In some applications, drop detection devices are utilized to detect ink drops ejected by printhead nozzles. Based on the detection of ink drops, the status of a particular nozzle or groups of nozzles can be diagnosed. For example, nozzles through which ink drops are ejected may become clogged or otherwise cease to operate properly. The ink drop detectors can be used to determine whether a printhead actually requires cleaning or other maintenance.
In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
In one embodiment, controller 22 is configured to control the plurality of drop ejectors 12 such that ink droplets 14 are controllably ejected to service station 20. In one embodiment, print media is received adjacent service station 20 such that ink droplets 14 are controllably deposited on the print media.
In one embodiment, light source 16 is configured to project light beam 18 between the plurality of drop ejectors 12 and service station 20. As such, when ink droplets 14 are ejected drop ejectors 12, ink droplets 14 pass through light beam 18 as they drop to service station 20. As an ink droplet 14 passes through light beam 18, light from light beam 18 is scattered in various directions. Light collector 24 is illustrated adjacent light beam 18 and some of the scattered light will enter light collector 24. Light collect 24 is illustrated in dotted lines in
In one embodiment, light collected into light collector 24 from the light scattering that occurred when ink droplet 14 passed through light beam 18 can be used to measure the effectiveness or status of ink droplet 14 from one or more of ejectors 12. For example, if controller 22 directs one particular drop ejector to eject and ink droplet 14 at a particular point in time, corresponding light scattering from ink droplet 14 passing through light beam 18 should enter light collector 24. By monitoring the collected light and correlating it with control signals from controller 24, a determination can be made as to whether an ink droplet 14 did in fact eject, as well as determinations about the size and quality of ink droplet 14.
In one embodiment, light collector 24 includes light detector 26. In one embodiment, a first end of light collector 24 is located adjacent light source 16 and light detector 26 is located at a second end of light collector 24, which is opposite the first end. In one example, light detector 26 is coupled to controller 28, which is configured to process light signals that are collected in light collector 24 and then coupled into light detector 26. In one example, controller 28 may be separate from controller 22, while in other examples, controllers 22 and 28 can be the same controller.
In one embodiment, light source 16 is a collimated light source such as a laser diode device or similar device. In various embodiments, the shape of light beam 18 is circular, elliptical, rectangular or other shape. As ink droplets 14 pass through light beam 18, light is scattered in various directions.
As illustrated in the embodiment, as ink droplet 14 passes through light beam 18, scattered light 17 and 19 is deflected in various orientations. Light will scatter in many directions, but for ease of illustration just a few examples are shown. Some scattered light 17 is directed away from light collector 24, while some scattered light 19 is directed into light collector 24. In one embodiment, light collector 24 is configured to collect scattered light 19 and to direct it to light detector 26 for further processing.
In one embodiment, light collector 24 is a tubular-shaped light pipe that is configured to be adjacent each of a series of drop ejector nozzles 12. As such, as each nozzle 12 ejects an ink droplet 14 through light beam 18, scattered light 19 is collected all along the length of light collector 24. In this way, only a single collector 24 is needed to collect scattered light 19 from a plurality of drop ejectors 12 located along its length. Collector 24 then propagates all of this collected scattered light 19 from the various ink droplets 14 to light detector 26 for further processing.
In one embodiment, light collector 24 is configured with grating 30. In one example, grating 30 has a pitch that is angle to deflect most of scattered light 19 toward light detector 26 in the direction of darkened and dashed arrow 32. In one embodiment, regardless of where scattered light 19 enters light collector 24 along its length, much of the light will be propagated in the direction of arrow 32.
Scattered light 19 that is not deflected in the direction of arrow 32 by grating 30 will generally move in the direction of dashed arrow 34. In one embodiment, light collector 24 is configured with mirror 36 at an end opposite light detector 26. In this way, light scattered in the direction of arrow 34 will be reflected off mirror 36 and back toward light detector 26 in the direction of arrow 34.
In one embodiment, light detector 26 includes a photodetector, or similar sensor of light or other electromagnetic energy capable of detecting scattered light 19 from droplet 14 passing through light beam 18. In one embodiment, light detector 26 includes a charge-coupled device (CCD) array having a plurality of cells that provide sensing functions. The CCD array by means of the plurality of cells detects the light in its various intensities. In one embodiment, light detector 26 receives scattered light 19 and generates an electrical signal that is representative of the scattered light 19.
In one example, controller 22 controls the plurality of drop ejectors 12 such that each is configured to dispense an ink droplet 14 at a specified time. As such, each corresponding ink droplet 14 passes though light beam 18 at a known time the corresponding scattered light 19 collected produces a peak in the output signal that can be correlated by controller 28 in order to verify an ink droplet 14 was indeed produced, and also to verify the quality of ink droplet 14.
For example, controller 28 can analyze the peaks of the output signal to evaluate whether there was an ink droplet 14 or not (detected by the presence of a peak versus the absence of a peak), evaluate ink droplet 14 velocity, or the time that it takes ink droplet 14 to cross light beam 18 (measured by the width of one of the peaks of the output signal), and evaluate ink droplet 14 volume (measured by the cross-section of one of the peaks of the output signal.
Each of these parameters can be useful in certain ink drop arrangements or printers to give an indication of how the system is performing, and also in performing maintenance on the system. For instance, the absence of an ink drop 14 can indicate that a nozzle 12 failed to fire or is misfiring. The presence an ink drop 14 can indicate that the nozzle 12 is firing. The size of the ink drop 14 provides further information pertaining to the working status of the nozzle 12. An ink drop 14 that is smaller than usual indicates that a particular nozzle 12 may be partially clogged or misfiring.
Although
b illustrates light collector 40b, which is similarly provided with grating 44 and core 45 and configured to reflect incoming scattered light 19 primarily in direction 32. In addition, collector 40b also includes first cladding layer 46 adjacent grating 44. As such, scattered light 19 first passed through cladding 46 before engaging grating 44 and propagating down core 45. In one embodiment, first cladding layer 46 provides a protective layer over core 45 to prevent it from scratching and other defects.
c illustrates light collector 40c, which is similarly provided with grating 44, core 45 and first cladding layer 46 and configured to reflect incoming scattered light 19 primarily in direction 32. In addition, collector 40c also includes second cladding layer 48 adjacent core 45, such that core 45 is sandwiched between first and second cladding layers 46 and 48. In one embodiment, the refractive index of the claddings 46 and 48 and of the core 45 can be selected so that total internal reflection is achieved. In this way, the maximum amount of light collected into light collector 40c is transmitted to a light detector. In one example, the refractive index of each of the claddings 46 and 48 is less that of the core 45 enabling total internal reflection. In another example, the refractive index of the claddings 46 and 48 is n=1.5, and the refractive index of the core 45 is n=2.2.
Light collector 24 can have a generally tubular or pipe-like shape, but various other embodiments include a variety of other cross-sectional shapes. For example,
Finally, although several combinations of layers and configurations have been illustrated for light collectors, one skilled in the art will understand that many various combinations and portions of each of these embodiments can be used to achieve various other embodiments.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. For example, the drop detector arrangement 10 could be used in conjunction with a computer printer, or with any of a variety of drop ejection systems while remaining within the spirit and scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
This Application claims the benefit of provisional patent application Ser. No. 61/050,475, filed May 5, 2008 titled “DROP DETECTOR SYSTEM AND METHOD WITH LIGHT COLLECTOR” which application is incorporated by reference herein as if reproduced in full below.
Number | Name | Date | Kind |
---|---|---|---|
5304814 | Markham | Apr 1994 | A |
5589858 | Kadowaki et al. | Dec 1996 | A |
5621524 | Mitani | Apr 1997 | A |
5742303 | Taylor et al. | Apr 1998 | A |
5774141 | Cooper et al. | Jun 1998 | A |
5896145 | Osborne et al. | Apr 1999 | A |
6088134 | Schmidt | Jul 2000 | A |
6168258 | Lou et al. | Jan 2001 | B1 |
6299275 | Elgee | Oct 2001 | B1 |
6513900 | Endo et al. | Feb 2003 | B2 |
6585349 | Lou et al. | Jul 2003 | B1 |
6648444 | Valero et al. | Nov 2003 | B2 |
6747684 | Ornellas et al. | Jun 2004 | B2 |
6767122 | Honguh et al. | Jul 2004 | B2 |
6786626 | Wu et al. | Sep 2004 | B2 |
6802580 | Valero | Oct 2004 | B2 |
6851816 | Wu et al. | Feb 2005 | B2 |
6877838 | Elgee | Apr 2005 | B2 |
6966664 | Wu | Nov 2005 | B2 |
6984013 | Arqullevich et al. | Jan 2006 | B2 |
7055925 | Subirada et al. | Jun 2006 | B2 |
7125151 | Uemura et al. | Oct 2006 | B2 |
7140762 | Wu et al. | Nov 2006 | B2 |
7249830 | Hawkins et al. | Jul 2007 | B2 |
7267467 | Wu et al. | Sep 2007 | B2 |
7287833 | Howard | Oct 2007 | B2 |
7364276 | Piatt et al. | Apr 2008 | B2 |
7442180 | Vitello et al. | Oct 2008 | B2 |
7452053 | Valles et al. | Nov 2008 | B2 |
7490918 | Nagashima | Feb 2009 | B2 |
20010019480 | Fujino et al. | Sep 2001 | A1 |
20050024410 | Subirada et al. | Feb 2005 | A1 |
20060120098 | Ikeda et al. | Jun 2006 | A1 |
20060139392 | Fernandez et al. | Jun 2006 | A1 |
20060187651 | Kim et al. | Aug 2006 | A1 |
20060279601 | Unosawa et al. | Dec 2006 | A1 |
20070024658 | Diol et al. | Feb 2007 | A1 |
20070064068 | Piatt et al. | Mar 2007 | A1 |
20080180471 | Han | Jul 2008 | A1 |
20080246803 | Barger et al. | Oct 2008 | A1 |
20090091595 | Hayashi et al. | Apr 2009 | A1 |
20090141057 | Hayashi et al. | Jun 2009 | A1 |
20090179934 | Takagi et al. | Jul 2009 | A1 |
Number | Date | Country |
---|---|---|
2001113725 | Apr 2001 | JP |
2005083769 | Mar 2005 | JP |
2006-047235 | Feb 2006 | JP |
2006-346906 | Dec 2006 | JP |
2007-119971 | May 2007 | JP |
WO 2007015808 | Feb 2007 | WO |
2009120436 | Oct 2009 | WO |
Number | Date | Country | |
---|---|---|---|
20090273620 A1 | Nov 2009 | US |
Number | Date | Country | |
---|---|---|---|
61050475 | May 2008 | US |