Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-10-19
2003-12-30
Hallacher, Craig (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S022000, C347S037000, C318S600000, C318S615000
Reexamination Certificate
active
06669323
ABSTRACT:
(2) CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable.
(3) STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
(4) REFERENCE TO AN APPENDIX
Not Applicable.
(5) BACKGROUND OF THE INVENTION
(5.1) Field of the Invention
The present invention relates generally to ink-jet technology, more particularly to moveable ink-jet service station mechanisms, and specifically to an algorithm for estimation of mechanical deflection experienced by a service station motion servo during a hard stop event.
(5.2) Description of Related Art
The art of ink-jet technology is relatively well developed. Commercial products such as computer printers, graphics plotters, copiers, facsimile machines, and multifunctional office apparatus employ ink-jet technology for producing hard copy (the term “printer” is used hereinafter to represent such a hard copy apparatus; no limitation on the scope of the invention is intended nor should any be implied therefrom). The basics of this technology are disclosed, for example, in various articles in the
Hewlett
-
Packard Journal
, Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No. 1 (February 1994) editions. Ink-jet devices are also described by W. J. Lloyd and H. T. Taub in
Output Hardcopy [sic] Devices
, chapter 13 (Ed. R. C. Durbeck and S. Sherr, Academic Press, San Diego, 1988).
Ink-jet printheads require routine maintenance as a normal operating procedure. Thus, it is common practice to provide a printhead service station as part of an ink-jet printer. For example, printhead nozzles are tested by spitting ink droplets into service station spittoons; nozzle plates are wiped; nozzle plates are capped between printing cycles; and the like servicing routines are run as would be known to those skilled in the art.
FIG. 1
(Prior Art) schematically shows an exemplary, particular type of translational service station as patented by Hewlett-Packard (common Assignee herein) in U.S. Pat. No. 6,132,026 by Taylor et al. for a INTEGRATED TRANSLATING SERVICE STATION FOR INKJET PRINTHEADS, issued Oct. 17, 2000 and incorporated herein by reference in its entirety. A basic translational service station
60
is located for motion relative to a printhead(s)
54
of an ink-jet pen(s)
50
. The service station
60
has a translating platform, or pallet,
62
which may be driven linearly using a variety of different propulsion devices, such as a rack gear
64
formed along the underside of the pallet and driven by a pinion gear
65
(rotating as indicated by the double-headed arrow labeled
65
′). The pinion gear
65
may be driven by a conventional motor and gear assembly (not shown but represented in phantom line
61
) for translational motion as indicated by double-headed arrow
66
. The pallet
62
carries various servicing components, such as a printhead nozzle plate wiper(s)
68
and cap(s)
69
. The pallet
62
may also carry an absorbent or a non-absorbent purging or spitting station portion
70
, which receives ink that is purged or “spit” from the ink-jet printhead
54
. Located along a recessed spit platform portion
72
of the pallet
60
, the preferred embodiment of spit station
70
includes an absorbent spit target, such as a spit pad
74
, which is preferably made of a porous absorbent material. The spit pad
74
has an exterior surface serving as a target face
75
. Preferably, the pad face
75
is located in close proximity to the printhead
54
during spitting, for instance on the order of 0.5 to 1.0 millimeters (“mm”). This close proximity is particularly well-suited for reducing the amount of airborne ink aerosol. To remove any surface accumulation of ink residue or other debris from the target face
75
, the service station
60
may also include a spit pad scraper device
76
. The illustrated scraper
76
has a support device
78
that mount a blade member
80
to the printer chassis
22
. To engage the target surface
75
with the scraper blade
80
, the pallet
62
moves in the directions of arrow
66
so that the scraper blade can clean the target face
75
. Spit debris is pushed by the scraper blade
80
into a drain, or dump hole,
82
formed through the pallet
62
, which the debris falls through for collection in a bin
84
or other receptacle. So the target scraper
76
does not interfere with the printhead wiper
68
, the wiper has been positioned inboard from the spit pad
74
. To bring the wiper
68
and cap
69
into engagement with the printhead
54
, the pallet
62
is moved in the directions of arrow
66
, with the capped postion being shown in FIG.
1
. The printhead cap
69
is mounted to the pallet
62
using a printhead and/or carriage engaging cap elevation mechanism that includes a spring-biased sled
85
. The sled
85
is coupled to the pallet
62
by two pair of links
86
,
88
, for a total of four links, each to the pallet
62
and the sled
85
(of the four links, only two are visible in
FIG. 1
, with the remaining two links being obscured from view by the two links which are shown). The sled
85
may be biased into the lowered position, shown in cashed lines in
FIG. 1
, by a biasing member such as a spring element
90
. When the carriage
40
has positioned the pen
50
substantially above the service station, the pinion gear
65
dirves the pallet
62
via the rack gear
64
until arms
92
, extending upwardly from the sled
85
engage either the body of the pen
50
or their carriage (not shown). The pinion gear
65
continues to drive the pallet
62
toward the rights as shown in
FIG. 1
, which cause the sled
85
to rise upwardly from the pallet, extending the spring
90
, until the cap
69
engages the the printhead
54
. While the pairs of links
86
,
88
are shown in an upright postion to the cap
69
in
FIG. 1
, an angled orientation with respect to the pallet
62
may also be useful in some implementations, for example, to accomodate slight elevation variations in the printhead
54
. Thus, the pinion gear
65
may drive the pallet
62
, via the rack gear
64
, back and forth in the directions of arrow
66
to position the pallet
62
at various locations to service the printhead
54
. To wipe the printhead, preferably the platform is reciprocated back and forth. To spit through the printhead
54
nozzles to clear any blockages, or to monitor temperature rises, and the like, the platform is moved into a nozzle clearing position where the spit target face
75
is under the printhead. Generally, a programmed servicing routine is performed every certain number of printed pages of printer throughput.
From the foregoing, it can be recognized that with a translational service station, positioning is a critical factor. The goal is to position elements of the service station to within ±0.5 mm or less for all standard service station mechanism moves. To do this, the system requires an accurate measure of an initial position.
In one prior art solution, a switch is mounted at the manufacturing process' targeted “home” position and the mechanism is moved in the direction of the switch until it is triggered, signaling the system that it has reached the home position. One short coming of such a solution is that such switches are relatively expensive piece parts. The use of optical detectors for locating position would be even more expensive.
A simpler prior art solution is to move the mechanism until it reaches a hard stop (e.g., a wall of the chassis
22
). Normal manufacturing processes for such a particular implementation will determine a nominal home position of the service station mechanism. Rather than employing the more expensive mechanisms for determining home position as described in the Background section above, during operation, when motor operation continues following a given short time period when the expected nominal home position should have been reached, the motor is merely shut off. The maximum time period is simply the time required for a full sle
English Kris M.
Harriman Douglas L.
Magnusson Daniel J.
Hallacher Craig
Hewlett--Packard Development Company, L.P.
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