The present invention generally relates to inkjet printers and in particular to a system and method for implementing spit strips to reduce service station fluid waste, to improve throughput and to minimize servicing aerosol.
Conventional ink jet print engines typically contain three primary components generally organized in series. The platen and the service station are included among these components. The platen has a printing area upon which the print media are printed. The service station includes a spittoon receptacle in which print drops are disposed to clear the nozzles. The service station also contains a wiper to wipe clean the printhead during use and a cap to prevent the printhead from drying out during periods of inactivity.
One common problem that ink jet printers encounter is that the ink nozzles of the ink jet printer frequently become plugged or otherwise contaminated with a variety of contaminants, such as dried ink and paper fibers. These contaminants can crust the nozzle internally and externally, preventing the nozzles from operating correctly and in turn lowering the quality of print on the print media. The service station is used to service a printhead to keep the nozzles operating properly.
A typical function of the service station is capping. Capping prevents the printhead from drying out when not in use. Capping uses a cap to provide a seal between the vaporization chamber and the printhead. Capping prevents ink from being drawn by capillary action from within the ink supply through the printhead. Another function of the service station is known as wiping. This function uses a wiping action to remove external debris and contaminants from the nozzles. Ink used in ink jet printers is designed to dry quickly and permanently, and if allowed to dry on the nozzles and not wiped away becomes difficult to remove.
Ink jet printer service stations may be implemented in a plurality of ways. For instance, one type of service station is a passive service station that does not use a motor. Passive service stations, however, are noisy and not very effective, which can lower print quality and shorten printhead life. Another type of service station design uses a motor to operate the service station and a separate motor to feed paper through the printer. There are several problems, however by using a motor to feed the paper and a motor to operate the service station, the printer will be more costly and heavier.
Other service stations generally include a spittoon receptacle in which print drops are disposed to clear the nozzles. The spittoon is conventionally added to the printer increasing the lateral traverse of the throughput through increased scan width. However, the over travel of this type of service station with the spittoon can be problematic. Another problem is the increase in aerosol accumulation of ink on the printer from particulates that do not have the momentum to reach the spittoons. Also, the concentrated ink from a spittoon can be difficult and time consuming to dispose. Further, in some environments, the spittoon can be considered hazardous waste by regulator standards. Therefore, what is needed is a system and method that solves these problems.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention is embodied in a system and method for implementing spit strips to reduce service station fluid waste, and to improve throughput.
The printing system includes a controller, printhead assembly, and a service station assembly, operating to produce an image on a print media. At the start of a printing operation, a first swath either fires ink into a spittoon and then continues printing the image, or fires ink on a leading edge spit strip. The spit strip can be defined as the height of the printhead divided by number of passes for a given printmode being used. On normal swaths, the printhead can produce an image within the margin of the print image on the print media.
In an alternative embodiment, nozzles not being used to print the image on the particular swath will fire outside the image margins onto spit strips. In another alternative embodiment, additionally, on predetermined swaths, the carriage can revert to a wide traverse and nozzles will eject inks into the spittoons. In another embodiment, since spit strips are used, the printer does not include a spittoon.
The invention maintains image quality on the print media afforded by a spittoon, and with a decrease in the difficulty and time required to dispose of ink from the spittoon as part of the service station system. The invention also decreases the quantity of aerosol accumulation of ink on the printing system. The present invention purges the portion of ink in the nozzles that have become dye enriched. Dye enrichment is caused by the evaporation of ink vehicle through nozzles to create overly concentrated ink, which in turn can cause dark corners on the printed document. This is advantageous because using the dye enriched ink on a portion of a document creates an image quality defect in that portion of the document, which is avoided by the present invention.