Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-03-02
2001-10-23
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S014000
Reexamination Certificate
active
06305780
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to serial printers, and, more particularly, to a carriage drive system for a serial printer.
2. Description of the Related Art
Printers with carriage drive systems (“serial printers”) are of a type that drive a printhead driver or firing mechanism (“printhead”) which is generally attached to a frame mechanism, called a carriage or carrier, which moves the printhead back and forth at a given distance from the print media while printing takes place. An ink jet printer is an example of such a serial printer. Carriage drive systems suffer from a number of cyclical disturbances which cause velocity fluctuations during printing. These velocity fluctuations, in turn, cause print registration errors in the final output of the printer. Any system that moves a carriage at a given steady-state velocity will generate disturbances at given, repeatable spatial frequencies in addition to general noise. An example unit would be cycles per inch or cycles per millimeter.
In order to increase the quality of the final print, an attempt is made to drive the carriage in a perfectly smooth manner, with no changes to yaw, pitch, or roll of the carriage assembly while printing. If there are any disturbances introduced into the system, additional, non-ideal error velocity components can be introduced to the printhead, resulting in print registration errors in the final print on the output media. Some specific frequencies that are often a problem are the motor pole and commutation frequencies, timing belt tooth disturbances, and gear or pulley tooth disturbances from any gear or pulley systems in the drive train.
One approach to dealing with these disturbances is to change the system mechanically to dampen out the disturbances affecting the carriage, or otherwise attenuate the disturbances until the system is able to achieve its print registration accuracy requirements. This could take the form of better quality components which create less disturbance, altering the characteristics of the carriage, carriage drive belt, etc., to attenuate the disturbances, or some other such scheme. Alternately, sensors could be used to determine what the disturbances are in real time and adjust the print firings to compensate for them. A problem with all of these known approaches is that they add cost to the printer and/or are detrimental to other aspects of printer performance.
What is needed in the art is a method of improving print registration which does not add to the cost of the printer and does not degrade printer performance.
SUMMARY OF THE INVENTION
The present invention provides a method of reducing print registration errors without incurring the costs involved in reducing the level of underlying disturbances that are introduced into the printhead carriage mechanism during printing.
The present invention provides a system of optimal physical printhead element spacings (for multiple elements placed parallel to the direction of carriage motion), optimal belt tooth and motor designs, and optimal gear train/reduction ratios that reduce or eliminate some or all of the effects of the disturbances in the system on print registration. These optimal mechanical designs can be used separate from, or in conjunction with, any other disturbance reduction method.
The present invention comprises, in one form thereof, a carriage drive system for use in a serial printer. A carriage is movable in transverse directions across a print medium. Each of the transverse directions is substantially perpendicular to a print medium feed direction. A print cartridge is releasably mounted on the carriage and has at least one printhead. The at least one printhead has at least one ink jetting nozzle for jetting ink. The at least one ink jetting nozzle cyclically jets the ink at at least one jetting frequency. A carriage belt is mechanically coupled to the carriage. A transverse drive system drives the carriage belt in the transverse directions. A drive motor is coupled to the drive system. At least one cyclical disturbance exists due to the operation of the carriage belt, the drive system and/or the motor. The at least one cyclical disturbance has at least one disturbance frequency. At least one of the disturbance frequencies is an integer multiple of at least one of the jetting frequencies.
An advantage of the present invention is that print registration is improved without the cost of designing the printer such that the inherent disturbances within the printer are reduced.
Another advantage is that print registration can be improved at any given level of cyclical disturbances within the printer.
REFERENCES:
patent: Re. 30440 (1980-12-01), Jeffrey
patent: 2507852 (1950-05-01), Case
patent: 2934967 (1960-05-01), Worrall, Jr.
patent: 4131898 (1978-12-01), Gamblin
patent: 4232324 (1980-11-01), Tsao
patent: 4378965 (1983-04-01), Ishii et al.
patent: 4401991 (1983-08-01), Martin
patent: 4915674 (1990-04-01), Tanaka et al.
patent: 5109239 (1992-04-01), Cobbs et al.
patent: 5151716 (1992-09-01), Kanemitsu
patent: 5200767 (1993-04-01), Tsukada et al.
patent: 5264769 (1993-11-01), Itoh
patent: 5421789 (1995-06-01), Gregg
patent: 5797691 (1998-08-01), Suzuki
patent: 5914736 (1999-06-01), Tamura
patent: 6045212 (2000-04-01), Ruhe et al.
Askren Benjamin Alan
Leiter Michael Scott
Barlow John
Hallacher Craig A.
Lexmark International Inc.
Taylor & Aust P.C.
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