Aspects of the invention relate to hard imaging device charging systems, liquid electrophotography charging systems, hard imaging apparatuses, and hard imaging device electrophotography charging methods.
Charge rollers (CRs) are used to charge a photoconductor in hard imaging systems (e.g., laser-printer imaging systems). Similar to Scorotron/Corona charging, charge rollers use air ionization to charge a photoconductor. However, a charge roller has increased charging efficiency (close to 100% charging efficiency) and uses lower voltages (˜1500V) compared with Scorotron charging (˜6500V). Charge rollers are typically used in dry (e.g., toner-based) electrophotography processes. In liquid electrophotography processes using a photoconductor having a seam, charge rollers may create print quality defects due to accumulation of imaging fluid in defects or wrap-over sections (e.g., seam regions) on the photoconductor. Movement of the charge roller over a section of the photoconductor having an uneven layer of imaging fluid causes breakdown of the imaging fluid thereby depositing excess imaging oil on the photoconductor during each rotation of the charge roller. The extra imaging oil not only causes disturbance of normal imaging processes but also causes disruption of the Paschen curve and the photoconductor charging voltages, thereby leading to non-uniformity in charging and print quality defects.
Further, the charge roller interacts with the imaging oil and creates a sticky polymer that may coat the photoconductor. The above drawbacks may contribute to photoconductor quality issues by interfering with the photoconductor/blanket image transfer, interfering with image development, and interfering with cleaning of the photoconductor. The above drawbacks may also cause problems relating to photoconductor lateral conductivity, and uneven photoconductor charging. As a result, lifetime of consumables may decrease and the printing cost per page may increase. Furthermore, the created polymer is transferred to the photoconductor at distances corresponding to the circumference of the charge roller. For example, the charge roller during each rotation rolls some of the polymer onto the photoconductor, and the end result is a defect having a shape of the uneven imaging oil layer causing formation of images having decreasing intensities with increasing rotations of the charge roller. Improved imaging devices and methods are desired.
At least some embodiments of the invention relate to hard imaging device charging systems, liquid electrophotography charging systems, hard imaging apparatuses, and hard imaging device electrophotography charging methods.
In one aspect, a hard imaging device charging system is disclosed. The charging system may include a first charging device configured to charge a respective first region of a cylindrical image bearing member used to form latent images during hard imaging operations of the hard imaging device. The charging system may also include a second charging device configured to charge a respective second region of the cylindrical image bearing member used to form latent images during hard imaging operations of the hard imaging device. The first and second regions may have different radii from a central axis of the cylindrical image bearing member.
In another aspect, a hard imaging device electrophotography charging method is disclosed. The method includes charging a first region of a photoconductor using a first charging device, the photoconductor may be used to form latent images during hard imaging operations of the hard imaging device. The method may also include charging a second region of the photoconductor using a second charging device. The first charging may include charging an imaging region of the photoconductor of the hard imaging device, and the second charging may include charging a non-imaging region of the photoconductor.
Other aspects of the invention are disclosed herein as is apparent from the following description and figures.
Referring to
The controller 202 may be configured to control operations of individual components (e.g., 203, 204, 206, 208, 210) of the hard imaging device 100. In one example, the controller 202 may be configured to control operations of the charging assembly 208. As described further below, exemplary operations of the charging assembly 208 include actuation/movement of primary and secondary charge rollers (e.g., reference numerals 402 and 404 of
Formatter 203 may be configured to perform image data processing operations (e.g., rasterization) of data received from an external source (not shown), internally generated, or otherwise accessed.
The laser scanning apparatus 204 may be configured to scan information formatted by the formatter 203 onto image bearing member 206 to form latent images. The laser scanning apparatus 204 may emit a light beam to scan information in one embodiment. The laser scanning apparatus 204 is alternatively referred to as a scanning device.
Image bearing member 206 includes a rotating imaging surface configured to receive information scanned by the laser scanning apparatus 204 in one embodiment. An exemplary image bearing member embodied as image bearing member 206 comprises a steel cylinder having an outwardly exposed layer of photoconductive material. Other embodiments of image bearing member 206 are possible. One or more lines of information (e.g., information formatted by the formatter 203) may be scanned by laser scanning apparatus 204 onto image bearing member 206 to form latent images on the imaging surface of the image bearing member 206 during hard imaging operations of the hard imaging device 100.
The charging assembly 208 may be configured to charge image bearing member 206 to enable forming of latent images on the image bearing member 206. In one embodiment, the charging assembly 208 may have a plurality of charging devices (e.g., a first charging device 402, a second charging device 404 (
The developer/fusing assembly 210 may be configured to develop latent images formed on the image bearing member 206 using a marking agent (e.g., dry or liquid toner), and transfer and fuse the developed image to media 212 (e.g., hard-imaging media such as paper, transparencies, etc.).
Processing circuitry 302 may be configured in one embodiment to issue command signals to an actuator 510 (
In one embodiment, processing circuitry 302 may comprise circuitry configured to execute provided programming. For example, processing circuitry 302 may be implemented as a microprocessor or other structure configured to execute executable instructions of programming including, for example, software and/or firmware instructions. Other exemplary embodiments of processing circuitry 302 include hardware logic, PGA, FPGA, ASIC, and/or other structures. These examples of processing circuitry 302 are for illustration and other configurations are possible for implementing operations discussed herein.
The storage device 304 may be configured to store predetermined value(s) corresponding to clearances between primary charge roller 402, secondary charge roller 404, and image bearing member 206, respectively. The predetermined clearance value(s) may be stored in database 306 of the storage device 304. For example, the predetermined value(s) may be stored in the form of a table in the database 306 of the storage device 304, and the stored information may be configured for retrieval by the processing circuitry 302.
The storage device 304 may also be configured to store electronic data, file systems having one or more electronic files, programming such as executable instructions (e.g., software and/or firmware for use by processing circuitry 302), and/or other digital information and may include processor-usable media. Processor-usable media includes any article of manufacture 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.
Interface 308 may be configured to communicate electronic data externally of the controller 202, for example, received from external devices, with formatter 203 to perform rasterization tasks, and communicate control signals to an actuator 510 (
A voltage supply apparatus 410 is configured to supply voltage to the charging assembly 208 (e.g., primary and secondary charge rollers 402, 404, respectively) to charge respective regions of the image bearing member 206.
As discussed further below, image bearing member 206 comprises a plurality of different regions. The plural regions may correspond to regions of an outer surface of image bearing member 206 having different radii or otherwise spaced different distances from a central axis 207. For example, image bearing member 206 may comprise first and second regions/areas 408, 406 of different radii. In one embodiment, photoconductive material of image bearing member 206 may be provided in a layer 409 about a cylinder. The layer 409 may be joined at a seam region or area. In one example, a second region 406 corresponds to the seam area created during wrapping of imaging or photoconductive material 409 on the cylindrical drum to form the image bearing member 206. A first region 408 corresponds to an area other than the region 406 of the image bearing member 206. In one embodiment, region 408 of the image bearing member 206 is configured to form latent images during hard imaging operations of the hard imaging device 100 (
In one embodiment, roller 402 only charges region 408 and roller 404 only charges region 406. In order to charge region 408 of the image bearing member 206, the primary charge roller 402 may be configured to contact region 408 of the image bearing member 206 in one embodiment or maintain a clearance (e.g., 19 microns or less) with region 408 of the image bearing member 206 according to another embodiment while still providing charging. A position for charging using rollers 402 or 404 may be referred to as a charging position and may include spaced clearance or actual contact of the roller with the respective region of the image bearing member 206. The primary charge roller 402 may be configured to maintain a desired clearance (e.g., greater than 200 microns) with region 406 of the image bearing member 206 in order to avoid charging of region 406. A position used to avoid charging may be referred to as an insulation or insulating position.
In order to charge region 406 of the image bearing member 206, the secondary charge roller 404 may be may be provided in the charging position relative to region 406. The secondary charge roller 404 may be provided in an insulation position with respect to region 408 in order to avoid charging of region 408.
In one embodiment as mentioned above, roller 402 only charges region 408 and roller 404 only charges region 406. For example, the primary and secondary charge rollers 402, 404, respectively, may be individually provided within the charging positions with respect to areas 408, 406 of the image bearing member 206 to provide appropriate charging.
Referring now to
Referring now to
Accordingly, in one embodiment, passive mechanisms (e.g., drive rollers 504, 508, members 506) may be configured to selectively control the first and second charge rollers 402, 404 (
In one embodiment as described above, members 506 may be configured via varied contour paths to enable the primary charge roller 402 to charge only region 408 of the image bearing member 206. Members 506 may also be configured to enable the secondary charge roller 404 to charge only region 406 of the image bearing member 206.
In the exemplary illustration of
Referring to
In the exemplary illustration of
Accordingly, size (e.g., diameter) of the drive members 504, 508 may be varied to provide predetermined positioning of rollers 402, 404 with respect to regions 408, 406. In another embodiment, positions of members 506 of the image bearing member 206 are desired to be of circular shape as other processes (e.g., developing, fixing, etc.) of the hard imaging device 100 (
Referring to
In the exemplary embodiment of
Continuing to refer to the exemplary embodiment shown in
Processing circuitry 302 (
In one example, primary charge roller 402 is controlled to charge region 408 and be insulated from charging of region 406. The secondary charge roller 404 may be configured to charge region 406 and be insulated from region 408. Movement of charge rollers 402, 404 to charge areas 408, 406, respectively, may be controlled using actuator 510 responsive to control of processing circuitry 302 in one embodiment.
Processing circuitry 302 may be configured to issue command signals to actuator 510 to control movement of primary and/or secondary rollers 402, 404, respectively, as described above (e.g., responsive to monitoring rotation of image bearing member 206) or using other control.
Exemplary advantages of some embodiments include providing a clearance between charge rollers and an image bearing member to reduce chances of damage to the charge rollers due to contact with the image bearing member. Since no direct charging of the image bearing member occurs in embodiments having a clearance between the charge rollers and the image bearing member, high charging uniformity in both in-scan and cross-scan directions may be possible. Solutions provided by some embodiments provide a charging system which is more robust to misalignments and material defects during manufacturing. Other advantages of using charge rollers to charge a image bearing member include efficiencies related to cost, size, and Ozone generation rate.
As described herein, some exemplary hard imaging device embodiments utilize image bearing members having a seam area. For hard imaging devices comprising liquid electrophotography systems, it may be desired to charge the seam area to prevent or reduce ink development in the seam area. Usage of a plurality of charge rollers, one dedicated to charge the seam area as described in some embodiments herein, facilitates filtering of contamination materials, such as imaging oil, and reduces the introduction of the contamination materials into the image area of the image bearing member.
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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