Patent Application
20080131163
The present disclosure relates to a customer replaceable unit (CRU) of a sheet handling machine such as an electrostatographic machine, and more particularly concerns a device for preventing undesirable deformations, after assembly, in either roll of a two roll sheet feeding nip assembly for example the retard and feed rolls of a document feeder CRU, during storage and shipping, but before installation of the sheet feeding nip assembly or CRU in the machine.
In a typical electrostatographic printing machine using the xerographic 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 placed manually on a platen of the machine or automatically fed onto such platen by a document handler of the machine. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. This records an electrostatic latent image 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 in a timed manner to a copy sheet fed from a sheet supply. The toner powder image on the copy sheet is subsequently heated to permanently affix it to the copy sheet.
In electrostatographic printing machines such as those described above, the components of the document handler for example, which includes a retard roll and a feed roll as components, can be assembled as a CRU or customer replaceable unit that can be replaced by a customer at the end of life or at the premature failure of one or more of the components. The CRU concept integrates various subsystems whose useful lives are predetermined to be generally the same length. The service replacement interval of the CRU insures maximum reliability and greatly minimizes unscheduled maintenance service calls. Utilization of such a strategy, allows customers to participate in the maintenance and service of their copiers/printers. CRUs insure maximum up time of copiers and minimize downtime and service cost due to end of life or premature failures.
In a sheet feeding document handler, for example, a Duplexing Automatic Document Handler or DADH device, the first roller 212 is a retard roll and the second roller 214 is a feed roll as such rolls are well known in the art. When initially assembled, and in order to function properly, the retard roll and feed roll of each DADH/CRU are designed to contact each other in the CRU. It has been found that during initial warehousing and/or through shipping to a customer site for set up and operation, tread lines and/or flat spots are undesirably formed for example on the retard roll in the area of contact between the two rolls. Such tread lines and/or flat-spots are believed to be the cause of early retard roll flat spotting and of roll noise during operation, in either case resulting in premature failure.
In accordance to the present disclosure, a customer replaceable unit (CRU) assembly is provided for mounting in a sheet handling machine and includes (a) a CRU frame having a frame size for fitting into a mounting portion within the sheet handling machine; (b) a first roller assembled rotatably to the CRU frame; (c) a second roller assembled rotatably to the CRU frame and for resilient contact with the first roller to form a sheet handling nip; and (d) a spacer and anti-mounting assembly including (i) a holding means formed in the CRU frame and (ii) a removable member mounted in the holding means for temporarily preventing mounting of the CRU frame into the mounting portion within the sheet handling machine, and for temporarily spacing the second roller out of resilient contact with the first roller so as to prevent roller flat spots, operating roller noise, and premature roller failure.
Referring now to
Referring now to all the
The CRU frame 202 includes the forked member 204 having the first set of hands 206 for supporting the first roller 212 and a second set of hands 208 for supporting the second roller 214. As illustrated clearly in
The removable member 230 has a member size MS (
The holding means 222 comprise a distendable recess 224 on each side of the width of the frame 202 that is formed in a forked member 204 of the CRU frame between a hand 206 (of first set of hands) and a hand 208 (of the second set of hands). The distendable recess 224 for example may have a generally upside down cross-shape cross-section as shown in
The present disclosure thus is directed to a CRU assembly that includes a specially designed spacer and anti-mounting assembly 220. The anti-mounting assembly 220 includes a disposable, removable member 230 such as a shaft cam device, that when assembled into a distendable feature of the CRU frame, alters or bends the frame of the CRU outwardly so as to separate and prevent the first and second rollers 212, 214, from contacting each other.
The removable member 230 can be made of a plastic or other suitable material. The spacer and anti-mounting assembly 220 including the disposable, removable member 230 will be assembled for such use along with other CRU spares during shipping and storage of the CRU assembly 200, and will be removed, disassembled or modified at the customer site before mounting of the CRU assembly 200 into the sheet handling machine 100. The spacer and anti-mounting assembly 220 is such that when the disposable removable member 230 is removed, disassembled or modified as above, the sheet feeding nip assembly or CRU frame 202 and the retard and feed rollers 212, 214 will return to their manufactured or nip forming starting geometry that has substantially its critical operating dimensions and specifications that are free of clearance and interference issues with other related machine components.
The spacer and anti-mounting assembly 220 is designed so that the customer can easily remove or alter the removable member 230 from the sheet feeding nip assembly or CRU assembly 200 without interfering with either of the first and the second rollers 212, 214. As pointed out above, the member size MS of the removable member 230 is significantly greater than the width CW of the cavity 120, such that the CRU assembly 200 cannot be installed or mounted into its intended portion within the sheet handling machine without first disassembling or removing the removable member 230 from the CRU or CRU assembly. The member size MS for example is a length of the shaft cam device 230 as shown in
As described above, the removable member 230 is a shaft cam device that includes two sets of tabs 234, 236 that can be moved from a free and unloaded vertical orientation (
As can be seen, there has been provided a customer replaceable unit (CRU) assembly for mounting in a sheet handling machine is disclosed and includes (a) a CRU frame having a frame size for fitting into a mounting portion within the sheet handling machine; (b) a first roller assembled rotatably to the CRU frame; (c) a second roller assembled rotatably to the CRU frame and for resilient contact with the first roller to form a sheet handling nip; and (d) a spacer and anti-mounting assembly including (i) a holding means formed in the CRU frame and (ii) a removable member mounted in the holding means for temporarily preventing mounting of the CRU frame into the mounting portion within the sheet handling machine, and for temporarily spacing the second roller out of resilient contact with the first roller so as to prevent roller flat spots, operating roller noise, and premature roller failure.
It will be appreciated that various adaptations of the above-disclosed and other features and functions of this embodiment, or alternatives thereof, may be desirably combined into other different systems or applications. Therefore, unless specifically defined in a specific claim itself, steps or components of the invention should not be implied or imported from any above example as limitations to any particular order, number, position, size, shape, angle, color, or material. Additionally, it be appreciated that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims:
