METHODS FOR DETERMINING AN AMOUNT OF REMAINING PRINT MEDIA IN A PRINTER
Printers and methods are provided for determining an amount of remaining print media in an operating printer. Waveform signal is received from encoder wheel having number (n) of sectors and proximate optical sensor. Waveform signal represents number of sectors (m) that, during measurement time (t), pass by optical sensor as encoder wheel rotates. If media encoder wheel, in response to receiving waveform signal, processor calculates length of remaining print media in media roll at instant time t 2 . If ribbon encoder wheel, in response to receiving waveform signal, processor at least one of calculates length of remaining ribbon in ribbon roll at instant time t 2 or extrapolates the length of the remaining print media from a plurality of data points defining an interpolation equation.
1 . A method for determining an amount of remaining print media in a printer, the method comprising:
receiving a waveform signal from a media encoder wheel having a number (n) of sectors and proximate an optical sensor, the waveform signal representing the number of sectors (m) that, during a measurement time (t), pass by the optical sensor as the encoder wheel rotates; and
in response to receiving the waveform signal, calculating a length of the remaining print media in a media roll at an instant time t 2 (Media length2 ).
2 . The method according to claim 1 , wherein if the remaining print media comprises non-continuous print media, the method further comprises:
receiving a signal representative of an individual print medium length; and
calculating a quantity of individual print medium printable from the length of the remaining print media by dividing the length of the remaining print media (Media length ) by the individual print medium length.
3 . The method according to claim 1 , wherein calculating the length of the remaining print media at the instant time t 2 (Media length2 ) comprises:
calculating a difference between an outer diameter of the media roll at an instant time t 1 (d 1 ) and the outer diameter of the media roll at the instant time t 2 (d 2 );
determining a number of rotations of the media encoder wheel (Rot nbr ) during a time interval from t 1 to t 2 ; and
calculating a print media thickness (Th) from the equation:
media
thickness
(
Th
)
=
d
1
-
d
2
2
×
Rot
nbr
;
and
using the following equation:
Media
Lenght
=
π
4
Th
[
d
1
2
-
di
2
]
wherein di comprises the outer diameter of a media core of the media roll.
4 . The method according to claim 3 , wherein, prior to calculating the difference between the outer diameter of the media roll at the instant time t 1 (d 1 ) and the outer diameter of the media roll at the instant time t 2 (d 2 ), the method further comprises calculating the outer diameter (d) of the media roll at the instant time t 1 (d 1 ) and at the instant time t 2 (d 2 ) from an angular speed (ω) and a linear speed (ν) of the media encoder wheel using the following equation:
Media
diameter
:
d
(
mm
)
=
2
(
25.4
v
ω
)
=
2
(
25.4
v
·
(
n
·
t
)
2
π
·
m
)
wherein the linear speed comprises a print speed and the angular speed (ω) of the media encoder wheel is calculated at an instant time tx using the following equation:
Angular
speed
(
ω
)
=
Angle
traveled
Time
taken
=
θ
t
ω
(
rad
s
)
=
θ
t
=
2
π
n
×
m
t
{
with
:
n
number
of
sectors
in
encoder
wheel
m
number
of
sectors
seen
in
t
″
``
time
t
=
measurement
time
5 . The method according to claim 3 , wherein, prior to calculating the difference between the outer diameter of the media roll at the instant time t 1 (d 1 ) and the outer diameter of the media roll at the instant time t 2 (d 2 ), the method further comprises calculating the outer diameter (d) of the media roll at the instant time t 1 (d 1 ) and at the instant time t 2 (d 2 ) from a number of stepper motor steps (i) in a single full revolution of the media encoder wheel using the following equation: outer diameter (d)=i/(dots per inch(DPI)×3.1416).
6 . The method according to claim 3 , further comprising measuring, at depletion of the media roll, the outer diameter (di) of the media core therein to obtain an updated value of di and updating the remaining print media length calculation with the updated value.
7 . The method according to claim 1 , wherein determining an amount of remaining print media comprises determining a determinative amount of remaining print media.
8 . The method according to claim 2 , further comprising generating an alert if the length of the remaining print media, the quantity of individual print media, or a combination thereof, is below a minimum threshold amount.
9 . A method for determining an amount of remaining print media in a printer, the method comprising:
receiving a waveform signal from a ribbon encoder wheel having a number (n) of sectors and proximate an optical sensor, the waveform signal representing the number of sectors (m) that, during a measurement time (t), pass by the optical sensor as the ribbon encoder wheel rotates; and
in response to receiving the waveform signal, calculating a length of the remaining ribbon in a ribbon roll at the instant time t 2 (Ribbon length2 ), the length of the remaining ribbon at the instant time t 2 comprising a length of the remaining print media at the instant time t 2 .
10 . The method according to claim 9 , wherein if the remaining print media comprises non-continuous print media, the method further comprises:
receiving a signal representative of an individual print medium length; and
calculating a quantity of individual print medium printable from the length of the remaining print media by dividing the length of the remaining print media (Media length ) by the individual print medium length.
11 . The method according to claim 9 , wherein calculating the length of the remaining ribbon at the instant time t 2 (Ribbon length ) comprises:
calculating a difference in an outer diameter of the ribbon roll at an instant time t 1 and the outer diameter of the ribbon roll at the instant time t 2 ;
determining a number of rotations (Rot nbr ) of the ribbon encoder wheel during a time interval from t 1 to t 2 ; and
calculating a ribbon thickness (Th) from the equation:
ribbon
thickness
(
Th
)
=
d
1
-
d
2
2
×
Rot
nbr
;
and
using the following equation:
Ribbon
Lenght
=
π
4
Th
[
d
1
2
-
di
2
]
,
wherein di comprises an outer diameter of a ribbon core of the ribbon roll.
12 . The method according to claim 11 , wherein, prior to calculating the difference between the outer diameter of the ribbon roll at the instant time t 1 and the outer diameter of the ribbon roll at the instant time t 2 , the method further comprises calculating the outer diameter (d 1 ) of the ribbon roll at the instant time t 1 and the outer diameter (d 2 ) at t 2 from an angular speed (ω) and a linear speed (ν) of the ribbon encoder wheel and using the following equation:
Ribbon
diameter
:
d
(
mm
)
=
2
(
25.4
v
ω
)
=
2
(
25.4
v
·
(
n
·
t
)
2
π
·
m
)
wherein the linear speed comprises a print speed and the angular speed (ω) of the ribbon encoder wheel is calculated at an instant tx using the following equation:
Angular
speed
(
ω
)
=
Angle
traveled
Time
taken
=
θ
t
ω
(
rad
s
)
=
θ
t
=
2
π
n
×
m
t
{
with
:
n
number
of
sectors
in
encoder
wheel
m
number
of
sectors
seen
in
t
″
``
time
t
measurement
time
13 . The method according to claim 11 , wherein, prior to calculating the difference between the outer diameter of the ribbon roll at the instant time t 1 and the outer diameter of the ribbon roll at the instant time t 2 , the method further comprises calculating the outer diameter (d 1 ) of the ribbon roll at the instant time t 1 and the outer diameter (d 2 ) at t 2 from a number of stepper motor steps (i) during a single full revolution of the ribbon encoder wheel and using the following equation: Diameter (d)=i/(dots per inch(DPI)×3.1416).
14 . The method according to claim 11 , further comprising measuring, at depletion of the ribbon roll, the outer diameter (di) of the ribbon core therein to obtain an updated value of di and updating the remaining ribbon length calculation with the updated value.
15 . The method according to claim 9 , wherein determining an amount of remaining print media comprises determining a determinative amount of remaining print media.
16 . The method according to claim 10 , further comprising generating an alert if the length of the remaining ribbon, the length of the remaining print media, the quantity of individual print media, an amount of print media printable therefrom, or a combination thereof, is below a minimum threshold amount.
17 . A method for determining an amount of remaining print media in a printer, the method comprising:
receiving a waveform signal from a ribbon encoder wheel having a number (n) of sectors and proximate an optical sensor, the waveform signal representing the number of sectors (m) that, during a measurement time (t), pass by the optical sensor as the ribbon encoder wheel rotates; and
in response to receiving the waveform signal, extrapolating the length of the remaining print media from a plurality of data points defining an interpolation equation.
18 . The method according to claim 17 , wherein, prior to extrapolating the length of the remaining print media, the method comprises:
obtaining the plurality of data points by:
calculating a difference in an outer diameter of the ribbon roll at a first instant time tn and the outer diameter of the ribbon roll at a second instant time tn (Rd_used);
determining an amount of print media printed (Md_used) during a time interval from the first instant time tn to the second instant time tn;
repeating the steps at successive time intervals of calculating the difference in the outer diameter of the ribbon roll and determining the amount of print media printed,
wherein each data point comprises the difference in the outer diameter of the ribbon roll and the amount of print media printed (Md_used) during the time interval and during successive time intervals; and
defining an interpolation equation from the plurality of data points, the interpolation equation defining a relationship between the Md_used per Rd_used:
Md usedx =F ( Rd _ usedx ).
19 . The method according to claim 18 , wherein, prior to calculating the difference between the outer diameter of the ribbon roll at the instant time t 1 and the outer diameter of the ribbon roll at the instant time t 2 , the method further comprises calculating the outer diameter (d 1 ) of the ribbon roll at the instant time t 1 and the outer diameter (d 2 ) at t 2 from one of the following:
(a) a number of stepper motor steps (i) during a single full revolution of the ribbon encoder wheel and using the following equation: Diameter (d)=i/(dots per inch(DPI)×3.1416); and
(b) an angular speed (ω) and a linear speed (ν) of the ribbon encoder wheel and using the following equation:
Ribbon
diameter
:
d
(
mm
)
=
2
(
25.4
v
ω
)
=
2
(
25.4
v
·
(
n
·
t
)
2
π
·
m
)
wherein the linear speed comprises a print speed and the angular speed (ω) of the ribbon encoder wheel is calculated at an instant tx using the following equation:
Angular
speed
(
ω
)
=
Angle
traveled
Time
taken
=
θ
t
ω
(
rad
s
)
=
θ
t
=
2
π
n
×
m
t
{
with
:
n
number
of
sectors
in
encoder
wheel
m
number
of
sectors
seen
in
t
″
``
time
t
measurement
time
20 . The method according to claim 17 , wherein if the remaining print media comprises non-continuous print media, the method further comprises:
receiving an individual print medium length; and
calculating a quantity of individual print medium printable from the length of the remaining print media by dividing the length of the remaining print media (Media length ) by the individual print medium length.