U.S. patent application number 11/577200 was filed with the patent office on 2008-10-23 for tinting machine system.
Invention is credited to Ian David Oakes.
Application Number | 20080257446 11/577200 |
Document ID | / |
Family ID | 33462674 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080257446 |
Kind Code |
A1 |
Oakes; Ian David |
October 23, 2008 |
Tinting Machine System
Abstract
A tinting machine system for tinting base paint supplied in a
container which base paint is suitable for use in a tinted coating
composition so as to produce a tinted coating composition, the
tinting machine system comprising a tinting machine and processing
means, the tinting machine having a colourant dispenser system
comprising an actuator able to dispense a pre-determined amount of
at least one colourant into the container, and weighing means able
to weigh the container to determine an actual dispensed weight of
each individual colourant and/or an actual total dispensed weight,
the processing means able to compare the actual dispensed weight of
each individual colourant and/or the actual total dispensed weight,
with a correct weight for the tinted coating composition stored in
the processing means for each dispensed tinted coating composition,
the processing means comprising statistical analysis means to
statistically analyse the actual dispensed weight of each
individual colourant and/or the actual total dispensed weight for
each dispensed tinted coating composition so as to calculate a
colourant weight dispenser error value for each colourant dispenser
system, thereby enabling any colourant dispenser system causing
concern to be identified.
Inventors: |
Oakes; Ian David;
(Berkshire, GB) |
Correspondence
Address: |
THE GLIDDEN COMPANY
15885 WEST SPRAGUE ROAD
STRONGVILLE
OH
44136
US
|
Family ID: |
33462674 |
Appl. No.: |
11/577200 |
Filed: |
September 30, 2005 |
PCT Filed: |
September 30, 2005 |
PCT NO: |
PCT/EP05/10634 |
371 Date: |
November 19, 2007 |
Current U.S.
Class: |
141/1 ; 141/104;
141/94 |
Current CPC
Class: |
B01F 15/0445 20130101;
G01G 17/06 20130101; B01F 13/1055 20130101; B01F 2215/005 20130101;
B01F 13/1063 20130101 |
Class at
Publication: |
141/1 ; 141/104;
141/94 |
International
Class: |
B65B 1/04 20060101
B65B001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2004 |
GB |
0422787.2 |
Claims
1. A tinting machine system for tinting base paint supplied in a
container which base paint is suitable for use in a tinted coating
composition so as to produce a tinted coating composition, the
tinting machine system comprising a tinting machine and processing
means, the tinting machine having a colourant dispenser system
comprising an actuator able to dispense a pre-determined amount of
at least one colourant into the container, and weighing means able
to weigh the container to determine an actual dispensed weight of
each individual colourant and/or an actual total dispensed weight,
the processing means able to compare the actual dispensed weight
of: a) each individual colourant, b) the actual total dispensed
weight, or c) both with a correct weight for the tinted coating
composition stored in the processing means for each dispensed
tinted coating composition, the processing means comprising
statistical analysis means to statistically analyse: a) the actual
dispensed weight of each individual colourant b) the actual total
dispensed weight for each dispensed tinted coating composition, or
c) both so as to calculate a colourant weight dispenser error value
for each colourant dispenser system, thereby enabling any colourant
dispenser system causing concern to be identified.
2. A tinting machine system according to claim 1 in which a defined
relationship exists between the amount of colourant dispensed and a
given actuator input, and the processing means is able to correct
the defined relationship to compensate for the colourant weight
dispenser error value for any colourant dispenser system causing
concern.
3. A tinting machine system according to claim 1 in which the
correct weight for the tinted coating composition is a total weight
for that particular tinted coating composition, individual
colourant weights for that particular tinted coating composition,
or both.
4. A tinting machine system according to claim 1 in which the
tinted coating composition includes more than one colourant,
selected from the group of a) each colourant is dispensed
substantially simultaneously, and the weighing means is able to
weigh the container to determine the actual total dispensed weight;
or b) each colourant is dispensed sequentially, and the weighing
means is able to weigh the container to determine the actual
dispensed weight of: i) each individual colourant, ii) the actual
total dispensed weight, or iii) both.
5. A tinting machine according to claim 2 in which the tinted
coating composition includes more than more than one colourant,
selected from the group of a) each colourant is dispensed
substantially simultaneously, and the weighing means is able to
weigh the container to determine the actual total dispensed weight;
or b) each colourant is dispensed sequentially, and the weighing
means is able to weigh the container to determine the actual
dispensed weight of each individual colourant, the actual total
dispensed weight, or both.
6. A tinting machine system according to claim 1 in which the
processing means is remote from the tinting machine.
7. A tinting machine system according to claim 1 in which the
processing means is able to determine if the colourant weight
dispenser error value associated with each colourant dispenser
system is within an acceptable range.
8. A tinting machine system according to claim 7 in which the
processing means includes signal means capable of sending a signal
to the tinting machine to adjust the colourant dispenser system so
that it restored within the acceptable range.
9. A tinting machine system according to claim 8 in which the
signal means automatically sends the signal to the tinting machine
when the error value is outside the acceptable range.
10. (canceled)
11. A tinting machine system according to claim 1 in which the
colourant weight dispenser error value error is at least partially
caused by changes in efficiency of the colourant dispenser system,
ranging from changes in efficiency of a gear pump of the colourant
dispenser system caused by wear of the gear pump.
12. A tinting machine system according to claim 1 in which at least
a number of dispensed tinted coating compositions substantially
equal to twenty multiplied by the number of colourant dispenser
systems is required before each colourant dispenser system is
adjusted.
13. A tinting machine system according to claim 1 in which, for
sixteen colourant dispenser systems, at least three hundred
dispensed tinted coating compositions are required before each
colourant dispenser system is adjusted.
14. A tinting machine system according to claim 1 in which the
statistical analysis means is able to calculate a confidence level
for each colourant weight dispenser error value.
15. A tinting machine system according to claim 14 in which the
colourant dispenser system is adjusted when the associated
confidence level is above a predetermined level.
16. A tinting machine system according to claim 1 in which the
statistical analysis means is software which employs regression
analysis to calculate the colourant weight dispenser error
value.
17. A tinting machine according to claim 1 in which the processing
means comprises a first processing means, and a second processing
means.
18. A tinting machine system according to claim 17 in which the
second processing means is remote from the tinting machine,
19. A tinting machine system according to claim 1 in which the
tinting machine is an in-store tinting machine suitable for use by
in-store machine operators.
20. A method for detecting errors of weight of colourant dispensed
in a process for tinting base paint supplied in a container which
base paint is suitable for use in a tinted coating composition so
as to produce a tinted coating composition, comprising the steps
of: dispensing a pre-determined amount of at least one colourant
from a colourant dispenser system, the pre-determined amount being
appropriate to the achievement of the tinted coating composition,
into a pre-determined type and volume of a base paint, weighing the
container to determine an actual dispensed weight of: a) each
individual colourant, b) an actual total dispensed weight, or c)
both; and statistically analysing the actual dispensed weight of:
a) each individual colourant b) an actual total dispensed weight,
or c) both so as to calculate a colourant weight dispenser error
value for each colourant dispenser system, thereby enabling any
colourant dispenser system causing concern to be identified.
21. A method according to claim 20 in which a defined relationship
exists between the amount of colourant dispensed and a given
actuator input, and the defined relationship is correctable to
compensate for the colourant weight dispenser error value for any
colourant dispenser system causing concern.
22. A method according to claim 20 in which the tinted coating
composition includes more than one colourant, selected from the
group of a) each colourant is dispensed substantially
simultaneously, and the container is weighed to determine the
actual total dispensed weight; or b) each colourant is dispensed
sequentially, and the weighing means is able to weigh the container
to determine the actual dispensed weight of: i) each individual
colourant, ii) the actual total dispensed weight or iii) both.
23. A method according to claim 21 in which the tinted coating
composition includes more than more than one colourant, selected
from the group of a) each colourant is dispensed substantially
simultaneously, and the container is weighed to determine the
actual total dispensed weight; or b) each colourant is dispensed
sequentially, and the container is weighed to determine the actual
dispensed weight of each individual colourant, the actual total
dispensed weight, or both.
24. A method according to claim 20 in which the colourant weight
dispenser error value is compared to an acceptable range to
determine if it is within the acceptable range.
25. A method according to claim 24 in which the colourant dispenser
system is adjusted so that it is within the acceptable range.
26. A method according to claim 25 in which the colourant dispenser
system is automatically adjusted.
27. A tinting machine system according to claim 1 in which the
coulorant is a liquid colourant.
28. A method according to claim 20 wherein the colourant is a
liquid colourant.
29. A tinting machine system according to claim 17 in which the
second processing means prevents any difference between the actual
colourant dispensed weight and the correct weight which is outside
a predetermined range from being subject to statistical
analysis.
30. A method according to claim 21 in which the colourant weight
dispenser error value is compared to an acceptable range to
determine if it is within the acceptable range.
31. A tinting machine system for tinting base paint supplied in a
container which base paint is suitable for use in a tinted coating
composition so as to produce a tinted coating composition, the
tinting machine system comprising a tinting machine and processing
means, the tinting machine having a colourant dispenser system
comprising an actuator able to dispense a pre-determined amount of
at least one colourant into the container, and weighing means able
to weigh the container to determine an actual dispensed weight of
each individual colourant and/or an actual total dispensed weight,
the processing means, comprises a first processing means, and a
second processing means, optionally remote from the tinting
machine, able to compare the actual dispensed weight of: a) each
individual colourant, b) the actual total dispensed weight, or c)
both with a correct weight for the tinted coating composition
stored in the processing means for each dispensed tinted coating
composition, the processing means comprising statistical analysis
means to statistically analyse: a) the actual dispensed weight of
each individual colourant, b) the actual total dispensed weight for
each dispensed tinted coating composition, or c) both so as to
calculate a colourant weight dispenser error value for each
colourant dispenser system, thereby enabling any colourant
dispenser system causing concern to be identified; and wherein a
defined relationship exists between the amount of colourant
dispensed and a given actuator input, and the processing means is
able to correct the defined relationship to compensate for the
colourant weight dispenser error value for any colourant dispenser
system causing concern; and wherein the correct weight for the
tinted coating composition is a total weight for that particular
tinted coating composition, individual colourant weights for that
particular tinted coating composition, or both; and wherein the
tinted coating composition includes more than one colourant,
selected from the group of a) each colourant is dispensed
substantially simultaneously, and the weighing means is able to
weigh the container to determine the actual total dispensed weight;
or b) each colourant is dispensed sequentially, and the weighing
means is able to weigh the container to determine the actual
dispensed weight of: i) each individual colourant, ii) the actual
total dispensed weight, or iii) both; and wherein the correct
weight for the tinted coating composition is a total weight for
that particular tinted coating composition, and/or individual
colourant weights for that particular tinted coating composition;
and wherein the processing means is able to determine if the
colourant weight dispenser error value associated with each
colourant dispenser system is within an acceptable range; and
wherein the second processing means prevents any difference between
the actual colourant dispensed weight and the correct weight which
is outside a predetermined range from being subject to statistical
analysis; and wherein the colourant weight dispenser error value
error is at least partially caused by changes in efficiency of the
colourant dispenser system, ranging from changes in efficiency of a
gear pump of the colourant dispenser system caused by wear of the
gear pump; and wherein at least a number of dispensed tinted
coating compositions substantially equal to twenty multiplied by
the number of colourant dispenser systems is required before each
colourant dispenser system is adjusted; and wherein the statistical
analysis means is able to calculate a confidence level for each
colourant weight dispenser error value through software which
employs regression analysis to calculate the colourant weight
dispenser error value; and wherein the colourant is a liquid
colourant.
Description
[0001] The present invention relates to a tinting machine system
for tinting base paints, and to a method of detecting errors of
weight of individual colourant dispensed in a process for tinting
base paints.
[0002] Paint or similar coating compositions such as lacquers,
varnishes or wood stains, is used by both the skilled professional
decorator and the relatively unskilled do-it-yourself painter for a
variety of reasons. Typically, these are to brighten up the
surroundings and/or to match the colour of a particular item of
furniture, floor or wall covering, and other surfaces found in
buildings. As consumers have become increasingly sophisticated and
individual in their choice of colours, the demand for a wider range
of colours has also increased. This presents a problem to the paint
manufacturer and the retailer or trade store keeper as the former
has to produce many colours in small amounts, thus losing the
economies of scale and, of course the retailer or store keeper has
to provide additional space to store and display this plurality of
coloured paints. A typical paint would be architectural paint used
on site at ambient temperatures.
[0003] Some paint manufacturers have addressed this problem by
developing tinting machines. These operate on the basis that a
variety of colours can be made by adding colourant to a factory
produced base paint at the retailer's premises. Such machines are
referred to as in-store tinting machines. A small number of
different coloured base paints, comprising three or four spanning
the range of light to deep shades, is provided by the supplier to
the retailer, in cans. Such a base paint is unfinished from the
point of view of the final colour.
[0004] The further colourant to be added is usually in the form of
pigments, pigment concentrates, tinters or dyes. Usually, about
twenty such colourants are required to produce the full colour
range of paints, although only frequently three or four are
required to produce any given colour. The colourants are added to
the base paint according to a predetermined recipe, being one of
many, stored in a computer. The recipe also indicates which of the
base paints should be selected for tinting in order to produce the
required colour.
[0005] Such tinting machines typically comprise a number of storage
vessels containing the colourants, a means of delivering the
colourant to the can of base paint, for example by one or more
manual or automated piston or gear pumps, storage means for the
collection of recipes and control means (manual and/or
computerised) for controlling the delivery of colourant in
accordance with the selected recipe. The control means may, for
example, control the addition of colourant by governing the
traverse of pistons in pumps or by activating the pumps for a
predetermined time period so that a predetermined volume of
colourant is delivered in accordance with the recipe for the
selected colour. In this way varying amounts of each colourant may
be added to the selected base paint enabling paints of a variety of
alternative colours to be produced. Finally, the base paint and
added colourant are subjected to mixing, usually by intense
shaking, to obtain a homogeneous mixture of base paint and
colourant with even colour.
[0006] The problem with such tinting machines, however is that the
actual colour of the final paint depends critically on the amount
of each of the colourants added to the base paint. For example,
where a colourant is added using a pump driven by a motor, the
number of turns or steps of the motor relates to a quantity of
colourant to be added. This relationship is determined by
measurements taken at the time of assembly of the machine and is
used to calibrate the pumps.
[0007] However, for various reasons, this calibration can change
over time. For example, because pigments are generally very hard
materials, the pump mechanism will wear with use, resulting in
additions being made which are not in accordance with the recipe.
Even when the pumps are operating correctly the incorrect amount of
colourants may be added, if, for example the nozzles through which
the colourants exit into the can of base paint are partially or
fully blocked. In larger retail stores, the high use rate can
result in the tinting machine going out of calibration within a few
weeks. This results in a mis-tint causing the resulting paint to be
other than the specified colour and consequently discarded. Even
worse is when the variation from the recipe is small and the
mis-tint passes unnoticed until the paint has been applied. This
inevitably requires a surface to be repainted with the intended
colour causing additional expense and inconvenience. Other causes
of mis-tinting are many and include defective pumps, leaky pipework
and empty tinter vessels.
[0008] Since the tinting machines are designed to produce many
different colours, it is very difficult for the operator to
recognise simply by looking at the most recently mixed paint when a
particular colour has been incorrectly tinted. Consequently, many
colours may be mis-tinted before it comes to the operator's
attention.
[0009] Tinting machines are known where the container of a tinted
coating composition is weighed, for example using a load cell,
before and after a particular tint, which generally comprises more
than one colourant, has been dispensed into the container, thus
enabling the total actual weight of colourant dispensed for that
particular tint to be calculated. The actual weight is then
compared to a correct weight which is stored in the collection of
colour recipes, and an error signal generated if the difference
between the actual and correct weights is outside a predetermined
acceptable range. Such a signal alerts the machine operator to a
mis-tint who can then take appropriate action. This data can also
be monitored to give an indication of the general state of repair
of the tinting machine.
[0010] However, in such tinting machines it is not possible to
determine the degree to which each colourant dispensed contributes
to the overall error, since each tint comprises several, typically
three or more, colourants. Thus whilst it is known that there is an
error associated with a particular tint, it is not possible to
determine which particular colourant or colourants is causing the
error, and adjust accordingly.
[0011] In tinting machines, the colourant can be dispensed either
simultaneously, or sequentially.
[0012] In simultaneously dispensing machines, each of the
colourants required to be added to the base paint to achieve the
desired colour of coating composition is added separately, but
substantially simultaneously, for example by the number of turns of
the pump motor. In the case of simultaneous dispensing it is
impossible to either check that the individual colourant has been
added accurately, or indeed control the addition of each colourant
by, for example, weighing the container.
[0013] In sequentially dispensing machines, each of the colourants
required to be added to the base paint to achieve the desired
colour of coating composition is added one after the other, using a
pump driven by a motor.
[0014] In both sequentially and simultaneously dispensing tinting
machines a maintenance engineer calibrates individual colourant
dispenser systems by manually dispensing colourant from each
dispenser for a range of number of turns of the pump, which in turn
corresponds to a number of motor steps, so as to generate a
calibration curve, typically a straight line, which mathematically
equates the number of steps of the motor required to dispense a
known quantity of colourant. Based on this calibration curve, it is
possible to select a required quantity of colourant for a
particular tint, and know how many steps of the motor are required
to dispense such a quantity.
[0015] To check the calibration is correct, i.e. to establish that
the quantity of colourant dispensed corresponds to the number of
steps of the motor, the maintenance engineer can repeat the
calibration process to generate a new curve. A large discrepancy
between the two curves might indicate that there is a problem with
a component of the colourant dispenser system, for example, the
pump is worn to such an extent that it needs replacing.
[0016] It can be seen that this is a very laborious process, and
requires a maintenance engineer to be in attendance. Furthermore,
it would require the tinting machine being unavailable for customer
use for a considerable period of time, and finally such a procedure
is a manual process and is therefore sensitive to operator error.
Clearly this is not an efficient means of maintaining the tinting
machine, and is therefore undesirable.
[0017] An object of the present invention is to provide a tinting
machine system which can be maintained more efficiently.
[0018] According to the present invention there is provided a
tinting machine system for tinting base paint supplied in a
container which base paint is suitable for use in a tinted coating
composition so as to produce a tinted coating composition, the
tinting machine system comprising a tinting machine and processing
means, the tinting machine having a colourant dispenser system
comprising an actuator able to dispense a pre-determined amount of
at least one colourant into the container, and weighing means able
to weigh the container to determine an actual dispensed weight of
each individual colourant and/or an actual total dispensed weight,
the processing means able to compare the actual dispensed weight of
each individual colourant and/or the actual total dispensed weight,
with a correct weight for the tinted coating composition stored in
the processing means for each dispensed tinted coating composition,
the processing means comprising statistical analysis means to
statistically analyse the actual dispensed weight of each
individual colourant and/or the actual total dispensed weight for
each dispensed tinted coating composition so as to calculate a
colourant weight dispenser error value for each colourant dispenser
system, thereby enabling any colourant dispenser system causing
concern to be identified.
[0019] According to another aspect of the present invention there
is provided a method for detecting errors of weight of colourant
dispensed in a process for tinting base paint supplied in a
container which base paint is suitable for use in a tinted coating
composition so as to produce a tinted coating composition,
comprising the steps of dispensing a pre-determined amount of at
least one colourant from a colourant dispenser system, the
pre-determined amount being appropriate to the achievement of the
tinted coating composition, into a pre-determined type and volume
of a base paint, weighing the container to determine an actual
dispensed weight of each individual colourant and/or an actual
total dispensed weight, and statistically analysing the actual
dispensed weight of each individual colourant and/or an actual
total dispensed weight so as to calculate a colourant weight
dispenser error value for each colourant dispenser system, thereby
enabling any colourant dispenser system causing concern to be
identified.
[0020] By analysing the actual dispensed weight and the correct
weight for each dispensed tinted coating composition, whether the
colourant is simultaneously or sequentially dispensed, it is
possible to determine a colourant weight dispenser error value for
each colourant dispenser system by using the actual dispensed
weight generated in the course of the tinting machines normal use,
i.e. without having to shut the machine down, by which is meant
preventing consumers from obtaining tinted coating compositions
from the machine rather than turning the machine off.
[0021] Furthermore, it is not necessary for a maintenance engineer
to manually inspect each colourant dispenser system to identify any
problems. In addition, the individual colourant dispenser system
can then be adjusted if necessary so as to dispense the correct
quantity of colourant.
[0022] This is clearly a more efficient procedure in comparison to
the maintenance engineer manually dispensing known quantities of
colourant. By identifying the colourant dispenser system of
concern, in the event that the maintenance engineer is required to
inspect the machine, considerable time is also saved due to the
fact that the colourant dispenser system has already been
identified.
[0023] In the case where the tinting machine is adjusted remotely
either automatically or by a computer operator, i.e. not at the
location of the tinting machine which is typically in a retail
store, it may not be necessary for a maintenance engineer to visit
at all. Furthermore, if the tinting machine is not adjusted
remotely, the fact that adjustment required itself can be
determined remotely enables a tinting machine operator to carry out
the adjustment locally, without the need for a maintenance
engineer. This would not be possible in the case where the error
associated with individual colourant dispenser systems is not
known, since it is not possible to adjust the tinting machine as a
whole, but only individual colourant dispenser systems.
[0024] Thus, it can be seen that the present invention not only
reduces the time the machine is out of calibration, thereby
reducing the likelihood of mis-tints, but also minimises the
requirement for maintenance engineer visits, and in the case where
a visit is required less time is spent analysing the machine since
the colourant dispenser system at fault has already been
identified.
[0025] The present invention will now be described by way of
example only with reference to the accompanying drawings, in
which:
[0026] FIG. 1 is a diagrammatic representation of a tinting machine
system, and
[0027] FIG. 2 is a schematic representation of the colourant
dispenser systems of the tinting machine of FIG. 1.
[0028] With reference to FIGS. 1 and 2 there is shown a tinting
machine system 20 comprising a tinting machine 22, processing means
in the form of a first personal computer 24, and a second personal
computer 26. The tinting machine 22 is an in-store tinting machine,
typically used in retail store outlets to enable consumers to
purchase tinted coating compositions. Paint containers of all sizes
are used, typically those sizes used by consumers when purchasing
paint that is not mixed in store. However, the size of the
container is not limited to such sizes, but to sizes which are
capable of being prepared in an in-store tinting machine. It is
also to be understood that tinting machines also includes machines
that are located in environments not accessible by the consumer,
for example, in a contractor's warehouse.
[0029] The first personal computer 24 stores a collection of colour
recipes which includes information indicating which base paint to
select for tinting, the amount of each colourant addition to be
made and the final weight of the container of tinted paint for each
tinted coating composition. The amount of colourant addition may be
by weight or volume. The colours may be identified by name, code or
cypher or combinations thereof, for example British Standard or RAL
names or codes, NCS (Natural Colour System), NCS2, or "Dulux"
"Colour Palette" cyphers. The collection of colour recipes can be
recorded in various forms including a compilation or a database.
Preferably they are recorded systematically or methodically and are
individually accessible to form a database which enables additions
and deletions to be more readily made. In this embodiment, the
collection of recipes can be stored directly onto the hard drive of
the first personal computer 24, alternatively other storage means,
such as floppy disks, optical disks such as a CD-ROM and Digital
Versatile Disk (DVD) may be used.
[0030] The first personal computer 24 also has software installed
which enables both control of the tinting machine 22, and analysis
of the weights of the dispensed tinted coating composition. The
first personal computer 24 is further connected to a video display
25 to which messages can be signalled and displayed.
[0031] In this embodiment, the first personal computer 24 is
directly connected to the tinting machine 22 via a cable 21. In an
alternative embodiment, the first personal computer may stand
alone, in which case it may communicate with the tinting machine
from a remote location via a phone line, across a network, or any
other suitable connection.
[0032] The second personal computer 26 is remote from the tinting
machine 22 and is connected to the tinting machine using a phone
line 28 which connects via the first personal computer 24. The
second personal computer 26 includes statistical analysis software
which analyses data collected from the tinting machine (see below).
In another embodiment the second personal computer can be connected
to the tinting machine via a network connection, the internet, or
any other suitable connection.
[0033] In an alternative embodiment the first and second personal
computers could be integrated into a single processing means, with
the single processing means being local to, either integrated with
or stand alone, or remote from the tinting machine. In the case
where the single processing means is remote from the tinting
machine, it will be necessary to provide further processing means
proximate the tinting machine to enable it to be controlled by a
machine operator.
[0034] The tinting machine 22 includes sixteen colourant dispenser
systems 30 (only one of which is shown in FIG. 1). Each colourant
dispenser system 30 includes a storage vessel 32 which contains
colourant 34. FIG. 2 shows that each of the colourant dispenser
systems 30 (numbered 1 to 16) is connected to a common dispensing
nozzle 36 via pipework 38. Each colourant dispenser system 30
includes a pump 40 which is driven by an actuator in the form of a
stepper motor 42. Each stepper motor 42, and thus the dispensing of
individual colourants 34, is controlled by the first personal
computer 24. To dispense the required amount of colourant for the
particular coating composition, the stepper motor 42 is operated so
as to turn the pump 40 a specified number of turns. In this
embodiment, the pumps and motors are identical for each colourant
dispenser system. Alternatively, different sized pumps and motors
could be used for each colourant dispenser system depending on the
requirement of that system.
[0035] In this embodiment, the addition of colourant to the base
paint is carried out using a pump driven by a stepper motor. In
other embodiments a piston type arrangement may be used instead of
a pump, or a syringe driven by a motor. Stepper motors are
preferred as they can be accurately controlled thereby delivering
precise quantities of colourant via the pump. Alternatively, a
standard motor and an encoder can perform the same function as the
stepper motor.
[0036] In this embodiment, where more than one colourant is
required to achieve the tinted coating composition the colourants
are added substantially simultaneously so as to reduce the overall
dispensing time. In an alternative system, the colourants can be
added sequentially, i.e., one after the other.
[0037] Whilst in this embodiment sixteen colourants are used, any
number of colourants may be used, although typically, between nine
and thirty two colourants are used. Increasing the number of
colourants may increase the number of tints available, but will add
to the complexity of the tinting machine.
[0038] Suitable colourants include pigments, pigment concentrates
and dyes. Pigment concentrates generally comprise high levels of
pigment, dispersed in a carrier liquid, optionally with the aid of
dispersant. The carrier liquid may be an organic solvent or water
or mixtures thereof. Solutions of dyes in appropriate solvents or
undiluted dyes are also useful. Pigment concentrates are preferred
for paints as they provide better hiding power than dyes. It is to
be understood that the present invention can use any suitable
colourants or carrier liquids, and is not limited to those examples
given. Other examples include water based pigment dispersions, or
resin based pigment dispersions carried in solvents. It will also
be appreciated that the present invention is not limited to the use
of liquid colourants, with dry colourants, for example colourants
in the form of solid tinters, also envisaged.
[0039] FIGS. 1 and 2 shows a base paint container 44 part cut away
to reveal that it is almost fully filled with base paint 46
situated on weighing means in the form of a load cell 48. The load
cell 48 is connected to an analogue to digital converter (ADC) 50,
which signals in digital format any weight registered by the load
cell 48 to the first personal computer 24.
[0040] A load cell is a device which produces an output signal
proportional to the applied weight or force when that weight or
force is within the range of operation of that device. Load cells
are the preferred form of weighing means for this application since
they are better able to register a wide range of weights
accurately. This is important since light colours require a small
addition of colourant to the base paint, and deep colours typically
require significantly more colourant to be added. However, other
weighing means are also envisaged which are similarly able to
register such a wide range of weight accurately.
[0041] The nozzle 36 is located vertically above open mouth 37 of
the container so that additions of colourant can be conveniently
made to the base paint.
[0042] The base paint 46 comprises all the necessary components of
a coating composition including pigment, binder, carrier liquid,
solvent, dispersant, antifoam, coalescing aid and other additives
typically found in coating compositions. The base paint is
distinguished from the final tinted coating composition mainly
because it does not contain all of the required colourants to
produce a specified colour contained in the collection of colour
recipes. The number of base paints required for a particular
product, for example a finish such as matt emulsion, ranges,
typically, from one to eight is generally from three to eight, and
preferably from four to six are used as this reduces the risk of
selecting the wrong base paint for tinting whilst maintaining
acceptable capability in producing the necessary range of
colours.
[0043] The tinting machine system is operated as follows:
[0044] A consumer will firstly select a desired tint, sheen, for
example matt, silk, or gloss, and container volume, which is
communicated to the machine operator. Each selection will have a
code which corresponds to a particular colour recipe stored on the
computer. The selection is inputted into the first personal
computer 24 by the machine operator, and the computer will
determine firstly, which combination of colourants are required,
and in what quantity for the selected container volume, and
secondly which base paint is required. In another embodiment, the
tinting machine could be a self-service machine where the selection
is inputted directly by the consumer.
[0045] The machine operator will position the correct base paint
container 44 under the dispensing nozzle 36, and then activate the
tinting machine 22 via the first personal computer 24 such that the
stepper motor 42 drives the pump 40 of each appropriate colourant
dispenser system 30, and dispenses the colourant 34 into the paint
container 44 via nozzle 36 to produce a tinted coating composition.
After all the colourants required have been dispensed, the
container 44 is shaken to ensure a homogeneous mix.
[0046] The software installed in the first personal computer 24
controls the tinting machine so that the paint container 44 is
weighed before dispensing colourant, and after all the colourants
required have been dispensed. The total actual weight of colourants
dispensed can then be calculated for the dispensed tinted coating
composition, i.e. the combined weight of colourants, not specific
colourant weights. The first personal computer 24 also stores both
the correct weight of individual colourants which should have been
dispensed for that particular tinted coating composition, and the
correct weight of the tinted coating composition (including all
ingredients) this being based on the colour recipe and the volume
of the paint container. The correct weights and the actual weight
for the particular tinted coating composition is then logged on the
first personal computer.
[0047] If the difference between the correct weight for the tinted
coating composition and the actual weight for the dispensed coating
composition is outside an acceptable range, typically a ten percent
deviation from the correct value, then the machine operator is
warned via the display unit 25 that a mis-tint has occurred, and
appropriate action can be taken, typically re-dispensing the
coating composition.
[0048] In the event the difference between the correct and actual
weights is outside a predetermined range, i.e. a range considered
to be typical for errors due to incorrect quantities of colourant
being dispensed, the machine operator is also alerted. This
difference is typically as a result of operator error. In such
circumstances, whilst the machine operator is alerted to such an
error, and such weight data is logged on the first personal
computer, it is not used in the statistical analysis of the data
since the error is not attributable to the quantity of colourant
dispensed, and therefore not relevant in determining errors
attributable to the colourant dispenser system.
[0049] The above procedure is repeated as more consumers request
tinted coating compositions, with the actual and correct weight of
the tinted coating compositions being logged. It will be
appreciated that over a period of time, data is collected for
different tinted coated compositions, i.e. compositions which use
different numbers and combinations of colourants.
[0050] The actual and dispensed weight data for each dispensing
coating composition (apart from those ignored as detailed above) is
accessed by the second personal computer 26 via the phone line 28.
It is also possible to use a network connection 28 or the internet
to access the data, or the data can be transferred manually to the
second personal computer 26 via storage media such as, for example,
a CD-ROM.
[0051] The statistical analysis software installed in the second
personal computer 26 analyses the logged actual and correct weight
for each dispensed coating system by firstly calculating the
difference between the actual and correct weight data. Each
dispensed coating composition will comprise, in addition to the
base paint, for example three colourants, and therefore the
difference between the actual and correct weighs is attributable to
influences from the three colourant dispenser systems, typically
but not limited to wear of the pump associated with each system.
Thus the difference is essentially due to, in this case, three
factors. It will be appreciated that mis-tints are caused by other
factors in the colourant dispenser system, for example, blockages,
and that the present invention can be used to identify the
differences caused by these factors.
[0052] A least squares regression analysis is a known statistical
analysis technique, by which it is possible to determine the effect
of individual factors on an overall result which is influenced by
those factors. In this case, the individual parameters are the
individual colourants dispensed for each dispensed tinted coating
composition, and the overall result is the difference between the
actual and correct weight of the dispensed tinted coating
composition. Thus, by employing least squares regression analysis
on the logged actual and correct weights for a number of dispensed
coating compositions, the influence of each colourant dispenser
system on the difference is calculated, and thus a colourant weight
dispenser error value for each colourant dispensing system is
determined.
[0053] The colourant weight dispenser error value is a percentage
deviation (positive or negative) from a correct value of colourant
which should have been dispensed, this correct value being
determined from an initial calibration curve generated manually by
a maintenance engineer. Typically, the initial calibration curve is
a straight line governed by the relationship y=mx+c, y being equal
to the number of motor steps, x being equal to the quantity of
colourant, and m being the gradient of the curve. The intercept c
allows for the fact that, in some cases, a certain number of motor
steps are required before any colourant is dispensed. Thus, based
on this relationship, the number of motor steps to dispense a
required amount of colourant is known. This data is stored on the
first personal computer.
[0054] An error value of -e% means that the particular colourant
dispenser system is dispensing e% less colourant than the initial
calibration curve suggested, and therefore to dispense the correct
amount of colourant, the initial calibration curve can be adjusted
taking into account the error value of -e% to generate a new
calibration curve. More specifically, the new calibration curve
will be of the form, y=(m+e)x+c to reflect the new relationship
such that to dispense the correct of amount of colourant more steps
of the motor are required.
[0055] Conversely, an error value of +e%, means that more colourant
is being dispensed, and therefore the new calibration curve will be
of the form, y=(m-e)x+c to reflect the new relationship such that
to dispense the correct of amount of colourant less steps of the
motor are required.
[0056] Before adjusting the calibration curve, the software
installed in the second personal computer 26 compares the colourant
weight dispenser error value for each colourant dispenser system to
an acceptable range for that system. For example, error values
within ten percent may be considered acceptable, and therefore no
adjustment will be made unless the error value is more than ten
percent above or below the correct value based on the initial
calibration. In the event that the error value is outside the
acceptable range, the calibration between the number of motor steps
and quantity of colourant is adjusted such that a given input to
the stepper motor will dispense the correct amount of colourant.
Clearly, the acceptable range can be set accordingly.
[0057] The software on the second personal computer 26 can be
programmed such that the adjustments are made automatically, for
example, if the colourant weight dispenser error value is outside
the acceptable range the computer automatically sends a signal
directly to the tinting machine to adjust the calibration curve. In
the case where the second personal computer is remote from tinting
machine it can be seen that this automatic adjustment process is
also a remote process. The software can also be programmed such
that the adjustments are made when the tinting machine is not in
operation, for example, outside store opening hours. Thus, whilst
the automatic adjustments are automatic in the sense that no
operator input is required, they are not instantaneously made when
the error value is calculated.
[0058] Alternatively, instead of automatic adjustment, the software
can be programmed to alert the user of the second personal computer
26 to the error value, enabling adjustments to be made when
appropriate. The adjustments can still be made remotely under the
control of the operator of the second personal computer 26, but, in
this case, they are not made automatically. It is also possible for
the adjustments to be made locally at the tinting machine 22, by
editing the calibration curve, either by the machine operator or by
a maintenance engineer.
[0059] In addition to determining an error value for each colourant
dispenser, the regression analysis also calculates a confidence
level for each error value. The error values calculated will have a
higher confidence level as the number of dispensed coating
compositions analysed increases. Theoretically, the number of
tinted coating compositions dispensed needs to be in the order of
twenty multiplied by the number of colourants (sixteen in this
example), giving three hundred and twenty. However, it has been
found that error values that equate to actual manually calibrated
data have been generated with less than this theoretical number.
For example, using sixteen colourants, three hundred dispensed
coating compositions has proven to give comparable error
values.
[0060] In both automatic and non-automatic adjustment, the
confidence level corresponding to each colourant dispenser system
error value can be used to decide whether or not adjustments are
required.
[0061] In the case of automatic adjustment, a predetermined
confidence level can be set, above which adjustments are
automatically made, for example, more than ninety percent
confidence might be considered sufficient to permit automatic
adjustment.
[0062] In the case of non-automatic adjustment, the user can
decide, possibly with additional information, if adjustment is
required. For example, the user may suspect a particular colourant
is at fault, and therefore the confidence level might not be so
critical.
[0063] It should be noted that for those colourant dispenser
systems which are used frequently, the confidence level will be
higher. This is important because it is these high use systems
which are more likely to be wear, and therefore more likely to
require adjustment.
[0064] Conversely, if a specific colourant has not been used
frequently, then the error value calculated for that colourant
dispenser system will have been obtained on a small sample of data,
and will therefore have a low level of confidence as to whether the
error value is correct. To address this potential low level of
confidence it is possible to store data for all dispensed coating
compositions containing this low use colourant in conjunction with
colourants whose corresponding colourant dispenser system has not
been adjusted. The stored data can then be added to data generated
for subsequently dispensed coating compositions to create a new
combined data set. It may be that by adding the stored data to the
subsequently generated data, the statistical analysis results in
calculated error values for the low use colourants with
sufficiently high confidence levels. However, if the confidence
level is still too low, it is possible to repeat this process of
combining future data sets with subsets of previous data sets until
a sufficient degree of confidence in the low use colourant error
value is obtained.
[0065] In the case of a colour dispenser system which has not been
used at all, no statistical analysis will be conducted, and
therefore no error value will be generated. This is of even less
concern since the lack of use will result in no wear to the
colourant dispenser system.
[0066] Thus it can be seen that the individual error value
associated with each colourant dispenser system can be determined
by analysing the logged weight data, and then appropriate action
can be taken to adjust individual colourant dispensers, either
automatically or manually, and either locally or remotely.
[0067] A particular benefit of the present invention is where
adjustment of the colourant dispenser system is made automatically
by a processor which is integrated within the tinting machine, with
typically being the processor which runs the tinting machine. In
this case, no remote processing means is required, either to
analyse data, or to activate adjustment.
[0068] It would also be possible to verify the error value
calculated by the regression analysis by running the machine in a
verification mode, where colourant is sequentially dispensed and
weighed before and after dispensing. This could be repeated for
different colourants, and for a different number of times. This
would generate an actual error value which could be compared to the
statistically calculated value. If the actual and calculated values
are comparable, or within a specified range then the adjustment of
the calibration curve can then be made. It will be appreciated that
software controlling the tinting machine can be programmed to
include running the machine in the verification mode, and then
compare the actual results with those calculated using statistical
analysis.
[0069] In another embodiment, the tinting machine can dispense
colourant sequentially, as opposed to the substantially
simultaneous dispensing of the embodiment of FIGS. 1 and 2.
[0070] In such an embodiment it will be appreciated that the
regression statistical analysis described in the embodiment of
FIGS. 1 and 2 can also be employed in the same way to calculate an
error value for each colourant dispenser system, by weighing the
tinted coating composition before adding colourant and after all
colourants have been added. In this case the actual weights are
compared to correct weights which correspond to the total weight of
the tinted coating composition.
[0071] By virtue of the fact that the colourants are dispensed
sequentially, it is also possible to programme the first personal
computer such that the paint container is weighed before dispensing
colourant, and after each individual colourant has been dispensed,
and logging the actual weight of colourant dispensed for each
colourant and for each composition. In this case, regression
analysis is not essential because the sequential nature of the
dispensing enables the difference between actual and correct
weights to be measured directly for individual colourants. The
correct weights in this case are those stored for the individual
colourants in the particular coating composition, and not the total
weight of the coating composition. The statistical analysis in such
a system would then involve, for example, an average of several
readings for that particular colourant dispenser system. It will be
appreciated however that weighing the container after each
colourant has been dispensed will slow down the operation of the
machine.
[0072] In this embodiment, it is possible to weigh the tinted
coating composition both before and after all the colourants have
been dispensed, and after each colourant has been dispensed. In
this way it is possible to calculate two colourant dispenser system
error values for each colourant dispenser system, and more
importantly enable a comparison to be made between the error value
calculated using regression analysis, and the error value
determined from weighing individual colourants. This will enable a
check to be made on calculated error values, but clearly this is
limited to running the machine in sequential dispensing mode.
[0073] Thus, in the case of a tinting machine with sequentially
dispensed colourant, the present invention provides a system that
determines the error value for each colourant dispenser system
using either regression analysis, without any reduction in the
tinting process speed, or alternative statistical analysis on
individually weighed colourant, but with a reduction in the speed
of the tinting process. Clearly, the choice of system will largely
depend on the requirement for the tinting process to be carried out
quickly. For example, in a store where the tinting machine is
infrequently used, the reduction in speed of the process by
weighing individual colourants may not be a concern, however, in a
high use store, the use of regression analysis would seem more
appropriate.
[0074] It will be appreciated that whilst the embodiments described
above are in relation to adjusting the calibration curve for gear
pumps, the invention is equally applicable to other colourant
dispenser systems, for example, bellow machines or piston pumps, or
any system which requires an actuator, for example a stepper motor,
to dispense a given quantity of colourant.
* * * * *