Note: Descriptions are shown in the official language in which they were submitted.
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
IN LINE PRODUCTION OF SOLID OBJECTS
Technical field
o The invention relates to a process for producing solid objects in line.
Background of the invention
Processes for producing solid objects in line are widely used, in particular
in the
~5 consumer goods industry, for products such as tooth-brushes for example. In
general, such solid objects are formed and then printed. In particular,
techniques
of application of substances onto a selected surface area of such solid
objects is
particularly used, mostly for printing onto such solid objects. Existing
printing
techniques are of different kinds. A first kind of printing technique used in
the
2o industry consists in printing a large number of labels which are being
stored onto
large reels, such reels being thereafter fed onto a production line to be
glued
onto the solid objects. A second kind of printing techniques consists in
applying
ink directly onto the outer surface of the solid objects, whereby the print
itself can
be customised so as to indicate for example the date of production or a
particular
25 reference number.
The present invention concerns a process for producing a solid object
comprising
a first step and a second step, the first step consisting in applying a first
substance onto a selected surface area by use of first application means, the
so selected surface area and the solid object being both in motion relative to
the first
application means and the selected surface area being solely in contact with
the
first substance during the first step. Such a process is known from the second
CA 02366598 2001-08-31
WO 00/56609 PCT/CTS00/07138
2
printing technique mentioned above, whereby a custom print is applied directly
onto a solid object, the letters or numbers of the print being typically
formed from
a number of black dots.
s Among the advantages of custom printing information directly onto a solid
object
while in motion relative to the application means is that such information can
be
different for each solid object produced, and that such printing can occur at
high
speed on line. Such a process is particularly useful for example in the
consumer
industry, whereby it is preferable that a solid object is decorated for
example.
~o Typically, such custom printing differs from the other existing process of
the first
kind above, whereby labels are pre-printed independently in a separate process
and stored onto reels, prior to being glued in line onto a solid object.
Indeed, in
such a process using reels of printed labels, all labels will be identical,
and any
label will correspond on the line to any solid object. However, such a process
using reels of printed labels allows use of labels having relatively high
definition
graphics, instead of using a limited number of mono-colour dots to
reconstitute
letters or numbers.
While having these and other advantages, existing processes, and particularly
2o the process of in line custom printing of a matrix of dots or the process
of using
reels of printed labels, have disadvantages. For example, the process of in
line
custom printing of a matrix of dots offers a poor definition suitable for
printing of
simple messages such as a date in one colour but not suitable for printing
high
definition graphics or designs. Further, the process of using reels of printed
2s labels is not flexible as a change of design of the label will require
change of reel,
which involves stopping a production line or requires having a double reel
supporting system allowing to change reel without stopping the line. In any
case,
use of reels of printed labels requires storage of any desired kinds of
labels, as
such labels are not produced directly in line.
It is conventional for solid object for consumer products to carry high
quality printed
images, both in the form of designs for brand marketing, and information for
the
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
3
consumer such as directions for use. Conventionally such images have been
printed onto pressure-sensitive adhesive labels which, after removal of a
protective
backing material for the adhesive, are applied to the solid object. However,
the
handling of such labels for accurate application to solid objects at high
speed
s tends to be difficult, and significant down-time can occur due to backing
paper
breaking or jamming of labels. Furthermore, the labels must be printed
separately
on a printing press, which is expensive and time consuming. The label laminate
and backing paper are also expensive, and add to the waste stream. Also,
factory
space must be set aside and an inventory system established to store the
labels,
~o and to ensure that the correct label is placed on the correct solid object.
A further disadvantage with the use of labels is that if the decoration
artwork
changes, any remaining labels must be thrown away, and new labels printed.
From the time the new artwork is approved, it typically takes 4 to 6 weeks to
make
new printing cylinders or plates, and print and deliver the labels, ready for
~ s application.
As an alternative, images have been printed directly onto solid object by
screen
printing techniques. However, such techniques tend to be slow, particularly
when
multi-coloured images are to be printed, and the quality of image that is
produced
is limited. Typically, only one to four colours are printed at any one time
using
2o screen printing, with the result that the complexity of decoration is
limited. If further
colours are required, this can be achieved by causing the solid object to pass
the
print station a number of times, but this tends to increase costs
dramatically.
Furthermore, when used with non-circular solid object, such as oval solid
object or
solid object having more complex curved shapes, screen printing tends to be
very
2s slow, operating at speeds as low as 50 solid object per minute, and at most
100
solid object per minute.
Furthermore, the screens for use in screen printing tend to take considerable
time
to manufacture. Such screens also need to be replaced frequently, contributing
to
maintenance costs.
so Thermal transfer printing techniques have also been used to form images
directly
onto solid objects. However, such techniques also tend to be slow and, again,
tend to result in poor image quality. In addition, pressure and/or heat
applied to the
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
4
solid object being printed by the transfer mechanism may result in damage to
the
solid object, which is clearly undesirable. Furthermore, the transfer process
requires the use of a transfer film which adds unnecessary waste and cost.
It is well-known that good quality images can be achieved using digital
printing
technology, for instance such as ink jet and laser techniques, and that such
techniques are flexible in terms of their application. Ink jet printing has
typically
been used to print paper or other absorbent materials with water or oil-based
inks.
The invention seeks to provide a process for producing a solid object of the
1o above mentioned kind which can provide both flexibility and high resolution
in the
application of a substance to a solid object, and which can operate in a wide
range of speeds for industrial production.
Summary of the invention
In accordance with the invention, this object is accomplished in a process of
the
above kind in that the second step consists in applying a second substance
onto
the selected surface area by use of second application means after completion
of
the first step, the selected surface area and the hollow body being both in
motion
2o relative to the second application means and the selected surface area
being
solely in contact with the second substance during the second step, the
process
taking place at a continuous line speed.
A process in accordance with the invention has a number of advantages. Since
it
comprises the application of a second substance as well as the first substance
onto the selected surface area while both the solid object and the selected
surface area are in motion relative to the first or second application means,
it
allows to obtain both flexibility as the application can be made directly in
line, and
higher resolution in that more than a single substance is applied onto the
3o selected surface area of the solid object. Due to the improved flexibility,
storage
such as for example storage of high definition labels onto reels, is
significantly
reduced, such lowering production costs. Furthermore, flexibility allows for
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
example to reduce wastage of printed labels which are not used, thus being
beneficial to the environment.
Detailed description of the invention
5
The process of the invention relates to solid object. By solid, it should be
understood that the object is substantially free from empty spaces. Such an
object
may for example be a toothbrush. It should be noted that the selected surface
area
~o my be an integral part of the solid object or may be separate, for example
when it
is onto a label. Indeed, according to the invention, the solid object could be
processed in the following manner: the selected surface area may be onto the
label, the selected surface area situated on the label being treated by the
process
according to the invention prior to being applied onto the solid object.
During
~5 application of the substances on the selected surface area, the solid
object is in
motion also according to the invention, even if the label is not applied onto
the solid
object yet. Indeed, both the solid object and the label are on line, the line
being
such that the label will be applied after printing, for example. The label
could also
be applied blank onto the solid object and the substances may be applied onto
the
2o selected surface area situated on the label as the label is already fixed
to the solid
object. Furthermore, a label may not be use, so that application of the
substance
may take place directly onto the solid object.
Preferred hereby would be solid objects made from a material comprising
thermoplastic resins.
25 The first step of the process according of the invention consists in
applying a first
substance onto a selected surface area. Typically, the substance is an ink,
which is
preferably applied using ink jet technology. The selected surface area
preferably
covers at least 30 cm2. The selected surface area could be placed for example
on
a label, or on the solid object such as a toothbrush. Application is made
using first
3o application means. Typically. Such means comprise an ink jet head of an ink
jet
printer, preferably an ink jet head having a plurality of nozzles.
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
6
According to the invention, the selected surface area and the solid object are
both
in motion relative to the first application means. This does not prevent the
selected
surface area and the solid object to move separately, as a label may be
printed
prior to being applied, for example. However, this means that these two
s components are in motion on the production line. The relative movement could
comprise a component consisting in a movement of the first application means
themselves. Indeed, in particular when printing on a non planar selected
surface
area, it may be preferable to move the application means as well as the
selected
surface area itself. In any case, the solid object is in motion also, so that,
in case of
~ o printing on a label prior to application on the solid object, the solid
object is in
motion on the line towards the point where application of the label will take
place.
Indeed, in a preferred embodiment, the selected surface area is onto the
surface of
a label, the label being fixed onto the solid object after application of the
substances. This differs from another preferred embodiment whereby the
selected
~ s surface area is an integral part of the outer surface of the solid object.
The invention also mentions that the selected surface area is solely in
contact with
the first substance during the first step. This means that there is no
friction between
any elements and the selected surface area. It should be noted that if the
selected
surface area is placed onto a label, the label itself may be in contact with
for
2o example the solid object. Indeed, the selected surface area is meant to be
a two
dimensional surface. Such a friction on the selected surface area would for
example take place in a screen printing application, the speed of which is not
compatible with the process of the invention.
The second step of the invention is similar to the first step and follows the
first step.
25 The process according to the invention is taking place at any current line
speed
depending on the sophistication of the ink jet technology used and the number
of
heads printing identical colours. This is rendered possible by the continuous
movement of the solid object and of the selected surface area and by the
absence
of friction onto the selected surface area. Further more, the plurality of
application
so means allows also to progress with a greater line speed, while obtaining a
satisfactory application. Preferably, the process takes place at a speed of at
least
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
7
metres per minute, even more preferably at least 20 metres per minute and
most preferably at least 28 metres per minute.
In a preferred embodiment, the process further comprises one or more extra
steps,
5 the extra step consisting in applying an extra substance onto the selected
surface
area by use of extra application means after completion of the prior step, the
selected surface area and the solid object being both in motion relative to
the extra
application means and the selected surface area being solely in contact with
the
extra substance during the extra step. It should be noted that it is preferred
that a
~o different substance is applied for each of these extra steps. A most
preferred
embodiment comprises four extra steps, each of the six substances being a
different ink, so that high resolution images may be achieved, as well as high
resolution grey scale images with a high contrast.
In a preferred embodiment of the present invention, a process for printing an
image
onto a selected surface area such as on non-planar solid object surfaces for
example, comprises moving a line of solid objects in a continuous manner past
an
ink jet head having an array of nozzles spaced apart in a direction transverse
to the
direction of movement of the line of solid objects and through which ink is
ejected,
2o and moving each solid objects and/or the ink jet head relative to one
another as
the said solid object passes the ink jet head, so that during printing the
distance
between the ink jet head and the solid object surface to be printed remains
substantially constant and so that each portion of the said surface passes the
ink
jet head only once.
2s According to another preferred embodiment of the present invention, an
apparatus
for printing an image onto solid object surfaces comprises a receptacle for
each
solid object, conveyor means for moving the receptacles in a continuous manner
past an ink jet head having an array of nozzles transverse to the direction of
movement of the receptacles and through which ink is ejected, and means for
3o moving each solid object and/or the ink jet head relative to one another as
the said
solid object passes the ink jet head, so as to maintain during printing a
constant
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
8
distance between the solid object surface to be printed and the ink jet head
and so
that each portion of the said surface passes the ink jet head only once.
The process and apparatus of the preferred embodiments of the invention are
capable of printing, or decorating, non-planar solid object at speeds suitable
for
commercial production. For instance, in the preferred embodiments of the
invention, the process is capable of printing at least 150 solid objects per
minute,
preferably more than 200 solid objects per minute, and more preferably up to
500
solid objects per minute, while achieving high image quality and avoiding
damage
to the solid objects.
o Another advantage of the present invention is that it is readily adaptable
for use
with different shapes and/or sizes of solid objects or labels, foq example,
and
different artwork and/or text.
Yet another advantage of the present invention is that it is capable of
decorating
solid objects at reduced cost compared to prior art processes, by for example
s eliminating the need for labels and backing papers, transfer films, or
printing plates
that are expensive to design and maintain.
It should be noted that for example, a solid object having a non-planar
surface and
having an image printed on that surface is obtainable by a process or by use
of
apparatus as described above.
2o In the preferred process of the present invention, a line of solid objects
is moved
continuously past an ink jet head. In the context of this Application, by a
line of
solid objects it is intended to cover a row of solid objects, or any other
arrangement
whereby a number of solid objects passes an ink jet head in sequence. The
solid
objects may be positioned vertically or horizontally during printing,' but
preferably
2s they are positioned vertically.
Furthermore, when the line of solid objects is described as moving
continuously it
is intended to mean that between printing one solid object and the next solid
object
in the line, the line of solid objects does not stop moving, unless, for
example, a
change in the process needs to be made, or maintenance of the printing
apparatus
3o is required.
During printing it is essential to maintain a small and substantially constant
distance between the surface of the solid object to be printed and the ink jet
head.
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
9
Otherwise, the position and size of the ink dots produced on the surface of
the
solid object will vary according to which portion of the surface is being
printed,
which may in some places lead to smudging of the image, and in others a very
faint image, or result in damage to the ink jet head or solid object.
s Generally, prior to printing, the distance between the surface to be printed
and the
ink jet head will be set at a pre-determined value. Typically, the pre-
determined
distance will be maintained in the range 0.2 to 4 mm, preferably 0.5 to 2.5
mm, as
with larger distances air currents may interfere with the ink jet, leading to
poor
image quality. This is what is meant by a substantially constant distance in
the
~o context of this Application. More preferably, the distance is maintained as
constant
at 1 mm " 0.5mm.
The pre-determined distance is maintained by moving the solid object to be
printed
and/or the ink jet head. For instance, the ink jet head may be made to move to
follow the profile of the solid object to be printed. However, it is
preferred, for
~s simplicity, that the ink jet head remain stationary, and that each solid
object is
caused to move relative thereto. In this case, it is preferred that, prior to
printing,
each solid object is arranged so that the leading portion, or edge, of the
solid object
surface to be printed, in the direction of movement of the line of solid
objects, is at
the pre-determined distance from the ink jet head. The solid object is then,
2o gradually, rotated about its longitudinal axis to bring each portion of the
solid object
surface in tum to the pre-determined set distance from the ink jet head as the
surface moves past that head, until the trailing portion, or edge, of the
solid object
surface is at the pre-determined distance from the ink jet head. Forseeably,
when
solid objects having complex shapes are to be printed it may be necessary to
2s reverse the direction of rotation of the solid object as it passes the ink
jet head.
However, it is preferred for the speed of the overall process that when
rotating
each solid object each portion of its surface that is to be printed passes the
ink jet
head only once.
The direction and angle of rotation first applied will depend upon the shape
of the
3o solid object to be printed, and the shape of any curved path it is made to
follow.
For instance, if the solid object is made to move in a substantially straight
line and
has a surface which is convex to the ink jet head, the leading portion of that
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
surface must first be moved towards the ink jet head, and then gradually away
from
the ink jet head until the ink jet head reaches the apex, or turning point, of
the
curved surface, and then the trailing edge of the surface must be moved
gradually
towards the ink jet head.
5 If the solid object is made to move in a curved path, the solid object may
have to
rotate either towards or away from the ink jet head, depending upon the
respective
radii of curvature of the curved path and the solid object surface. Typically,
the
radius of the curvature of the solid object will be less than that of the
curved path,
and this requires movement as described above. However, if the radius of
1o curvature of the solid object is greater than that of the curved path, the
leading
edge of the solid object may first have to be moved gradually away from the
ink jet
head until the head reaches the apex of the curved surface, and then the
trailing
edge moved so that this gradually approaches the head.
During printing, the frequency at which ink drops are ejected from the ink jet
head
1s may need to be adjusted to compensate for the slight variation in linear
velocity of
the solid object surface as it passes the ink jet head. The ink jet ejection
timing
may also need to be adjusted to compensate for the fact that for the most part
during printing the ink jet head is not normal to the solid object surface.
Such
modifications, however, are well within the expertise of the skilled man.
2o Movement of the solid object relative to the ink jet head in the required
manner
may be achieved in a number of ways. For instance, a simple servo motor can be
used, or a cam mechanism. If a motor is used it will, typically, be controlled
by a
computer program specific to the size and shape of the solid object being
printed,
so that a simple change of program will adapt the process for printing a
different
2s solid object. This may, therefore, prove more convenient than using a cam
mechanism.
If required, the present invention may utilise at least one sensor to monitor
the
distance between the solid object surface and the ink jet head. Any suitable
sensor can be used, for instance an infra-red sensor, a laser sensor, a sonic
so proximity sensor. The sensor is in communication with the means for moving
the
ink jet head and/or solid object relative to one another, allowing adjustment
of that
CA 02366598 2001-08-31
WO 00/56609 PCT/LJS00/07138
11
moving means if necessary during a print cycle, or after changing over from
printing one type of solid object to another, of a different size and/or
shape.
It is preferred that during printing each solid object is held within a
receptacle on a
conveyor or a carrousel. In this case, movement of each solid object relative
to the
s ink jet head may be achieved by moving its respective receptacle. Each
receptacle
preferably comprises means for holding its solid object so there is
substantially no
relative motion between the solid object and its receptacle during the
printing
operation. Typically, the holding means contacts the solid object at at least
one
position at its top and its base. Any suitable holding means can be used, one
1o example is to employ a tapered stopper, for insertion into the top of the
solid object
to a snug fit, and to hold the base of the solid object in a tapered
receptacle having
substantially the same profile as the base of the solid object. Preferably,
the
nature of the holding means allows the receptacle to be used with solid
objects of
different sizes and/or shapes, and to be readily adaptable thereto, thereby
allowing
1 ~ conversion from one product line to another, with minimal delay, which
represents
a significant advantage in present day commercial production.
The process of the invention may use one or a number of ink jet heads,
depending
upon the complexity of the image to be printed and/or the number of surfaces
of
the solid object to be printed. Each ink jet head comprises an array of
nozzles that
2o are spaced apart in a direction transverse to the direction of movement of
the line,
or row, of solid objects to be printed. Ink may be ejected from the nozzles in
a
continuous manner or on a drop-on-demand basis, under digital control, as is
well
described in the literature. Preferably ink is ejected from the nozzles on a
drop-on-
demand basis.
25 The number of nozzles and the width of the array are selected according to
the
image to be printed, as the solid object surface will only make a single pass
past
each ink jet head. Typically, each ink jet head will have at least 7 nozzles
per mm,
preferably at least 12 nozzles per mm, which may be arranged in one or more
parallel lines. Most preferably, the ink jet head will be capable of printing
at least
30 200 drops of ink per inch in the direction of the solid object movement,
and
preferably 360 drops per inch.
CA 02366598 2001-08-31
WO 00/56609 PCT/LTS00/07138
12
It may also be preferred to utilize multiple grey scale levels, to achieve
high quality
images and small text quality. Preferably at least four grey scale levels will
be
used. An example of an ink jet head capable of achieving this is the Xaarjet
1000,
supplied by Xaar.
When a number of ink jet heads are used to print differently-coloured inks,
and by
this we also mean black and white inks, it is essential that these be arranged
to
achieve good colour-to-colour registration on the final printed solid object.
Typically, the accuracy of registration that is required is such that the
error in
positioning of differently-coloured dots is 100-400 :m, preferably less than
200 :m,
1o and more preferably less than or equal to 70 :m.
To obtain, in combination, solid block colours, good text, and good
photographic
images, the process of the invention may be combined with special colour
printing
techniques. For instance, to achieve maximum flexibility and high quality
printing, it
is preferred to use so called "Hi-Fi" colour printing using 6 to 7 colours.
This may
utilize for example cyan, magenta, yellow ~ and black, plus either i) green
and
orange or ii) red, green and blue. This expands the colour space available and
enables higher quality decoration at relatively low cost, and avoids the need
for
numerous special colours in order to produce solid colours, as is typical in
printing
artwork for solid objects.
2o When it is desired to print more than one portion of a solid object
surface, for
instance diametrically-opposed surface portions or opposite sides of a solid
object,
after each solid object has passed a first ink jet head it is rotated about
its
longitudinal axis, for example through at least 90°, to present the
next surface
portion or side of the solid object to be printed to another ink jet head. For
2s instance, if opposite sides of a solid object are to be printed, each solid
object will
simply be rotated through approximately 180° between the ink jet heads
or sets of
ink jet heads. Then, when printing the second surface portion or side, the
solid
object and/or the ink jet head is again caused to move in the manner described
above, in order to maintain a substantially constant distance between the
solid
30 object surface and the ink jet head.
Any suitable ink may be used for printing, although certain inks may be
preferred
depending upon the material from which the solid object to be printed is made.
For
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
13
instance, for non-absorbent solid objects, eg. plastic, metal and glass solid
objects,
it may be preferred to use a phase-change ink, such as a hot-melt ink, a heat-
fusable non-solvent toner ink, or a radiation-curable ink, typically a UV-
curable ink.
In this case, a means for fusing or curing the ink is preferably provided,
either after
s each ink jet head, if there are a number of these, and/or at the end of the
overall
printing process. Irrespective of the type of ink used, the solid object
surface
should have sufficiently low surface energy to enable ink adhesion. This can
be
accomplished, for example, by flame treatment of plastic solid objects, as is
well
known in the art.
1o The radiation curable inks may be preferred over those that require drying
by
heating, as their use is less likely to result in damage to the solid object.
UV-
curable inks are particularly preferred, as these adhere readily to plastic
surfaces
and are durable. The use of such inks in ink jet technology is described in
the art.
The present invention is suitable for printing a wide variety of sizes and/or
shapes
15 Of solid objects, but is particularly suited to printing solid objects
having curved or
non-planar surfaces. It is particularly suitable for printing solid objects
having
surfaces which curve in one sense or direction only, for instance surfaces
which
are either convex or concave, as opposed to surfaces containing both convex
and
concave portions. Examples include toothbrushes.
2o The present invention is also suitable for printing solid objects of a wide
variety of
materials, for instance paper-board, cardboard, plastic, glass, and metal. Its
principle purpose, however, is for printing relatively lightweight plastic
solid objects,
typically of polyethylene polypropylene, nylon, polyester, or
polyvinylalcohol, for
use in the detergent, beauty-care, cosmetics, paper and food industries, as
well as
2s labels, for example. As products in these industries often require updating
on a
regular basis, and quickly in response to market change or competitor
activity, it is
essential that solid objects be printed quickly, and that the printing process
can be
adapted readily to different product lines. The present invention satisfies
both
these requirements for the first time, and at high speeds similar to filling-
line
3o speeds.
Reference is now made to the accompanying drawings:
CA 02366598 2001-08-31
WO 00/56609 PCT/US00/07138
14
Figure 1 is a plan view from above of printing apparatus according to the
present
invention; and
Figure 2 is an enlarged orthogonal view of one station of Figure 1, equipped
with
one embodiment of the solid object receptacle moving means.
s Referring to Figure 1, apparatus 1 comprises a rotating carrousel 2 which
carries a
number of receptacles 3 which carry solid objects 4 past a series of ink jet
heads 5.
Each receptacle comprises holding means (not shown) for its respective solid
object.
Each of the receptacles is movable on the carrousel so as to maintain a small
and
o substantially constant distance between the surface of the solid object to
be printed
and the respective ink jet head. A UV lamp 6 is provided after each fink jet
head, in
order to cure the ink printed onto the solid object, and a further UV lamp 7
is
provided, if needed, after the final ink jet head, to ensure complete curing
of the
printed inks. As an alternative to UV lamps, optical fibres may be employed to
~ s convey UV light from a more distant source, thereby conserving space.
The individual solid objects 4 are deposited in their respective receptacles 3
by a
conveyor 8 leading from a sorter 9 of conventional type. While on conveyor 8,
the
solid objects may be subject to other treatments, for instance by a flame
treater 10,
which acts to reduce surface tension and promote ink adhesion. In addition, a
20 180°-rotation station 11 is provided, to present the other side of
the solid object,
which has already been printed, to the subsequent ink jet heads.
After printing, the solid objects leave the carrousel and are subject to
inspection as
to print quality using video equipment 12.
With reference to Figure 2, a solid object 21 is held in a tapered puck 22,
with a
25 tapered plug 23, suspended from a frame 24, inserted into the top of the
solid
object. The puck is supported on a carousel 25 (only a portion of which is
shown)
which causes the solid object to pass ink jet head 26. Underneath the
carousel,
motor 27 rotates shaft 28 which is attached to the puck, thereby rotating the
solid
object in front of the ink jet head. The motor is programmable to cause
rotation of
3o the solid object so that the distance between the solid object surface to
be printed
and the ink jet head is maintained, typically, below 2 mm.
