U.S. patent application number 10/859835 was filed with the patent office on 2005-01-20 for system and method for discriminating a roll in a paper roll dispenser, and a paper roll.
This patent application is currently assigned to CASCADES GROUPE TISSU INC.. Invention is credited to Dion, Marcel, Lemaire, Alain, Lemaire, Laurent, Martin, Yves, Ruel, Francois.
Application Number | 20050011987 10/859835 |
Document ID | / |
Family ID | 33557495 |
Filed Date | 2005-01-20 |
United States Patent
Application |
20050011987 |
Kind Code |
A1 |
Lemaire, Alain ; et
al. |
January 20, 2005 |
System and method for discriminating a roll in a paper roll
dispenser, and a paper roll
Abstract
The invention comprises a system and a method for discriminating
a roll placed in a paper roll dispenser, as well as a paper roll
with a core comprising at least one passive element having an
electrical conductivity different from that of the core, to be used
in conjunction with the dispenser. The system comprises at least
two conducting plates located within the paper roll dispenser such
that when the roll is positioned within the dispenser, the plates
are in proximity of the roll, the plates being electrically
insulated from each other, means for detecting capacitance between
the plates and generating a signal indicative of said capacitance
and means for discriminatng said paper roll based on a value of the
signal.
Inventors: |
Lemaire, Alain; (Kingsey
Falls, CA) ; Lemaire, Laurent; (Warwick, CA) ;
Ruel, Francois; (Victoriaville, CA) ; Dion,
Marcel; (Kingsey Falls, CA) ; Martin, Yves;
(Kingsey Falls, CA) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
CASCADES GROUPE TISSU INC.
Candiac
CA
|
Family ID: |
33557495 |
Appl. No.: |
10/859835 |
Filed: |
June 2, 2004 |
Current U.S.
Class: |
242/563 |
Current CPC
Class: |
A47K 10/3662
20130101 |
Class at
Publication: |
242/563 |
International
Class: |
B65H 026/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2003 |
CA |
2,430,150 |
Claims
1. A system for discriminating a roll placed in a paper roll
dispenser, comprising: at least two conducting plates located
within the paper roll dispenser such that when the roll is
positioned within the dispenser, the plates are in proximity of the
roll, the plates being electrically insulated from each other;
means for detecting capacitance between the plates and generating a
signal indicative of said capacitance; and means for discriminating
said paper roll based on a value of the signal.
2. The system of claim 1, wherein the at least two conducting
plates are shaped and positioned in an annular fashion in proximity
of a roll support structure within the dispenser.
3. The system of claim 2, wherein the means for detecting detects
the capacitance between an individual pair of adjacent plates of
said plates in a sequenced manner one pair after another such that
all combinations of capacitance between adjacent conducting plates
are detected.
4. The system of claim 1, wherein the means for detecting
comprises: means for applying voltage between two adjacent plates
of said plates; means for measuring voltage between two adjacent
plates of said plates; control means for controlling said means for
applying and means for measuring to scan each pair of said plates
by sequentially applying the voltage between the plates of the pair
during a given time period, and either measuring the charge or
discharge rate of voltage between the plates of the pair to produce
said signal.
5. The system of claim 4, wherein the means for applying voltage is
an oscillator.
6. The system of claim 4, wherein the means for measuring voltage
is integrated in a microprocessor.
7. The system of claim 6, wherein the control means is integrated
in the microprocessor.
8. The system of claim 1, wherein the means for discriminating said
paper roll comprises comparing means which compares the value of
said signal to a reference signal.
9. The system of claim 8, wherein the comparing means is a
microprocessor.
10. The system of claim 1, further comprising means for
compensating said signal for changes in an environment surrounding
the system.
11. The system of claim 10, wherein the means for compensating is
integrated in a microprocessor.
12. The system of claim 1, comprising means for detecting a
placement of the roll in the system.
13. The system of claim 1, comprising means for informing a user of
results of an assessment made by the means for discriminating.
14. The system of claim 13, wherein the means for informing the
user comprises a green light and a red light, either one being
activated depending on the results of the assessment made by the
means for discriminating.
15. The system of claim 4, further comprising means for converting
said signal into a continuous voltage.
16. A method for discriminating a roll placed in a paper roll
dispenser comprising the steps of: a) placing the roll in the
dispenser; b) providing at least two conducting plates located
within the paper roll dispenser such that when the roll is
positioned within the dispenser, the plates are in proximity of the
roll, the plates being electrically insulated from each other; c)
detecting capacitance between the plates; d) generating a signal
indicative of said capacitance; and e) discriminating said paper
roll based on a value of the signal
17. The method of claim 16 further comprising the steps of:
detecting a placement of the roll in the system after step a) and
before step c); and initiating step c) upon detection of the
placement of the roll in the system.
18. The method of claim 16, wherein: step b) comprises the step of
providing at least two conducting plates shaped and positioned in
an annular fashion in proximity of a roll support structure within
th dispenser; step c) comprises the steps of applying voltage
between two adjacent plates of said plates; and measuring voltage
between two adjacent plates of said plates; step d) comprises the
steps of scanning each pair of said plates by sequentially applying
the voltage between the plates of the pair during a give time
period, and either measuring the charge or discharge rate of
voltage between the plates of the pair to produce said signal; and
compensating said signal for changes in an environment surrounding
the system; and step e) comprises the steps of comparing said
signal to a reference signal to obtain an assessment of the signal;
converting said assessment signal into a continuous voltage; and
informing a user of results based on the continuous voltage.
19. A paper roll comprising a core having at least one passive
element having an electrical conductivity different from that of
the core.
20. The paper roll of claim 19, wherein the core has a hollow
cylindrical shape and comprises at least two strips of material
helicoidally rolled around a central axis.
21. The paper roll of claim 20, wherein the at least one passive
element is placed at an interface between the at least two strips
of material.
22. The paper roll of claim 20, wherein the core comprises more
than one passive element and the passive elements are placed
symmetrically around the central axis of the roll such that, at any
point along the central axis of the roll, there is an equal angular
distance with respect to the central axis between passive elements
along a circumference of the roll.
23. The paper roll of claim 19, wherein the at least one passive
element is a copper wire.
24. The paper roll of claim 23, wherein the copper wire is 36 AWG
in size.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to paper roll
dispensers, for example for paper towels or toilet paper. More
precisely, the invention relates to a system and a method for
discriminating a roll in a paper roll dispenser, and a paper
roll.
BACKGROUND OF THE INVENTION
[0002] Several types of paper roll dispensers exist in the prior
art. These system provide gradually to a user of the dispenser
different types of paper rolled around an inner core (hereinafter
referred to as a "paper roll"). The most common of these dispensers
dispense paper items such as paper towels and toilet paper. These
dispensers are often used in public area washrooms.
[0003] An example of such a dispenser can be found in U.S. Pat. No.
6,293,486 (BYRD et al.). This document describes a dispenser
comprising an electronic system, which includes a network of at
least one photovoltaic cell which feeds a control circuit, which,
in turn, controls overall operation of the dispenser. The control
circuit reacts to a detection device, which detects variations in
light. The detection of a variation in the light activates the
distribution of a certain quantity of paper towels when an object,
such as the hand of a user, passes in front of the detection
device.
[0004] U.S. Pat. No. 6,412,679 (FORMON et al.) is also known in the
art and teaches a motorised dispenser which can distributed
individual paper towel segments from a paper roll. The dispenser
comprises a control device capable of detecting the presence of a
user, which activates the paper feeding device. The control device
is also used to control the amount of paper dispensed by preventing
distribution of paper if a certain portion of paper did not detach
itself properly from the roll.
[0005] U.S. patent application Ser. No. 2002/0096028 (MORAND) is
also known in the art and describes a paper towel distribution
apparatus comprising a paper roll support for the paper towels and
a cutting device pivotally mounted on an external peripheral part
of the paper roll. The cutting device can be placed between an
initial position where the sharp side of the cutting device is
positioned in proximity of the external peripheral part, and a
second position where the sharp side of the cutting device is moved
away from the paper roll support. In this second position, the
sharp side of the cutting device is positioned in a direction
generally opposite with respect to the paper roll support
rotational direction, such that any pulling force exerted by a user
on the paper towel distribution system will act against the sharp
side of the cutting device, thereby cutting a segment of paper
towel from the roll.
[0006] European patent application EP 1 232 715 discloses a paper
towel dispenser which has a capacitance-charge-based proximity
sensor. The proximity detector senses when a hand is placed near
the dispenser, and thereupon dispenses a set amount of towel. The
proximity sensor comprises a circuit according to a balanced bridge
principle wherein detection is based on detecting a phase
difference, which depends upon the amount of detected capacitance
difference or change.
[0007] Other systems in the prior art relate to paper roll
anti-theft protection devices. U.S. Pat. No. 6,653,940 teaches a
method and system for preventing the unauthorized removal of paper
rolls, such as cash register receipt paper rolls used by retailers,
as well as the anti-theft paper roll and methods of preparation
therefor. The method comprises affixing to the paper roll an
electronic sensor, wherein the sensor emits a detectable signal and
detecting the presence of the sensor when it passes through or near
a detection point at the retailers location. In one embodiment of
the invention, the sensor is an adhesive strip, affixed to the core
of the paper roll, wherein the core of the paper roll comprises a
flat surface integrally formed therein, onto which the sensor is
affixed.
[0008] Of course, several other documents describe generally paper
dispensers and these documents are known to the Applicant by the
following U.S. application and/or patent numbers: U.S. 2002/0019971
A1 (LEWIS et al.); U.S. 2002/0113109 A1 (GRACYALNY et al.); U.S.
2001/0032858 A1 (KAPILOFF, et al.); U.S. Pat. Nos. 6,439,502 B1
(GEMMEL et al.); 5,868,275 (MOODY, et al.); 5,820,231 (SCHN);
5,803,373 (SEDLOCK, JR. et al.); 5,452,832 (NIADA); 5,375,920
(MACCHI CASSIA); 5,375,785 (BOONE et al.); 5,294,192 (OMDOLL et
al.); 4,807,824 (GAINS et al.); 4,738,176 (CASSIA, et al.); and
3,948,715 (TOKUNO).
[0009] As shown above, certain prior art dispensers allow a
distribution of paper towels through light detection systems,
motion detectors and/or capacitance-change-based proximity sensors
capable of detecting the presence of a user near the dispenser.
[0010] However, it would be advantageous for several different
reasons, notably for reasons of quality control and a reduction of
maintenance and repair costs for dispensers, to develop a paper
roll dispenser which can only operate with paper rolls specifically
tailored for use in the dispenser. Thus, there is presently a need
for a type of dispenser which can reduce the occurrences of damages
caused to the dispenser through installation of an improper roll in
the dispenser.
SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to provide a system
and a method for discriminating a roll in a paper roll
dispenser.
[0012] It is also an object of the present invention to provide a
paper roll which can be discriminated.
[0013] According to the present invention, there is provided a
system for discriminating a roll placed in a paper roll dispenser,
comprising:
[0014] at least two conducting plates located within the paper roll
dispenser such that when the roll is positioned within the
dispenser, the plates are in proximity of the roll, the plates
being electrically insulated from each other;
[0015] means for detecting capacitance between the plates and
generating a signal indicative of the capacitance; and
[0016] means for discriminating said paper roll based on a value of
the signal.
[0017] According to the present invention, there is also provided a
method for discriminating a roll placed in a paper roll dispenser
comprising the steps of:
[0018] a) placing the roll in the dispenser;
[0019] b) providing at least two conducting plates located within
the paper roll dispenser such that when the roll is positioned
within the dispenser, the plates are in proximity of the roll, the
plates being electrically insulated from each other;
[0020] c) detecting capacitance between the plates;
[0021] d) generating a signal indicative of said capacitance;
and
[0022] e) discriminating said paper roll based on a value of the
signal.
[0023] According to the present invention, there is also provided a
paper roll comprising a core comprising at least one passive
element having an electrical conductivity different from that of
the core.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The present invention and its advantages will be more easily
understood after reading the following non-restrictive description
of preferred embodiments thereof, made with reference to the
following drawings in which:
[0025] FIG. 1 is a perspective view of a dispenser which includes a
system for discriminating a roll according to a preferred
embodiment of the invention showing the paper roll inserted in the
dispenser;
[0026] FIG. 2 shows a schematic perspective view of a paper roll
according to a preferred embodiment of the present invention;
[0027] FIG. 3 shows a partial perspective view of parts of the
system according to the present invention, in relation with parts
of the dispenser;
[0028] FIG. 4 shows a side view of what is shown in FIG. 3;
[0029] FIG. 5 shows a front view of what is shown in FIGS. 3 and
4;
[0030] FIG. 6 shows a perspective view of the components of the
according to the present invention;
[0031] FIG. 7 shows a schematic block diagram of components of the
system according to the present invention;
[0032] FIG. 8 shows a schematic representation illustrating the
relation between the plates according to the present invention and
a paper roll;
[0033] FIG. 9 shows a schematic representation illustrating the
relation between the plates according to the present invention and
a paper roll according to the present invention; and
[0034] FIG. 10 shows a graph illustrating voltages applied to the
conducting in relation to different paper rolls, versus time.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0035] As aforesaid and shown in FIGS. 1 and 7, it is an object of
the present invention to provide a system and a method for
discriminating a roll 12 in a paper roll dispenser 14. The system
for discriminating a roll 12 placed in a paper roll dispenser 14,
comprises at least two conducting plates 20 located within the
paper roll dispenser 14 such that when the roll 12 is positioned
within the dispenser 14, the plates 20 are in proximity of the roll
12. The plates 20 are electrically insulated from each other. The
system further comprises means for detecting capacitance between
the plates and generating a signal indicative of said capacitance
and means for discriminating the paper roll based on a value of the
signal. The plates 20 are in proximity of the roll 12 in that if
the roll comprises an element having an electrical conductivity
from that of the paper roll core, the capacitance measured between
the plates 20 is affected.
[0036] Preferably, as shown in FIGS. 3 to 6, the at least two, and
preferably four, conducting plates 20 are shaped and positioned in
an annular fashion in proximity of a roll support structure 22
within the dispenser 14.
[0037] Preferably, capacitance is detected between an individual
pair of adjacent plates 20 in a sequenced manner one pair after
another such that all combinations of capacitance between adjacent
conducting plates 20 are detected.
[0038] In accordance with a preferred embodiment and as shown in
FIG. 7, the means for detecting capacitance comprises means for
applying voltage between two adjacent plates 20. Preferably, the
means for applying voltage is included in an oscillator 26
operating at 4 KHz. The means for detecting capacitance also
comprises means for measuring voltage between two adjacent plates
20. Preferably, the means for measuring voltage is included in a
microprocessor 28 operating at 1 MHz. The means for detecting
capacitance also comprises control means for controlling the means
for applying and the means for measuring, in order to scan each
pair of plates 20 by sequentially applying the voltage between the
plates 20 of the pair during a given time period, and either
measuring the charge or discharge rate of voltage between the
plates 20 of the pair, said charge or discharge rate being
indicative of the capacitance. Preferably, the control means is
included in a microprocessor 28.
[0039] Preferably, the means for discriminating said paper roll
comprises comparing means which compares the signal resulting from
the charge and the discharge of the conducting plates to a
reference signal. Preferably, the comparing means is included in a
microprocessor 28 as shown in FIG. 7.
[0040] Preferably, the system according to the present invention
further comprises means for compensating the signal resulting from
the charge and the discharge of the conducting plates for changes
in an environment surrounding the system. Preferably, the means the
compensating is included in a microprocessor 28 as shown in FIG.
7.
[0041] Preferably, the system according to the present invention
further comprises means for detecting a placement of the roll in
the system. Preferably, the means for detecting are detection
switches 30a and 30b as shown in FIG. 7.
[0042] Preferably, the system according to the present invention
further comprises means for informing a user of results of an
assessment made by the means for discriminating. Preferably, the
means for informing the user comprises a green light 32a and a red
light 32b, either one being activated depending on the results of
the assessment made by the means for discriminating, as shown in
FIG. 7.
[0043] Preferably, the system according to the present invention
further comprises means for converting the charge or discharge rate
of voltage into a continuous voltage. Preferably, the means for
converting is located between the means for applying the voltage
and the means for measuring the voltage, such as between the
oscillator 26 and microprocessor 28 shown in FIG. 7.
[0044] Preferably, the system further comprises at least one
battery 34 to provide power to the system, a paper level switch 36
to indicate to the system the amount of paper left on the roll 12,
and a printed circuit board 38 as shown on FIGS. 3 to 6.
[0045] As aforesaid and shown in FIG. 2, it is also an object of
the present invention to provide a paper roll 12 which can be
discriminated.
[0046] As shown in FIG. 2 and according to the present invention,
the paper roll 12 comprises a core 50 comprising at least one
passive element 52 having an electrical conductivity different from
that of the core 50.
[0047] Preferably, the core 50 has a hollow cylindrical shape and
comprises at least two strips of material, preferably cardboard
helicoidally rolled around a central axis.
[0048] Preferably, the at least one passive element 52 is placed at
an interface between the at least two strips of material. Because
the strips are helicoidally rolled, the at least one passive
element 52 will also have a corresponding spiral shape.
[0049] In another preferred embodiment, the core 50 can comprise
more than one passive element 52. Preferably, the passive elements
52 are placed symmetrically around the central axis of the roll 12
such that, at any point along the central axis of the roll 12,
there is an equal angular distance with respect to the central axis
between passive elements 52 along a circumference of the roll 12
(e.g. 120 degrees between 3 elements, 180 degrees between two
elements).
[0050] Preferably, the system according to the present invention
comprises one additional conductive plate 20 compared to the number
of passive elements 52 in the core 50 of the roll 12 to be
discriminated. For example, if the core 50 comprises three passive
elements 52, the system should comprise four conductive plates 20.
Consequently, given the symmetry in the placement of the passive
elements 52, detection of a change in the capacitance between the
plates will occur between three pairs of plates out of the possible
four pairs of plates. By having more than one passive element in
the paper roll core, it is possible to further characterize the
roll in question.
[0051] Preferably, the at least one passive element 52 is a copper
wire and is 36 AWG in size. This material and size are chosen for
manufacturing consideration, since this type of wire is easily cut
by the saw which also cuts the strips that eventually form the
core.
[0052] The basic principle behind the detection of the passive
element 52 in the core 50 is the measurement of a change in
capacitance. In a preferred embodiment of the present invention,
the change in capacitance between a core having a passive element
and a core not having a passive element is of the order of 0.3 pF.
Preferably, the detection system comprises four conducting plates
20 shaped and positioned in an annular fashion in proximity of a
roll support structure 22 within the dispenser 14. When the means
for detecting a placement of the roll in the system 30a and 30b is
activated after an actual placement of a roll in the system, the
system is activated and measurements of capacitance between
adjacent conductive plates 20 are taken. The conductivity of the
passive element 52 in the core will have an effect of modifying the
frequency of the oscillator 26 connected to the different plates
20a, 20b, 20c and 20d as shown in FIG. 7. One after the other, the
microprocessor 28 will connect the oscillator 26 with the different
plates 20a, 20b, 20c and 20d and will store in its memory the
obtained frequency and will automatically compensate for any
changes in the environment of the system. In this manner, the
microprocessor 28 is able to clearly identify the model of the
paper roll product inserted into the dispenser 14. If the inserted
paper roll 12 corresponds to the desired model or type of product,
a green light 32a will be activated to indicate the validity of the
product. Otherwise, a red light 32b will be activated to indicate
that the inserted paper roll does not correspond to the desired
model.
[0053] Hence one element of novelty of the present invention
resides in the insertion in the core 50 of the paper roll 12 of a
passive element 52 having an electrical conductivity different from
that of the cardboard used during manufacturing of the core 50.
This passive element 52 constitutes a distinctive feature which
allows its detection and identification of the model of the paper
roll.
[0054] When the paper roll 12 is inserted in the dispenser 14, the
system according to the present invention validates the number of
distinctive elements present in the core 50 of the paper roll 12
and can then activate or not a locking system for the paper roll
12.
[0055] When the model of the paper roll 12 is considered to be
valid, the system will transition to an energy-saving mode, and no
other apparent event will occur except for the activation during a
short amount of time of the green light 32a to indicate the
validity of the paper roll 12.
[0056] Otherwise, the system can command means 40 so that the
dispenser cannot be used. During this operation, a red light 32b
will indicate during a short amount of time the non-conformity of
the paper roll 12.
[0057] In either case, whatever the type of paper roll 12 inserted
in the dispenser 14, the system will be activated and detect the
nature of the paper roll 12 upon sensing the insertion of a paper
roll 12 on the roll support structure 22 in the dispenser 14.
[0058] The measurement of the change of capacitance is based on the
principle of accumulation of energy between two conductive surfaces
separated by an insulating material. When voltage is applied to two
plates 20, electrical charges are blocked by the insulating
material between the plates 20 and accumulate, thereby creating a
voltage difference.
[0059] As shown in FIG. 8, the more the insulating material has
better insulating properties, the less charges can be transferred
from one plate 20a to another plate 20b and passage of charges 60
between the plates individually connected to the oscillator 26 is
hindered. Consequently, a voltage difference between the plates 20
can increase more rapidly since there is no loss of charges 60
between the plates 20 which are inserted around the plastic roll
support structure 22.
[0060] As shown in FIG. 9, by inserting a passive element 52 having
an electrical conductivity different from that of the paper roll
core 50 in FIG. 8, the insulating properties of the insulating
material between the two conductive plates 20 is affected. In a
preferred embodiment of the present invention, this passive element
52 is a copper wire. Hence, when a conducting material like the
copper wire is in proximity of the two plates, the passive element
52 creates a path facilitating the passage of charges 60 from one
plate to the other. This has the result of reducing the insulating
properties of the material between the plates and therefore
facilitates the passage of electrons. Consequently, the voltage
difference developed between the plates increases more slowly, in a
situation analogous to attempting to fill a bucket with water
compared to attempting to fill a bucket with water when there is a
hole in the bucket.
[0061] According to a preferred embodiment of the present
invention, the system comprises an oscillator 26 which applies a
voltage to the conducting plates 20. The plates will be charged in
a manner dependant on the quality of the insulating material which
will be affected by the presence or not of the passive element 52
in the paper roll core 50. As shown in FIG. 10, when the voltage
difference between the plates reaches a particular target level 64,
the oscillator 26 reverses itself and discharges the energy
accumulated between the plates 20. The better the insulating
properties of the material 66, the more rapidly the target voltage
level 64 is reached, and therefore the oscillatory action of the
oscillator is quicker. When the passive element 52 is present 68,
the loss of charges from one plate to the other is greater, hence
the time required for charging the plates and reaching the target
level voltage difference is increased, resulting in a lower
frequency. In FIG. 10, the target voltage level 64 is set to 100%
of the voltage supplied to the system. In a preferred embodiment of
the present invention, in order to reduce power consumption by the
system, the target voltage level is set at a lower percentage of
the voltage supplied to the system, e.g. 50%.
[0062] Preferably, an electronic component is inserted between the
oscillator 26 and the microprocessor 28 to convert the frequency
into a constant voltage. The level of this voltage is a function of
the frequency. If the frequency increases, the voltage will
increase accordingly. Preferably, the electronic component
comprises a low-pass filter having a cutoff frequency at 16 Hz.
[0063] As disclosed hereinabove in the Summary of the Invention, it
is also an object of the present invention to provide a method for
discriminating a roll in a paper roll dispenser, involving five
basic steps to which may be added a plurality of optional
steps.
[0064] The method for discriminating a roll in a paper roll
dispenser is preferably carried out using the following sequence of
steps:
[0065] a) placing the roll in the dispenser;
[0066] b) providing at least two conducting plates located within
the paper roll dispenser such that when the roll is positioned
within the dispenser, the plates are in proximity of the roll, the
plates being electrically insulated from each other;
[0067] c) detecting capacitance between the plates;
[0068] d) generating a signal indicative of said capacitance;
and
[0069] e) discriminating said paper roll based on a value of the
signal.
[0070] Preferably, the method further comprises the steps of:
[0071] detecting a placement of the roll in the system after step
a) and before step c); and
[0072] initiating step c) upon detection of the placement of the
roll in the system.
[0073] The method for discriminating a roll in a paper roll
dispenser is also preferably carried out using the following more
detailed sequence of steps, wherein:
[0074] step b) comprises the step of providing at least two
conducting plates shaped and positioned in an annular fashion in
proximity of a roll support structure within the dispenser;
[0075] step c) comprises the steps of
[0076] applying voltage between two adjacent plates of said plates;
and
[0077] measuring voltage between two adjacent plates of said
plates;
[0078] step d) comprises the steps of
[0079] scanning each pair of said plates by sequentially applying
the voltage between the plates of the pair during a given time
period, and either measuring the charge or discharge rate of
voltage between the plates of the pair to produce said signal;
and
[0080] compensating said signal for changes in an environment
surrounding the system;
[0081] and
[0082] step e) comprises the steps of
[0083] comparing said signal to a reference signal to obtain an
assessment of the signal;
[0084] converting said assessment signal into a continuous voltage;
and
[0085] informing a user of results based on the continuous
voltage.
[0086] Although the present invention has been explained
hereinabove by way of a preferred embodiment thereof, it should be
pointed out that any modifications to this preferred embodiment
within the scope of the appended claims is not deemed to alter or
change the nature and scope of the present invention.
* * * * *