Patent Application
20100196072
The following US patent application is incorporated in its entirety for the teachings therein: U.S. Ser. No. 12/262,803, filed Oct. 31, 2008, entitled METHOD OF AND SYSTEM FOR MODULE TO MODULE SKEW ALIGNMENT, assigned to the assignee hereof (Attorney File No. 20080589).
The present disclosure relates to a modular architecture for electrostatographic or xerographic printing systems.
Printer architectures for color xerographic printing are well known. In general, there are provided a number of development units, each development unit contributing to the printing process a toner for a component color of the printed image. In the case of a full-color printing apparatus, there are typically four development units, cyan, magenta, yellow, and black (CMYK). In a “highlight color” printing apparatus, where it desired to print black plus one other predetermined color, a typical arrangement is to have a black development unit and one or more development units, one for each of a selectable set of highlight colors, only one of which would be used at a time. Other types of architecture include “hexachrome,” where there are two additional color development units beyond CMYK, thus providing an extended color gamut for the printer; and arrangements that include a development unit for applying clear toner, or one applying a toner with special properties such as MICR (magnetic ink character recognition) toner.
Examples of typical basic color xerographic architectures are shown in U.S. Pat. Nos. 6,628,909; 7,177,585; and 6,871,037. Variously, the development units could be arranged around a single photoreceptor belt; each development unit could be associated with a single drum photoreceptor, and the drum photoreceptors arranged around a common “intermediate belt” that accumulates the primary-color toner images for transfer to a print sheet; or the drum photoreceptors could each directly transfer their primary-color images to a sheet moving past each photoreceptor. U.S. Pat. No. 6,718,879 and U.S. Patent Application Publication 20010043823 show examples of control systems useful for accurate placement of images in a large color printer.
The present disclosure relates to a modular architecture for xerographic printing, in which separate modules, each providing one type of toner, can be selectably combined and operated for various purposes.
According to one aspect, there is provided a printing apparatus, comprising a plurality of substantially identical modules forming a common sheet path. Each module includes an image receptor, a supply of marking material of a predetermined type, and means for creating an image of marking material on the image receptor. Each module further includes a transport for receiving a sheet, moving the sheet to receive the image from the image receptor, and making the sheet available for printing by a subsequent module in the sheet path. A sheet sensing system detects the position of a sheet received by the transport. A correction module altering the image created by the marking engine based on a signal from the sheet sensing system.
According to another aspect, there is provided a module for use in a printing apparatus. The module includes an image receptor, a supply of marking material of a predetermined type, and means for creating an image of marking material on the image receptor. Each module further includes a transport for receiving a sheet, moving the sheet to receive the image from the image receptor, and making the sheet available for printing by a subsequent module in the sheet path. A sheet sensing system detects the position of a sheet received by the transport. A correction module altering the image created by the marking engine based on a signal from the sheet sensing system.
For instance, if a simple monochrome printer such as 100 is desired, a single module 10, supplied with black toner, is combined with an input module 12 and a fusing module 14, as well as a sheet exit module 16 as needed. Sheet-feeding and finishing modules, such as for stapling or booklet-making, not shown, could be provided as well. As can be seen, the combination of modules “adds up” to a monochrome printing apparatus 100. If a “highlight color” printer is desired, two modules 10, one with black toner and one with the highlight color toner, are provided, forming printer 102. If a “full color” printer is desired, four modules 10, one with black toner and the others with cyan, magenta, and yellow toners respectively, are provided, forming printer 104. Printer 106, having six modules 10, could provide black, cyan, magenta, and yellow toners respectively, along with two additional types of toner for a hexachrome or other special-purpose printer 106. Printer 108 uses a “stack” of two sets of modules 10, along with input modules, fuser modules 14, and sheet exit modules 16, for a high-productivity color printer.
Further within a module 10 is a structure that can be generally called a “transport” 50 for carrying a sheet through the portion of the sheet path corresponding to the module 10. The overall function of transport 50 includes receiving a sheet, moving the sheet through the sheet path to receive a toner image from the photoreceptor 20, and making the sheet available for printing by a subsequent module 10 in the sheet path. In the embodiment, the transport 50 also has the function of bringing a sheet in contact with the photoreceptor 20. Further as shown, the transport 50 in this embodiment includes a single belt, extending the length of the portion of the sheet path corresponding to the module 10. All of the printer hardware for a module 10 is supported by a frame 11, having the function of supporting at least the photoreceptor 10 and the transport 50, the frame 11 being configured for attachment of a prior and a subsequent module to form the common sheet path.
As shown in the
In the illustrated embodiment, the various error signals output by sheet sensing system 60 within each module 10 are collected by what is here called a “correction module,” indicated as 70. The overall function of correction module 70, which incorporates both hardware and software (and can be considered as part of a larger image-processing system which accepts partial image data to be printed by a printing module 10), is to take error signals relating to positional or other abnormalities associated with an incoming print sheet, and cause these anomalies to influence the print engine, ultimately the behavior of a modulating laser or ionographic head in an electrostatographic marking device, or an ink-jet printhead in an ink-jet printing device.
It should be appreciated that any sheet sensing system 60 that can detect the position of incoming media could be used in the present invention and that the present invention is in no way limited to the use of the sensing system shown in this example. A related system is described in U.S. Ser. No. 12/262,803, filed Oct. 31, 2008, entitled METHOD OF AND SYSTEM FOR MODULE TO MODULE SKEW ALIGNMENT, cited above.
Further shown in
In possible implementations, the central processor 80, governing and coordinating a plurality of printing modules 10, can interact with the correction modules 70 within each print module 10. In other words, correction of positional or magnification anomalies among a series of modules along a print path can be divided between the correction module 70 associated with each print module 10 and the central processor 80 controlling the whole print path. In one implementation, anomalies within a predetermined spatial range (smaller than, for example, 0.5 mm) can be corrected internally within each print module 10, while larger or cumulative spatial anomalies are effectively referred to central processor 80, such as for more systemic correction and/or notifying the human user. An example of systemic correction, for any purpose, would include having a marking device in an upstream module 10 along the sheet path move the images it produces in response to a positional anomaly detected in a downstream module 10, as opposed or in addition to a single module 10 making the correction in response to detecting the anomaly on a incoming sheet and performing the correction entirely internally. Another arrangement could provide for the central processor 80 detecting recurrent patterns of positional errors as individual modules are used, and determining a course of action.
Although the illustrated embodiment describes what can be called a “digital” printing system, in that the marking engine, whether electrostatographic, ink-jet, or some other printing technology, ultimately relies on input image data in digital form, certain of the print modules in a larger system may use analog or fixed-image systems, such as offset or flexographic printing. For instance, if it is desired to print a magazine in which only portions of the image data, such as a mailing address, are variable from print to print, and the rest comprising the same partial image for every print, only a subset of all of the modules forming the sheet path need be responsive to digital image data. The non-digital modules could use another technology, such as offset or flexographic.
The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including other marking technologies such ink jet printing and those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
