U.S. patent application number 09/871226 was filed with the patent office on 2001-11-01 for encoded device for a toner cartridge.
This patent application is currently assigned to Lexmark International, Inc.. Invention is credited to Curry, Steven Alan, Newman, Benjamin Keith, Ward, Earl Dawson II, Wright, Phillip Byron.
Application Number | 20010036368 09/871226 |
Document ID | / |
Family ID | 27084208 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010036368 |
Kind Code |
A1 |
Curry, Steven Alan ; et
al. |
November 1, 2001 |
Encoded device for a toner cartridge
Abstract
One aspect of the invention is the invention is directed to a
toner cartridge including a sump for carrying a supply of toner. An
agitator is rotatably mounted in the sump, and the agitator has a
first end and a second end. An encoded wheel is coupled to the
first end of the agitator. The encoder wheel is structured and
adapted to include a first preselected cartridge characteristic
indicia having a first extent, a stop indicia having a second
extent larger than the first extent and a start indicia having a
third extent larger than the second extent. Each indicia may be in
the form of a slot. Preferably, the start indicia is positioned
between about a 5:00 o'clock position and a 6:00 O'clock postition.
The stop indicia is positioned at about a 9:00 o'clock position. At
least one preselected cartridge characteristic indicia is
positioned between the start indicia and the stop indicia. At least
one measurement indicia is located between about 200 degrees and
about 230 degrees in a clockwise direction from the 6:00 o'clock
position.
Inventors: |
Curry, Steven Alan;
(Nicholasville, KY) ; Newman, Benjamin Keith;
(Lexington, KY) ; Ward, Earl Dawson II; (Richmond,
KY) ; Wright, Phillip Byron; (Lexington, KY) |
Correspondence
Address: |
John A. Brady
Lexmark International, Inc.
Intellectual Property Law Dept.
740 West New Circle Road
Lexington
KY
40550
US
|
Assignee: |
Lexmark International, Inc.
|
Family ID: |
27084208 |
Appl. No.: |
09/871226 |
Filed: |
May 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09871226 |
May 31, 2001 |
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09557096 |
Apr 21, 2000 |
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09557096 |
Apr 21, 2000 |
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09415620 |
Oct 12, 1999 |
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6169860 |
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09415620 |
Oct 12, 1999 |
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08975389 |
Nov 20, 1997 |
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6009285 |
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08975389 |
Nov 20, 1997 |
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08768257 |
Dec 17, 1996 |
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5995772 |
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08768257 |
Dec 17, 1996 |
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08602648 |
Feb 16, 1996 |
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5634169 |
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Current U.S.
Class: |
399/12 ; 399/13;
399/27 |
Current CPC
Class: |
G03G 15/0858 20130101;
G03G 21/1896 20130101; G03G 15/0889 20130101; G03G 15/0856
20130101; G03G 15/0896 20130101; G03G 15/0822 20130101; G03G
2221/1838 20130101 |
Class at
Publication: |
399/12 ; 399/13;
399/27 |
International
Class: |
G03G 015/00; G03G
015/08 |
Claims
What is claimed is:
1. A toner cartridge, comprising: a sump for carrying a supply of
toner; an agitator rotatably mounted in said sump, said agitator
having a first end and a second end; and an encoded wheel coupled
to said first end of said agitator, said encoded wheel being
structured and adapted to include a first preselected cartridge
characertistic indicia having a first extent, a stop indicia having
a second extent larger than said first extent and a start indicia
having a third extent larger than said second extent.
2. The toner cartridge of claim 1, wherein said encoded wheel
includes relative indicia positions defined in relation to a clock
face for said first preselected cartridge characteristic idicia
said stop indicia and said start indicia.
3. The toner cartridge of claim 2, wherein said start indicia is
positioned between about a 5:00 o'clock position and a 6:00 o'clock
position, said stop indicia is positioned at about a 9:00 o'clock
position and said first preselccted cartridge characteristic
indicia is positioned between said start indicia and said stop
indicia.
4. The toner cartridge of claim 3, further comprising a plurality
of equally spaced preselected cartridge characteristic indicia
positioned between said start indicia and said stop indicia.
5. The toner cartridge of claim 4, further comprising a plurality
of measurement indicia located between about 200 degrees and about
230 degrees in a clockwise direction from said 6:00 o'clock
position.
6. The toner cartridge of claim 5, wherein said plurality of
measurement indicia comprise a first slot having a first trailing
edge, a second slot having a second trailing edge and a third slot
having a third trailing edge, wherein said first trailig edge is
located at about 200 degrees in a clockwise direction from said
6:00 o'clock position, said second training edge is located at
about 215 degrees in a clockwise direction from said 6:00 o'clock
position and said third trailing edge is located at about 230
degrces in a clockwise direction from said 6:00 o'clock
position.
7. The toner cartridge of claim 6, wherein no further indicia is
located between said stop indicia and said first slot.
8. The toner cartridge of claim 7, wherein no further indicia is
located between said third slot and said start indicia.
9. The toiler cartridge of claim 5, wherein each of said inidicia
comprises a slot formed in said encoded wheel.
10. A toner cartridge, comprising: a a sump for carrying a supply
of toner; an agitator rotatably mounted in said sump, said agitator
having a first end and a second end; and an encoded wheel coupled
to said first end of said agitator, said encoded wheel having
preprogrammed indicia positioned at locations defined in relationl
to a clock face said preprogrammed inidicia including a start
indicia positioned between about a 5:00 o'clock position and a 6:00
o'clock position, a stop indicia positioned at about a 9:00 o'clock
position, at least one preselectcd cartridge characteristic indicia
positioined between said start indicia and said stop indicia, and
at least one measurement indicia located between about 200 degrees
and about 230 degrees in a clockwise direction from said 6:00
o'clock position.
11. The toiler cartridge of claim 10, wherein each of said indicia
comprises a slot formed in said encoded wheel.
12. The toner cartridge of claim 10, whierein said at least one
preselected cartridge characteristic indicia comprises a plurality
of equally spaced preselected cartridge characteristic indica
positioned between said start indicia and said stop indicia.
13. THe toner cartridge of claim 10, wherein said at least one
measurement indicia comprises a plurality of measurement indicia,
said plurality of measurement indicia including a first slot having
a first trailing edge, a second slot having a second trailing edge
and a third slot having a third trailing edge, wherein said first
trailing edge is located at about 200 degrees in a clockwise
direction from said from said 6:00 o'clock position and said second
trailing edge is located at about 215 degrees in a clockwise
direction from said 6:00 o'clock position and said third trailing
edge is located at about 230 degrees in a clockwise direction from
said 6:00 o'clock position.
14. The toner cartridge of claim 13, wherein no further indicia is
located between said stop indicia and said first slot.
15. The toner cartridge of claim 13, wherein no further indicia is
located between said third slot and said start indicia.
16. An encoded wheel for a toner cartridge comprising a plate
having preprogrammed indicia positioned at locations defined in
relation to a clock face, said preprogrammed indicia including a
start indicia positioned between about a 5:00 o'clock position and
a 6:00 o'clock position, a stop indicia positioned at about a 9:00
o'clock position, at least one preselected cartridge characteristic
indicia positioned between said start indicia and said stop indicia
and at least one measurement indicia located between about 200
degree and about 230 degrees from said 6:00 o'clock position.
17. The encoded wheel of claim 16, wherein each said indicia
comprises a slot.
18. An encoded wheel for a toner cartridge comprising a plate
having preprogrammed indicia positioned as locations defined in
relation to a clock face, said preprogrammed indicia including a
first slot positioned between about a 5:00 o'clock position and a
6:00 o'clock position a second slot positional at about a 9:00
o'clock position a third slot positioned between said first slot
and said second slot, and each of a fourth slot, a fifth slot and a
sixth slot sequentially located in a clockwise direction between
about 200 degrees and about 230 degrees from said 6:00 0'clock
position, and wherein no further slot is located between said
second slot and said fourth slot and no further slot is located
between said sixth slot and said first slot.
19. A toner cartridge comprising a rotatable wheel having
preprogrammed indicia positioned at locations defined in relation
to a clock face, said preprogrammed indicia including a first slot
positioned between about a 5:00 o'clock positioned and a 6:00
o'clock position a second slot positioned at about a 9:00 o'clock
position, a third slot positioned between said first slot and said
second slot, and each of a fourth slot, a fifth slot and a sixth
slot sequentially located in a clockwise direction between about
200 degrees and about 230 degrees from said 6:00 o'clock position,
and wherein no further slot is located between said second slot and
said fourth slot and no further slot is located between said sixth
slot and said first slot.
20. The toner cartridge of claim 19, wherein said third slot is one
of a plurality of slots located between said first slot and said
second slot.
Description
[0001] This application is a continuation of U.S. Pat. application
Ser. No. 08/975,389 filed on Nov. 20, 1997, which is a continuation
of U.S. Pat. application Ser. No. 08/768,257 filed on Dec. 17,
1996, which is a continuation-in-part of U.S. Pat. application Ser.
No. 08/602,648 filed on Feb. 16, 1996, now U.S. Pat. No.
5,634.169.
[0002] A portion of the disclosure of this patent document contains
material which is subject to copyright protection. The copyright
owner has no objection to the facsimile reproduction by anyone of
the patent document or the patent disclosure, as it appears in the
Patent and Trademark Office patent file or records, but otherwise
reserves all copyright rights whatsoever.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to Electrophotographiic (EP)
machines and more particularly relates to methods and apparatus
associated witih replaceable supply cartridges for such machines
wherein information concerning thle cairtridge is provided to the
machine to promote correct and efficient operation thereof.
[0005] 2. Description of Related Art
[0006] Many Electrophotographic output device (e.g., laser
printers, copiers, fax machines etc.) manufacters such as Lexmark
International, Inc., have traditionally required information about
the EP cartridge to be available to the output device such that the
control of the machine can be altered to yield the best print
quality and longest cartridge life.
[0007] The art is replete withr devices or entry method to inform
the EP machine about specific EP cartridge characteristics. For
example, U.S. Pat. No. 5,208,631 issued on May 4, 1993, discloses a
techinique to identify colormetric properties of toner contained
within a cartridge in a reproduction machine by imbedding in a PROM
within the cartridge specific coordinates of a color coordinate
system for mapping color data.
[0008] In other prior art, for example U.S. Pat. No. 5,289,242
issued on Feb. 22, 1994, there is disclosecd a method and system
for indicating the type of toner print cartridge which has been
loaded into an EP printer. Essentially, this comprises a conductive
strip mounted on the cartridge for mating with contacts in the
machine when the lid or cover is closed. The sensor is a two
positioin switch which tells the user the type of print cartridge
which has been loaded into the priniter. While this method is
effective, the amount of information that can be provided to the
machine is limited.
[0009] In still other prior art, such as in U.S. Pat. No. 5,365,312
issued on Nov. 15, 1994 a memory chip containing information about
the current fill status or other status data is retained. The
depleted status of print medium is supplied by counting consumption
empirically. The average of how much toner is required for toning a
charge image is multiplied by the number of revolutions of the
charge image carricr or by the degree of inking of the charaters
via an optical sensor. In either method, the count is less than
accurate and depends upon average ink coverage on the page, or
alternatively, the charater density which can change dramatically
due to font selection. Therefore at best, the consumption count
lacks accuracy.
[0010] The literature suggests several methods for detecting toner
level in a laser printer. Most of these methods detect a low toner
condition or whether toner is above or below a fixed level. Few
methods or apparatus effectively measure the amount of unused toner
remaining. As an example, Lexmark.RTM. printers currently employ an
optical technique to detect a low toner condition. This method
attempts to pass a beam of light through a section of the toner
reservoir onto a photo sensor. Tonor blocks the beam until its
level drops below a preset height.
[0011] Another common method measures the effect of toner on a
rotating agitator or toner paddle which stirs and moves the toner
over a sill to present it to a toner adder roll, then developer
roll and ultimately the PC Drum. The paddle's axis of rotation is
horizontal. As it proceeds through it's gull 360 degree rotation
the paddle enters and exits the toner supply. Between the point
where the paddle contacts the toner surface and the point whvere it
exits the toner, the toner resists the miotion of the paddle and
produces a torque load on the paddle shaft. Low toner is detectecd
by either 1) detecting if the torque load caused by the presence of
toner is below a given threshold at a fixed paddle location or 2)
detecting if the surface of the toner is below a fixed height.
[0012] In either method there is a driving member supplying drive
torque to a driven member (the paddle) which experiences a load
torque whlen contacting the toner. Some degree of freedom exists
for thcse two members to rotate independently of each other in a
carefully defined manner. For the first method 1) above, with no
load applied to the paddle, both members rotate together. However,
when loaded the paddle lags the driving member by an angular
distance that increases with increasing load. In the second method
2), the unloaded paddle leads the rotation of the driving member,
under the force of a spring or gravity. When loaded (i.e., the
paddle contacts the surface of the toner), the driving and driven
members come back into alignment and rotate together. By measuring
the relative rotational displacement of the driving and driven
members (a.k.a. phase difference) at an appropriate phase in the
paddle's rotation, the presence of toner can be sensed.
[0013] In the prior art, this relative displacement is sensed by
measuring the phase difference of two disks. The first disk is
rigidly attached to a shaft that provides the driving torque for
the paddle. The second disk is rigidly attached to the shaft of the
paddle and in proximity to the first disk. Usually both disks have
matching notches or slots in them. The alignment of the slots or
notches, that is how much they overlap, indicates the phase
relationship of the disks and therefore the phase of the driving
and driven members.
[0014] Various art showing the above methods and variations are set
forth below.
[0015] In U.S. Pat. No. 4,003,258, issued on Jan. 18, 1977 to Ricoh
Co., is disclosed the use of two disks to measure toner paddle
location relative to the paddle drive shaft. When the paddle
reaches the top of its rotation the coupling between paddle and
drive shaft allows the paddle to free fall under the force of
gravity until it comes to rest on the toner surface or at the
bottom of its rotation. Toner low is detected if the angle through
which the paddle falls is greater than a fixed amounts (close to
180 degrees). A spring connects the two disks, but the spring is
not used for toner dectection. It is used to fling toner from the
toner reservior to the developer.
[0016] In U.S. Pat. No. 5,216,462, issued to Oki Electric Co., Jun.
1, 1993, is described a system where a spring connects two disks so
that the phase separation of the disks indicates torque load on the
paddle. An instability is noted in theis type of system. If further
describes a system similar to the Patent above where the paddle
free falls from its top dead position to the surface of the toner.
The position of the paddle is sensed through magnetic coupling to a
lever outside of the toner reservoir. This lever activiates an
optical switch when the paddle is near the bottom of its rotation.
A low toner indication results when the time taken for the paddle
to fall from the top dead center to the bottom of the reservoir, as
sensed by the optical switch, is less than a given value.
[0017] In U.S. Pat. No. 4,592,642, issued on Jun. 3, 1986 to
Minolta Camera Co., is described a system that does not use the
paddle directly to measure toner, but instead uses the motion of
the paddle to lift a "float" above the surface of the toner and
drop it back down on top of the toner surface. A switch is
activatced by tile "float" when in the low toner position. If tile
"float" spends a substantial amount of time in the low toner
position the device signals low toner. Although the patent implies
theat the amount of toner in the reseivoir can be measured, the
description indicates that it behaves in a very non-linear, almost
binary way to merely detect a toner low state.
[0018] U.S. Pat. No. 4,989,754, issued on Feb. 5, 1991 to Xerox
Corp., differs from the others in that there is no internal paddle
to agitate or deliver toner. Instead the whole toner reservoir
rotates about a horizontal axis. As the toner inside rotates with
the reservoir it drags a rotatable lever along with it. When the
toner level becomes low, the lever, no longer displaced from its
home position by the movement of the toner, returns to its home
position under the force of gravity. From this position the level
activates a switch to indicate low toner.
[0019] In still another U.S. Pat. No. 4,711,561, issued on Dec. 8,
1987 to Rank Xerox Limited this patent describes a means of
detecting when a waste toner tank is full. It employs a float that
gets pushed upward by waste toner fed into the tank from the
bottom. The float activiates a switch when it reaches the top of
the tank.
[0020] U.S. Pat. No. 5,036,363, issued on Jul. 30, 1991 to Fujitsu
Limited, describes the use of a commercially available vibration
sensor to detect the presence of toner at a fixed level. The patent
describes a simple timing method for ignoring the effect of the
sensor cleaning mechanism of the sensor output.
[0021] U.S. Pat. No. 5,349,377, issued on Sep. 20, 1994 to Xerox
Corp., discloses an algorithm for calculating toner usage and hence
amount of toner remaining in the reservoir by counting black pixels
and weighting them for toner usage based on pixels per unit area in
the pixel's neighborhood. This is unlike the inventive method and
apparatus disclosed hereinafter.
SUMMARY OF THE INVENTION
[0022] The present invention is related to apparatus and method for
represently cartridge characteristic information by an encoded
device, and for reading such information from the encoded
device.
[0023] One aspect of the invention is directed to a toner cartridge
including a sump for carrying a supply of toner. An agitortor is
rotatably mounted in the sump, and the agiator has a first end and
a second end. An encoded wheel is coupled to the first end of the
agitator. The encoder wheel is structured and adapted to include a
first preselected cartridge characteristic indicia having a first
extent, a stop indicia having a second extent larger than the first
extent and a start indicia having a third extent larger than the
second extent. In a most preferred embodiments, each indicia is in
the form of a slot.
[0024] Another aspect of the invention is directed to a toner
cartridge including a sump for carrying a supply of toner. An
agitator is rotatable mounted in the sump. The agitator has a first
end and a second end. An encoder wheel is coupled to the first end
of the agitator. The encoded wheel includes preprogrammed indicia
positioned at locations defined in relation to a clock face. The
preprogrammed indicia include a start indicia positioned between
about a 5:00 o'clock position and a 6:00 o'clock position, a stop
indicia positioned at about a 9:00 o'clock position, at least one
preselected cartridge characteristic indicia positioned between the
start indicia and the stop indicia, and at least one measurement
indicia located between about 200 degrees and about 230 degrees in
a clockwise direction from the 6:00 o'clock position.
[0025] Other features and advantages of the invention may be
determined from the drawings and detailed description of the
invention that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic side elevational view illustrating the
paper path in a typical electrophotographic machine, in the
illustrated instance a printer, and showing a replacement supply EP
cartridge, constructed in accordance with the present invention,
and the manner of insertion thereof into the machine;
[0027] FIG. 2 is a fragmentary, enlarged, simplified, side
elevational view of the cartridge illustrated in FIG. 1, and
removed from the machine of FIG. 1;
[0028] FIG. 3 is a fragmentary perspective view of the interior
driven parts or the EP cartridge illustrated in FIGS. 1 and 2,
including the encoder wheel and its relative position with regard
to the drive mechanism for the cartridge interior driven parts;
FIG. 4 is an enlarged fragmentary perspective view of the
agitator/paddle drive for the toner sump, and illustrating a
portion of the torque sensitive coupling between the drive gear and
the driven shaft for the agitator/paddle:
[0029] FIG. 5A is a fragmentary view similar to FIG. 4, except
illustrating another portion of the torque sensitive coupling for
coupling the driven shaft for the agitator/paddle, through the
coupling to the drive gear, and FIG. 5B depicts the reverse side of
one-half of the torque sensitive coupling, and that portion which
connects to the agitator/paddle shaft:
[0030] FIG 6 is a simplified electrical diagram for the machine of
FIG. 1 and illustrating the principal parts of the electrical
circuit;
[0031] FIG. 7 is an enlarged side elevationial view of the encoder
wheel employed in accordance with the present invention, and viewed
from the same side as shown in FIG. 2, and from the opposite side
as shown in FIG. 3;
[0032] FIG. 8A is a first portion of a flow chart illustrating the
code necessary for machine start up and the reading of information
coded on the encodce wheel;
[0033] FIG. 8B is a second portion of the flow chart of FIG. 8A
illustrating the measurement of toner level in the toner sump;
[0034] FIG. 9 is a graphical display of the torque curves for three
different toner levels within the sump, and at various positions of
the toner paddle relative to top dead center or the home position
of the encoder wheel;
[0035] FIG. 10 is a perspective view of an encoder wheel with novel
apparatus for blocking off selected slots in the encoder wheel for
coding the wheel with EP cartridge information.
[0036] FIGS. 11A-11E represent in flow chart form an alternative
method for machine start up, the reading of information coded on
the encoder wheel and the measurement of toner level in the toner
sump;
[0037] FIG. 12 is a sectional view of an encoder wheel and a
schematic representation of an alternative Hall effect
reader/sensor of the invention;
[0038] FIG. 13 is a sectional view of an encode wheel and a
schematic representation of an alternative reflective reader/sensor
of the invention;
[0039] FIG. 14 is a fragmentary side elevational view of a portion
of the encode wheel of FIG. 12 and taken along line 13-13 of FIG.
12;
[0040] FIG. 15 is a fragmentary side elevational view or an encoder
wheel with a cam surface implementation and a cam follower
reader/sensor mechanism; and
[0041] FIG. 16 is a fragmentary side elevational view of an encoder
wheel with a cam surface implementation and can alternative cam
follower reader/scensor mechanism.
DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
[0042] Turning now to the drawings, and particularly FIG. 1
thereof, a laser printer 10 constructed in accordance with the
present invention, is illlustrated therein. FIG. 1 shows a
schematic side view of the printer 10, illustrating the print
receiving media path 11 and including a replacement supply
electrophotographic (EP) cartridge 30, constructed in accordance
with the present invention. As illustrated, the machine 10 includes
a casing or housing 10a which supports at least one media supply
tray 12, which by way of a picker arm 13 feeds cut sheet of print
receiving media 12a (e.g., paper) into the media path 11 past the
print engine which forms in the present instance part of the
cartridge 30 and through the machine 10. A transport motor dirve
assembly 15 (FIG. 3) affords the driving action for feeding the
media through and between the nips of pinch roller pairs 16-23 into
a media receiving output tray 26.
[0043] In accordance with the invention, and referring now to FIGS.
1 & 2, the cartridge 30 includes an encoder wheel 31 adapted
for coactionm, when the cartridge 30 is nested in its home position
within the machine 10, with an encoder wheel sensor or reader 31a
for conveying or transmitting to the machine 10 information
concerning cartridge characteristics including continuing data
(while the machine is running) concerning the amount of toner
remaining within the cartridge and/or preselected cartridge
characteristics, such as for example, cartridge type or size, toner
capacity, toner type, photoconductive drum type, etc. To this end,
the encoder wheel 31 is mounted, in the illustrated instance on one
end 32a of a shaft 32, which shaft is coaxially mounted for
rotation with the encoder wheel 31, extending radially from the
shaft 32 and axially along the sump 33 is a toner agitator or
paddle 34. The toner 35 level for a cartridge (depending upon
capacity) is generally as shown extending from approximately the
9:00 position and then counter clockwise to the 3:00 position. As
the paddle 34 rotates counter clockwise in the direction o the
arrow 34a, toner tends to be moved over the sill 33a of the sump
33. (The paddle 34 is conventionally provided with large openings
34b, FIG. 3, to provide lower resistance thereto as it passes
through the toner 35.) As best shown in FIGS. 2 & 3, the toner
that is moved over the sill 33a, is presented to a toner adder roll
36, which interacts in a known manner with a developer roll 37 and
then a photo conductive (PC) drum 38 which is in the media path 11
for applying text and graphical information to the print receiving
media 12a presented thereto in the media path 11.
[0044] Referring now to FIG. 3, the motor transport assembly 15
includes a drive motor 15a. which is coupled through suitable
gearing and drive take-offs 15b to providle multiple and differing
drive rotationis to, for example, the PC drum 38 and a drive train
40 for the developer roll 37, the toner adder roll 36 and through a
variable torque arrangement, to one end 32b of the shaft 32. The
drive motor 15a may be of any convenient type, e.g., a stepping
motor or in the preferred embodiment a brushless DC motor. While
any of several types of motors may be employed for the drive,
including stepping motors, a brushless DC motor is ideal because of
the availability of either hall effect or frequency generated
feedback pulses which present measurable and finite increments of
movement or the motor shalt. The feedback accounts for a
predetermined distance measurement, which will be referred to as an
increment rather than a `step` so as not to limit the drive to a
stepping motor.
[0045] The drive train 40, which in the present instance forms part
of the cartridge 30, includes driven gear 40a, which is directly
coupled to the developer roll 37, and through an idler gear 40b is
coupled to the toner adder roll 36 by gear 40c. Gear 40c in turn
through suitable reduction gears 40d and 40e drives final drive
gear 41. In a manner more fully explained below with reference to
FIGS. 5 & 6 the drive gear 41 is coupled to the end 32b of
shaft 32 through a variable torque sensitive coupling.
[0046] In FIG. 3 the gear 41 is shown as including an attached web
or flange 42 connected to a collar 43 which acts as a bearinig
permitting, absent restraint, free movement of the gear 41 and its
web 42 about the end 32b oF tlie shiall 32. Refferring now to FIG.
4, the driving half of the variable torque sensitive coupling is
mounlied on the web 42 of the gear 41. To this end the driving half
of the coupling includes a coiled torsion spring 44, one leg 44a of
which is secured to the web 42 of the gear 41, the other leg 44b of
which is free standing.
[0047] Turning now to FIG. 5A, the other half (driven half) of the
coupling is illustrated therein. To this end, an arbor 45 having a
keyed central opening 46 dimensioned for receiving the keyed (flat)
shiaft end 32b of the shaft 32, is depicted therein. For ease of
understanding, an inset drawling is provided wherein the reverse
side of the arbor 45 is shown. The arbor 45 includes radially
extending ear portions 47a, 47b, the extended terminal ends of
which overlay the flange 48 associatedi with the web 42 of the gear
41. The rear face or back surface 45a of the arbor 45 (see FIG. 5B)
contfronting the web 42, includes depending, reinforcing leg
portions 49a, 49b. A collar 46a abuts the web 42 or the gear 41 and
maintains the remaining portion of the arbor 45 spaced from the web
42 of the gear 41. Also attached to the rear of the back surface
45a of the arbor 45 is a clip 50 which grasps the free standing leg
44b of the spring 44.
[0048] Thus one end 44a (FIG. 4) of the spring 44 is connected to
the web 42 of the geal 41 while the other end 44b of the spring 44
is connected to the arbor 45 which is in turn keyed to the shaft 32
mounted for rotation in and through the sump 33 of the cartridge
30. Therefore the gear 41 is comiected to the shaft 32 through the
spring 44 and the arbor 45. As the gear 41 rotates the end 44b of
the spring presses against the catch 50 in the arbor 45 which tends
to rotate causing the paddle 34 on the shaft 32 to rotate. When the
paddle first engages the toner 35 in the sump 33, the added
resistance causes an increase in torsion and the spring 44 tends to
wind up thereby causing the encoder wheel 31 to lag the rotational
position of the gear 41. Stops 51 and 52 mounted on the flange 48
prevent over winding or excessive stressing of the spring 44. In
instances where the sump 33 is at the fill design level of toner 35
the ears 47a, 47b engage the stops 52 and 51 respectively. The
spring 44 therefore allows the paddle shaft 32 to lag, relative to
the gear 41 and the drive train 40 because or the resistance
encountered against the toner 35 as the paddle 34 attempts to move
through the sump 33. The more resistance encountered because of
toner against the paddle 34, the greater the lag. As shall be
described in more detail hereinafter, the difference in distance
traveled by the gear 41 (really the motor 15a) and the encoder
wheel 31, as the paddle 34 traverses the sump 33 counter clockwise
from the 9:00 position (see FIG. 2,) to about the 5:00 position, is
a measure of how much toner 35 remains in the sump 33 and therefore
how many pages may yet be preinted by the EP machine or printer 10
before the cartridge 30 is low on toner. This measurement technique
will be explained more fully with reguard to finding the home
position of the encoder wheel 31 and reading the wheel.
[0049] Turning now to FIG. 6 which is a simplified electrical
diagram for the machine 10 illustrating the principal parts of the
electrical thereof, the machine employs two processor
(micro-processor) carrying boards 80 and 90, respectively labeled
"Engine Electronics Card" and "Raster Image Processor Electronics
Card" (hereinafter called EEC and RIP respectively). As is
conventional with processors, they include memory, I/O and other
accounterments associated with small system computers on a board.
The EEC 80 as shown in FIG. 6, controls machine functions,
generally through programs contained in the ROM 80a on the card and
in conjunction with its on-board processor. For example, on the
machine the laser printhead 82; the motor transport assembly 15;
the high voltage power supply 83 and a cover switch 83a which
indicates a change of state to the EEC 80 when the cover is opened:
the Encoder Wheel Sensor 31a which reads the code on the encoder
wheel 31 informing the EEC 80 needed cartridge information and
giving continuing data concerning the toner supply in the sump 33
of the EP cartridge 30; a display 81 which indicates various
machine conditions to the operator under control of the RIP when
the machine is operating but capable of being controlled by the EEC
during manufacturing, the display being useful for displaying
manufacturing test conditions even when the RIP is not installed.
Other functions such as the Erase or quench lamp assembly 84 and
the MPT paper-out functions are illustrated as being controlled by
the EEC 80. Other shared functions, e.g., the Fuser Assembly 86 and
the Low Voltage Power Supply 87 are provided through an
interconnect card 88 (which includes bussing and power lines) which
permits communication between the RIP90 and EEC 80 and other
peripherals. The Interconnect card 88 may be connected to other
peripherals through a communications interface 89 which is
available for connection to a network 91 non-volatile memory 92
(e.g., Hard drive), and of course connection to a host 93, e.g., a
computer such as a personal computer and the like.
[0050] The RIP primarily functions to receive the information to be
printed from the network or host and converts the same to a bit map
and the like for printing. Although the serial part 94 and the
parallel port 95 are illustrated as beinig separable from the RIP
card 90, conventionally they may be positioned on or as part of the
card.
[0051] Prior to discussing via the programming flow chart, the
operation of the machine in accordance with the invention, the
structure of the novel encoder whell 31 should be described. To
this end, and referring now to FIG. 7, the encoder wheel 31 is
preferably disk shaped and comprises a keyed central opening 31b
for receipt by like shaped end 32a of the shaft 32. The wheel
includes several slots or windows therein which are positioned
preferably with respect to a start datum line lableled D0, for
purposes of identification. From a "clock face" view. DO resides at
6:00, along the trailing edge of a start/home window 54 of the
wheel 31. (Note the direction of rotation arrow 34a.) The paddle 34
is schematically shown positioned at top-dead-center (TDC) with
respect to the wheel 31 (and thus the sump 33). The position of the
encoder wheel sensor 31a, although stationary and attached to the
machine, is assumed, for discussion purposes aligned with D0 in the
drawing and positioned substantially as shown schematically in FIG.
1.
[0052] Because the paddle 34 is generally out of contact with the
toner in the sump, from the 3:00 position to the 9:00 position
(counter clockwise rotation as shown by arrow 34a), and the shaft
velocity may be assumed to be fairly uniform when the paddle moves
from at least the 12:00 (TDC) positioned to the 9:00 position,
information concerning the cartridge 30 is preferably encoded on
the wheel between 6:00 and approximately the 9:00 position. To this
end, the wheel 31 is provided with radially extending, equally
spaced apart, slots or windows 0-6, the trailing edges of which are
located with respect to D0 and labled D1-D7 respectively. Each of
the slots 0-6 represents an information or data bit position which
may be selectively covered as by one or more decals 96, in a manner
to be more fully explained hereinafter with reference to FIG. 10.
Suffice at this point that a plurity of apertures 56-59 are located
along an arc with the same radius but adjacent the data slots or
windows 0-6. Note that the spacing between apertures 56 and 57 is
less than the spacing between apertures 58 and 59.
[0053] The coded data represented by combinations of covered,
not-covered slots 0-6 indicate to the EEC 80 necessary information
as to the EP cartridge initial capacity, toner type, qualified or
unqualified as an OEM type cartridge, or such other information
that is either desirable or necessary for correct machine
operation. Adjacent slot 6 is a stop window 55 which has a width
equal to the distance between the trailing edges of adjacent slots
or windows, e.g., D1=(D2-D1, =D3-D2 etc.)=the width of window 55.
Note that the stop window 5 is also spaced from the trailing edge
of slot 6 a distance equal to the stop window width 55. That is,
the distance D8-D7=twice the window 55 width while the window width
of window 55 is greater than the width of the slots 0-6.
[0054] Adjacent slot 0, from approximately the 5:00 to the 6:00
positioned is a start/home window 54. The start/home window 54 is
deliberately made larger than any other window width. Because of
this width difference, it is easier to determine the wheel position
and the start of the data bit presentation to the encoder wheel
sensor 31a. The reason for this will be better understood when
discussing the programming flow charts of FIG. 8A and 8B.
[0055] In order to provide information to the EEC 80 as to the lag
of the encoder wheel 31 relative to the transport motor 15a
position (counted increments), three additional slots or windows
"a", "b" and "c" are provided at D9, D10 and D11 respectively. The
trailing edge of slot "a" (angular distance D9) is 200.degree. from
D0; the trailing edge of slot "b" (angular distance D10) is
215.degree. from D0 and the trailing edge of slot "c" (angular
distance D11) is 230.degree. from D0. From FIG. 7 it may be seen
that when the slot "a" passes the sensor 31a at D0, the paddle 34
will have already passed bottom dead center (6:00 position) by
20.degree. (200.degree.-180.degree. ); window or slot "b" by
35.degree. (215.degree.-180.degree. ). The significance of the
placement of the slots "a", "b" and "c" will be more fully
explained, hereinafter, with respect to FIG. 9.
[0056] Referring now to FIGS. 8A and 8B which shows respectively a
programming and functional flow chart illustrating the code
nesessary for machine start up, and the reading of information
coded on the encoder wheel, including the measurement of toner 35
level in the toner sump 33. At the outset, it is well that it be
understood that there is no reliance on or measurement of the speed
of the machine, as it differs depending upon the operation (i.e.,
resolution: toner type; color etc.) even though a different table
may be required for look up under gross or extreme speed change
conditions. Accordingly, rather than store in the ROM 80a a norm
for each of several speeds to obtain different resolutions to which
the actual could be compared to determine the amount of toner left,
what is read instead is the angular `distance` traversed by the
encoder wheel 31 referenced to the angular distance traveled by the
motor, and then comparing the difference between the two angular
measurements to a norm or based-line to determine the amount of
toner 35 left in the sump 33. By observation, it can been seen that
the distance that the encoder whell travels between start or home
(D0) and "a", "b", "c " is always the same. So what is being
measure is the distance the motor has to travel before slot "a" is
sensed slot "b" is sensed and slot "c" is sensed, and then taking
the difference as being the measured lag. In essence, and perhaps
an easier way for the reader to understand what is being measured,
is that the angular displacement of the paddle 34 is being measured
with respect to the angular displacement of the gear 41 (gear train
40 as part of transport motor assembly 15). As discussed below, the
greatest number (lag number) indicates the paddle position which
gives the highest torque (the most resistance). This number
indicates which look up table in ROM should be employed and gives a
measure of how much toner 35 is left in the sump 33 of the
cartridge 30.
[0057] Referring first to FIG. 8A, after machine 10 start up or the
cover has been operated and later closed, the Rolling Average is
reset, as shown in logic block 60. Simply stated, `n` (e.g., 5 or
6) sample measurements are examined and the average of them is
stored and the code on the encoder wheel 31 of the cartridge 30 is
real, compated to what was there before, and then stored. The
reason for doing this is that if a user replaces an EP cartridge
since the last power on or machine 10 startup, there may be a
different tonery rype, toner level etc. in the new sump.
Accordingly, so as not to rely on the old data, new data is secured
which includes new cartridge data and/or amount of toner 35
remaining in the cartridge 30. Therefore a new `rolling average` is
created in the EEC 80. With regard to host notification, however,
the old data would be reported because the great majority of time
when the machine is started up or the cover is closed once opened,
a new cartridge will not have been installed, and reliance may
usually be placed upon the previous information.
[0058] The next logical step at 61 is to `Find the Home position`
of the encoder wheel 31. In order for either the toner level or
cartridge characteristics algorithms to operate properly, the "home
position" of the wheel 31 must first be found. Necessary, the EEC
80, through sensor 31a must see the start of a window before it
begins determining the home or start position of the wheel since
the engine could be stopped in, for instance, the stop window 55
position and due to backlash in the system, the motor may move
enough distance before the encoder wheel actually moves that the
measured "total window width" could appear to be the start/home
window 54. Below is set forth in pseudo code the portion of the
program for finding the start/home window 54. As previously
discussed, the start/home window 54 is wider than the stop window
55 or for that matter, any other slot or window on the encoder
wheel 31.
1 'Find the home window first 'This loop runs on motor "increments"
HomeFound = False while ( ! HomeFound) If (found the start of a
Window) Then Window Width = 0 While (not at the end of Window)
{increment WindowWidth} If (WindowWidth > MINIMUM_HOME_WIDTH AND
WindowWidth < MAXIMUM_HOME_WIDTH) Then HomeFound = True End if
End While
[0059] In the above algorithm, `HomeFound` is set false and a loop
is run until the window or slot width meets the conditions of
greater than minimum but less than maximum then `HomeFound` will be
set true and the loop is ended. So the algorithm in essence is
articulating: see the window; compare the window with predetermined
minimum and maxumum widths for identification; and then idicate
that the `home window` 54 has been found when those conditions are
met.
[0060] To ensure that the algorithm found home properly, after it
identifies the stop window 55 it checks to ensure that the position
of the stop window 55 is within reason with respect to the
start/home window 54 and of course that the window width is
acceptable. This occurs in logic blocks or steps 62, 63 and 64 in
FIG. 8A. If this condition is not met, then the configuration
information should be taken again. If this check passes, then there
is no need to continue to look at the configuration information
until a cover closed or power on cycle occurs. This guards against
the potential conditions wherein the engine misidentifies the
start/home window 54 and thus mis-characterizes the cartridge
30.
[0061] Prior to discussing the pseudo-code for `Reading the Wheel`,
it may be helpful to recall that a portion of the encoder wheel's
31 revolution is close enough to constant velocity to allow that
section to be used and read almost as a "windowed bar code". With
reference to FIG. 7 that is the section of the wheel 31 from the
trailing edge of the start/home window 54 to the trailing edge of
the stop window 5 including the slots or windows 0-6. This is
preferably in the section of the encoder wheel 31 in which the
paddle 34 is not impinging upon or in the toner 35 in the sump 33.
Passage of this section over the optical sensor 31a creates a
serial bit system which is decoded to gather read-only information
about the cartridge. The information contained in this section may
comprise information that is essential to the operation of the
machine with that particular EP cartridge or "nice to know"
information. The information may be divided for example into tow or
more different classsifications. One may be cartridge `build`
specific i.e., information which indicates cartidge size, toner
capacity, toner type, photo conductor (PC) drum type and is
personalized when the cartridge is built, the other which may allow
for a number of unique "cartridge classes" which may be
personalized before cartridge shipment, depending for example, upon
the OEM destination. The latter classification may, for example
inhibit the use of cartridges from vendors where it is felt that
the cartridge will give inferior print may have some safety concern
or damage the machine in some way. Alternatively, if the machine is
supplied as an OEM unit to a vendor for his own logo, the
cartridges may be coded so that his logo cartridge is that which is
acceptable to the machine. The selective coding by blocking of the
windows may be performed via a stick-on-decal operation which will
be more fully explained with reference to FIG. 10.
[0062] The `Find Home` code determines the start/home window 54 and
measures the distance corresponding to the trailing edge of each
window 0-6 from the trailing edge of the window 54. This
acquisition continues until the engine detects the stop window 55
(which is designed to have a greater circumferential width then the
data windows 0-6 but less than the start/home window 54). Using a
few integer muliplications, the state of each bit in the byte read
is set using the recorded distance of each window 0-6 from the
trailing edge of the home window 54.
[0063] The portion of the program for reading the encoder wheel, in
pseudo-code, is as follows:
2 `Find Home` (see above) 'Gather distances for all of the data
window 'This loop runs on motor "increments" Finished = False
WindowNumber = 0 CumulativeCount = 0 while(!Finished)
CumulativeCount = CumulativeCount + 1 If (the start of a window is
found) Then WindowWidth = 0 While (not at the end of Window)
increment WindowWidth increment CumulativeCount End While If
(WindowWidth > Minimum Stop window Width AND WindowWidth <
Maximum Stop Window Width AND CumulativeCount > Minimum Stop
Position AND CumulativeCount < Maximum Stop Position)Then 'we
must ensure that the stop window is really what we found Finished =
True StopDistanceFromHome = CumulativeCount Else
DistanceFromHome(WindowNumber)=CumulativeCount WindowNumber =
WindowNumber + 1 End If' check for stop window End If'check for
start of window End While 'Now translate measurements into physical
bits Data Value = 0 'First divide the number of samples taken by 9
BitDistance = StopDistanceFromHome/9 For 1 = 0 To WindowNumber - 1
BitNumber = DistanceFromHome(I)/BitDistance 'What is being
determined is the bit number corresponding to the 'measurement by
rounding up DistanceFromHome(I)/BitDistance. If
((DistanceFromHome(I) - (BitDistance * BitNumber)) * 2 >
BitDistance) Then BitNumber = BitNumber + 1 End If DataValue =
DataValue + 1 (SHIFTLEFT) BitNumber - 1 Next' Window number
DataValue = -DataValue ' invert result since windows arc logic
0's
[0064] The program depicted above in pseudo code for reading the
wheel is quite straight forward. Thus in logic step 63, (FIG. 8A)
where the motor increments are recorded for each data bit, and stop
bit trailing edge, as was discussed with regard to FIG. 7 that the
distances D1-D7 between the trailing edges of windows or slots 0
through 6, are equally spaced. (i.e., D7-D6=some constant "K",
D5-D4=constant "K" etc.) The trailing edge of the stop window 55 is
also a distance of twice "K" from the trailing edge of slot 6.
While the distance from the trailing edge of stop window 5 to its
leading edge (i.e., the window 55 width) is equal to one `bit`
distance or "K" from the leading edge, this width may be any
convenient distance as long as its width is >than the width of
the slots 0-6 and <the width of the start/home window 54. Thus
the line of pseudo code above `Fisrt divide the number of samples
taken by 9` (from the trailing edge of the start/home window of
slot 54) means that there are 7 bits from D1 throught D7, plus two
more through D8, and therefore `/9` gives the spacing "K" between
the windows (trailing edge of the start/home window or slot 54 to
the trailing edge of the stop window 55) which may be compared to
what this distance is supposed to be, and in that manner insure
that the bit windows 0-6 and stop window 55 have been found. If the
stop window 5 is not identified correctly by the technique just
described, then a branch from logic step 64 to logic step 61 will
once again initiate the code for finding the home position, as in
block 61 and described above.
[0065] In logic block or step 65, the next logical step in the
program is to go to the Data Encoding Algorithm portion of the
program. In the pseudo code set forth above, this starts with the
REM statement "Now translate measurement into physical bits". Now,
assume that when coded, the encoder wheel 31 has several of the
bits0-6 covered, as by a decal so that light will not pass
therethrough. Suppose all data bit slot but 6 and the stop window
55 are covered. A reading of distance D8/9 will give the spacing
between the data slots or windows 0-6. Therefore, the distance to
slot D7, i.e., the trailing edge of slot 6, will be 7 times "K"
(bit spacing) and therefore will indicate that is a bit 7 that is
emissive and that the bit representation is 1000000, or if the
logic is inverted, 0111111. Notice that the number found is rounded
up or down, as the case may be dependent upon such factors as
paddle mass, rotational speed etc. In certain instances, this may
mean rounding up with a reading above0.2 and rounding down with a
reading below 0.2. For example, 6.3 would be rounded to 7, while
7.15 would be rounded to a 7.
[0066] In logic step 66 the question is asked: "Does the machine
stop during paddle rotation?" If it does, logic step 67 is
initiated. The reason for this is that if the paddle is stopped,
especially when in the portion of the sump 33 containing a quantity
of toner 35 in order to release the torsion on the spring 44 the
motor 15a is backed up several increments. This will allow removal,
and/or replacement, if desired, of the EP cartridge 30. This logic
steps allows for decrementing the number of steps "backed up" from
the incremental count of motor increments which was started in
logic block 62.
[0067] Turning now to FIG. 8B, as the encoder wheel 31 rotates, the
paddle 34 enters the toner 35 in the sump 33. As described above
relative to logic step 62, the motor increments are counted. The
motor increments are then recorded as S200, S215 and S230, in logic
step 68a, 68b and 68c at the trailing edges of slots "a", "b", and
"c" respectively of the wheel 31. These numbers, S200, S215 and
S230 are subtracted from the baseline of what the numbers would be
absent toner 35 in the sump 33, (or any other selected norm) which
is then directly indicative of the lag due to resistance of the
toner in the sump with the paddle 34 in three different positions
in the sump. This is shown in logic steps 69a-69c respectively. As
has previously been stated there is a correlation between load
torque on the toner paddle 34 and the amount of toner 35 remaining
in the toner supply reservoir or sump 33. FIG. 9 illustrates this
relationship. In FIG. 9 torque is set in inch-ounces on the
ordinate and degrees of rotation of the paddle 34 on the
abscissa.
[0068] Referring briefly to FIG. 9 serveral characteristics of this
data stand out as indicating the amount of toner remaining. The
first one is the peak magnitude of the torque. For example, with 30
grams of toner 35 remaining in the sump 33, the torque is close to
2 inch-ounces while at 150 grams the torque approximates 4
inches-ounces and at 270 grams the torque approximates 8
inch-ounces. The second characteristic is that the location of the
peak of the torque curve does not move very much as the amount of
toner changes. This suggests that measuring the torque near the
location where the peak should occur could provide a measure of
remaining toner. That is why, as shown in FIG. 7 the trailing edge
of slot "a" (distance D9) is 200.degree. from D0; the trailing edge
of slot "b" (distance D10) is 215.degree. from D0 and the trailing
edge slot "c" (distance D11) is 230.degree. from D0. Another
obvious indicator is the location of the onset of the torque load.
Yet a third indicator is the area under the torque curves.
[0069] Another way of looking at this process is that while the
angular distance mesurements of D9, D10 and D11 are known, the
number of increments the motor has to turn in order that the
resistance is overcome as stored in the torsion spring 44, is the
difference in distance the motor has to travel (rotational
increments) to obtain a reading at window "a" then "b" and then
"c". The delay is then compared as at logic step 70 and 71, and the
largest delay is summed as at logic steps 72, 73 or 74 to the
rolling average sum. Thereafter a new average calculation is made
from the rolling average sum. This is shown in logic step 75. As
illustrated in logic block 76 the toner 35 level in the sump 33 may
then be determined from a look up table precalculated and stored in
the ROM 80a associated with EEC 80 in accordance with the new
rolling average.
[0070] In logic block 77, the oldest data point is subtracted from
the rolling average sum and then the rolling average sum is
reported for use back to logic block 61 (Find Home position). If
the toner level changed from the last measurement, as in compare
logic block 78, this condition may be reported to the local RIP
processor 90 and/or the host machine, e.g., a personal computer as
indicated in logic block 79.
[0071] Coding of the encoder wheel 31 is accomplished as briefly
referred to above by covering selected ones of slots 0-6 with a
decal. For customization for an OEM vendee and in order to recue
inventory and in accordance with another feature of the invention,
the problem of quickly and accurately applying such a decal to the
correct area of the wheel 31, even under circumstances of limited
space is provided. Due to the close spacing of the slots 0-6 in the
encoder wheel 31, a pre-cut prefereably adhesive backed decal 96 is
employed to selectively cover pre-selected slots depending on how
the decal is cut or stamped. Very accurate positioning of the decal
96 is achieved by use of alignment pins in conjunction with an
alignment tool 100. Because another decal can be placed on another
region of the wheel the spacing of the alignment holes 56-59 on the
encoder wheel 31 is different in each region.
[0072] To this end, as previously discussed, there are two pairs of
apertures in the encoder wheel or disk, adjacent the slots, the
apertures of one of the pairs 58, 59 being spaced apart a greater
distance than the apertures 56-57 of the other pairs. Referring now
to FIG. 10a decal 96 is sized to fit over at least one of the slots
0-2 or 3-6 to cover the same. As illustrated the decal 96 has
spaced apart apertures therein corresponding to one of the pairs of
apertures, i.e., 58, 59 or 56, 57. A tool 100 has a pair of pins
97, 98 projecting therefrom and corresponding to the spacing of one
of the pairs of apertures, whereby whe the apertures in the decal
are mated with the projecting pins of the tool, the projecting pins
of the tool may be mated with one pair of apertures in the encoder
wheel or disk to thereby accurately position the decal over the
selected slot in the disk. The decal 96 is installed on the tool
with the adhesive side facing away from the tool. The tool 100 is
then pushed until the decal 96 makes firm contact with the surface
of the wheel.
[0073] If the pins 97 and 98 are spaced equal to the spacing
between apertures 56 and 57 the decal cannot, once on the tool 100
be placed covering slots associated with the incorrect apertures 58
and 59. The opposite condition is also true. Accordingly, two such
tools 100 with different pin 97, 98 spacing may be provided to
insure proper placement of the correct decal for the proper slot
coverage. Alternatively, a single tool 100 with an extra hole for
receipt of a transferred pin to provide the correct spacing may be
provided.
[0074] This method of selective bit blocking is preferred because
the process is done at the end of the manufacturing line where less
than all of the wheel 31 may be exposed. Use of this tool 100 with
differing spaced apart pins allows the operator to get to the
encoder wheel 31 easily and prevents misplacement of the decal.
[0075] FIGS. 11A-11E are directed to refinements in th emethod of
the invention depicted in FIGS. 8A and 8B. Such refinements
include, for example, improvements in the code to further reduce
the incidence of mistakes in location of the stop window 5 (or stop
bit). As shown in FIG. 11A in comparison to FIG. 8A additional
steps 160, 161, and 162, are present wherein further logic
associated with step 161 is depicted in FIG. 11C and further logic
associated with step 162 is depicted in FIG. 11D. Furthermore,
shown in FIG. 11B in comparsion to FIG. 8B and continuing into FIG.
11E is a presently more preferred manner of determining with
somewhat greater accuracy, the amount of toner remaining in the
sump (toner level) regardless of the speed of rotation of the
paddle 34 and associated encoded plate, or encoder wheel 31. In the
following discussion, functional steps depicted in FIGS. 11A-11E
which are common or substantially similar, to those functional
steps of FIGS. 8A and 8B will bear the same element numerals, and
the detail of those common steps will not be repeated below.
[0076] As shown in FIGS. 8A and 8B, the steps associated with
reading of the preselected cartridge characteristics and the steps
associated with dtermining the toner level in sump 33 are perfromed
in parallel. With respect to FIG. 11A and 11B, however, as shown at
step 160, such parallel processing continues until the decoding of
the preselected cartridge characteristics is successful and
thereafter, only the steps associated with determining the toner
level in sump 33 (steps 66 and 67 of FIG. 11A, and the steps of
FIGS. 11B and 11E) are performed. Such preselected cartridge
characteristic may include, for example, initial cartridge capacity
toner type, PC drum type, qualified or unqualified as an OEM type
cartridge, etc. One skilled in the art will recognize that such
parallel processing may be achieved in a variety of ways such as
for example, by interleaving the program steps of the parallel
paths within a single processor or by using a seperate processor
for each path.
[0077] Referring no to 11A, after machine 10 is started up, or
after the printer cover has been opened and later closed, the
variable indentified as a "Rolling Average" is reset at step 60.
The resetting of the Rolling Average occurs prior to executing the
stpes associated with reading the coding representing preselected
cartridge characteristic from wheel 31, i.e., steps 61, 62, 160,
63, 161, 64, 65 and 162, and prior to determining the amount of
toner remaining in sump 33 of cartridge 30 beginning at step 66,
and continuing into FIGS. 11B and 11E.
[0078] In order for either the preselected cartridge
characteristics steps or the toner level determining steps to
properly, the "home position" of the wheel 31 must first be found
as at step 61. The previous discussion concerning the encoder wheel
31 and the reading thereof to determine the home position of wheel
31 is equally applicable to the refinements depicted in FIGS.
11A-11E. Morever, the pseudo code for "Reading the Wheel",
disscussed above is equally applicable for reading the encoder
wheel, execept that the portion of the code relating to the window
width may be simplified, as follow:
3 If (WindowWidth > Minimum Stop window Width AND
CumulativeCount < Maximum Stop Position)Then 'we must ensure
that the stop window is really what we found Finished = True
[0079] At step 62, the counting of increments of shaft rotation of
the drive motor begins at the position associated with the trailing
edge of start/home window 54. Therefore, at step 160 a check is
made as to whether the coding representing preselected cartridge
characteristics was successfully decoded. If this preselected
cartridge characteristics coding was not successfully decoded, then
the paraellel progressing of the preselected cartridge
characteristics and the determination of toner level continues; if
so, however, such parallel precessesing ends and only those steps
associated with determining the toner level in cartridge 30 are
performed.
[0080] During the decoding of the preselected cartridge
characterics of wheel 31, at step 63 the number of motor increments
from the trailing edge of start window 54 to each of the data bit
windows 0-6 and stop window 55, respectively, are recorded.
Thereafter the steps of FIG. 11C are performed.
[0081] Turning now to FIG. 11C, a check is made at step 165 to
determine if more than 7 bits have been seen between the home
window 54 and the stop window or bit 55. If yes, then step 61 is
re-executed and the home position is once again found. This test to
detect and determine the presence or absence of an excess of a
finite number of slots or bits on the encoder wheel 31 is preferred
because as the wheel rotates, causing the sensor to detect either a
transition from open to closed state or vice-versa, bounce may
occur. If the bounce duration is very small it will be rejected as
a window (slot), otherwise it may pass and be considered a valid
window. In such a seenario certain cartridges may appear to have
more bit windows than physically possible. After each bit window is
detected, the number of bit window detected from the previous home
detection is compared is to a maximum value and if too many windows
have been detected, then the coded returns to the steps for finding
the home state via path 194.
[0082] Another condition that can occur which makes a further check
desirable is when the sensor signal transition from one state to
the other and immediately back to the original state resulting in
the indication of a detection of an additional, or redundant
window. A test for such a condition is performed at step 166. As
shown in FIG. 7 and as has already been discussed bit or slot
distances on the wheel known and mapped. The identified of what
appears to be two bits or slots in the same region on wheel 31 is
identified as an error in reading the preselected cartridge
characterics for that particular revolution of wheel 31 and results
in a return to re-execute of step 61 if FIG. 11A via path 194.
[0083] Referring again to FIG. 11C, step 167 is performed so as to
assume that the code bits 0-6 are not mistake for the stop bits.
Thus, at step 167 the number of motor increments counted is
compared to a predefined maxiumum number of such increments
associated with the distance between the trailing edge of home
window 54 and the trailing edge of stop window 55. If the number of
motor increments is not less than the predefined maximum number
then via return loop 194, step 61 of FIG. 11A is re-entered and
this loop continues until a correct reading is acheived, or until
an error code indicates a fatal error to the machine operator. If
the number of motor increments is equal to or greater than the
predetermined maximum then step 168 is executed, wherein it is
determine whether the measured window or slot width is greater than
the minimum stop width. If not, then step 63 is re-entered via path
184. In the event that the stop window 55 width is greater than the
slot window width, then a check is made at step 169 to determine
whether the duration (in motor increments) of closure of the
reader/sensor is a sufficient number of increments to indicate a
reading of stop window 55 versus the last bit read for example,
slot 6. If slot 6 is covered, the distance or closure reading will
be even longer. In the event that closure of the sensor has not
occured for a sufficient period of time then loop 184 line is again
entered and logic step 63 is once again initiated. In the event
that the closure of the sensor has occured for a sufficient period
of time, the step 65 of FIG. 11A is executed.
[0084] To further insure accurate reading of the encoder wheel 31
spring 44 is preloaded to a known torque valve. Preferably, this
preload value is a small as possible to allow for accurate reading
of low levels of toner in sump 33. The preload may be acheived by
for example, providing an adjustable tab stop in place of either or
both tabs 51 and 52 of FIG. 4. Such an adjustable tab stop can be,
for example, a rotatable eccentric stop.
[0085] Step 65 is directed to the actual decoding of the
preselected cartridge characterics coding of encoder wheel 31, the
details of which are more fully described with respect the steps of
FIG. 11D, which constitute step 162 of FIG. 11A. In the pseudo code
set forth above this starts with REM statement "Now translate
measurements into physical bits" and the discussion concerning
distances and rounding applies. In table 170 of FIG. 11D which may
be referred to as a `loop table`, logic is utilized in a loop for
each reading D1-D7 of the code wheel 31 (see FIG. 7), and takes
into account the rounding discussed heretofore. Note that the "code
registered" is the code which would be read at each of the
respective bit positions corresponding to windows or slots 0-6,
wherein a "1" represents an open slot at the respective bit
position. The final code is a result of ANDing each column of bits
in the seven "code registered" entries. For example, if none of the
slots or windows is covered, then the final code reading will be
1111111; if slot 0 (FIG. 7) is covered, then the reading will be
1111110; and if slot 2 is also covered, the reading will be
1111010. Of course, such binary representations may be inverted
such that a "1" represents a covered slot, rather that a "0".
[0086] The code read from the loop table 170 is then interpreted by
a look up table at logic step 171 and the interpreted code is then
sent to the EEC 80 in logic step 172. By a logical comparsion, if
the code is the same as that which is stored in NVRAM in EEC 80 as
indicated in step 173 no further reading of the code is necessary
and the decoding of the preselected cartridge characteristics
coding of encoded plate, or wheel 31 is ended until the next
occurrance of machine start-up or machine cover cycling. To
decrease decode time, afte the same code has been read
consecutively twice, this code is stored in the NVRAM (logic step
175) for furture comparisions and the steps for decoding the coding
representing the preselected cartridge characteristics information
is ended. In the event that the code has not been read twice a
counter is set with a "1", and as shown in logic step 174, the path
via line 194 (FIG. 11A is entered for re-reading the code beginning
at step 61 of FIG. 11A.
[0087] Once the decoding of the preselected cartridge
characteristic coding is complete the logic at step 160 then
ignores further preselected cartridge characteristic code reading
of wheel 31 and the method turns to solely reading the delay bits
"a", "b", and "c" as discussed hereinafter relative to FIG. 11B, in
determining the amount, or level, of toner sump 33 of cartridge 30.
In the presently preferred configuration of the encoder wheel 31,
the trailing edge of slot "a", (angular distane D9) is 182.degree.
from D0; the trailing edge of slot "b" (angular distance D10) is
197.degree. from D0 and the trailing edge of slot "c" (angular
distance D11) is 212.degree. from D0.
[0088] Referring again to FIG. 11A, the explanation for the logic
steps 66 and 67 is the same as set forth heretofore and will not be
repeated here. However, in further explaination, when reverse
motion is detected a counter counts the number of back increments
or steps and that same number is applied or substrated as the
motion is reversed to forward so that the count is resumed when the
wheel begins its forward motion again. For example, in a single
page print job the encoder wheel will stop before a full revolution
is complete. The machine will run the transport motor in reverse
for a short distance after each stop in order to relieve pressure
in the gear train. As set forth above, this permits, if desired,
cartridge removal and/or replacement. Without correction, this
could induce a considerable error in measurement of toner level. To
account for this, the amount of excess motor pulses counted during
the backup and restart are filtered out of the delay counts
measured for toner level sensing.
[0089] Turning now to FIG. 11B, as has been explained heretofore
with reference to FIG. 8B, as encoder wheel 31 rotates, paddle 34
enters toner 35 in sump 33. As set forth heretofore with reference
to FIG. 8B, the angular distances of D9, D10 and D11 are known and
the number of no-load motor increments required to reach D9, D10
and D11 is known. The motor, via torsion spring 44, rotates paddle
34 and encoder wheel 31. As paddle 34 moves through toner 35
however, a paddle-to-toner resistance is incurred, which results in
a torsioning of torsion spring 44, since the motor is essentially
rotating at a constant rate. Thus, the actual number of motor
increments required to reach each of the respective locations D9,
D10, and D11 is greater during a load condition when paddle 34
engages an amount of toner than when a lesser amount or no toner is
engaged. This difference in the distance the motor has to travel
(rotational increments) to obtain a reading at window "a", then "b"
and then "c" corresponds to a level of toner in sump 33.
[0090] As described above relative to logic step 62 (FIG. 11A), the
motor increments are counted. The motor increments are then
recorded as S200, S215 and S230 in steps 68a, 68b and 68c (FIG.
11B) at the trailing edges of slots "a", "b", and "c", respectively
of the wheel 31 and substracted from the baseline of what the
number would be absent toner 35 in the sump 33 at steps 69a, 69b,
and 69c, respectively. These numbers are directly indicative of the
lag due to resistance of the toner sump 33, with the paddle 34 in
three different positions (a, b, and c) in the sump. Thus, this lag
or delay is determined and shownin in steps 69a-69c, respectively.
As has been previously stated, there is a correlation between load
torque on the toner panel 34 and the amount of toner 35 remaining
in the toner supply reservoir or sump 33. (See FIG. 9 and the
discussion relating thereto.)
[0091] At steps 70 and 71, the respective baseline normalized
delays are compared, and one of the three delays is slected for use
in determining the toner level of cartridge 30 at the then current
printer operating speed in pages per minute (ppm) at steps 72',
73', or 74'. As shown in FIG. 11B at step 70, the normalized delay
@200 will be used to calculate the toner level unless its value is
not greater than that of normalized delay @215. If the normalized
delay @200 is less than or equal to normalized delay @215, then at
step 71 it is determined whether normalized delay @215 is greater
than normalized delay @230. If so, then the normalized delay @215
is used, and if not, then normalized delay @230 is used in the
toner level detemination. Alternatively, a maximum normalized delay
figure can be used in the toner level calculation.
[0092] Preferably, the normalized delay selected in the toner level
detemination is sent to an equation for calculating the toner level
mass (in grams of toner) at a particular machine speed in pages per
minute (ppm). The equation to determine, at different ppm printing
speeds, the mass in grams of toner remaining in the cartridge is
the linear equation: y=mx+b where:
[0093] m=slope measurement in grams/pulse (or increments);
[0094] b=y axis intercept, or offset, where x=0 grams; and
[0095] x=average number of pulses, or increments.
[0096] The values for variables m and b are essentially constants
with respect to various printing speeds. These values may be
determine empirically, or calculated or determined base upon
assumptions. For example, the following table represents the values
for variables m and b assuming 10.80 motor pulses per degree of
encoder wheel rotation.
4 8 ppm 12 ppm 18 ppm 24 ppm m b m B m b m b .18 55 .19 52 .21 48
.23 45
[0097] Using the above table, for example, for an 8 ppm operating
speed, the equation above becomes: y=0.18x+55. Accordingly, if
x=100, then it is determined that 73 grams of toner remain in sump
33.
[0098] It has been found that with a single speed machine, i.e.,
one that runs at a single speed of rotation of the drum a rolling
average of the delays measured permits calculating toner level, in
grams, from the outcome of that average. Under those limited
circumstances, the toner level in the sump 33 may then be
determined from a look up table precalculated and stored in the ROM
80a associated with teh EEC 80 in accordance with the new rolling
average. Many printers, however, are capable of multiple
resolutions which may require different motor speeds, e.g., 300 dpi
(dots per inch), 600 dpi, 1200 dpi, etc. which means that this
manner of determining the amount of toner left in the cartridge
would be accurate for only one speed. Moreover, delay is a function
of both paddle velocity and toner level. In the instance where a
printing job requires alternate printing at 600 and 1200 dpi the
machine runs at a different speed for each of these resolutions,
and the toner level measurement is difficult to determine by the
rolling average method because the rolling average contains delays
measured at all of those speeds. To account for this, the rolling
average is taken of a velocity independent parameter, i.e., grams.
The equation given above converts the measurements of maximum
delays immediately to grams as in logic steps 76'. The rolling
average is then taken of grams, a speed independent parameter, and
therefore velocity changes will not affect the toner level
measurement. This is shown in logic step 75'.
[0099] Following step 75', the steps of FIG. 11E are performed in
preparing to report a toner level or toner low indication, for
example, to the EP machine and/or an attached computer. At step
176, the first value of the rolling average from logic step 75' is
stored. Subsequent values are stored as AVG2 for comparsion to
MINAVG. In decision step 177, the value for the rolling average
(AVG2) is compared to the previous value MINAVG. If AVG2 is not
less than MINAVG, (which would be the normal situation), AVG2 is
cleared in logic step 179 and AVG2 is reset with the next value of
the rolling average. If the comparsion is affirmative, then a
further test is performed at step 178 to determine whether the
difference between the two readings is logical. If the difference
is less than 30 (grams) then the reading is considered logical. If,
on the other hand, the difference is greater than or equal to 30
then the reading discarded as being noise and once again logic
block 179 is entered for clearing AVG2 and resetting it with the
next value of the rolling average. If the comparsion value is less
than 30 at step 178, the MINAVG is set equal to AVG2 at step 180
and sent to steps 179 and 181 in parallel. Depending upon the
machine, it has been discovered that it may be desirable to add a
scale factor to MINAVG, such as for example, a scale factor (SF) of
3 grams, as is shown at step 181.
[0100] The amount of toner held in the sump 33 of a cartridge 30
can vary. Standard toner quantity, measured in grams for a full
cartridge, is approximately 400 grams. A user would prefer to know
how much is left for use in the machine, e.g., is the sump 33 is
half full. 3/4full, or 1/8full, and this is achieved at step 182.
The result of step 181, i.e. MINAVG+3 grams is looked up in the ROM
80a of the EEC card 80 (see FIG. 6). Moreover, as shown in logic
step 182, if the toner level increases (as it occasionally does due
to noise and unless the cartridge has been replaced since the last
measurement), this reading is ignored and the previous toner level
is posted as the current level. At step 79', the ROM output returns
a sump level to the local machine processor for a direct reading on
a printer display, or it sends the reading to the host
computer.
[0101] Thereafter, the process returns to step 77' of FIG. 11B, in
which the oldest delay value from the five held in generating the
rolling average is removed. At step 78', the process then delays X
steps or increments, after the first toner level slot before
searching for the "home position", i.e., before returning to step
61 of FIG. 11A. The number of steps X, is chosen to ensure that the
third toner level slot has passed the sensor. Thereafter, steps 62,
160, 66, of FIG. 11A are completed, and the steps of FIGS. 11B and
11E for determining the toner level in sump 33 of cartridge 30 are
repeated.
[0102] One skilled in the art will recognize that an encoder plate,
such as encoder wheel 31, may be fabricated, for example, by
forming slots, or openings, in a material. Such a material is
preferably disk-shaped, and may, for example, be made of plastic or
metal. Although the disk-shaped design is preferred, other shapes
may be used without departing from the spirit of the invention.
[0103] Also, one skilled in the art will recognize that the windows
or slots may be free of any material, or alternatively, filled with
a transparent material. In addition, it is contemplated that the
encoder 31 could be fabricated, for example, from a transparent
material having a coating deposited thereon which defines the
coding, such as for example, by defining the edges of each window,
and in which the coating does not effectively transfer light
impinging on its surface.
[0104] FIGS. 12-16 show further illustrative embodiments of an
encoded wheel corresponding generally to encoder wheel 31 depicted
in FIGS. 1-3, and 7. For example, and referring first to FIG. 12,
the encoder wheel 31 may be replaced by an indentically slotted
wheel 131 composed of a ferromagnetic material. The reader/sensor
131a, in this instance, may include an alternative energy source
such as a magnet 132 and the receptor or receiver may comprise a
magnetic field sensor, such as a Hall effect device, 133 in place
of the optical encoder wheel reader/sensor 31a. In operation, the
ferromagnetic material of the encoder wheel 131 blocks the magnetic
flux emanating from the permanent magnet 132 execpt where there are
slots 135 in the wheel 131. Either the Hall effect device 133 or
the magnet 132 may be attached to one of or both the printer 10 or
cartridge 30.
[0105] In another example, and referring now to FIGS. 13 and 14, an
encoder wheel 231 may be employed in association with another
reader/sensor 231a. In this embodiment, in lieu of slots or windows
in the wheel, such as in encoder wheels 31 and 131, such slots or
windows are replaced with reflective material 235. In this scheme,
the encoder wheel reader/sensor 231a includes a light source 232
and light sensor or receiver 233 which is activated as the encoder
wheel rotates and the light from the light source is reflective
from the reflective material 235. In comparing the windows or slots
of the encoder wheel 31 and the reflective material 235 of wheel
231, it should be noted that the Start/Home window 54 in FIG. 7
corresponds to the Start/Home window (reflective material) 154 in
FIGS. 13 and 14, while the information slots 0 and 1 of the encoder
wheel 31 in FIG. 7, correspond to the reflective material 235 at
0'and 1'of FIG. 14. Preferably, the wheel 231 should be made of a
non-reflective material to avoid scattered or erroneous readings by
the optical reader 233. An advantage of this type of structure is
that the reader/sensor 231a need be only on one side of the encoder
wheel, simplifying machine and toner cartridge design.
[0106] The design of an encoder wheel 31 in FIGS. 15 and 16 may be
similar employing a cam follower acturated reader/sensor 331a. In
these embodiments the encoder wheel 331 includes a
circumferentially extending cam surface 340 on the periphery of the
encoder wheel, wherein the periphery acts as cam lobes 341 with
appropriate cam recesses or depression 342. In comparing the
windows or slots of the encoder wheel 31 and the cam recesses or
depressions 342, it should be noted that the Start/Home window 54
in FIG. 7 corresponds to the Start/Home recess 354 in FIGS. 15 and
16, while the information slots 0 and 1 of the encoder wheel 31 in
FIG. 7, correspond to the cam recesses 342 at "0" and "1" of FIGS.
15 and 16.
[0107] The cam followers 360 and 370 of FIGS. 15 and 16,
respectively, may take multiple forms each cooperating with a
reader/sensor 331a. The reader/sensor may take many forms, for
example a micro-switch which signals, upon actuation, a change of
state; or it may be similar to the reader/sensor 31a or 131a,
except that the cam followed act to interrupt the energy source and
receptor or receiver associated with their own reader/sensor
331a.
[0108] In the embodiment of FIG. 15, the cam follower 360 is formed
as a bar or arm 361 pivoted on a shaft 362, which in turn is
attached, for example, to an appropriate portion of the cartridge
30. Thus, arm 361 acts in pressing engagement with the cam surface
341 due to the action of biasing spring 365. As shown, the biasing
extension spring 365 is connected to one end 363 of the bar or arm
361 and anchored at its other end, preferably, to cartridge 30. The
cam engaging terminal end of the arm or bar may include a roller
366 to reduce sliding friction. The opposite or energy interrupter
end 364 of the bar or arm 361 is appropriately located for
reciprocation about the pivot 362.
[0109] In the embodiment of FIG. 16, the cam follower 370 takes the
form of a reciprocating bar 371 having a centurally located, cam
follower throw limiter slot 372, with locating and guide pins 373
and 374 therein for permitting reciprocation (as per the arrow 379)
of the bar 371. As shown one terminal end 375 of the bar 371, may
include a roller 376 for pressing engagement against the cam
surface 341. To ensure proper following of the follower 370 a
biasing extension spring 377 biases the roller 376 of the bar 371
against the rotating cam surface. As in the embodiment of FIG. 15,
the follower bar 371 includes an engery interrupter portion 378 for
reciprocation into and out of the path between the energy source
and receptor of the reader/sensor 331a.
[0110] Thus, the present invention provides a simple yet effective
method and apparatus for transmitting to a host computer or machine
of a type employing toner information concerning the
characteristics of an EP cartridge. Such information can include
continuing data relating to the amount of toner left in the
cartridge during machine operation and/or preselected cartridge
characteristic information. Still further, the present invention
provides a simplified but effective method and means for changing
the initial information concerning the cartridge which means and
method is accurate enough and simple enought to allow for either in
field alterations or end of manufacturing coding of the EP
cartridge.
[0111] Although the invention has been described with respect to
preferred embodiments, those skilled in the art will recognize that
changes may be made in form and in detail without departing from
the spirit and scope of the following claims.
* * * * *