A print apparatus may apply print agents to a paper or another substrate. In one example, a print apparatus may apply a print agent that is an electrostatic printing fluid (e.g., electrostatically chargeable toner or resin colorant particles dispersed or suspended in a carrier fluid). Such a system is commonly referred to as a LEP printing system. In other examples, a print apparatus may apply a print agent via a dry toner or an inkjet printing technology.
A LEP print apparatus includes various components that are to receive a print agent. The print apparatus components may be periodically cleaned to remove residue that would otherwise negatively affect the quality of printed images. However, with certain printing applications, the extent and nature of residue has been such that conventional cleaning methods and systems have not been consistently effective to remove the residue. For instance, a LEP print system may include a print apparatus component (e.g., an amorphous silicon (“aSi”) drum with a photoconductive surface, or a roller in a developer unit) that is susceptible to a build-up of an oxidized imaging oil residue. The oxidized imaging oil residue may be chemically attached to the surface of the print apparatus component, and thereby be difficult to remove. If not removed from the print apparatus component, the residue can cause an unwanted pattern to appear in printed images and thereby significantly affect print quality. In examples, the unwanted pattern may be manifested as a dot area, a streak, or any other errant pattern resulting from pixels on a surface of the print apparatus component not functioning as they should. Further, the accumulation of imaging oil residue can shorten the working life of the affected print apparatus component, requiring frequent replacements and increasing printing costs.
To address these issues, various examples described in more detail below provide a system and a method for cleaning a print apparatus component. In an example of the disclosed method, a print apparatus component to be cleaned is rotated about a rotational axis. A cleaning element, having a cleaning surface in contact with the print apparatus component is rotated. The cleaning element is oscillated in a direction parallel to the rotational axis. The rotation and the oscillation of the cleaning element is varied according to a predetermined function to remove a residue from the print apparatus component.
In an example of the disclosed cleaning system, the system includes a cleaning element having an abrasive cleaning surface. The cleaning element is to contact a print apparatus component that rotates about a first rotational axis. The system includes a rotational driver to cause the cleaning element to rotate about a second rotational axis that is parallel to the first rotational axis. The cleaning system includes an oscillational driver to cause the cleaning element to oscillate in an oscillation direction parallel to the first rotational axis. The cleaning system includes a controller to cause the oscillational driver and the rotational driver to move the cleaning element to remove a residue from the print apparatus component.
In this manner the disclosed method and system provides for effective and efficient removal of residues from a print apparatus component. In particular examples, the disclosed method and system enable use of an abrasive surface to clean oxidized print agent from a photoconductive surface in single drum cycle without negatively affecting performance of the photoconductive surface. Users and providers of LEP printer systems and other printer systems will appreciate the improvements in print quality, the reductions in print apparatus downtime, and the prolonged replacement periods and consumables lifespans that are afforded by utilization of the disclosed examples. Installations and utilization of LEP printers that include the disclosed method and system should thereby be enhanced.
In the example cleaning system 100 of
Continuing with the example of
In another example the rotating print apparatus component to be cleaned by cleaning system 100 may be a developer roller, or other roller, of a developer unit used in LEP printing. As used herein, “developer unit” refers generally to an apparatus that prepares a thin film of electrically charged ink and carrier fluid to a development roller surface. As used herein, “developer roller” refers generally to a roller of the developer unit that directly engages with the photoconductor to apply, through a combination of electrical and mechanical forces, a charged print agent to the photoconductor. In an example, the combination of electrical fields applied to the photoconductor and within the developer unit result in attracting an ink paste to image areas of the photoconductor, and repelling ink paste from non-image areas. The result is replication of the electrostatic latent image that was formed upon the photoconductor with an inked image. As used herein, an “ink” refers generally to any fluid that is to be applied to a substrate during a printing operation to form an image upon the substrate. In examples inks may be, or include, aqueous inks, solvent inks, UV-curable inks, dye sublimation inks, latex inks, liquid electro-photographic inks, liquid or solid toners, or powders. As used herein, the term “print agent” refers generally to any material to any substance that can be applied upon a media by a printer during a printing operation, including but not limited to inks, primers, and overprint materials (such as a varnish).
In certain examples, the photoconductor may engage with an intermediate transfer member (e.g., a blanket), which intermediate transfer member in turn engages with a substrate to convey the developed (sometimes referred to as “inked”) image to the substrate to form a printed image. In other examples, the photoconductor may engage directly with a substrate to form a printed image.
In certain examples, the photoconductor may be attached to a rotatably mounted drum and the blanket may be attached to another rotatably mounted drum, wherein the drums are arranged such that the photoconductor and the blanket each are to rotate about one another during the rotations.
Continuing with the example of
Cleaning system 100 includes the rotational driver 104 to cause cleaning element 102 to rotate about a second rotational axis parallel to the first rotational axis of the print apparatus component. As used herein a “rotational driver” refers generally to any combination of hardware to cause a cleaning element to rotate about an axis. In an example, the rotational driver may include one or all of a set of gears, a set of pulleys, a transmission, and/or a motor.
Continuing with the example of
Cleaning system 100 includes the controller 108 to control movement of rotational driver 104 and movement of oscillational driver 106 to cause cleaning element 102 to remove a residue from the print apparatus component. As used herein, “residue” refers generally to any contaminant or other substance that remains on the print apparatus component to be cleaned after the print apparatus component has been used in a printing operation. In varying examples, the residue may include leftover print agent (e.g., leftover ink, primer or overcoat), or even paper dust. In a particular example, the residue to be removed may be oxidized print agent that accumulated at a print apparatus component (e.g., a photoconductor or a developer roller) during a LEP printing process (e.g., imaging oil and/or ink) at the print apparatus component.
Continuing with the example of
Continuing with the example of
In examples, cleaning system 100 may include a sensor that is to measure reflectance at the surface of the print apparatus component, with different reflectances being indicative of levels of residue at the print apparatus component. In examples, a detected reflectance can be compared with a baseline reflectance or target reflectances (e.g., via a look up table) to identify levels of residue that have accumulated at a print apparatus component. In examples, the sensor utilized to measure reflectance at the print apparatus component may be an optical sensor.
Continuing with the example of
In another example, controller 108 may apply a predetermined function that considers as a variable an extent of wear detected at the cleaning surface 110 of cleaning element 102. In this example, controller 108 may apply the predetermined function to cause rotational driver 104 and oscillational driver 106 to move cleaning element 102 in a manner that decreases oscillation action relative to rotation action as amount of detected wear increases. In an example, controller 108 is to cause oscillational driver 106 to decrease engagement relative to rotational driver 104 engagement responsive to receipt of data indicative that a thickness (e.g., a thickness of cleaning surface 110) of cleaning element 102 has degraded to less than a predetermined tolerance. In this manner the rate of wear upon the cleaning surface 110, and time to replacement, can be decreased.
Continuing with the example of
In an example, the instruction received by controller 108 may be a user instruction initiated by a user via a graphic user interface at a printing apparatus, or at a computing system in network connection with the printing apparatus. In another example, the instruction received by controller 108 may be an instruction generated by a system at a printing apparatus other than cleaning system 100. For instance, controller 108 may receive an instruction for deep cleaning from a print quality system that analyzes printed images for streaking caused by a print apparatus component (e.g., a photoconductor or a developer roller).
In another example, controller 108 may receive an instruction for deep cleaning from a reflectance measurement system that measures reflectance at the surface of a photoconductor, the reflectance measurement system having determined that a deep cleaning is appropriate in view of perceived residue at the print apparatus component. In another example, controller 108 may receive an instruction for deep cleaning from a system that measures electric current between a photoconductor and a developer unit at a printing apparatus, the system having determined that an untenable amount of residue is present at the print apparatus component and that a deep cleaning is appropriate to remove such residue.
The cleaning system 100 at print apparatus 202 includes a cleaning element that is a cleaning cylinder 208, a cleaning cylinder movement mechanism 210, and a controller 212. In an example, cleaning cylinder 208 may be mounted on a cylinder axle to rotate about a second rotational axis parallel to the first rotational axis upon which the drum 204 to be cleaned is to rotate. In this example, cleaning cylinder 208 includes an abrasive cleaning surface 214 that is to contact the photoconductive surface 206 of the drum 204. In a particular example, abrasive cleaning surface 214 of cleaning cylinder 208 may be a hard surface (e.g., a surface including one or more of alumina particles or calcium carbide particles) disposed on an outer surface of an absorbent foam substrate. Cleaning cylinder 208 is to be positioned such that at least part of abrasive cleaning surface 214 engages photoconductive surface 206.
Continuing with the example of
Controller 212 is a combination of hardware and programming that is to control cleaning cylinder movement mechanism 210 such that oscillation of cleaning cylinder 208 in the oscillation direction, and rotation of cleaning cylinder 208 about the second rotational axis, are varied. In examples, hardware of controller 212 may include one or both of a processor and a memory, while the programming may be code stored on that memory and executable by the processor to perform the designated function. In an example, controller 212 may receive data indicative of a degree of residue accumulation at photoconductive surface 206, and dynamically vary the oscillation and the rotation of cleaning cylinder 208 in response to the received data.
Cleaning cylinder 208 is mounted on a cylinder axle 308 to rotate along a second rotational axis 310 that is parallel to first rotational axis 306. Cleaning system 100 has a cleaning cylinder movement mechanism that includes the rotational driver 104 to cause the cleaning cylinder 208 to rotate 314 about the second rotational axis 310, and the oscillational driver 106 to cause the cleaning cylinder 208 to oscillate in an oscillation direction 312 that is parallel to first the rotational axis 306.
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The hashed square depicted at the photoconductive surface 206 of drum 204 is an example of a cleaned portion 402 arbitrarily selected to illustrate how rotation of the cleaning cylinder 208 and the oscillation of cleaning cylinder 208 relative to the rotation of the drum 204 can cause the cleaning cylinder 208 to remove residue from the photoconductive surface 206 with a diagonal wiping line relative to the direction of rotation of the drum 204. Controller 212 is to cause the cleaning cylinder 208 to concurrently rotate around second rotational axis 310 and to oscillate in an oscillation direction 412. A rotation motion 314 of cleaning cylinder 208 if caused by controller 212 to occur by itself would result in a first wiping line 404 that is orthogonal to first rotational axis 306 and second rotational axis 310. An oscillation motion 412 of cleaning cylinder 208, if caused by controller 212 to occur by itself, would result in a second wiping line 406 that is parallel to first rotational axis 306 and second rotational axis 310. In this example, controller 212 is to cause cleaning cylinder 208 to be moved with the rotation motion 314 concurrent with being moved with the oscillation motion 412. This concurrent rotational and oscillational movement is to cause cleaning cylinder 208 to remove residue from photoconductive surface 206 with a resulting diagonal wiping line 408. Because of the oscillation, and the control on the velocities, the wiping direction is changing to cause a more uniform cleaning of photoconductive surface 206. Print quality defects such as streaks that might otherwise occur as a result of residue at the photoconductive surface 206 can thus be greatly reduced, or in some cases, eliminated.
In an example, controller 212 may cause changes in the rotational speed of cleaning cylinder 208 to cause variances in an angle of diagonal wiping line 408. In another example, controller 212 may cause changes in the oscillation speed of cleaning cylinder 208 to cause the angle of diagonal wiping line 408 to be changed. In another example, controller 212 may cause changes in the speed of rotation of drum 204 to cause the angle of diagonal wiping line 408 to be changed. In a particular example, cleaning system 100 may include a biasing element 414 for applying a controlled pressure (e.g., a deflection pressure or force) between cleaning cylinder 208 and drum 204. In this particular example, controller 212 may cause changes in the controlled pressure between drum 204 and cleaning cylinder 208 to cause the angle of diagonal wiping line 408 to be changed. In examples, biasing element 414 may include one or more of a compression spring, an extension spring, or a torsion spring for providing such controlled pressure.
In each of the examples set forth in the preceding paragraph, controller 212 is to cause changes, according to a predetermined function, in cleaning cylinder rotational speed, cleaning cylinder oscillational speed, drum rotation speed, and/or the controlled pressure between the drum 204 and the cleaning cylinder 208. In this manner controller 212 can set cleaning cylinder 208 to operate in an intense cleaning mode, a soft cleaning mode, and/or an abrasive surface preservation mode. In another example, controller 212 may affect cleaning cylinder rotational speed, cleaning cylinder oscillational speed, drum rotation speed, and/or forces exerted as between the drum 204 and the cleaning cylinder 208 according to a predetermined function to set an intensity of cleaning according to a scale, e.g., a scale with 1 being softest cleaning and 100 being the most intense cleaning.
Although the flow diagram of
It is appreciated that the previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these examples will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other examples without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the blocks or stages of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features, blocks and/or stages are mutually exclusive. The terms “first”, “second”, “third” and so on in the claims merely distinguish different elements and, unless otherwise stated, are not to be specifically associated with a particular order or particular numbering of elements in the disclosure.
Filing Document | Filing Date | Country | Kind |
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PCT/US2018/051340 | 9/17/2018 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/060530 | 3/26/2020 | WO | A |
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Number | Date | Country | |
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20210341871 A1 | Nov 2021 | US |