Patent Application
20120033991
The present invention relates to electrophotography in general, and in particular to a replacement cartridge for an electrophotographic printer.
Electrophotographic equipment utilizes sensitive components that must be routinely serviced by either dedicated service personnel or by the end user. Many of these components are easily damaged unless care is exercised during replacement. In some instances, it is considered imprudent to depend upon an individual exercising care as a step in carrying out critical operation. This is especially important when the risk of error is high, and the cost and machine down-time associated with error is great.
A primary component requiring frequent replacement within an electrophotographic print engine is the photoreceptive member. The function of the photoconductor is to provide a means of developing an image and transferring that image to paper. The photoreceptive member is coated with photosensitive material which is essential to operation of electrographic printers. The photosensitive material is easily scratched and can be damaged by exposure to ambient light if handled imprudently. This type of damage creates unacceptable image quality defects in the transferred image.
In close proximity to the receptive member are many components that support the imaging of the photoconductor. These components can scratch or abrade the photoreceptive member during replacement. There is a need to eliminate the potential for damage to the photoreceptive member.
Briefly, according to one aspect of the present invention an in situ replacement cartridge for an electrophotographic printer includes a rigid, cylindrical photoreceptive member; a housing for retaining and attaching the photoreceptive member to the printer; and a removable shield surrounding the photoreceptive member.
The invention and its objects and advantages will become more apparent in the detailed description of the preferred embodiment presented below.
An electrophotographic printer includes all components necessary to accomplish the task of printing an image on paper. A printer is comprised of various subassemblies which perform specific functions.
An imaging module in the printer consists of components to enable printing of a single color image. Multiple modules may be assembled to enable the printing of multiple color images.
Primary charging subsystem 210 uniformly electrostatically charges photoreceptor 206 of photoreceptive member 111, shown in the form of an imaging cylinder. Charging subsystem 210 may include a grid 213 having a selected voltage, or may be in the form of a roller with conductive properties.
Additional necessary components provided for control may be assembled around the various process elements of the respective printing modules. Meter 211 measures the uniform electrostatic charge provided by charging subsystem 210, and meter 212 measures the post-exposure surface potential within a patch area of a latent image formed from time to time in a non-image area on photoreceptive member 206.
Image writer 220 is used to expose photoreceptive member 206 and may be a light emitting diode (LED) array or other similar mechanisms or laser. Toning unit 225, comprising elements 226 and 227 is used to develop the latent image created by image writer 220 on photoreceptive member 206. Cleaning unit 230 removes residual toner from photoreceptive member 206 after transfer of the image to secondary receiver (not shown). Other meters and components may be included.
Within the imaging module 31, periodic replacement of critical components is necessary to ensure proper function. It may be desired to cluster multiple components to enable simultaneous replacement.
Referring to
Because of the proximity of subsystems that interface with module 31 and with replacement cartridge 200, it is necessary to have large areas of the photoreceptive member open during use. During insertion into the print engine, these open, unprotected areas could be damaged either mechanically or by light exposure. Therefore it is necessary to protect the photoreceptive member 206 from damage, either from extraneous light, fingerprints, or mechanical scrapes. The protective guards 231a and 231b, also referred to as a removable shield, slide in place in grooves within the replacement cartridge housing. These removable shields 231a and 231b stay in place when the cartridge is installed in the printer, and are removed by sliding out of the housing to the front of the equipment after the replacement cartridge 200 is in place in the printer.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention.
Reference is made to commonly-assigned copending U.S. patent application Ser. No. ______ (Attorney Docket No. 96470/NAB), filed herewith, entitled METHOD OF PREVENTING DAMAGE TO A PHOTOCONDUCTOR, by Pitas et al.; the disclosure of which is incorporated herein.
