Some aspects of the disclosure relate to imaging methods, imaging devices, transfer assemblies, and transfer member lubrication assemblies.
Imaging devices capable of printing images upon paper and other media are becoming increasingly popular and used in many applications including color reproduction. For example, laser printers, ink jet printers, and digital printing presses are but a few examples of imaging devices in wide use today for black and white or color imaging.
Digital printing presses are relatively new compared with other printing technologies and may be used in place of other printing arrangements, such as analog printing presses. In one imaging example utilizing a press, a plurality of copies of the same image may be reproduced in relatively high volumes (e.g., printing business cards, catalogs, publications, etc.). Some analog systems may have relatively long set up times for different jobs to be imaged. In these implementations, it may not be desired to use analog systems if a relatively small number of copies of the job are to be reproduced.
According to some aspects of the disclosure, exemplary imaging methods, imaging devices, transfer assemblies, and transfer member lubrication assemblies are described.
According to one embodiment, an imaging method comprises forming a latent image upon a first imaging member, developing the latent image providing a developed image, after the developing, first transferring the developed image to an imaging transfer member, after the first transferring, second transferring the developed image from the transfer member, and lubricating the transfer member during the first and the second transferrings.
According to another embodiment, an imaging device comprises an imaging member configured to provide latent images during imaging operations of the imaging device, a development assembly configured to develop the latent images of the imaging member using a marking agent to provide developed images corresponding to the latent images, an imaging transfer member configured to transfer the developed images from the imaging member, and a lubrication assembly configured to lubricate the transfer member during the transfer of the developed images using the transfer member.
Other embodiments are described in the disclosure.
At least some aspects of the disclosure pertain to imaging methods, imaging devices, transfer assemblies, and transfer member lubrication assemblies. Some more specific embodiments relate to methods and apparatus for implementing imaging operations of hard images upon media, such as forming color images upon paper. As discussed further below, some aspects of the disclosure relate to printing using a digital printing press, for example, configured to perform relatively high volume color printing in one embodiment. In exemplary embodiments discussed below, methods and apparatus of providing a lubricant during imaging operations are provided. The usage of the lubricant reduces friction and assists with the release of developed images in at least some of the embodiments discussed in further detail below. Some aspects of the disclosure are discussed with respect to an exemplary electrophotographic imaging process and apparatus although other imaging configurations for forming hard copy images upon media are possible.
Referring to
Imaging device 1 includes processing circuitry 3, storage circuitry 5, and an image engine 10 in the depicted exemplary configuration. Other configurations of imaging device 1 are possible in other embodiments including more, less or alternative components.
In one embodiment, processing circuitry 3 is arranged to process data (e.g., access and process digital image data corresponding to a color image to be hard imaged upon media), control data access and storage, issue commands, monitor imaging operations and control imaging operations of imaging device 1. Processing circuitry 3 may comprise circuitry configured to implement desired programming provided by appropriate media in at least one embodiment. For example, the processing circuitry 3 may be implemented as one or more of a processor and/or other structure configured to execute executable instructions including, for example, software and/or firmware instructions, and/or hardware circuitry. Exemplary embodiments of processing circuitry 3 include hardware logic, PGA, FPGA, ASIC, state machines, and/or other structures alone or in combination with a processor. These examples of processing circuitry 3 are for illustration and other configurations are possible.
The storage circuitry 5 is configured to store programming such as executable code or instructions (e.g., software and/or firmware), electronic data (e.g., image data), databases, look up tables, or other digital information and may include processor-usable media. Processor-usable media includes any computer program product or article of manufacture 6 which can contain, store, or maintain programming, data and/or digital information for use by or in connection with an instruction execution system including processing circuitry in the exemplary embodiment. For example, exemplary processor-usable media may include any one of physical media such as electronic, magnetic, optical, electromagnetic, infrared or semiconductor media. Some more specific examples of processor-usable media include, but are not limited to, a portable magnetic computer diskette, such as a floppy diskette, zip disk, hard drive, random access memory, read only memory, flash memory, cache memory, and/or other configurations capable of storing programming, data, or other digital information.
At least some embodiments or aspects described herein may be implemented using programming stored within appropriate storage circuitry 5 described above and/or communicated via a network or using other transmission media and configured to control appropriate processing circuitry 3. For example, programming may be provided via appropriate media including for example articles of manufacture 6, embodied within a data signal (e.g., modulated carrier wave, data packets, digital representations, etc.) communicated via an appropriate transmission medium, such as a communications network (e.g., the Internet and/or a private network), wired electrical connection, optical connection and/or electromagnetic energy, for example, via a communications interface (not shown), or provided using other appropriate communication structure or medium. Exemplary programming including processor-usable code may be communicated as a data signal embodied in a carrier wave in but one example.
Image engine 10 is configured to implement electrophotographic imaging operations to form and develop latent images in one possible embodiment. Other imaging techniques or methods may be used to form images in other embodiments.
In the embodiment discussed in further detail below, image engine 10 is configured to implement electrophotographic imaging operations to form latent images responsive to image data and develop the latent images using marking agents of a plurality of different colors. In one illustrative embodiment, the marking agents may be provided in liquid form individually including a liquid carrier (e.g., Isopar L™ available from ExxonMobil Corporation) and one of a plurality of different colors of ink or toner (e.g., respective colors of CMYK in one example) which may be provided by respective reservoirs or tanks. One possible liquid marking agent is ElectroInk® available from Hewlett-Packard Company and as described in “HP Indigo Digital Printing”, Hewlett Packard Company, 2003, the teachings of which are incorporated herein by reference. Other marking agents may be used in other embodiments and other configurations of image engine 10 are possible.
Referring to
As mentioned previously, image engine 10 may be arranged to implement electrophotographic and imaging operations in one embodiment. First imaging member 12 is configured to form or provide latent images corresponding to hard images to be formed upon media. As discussed below with respect to a more specific example of image engine 10 described with respect to
Transfer member 14 may be utilized to transfer the developed images in an exemplary imaging device and may be referred to as an imaging transfer member in at least one configuration. In one embodiment, transfer member 14 may be arranged as an intermediate transfer drum, belt or other suitable structure and may also be referred to as a blanket. In the described implementation, transfer member 14 receives developed images from first imaging member 12 in a first transfer operation and transfers the developed images to second imaging member 16 in a second transfer operation. Transfer member 14 may have an outer surface comprising a relatively soft material, such as silicone rubber or polyurethane, in one embodiment. As discussed in detail below, a lubricant may be applied to the outer surface of transfer member 14 to protect transfer member 14. The lubricant may be provided during imaging operations including during the first and second transfer operations of developed images in one embodiment.
In one embodiment, second imaging member 16 may be media for forming hard copy print images and the transfer member 14 may transfer the developed images directly to the media. In other embodiments, second imaging member 16 may be configured in other different arrangements for receiving developed images, and may be an additional transfer drum in but one example. The second imaging member 16 is downstream from transfer member 14 and may be referred to as a subsequent imaging member is some embodiments.
In some configurations, transfer member 14 may be susceptible to damage. In one embodiment, lubrication assembly 18 is arranged to provide a lubricant to transfer member 14 during imaging operations. For example, in one configuration, lubrication assembly 18 may provide the lubricant directly to the outer surface of the transfer member 14 which is used to transfer developed images. An exemplary lubricant is a lubricating oil or a solid lubricant. In one embodiment, a lubricating oil may comprise an oil having a relatively high molecular weight (e.g., 200-400 amu). For example, the molecular weight of a lubricating oil should be higher than the molecular weight of the liquid carrier of the marking agent in one implementation. In such an implementation, the lubricating oil will remain upon the surface of the transfer member 14 after the carrier has evaporated (e.g., the carrier may comprise 80% of the marking agent at the first transfer and only 5% of the marking agent at the second transfer with the remainder being ink solids).
In some embodiments, it may be possible to apply lubricant intermittently to the surface of transfer member 14 if the lubricant remains on the surface of transfer member 14 for sufficient periods of time. Also, if plural development rotations of transfer member 14 are used to develop an image (e.g., four rotations to apply four colorants of a CMYK process), the lubrication assembly 18 may be configured to only apply the lubricant at a first moment in time before the first rotation of transfer member 14 to apply the lubricant intermediate the transfer member 14 and the marking agent of the image and thereafter at a second moment in time not apply additional lubricant until the next image. The lubrication assembly 18 may be disengaged from contacting the transfer member 14 during periods of time wherein no lubricant is provided to the transfer member 14. In other embodiments, the lubricant is provided continuously to the outer surface of the transfer member 14 during imaging operations.
As discussed in further detail below, the lubricant may assist with one or more of reduction of friction (e.g., reduce friction between media and portions of transfer member 14 which do not include marking agents (i.e., background areas of a developed image) in arrangements where the media contacts the transfer member 14) and release of developed images from transfer member 14 to media. The lubricant may increase releasability of developed images from transfer member 14 compared to arrangements not using a lubricant inasmuch as the lubricant may be provided intermediate an outer surface of transfer member 14 and the developed images and the lubricant may reduce adhesion of the developed images to the outer surface. The operating temperatures may affect the type of lubricant utilized and the lubricant is selected in one implementation for use with the transfer member 14 operating at temperatures in a range from 100 C-180 C. A lubricant suitable for use with the exemplary liquid marking agents described above has product designation Isopar V™ available from ExxonMobil Corporation although other lubricants may be used. Exemplary configurations of lubrication assembly 18 are discussed below with respect to the embodiments of transfer assemblies depicted in
Referring to
Photoconductive drum 22 is arranged to rotate in a counterclockwise direction during imaging operations. A charge roller 30 is arranged to provide an electrical charge upon a photoconductive surface of drum 22 and a writing head (not shown) may generate a laser beam 32 to selectively discharge portions of the charged surface of drum 22 to form latent images. Processing circuitry 3 may access and generate appropriate image data to control the writing head to form desired images in one embodiment. A development assembly 34 may contain a plurality of developers to provide marking agents to the surface of drum 22 to develop the latent images formed thereon. In some exemplary color implementations, the marking agents may be provided simultaneously or in different separations. Following development using the marking agent(s), developed images are transferred to intermediate transfer drum 24 as described further below. A cleaning station 36 may be provided to remove any marking agent not transferred to drum 24 and thereafter subsequent latent images may be formed and developed.
In the illustrated embodiment, media 28 traveling along a paper path of imaging device 1 passes between intermediate transfer drum 24 and impression drum 26. The intermediate transfer drum 24 transfers developed images from photoconductive drum 22 to media 28 in the depicted embodiment. According to the illustrated arrangement of imaging device 1, the media 28 may receive a plurality of colors of different separations on a single pass through drums 24, 26. In other embodiments, different color separations may be separately applied to photoconductive drum 22 in respective revolutions of drum 22. Alternative configurations of imaging device 1 in addition to the arrangement of
Although not shown in
In one embodiment described with respect to
For example, although not shown in
In accordance with the described exemplary implementation, the lubricant is applied to portions of the outer surface of the transfer member 14 which are void of the marking agents of the developed images. More specifically, in the depicted example, the lubricant may be provided to portions of the outer surface prior to the receipt of developed images at location 38 and after developed images have been transferred from transfer member 14 at location 39. In one embodiment, the lubricant is provided intermediate the outer surface of the transfer member 14 and the developed images which are received on top of the lubricant upon the outer surface.
Referring to
Blade 43 may be positioned adjacent to an outer surface of wetting roller 42 and configured to control the thickness of a layer of lubricant provided upon the outer surface of wetting roller 42. Blade 43 may be positioned to provide a thickness of the layer of lubricant in a range of 0.1-0.001 microns upon wetting roller 42 in the illustrated configuration although other thicknesses may be provided in other embodiments.
Referring to
Referring to
Referring to
Although not shown in
Referring to
At a step S10, a latent image may be formed upon an outer surface of photoconductive drum 22.
At a step S12, the latent images formed upon the outer surface of photoconductive drum 22 may be developed using liquid marking agents comprising a plurality of different colors.
At a step S14, a lubricant may be provided to an outer surface of intermediate transfer drum 24. The lubricant may be provided to portions of drum 24 void of marking agents of developed images in exemplary embodiments as discussed above.
At a step S16, marking agents of developed images are transferred from photoconductive drum 22 to portions of an outer surface of intermediate transfer drum 24 having lubricant thereon.
At a step S18, the marking agents of developed images are transferred from the intermediate transfer drum 24 to media 28 in the depicted embodiment.
At least one exemplary embodiment may provide improved operations compared with imaging device configurations which provide lubricants directly to reservoirs of marking agents which supply the marking agents for use by the imaging device. For example, these imaging devices may have drawbacks in which an outer surface of the developed image on a transfer member may also have the lubrication oil which may decrease an attraction between the developed image and the media which receives the developed image (which may reduce small dot transfer). Further, the image adhesion to media and durability upon media may be reduced and other components of the imaging device may be adversely impacted (e.g., polymerization upon a photoconductor due to relatively high molecular weight of some lubricants). Finally, the presence of lubricant may result in foaming within the reservoirs and different amounts of lubricants between developed images and background areas of images may result in image memory upon the photoconductor.
One or more of the arrangements of the imaging devices of the disclosure may have improved blanket to media durability in background areas of developed images, improved fixing or durability of images upon media and improved transfer to media. Furthermore, it is believed that application of lubricants to the transfer member 14 as described provides an increased number of degrees of freedom to choose lubricant types and concentrations which may provide at least some of the above-mentioned benefits and may otherwise be unsuitable for direct application to marking agents within reservoirs which may damage the imaging process (e.g., ink conductivity, surface properties, ink viscosity, etc.). At least some of the disclosed arrangements may have improved release of developed images from the transfer member, increased lifespan of the transfer member, reduced foaming of marking agents, and reduced transfer member image memory.
The exemplary aspects herein have been presented for guidance in construction and/or operation of illustrative embodiments of the disclosure. Applicant(s) hereof consider these described illustrative embodiments to also include, disclose and describe further inventive aspects in addition to those explicitly disclosed. For example, the additional inventive aspects may include less, more and/or alternative features than those described in the illustrative embodiments. In more specific examples, Applicants consider the disclosure to include, disclose and describe methods which include less, more and/or alternative steps than those methods explicitly disclosed as well as apparatus which includes less, more and/or alternative structure than the explicitly disclosed structure.
The protection sought is not to be limited to the disclosed embodiments, which are given by way of example only, but instead is to be limited only by the scope of the appended claims.
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Number | Date | Country |
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0399186 | Nov 1990 | EP |