U.S. patent application number 11/962919 was filed with the patent office on 2008-05-01 for apparatus and methods for sensing and clamping discs.
This patent application is currently assigned to Rimage Corporation. Invention is credited to John S. Lee, Douglas J. Lenz, Westin W. Nelson, Phillip C. Salisbury.
Application Number | 20080100657 11/962919 |
Document ID | / |
Family ID | 34838107 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080100657 |
Kind Code |
A1 |
Salisbury; Phillip C. ; et
al. |
May 1, 2008 |
APPARATUS AND METHODS FOR SENSING AND CLAMPING DISCS
Abstract
Apparatus and methods are provided. At least one clamping finger
of a movable tray of a compact disc printer pushes against an outer
periphery of a compact disc disposed on a surface of the tray to
clamp the compact disc between the clamping finger and a pair of
studs that protrude from the surface of the tray and engage a
periphery of a hole passing through a center of the compact disc. A
carriage of the printer for moving an ink jet cartridge attached
thereto across the compact disc to deposit an image on the compact
disc may include a sensor. The sensor can be used to determine the
presence of a compact disc on the tray, whether the compact disc is
clamped to the tray, and a dimension of the compact disc, and to
perform a calibration method.
Inventors: |
Salisbury; Phillip C.;
(Golden Valley, MN) ; Lenz; Douglas J.; (Prior
Lake, MN) ; Lee; John S.; (Coon Rapids, MN) ;
Nelson; Westin W.; (Dayton, MN) |
Correspondence
Address: |
Leffert Jay & Polglaze, P.A.
P. O. Box 581009
Minneapolis
MN
55458-1009
US
|
Assignee: |
Rimage Corporation
|
Family ID: |
34838107 |
Appl. No.: |
11/962919 |
Filed: |
December 21, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10778005 |
Feb 12, 2004 |
7311367 |
|
|
11962919 |
Dec 21, 2007 |
|
|
|
Current U.S.
Class: |
347/14 ; 347/104;
G9B/17.003 |
Current CPC
Class: |
B41J 3/4071 20130101;
G11B 23/40 20130101 |
Class at
Publication: |
347/014 ;
347/104 |
International
Class: |
B41J 2/01 20060101
B41J002/01; B41J 29/38 20060101 B41J029/38 |
Claims
1. A method of clamping a compact disc to a printer, comprising:
positioning the compact disc on a surface of a movable tray of the
printer so that a pair of studs protruding from the surface of the
tray extend into a hole passing through a center of the compact
disc; and moving at least one clamping finger into engagement with
an outer periphery of the compact disc so as to push a periphery of
the hole passing through the center of the compact disc against the
pair of studs.
2. The method of claim 1, wherein moving at least one clamping
finger is in response to moving the tray into the printer.
3. The method of claim 1, wherein moving at least one clamping
finger further comprises: moving the tray into the printer; as the
tray is moving, engaging a lug protruding from a stationary surface
of the printer with an actuator arm connected to a first shaft
rotatably attached to the tray as the tray moves past the lug,
wherein the lug rotates the first shaft; and imparting the rotation
of the first shaft to a second shaft via a link movably connected
between the first shaft and the second shaft, wherein the second
shaft is rotatably attached to the tray and wherein the second
shaft is connected to the at least one clamping finger so that the
rotation of the second shaft rotates the at least one clamping
finger.
4. The method of claim 1, and further comprising biasing the at
least one finger against the outer periphery of the compact disc
during clamping.
5. A method of clamping a compact disc to a printer, comprising:
positioning the compact disc on a surface of a movable tray of the
printer so that a pair of studs protruding from the surface of the
tray extend into a hole passing through a center of the compact
disc; moving at least one clamping finger into engagement with an
outer periphery of the compact disc so as to push a periphery of
the hole passing through the center of the compact disc against the
pair of studs; and verifying clamping of the compact disc.
6. The method of claim 5, wherein verifying clamping of the compact
disc comprises reflecting a beam of light off a surface of the at
least one clamping finger.
7. A method of operating a compact disc printer, comprising:
emitting a beam of light onto a predetermined point on a movable
tray of the printer from a sensor disposed on a carriage of the
printer; indicating that the compact disc is clamped to the tray
when a surface of a clamping finger coincides with the point and
reflects the light back to the sensor, wherein when the clamping
finger coincides with the point, the clamping finger is in
engagement with an outer periphery of the compact disc; and
indicating a clamping error when the surface of a clamping finger
does not coincide with the point and the light is not reflected
back to the sensor, wherein when the clamping finger does not
coincide with the point, the clamping finger is not in engagement
with the outer periphery of the compact disc.
8. The method of claim 7, and further comprising moving the tray
and the carriage to align the sensor with the point.
9. The method of claim 7, wherein when the surface of a clamping
finger does not coincide with the point, the beam of light is
emitted into a slot of the tray.
10. A method of operating a compact disc printer, comprising:
aligning a sensor with a predetermined first point on a movable
tray of the printer, wherein the predetermined first point is at a
known first distance from a predetermined second point
corresponding to a center of a compact disc when the compact disc
is disposed on the tray and wherein the first and second points
coincide with a slot in the tray that is substantially parallel to
a direction of motion of the tray, the sensor disposed on a
carriage of the printer for moving an ink jet cartridge attached
thereto across the compact disc to deposit an image on the compact
disc; emitting a beam of light from the sensor into the slot at the
first point; moving the tray so that the beam of light moves within
the slot toward the second point; indicating that no compact disc
is present when the beam of light arrives at the second point
without being reflected; when a compact disc is located on the
tray, reflecting the beam of light back to the sensor from the
compact disc when the beam of light encounters an outer periphery
of the compact disc; and computing a dimension of the compact disc
by subtracting a distance traveled by the tray between the first
point and the outer periphery of the compact disc from the first
distance.
11. The method of claim 10, and further comprising determining a
type of the compact disc from a look-up table based on the
dimension of the compact disc.
12. The method of claim 10, and further comprising determining the
distance traveled by the tray by counting a number of rotations of
a stepper motor that moves the tray.
13. A method of clamping a compact disc to a printer, comprising:
positioning the compact disc on a surface of a movable tray of the
printer so that a pair of studs protruding from the surface of the
tray extend into a hole passing through a center of the compact
disc; disposing an adaptor between an outer periphery of the
compact disc and at least one clamping finger movably attached to
the tray; and moving the at least one clamping finger into
engagement with the adaptor so as to push the adaptor into
engagement with the periphery so as to push a periphery of the hole
passing through the center of the compact disc against the pair of
studs.
14. The method of claim 13, and further comprising verifying
clamping of the compact disc.
15. The method of claim 14, wherein verifying clamping of the
compact disc comprises reflecting a beam of light off a surface of
the at least one clamping finger.
16. The method of claim 13, wherein moving at least one clamping
finger is in response to moving the tray into the printer.
17. The method of claim 13, wherein moving at least one clamping
finger further comprises: moving the tray into the printer; as the
tray is moving, engaging a lug protruding from a stationary surface
of the printer with an actuator arm connected to a first shaft
rotatably attached to the tray as the tray moves past the lug,
wherein the lug rotates the first shaft; and imparting the rotation
of the first shaft to a second shaft via a link movably connected
between the first shaft and the second shaft, wherein the second
shaft is rotatably attached to the tray and wherein the second
shaft is connected to the at least one clamping finger so that the
rotation of the second shaft rotates the at least one clamping
finger.
18. The method of claim 13, and further comprising biasing the at
least one finger against the adaptor during clamping.
Description
[0001] This application is a Divisional of U.S. application Ser.
No. 10/778,005, titled "APPARATUS AND METHODS FOR SENSING AND
CLAMPING DISCS," filed Feb. 12, 2004, (Allowed) which is commonly
assigned and incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates generally to compact disc
printers and in particular the present invention relates to sensing
and clamping discs.
BACKGROUND OF THE INVENTION
[0003] Compact disc publishing and replicating systems often use an
ink jet printer to print a label directly on a compact disc (CD).
This involves placing the disc on a movable tray and moving an ink
jet cartridge over the disc to deposit ink droplets onto the disc
as the tray moves the disc substantially perpendicular to the
motion of the cartridge. One problem that can occur during printing
is disc movement, which can cause blurred images, images printed
atop other images, etc. Therefore, it is common to clamp the disc
to the tray. However, many clamping mechanisms do not repeatedly
clamp the discs in the same location on the tray. That is, the
centers of successively clamped compact discs do not always
coincide with substantially the same predetermined point on the
tray that is used as a reference during printing. This may make it
difficult to print an image in the same location on these discs.
Moreover, many disc printers are not capable of verifying that a
disc is correctly clamped on the tray.
[0004] It is often desirable to print on different size discs. One
problem is identifying the disc size so that the printer deposits a
correctly sized image on the disc. For example, the printer may be
set for printing a large image on a small disc, which may cause ink
to be deposited outside the boundaries of the disc, such as on the
tray.
[0005] For the reasons stated above, and for other reasons stated
below which will become apparent to those skilled in the art upon
reading and understanding the present specification, there is a
need in the art for alternatives to existing compact disc
printers.
SUMMARY
[0006] The above-mentioned problems with compact disc printers and
other problems are addressed by the present invention and will be
understood by reading and studying the following specification.
[0007] One embodiment of the invention provides a compact disc
printer having a movable tray to hold a compact disc for printing
upon by the printer. At least one clamping finger is movably
attached to the tray and is adapted to selectively engage an outer
periphery of the compact disc. A pair of studs protrude from a
surface of the tray for engaging a periphery of a hole passing
through a center of the compact disc when the at least one clamping
finger engages the outer periphery of the compact disc to clamp the
compact disc between the at least one clamping finger and the pair
of studs.
[0008] Another embodiment of the invention provides a method of
clamping a compact disc to a printer that includes positioning the
compact disc on a surface of a movable tray of the printer so that
a pair of studs protruding from the surface of the tray extend into
a hole passing through a center of the compact disc; and moving at
least one clamping finger into engagement with an outer periphery
of the compact disc so as to push the a periphery of a hole passing
through a center of the compact disc against the pair of studs.
[0009] Another embodiment provides a method of operating a compact
disc printer that includes emitting a beam of light onto a
predetermined point on a movable tray of the printer from a sensor
disposed on a carriage of the printer. The method includes
indicating that the compact disc is clamped to the tray when a
surface of a clamping finger coincides with the point and reflects
the light back to the sensor, wherein when the clamping finger
coincides with the point, the clamping finger is in engagement with
an outer periphery of the compact disc. The method further includes
indicating a clamping error when the surface of a clamping finger
does not coincide with the point and the light is not reflected
back to the sensor, wherein when the clamping finger does not
coincide with the point, the clamping finger is not in engagement
with the outer periphery of the compact disc.
[0010] Another embodiment provides a method of operating a compact
disc printer that includes aligning a sensor with a predetermined
first point on a movable tray of the printer. The predetermined
first point is at a known first distance from a predetermined
second point corresponding to a center of a compact disc when the
compact disc is disposed on the tray. The first and second points
coincide with a slot in the tray that is substantially parallel to
a direction of motion of the tray. The sensor is disposed on a
carriage of the printer. Emitting a beam of light from the sensor
into the slot at the first point and moving the tray so that the
beam of light moves within the slot toward the second point are
included in the method. The method includes indicating that no
compact disc is present when the beam of light arrives at the
second point without being reflected. The method includes, when a
compact disc is located on the tray, reflecting the beam of light
back to the sensor from the compact disc when the beam of light
encounters an outer periphery of the compact disc. Computing a
dimension of the compact disc by subtracting a distance traveled by
the tray between the first point and the outer periphery of the
compact disc from the first distance is included in the method.
[0011] Further embodiments of the invention include methods and
apparatus of varying scope.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 illustrates an ink jet compact disc printer according
to an embodiment of the present invention.
[0013] FIG. 2A is a top detailed view of a tray of a compact disc
printer illustrating clamping of a circular compact disc to the
tray according to another embodiment of the present invention.
[0014] FIG. 2B is a top detailed view of a tray of a compact disc
printer illustrating clamping of a rectangular compact disc to the
tray according to another embodiment of the present invention.
[0015] FIG. 3 is a side view of a portion of a compact printer
according to another embodiment of the present invention.
[0016] FIG. 4 is a bottom view of a portion of tray of a compact
disc printer according to another embodiment of the present
invention.
[0017] FIG. 5 is an exploded view of a clamping assembly of a
compact disc printer according to another embodiment of the present
invention.
[0018] FIG. 6 is an enlarged detailed view of a region 600 of FIG.
1 according to another embodiment of the present invention.
[0019] FIG. 7 is a top view of a compact disc clamped to a tray of
a compact disc printer for illustrating a method performed by the
printer according to another embodiment of the present
invention.
[0020] FIG. 8 illustrates a clamping error.
[0021] FIG. 9 illustrates clamping of a compact disc according to
another embodiment of the present invention.
DETAILED DESCRIPTION
[0022] In the following detailed description of the invention,
reference is made to the accompanying drawings that form a part
hereof, and in which is shown, by way of illustration, specific
embodiments in which the invention may be practiced. In the
drawings, like numerals describe substantially similar components
throughout the several views. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the invention. Other embodiments may be utilized and structural,
logical, and electrical changes may be made without departing from
the scope of the present invention. The following detailed
description is, therefore, not to be taken in a limiting sense, and
the scope of the present invention is defined only by the appended
claims and equivalents thereof.
[0023] FIG. 1 illustrates an ink jet compact disc printer 100
according to an embodiment of the present invention. A movable tray
102 of printer 100 carries a compact disc 104, such as but not
limited to a CD, a CD-R, a DVD-R, etc., into and out of a housing
106 of printer 102 along an axis 108 that bisects compact disc 104.
Compact disc 104 can be circular as shown and can have different
diameters, such as 120 mm, 80 mm, etc. Alternatively, compact disc
104 can be square, rectangular, triangular, etc. Printer 100 has a
print carriage 110 movably disposed on a rail 112 having a central
axis 118 that is substantially perpendicular to axis 108, as shown
by the cut-away of FIG. 1. An ink jet print cartridge 114 is
removably attached to print carriage 110. During printing, print
carriage 110 rides on rail 112 for conveying ink jet cartridge 114
across compact disc 104 to deposit ink onto compact disc 104 as
tray 102 moves substantially perpendicular to the direction of
motion of print carriage 110. For various embodiments, printer 100
is connectable to a computer 160.
[0024] FIG. 2A is a top detailed view of tray 102 illustrating
clamping of compact disc 104 to tray 102, according to another
embodiment of the present invention. To clamp compact disc 104 to
tray 102, clamping fingers 210 are moved against an outer periphery
212 of compact disc 104 to urge a periphery 214 of a coaxial hole
216 passing though the center of compact disc 104 against
stationary studs 218 and 219 protruding from a surface 217 of the
tray. For one embodiment, fingers 210 are positioned to push
compact disc 104, and thus periphery 214 of hole 216, against studs
218 and 219. Clamping compact discs in this fashion acts to ensure
that successively clamped compact discs are positioned at
substantially the same location on tray 102. That is, the centers
of successively clamped compact discs coincide with substantially
the same predetermined point on the tray 102.
[0025] For one embodiment, fingers 210 are mounted on a common
shaft 220 that rotates fingers 210 against compact disc 104. For
one embodiment, fingers 210 are integral with shaft 220. The
present invention is not limited to two fingers, however. Rather, a
single finger 210 may be used that is moved against compact disc
104, such as by rotation of a shaft that mounts the finger. As
described below, at least one of fingers 210 has an extension (or
sensing surface) 211 that is detectable by a sensor on carriage
110. The force exerted by one, two, or more clamping fingers 210
can be directed along a radius passing through a center 224 of
compact disc 104, or the force can be directed at an angle to the
radius, as long as there is a net force directed along a
perpendicular bisector of a straight line 221 interconnecting studs
218 and 219.
[0026] Studs 218 and 219 are an angle .theta. apart, as measured
around the periphery 214, and can be located on either side of the
axis 108, as shown in FIG. 2A, or can be located on the same side
of axis 108. Studs 218 and 219 can be symmetrically or
asymmetrically disposed about axis 108. For another embodiment, the
angle .theta. is about 90 degrees, but can range from about 30
degrees to about 150 degrees.
[0027] For another embodiment, clamping fingers 210 are moved
against outer periphery 212 of compact disc 104 to urge, e.g.,
push, another portion of periphery 212 against stationary studs 290
and 291 protruding from surface 217 of the tray, as shown in FIG.
2A, instead of urging periphery 214 of hole 216 against studs 218
and 219. Studs 290 and 291 are an angle .phi. apart, as measured
around the periphery 212, and can be located on either side of the
axis 108, as shown in FIG. 2A, or can be located on the same side
of axis 108. Studs 290 and 291 can be symmetrically or
asymmetrically disposed about axis 108. The angle .phi. can range
from about 30 degrees to about 150 degrees. For another embodiment,
studs 290 and 291 are located on an opposite side of an axis 298
from clamping fingers 210, where axis 298 is substantially
perpendicular to axis 108, bisects compact disc 104, and passes
through center 224 of compact disc 104.
[0028] FIG. 2B illustrates clamping of compact disc 104 when it has
a rectangular shape according to another embodiment of the present
invention. Elements common to FIGS. 2A and 2B are commonly numbered
and are as described above. To clamp compact discs of different
sizes and shapes, e.g., different from the size of the compact disc
shown in FIG. 2A, an adaptor is 240 is disposed between clamping
fingers 210 and the periphery 212 of the compact disc, as shown in
FIG. 2B. For various embodiments, the adaptor is sized for
different values of a dimension r of the compact disc, where r is
the distance along axis 108, i.e., along the direction of travel of
tray 102, between center 224 of compact disc 104 and periphery 212.
Note that for circular compact discs the dimension r is the radius
of the disc, whereas, for a square or a rectangular compact disc,
the dimension r is half a side length of the square or rectangle.
Clamping fingers 210, for one embodiment, push adaptor 240 against
compact disc 104 so as to push periphery 214 of hole 216 against
studs 218 and 219. For some embodiments, an aperture 225 is cut
into tray 102, e.g., adjacent an end of tray 102 distally of the
printer when the tray is extended, as shown in FIGS. 2A and 2B. In
one embodiment, aperture 225 serves as a reference location on tray
102.
[0029] For another embodiment, clamping fingers 210 are or adaptor
240 is moved against outer periphery 212 of compact disc 104 to
urge, e.g., push, another portion of periphery 212 against
stationary studs 293 and 294 protruding from surface 217 of the
tray, as shown in FIG. 2B, instead of urging periphery 214 of hole
216 against studs 218 and 219. Studs 293 and 294 can be located on
either side of the axis 108, as shown in FIG. 2B, or can be located
on the same side of axis 108. Studs 293 and 294 can be
symmetrically or asymmetrically disposed about axis 108. For
another embodiment, studs 293 and 294 are located on an opposite
side of axis 298 from clamping fingers 210.
[0030] Tray 102 and the clamping features described above are not
limited to compact disc printers with ink-jet cartridges and can be
used with compact disc printers employing thermal transfer heads in
conjunction with print ribbons or the like.
[0031] FIG. 3 is a side view of a portion of printer 100. FIG. 3
shows that print carriage 110 has a sensor 310 for detecting the
presence of a surface of an object and thereby an edge of the
object, such as compact disc 104. Sensor 310 has an emitter 312 and
a receiver 314. In operation, emitter 312 emits a beam of light
316. When beam of light 316 encounters a surface capable of
reflecting the light, such as a surface of compact disc 104, the
surface reflects the light, and receiver 314 captures the reflected
light 318. Upon capturing the reflected light, sensor 310 sends a
signal to a controller 320 of printer 100 indicating the presence
of a surface. It should be noted that when the beam of light is
emitted onto a non-reflective surface or into a slot, no light is
reflected, the receiver does not detect any reflected light, and
sensor 310 does not detect the presence of a surface.
[0032] FIG. 4 is a bottom view of a portion of tray 102
illustrating a clamping assembly 400 according to another
embodiment of the present invention. FIG. 5 is an exploded view of
the clamping assembly 400. Clamping assembly 400 includes the shaft
220 connected to the clamping fingers 210, as discussed above in
conjunction with FIG. 2A. A moment arm 430 is connected to shaft
220. One or more springs 432, such as a torsion springs, are
connected to shaft 220 by moment arm 430. Spring 432 is also
connected to tray 102 by an end 434 of spring 432, as shown in FIG.
4. Spring 432 biases clamping fingers 210 against periphery 212 of
compact disc 104. A link 440 movably connects shaft 220 to an
actuating arm 446 that is connected to a shaft 442, as shown in
FIGS. 4 and 5. That is, link 440 is movably connected to shaft 220
and shaft 442. Specifically, for one embodiment, link 440 is
rotatably connected to a moment arm 435 that is connected to shaft
220, and link 440 is rotatably connected to a moment arm 446. Shaft
220 and shaft 442 are rotatably attached to tray 102. Actuating
arms 444 and 445 are also connected to shaft 442, as shown in FIGS.
4 and 5. For one embodiment, actuating arms 444 and 445 and moment
arm 446 are integral with shaft 442. As discussed below, actuating
arms 444 and 445 respectively turn shaft 442 in opposite directions
upon engaging stationary lugs attached to the printer 100.
[0033] FIG. 6 is an enlarged detailed view of region 600 of FIG. 1
according to another embodiment of the present invention. As tray
102 moves into and out of printer 100, it moves over region 600 and
lugs 610 and 620 protruding from a stationary surface 605 of
housing 106 of printer 100. For one embodiment, region 600
corresponds to a portion of a tray guide that is secured to housing
106.
[0034] As tray 102 moves into printer 100, actuating arm 445 of
clamping assembly 400 engages an inclined surface 612 of lug 610,
which exerts a force on actuating arm 445 that rotates shaft 442
relative to tray 102. Rotation of shaft 442 moves link 440
substantially parallel to tray 102 in a direction opposite the
motion of tray 102. Link 440 then rotates shaft 220 in a first
rotational direction to rotate clamping fingers 210, within slots
280 (shown in FIGS. 2A and 2B) disposed in tray 102, into contact
with compact disc 104, as shown in FIGS. 2A and 2B. Rotation of
shaft 220 in the first rotational direction moves spring 432 past a
toggle point, shifting a net spring force to bias clamping fingers
210 against compact disc 104 or against adaptor 240. This net
spring force provides the clamping force for clamping compact disc
104 to tray 102. If clamping fingers 210 do not engage compact disc
104 or against adaptor 240, rotation of shafts 220 and 442
continues until a stop 452 of link 440 engages a rib 454 of tray
102. As actuating arm 445 moves over inclined surface 622,
actuating arm 444 moves over an inclined surface 612 of lug 610.
Note that the rotatable connection between shaft 442 and link 440
converts the rotational motion of shaft 442 to a linear motion of
link 440, and the rotatable connection between link 440 and shaft
220 converts the linear motion of link 440 to the rotational motion
of shaft 220.
[0035] As tray 102 moves out of printer 100, actuating arm 444 of
clamping assembly 400 engages inclined surface 622 of lug 620,
which exerts a force on actuating arm 444 that rotates shaft 442
relative to tray 102. Rotation of shaft 442 moves link 440
substantially parallel to tray 102 in a direction opposite the
motion of tray 102. Link 440 then rotates shaft 220 in a second
rotational direction opposite the first rotational direction to
bring clamping fingers 210 out of contact with compact disc 104.
Rotation of shaft 220 in the second rotational direction moves
spring 432 back past the toggle point, shifting the net force to
bias clamping fingers 210 in an open position. Rotation of shafts
220 and 442 continues until a stop 450 of link 440 engages rib 454
of tray 102. As arm 444 moves over inclined surface 622 of lug 620,
arm 446 moves over inclined surface 612 of lug 610.
[0036] It will be appreciated that clamping assembly 400 is not
limited for use with two studs, e.g., studs 218 and 219. Rather
fingers 210 can be used to force the periphery 214 of compact disc
104 against a single stud protruding from the tray surface.
[0037] When compact disc 104 is clamped on tray 102, a fixed
distance d.sub.1 (shown in FIGS. 2A and 2B) between a predetermined
first point on tray 102 that substantially coincides with center
point 224 and a predetermined second point 258 located on axis 108
is known. This enables measurement of the dimension r of compact
disc 104 using sensor 310. Note that the predetermined first and
second points are located within a slot 260 of tray 102 that is
disposed along axis 108, where the predetermined second point 258
is adjacent an end of slot 260.
[0038] To measure the dimension r, carriage is positioned so that
sensor 310 is aligned with axis 108, and tray 102 is positioned so
that sensor 310 is aligned with point 258. Tray 102 is then moved
into printer 100 while carriage 110 remains stationary. Meanwhile,
sensor 310 emits a beam of light into slot 260 along axis 108 and
does not detect anything because slot 260 does not reflect any of
the light. When the beam of light encounters periphery 212 of
compact disc 104, compact disc 104 reflects the beam of light, and
receiver 314 captures the reflected light 318. Sensor 310 then
sends a signal to controller 320 of printer 100 indicating the
detection of periphery 212. If no disc is detected when tray 102
arrives at a position in which the beam of light is aligned with
the predetermined second point 258, sensor 310 sends a signal to
controller 320 indicating that there is no disc on tray 102. For an
alternative embodiment, sensor 310 can be aligned with a point 262
located on axis 108 adjacent an opposite end of a slot 260, as
shown in FIGS. 2A and 2B. In this embodiment, measurement of
dimension r is accomplished as just described, except that tray 102
is moved out of printer 100 to move the light beam along axis
108.
[0039] In some embodiments, a stepping motor moves tray 102, where
a number of rotations of the stepper motor is correlated to a
distance d.sub.2 moved by tray 102 in moving from where sensor 310
aligns with point 258 to periphery 212 of the compact disc 104. In
these embodiments, controller 320 counts the number of rotations
made by the stepper motor and subsequently computes the distance
d.sub.2 moved by tray 102. Controller 320 then computes the
dimension r by subtracting d.sub.2 from d.sub.1. Controller then
determines the type of compact disc by comparing the dimension r to
dimensions of known compact disc types stored in a look-up table of
the controller. For example, a particular dimension r specifies a
square or rectangular compact disc with a half side length r,
another a circular compact disc of radius r, etc. For other
embodiments, controller sends the d.sub.2 and d.sub.1 measurements
to the computer 160 for calculation of the dimension r and
determination of the disc type.
[0040] For another embodiment of the present invention, sensor 310
is used to perform a calibration method for locating the center 224
of compact disc 104 while compact disc 104 is clamped on tray 102.
The position of center 224 is stored, for example, in a
non-volatile memory of controller 320 for use during printing to
ensure that the printed image is located properly on the surface of
compact disc 104.
[0041] A method of locating the center 224 is best described with
reference to FIG. 7, which illustrates compact disc 104 clamped to
tray 102. To locate the center 224, tray 102 and carriage 110 are
positioned so that sensor 310 emits a light beam onto a point 710
located on the periphery 212 of the compact disc that is a distance
Ex from the axis 108. Tray 102 is then moved into printer 100, with
carriage 110 at a fixed position, so that the light beam moves
substantially parallel to the axis 108 along a chord 715 of the
compact disc, stopping at a point 720 on the periphery 212. The
center 722 of chord 715, and thus the center of compact disc 104 in
the direction of axis 108 (or the direction of motion of tray 102),
is located on chord 715 halfway between points 710 and 720.
[0042] Tray 102 and carriage 110 are then positioned so that sensor
310 emits a light beam onto a point 730 located on the periphery
212 that is a distance Ey from axis 298, as shown in FIG. 7.
Carriage 110 is then moved across compact disc 104 substantially
perpendicular to the direction of motion of tray 102, with tray 102
at a fixed position, so that the light beam moves substantially
parallel to the axis 298 along a chord 735 of the compact disc,
stopping at a point 740 on the periphery 212. The center 742 of
chord 735 and thus the center of compact disc 104 in the direction
of axis 298 (or the direction substantially perpendicular to the
motion of tray 102) is located is located on chord 735 halfway
between points 730 and 740. The center 224 is then located at the
distance Ey from center 742 of chord 735 in the direction of axis
108, and the distance Ex from center 722 of chord 715 in the
direction of axis 298.
[0043] The chords 735 and 715 respectively correspond to x.sub.p
and y.sub.p coordinate axes of the coordinate system of a bit map
of a printer driver on computer 160 corresponding to the printer
100, whereas axes 298 and 108 respectively correspond to x.sub.t
and y.sub.t coordinate axes of tray 102. The distances Ex and Ey
are stored in controller 320 and are used to transform the x.sub.p
and y.sub.p coordinate axes to the x.sub.t and y.sub.t coordinate
axes. That is, by translating the origin 750 of the x.sub.p and
y.sub.p coordinate axes by the distance Ex along the x.sub.p axis
and the distance Ey along the y.sub.p axis. This acts to properly
locate the printed image on compact disc 104.
[0044] For another embodiment of the present invention, sensor 310
is used to determine whether or not compact disc 104 is clamped.
This involves positioning tray 102 and carriage 110 so that sensor
310 emits a light beam onto a predetermined point 275 on tray 102,
as shown in FIGS. 2A and 2B. When compact disc 104 is clamped,
point 275 coincides with sensing region 211 of one or more of the
clamping fingers 210, as shown in FIGS. 2A and 2B. Sensing surface
211 reflects the beam of light and receiver 314 captures the
reflected light. Sensor 310 then sends a signal to controller 320
of printer 100 indicating that compact disc 104 is clamped.
[0045] FIG. 8 illustrates a clamping error that can be detected
with embodiments of the present invention. In FIG. 8, clamping
fingers 210 have been actuated for clamping against periphery 212,
but clamping fingers 210 are not in engagement with periphery 212.
As such, the biasing force exerted on clamping fingers 210 by
spring 432 moves sensing surface 211 of clamping fingers 210 past
point 275 so that point 275 coincides with a portion of slot 280 in
which the respective clamping finger moves, as shown in FIG. 8.
Therefore, when sensor 310 emits the light beam onto point 275, the
light beam is not reflected, as it is being emitted into slot 280.
Sensor 310 then sends a signal to controller 320 of printer 100
indicating a clamping error. If clamping fingers fail to actuate
into their clamping position, sensing surface 211 does not appear
in slot 280, and again, the beam of light is emitted into slot 280
at point 275 and is not reflected.
[0046] FIG. 9 illustrates clamping of compact disc 104 according to
another embodiment of the present invention. To clamp compact disc
104 to tray 102, a single clamping finger 210 is moved against
periphery 214 to push outer periphery 212 against stationary studs
920 and 922 protruding from surface 217 of the tray. This clamps
compact disc 104 between clamping finger 210 and stationary studs
920 and 922. For other embodiments, a single stationary stud can be
used in place of stationary studs 920 and 922. An adaptor, such as
adaptor 240, can be disposed between studs 920 and 922 and outer
periphery 212 when compact disc is of a different size and/or
shape. For other embodiments, studs 920 and 922 are positioned as
described above for studs 290 and 291 of FIG. 2A or studs 292 and
293 of FIG. 2B. Note that clamping finger 210 moves in the slot
260. Also clamping errors and verification of clamping can be
accomplished using sensor 310, as described above. That is,
reflecting beam of light 316 off sensing surface 211 indicates that
compact disc is clamped. For a clamping error, beam of light 316 is
emitted into slot 260 and cannot be reflected, indicating a
clamping error.
CONCLUSION
[0047] Apparatus and methods are provided for compact disc
printers. For one embodiment, at least one clamping finger of a
movable tray of a compact disc printer pushes against an outer
periphery of a compact disc disposed on a surface of the tray to
clamp the compact disc between the clamping finger and a pair of
studs that protrude from the surface of the tray and engage a
periphery of a hole passing through a center of the compact disc.
Using a pair of studs to engage the periphery of the hole passing
through a center of the compact disc acts to ensure that
successively clamped compact discs are positioned at substantially
the same location on tray. For another embodiment, a sensor is
disposed on a carriage of the printer for moving an ink jet
cartridge attached thereto across the compact disc to deposit an
image on the compact disc. The sensor can be used to determine the
presence of a compact disc on the tray, whether the compact disc is
clamped to the tray, and a dimension of the compact disc, and to
perform a calibration method.
[0048] Although specific embodiments have been illustrated and
described herein, it will be appreciated by those of ordinary skill
in the art that any arrangement that is calculated to achieve the
same purpose may be substituted for the specific embodiments shown.
Many adaptations of the invention will be apparent to those of
ordinary skill in the art. For example, the clamping mechanisms
described above can be used for compact disc printers utilizing a
thermal transfer head in conjunction with a print ribbon in
addition to ink jet disc printers. It will be appreciated that
clamping assembly 400 is not limited for use with two studs, e.g.,
studs 218 and 219. Rather fingers 210 can be used to force the
periphery 214 of compact disc 104 against a single stud protruding
from the tray surface. Moreover, sensor 310 can be used to perform
the methods described above, such as the calibration method, the
method of measuring the dimension r of the compact disc 104, the
method for determining whether compact disc 104 is clamped, etc.,
when the compact disc is clamped between one or more clamping
fingers 210 and a single stud that protrudes from the surface of
tray 102 and engages periphery 214 of the compact disc 104.
Accordingly, this application is intended to cover any adaptations
or variations of the invention. It is manifestly intended that this
invention be limited only by the following claims and equivalents
thereof.
* * * * *