Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-07-31
2004-01-27
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S023000, C347S029000
Reexamination Certificate
active
06682164
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to inkjet printers. More specifically, the present invention pertains to adapting service operations performed on a printhead of an inkjet printer based upon the calculated age of a service station.
BACKGROUND OF THE INVENTION
In
FIG. 1
, there is schematically illustrated part of a known printer device (e.g., a large format printing device) having an array of printheads
100
in a parallel row. More specifically,
FIG. 1
illustrates six printheads
102
-
112
. Each of the printheads
102
-
112
includes a plurality of printer nozzles (not shown) for firing ink
114
,
116
onto a print medium
120
. Although
FIG. 1
depicts the printer device as having six printheads
102
-
112
, printer devices have been known to possess any number of printheads, e.g., two, four, or more.
The printheads
102
-
112
are typically constrained to move in a direction
170
with respect to the print medium
120
, e.g., paper. In addition, the print medium
120
is also constrained to move in a further direction
160
. During a normal print operation, the printheads
102
-
112
are moved into a first position with respect to the print medium
120
and a plurality of ink droplets
114
,
116
are fired from the same plurality of printer nozzles contained within each of the printheads
102
-
112
. After completion of a print operation, the printheads
102
-
112
are moved in a direction
170
toward a second position and another print operation is performed. In a like manner, the printheads
102
-
112
are repeatedly moved in a direction
170
across the print medium
120
and a print operation is performed after each such movement of the printheads
102
-
112
. When the printheads
102
-
112
reach an edge of the print medium
120
, the print medium is typically moved a short distance in a direction
160
, parallel to a main length of the print medium
120
, and another print operation is performed. The printheads
102
-
112
are then moved in a direction
170
back across the print medium
120
and yet another print operation is performed. In this manner, a complete printed page may be produced.
A more detailed description of the printer device illustrated in
FIG. 1
may found in commonly assigned application Ser. No. 09/502,667 filed on Feb. 11, 2000, by Xavier Bruch et al., the disclosure of which is hereby incorporated by reference in its entirety.
In order to maintain the quality of the printed output of the printer device, it is generally known to maintain the nozzles in substantially proper operating condition. In this respect, a service station
140
is typically provided along a travel path of the printheads
102
-
112
. The service station
140
is typically configured to maintain the health of the printheads
102
-
112
by performing servicing operations on the printheads, e.g., a means for wiping, collecting spit ink, capping the nozzles, etc. The service station
140
typically includes a plurality of service station units
142
-
152
for performing servicing operations on the each of the printheads
102
-
112
. Generally speaking, a respective service station unit
142
-
152
is provided for each of the printheads
102
-
112
. The service station units
142
-
152
are typically housed within a service station frame
154
.
A servicing protocol is typically implemented to control the times and manner in which the printheads
102
-
112
are serviced. For example, in one respect, if it is detected that certain of the nozzles of the printheads
102
-
112
have not fired any ink drops for a certain period of time, the printheads are moved to a position over the service station
140
and caused to fire a normally set number of ink drops to thereby clean out the nozzles. In addition, a wiping mechanism positioned in the service station
140
may be caused to wipe excess ink off the nozzles to thereby increase the probability of their proper functionality. In another respect, the protocol may cause the printheads
102
-
112
to spit a set number of ink drops into the service station after each printing pass in an effort to substantially prevent ink from drying within the nozzles. The servicing protocol typically sets the number of times as well as the frequency of servicing operations based upon a set of normal values which are themselves typically set by the printhead or service station manufacturer. In addition, the normal values of the servicing protocol may vary according to the set printmodes.
The above-described servicing process is generally known as an open loop servicing technique. That is, the servicing protocol that determines when to service the printheads
102
-
112
as well as the degree of servicing to be applied, takes into consideration certain variables, e.g., time uncapped, drops fired during last printing pass, time in cap, etc. However, these types of servicing protocols typically apply a relatively heavy treatment to greater ensure proper printhead performance regardless of the age of the printheads
102
-
112
. One problem associated with the open loop servicing technique is that ink may be wasted by virtue of spitting more ink drops than is necessary, oftentimes resulting in faster aging of the printheads as well as the service station.
Printer devices have also been known to include a drop detector module
130
operable to detect whether the nozzles of the printheads
102
-
112
are properly firing ink. In these types of printer devices, servicing operations on the printheads
102
-
112
may be triggered by detected errors, e.g., clogged nozzles, and a user's expectations, e.g., desired print quality. It is generally known to position the printheads
102
-
112
over the service station
140
and spit a certain number of ink drops to clean out the ink in the nozzles. This servicing process is generally known as a closed loop servicing technique. That is, servicing on the printheads
102
-
112
may occur based upon a closed loop servicing protocol under normal operating conditions, with extra, possibly lighter, servicing operations being performed based upon detected errors, e.g., clogged nozzles. In this regard, the closed loop servicing technique has certain advantages over the open loop servicing technique (e.g., does not waste a relatively large amount of ink, extends the life of the printheads and service station, etc.). However, printer devices that implement the closed loop servicing technique are relatively more expensive and complicated and thus may be unsuitable for certain types of printers (e.g., less expensive printer models).
The age of the service station
140
typically has an impact on the effectiveness of the servicing operation as well as its efficiency. That is, relatively new (or younger) service stations generally perform servicing operations relatively more effectively and efficiently than relatively older service stations. In this respect, older service stations are typically less capable of performing servicing operations in a substantially adequate manner than newer service stations, within the confines of an open loop servicing algorithm. The performance of service stations typically tend to deteriorate with time by virtue of a plurality of factors, e.g., aerosol, ink, wear, dust, etc. Known open loop servicing techniques are generally ill-equipped to compensate for the aging of the service stations. One result of failing to compensate for the aging of the service stations is that when the same level of servicing is performed by an aged service station, the level of servicing may be insufficient to maintain the printheads in relatively proper operating condition, or may otherwise result in wasted ink and unnecessary stress applied on the printheads.
SUMMARY OF THE INVENTION
According to one aspect, the present invention pertains to a method for adapting a service operation of a service station. In the method, a normal service operation is determined and an event related to the normal service operation is assigned. In addition, a number of occurrences of the event is tracked and t
Bruch Xavier
Girones Xavier
Vega Ramon
Hewlett--Packard Development Company, L.P.
Nguyen Lam
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