Inkjet printers utilize printheads that include many tiny orifices through which ink is dispensed on to paper or other print substrate. It is desirable for many inkjet printhead assemblies to wipe the surface of each printhead surrounding the dispensing orifices periodically to remove ink residue that may interfere with good quality printing.
The same part numbers designate the same or similar parts throughout the figures.
One undesirable effect of wiping the printheads in an inkjet printer to remove ink residue is the accumulation of ink residue on exposed surfaces around the printheads. In some conventional large format inkjet printers in which high volumes of ink are dispensed from printheads carried by a scanning carriage, a metal shield is permanently installed over the bottom of the carriage around the printheads to protect the carriage against corrosion from ink residue. After a large quantity of ink residue accumulates on the shield, some of the residue can be dislodged during printhead replacement or even during printing and fall on to the print substrate support platen or on to the print substrate.
It has been discovered that new printhead cross-wiping techniques cause ink residue to accumulate on the bottom of the carriage and along the exposed sides of the printheads so that the carriage can no longer survive to its normal end-of-life service replacement. To help resolve this problem, a new, replaceable shield has been developed to protect the carriage. The new shield is easily removed from the carriage assembly and can be replaced before a potentially damaging quantity of ink residue accumulates on the shield, thus regenerating the surfaces around the printheads to minimize the risk of ink residue reaching the print substrate or the platen throughout the normal useful life of the carriage.
The examples shown in the figures and described herein illustrate but do not limit the invention, which is defined in the Claims following this Description.
As used in this document, a “printhead” means that part of an inkjet printer or other inlet type dispenser that dispenses fluid, for example as drops or streams. A “printhead” is not limited to printing with ink but also includes inkjet type dispensing of other fluid and/or for uses other than printing.
A transport mechanism 20 advances paper or other print substrate 22 past carriage 12 and ink pens 16. Pens 16 are connected to printing fluid supplies 24. Although remote supplies 24 are shown, the printing fluids could be located on carriage 12 or contained within each pen 16. A controller 26 is operatively connected to carriage 12, printheads 18 and substrate transport 20. Controller 26 represents generally the programming, processor(s) and associated memory(ies), and the electronic circuitry and components needed to control the operative elements of a printer 10. Controller 26 controls the movement of carriage 12 and substrate transport 20. Controller 28 is electrically connected to each printhead 18 to selectively energize fluid dispensing elements for dispensing ink or other printing fluid in the desired pattern on to substrate 22.
Referring now to
Fluid dispensing orifices 32 on each ink pen 16 are exposed through openings 33 along the bottom surface 34 of carriage 12. In the example shown, orifices 32 are part of a printhead 18 located in a snout 36 of each pen 16 that protrudes through openings 33 in carriage bottom surface 34. Shield 14 includes a cover part 35 with openings 37 corresponding to carriage openings 33 so that cover part 35 covers carriage bottom surface 34 in the areas surrounding pen snouts 36. Although other configurations are possible, it is expected that shield cover part 35 usually will conform to the bottom surface 34 of carriage 12 which, in this example, is flat. Also, in this example, shield 14 includes collars 38 surrounding openings 37 and covering the sides of each pen snout 36. As noted above, one adverse side-effect of the new cross-wiping technique is the accumulation of ink residue on the exposed sides of snout 36. Collars 38 on shield 14 collect ink residue that would otherwise accumulate on the exposed sides of snout 36.
During servicing, ink residue is wiped from the exposed parts of each printhead 18 at orifices 32. Ink residue can spatter onto shield 14 during wiping. As noted above, if a sufficient quantity of ink residue collects on shield 14, some of the residue can be dislodged when a pen 16 is replaced, or even during printing, and fall on to the print substrate support platen or on to the print substrate. To help resolve this problem, shield 14 is attached to carriage 12 with a releasable fastener 40 so that the dirty shield can be easily removed from carriage 12 and replaced with a new or recycled (clean) shield before a potentially damaging quantity of ink residue accumulates on the shield.
In the example shown in
A magnetic or other such easy-release fastener 40 may be desirable in implementations in which shield 14 will be routinely replaced by the user rather than a service technician. However, other suitable releasable fasteners are possible. For examples screws may be desirable in implementations in which shield 14 will last until a routine printer service appointment when a service technician can replace shield 14.
A replaceable shield 14 need not be resistant to the corrosive effects of the ink residue that collects on shield 14, at least not to the same degree as that needed for a permanent shield used in conventional printers. Thus, depending on the desired longevity of the shield and the operating environment (e.g. type of ink and temperatures) an inexpensive molded plastic shield 14 may be used. Suitable materials for a replaceable shield 14 include, for example, less expensive acrylonitrile butadiene styrene (ABS) where lower corrosion resistance is acceptable to more expensive polyphenylene oxide (PPO) where higher corrosion resistance is desired.
“A” and “an” used in the claims means one or more.
As noted at the beginning of this Description, the examples shown in the figures and described above illustrate but do not limit the invention. Other examples are possible. Therefore, the foregoing description should not be construed to limit the scope of the invention, which is defined in the following claims.
Filing Document | Filing Date | Country | Kind |
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PCT/US2013/074878 | 12/13/2013 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2015/088545 | 6/18/2015 | WO | A |
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Entry |
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Meinhart, C.D. et al.; The Flow Structure Inside a Microfabricated Inkjet Printhead ; http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=825779 > On pp. 67-75; vol. 9; Issue: 1; Mar. 2000. |
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Number | Date | Country | |
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20160303856 A1 | Oct 2016 | US |