tension rollers
to vary.
16. A color measurement instrument comprising: a base including
only idler rollers; an upper assembly supported on said base, said
upper assembly including a plurality of drive rollers aligned with
and engaging at least selected ones of said base idler rollers,
said drive rollers and said idler rollers cooperating to move a
sample between mid base and said upper assembly, said upper
assembly further including a color measurement engine in fixed
physical registration with said drive rollers, whereby said upper
assembly floats with varying thickness samples between said drive
rollers and said idler rollers to maintain a desired spacing
between the sample and said color measurement engine.
17. A color measurement instrument as defined in claim 16 further
comprising suspension means for independently suspending at least
selected ones of said base idler rollers under said drive
rollers.
18. A color measurement instrument as defined in claim 16 further
comprising means for resisting movement of the sample, said drive
rollers and said tension means being opposite one another across
said id color measurement engine, said tension moms enhancing
positioning of the sample in a consistent plane.
19. A color measurement instrument as defined in claim 18 wherein:
said drive rollers and said driven rollers defies a plane; and said
upper assembly further includes a planar media guide aligned with
mid color measurement engine and coplanar with the plane, said
media guide thereby engaging the sample to reduce flexing and
bowing of the sample to further enhance uniform spacing between the
sample and said color measurement engine.
20. A color measurement instrument as defined in claim 16 wherein
said color measurement instrument comprises a
spectrophotometer.
21. A color measurement instrument comprising: a base including
only idler rollers defining a fast plane; an upper assembly
including upper rollers defining a second plane, said upper rollers
aligned with said base rollers to at least partially support said
upper assembly on said base; drive moans within mid upper assembly
for driving at least selected ones of said upper rollers to move a
sample located between said upper rollers and said idler rollers; a
color measurement engine within said upper assembly for color
analyzing the sample located between the rollers, said engine
having a desired physical registration with the second plane; and
said upper assembly including a generally planar portion generally
coplanar with the second plane, said planar portion engaging the
sample to register the color measurement engine with respect to the
sample.
22. A color measurement instrument as defined in claim 21 wherein
selected others of said upper rollers are tension rollers, said
tension rollers engaging the sample to resist movement of the
sample to tension the sample and enhance its consistent positioning
with respect to the color measurement engine.
23. A color measurement instrument as defined in claim 21 further
comprising as independent resiliently deflectable suspension for
selected ones of said base idler rollers.
24. A color measurement instrument as defined in claim 21 wherein
said planar portion comprises a sheet of relatively low-friction
material proximate said color measurement engine.
25. A color measurement instrument comprising: a base; an upper
assembly including an underside facing said base, a color
measurement engine for analyzing a sample located between said
underside and said base, and a plurality of rollers for engaging
the sample to move the sample with respect to the color measurement
engine, said rollers projecting a first distance from said
underside, said upper assembly further including a media guide on
said underside and aligned with said color measurement engine, said
media guide being planar and having a thickness approximately equal
to the first distance that said rollers project from said
underside, whereby said media guide also engages the sample to
assist in reducing flexing and bowing of the sample.
26. A color measurement instrument as defined in claim 25 wherein
said media guide comprises a relatively low-friction material.
27. A color measurement instrument as defined in claim 25 wherein
said media guide defines an aperture aligned with said color
measurement engine.
28. A color measurement instrument as defined in claim 25 wherein
said color measurement instrument comprises a
spectrophotometer.
29. A color measurement instrument comprising: a base; an upper
assembly including an underside facing said base; a color
measurement engine within said upper assembly; drive means within
said upper assembly for engaging and moving a sample between said
base and mid upper assembly for analysis by said color measurement
engine; tension means for creating tension in the sample as the
sample is moved by mid drive means; and a generally planar media
guide on said underside of said upper assembly, said media guide
defining an aperture aligned with the color measurement engine,
said media guide engaging the sample and applying at least a
portion of the weight of the upper assembly to the engaged portion
of the sample to reduce flexing and bowing of the sample.
30. A color measurement instrument as defined in claim 29 wherein
mid media guide comprises a relatively low-friction material.
31. A spectrophotometer capable of .[.operation in either a.].
reflective .[.analysis mode or a.]. .Iadd.and .Iaddend.transmissive
.[.analysis mode.]. .Iadd.measurements.Iaddend., said
spectrophotometer comprising: a scanning station; drive means for
moving a sample through mid scanning station .Iadd.in at least a
linear direction, said drive means engaging the sample downstream
of said scanning station.Iaddend.; .[.a.]. spectral measurement
engine .[.including an optical pick-up.]. .Iadd.means .Iaddend.for
collecting spectral information from .[.a.]. .Iadd.the
.Iaddend.sample, said .Iadd.spectral measurement engine means
including at least one .Iaddend.optical pick-up .[.being.]. located
on a first side of said scanning station; a first illuminator
located on the first side of the scanning station for activation
.[.only when said spectrophotometer is operated in the.]. .Iadd.in
conjunction with .Iaddend.reflective .[.analysis mode.].
.Iadd.measurements.Iaddend.; and a second illuminator located on a
second side of the scarring station for activation .[.only when
said spectrophotometer is operated in said.]. .Iadd.in conjunction
with .Iaddend.transmissive .[.analysis mode.].
.Iadd.measurements.Iaddend., the second side being opposite the
first side across said scanning station.
32. A spectrophotometer .[.as defined in claim 31 wherein.].
.Iadd.capable of operation in either a reflective analysis mode or
a transmissive analysis mode, said spectrophotometer
comprising.Iaddend.: .[.said.]. .Iadd.a .Iaddend.scanning station
.[.is.]. positioned above a base; .Iadd.drive means for moving a
sample through said station; a spectral measurement engine
including an optical pick-up for collecting spectral information
from a sample, said optical pick-up being located on a first side
of said scanning station; a first illuminator located on the first
side of the scanning station for activation only when said
spectrophotometer is operated in the reflective analysis
mode.Iaddend.; and .Iadd.a second illuminator located on a second
side of the scanning station for activation only when said
spectrophotometer is operated in said transmissive analysis mode,
the second side being opposite the first side across said scanning
station, .Iaddend.said second illuminator .[.is.]. supported by a
backer that is capable of ready manual removal from said base, for
example, when transmissive operation is not desired.
33. A spectrophotometer .[.as defined in claim 31 wherein.].
.Iadd.capable of operation in either a reflective analysis mode or
a transmissive analysis mode, said spectrophotometer
comprising.Iaddend.: .[.said.]. .Iadd.a .Iaddend.scanning station
.[.is.]. positioned above a base; .Iadd.drive means for moving a
sample through said scanning station; a spectral measurement engine
including an optical pick-up for collecting spectral information
from a sample, said optical pick-up being located on a first side
of said scanning station; a first illuminator located on the first
side of the scanning station for activation only when said
spectrophotometer is operated in the reflective analysis
mode.Iaddend.; and .Iadd.a second illuminator located on a second
side of the scanning station for activation only when said
spectrophotometer is operated in said transmissive analysis mode,
the second side being opposite the first side across said scanning
station, .Iaddend.said second illuminator .[.is.]. supported by a
backer manually operable between a transmissive position wherein
said second illuminator is aligned with said optical pick-up and a
reflective position where.Iadd.in .Iaddend.said second illuminator
is unaligned with said optical pick-up.
34. A spectrophotometer capable of performing both reflective and
transmissive spectral analysis, said spectrophotometer comprising:
a base; .[.an upper assembly supported by said base;.]. .[.a.].
.Iadd.at least one .Iaddend.spectral measurement engine supported
.[.by.]. .Iadd.above .Iaddend.said .[.upper assembly.].
.Iadd.base.Iaddend.; drive means for moving a sample between said
.Iadd.at least one .Iaddend.spectral measurement engine and said
base.Iadd., said drive means engaging the sample downstream of said
at least one special measurement engine.Iaddend.; a first
illumination source .[.supported by said upper assembly.]. to be
activated when said spectrophotometer performs reflective analysis;
and a second illumination source .[.supported by said base.]. to be
activated when said spectrophotometer performs transmissive
analysis.
35. A spectrophotometer .[.as defined in claim 34.]. .Iadd.capable
of performing both reflective and transmissive spectral analysis,
said spectrophotometer comprising: a base; an upper assembly
supported by said base; a spectral measurement engine supported by
said upper assembly; drive means for moving a sample between said
spectral measurement engine and said base; a first illumination
source supported by said upper assembly to be activated when said
spectrophotometer performs reflective analysis; a second
illumination source supported by said base to be activated when
said spectrophotometer performs transmissive analysis; and.Iaddend.
wherein said base includes a backer manually operative between a
transmissive position wherein said second illumination source is
aligned with said spectral measurement engine and a reflective
position wherein said second illumination source is unaligned with
said spectral measurement engine.
36. A spectrophotometer as defined in claim 35 wherein said backer
is readily manually removable from said base, whereby said backer
may be easily removed and replaced with an alternative backer
suitable only for reflective analysis.
.Iadd.37. A spectrophotometer as defined in claim 31 wherein said
drive means engages the sample only downstream from said scanning
station..Iaddend.
.Iadd.38. A spectrophotometer as defined in claim 31 further
comprising a sample path means for defining a sample path that is
planar from a sample entrance position to a sample exit
position..Iaddend.
.Iadd.39. A spectrophotometer as defined in claim 34 wherein said
drive means engages said sample only downstream from said scanning
station..Iaddend.
.Iadd.40. A spectrophotometer as defined in claim 34 further
wherein said spectrophotometer defines a planar sample path through
said spectrophotometer..Iaddend.
.Iadd.41. A spectrophotometer comprising: a scanning station; drive
means for moving a sample through said scanning station; spectral
measurement engine means for collecting spectral information from
the sample, said spectral measurement engine means located on a
first side of said scanning station; engine support means for
supporting said spectral measurement engine means at a controlled
distance from the sample, said engine support means adapted to
engage the sample to maintain a desired physical relationship
between the sample and the spectral measurement engine means; and a
first illuminator located on the first side of the scanning station
for illuminating the sample for reflective
measurement..Iaddend.
.Iadd.42. A spectrophotometer as defined in claims 41 wherein said
engine support means engages the sample as the sample moves through
said spectrophotometer..Iaddend.
.Iadd.43. A spectrophotometer as defined in claim 42 wherein said
engine support includes said drive means..Iaddend.
.Iadd.44. A spectrophotometer as defined in claim 41 wherein said
spectral measurement engine and said engine support means are
oriented so that gravity draws them toward the sample..Iaddend.
.Iadd.45. A spectrophotometer as defined in claim 41 further
comprising a second illuminator located on a second side of the
scanning station for illuminating the sample for transmissive
measurement, the second side being opposite the first side across
said scanning station..Iaddend.
.Iadd.46. A spectrophotometer comprising: a base; at least one
spectral measurement engine; drive means for moving a sample
between said at least one spectral measurement engine and said
base; engine support means for supporting said at least one
spectral measurement engine means above said base a controlled
distance in registration with the sample, said engine support means
adapted to engage the sample to maintain a desired physical
relationship between the sample and the spectral measurement engine
means; and a first illumination source to be activated for
reflective measurement of the sample..Iaddend.
.Iadd.47. A spectrophotometer as defined in claim 46 wherein said
engine support means includes said drive means..Iaddend.
.Iadd.48. A spectrophotometer as defined in claim 46 wherein said
engine support means includes rollers engaging the
sample..Iaddend.
.Iadd.49. A spectrophotometer as defined in claim 46 wherein said
at least one spectral measurement engine and said engine support
means are oriented so that their mass is directed toward the sample
under the force of gravity..Iaddend.
.Iadd.50. A spectrophotometer as defined in claim 46 further
comprising a second illumination source to be activated for
transmissive measurement of the sample..Iaddend.
Description
TECHNICAL FIELD
The present invention relates to color measurement instruments, and
more particularly, to spectrophotometers.
BACKGROUND ART
Color measurement instruments for many and varied applications are
well known. Them instruments are used, for example, to determine
color consistency in primed material, photographic material,
textiles, and plastics. The most comprehensive color measurements
are obtained by instruments known as spectrophotometers, which
measure the spectral distribution of light and give a percentage
reflection or transmission at many segments in the visible color
spectrum.
The field of desk top publishing has expanded greatly in recent
years, and color output devices such as color printers, plotters,
proofers have become widely used. The color output devices are
often controlled by computer software, which transmits control
signals to the printer defining color to be produced. To assure
color quality, it is desirable to be able to calibrate color
printers to produce a selected quality of color for printed
material produced by a number of different printers. Additionally,
data defining a color product may be transmitted to remote
locations to be printed by a variety of printers. In order to be
able to provide a product of consistent color characteristics, a
comparison to a color standard is requited. All of them functions
requite the accurate measurement of many samples of different
colors, produced on the device. These colors are produced using
only a few colorants-usually cyan (C), magenta (M), yellow (Y), and
black (K).
A color measurement instrument, such as a spectrophotometer,
includes a color measurement engine having an optical pick-up.
Additionally, many instruments include a drive mechanism for moving
either the sample or the engine to effect relative movement between
the two. The registration of the sample with respect to the engine
and the controlled movement of the sample or the engine are
critical components in obtaining consistent and accurate
measurements. Only mail changes in the distance between the sample
and the measurement engine can create significant errors and
inconsistencies in the color measurement.
Prior color measurement instruments are illustrated in U.S. Pat.
No. 5,369,494 issued Nov. 29, 1994 and entitled "Portable Scanning
Colorimeter"; U.S. Pat. No. 5,118,183 issued Jun. 2, 1992 and
entitled "Automated Strip Reader Densitometer" and U.S. Pat. No.
5,062,714 issued Nov. 5, 1991 and entitled "Apparatus and Method
for Patter Recognition." In these units, the sample drive mechanism
is located in the base, while the color measurement engine is
located in an assembly above the base. Because these two primary
components are located in different housings, there is the
possibility that sample registration and movement is not as
precisely controlled as required for present day measurement.
Accordingly, artisans continue to seek improved structures for
maintaining improved consistency and accuracy in sample
registration and movement.
DISCLOSURE OF INVENTION
The aforementioned issues are addressed in the present invention
providing improved sample registration and movement within a
portable spectrophotometer. The instrument contains a mechanical
drive system that transports the sample past the measurement engine
to a precise fashion.
First, the spectrophotometer includes a base and an upper assembly
supported for floating movement on the base. Both the color
measurement engine and the sample drive mechanism are located
within the upper assembly. As the sample is drawn between the base
and the upper assembly, the upper assembly can float with samples
of various and varying thickness. This approach reduces or even
eliminates the need for separate tensioning devices within the
drive system, such as springs and/or close tolerances.
Second, the drive mechanism includes a plurality of drive wheels,
and the base includes a plurality of independently suspended idler
rollers, each of which engages and supports one of the drive
wheels. The independently suspended rollers flex to accommodate
samples of varying and various thicknesses.
In a third embodiment of the invention, the drive rollers are
located "downstream" (in the direction of sample travel) from the
color measurement engine. Tension rollers are provided upstream of
the color measurement engine to at least partially resist movement
of the sample in response to the drive rollers. The tension created
within the sample improves its consistent maintenance in a uniform
plane and therefore its consistent registration with the color
measurement engine.
In a fourth embodiment of the invention, a planar, low-friction
media guide is located on the underside of the upper assembly to
engage the top surface of the sample. The thickness of the media is
approximately the same as the distance that the drive wheels extend
from the upper assembly, so that the media guide consistently
engages the top surface of the sample. Therefore, the media guide
improves the registration of the sample with respect to the color
measurement engine; and the media guide assists the upper assembly
in riding the top surface of the sample.
In a fifth embodiment, a two-position backer is provided in the
base. The backer includes two separate areas with different
reflective properties. The backer is readily manually movable so
that either of the two areas can be aligned with the optical pickup
of the color measurement engine. For example, the two areas may be
white light diffusing opal and stable uniform black. In an
alternative embodiment, the light diffusing opal may be illuminated
for transmissive analysis.
In a sixth aspect of the invention, the spectrophotometer is
capable of both reflective and transmissive analysis. A first light
source is included within the color measurement engine and is
activated only when reflective analysis is desired. A second tight
source is included within the base, is aligned with the color
measurement engine, and is activated only when transmissive
analysis is desired.
These and other objects, advantages, and features of the invention
will be more readily understood and appreciated by reference to the
description and the drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a right front perspective view of the spectrophotometer
of the present invention;
FIG. 2 is a left front perspective view of the
spectrophotometer;
FIG. 3 is a perspective view of the spectrophotometer with the base
components exploded;
FIG. 4 is a perspective view of the base;
FIG. 5 is a top plan view of the base showing the backer in a first
position;
FIG. 6 is a top plan view of the base showing the backer in its
second position;
FIG. 7 is a bottom plan view of the base showing the backer in the
second position;
FIG. 8 is a sectional view taken along line VII--VII in FIG. 5;
FIG. 9 is a perspective view of the underside of the base with an
alternative backer capable of illumination;
FIG. 10 is a perspective exploded view of the upper assembly;
FIG. 11 is a front elevation view of the drive shaft and motor;
FIG. 12 is an enlarged perspective view of the drive shaft
bearing;
FIG. 13 is a fragmentary bottom plan view of the upper assembly
showing the media guide; and
FIG. 14 is a sectional view of the spectrophotometer taken along
the line XIV--XIV in FIGS. 1 and 2.
MODE FOR CARRYING OUT THE INVENTION
A spectrophotometer constructed in accordance with a preferred
embodiment of the present invention is illustrated in the drawings
and generally designated 10. As perhaps best illustrated in FIGS. 3
and 10, the spectrophotometer includes a base 12 and an upper
assembly 14 supported on the base. The base includes two sets 16
and 18 of idler rollers. The upper assembly 14 includes a spectral
analysis engine 20, a drive assembly 22, and tension rollers 24.
The engine 20 includes an optical pick-up 75. The drive rollers 22
of the upper assembly engage the idler rollers 16 of the base, and
the tension rollers 24 of the upper assembly engage the idler
rollers 18 of the base all to partially support the upper assembly
14 on the base 12. The drive rollers 22 pull or draw the sample S
(see FIG. 1) through the spectrophotometer 10 and past the optical
pick-up 75. The tension rollers 24 create a tension on the sample S
to maintain the sample in a consistent plane.
I. Base
The base is perhaps beat illustrated in FIGS. 3-8. Generally, the
base 12 includes a body 26, idler rollers 16 and 18, and a backer
30.
The body 26 is plastic and includes a connector portion 32 and a
sample portion 34. The connector portion 32 includes a platform 36,
a pair of alignment pins 35a and 35b, and a pair of integrally
molded spring clips 38. The platform 36 provides so engagement
surface for the upper numbly 14. The pins 35a and 35b interfit with
apertures 97a and 97b (see FIG. 10) respectively to prevent
relative rotation of the upper assembly 14 on the base 12 in a
horizontal plane. The spring clips 38 include catches 39 (see FIG.
4) above the platform 36 and actuating portions 40 (see FIGS. 7 and
9) that extend through and below the platform. The actuating
portions may be manually actuated from the underside of the but 12
to release the upper assembly 14 from the base 12.
The sample portion 34 of the base 12 is generally planar and
supports the idler rollers 16 and 18 and the backer assembly 30.
The forward edge 41 of the platform is rounded to facilitate
insertion of the sample S between the base 12 and the upper
assembly 14. A 35 mm groove or guide 43 in the forward edge 41
facilitates insertion and alignment of a strip of 35 mm film (not
shown). A race-track shaped window 39 is defined is a central
portion of the sample portion 34.
The body base includes integral fingers 47a, 47b, and 47c on its
underside. The finger 47a is opposed to the fingers 47b and 47c,
and the fingers slidingly receive the backer assembly 30 as will be
described. A foot 45 is mounted at each of the four corners of the
base body. Preferably, the feet are fabricated of a relatively
high-friction material to assist in securely support the unit 10 on
a smooth surface.
All of the idler rollers 16 and 18 are generally identical to one
another. In the preferred embodiment, each is fabricated on
plastic. As seen in FIG. 3, each includes a roller body 16a or 18a
and a pair of stub shafts 16b or 18b extending therefrom.
Each of the rollers 16 is supported by a suspension arm 40. Each of
the suspension arms 40 terminates in a bearing portion 42 which
receives the stub shafts 16b and rotatably supports the associated
roller 16. Each of the suspension arms 40 is integral with the
remainder of the base body 26. The base 26 is fabricated of a
resiliently flexible plastic, and therefore each of the arms 40 is
resiliently deflectable downwardly under the weight of the upper
assembly 14.
Similarly, each of the idler rollers 18 is supported for
independent suspension on a suspension arm 46. Each of the
suspension arms terminates in a bearing portion 46 for which
receives the stub shafts 18b and rotatably supports the associated
roller 18. As with arms 40, suspension arms 44 are resiliently
deflectable in the downward direction under the weight of the upper
assembly 14. When not deflected, the rollers 16 and 18 lie within
and define a plane. The rollers 16 and 17 are retained in the
bearing portions 42 and 46 because the stub shafts 16b and 18b
extend under the sample portion 34. Any of the rollers 16 and 17
can be removed by pressing the supporting arm downwardly and
lifting the roller from the bearing portion.
The backer assembly 30 is illustrated in FIGS. 3 and 7-8 and
includes a body 49, a spring plunger 50, and an opal glass 51. The
body 49 is held between fingers 47a on one side and 47b and 47c on
the other side for sliding movement. The spring plunger 50
cooperates with deters (not visible) in the underside of the base
body 26 to releasably catch the assembly in either of two opposite
positions. The backer body 49 includes a recessed area 34 that
facilitates removal of the backer assembly 30 from the base body 26
when the recessed area 54 is aligned with the finger 47a.
The body 49 includes a platform portion 52 extending upwardly from
the remainder of the body 49 and into the window 39 of the base
body 26. The platform provides two separate areas with different
reflective properties. The first area 57a is stable uniform black.
The second area 52b supports the white fight diffusing opal glass
51. The white opal glass 51 is secured in position on the platform
52 using a solvent adhesive or other suitable interconnection
means.
An alternative backer assembly 30' is illustrated in FIG. 9. The
alternative backer assembly 30' is capable of providing
illumination for operation of the spectrophotometer 10 in a
transmissive mode of analysis. In the alternative backer 30', an
illumination source 60 is positioned within the cavity 37 directly
below the opal glass 51 (see FIG. 8). A power cord 62 extends from
the backer assembly 30' and terminates in a plug 64 mounted within
the backer base 26. The cord 62 is secured under wire management
fingers 66, which are integral with the base body 26. The plug or
connector 64 is held in position by the base body 26 for automatic
correction with the upper assembly 14 when the upper assembly 14 is
installed on the base 12.
II. Upper Assembly
The upper assembly 14 is illustrated in FIGS. 10-14. The upper
assembly 10 includes a housing 70, a spectral measurement engine
20, a drive assembly 22, and a lower plate 72.
The housing 70 is injection molded of plastic to house the
remaining upper assembly components. The housing includes an
integral alignment mark 71 centered above the film strip guide 43
and linearly aligned with the spectral engine 20 to artist a user
with properly aligning the sample S for scanning by the engine.
The spectral measurement engine 20 of the preferred embodiment is
generally well known to those skilled in the all. For example, one
suitable spectral engine is illustrated co-pending application Ser.
No. 08/714,969 filed Sep. 17, 1996 by Berg et al and entitled
"Compact Spectrophotometer," the disclosure of which is
incorporated by reference. Other measurement engines, such as those
for calorimeters and densitometers, can be used depending on the
application. Generally speaking, the engine 20 includes an optics
assembly 74, a printed circuit board (PCB) assembly 76, and a
control board shield 78. The optics assembly 74 includes an optical
pick-up 75 (see FIG. 14). The PCB assembly 76 and the shield 78 are
secured to the optics assembly 74 using screws 80 and star lock
washers 82. The optics assembly 74 is secured to the aluminum
stand-offs on the bottom plate 72 using screws 81 and star lock
washers 83. Additionally, the bottom plate 72 is secured to the
optics assembly 74 using screws 85. The aluminum bottom plate 72
and the aluminum standoffs 98 dissipate heat generated by the
optics assembly and most notably by the illuminators 77. A wire tie
87 is included for wire management
A plurality of illuminators 77 (see FIG. 14) are included within
the spectral engine 20 to illuminate the sample S when the unit 10
is operated in the reflective analysis mode. The illuminators 77 an
actuated only in the reflective mode (i.e. not in the transmissive
mode).
The bottom plate 72 is generally planar, is fabricated of aluminum
and provides an underside to the upper assembly 14. The perimeter
of the bottom plate 72 is dimensioned to closely fit within the
bottom of the housing 70. The plate 72 is secured to the housing 70
using screws 73.
The plate define two rectangular apertures 96 that receive the
locking arms 38 of the base 12. When the upper assembly 14 is
attached to the base 12, the catches 39 of the locking arms 38
engage the upper surface of the bottom plate to lock the upper
assembly on the base; and the bottom plate 72 rests upon the
platform 36 of the base 12 to at least partially support the weight
of the upper assembly. The plate further defines two alignment
apertures 97a and 976 that receive the alignment pins 35a and 35b
respectively of the base 12. The interest of the locking arms 38
within the apertures 96 and the interest of the alignment pins 33
within the apertures 97 prevents the upper assembly from rotating
in a generally horizontal plane, but permits the upper assembly to
float or pivot in a generally vertical plane.
The plate 72 defines a series of elongated apertures 90 through
which drive milers extend, a pair of elongated apertures 92 through
which idler rollers extend, and an optics aperture 94 aligned with
the optical pick-up 73 (see FIG. 14).
The drive assembly 22 (see FIGS. 10-11) includes a drive shell
assembly 100 and a motor assembly 102. The drive shaft is secured
to the motor assembly using set screws 103. The drive shaft
assembly 100 includes five drive wheels 104 of uniform diameter
with the wheels being evenly spaced from one another. Because the
upper assembly is free to float in a vertical plane, the drive
shaft assembly is also free to float in a vertical plane. The
individual suspension of the idler rollers 16 under the drive
rollers 104 accommodates such angular floatation.
Each of the wheels 104 defines a circumferential groove 106 (see
FIG. 11). An O-ring 108, which acts as a tire, is fitted within
each of the grooves 106. Each of the O-rings is fabricated of a
relatively high-friction material for gripping the sample to be
analyzed. The material of the preferred embodiment is precision
silicone. The motor assembly 102 is generally well known in the
art. The motor of the preferred embodiment is a high-torque gear
motor or a stepper motor. The drive rollers 104 extend through
apertures 90 to extend approximately 0.3 millimeter (mm) from the
lower surface of the bottom plate 72 (see FIG. 14). As currently
implemented, the drive assembly moves or pulls the sample S at a
speed of approximately 3 centimeters (cm) per second.
The drive assembly 22 is severed to the bottom plate 72 by the
drive bearings 110 illustrated in greatest detail in FIG. 12. Each
of the drive bearings 110 is generally U-shaped, defining an
interior having a circular portion 112 and a pair of opposed flat
portions 114. The distance between the flat portions 114 is less
than the diameter of the circular portion 112. The drive bearings
110 are fabricated of bearing-quality plastic or other resiliently
deformable material. Accordingly, the legs can be spread slightly
to fit the bearing over the drive shaft 100. The drive shaft then
dicks into the circular portion 112. Screws 116 (FIG. 10) are
inserted through holes 118 in the bearing 110 to lock the drive
shaft within the circular portion 112 and to secure the bearing to
the bottom plate 72. Lubricant preferably is included within the
bearing 110 to facilitate rotation of the drive shaft 100.
Idler rollers 24 (see FIG. 10) are rotatably supported on the
bottom plate 72 by way of bearings 120 and screws 122. The idler
rollers 24 extend through apertures 92 to extend approximately 0.3
millimeter (mm) from the lower surface of the bottom plate 72 (see
FIG. 14).
The media guide 130 is illustrated in FIGS. 3 and 13-14 and is a
generally planar piece of relatively low-friction material. The
preferred material of the present embodiment is a bearing-quality
material that is soft enough to avoid damage of the sample S. As
currently implemented, the material is a high-density
polypropylene. As viewed in FIG. 3, the media guide is milkman
shaped having a relatively narrow forward portion 132 to fit
between the idler rollers 24. The rearward portion 134 defines a
central aperture 136 aligned with the optics aperture 94 in the
base plate 72 and with the optical pickup 75 of the color
measurement engine 20. The media guide 130 is adhered to the bottom
plate 72 using a pressure-sensitive adhesive or other suitable
attachment means. The thickness of the media guide is approximately
0.3 mm so that it projects from the lower plate 72 approximately
the same distance that the idler rollers 24 and the drive rollers
104 project from the lower plate 72. Consequently, the rollers 24
and 104 mad the media guide 130 all lie within and define a
plane.
As seen in FIG. 1, the upper assembly further includes a 12-volt
power connection 132 for powering the unit 10, an RS-232 port 134
for serial communication with a personal computer (PC) or other
digital device, and a push-button 136 for actuating and operating
the unit
III. Operation
The operation of the spectrophotometer 10 is perhaps best
illustrated in FIGS. 1 and 14. For purposes of reference, the area
above the backer assembly 30 and below the optical pick-up 75 is
referred to as the scanning station 140. The backer assembly 30 is
aligned with the optical pick-up across the scanning station.
If necessary, the reflectance of the backer assembly 30 is selected
by manually sliding the backer assembly to either of its two
selectable positions. In the fast position, the stable uniform
black portion 52a of the platform 52 is presented to the cola
measurement engine 20. In the second position, the white light
diffusing opal glassy 51 in portion 52b is presented to the engine
20.
A sample S (FIG. 1), having color patches S', to be analyzed is
aligned with the alignment mart 71 on the upper assembly and fed or
pushed between the base 12 and the upper assembly 14. The leading
edge of the sample S passes between the tension rollers 24 on the
upper assembly and the idler rollers 18 on the base. The sample
continues through the scanning station 140 until the forward edge
of the sample S is gripped by the drive wheels 104, whereupon the
sample is pulled between the drive rollers and the associated idle,
rollers 16. Spectral analysis or other color measurement operations
are conducted on the sample S as it is drawn past the color
measurement engine 20 and specifically the optical pickup 73.
As the sample moves between the idler rollers 18 and 24, the
suspension arms 44 flex to permit the individual rollers 18 to move
downwardly. Similarly, as the sample is drawn between the drive
rollers 104 and the idler rollers 16, the individual suspension
arms 40 flex to permit the rollers 16 to move downwardly. Also, the
tension rollers 24 and the drive rollers 108 engage and ride along
the top surface of the sample S to assist in registration of the
sample with respect to the optical pick-up 73. The free floating
ability of the upper assembly 14 and the individual suspension of
the idler rollers 18 facilitate the accurate color measurement of
samples of varying thickness. The upper assembly 14 rides along the
top surface of the sample S to maintain a desired physical
registration or relationship between the top surface of the simple
and the engine 20.
As noted above, the tension rollers 24, the drive rollers 104, and
the media guide 130 all project a substantially equal distance from
the bottom plate 72. Accordingly, the media guide 130 also engages
the top surface of the sample S to further assist in registration.
The media guide 130 prevents flexing or bowing of the sample within
the scanning station as may occur, for example, if the trailing
edge of the sample is dropped below or is lifted above the level of
the scanning station 140.
The spectrophotometer may be operated in either the reflective or
the transmissive mode. When operated in the reflective mode, only
the illuminators 77 are actuated so that the top surface of the
sample S is illuminated in accordance with the ANSI standard
45.degree./0.degree. reflection measurement. When operated in the
transmissive mode, only the base illuminator 60 within the backer
assembly 30 is actuated to illuminate the sample from beneath in
accordance with the ANSI standard 180.degree./0.degree.
transmissive measurement.
The above descriptions are those of preferred embodiments of the
invention. Various alterations and changes can be made without
departing from the spirit and broader aspects of the invention as
defined in the appended claims, including the Doctrine of
Equivalents.
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