Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2000-10-20
2001-10-16
Goodrow, John (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S060000, C430S069000
Reexamination Certificate
active
06303254
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to flexible electrostatographic imaging belt members and, more specifically, to imaging belts having mechanically robust outer exposed layers that possess, for example, anti-curl backing layers or ground strip layers with enhanced wear resistance and optical transparency properties.
Flexible electrophotographic imaging members are well known in the art. Typical electrostatographic flexible imaging members include, for example, photosensitive members, such as photoreceptors, commonly utilized in electrophotographic, such as xerographic processes and electroreceptors, and ionographic imaging members for electrographic imaging systems. The flexible electrostatographic imaging members may be seamless or seamed belts. Typical electrophotographic imaging member belts comprise an imaging layer which is a charge transport layer and a charge generating layer on one side of a supporting substrate layer and an anti-curl backing layer coated on the opposite side of the substrate layer. A typical electrographic imaging member belt comprises a dielectric imaging layer on one side of a supporting substrate and an anti-curl backing layer on the opposite side of the substrate. A typical flexible electrostatographic imaging member belt has a ground strip coated near one edge of the belt and adjacent to the imaging layer.
Flexible electrophotographic imaging belt members may comprise a photoconductive layer comprising a single layer or composite layers. One type of composite photoconductive layer used in electrophotography is illustrated in U.S. Pat. No. 4,265,990, which describes a photosensitive member having at least two electrically operative layers. One layer comprises a photoconductive layer which is capable of photogenerating holes and injecting the photogenerated holes into a contiguous charge transport layer. Generally, where the two electrically operative layers are supported on a conductive layer with the photoconductive layer sandwiched between the contiguous charge transport layer and the conductive layer, the outer surface of the charge transport layer is normally charged with a uniform charge of a negative polarity and the supporting electrode is utilized as an anode. The supporting electrode may still function as an anode when the charge transport layer is sandwiched between the supporting electrode and the photoconductive layer. The charge transport layer in this latter embodiment must be capable of supporting the injection of photogenerated electrons from the photoconductive layer and transporting the electrons through the charge transport layer. Photosensitive members having at least two electrically operative layers, as disclosed above, provide excellent electrostatic latent images when charged with a uniform negative electrostatic charge, exposed to a light image and then developed with finely divided electroscopic marking particles. The resulting toner image is usually transferred to a suitable receiving member such as paper.
As more advanced, higher speed electrophotographic copiers, duplicators and printers were developed, degradation of image quality was encountered during extended cycling. Moreover, complex, highly sophisticated duplicating and printing systems operating at very high speeds have placed stringent requirements including narrow operating limits on photoreceptors. For electrophotographic imaging members having a belt configuration, the numerous layers found in modem photoconductive imaging members must be highly flexible, adhere well to adjacent layers, and exhibit predictable electrical characteristics within narrow operating limits to provide excellent toner images over many thousands of cycles. One type of multi-layered photoreceptor that has been employed as a belt in electrophotographic imaging systems comprises a substrate, a conductive layer, a blocking layer, an adhesive layer, a charge generating layer, a charge transport layer, and a conductive ground strip layer adjacent to one edge of the imaging layers. This photoreceptor belt may also comprise additional layers such as an anti-curl backing layer to achieve the desired belt flatness. An optional overcoating layer over the charge transport layer may be used for additional wear, environmental, and chemical protection.
In a machine service environment, a flexible imaging member belt, mounted on a belt supporting module, is generally exposed to repetitive electrophotographic image cycling which subjects the exposed anti-curl backing layer to abrasion due to mechanical fatigue and interaction with the belt drives and other support rollers as well as sliding contact with backer bars. This repetitive cycling leads to a gradual deterioration in the physical/mechanical integrity of the exposed anti-curl backing layer. When the anti-curl layer is worn the thickness thereof is reduced and the anti-curl backing layer experiences a loss of ability to counteract the tendency of imaging members to curl upwardly thereby leading to belt curl. Moreover, uneven wear of the anti-curl backing layer has been found to cause early development of belt ripples which are ultimately manifested as copy printout defects. Thus, the anti-curl backing layer wear that results from mechanical contact interaction during dynamic imaging operations is a significant problem that shortens the service life of the belt and adversely affects image quality.
When a production web stock of several thousand feet of coated multi-layered photoreceptor is rolled up, the charge transport layer and the anti-curl layer are in intimate contact. The high surface contact friction of the charge transport layer against the anti-curl layer causes dimples and creases to develop in the internal layers of the photoreceptor. Since these physically induced defects manifest themselves as print defects in xerographic copies, the unacceptable segments of this photoreceptor web stock are discarded thereby decreasing production yield. Although attempts have been made to overcome these problems, the solution of one problem often leads to the generation of additional problems.
Flexible photoreceptor belts are fabricated from sheets cut from an electrophotographic imaging member web stock. The cut sheets are generally rectangular in shape. All edges may be of the same length or one pair of parallel edges may be longer than the other pair of parallel edges. The sheet is formed into a belt by joining the overlapping opposite marginal end regions of the sheet. A seam is typically produced in the overlapping opposite marginal end regions at the point of joining. Joining may be effected in any suitable manner, such as welding including for example ultrasonic processes, gluing, taping, pressure/heat fusing, and the like methods. However, ultrasonic seam welding is generally the preferred method of joining because it is rapid, clean, generally free of solvent application, and produces a thin and narrow seam. The ultrasonic seam welding process involves a mechanical pounding action of a welding horn which generate a sufficient amount of heat energy at the contiguous overlapping marginal end regions of the imaging member sheet to maximize melting of one or more layers therein. A typical ultrasonic welding process is carried out by holding down the overlapping ends of the flexible imaging member sheet with vacuum onto a flat anvil and guiding the flat end of the ultrasonic vibrating horn transversely across the width of the sheet and directly over the overlapped junction to form a welded seam having two adjacent seam splashings consisting of the molten mass of the imaging member layers ejected to the either side of the welded overlapped seam. These seam splashings of the ejected molten mass comprise about 40 percent by weight of anti-curl layer material. The splashings can include hard crystalline materials and have a rough abrasive outer surface which abrades the photoreceptor cleaning blade during dynamic image cycling causing the blade to lose cleaning efficiency and shortens blade service life.
Alteration of mate
Street Terry L.
Wagner Moritz P.
Yu Robert C. U.
Goodrow John
Haack John L.
Xerox Corporation
LandOfFree
Electrostatographic imaging member does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrostatographic imaging member, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrostatographic imaging member will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2597603