Patent Grant
9285730
The present invention relates to a method for determining a characteristic of a surface layer of a fuser element for fusing a marking material on a recording medium in a printing system. The present invention further relates to a printing system comprising a fuser element and a capacitive probe for determining a characteristic of a surface layer of the fuser element.
In a known printing system a fuser element is provided for fusing a marking material on a recording medium. The fuser element has a surface layer, which contains an elastomeric compound, configured for providing a uniform pressure to the marking material in a fusing pinch.
The surface layer of the fuser element deteriorates in operation of the printing system due to mechanical wear in the fusing pinch. As a result in the long term a characteristic of the surface layer will change. In general a thickness of the surface layer slowly decreases. Moreover the thickness of the surface layer becomes non-uniform in a direction of the fusing element during use of the fuser element, for example in a direction parallel to an extending direction of the fusing pinch.
The thickness and life time of the surface layer of the fuser element in a printing system is often predicted based on the number of images fused on recording mediums in the printing system and on a predetermined wear behavior of the fuser element. The wear behavior is predetermined by a manufacturer of the fuser element in a controlled test environment.
In practice a fuser element in a printing system is replaced earlier than necessary, as the actual thickness of the surface layer of the fuser element in the printing system also varies due to other uncontrolled parameters.
It is accordingly an object of the present invention to provide a method for determining a characteristic of a surface layer of a fuser element for fusing a marking material on a recording medium in a printing system that provides knowledge on the actual wear characteristic of the surface layer of the fuser element in the printing system.
This object is attained by a method for determining a characteristic of a surface layer of a fuser element for fusing a marking material on a recording medium in a printing system, the printing system comprising a capacitive probe comprising a first electrode and a second electrode, the second electrode being arranged adjacent to the first electrode in order to form a capacitor, the first electrode and the second electrode in operation both being arranged adjacent to and opposing the surface layer of the fuser element, the method comprising the steps of:
The characteristic of the surface layer of the fuser element may be a thickness of the surface layer, may be a contamination on the surface layer (for example a paper dust or an oil smudge on top of the surface layer), may be a density of the surface layer, may be a composition of the surface layer and may be any other characteristic which can be determined by performing a capacitive measurement on the surface layer of the fuser element.
The first and the second electrode are operatively coupled to form a capacitor. The first electrode and the second electrode in operation are both arranged adjacent to and opposing the surface layer of the fuser element. The first electrode and second electrode are arranged substantially parallel to the surface layer. The first electrode and the second electrode may be temporarily arranged adjacent to and opposing the surface layer of the fuser element in the printing system, e.g. during a measurement operation of the printing system, and may be permanently arranged adjacent to and opposing the surface layer of the fuser element in the printing system.
The capacitive measurement on the surface layer of the fuser element is a simple and fast measurement, which can be carried out automatically in a printing system. Based on the capacitive measurement the characteristic of the surface layer of the fuser element can be monitored during life time of the fuser element.
The surface layer may comprise an elastomeric compound, may comprise a release fluid component, such as a silicon oil component, for releasing a marking material in a fusing pinch, may comprise a mechanical friction reduction component, such as a perfluoroalkylene polymer particle (e.g. Teflon), and may comprise an electro conductive component, such as a carbon particle.
The surface layer of the fuser element is an outer layer of the fuser element, which contacts the marking material and/or the recording medium during fusing of the marking material on the recording medium.
The capacitive probe comprises a first electrode and a second electrode, wherein the second electrode is arranged adjacent to the first electrode. The first electrode and the second electrode may be a plate electrode. The first electrode may be the same in area as the second electrode. The second electrode may also surround the first electrode. For example the first electrode may be a small diameter wire center electrode being enclosed by the second electrode, wherein the first electrode is coated with a thin electrically insulating coating.
The first electrode and second electrode may be arranged substantially parallel to each other. The first electrode and the second electrode may be arranged with respect to the surface layer in order to be equal in distance from the surface layer.
In the measurement step a) a capacitive measurement is performed by the capacitive probe on the surface layer of the fuser element. It is known to a person skilled in the art how to suitably select a distance between the first electrode and the second electrode and select a distance between both the first electrode and the second electrode in order to perform a capacitive measurement on the surface layer.
Furthermore it is known to a person skilled in the art how to measure a capacity of the capacitor formed by the first electrode and the second electrode. In particular it is known how to suitably select a potential for measuring a capacity of the capacitor.
In the determination step b) a characteristic of the surface layer of the fuser element is determined based on the capacitive measurement of step a). The characteristic may be determined based on a difference between the capacitive measurement of step a) and a predetermined capacitive measurement. For example a predetermined capacitive measurement of a starting characteristic of the surface layer of the fuser element before use in a printing system.
In an embodiment of the method, step b) comprises determining a thickness of the surface layer of the fuser element based on the capacitive measurement of step a). The thickness of the surface layer of the fuser element is a measure for the quality of fusing a marking material on a recording medium.
In an embodiment of the method, step b) comprises determining a contamination on the surface layer of the fuser element based on the capacitive measurement of step a). In fusing applications several contamination sources are known, such as paper residues, oil residues and glue residues. For example, in case the capacitive probe contacts the surface layer during step a), a paper dust particle on top of the surface layer of the fuser element will locally change the capacitive measurement of the capacitive probe at the position of the paper dust particle.
An occasional occurring contamination on the surface layer can be distinguished from a gradually changing surface layer thickness when regularly performing a capacitive measurement on the surface layer and monitoring the rate of the changing characteristic. In this way a position and a size of a paper dust contamination can be determined accurately and a maintenance process may be initiated in order to remove the paper dust contamination from the surface layer. Furthermore the success of a maintenance action may be determined by performing a capacitive measurement before and after the maintenance action.
In an embodiment of the method, step a) comprises positioning the first electrode and the second electrode spaced apart at a predetermined distance from the surface layer of the fuser element in order to form a capacitor gap with a gas between both the first electrode and the second electrode of the capacitive probe and the surface layer of the fuser element. The capacitor gap having the predetermined distance from the surface layer provides an accurate capacitive measurement while preventing mechanical wear of the surface layer during the measurement step.
In the method according to the present invention, the capacitive probe further comprises a dielectric surface layer, wherein step a) comprises positioning the dielectric surface layer of the capacitive probe in contact with the surface layer of the fuser element in order to form a capacitor with the dielectric surface layer between both the first electrode and the second electrode of the capacitive probe and the surface layer of the fuser element. The dielectric surface layer provides an accurate capacitive measurement by providing a controlled distance and a controlled dielectric layer between both the first and the second electrode and the surface layer.
In an embodiment said dielectric surface layer is a semiconducting layer. According to this embodiment of the invention, said semiconducting layer may be formed, for example, by a known sputtering process, consisting of an oxide or nitride, such as silicon oxide, aluminum oxide, silicon nitride and zinc oxide, the oxygen or nitrogen proportion of which in the molecular lattice is suitably selected for providing a semiconducting property.
Said semiconducting layer improves the determining step of a characteristic of the surface layer of the fuser element. For example, in case the surface layer of the fuser element is a (semi)conducting surface layer, said semiconducting layer of the capacitive probe enhances the determination of the thickness of the surface layer of the fuser element.
Furthermore in case a contamination is present on top of the surface layer of the fuser element, said contamination may be determined more accurate when using a semiconducting layer as the dielectric surface layer of the capacitive probe.
For example for a silicon oxide (SiOx) semiconducting layer it is known to select the oxygen proportion x (i.e. is the ratio O/Si) lower than 1.5 in order to achieve an electrical conductivity higher than 10−12 Ω−1 cm−1 at room temperature.
In a particular embodiment said dielectric surface layer comprises silicon oxide (SiOx), wherein x is on the average in the range of 0.4-1.4. Said embodiment provides an electrical conductivity in the range of approximately 10−6 Ω−1 cm−1 to 10−10 Ω−1 cm−1 at room temperature.
In an embodiment said dielectric surface layer comprises a layer of silicon oxide comprising a bottom portion of the dielectric surface layer, which is arranged in electrical connection to the first electrode and the second electrode, consisting of SiOx where x is approximately or on the average of about 0.40-0.65, and a top portion of the dielectric surface layer, which is arranged adjacent to an outer surface of the dielectric surface layer, consisting of SiOx, where x is approximately or on the average of about 1.2-1.6. Said dielectric surface layer further improves the accuracy of the capacitive probe.
In an embodiment of the method, the fuser element is rotatably arranged around an axis and wherein step a) comprises performing a plurality of capacitive measurements while rotating the fuser element around the axis. By rotating the fuser element around the axis easily a plurality of capacitive measurements can be performed on the surface layer while maintaining the capacitive probe at the same position with respect to the fuser element.
In an embodiment of the method, the capacitive probe comprises at least three electrodes, wherein the at least three electrodes are in operation distributed along an axial direction of the fuser element, and wherein step a) comprises performing a plurality of capacitive measurements along the axial direction of the fuser element, wherein each of the plurality of capacitive measurement is being performed by two adjacent electrodes of the at least three electrodes. By suitably selecting two adjacent electrodes of the at least three electrodes easily a plurality of capacitive measurements can be performed on the surface layer along the axial direction of the fuser element.
In an embodiment of the method, step a) comprises step a1) moving the capacitive probe and the fuser element relative to each other in an axial direction of the fuser element and step a2) performing a plurality of capacitive measurements along the axial direction of the fuser element. In a particular embodiment the capacitive probe is moved in the axial direction along the fuser element. A plurality of capacitive measurements along the axial direction of the fuser element can easily be obtained by moving the capacitive probe and the fuser element relative to each other in the axial direction. The capacitive probe may be designed small and light-weighted, due to comprising merely the first electrode and the second electrode, suitable for fast and accurate movement of the capacitive probe.
In an embodiment of the method, step a) comprises changing the potential of the first electrode by a predetermined voltage and measuring the amount of charge flowing to or from the second electrode in response to the change in potential of the first electrode. Embodiment provides a simple and accurate capacitive measurement.
The invention relates further to a printing system for providing a marking material on a recording medium comprising:
The printing system may be a toner printing system and may be an inkjet printing system. The marking material may be toner, may be ink, and may be any other material suitable for providing an image on a recording medium.
The fuser element may be a fuser belt and may be a fuser roller.
The capacitive measurement circuit is operatively coupled to the first electrode and the second electrode of the capacitive probe in order to perform a capacitive measurement. The capacitive probe is in operation arranged with respect to the surface layer of the fuser element for performing a capacitive measurement on the surface layer of the fuser element.
In the printing system, the capacitive probe comprises a dielectric surface layer, the dielectric surface layer in operative condition being engaged against the surface layer of the fuser element. The dielectric surface layer provides an accurate capacitive measurement by providing a controlled distance and a controlled dielectric layer between both the first and the second electrode and the surface layer.
In an embodiment of the printing system, the capacitive probe comprises at least three electrodes, the at least three electrodes in operative condition being distributed along an axial direction of the fuser element. By suitably selecting two adjacent electrodes of the at least three electrodes easily a plurality of capacitive measurements can be performed on the surface layer along the axial direction of the fuser element.
In a particular embodiment of the printing system, the printing system further comprises an image forming element, wherein the capacitive probe is configured for in printing operation image-wise developing the marking material on a surface of the image forming element by providing a potential on each of the at least three electrodes of the capacitive probe. In a particular embodiment the image forming element and the capacitive probe are the same, wherein the at least three electrodes are arranged inside the surface of the image forming element. The image forming element is arranged adjacent to the fuser element in printing operation for transferring the image to the fuser element. The image forming element can be used both in printing operation for image-wise developing the marking material on the surface of the image forming element and transferring the image to the surface layer of the fuser element and in measurement operation for performing a capacitive measurement on the surface layer of the fuser element.
In an embodiment of the printing system, the printing system further comprises a capacitive probe scanning device, which is configured for in operation moving the capacitive probe along an axial direction of the fuser element. The capacitive probe scanning device may comprise a linear driving motor, may comprise a belt, may comprise a reference pattern and may comprise a distance unit for maintaining the capacitive probe at a distance from the surface layer of the fuser element. A plurality of capacitive measurements along the axial direction of the fuser element can easily be obtained by moving the capacitive probe and the fuser element relative to each other in the axial direction.
In an embodiment of the printing system, the fuser element is an intermediate image transfer element configured for, in operation of the printing system, transferring the marking material to the recording medium. The intermediate image transfer element may be a belt and may be a roller. The intermediate image transfer element may in a first transfer position (e.g. a transfer pinch) receive an image consisting of the marking material and may in a second transfer position (e.g. a transfuse pinch) transfer the image consisting of the marking material to the recording medium while fusing the marking material on the recording medium.
In an embodiment of the printing system, the surface layer of the fuser element comprises an elastomeric material. The elastomeric material may be suitably selected for providing a uniform pressure in a fusing pinch.
In an embodiment of the printing system, the surface layer of the fuser element comprises an electro conductive component.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.
Hereinafter, the present invention is further elucidated with reference to the appended drawings showing non-limiting embodiments and wherein
The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals have been used to identify the same or similar elements throughout the several views.
The image data are supplied to the print engine through a data connection 2. This may be any suitable data connection, depending among other things on the required bandwidth. The digital image converter 1 comprises electronic circuits including programmable logic to convert an image line into a print signal that is suitable to be applied to the image forming module 10 through a data connection 3. In
Alternatively the image forming element 11 may comprise a roller with a photoconductive layer on the outside surface of the roller. In such embodiment the surface of the photoconductive layer is charged by e.g. a corona and the print signals are applied to an imaging unit outside the roller. The imaging unit may comprise a LED-bar, or a laser scan module, that locally illuminates the layer conform the image to be printed. The photoconductivity of the layer results in a locally discharged surface. The parts of the photoconductive layer that remain charged may be used to attract toner from a toner roller like developing roller 15 by creating an electric field between these charged parts and the toner roller. In an embodiment an electric field between the charged parts and the toner roller may be provided by connecting the toner roller to a ground voltage. The toner may comprise electrically conductive particles having a specified color or a mixture of isolating colored particles and carrier particles that charge the isolating particles, making them sensitive to an electric field between the developing roller and the image forming element. Instead of carrier particles the developing roller may also be supplemented by a contact roller that charges the toner particles. Therefore there are various ways to obtain an image of toner particles on the surface of the image forming element. In the process of forming the image the element rotates in the direction indicated by the arrow in
The intermediate member 16 comprises a belt 17 and two guiding rollers 18, but more rollers are also possible. The belt 17 rotates in congruence with the image forming element 11 and receives the toner image in a nip where the image forming element 11 and the belt 17 are in contact. The transfer of toner may take place by the influence of mechanical forces that are induced when the top layer of the belt comprises an elastic, adhesive material, such as rubber, or by the influence of electric forces that originate from a voltage difference between the image forming element and the belt. The intermediate member 16 may further comprise a heating unit, which is not shown in
The image fixing module 20 is able to transport an image receiving member, such as a sheet of paper, by transport rollers 21 and guiding means 22 to a pressure roller 23 that brings the image receiving member into contact with the belt 17 of the intermediate member 16. The image receiving member is supplied by an image receiving member input station 30 comprising a pile of sheets 31. By applying heat and pressure the toner is brought onto the image receiving member, which is transported further towards the post processing unit 40. The image fixing module may comprise a path for turning the image receiving member to be able to print another side. The fuser rollers 24 raise the temperature of the image receiving member to further fix the printed image on the image receiving member and to enhance the printed image quality. When the temperature of the pressure roller 23 is sufficiently high, no fuser rollers are necessary.
The post processing unit 40 is shown as a support tray 41, on which different sheets may be stacked, but may also comprise a stapler, a hole puncher etc. for performing a post processing step. The various modules are controlled by a control unit to have their actions coordinated.
A capacitive probe 120 is arranged adjacent to the surface layer 110 of the fuser roller 24. The capacitive probe 120 is operatively coupled to a capacitive measurement circuit 130 for measuring a capacity by the capacitive probe 120 and determining a characteristic of the surface layer 110.
During a capacitive measurement cycle the potential of the first electrode 122 is changed by a predetermined voltage. An electric field E is generated towards the second electrode 124, schematically indicated by arrow E, which passes through the gap 126 and passes through the surface layer 110. At the same time an amount of charge flowing to or from the second electrode 124 in response to the change in potential of the first electrode 122 is measured. The predetermined voltage of the first electrode 122 and the distance D are suitably selected in order to measure a permittivity of the surface layer 110. Based on the capacitive measurement a thickness of the surface layer 110 is determined by comparing the result of the capacitive measurement with a predetermined capacitive constant of the surface layer 110 in a known state (e.g. initial state), in which state the thickness is known.
The capacitive probe 120 is movably arranged in a direction parallel to the surface layer 110 and parallel to the axial direction A, as is indicated by arrow S. The capacitive probe 120 in a next step may be moved in the axial direction A by a capacitive scanning device (not shown), which comprises a linear motor and a linear encoder configured for accurately positioning the capacitive probe 120 along the axial direction A. A plurality of capacitive measurements is performed at a plurality of positions of the surface layer along the axial direction A. The capacitive measurement circuit 130 determines for each capacitive measurement a thickness of the surface layer 110 at the respective position. In this way a variation of the thickness of the surface layer 110 in the axial direction A is determined.
Furthermore in another step the fuser element can be rotated in the direction R (as shown in
During a capacitive measurement cycle the potential of the first electrode 222 is changed by a predetermined voltage. An electric field E is generated from the first electrode 222 to the surrounding second electrode 224, schematically indicated by two arrows E, which passes through the gap 226 and through the surface layer 110. At the same time an amount of charge flowing to or from the second electrode 224 in response to the change in potential of the first electrode 222 is measured. The predetermined voltage of the first electrode 222 and the distance D are suitably selected in order to measure a permittivity of the surface layer 110. Based on the capacitive measurement a thickness of the surface layer 110 is determined by comparing the result of the capacitive measurement with a predetermined capacitive constant of the surface layer 110 in a known state (e.g. initial state), in which state the thickness is known.
The capacitive probe 220 is movably arranged in a direction parallel to the surface layer 110 and parallel to the axial direction A, as is indicated by arrow S. A plurality of capacitive measurements is performed in a next step at a plurality of positions of the surface layer along the axial direction. The capacitive measurement circuit 230 determines for each capacitive measurement a thickness of the surface layer 110. In this way a variation of the thickness of the surface layer 110 in the axial direction is determined.
Furthermore in another step the fuser roller 24 is rotated in the direction R (as shown in
The capacitive probe 240 is movably arranged with respect to the fuser roller 24, as indicated by arrow L. The capacitive probe 240 may be positioned in contact with the surface layer 110 and may be lifted from the surface layer 110. The capacitive probe 110 may also be forced against the surface layer 110 at a suitably selected force in order to enhance the contact between the capacitive probe 240 and the surface layer 110. Based on the capacitive measurement a thickness of the surface layer 110 is determined by comparing the result of the capacitive measurement with a predetermined capacitive constant of the surface layer 110 in a known state (e.g. initial state), in which state the thickness is known.
During a capacitive measurement cycle the potential of the first electrode 242 is changed by a predetermined voltage. An electric field E is generated towards the second electrode 244, indicated by arrow E, which passes through the dielectric surface layer 246 and through the surface layer 110. At the same time an amount of charge flowing to or from the second electrode in response to the change in potential of the first electrode is measured. The thickness T and a dielectric property of the dielectric surface layer 246, and the predetermined voltage of the first electrode 222 are suitably selected in order to measure a permittivity of the surface layer 110.
In an embodiment of the present invention said dielectric surface layer is a semiconducting layer. According to this embodiment, said semiconducting layer may be formed, for example, by a known sputtering process, consisting of an oxide or nitride, such as silicon oxide, aluminum oxide, silicon nitride and zinc oxide, the oxygen or nitrogen proportion of which in the molecular lattice is suitably selected for providing a semiconducting property.
Said semiconducting layer improves the determining step of a characteristic of the surface layer of the fuser element. For example, in case the surface layer of the fuser element is a (semi)conducting surface layer, said semiconducting layer of the capacitive probe enhances the determination of the thickness of the surface layer of the fuser element.
Furthermore in case a contamination is present on top of the surface layer of the fuser element, said contamination may be determined more accurate when using a semiconducting layer as the dielectric surface layer of the capacitive probe.
Examples of Semiconducting Dielectric Surface Layers
For example for a silicon oxide (SiOx) semiconducting layer it is known to select the oxygen proportion x (i.e. is the ratio O/Si) lower than 1.5 in order to achieve an electrical conductivity higher than 10−12 Ω−1 cm−1 at room temperature.
In a particular example said dielectric surface layer 246 comprises silicon oxide (SiOx), wherein x is on the average in the range of 0.4-1.4. Said embodiment provides an electrical conductivity in the range of approximately 10−6 Ω−1 cm−1 to 10−10 Ω−1 cm−1 at room temperature.
In a particular example said dielectric surface layer 246 comprises a layer of silicon oxide comprising a bottom portion of the dielectric surface layer, which is arranged in electrical connection to the first electrode and the second electrode, consisting of SiOx where x is approximately or on the average of about 0.40-0.65, and a top portion of the dielectric surface layer, which is arranged adjacent to an outer surface of the dielectric surface layer, consisting of SiOx, where x is approximately or on the average of about 1.2-1.6. Said outer surface of the dielectric surface layer may be arranged into contact with a surface layer of a fuser element. Said dielectric surface layer further improves the accuracy of the capacitive probe.
In an example for providing a dielectric surface layer 246 on top of the first electrode 242 and second electrode 244 a silicon oxide layer may be applied by a known sputter technique in a vacuum chamber, e.g. of the Balzers LLS 801 type, silicon being sputtered from a silicon target with the introduction of argon and oxygen into the chamber, and in the first phase of the sputtering process the supply of oxygen is so set that SiOx, wherein x=±0.5, is applied and in the second phase of the process the oxygen supply is increased so that SiOx, wherein x=±1.5, is formed. The quantity of oxygen to be introduced to achieve the required SiOx composition can be determined by experiment by making a number of samples by varying the quantity of oxygen introduced and determining the silicon/oxygen ratio of the SiOx layer on the various samples by EDX analysis (Energy Dispersive X-ray Analysis). Before the samples are analyzed the analyzer (Tracor TN 5500 of Tracor Europe, Amersfoort, Netherlands) is calibrated with a reference standard of at least 99.9% Si02. A layer of carbon some tens of nanometers thick is vapor coated over the SiOx layer of the samples to be measured, as is known with EDX analysis. This vapor coated carbon layer is also present on the reference standard.
As such a dielectric surface layer 246 is formed having a thickness of about 0.8 μm-1.5 μm, having a bottom portion in a thickness of about 0.2 μm-0.75 μm consisting of SiOx where x=±0.5 and a top portion consists in a thickness of about 0.2 μm-0.75 μm consisting of SiOx where x=±1.5.
A marking material 352 is developed on the image forming element 11, which is an image drum. The imaging drum 11 comprises a plurality of imaging electrodes 320, which are distributed in an axial direction (indicated by axis A) of the imaging drum 11. The plurality of imaging electrodes 320 are provided under a dielectric surface layer, each of the plurality of imaging electrodes 320 extending parallel to each other in a radial direction of the image forming element 11. The imaging drum 11 and a direct imaging process are further disclosed in EP 191521. The imaging drum 11 forms together with the fuser belt 17 and an pressure roller 306 an image transfer nip 330 for transferring the marking material 352 (or transferring an image constituted by the marking material 352) from the imaging drum 11 to the fuser belt 17. The imaging drum 11 is rotatably arranged in a direction as indicated by arrow R2. An image comprising a marking material 353, which has been transferred from the imaging drum 11 to the surface layer 310 of the fuser belt, is transported by the fuser belt 17 to the transfuse nip 340 as indicated by arrow M. In the transfuse nip 340 a marking material 354 is transferred, and optionally fused, to the recording medium 31.
In
During a first capacitive measurement cycle the potential of the first electrode 322 is changed by a predetermined voltage. An electric field E is generated towards the second electrode 324, indicated by arrow E1, which passes through the dielectric surface layer 331 and through the surface layer 310. At the same time an amount of charge flowing to or from the second electrode in response to the change in potential of the first electrode is measured.
During a second capacitive measurement cycle the potential of the second electrode 324 is changed by a predetermined voltage. An electric field E is generated towards the third electrode 326, indicated by arrow E2, which passes through the dielectric surface layer 331 and through the surface layer 310. At the same time an amount of charge flowing to or from the third electrode 326 in response to the change in potential of the second electrode 324 is measured.
During a third capacitive measurement cycle the potential of the third electrode 326 is changed by a predetermined voltage. An electric field E is generated towards the fourth electrode 328, indicated by arrow E3, which passes through the dielectric surface layer 331 and through the surface layer 310. At the same time an amount of charge flowing to or from the fourth electrode 328 in response to the change in potential of the third electrode 328 is measured.
A person skilled in the art may contemplate that like-wise each two adjacent electrodes of the plurality of electrodes 320 may be used in a capacitive measurement in order to measure a plurality of portions of the surface layer 310 in the axial direction A.
Furthermore in another step of the embodiments shown in
During the capacitive measurement cycle the potential of the first electrode 322 and the second electrode 324 is changed by a predetermined voltage. An electric field E is generated from the first electrode 322 towards the second electrode 324, schematically indicated by arrow E, which passes through the gap 313 between dielectric surface layer 331 and the surface layer 310. At the same time an amount of charge flowing to or from the second electrode 324 in response to the change in potential of the first electrode 322 is measured.
The result of the capacitive measurement is different from a situation when no paper dust particle is present as the gap 313 and the paper dust particle 314 have a substantially different dielectric property than the surface layer 310 of the fuser element. Based on the capacitive measurement the position and size of the paper dust contamination is determined. A maintenance action may be initiated to remove the paper dust contamination.
Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. In particular, features presented and described in separate dependent claims may be applied in combination and any advantageous combination of such claims is herewith disclosed.
Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. The terms “a” or “an”, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 12182981 | Sep 2012 | EP | regional |
This application is a continuation of PCT International Application No. PCT/EP2013/068257, filed on Sep. 4, 2013, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 12182981.6, filed in European on Sep. 4, 2012, all of which are hereby expressly incorporated by reference into the present application.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5003325 | Bibl | Mar 1991 | A |
| 6370965 | Knapp | Apr 2002 | B1 |
| 20020024345 | Stein et al. | Feb 2002 | A1 |
| 20060152231 | Konermann et al. | Jul 2006 | A1 |
| 20070252718 | Ray | Nov 2007 | A1 |
| 20100256951 | Konermann et al. | Oct 2010 | A1 |
| 20110222894 | Yamamoto et al. | Sep 2011 | A1 |
| 20110299900 | Yonekawa et al. | Dec 2011 | A1 |
| 20130078470 | Murase et al. | Mar 2013 | A1 |
| 20130264211 | Akiyama | Oct 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 2003-5578 | Jan 2003 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20150168891 A1 | Jun 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2013/068257 | Sep 2013 | US |
| Child | 14630374 | US |
