Printing system

A printing system and method is provided. The printing system includes one or more printing system modules, at least one media sheet path interfacing the printing system modules, and a job scheduler for executing one or more printing system print jobs. The job scheduler routes a media sheet to one or more printing system modules for preshrinking or preenlarging without marking and subsequently routes the preshrunk or preenlarged media sheet to one or more printing system modules for marking. The method of printing includes generating a print job to be printed using one or more printing system modules. Print jobs requiring two or more printing system modules for marking are executed by routing a media sheet to one or more printing system modules for preshrinking or preenlarging without marking, and subsequently routing the preshrunk or preenlarged media sheet to the one or more printing modules for marking.

BACKGROUND

The present disclosure relates to preshrinking and preenlarging of sheets for improved image registration as applied to printing systems. It finds particular application in conjunction with overlay printing and integrated printing modules consisting of several marking engines, each having the same or different printing capabilities, and will be described with particular reference thereto. However, it is to be appreciated that the present disclosure is also amenable to other like applications.

Overlay printing is a printing method whereby a first marking engine prints content on one side of a sheet, and then a second marking engine with different capability prints complimentary content on the same side. In fact, it is possible that monochrome content, CMYK 4-color content, and custom color content could all be desired on the same side of a sheet, such that a given sheet passes through three different marking engines. When consecutively marking a sheet using multiple marking engines, the need to properly register the image content from the different marking engines becomes a factor which affects the overall quality of the printed sheet and ultimately customer satisfaction. The accuracy of registering a sheet for subsequent making can be a function of many systems, including but not limited to sheet control, sheet dimension stability and/or predictability, marking engine control, etc.

This disclosure relates to sheet dimension stability; specifically, the shrinkage or enlargement of a media sheet as it passes through a marking engine. As a sheet is passed through a first marking engine for image marking, the sheet will shrink or enlarge and thereby cause a second marking of the sheet to be misaligned. The third marking of the sheet will also be misaligned as a function of the amount the sheet shrinks or enlarges during the first and second markings. As the sheet passes through subsequent marking engines, additional sheet registration error will occur as a result of the shrinkage or enlargement of the sheet through each marking engine. Depending on the cumulative amount of shrinkage or enlargement, the finished overlay printed sheet can have a noticeable registration misalignment of images and create a lower degree of customer satisfaction with the finished product. This disclosure provides a way to compensate for the cumulative media shrinkage or enlargement discussed heretofore by sending a sheet initially through one or more non-printing cycles before commencing one or marking operations.

CROSS REFERENCE TO RELATED PATENTS AND APPLICATIONS

The following applications, the disclosures of each being totally incorporated herein by reference are mentioned:

U.S. Provisional Application Ser. No. 60/631,651, filed Nov. 30, 2004, entitled “TIGHTLY INTEGRATED PARALLEL PRINTING ARCHITECTURE MAKING USE OF COMBINED COLOR AND MONOCHROME ENGINES,” by David G. Anderson, et al.;

U.S. Provisional Patent Application Ser. No. 60/631,918, filed Nov. 30, 2004, entitled “PRINTING SYSTEM WITH MULTIPLE OPERATIONS FOR FINAL APPEARANCE AND PERMANENCE,” by David G. Anderson et al.;

U.S. Provisional Patent Application Ser. No. 60/631,921, filed Nov. 30, 2004, entitled “PRINTING SYSTEM WITH MULTIPLE OPERATIONS FOR FINAL APPEARANCE AND PERMANENCE,” by David G. Anderson et al.;

U.S. application Ser. No. 10/953,953, filed Sep. 29, 2004, entitled “CUSTOMIZED SET POINT CONTROL FOR OUTPUT STABILITY IN A TIPP ARCHITECTURE,” by Charles A. Radulski et al.;

U.S. application Ser. No. 11/090,502, filed Mar. 25, 2005, entitled IMAGE QUALITY CONTROL METHOD AND APPARATUS FOR MULTIPLE MARKING ENGINE SYSTEMS,” by Michael C. Mongeon;

BRIEF DESCRIPTION

Aspects of the present disclosure and embodiments thereof include a printing system and method. In one aspect of the disclosure, a printing system is provided including at least two printing system modules; at least one media sheet path interfacing the printing system modules; and a job scheduler for executing one or more printing system print jobs, the job scheduler routing a media sheet to one or more printing system modules for preshrinking or preenlarging without marking and subsequently routing the preshrunk or preenlarged media sheet to one or more printing system modules for marking.

Another aspect includes a method of printing. The method includes generating a print job to be printed using at one printing system module, and analyzing the image content of the print job and determining if the print job requires a media sheet to be marked using two or more printing system modules or the print job requires a media sheet to be marked using only one printing system module. Print jobs requiring two or more printing system modules for marking are executed by routing a media sheet to one or more printing system modules for preshrinking or preenlarging without marking, and subsequently routing the preshrunk or preenlarged media sheet to the one or more printing modules for marking. Print jobs requiring only one printing system module for marking, are executed by routing a media sheet to a printing module for marking.

Another aspect of the disclosure includes a xerographic system. The xerographic system including a media sheet feeder module and a plurality of horizontally and vertically integrated marking devices for applying images to print media. The plurality of marking engines includes a black and white marking engine, a color marking engine, and a marking engine and/or a fuser without a marking engine. A media sheet path includes a lower highway and/or an upper highway, and a return highway. The highways are integrated with the plurality of integrated marking devices, a feeder module, and a finisher module. A job scheduler executes one or more printing system print jobs, the job scheduler capable of routing a media sheet to one or more printing system modules for preshrinking or preenlarging without marking and subsequently routing the preshrunk or preenlarged media sheet to one or more printing system modules for marking. Print jobs having sheets requiring black and white printing, and color printing include a media sheet preshrinking or preenlarging process. The media sheet preshrinking or preenlarging process routes a media sheet from the sheet feeder module to a printing system module for processing the media sheet without marking. Subsequently, the preshrunk or preenlarged media sheet is routed to a printing system module for black and white marking. The media sheet is subsequently routed to another printing system module for color marking. After printing is completed the media sheet is routed to the finisher module. As an alternative, the media sheet can be routed to a color painting system module for color marking, and subsequently to a black and white printing module for black and white marking.

DETAILED DESCRIPTION

Printing systems including multiple xerographic marking engines have the ability to print images on one or two sides of a sheet using multiple image marking engines. The process of overlay printing is sensitive to the accurate registration of the media sheet as it is marked by multiple image marking engines. A significant factor affecting the media sheet registration, relative to multiple marking engines, is the dimensional stability of the media sheet as it is processed through the multiple image marking engines.

The detailed description which follows describes a printing system which preshrinks media sheets prior to subsequent image marking for improved image registration. The exemplary embodiments described relate to the media sheets that shrink as they pass through an image marking engine or fuser. However, the exemplary embodiments described are equally applicable to media sheets that enlarge as they pass through an image marking engine or fuser.

With reference toFIG. 1, illustrated is a printing fixture2used to determine the amount of media sheet shrinkage associated with each pass of a sheet through a marking engine. As illustrated, the printing fixture2includes a cyclical sheet path4, this sheet path including an initial sheet feed6, a pressure roll8, a transfuse nip10, a heated fuser roll12and a sheet path14.FIG. 2,FIG. 3A,FIG. 3B,FIG. 4A,FIG. 4B,FIG. 5AandFIG. 5Bgraphically represent shrinkage data obtained from the print fixture illustrated inFIG. 1.

To obtain media sheet shrinkage data, a paper sheet was fed into the sheet feed6and routed through the transfuse nip10. The transfuse nip10includes a pressure roll8and a heated fuser roll12. After passing through the transfuse nip10, the paper sheet traveled along the sheet path4indicated inFIG. 1and was cycled through the transfuse nip10a second time. This cycle was repeated several times to obtain media sheet length and width dimensional changes as a function of passes through the transfuse nip10at a given temperature, pressure as applied by the pressure roll8and process speed.

The graphical illustrations of media sheet shrinkage as a function of transfuse nip passes establish that a majority of the cumulative media shrinkage can be compensated by routing a media sheet initially through one or more non-printing marking engines and subsequently marking the media sheet with a plurality of marking engines.

FIG. 2illustrates very little change of the length20and width22dimensions of a paper sheet with a transfuse nip temperature of 25° C. and transfuse pressure of 55 ps. However, as the transfuse temperature is increased while maintaining a constant transfuse nip pressure and process speed, the length and width dimensions of the paper sheet decrease with each successive pass through the transfuse nip.FIG. 3AandFIG. 3Billustrate the length and width dimensional changes, respectively, of paper sheets30,32,34,36,38,40,42,44,46and48with a transfuse nip temperature of 80° C.FIG. 4AandFIG. 4Billustrate the dimensional length and width changes, respectively, of paper sheets50,52,54,56,58,60,62,64,6-6and68with a transfuse nip temperature of 100° C.FIG. 5AandFIG. 5Billustrate the length and width dimensional changes, respectively, of paper sheets70,72,74,76,78,80,82,84,86and88with a transfuse nip temperature of 125° C.

In addition to the discussion heretofore, the graphs ofFIG. 3A,FIG. 3B,FIG. 4A,FIG. 4B,FIG. 5AandFIG. 5Billustrate after the first 5-6 passes through the fuser nip, little or no subsequent media sheet shrinkage occurs. This is most likely because the sheet moisture content has reached its minimum steady state value given the ambient relative humidity.

ReferencingFIG. 5AandFIG. 5B, approximately 80% of total media sheet shrinkage occurs during the initial 1-2 passes through a fusing system. Therefore, if the total shrinkage is approximately 1 mm, as illustrated inFIG. 5AandFIG. 5B, with multiple passes through a fuser, 0.8 mm of shrinkage will occur during the media sheets initial 1-2 passes or preshrinking process, and 0.2 mm will be seen as a residual alignment error between various content planes associated with the overlay marking after the preshrinking process is completed. This 0.2 mm error has been determined to be acceptable print quality.

Those of skill in the art will appreciate other combinations of preshrinking process passes through the fusing nip of a non-printing marking engine before routing the preshrunk media sheet to a series of marking engines for overlay printing. The greater the number of preshrinking passes through the fusing nip, the smaller the amount of registration error during the subsequent image marking processes because the dimensional stability of the media sheet increase. However, the lesser the amount of preshrinking passes through the fusing nip, the greater the process efficiency of the overall printing system.

With reference toFIGS. 6-10, exemplary embodiments of the present disclosure will be described. With reference toFIG. 6, illustrated is a printing system including a media sheet feeder module90, a plurality of horizontally and vertically integrated marking devices92,94,96,98,100, and102, a finisher module104and a media sheet path including an upper highway106, a lower highway108and a return path110. In addition, an input transport module112and an output transport module114integrate the feeder module90and finisher module104, respectively, to the media sheet path structure. The printing system is connected to a data source (not shown) which provides print job data and controls the execution of print jobs. In addition, a job scheduler module (not shown) provides the necessary control to select which printing system modules will be utilized for a particular print job.

To provide printing flexibility and overlay printing ability, the exemplary embodiment ofFIG. 6includes color image marking engines94and100, black and white image marking engines92and98, a MICR image marking engine102and a custom color image marking engine96.

ReferencingFIG. 7, a detailed method of operating the embodiment ofFIG. 6is explained.FIG. 7illustrates the flow chart of an overlay printing job which includes black text and a custom color logo. The initial print job data is transmitted to the printing system by a network, pc, cd, or other computer readable medium or device. The job scheduler analyzes the image content of the incoming print job120to determine if multiple image marking engines are required to complete the print job. In this example, a black text document with custom color is detected122Subsequently, the job scheduler schedules124and allocates126a black and white text marking engine92and a custom color marking engine96to perform the simplex overprint job124. The job scheduler next selects unused black text printing module K298for preprinting or preshrinking passes128. It is to be understood that the job scheduler could have selected any unused printing module, (i.e., image marking engine, fuser, etc.) to perform the preprinting pass. After the job scheduler has allocated the proper printing modules to complete the job, the media sheet feeder feeds the required sheets into the printing system130. Sheets are routed through the input transport module to the lower highway132and routed to printing module K298media sheet input for preshrinking134within printing module K2, which includes a fuser. After passing through the fuser, the media object will be shrunk approximately 60%134of the total shrinkage potential. Next, the media sheet is routed from the media sheet output of printing module K2along the lower highway and re-circulated back along the return highway136. Subsequently, the media sheet is routed along the upper highway to printing module K1for black text printing138. After the sheet passes through the black text image marking engine K1, the sheet will be shrunk approximately 80% of the total shrinkage potential. Next, the sheet is routed through the custom color printing module CC for logo printing140. Total shrinkage of the media sheet is approximately 90% of total shrinkage potential after printing has been completed. In addition, the media sheet only shrinks approximately 20% after the black text is marked on the sheet and a subsequent custom color is marked on the sheet. The net effect of this process is a reduction of mis-registration error relative to the images printed on the media sheet. Subsequent to image marking by printing module CC, the media sheet is routed to the output transport module by the upper highway and from the output transport module to the finisher module142.

ReferencingFIG. 8, another detailed method of operating the embodiment ofFIG. 6will be explained.FIG. 8illustrates the flow chart of an overlay printing job which includes black text and a custom color logo. The initial print job data is transmitted to the printing system by a network, pc, cd, or other computer readable medium or device. The job scheduler analyzes the image content of the incoming print job150to determine if multiple image marking engines are required to complete the print job. In this example, a black text document with custom color is detected152. Subsequently, the job scheduler schedules154and allocates a black text marking engine K1and a custom color marking engine CC156to perform the simplex overlay print job. The job scheduler next selects unused printing modules K2and C2for preprinting or preshrinking passes158. It is to be understood that the job scheduler can select any unused printing module (i.e., image marking engine, fuser, etc.) to perform the preprinting passes. After the job scheduler has allocated the proper printing modules to complete the job, the media sheet feeder feeds the required sheets into the printing system160. Sheets are routed through the input transport module to the lower highway162which routes the media sheets to printing modules K2and C2, respectively, for preprinting passes164. After the media sheet has passed through the fuser of printing module K2and C2, the media sheet will be shrunk approximately 80% of the total shrinkage potential. Next, the media sheet is routed from the media sheet output of printing module C2along the lower highway and re-circulated back along the return highway166. Subsequently, the media sheet is routed along the upper highway to printing module K1for black test printing168. After the sheet passes through the black text image marking engine K1, the sheet will be shrunk approximately 90% of the total shrinkage potential. Next, the sheet is routed through the custom color printing module CC for logo printing172. Total shrinkage of the media sheet is approximately 100% of total shrinkage potential after printing has been completed. In addition, the media sheet only shrinks approximately 10% during the custom color logo marking process. The net effect of this process is a reduction of mis-registration error relative to the images printed on the media sheet. Subsequent to image marking by printing module CC, the media sheet is routed to the output transport module by the upper highway and from the output transport module to the finisher module172.

FIG. 9illustrates another exemplary embodiment of this disclosure. The embodiment includes fuser modules F1180and F2182in addition to the integrated printing modules described with reference toFIG. 6.

ReferencingFIG. 10, a detailed method of operating the embodiment ofFIG. 9is described.FIG. 10illustrates the flow chart of an overlay printing job which includes black and a custom color logo. The initial print job data is transmitted to the printing system by a network, pc, cd or other computer readable media or device. The job scheduler analyzes the image content of the incoming print job to determine if multiple image marking engines are required190to complete the print job. In this example, a black text document with custom color is detected192. Subsequently, the job scheduler schedules194and allocates196a black text marking engine K1and a custom color marking engine CC to perform the simplex overlay print job. The job scheduler next selects198unused fuser F2for preprinting or preshrinking passes. It is to be understood that the job scheduler can select any unused printing module (i.e., marking engine, fuser, etc.) to perform the preprinting passes. After the job scheduler has allocated the proper printing modules to complete the job, the media sheet feeder feeds200the required sheets into the printing system. Sheets are routed through the input transport module to the lower highway202which routes the media sheets to fuser F2for preprinting passes204. After the media sheet has passed through fuser F2, the media sheet will be shrunk approximately 60% of the total shrinkage potential. Next, the media sheet is routed from the media sheet output of the fuser module F2along with return highway to the upper highway206. Subsequently, the media sheet is routed along the upper highway to printing module K1for black text printing208. After the sheet passes through the black text image marking engine K1, the sheet will be shrunk approximately 80% of the total shrinkage potential. Next, the sheet is routed through the custom color printing module CC for logo printing210. Total shrinkage of the media sheet is approximately 90% of total shrinkage potential after printing has been completed. In addition, the media sheet only shrinks approximately 10% during the custom color logo marking process. The net effect of the process described with reference toFIG. 10is a reduction of mis-registration error relative to the images printed on the media sheet. Subsequent to image marking by printing module CC the media sheet is routed to the output transport module by the upper highway and from the output transport module to the finisher module212.