Patent Application
20140205312
The disclosure relates to methods and systems for a cleaning a bias charge roll used to charge a photoreceptor useful in printing systems. In particular, the disclosure relates to cleaning a charging roll surface to extending bias charge roll and photoreceptor useful life for printing.
In a typical electrophotographic printing process, a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. An electrostatic latent image is formed on the photoconductive member corresponding to the informational areas contained within the original document. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. The toner particles are heated to permanently affix the powder image to the copy sheet.
In printing machines such as those described above, a bias charge member roller (BCR) is increasingly used as the major charging apparatus in xerographic systems due to environment friendliness and excellent charging performance. A BCR provides several advantages over traditional scorotron charging: a) uniform and stable charging; b) reduced emissions of ozone or other corona by-products; c) lower AC/DC voltage supply requirements; and d) reduced service maintenance.
The BCR suffers, however, from toner/additive contamination over many printing cycles reducing overall service life of BCR. Significant amounts of effort have been put to suppress the contamination on BCR. For example, U.S. Pat. Nos. 8,126,344; 7,711,285; 7,526,243; 7,266,338; 7,079,786; 6,836,638; 6,470,161 are using dedicated cleaning systems to alleviate the adherence of particles trapped on the cleaning surface of a photoreceptor. On the other hand, U.S. Pat. No. 8,116,655, US20090169237, U.S. Pat. No. 6,381,432, US20040019986, U.S. Pat. No. 7,899,354, U.S. Pat. No. 8,064,791, US20110170896, US20110170897 propose direct cleaning systems to clean BCR surface for extended lifetime.
Constant contact between the cleaning system and the BCR surface over long time periods may cause bleeding and degradation of the BCR surface. Therefore, there is a continuing need for a more effectively configured BCR cleaning system. Related art systems for bias charge roll cleaning exhibit inferior performance in xerographic printing systems, particularly those imaging apparatus using over-coated photoreceptor members. For example, wear of the cleaning blade caused by a hard over-coated photoreceptor contributes to wear of the bias charge roll and accelerates degradation of a bias charging member configured to contact and charge the photoreceptor. Cleaning systems and methods useful for xerographic printing systems including those incorporating over-coated photoreceptors are desired. A vibration-assisted cleaning unit is provided that extends bias charge roll and the imaging apparatus life.
An embodiment of systems may include a xerographic printing system having a bias charge roll; a bias charge roll vibration-assisted cleaning system configured to vibrate a cleaning member, the cleaning system having an actuating unit; and an elastomeric cleaning member, the actuating unit configured for causing the elastomeric cleaning member to vibrate and contact the bias charge roll intermittently. In systems, the actuating unit may be selected from a group consisting essentially of a piezoelectric transducer, an electrical motor, a pneumatic actuator, a hydraulic actuator, a linear actuator, a combo drive, thermal bimorphs, and electroactive polymers.
In systems the actuating unit may be configured to vibrate at a frequency in a range of about 0.1 Hz to about 10 kHz. The actuating unit may be configured to vibrate with a duty cycle in a range of about 5% to about 95%. The actuating unit may be configured to vibrate at an amplitude in a range of about 5 μm to about 1000 μm.
In systems, the elastomeric cleaning member may be selected from a group consisting essentially of a roller, a brush, a pad, and a blade. In systems, the cleaning system may be configured to cause the elastomeric cleaning member to move away from the charge roll during an idle time position for reducing pro-longed contact between the charge roll and the cleaning member. In systems, the actuating unit may be powered by a driving waveform selected from a group consisting of square, sinusoid, and sawtooh. In a preferred embodiment, the actuating unit is a piezoelectric transducer. In systems, the actuating unit being configured whereby a vibrational frequency of the cleaning member is modulated at a time when the cleaning member contacts the charge roll for minimizing friction between the charge roll and the cleaning member.
An embodiment of methods of may include a bias charge roll cleaning method useful for xerographic printing, including causing a charge roll cleaning member to contact a bias charge roll for cleaning a surface of the charge roll in a charge roll cleaning position; and causing the cleaning member to separate from the charge roll to a cleaning member cleaning position. Methods may include causing the cleaning member to vibrate the cleaning member according to a vibration pattern configured for cleaning the cleaning member. Methods may include causing the cleaning member to vibrate in a charge member contact position. Methods may include the causing the member to contact the charge roll further including causing the cleaning member to intermittently contact the charge roll. In embodiments, methods may include causing the cleaning member to vibrate in the charge member cleaning position at a first frequency; and causing the cleaning member to vibrate in the cleaning member cleaning position at a second frequency, the second frequency being different than the first frequency.
An embodiment of apparatus may include an image forming apparatus useful for xerographic printing, which may include a bias charge roll; a photosensitive member for receiving an electrostatic latent image; a development system for applying developer material to said photosensitive member surface; a transfer system for transferring the developed image from said photosensitive member surface to a substrate; a cleaning blade for contacting said photosensitive member surface; and a vibration-assisted cleaning system comprising: an actuating unit to provide said vibration; an elastomeric cleaning member in intermittent contact with said bias charging roll surface to provide cleaning.
Apparatus may include the actuating unit being selected from a group consisting essentially of a piezoelectric transducer, electrical motor, pneumatic actuator, hydraulic actuator, linear actuator, combo drive, thermal bimorphs, and electroactive polymers. Apparatus may include the image forming apparatus wherein the elastomeric cleaning member is selected from a group consisting essentially of a roller, a brush, a pad and a blade. In an embodiment, apparatus may be configured for lifting the elastomeric cleaning member away from said bias charge roll during idle time to prevent long-term contact between said bias charge roll and the elastomeric cleaning member. In an embodiment, apparatus may be configured for modulating the frequency when said elastomeric cleaning member is in the period of contact with the surface portion of the bias charge roll to minimize friction between the bias charge roll and the surface portion of the elastomeric cleaning member.
Exemplary embodiments are described herein. It is envisioned, however, that any system that incorporates features of apparatus and systems described herein are encompassed by the scope and spirit of the exemplary embodiments.
Exemplary embodiments are intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the systems and methods as described herein.
Cleaning systems and methods useful for xerographic printing systems, including those incorporating over-coated photoreceptors are provided. In particular, a vibration-assisted cleaning unit is provided that extends bias charge roll and photoreceptor life.
It has been found that bias charge roll cleaning units such as those that rely on constant contact between a cleaning member and the charge roll cause roll degradation. For example, a cleaning member such as a foam roll causes smoothing of the charge roll surface after only 10 thousand prints using related art systems.
Systems include a vibration-assisted cleaning unit or cleaning system that is operably connected to a power source and controller. The system includes a cleaning member that is configured to vibrate according to controllable vibration patterns. A cleaning system includes the cleaning member, which may be a brush or foam strip or roll. The system includes a vibrating unit such as a PZT-driven vibrating unit connected to the cleaning member. Alternative actuators may include a piezoelectric transducer, an electrical motor, a pneumatic actuator, a hydraulic actuator, a linear actuator, a combo drive, thermal bimorphs, and electroactive polymers or other suitable actuating unit. The actuating unit is connected to a vibrating frequency generator controllable by a now known or later developed controller.
Methods may include causing a cleaning member to contact a bias charge roll surface. Methods may include separating the cleaning member contacting the bias charge roll surface from the bias charge roll surface, and vibrating the cleaning member to remove accumulated particles from the cleaning member. Methods may include vibrating the cleaning member while the cleaning member is contacting the bias charge roll. Methods may include moving the cleaning member to intermittently contact the charging member in a charging member cleaning position.
In accordance with embodiments,
Methods may include causing the cleaning system 321 to cause the cleaning member 325 to contact the photoreceptor surface at S3005. In an embodiment, the cleaning member may not be vibrating at S3005. In another embodiment, the cleaning member may be caused at S3005 to vibrate in a first mode, or charge member cleaning mode. The cleaning system 321 may be controlled to vibrate according to a predetermined photoreceptor charge member cleaning mode pattern, for example a first frequency f1 and first amplitude A1 that causes intermittent contact between the cleaning member 325 and the photoreceptor charge member surface during cleaning. The cleaning system 321 may be configured to cause the cleaning member 325 to separate from the photoreceptor surface at S3007. At the S3007, the cleaning system 321 causes the cleaning member 325 to vibrate in a second mode, a cleaning member cleaning mode, for example, a second frequency f1 and first amplitude A1. The cleaning member 325 may be caused to vibrate at a second frequency, such as a high frequency for removing accumulated additive and toner in the offset position, away from a surface of the photoreceptor.
Methods may include causing the cleaning system 421 to cause the cleaning member 425 to contact the photoreceptor surface at S4005. In an embodiment, the cleaning member may not be vibrating at S4005. In another embodiment, the cleaning member may be caused at S4005 to vibrate in a first mode, a charge member cleaning mode. The cleaning system 421 may be controlled to vibrate according to a photoreceptor charge member cleaning mode pattern, for example a first frequency f1 and first amplitude A1 that causes intermittent contact between the cleaning member 425 and the photoreceptor charge member surface during cleaning.
The cleaning system 421 may be configured to cause the cleaning member 425 to separate from the photoreceptor surface at S4007. At the S4007, the cleaning system 421 causes the cleaning member 425 to vibrate in a second mode, a cleaning member cleaning mode, for example, a second frequency f1 and first amplitude A1. The cleaning member 425 may be caused to vibrate at a high frequency for removing accumulated additive and toner in this offset position, away from a surface of the photoreceptor.
A system in accordance with embodiments included a vibration-assisted cleaning system as disclosed, which was test on a paperless fixture. A customer replaceable unit was used for testing, and included a cleaning system having a PZT actuator, a brush assembly, and a PZT control unit for different frequencies from 0.1 Hz up to 3000 kHz. For comparison, the brush length is only about ⅓ of the full length of the BCR. The photoreceptor was run at a speed of 1 rps. The cleaning system was set at 200 Hz, amplitude at about 100 micrometers in both charge member cleaning and cleaning member cleaning or offset modes (f1=f2; A1=A2 in
Embodiments as disclosed herein may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media.
Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, and the like that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described therein.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art.
