Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2000-10-31
2001-08-21
Dote, Janis L. (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S127000, C430S130000, C430S069000, C156S073400, C156S189000, C156S266000, C156S304600
Reexamination Certificate
active
06277534
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to electrostatographic imaging members.
2. Description of Related Art
Flexible electrostatographic imaging members include, for example, electrophotographic imaging members or photoreceptors for electrophotographic imaging systems, and electroreceptors or ionographic imaging members for electrographic imaging systems.
Flexible electrostatographic imaging members include a substrate and layers formed on the substrate. Photographic imaging members or photoreceptors comprise a substrate and a plurality of layers formed on the substrate. Typically, a charge transport layer, a charge generation layer, an adhesive layer and a charge blocking layer are formed on one side of the substrate, and an anti-curl backing layer is formed on the opposite side of the substrate. Electrographic imaging members include a substrate and typically also an electrically conductive layer and an insulative imaging layer formed over the substrate.
The imaging member material or web for forming electrostatographic imaging members is provided in rolls. The rolls are cut into sheets for forming electrostatographic imaging members. The sheets are typically square or rectangular shaped and have various lengths depending on the intended use of the sheets. Prior to cutting the roll into individual sheets, the web is inspected for defects by a detecting device, such as a light-emitting scanner. The scanner scans the web for the presence of internal defects and/or surface defects. The defects may be small or large internal or surface defects. For example, small internal defects can be random, which large surface defects, such as coating defects, can extend over the entire length of the web.
SUMMARY OF THE INVENTION
In order to form defect-free electrostatographic imaging members that include only one seam, the roll must contain continuous lengths of the web that have a length equal to at least the desired length of the electrostatographic imaging member. The defect-free portions of the web having the desired length are identified by inspection and then cut from the roll in the form of sheets. The defect-free sheets that are cut from the roll are then formed into belts or other configurations. The belts are commonly formed by overlapping the opposed ends of the sheet and forming a joint to secure the opposite ends together. The joints can be formed, for example, by ultrasonic welding techniques. Ultrasonic welding operations form a seam “splash” adjacent to either side of the overlapping joint of the seam. The splash consists of a molten mixture of the materials forming the layers on the substrate.
The remainder of the roll of the web that includes defects, or that is free of defects but is too short to individually form a single-seam belt, has previously been discarded as waste material. Due to the cost of the web, this waste material constitutes a significant economic loss. Accordingly, there is a need for electrostatographic imaging members and processes of making these members that can use this material that would otherwise be wasted.
Another problem associated with known electrostatographic imaging members such as photoreceptor belts is cracking and/or delamination at the welded seams. This problem has become more important in more advanced, higher speed electrophotographic imagers that include a flexible belt. It has been found that in these imagers, cracking and/or delamination at the welded seam frequently occurs during electrophotographic imaging and/or cleaning belt cycling processes. Premature cracking of the charge transport layer has also been a problem in known imagers. Cracks that develop in the photoreceptor transport layer cause print defects in the final copy and therefore shorten the belt's targeted service life. Cracking and/or delamination at the seam creates deposition sites at which debris can collect and also adversely affects cleaning of the belt.
Under dynamic fatigue loading conditions existing in electrophotographic imagers, the junction where the splash edge meets the charge transport layer surface provides a focal point for stress concentration and becomes a point of mechanical integrity failure in the photoreceptor belt. Dynamic fatigue at this stress concentration point facilitates tear initiation through the charge transport layer to form a vertical crack. This crack then propagates horizontally through the weak charge generating layer/adhesive layer interface bond to produce local seam delamination.
In addition, in known photoreceptor belts, seams fabricated by ultrasonic welding have an excessive seam overlap thickness and large splashes, which interfere with cleaning operations, accelerate cleaning blade wear, affect photoreceptor belt motion quality and disturb toner image acoustic transfer assist device operations. Such known photoreceptor belts are also prone to develop charge transport layer cracking and belt ripples.
Known photoreceptors normally include an anti-curl backing layer to counteract curling of the web. However, the anti-curl backing layer can cause problems in fabricated photoreceptor belts. These problems include that known photoreceptor belts contain a substantial amount of built-in internal tensile strain in the charge transport layer due to the counter balancing force exerted by the anti-curl backing layer coating to offset the curl. Belt ripples can form during operation of the belts and prevent uniform contact between receiving sheets and toner images carried on the surface of the photoreceptor belt for complete toner image transfer, thereby adversely affecting the quality of the final copy print-outs. Moreover, belt ripples also can significantly reduce the efficiency of cleaning blade function, which in turn is detrimental to the formation of high quality images in the final print copies.
Photoreceptors having an anti-curl backing layer have also been found to have reduced resistance to the onset of cyclic fatigue charge transport layer cracking during cycling over belt support rollers. Fatigue bending strain over belt support rollers during dynamic photoreceptor belt machine cycling, causes cracking development in the charge transport layer as well as seam cracking/delamination, which shortens the service life of the photoreceptor belt.
Moreover, the anti-curl backing layer also increases the volume of molten mass ejection during the ultrasonic seam welding process of the overlap joint to produce a larger splash.
Although the foregoing description refers in detail to electrophotographic imaging members or photoreceptors, the problems described also can occur in electrographic imaging members.
This invention provides electrostatographic imaging members formed from electrostatographic imaging member material, or web, that prior to this invention was discarded as waste material.
This invention separately provides multiple-seam, electrostatographic imaging members that comprise two or more sheets and also two or more seams at which the sheets are joined together.
This invention separately provides multiple-seam, electrostatographic imaging members that comprise seams located in the imaging member at regions that are not imaged.
This invention separately provides methods of making electrostatographic imaging members from web that prior to this invention was discarded as waste material.
This invention separately provides methods of making electrostatographic imaging members that comprise inspecting a supply of web, identifying defect-free portions of the web that have a length that is less than the length of an electrostatographic imaging member to be formed from the web, and forming an imaging member by joining together at least two of these defect-free web portions.
This invention separately provides methods of forming electrostatographic imaging members comprising two or more sheets of web and two or more seams joining the sheets together.
This invention separately provides methods of forming images using the multiple-seam, electrostatographic imaging members.
This invention sepa
Darcy John J.
Foltz Robert S.
Langlois Edouard E.
Millonzi Richard P.
Yu Robert C. U.
Dote Janis L.
Oliff & Berridg,e PLC
Xerox Corporation
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