Print scaling correction mechanism

Abstract

To disclose an art related to image processing in a printing system.SOLUTION: A system includes: at least one physical memory device to store a scaling correction logic; and one or more processors connected with the at least one physical memory device. The one or more processors execute the scaling correction logic to receive first measured print image data associated with test marks printed on a first surface of a print medium based on a print job and second measured print image data associated with test marks printed on the second surface of the print medium, generate a first surface scaling factor on the basis of the first measured print image data and a second surface scaling factor on the basis of the second measured print image data, and generate a scaling factor correction on the basis of the first surface scaling factor and the second surface scaling factor generated.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to the field of printing systems, and more particularly to image processing in printing systems. [Background technology]

[0002] Entities with substantial printing demands typically implement high-speed production printers for volume printing (e.g., 100 pages / minute or more). Production printers may include continuous form printers that print on long webs of print media (such as paper) stored on large rolls. Production printers typically include a localized print controller that controls the overall operation of the printing system and one or more print engines that include one or more print head assemblies, each of which includes an array of print heads. Each print engine can be 3 meters or more in length. Each print head includes many nozzles (e.g., inkjet nozzles) for the ejection of ink or any marking material suitable for printing on the print media. Summary of the Invention

[0003] In one embodiment, the system includes at least one physical memory device that stores scaling correction logic and one or more processors connected to the at least one physical memory device, where the one or more processors execute the scaling correction logic to receive first evaluated printed image data associated with test marks printed on a first side of a printing medium based on a print job and second evaluated printed image data associated with test marks printed on a second side of the printing medium, generate a first surface scaling coefficient based on the first evaluated printed image data, generate a second surface scaling coefficient based on the second evaluated printed image data, and generate a scaling coefficient correction based on the generated first surface scaling coefficient and second surface scaling coefficient. [Brief description of the drawings]

[0004] A better understanding of the invention may be had from the following detailed description taken in conjunction with the following drawings, in which:

[0005] [Figure 1] FIG. 1 is a block diagram of an embodiment of a printing system.

[0006] [Figure 2A] FIG. 2 is a block diagram illustrating an embodiment of a print controller. [Figure 2B] FIG. 2 is a block diagram illustrating an embodiment of a print controller. [Figure 2C] FIG. 2 is a block diagram illustrating an embodiment of a print controller.

[0007] [Diagram 3] 1 illustrates one embodiment of a scaling module.

[0008] [Figure 4A] 1 shows an embodiment of a viewfinder mark. [Figure 4B] 1 shows an embodiment of a viewfinder mark.

[0009] [Diagram 5] 1 illustrates one embodiment of a print verification system.

[0010] [Figure 6] 1 illustrates one embodiment of scaling correction logic.

[0011] [Figure 7A] 1 illustrates an embodiment of a graphical user interface. [Figure 7B] 1 illustrates an embodiment of a graphical user interface.

[0012] [Figure 8] FIG. 1 is a flow diagram illustrating one embodiment of a process for scaling correction.

[0013] [Figure 9] FIG. 11 is a flow diagram illustrating another embodiment of a scaling correction process.

[0014] [Figure 10] 1 illustrates an embodiment of a computer system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The implementation of multiple print engines in a high speed production printer can often lead to issues with paper shrinkage. For example, paper (or other print media) starts at room temperature with some moisture. However, after the first side of the paper is printed and dried in the first print engine, the paper may experience a significant amount of shrinkage. Furthermore, the paper is cooled and dried in the second print engine before the second side is printed, where it experiences a different amount of shrinkage. Due to the different amounts of shrinkage for each side, the image sizes printed on the front and back of the paper are often different, even when using the same print instructions for both sides of the paper.

[0016] Traditional methods for compensating for such shrinkage involve manually inspecting the printed page to estimate how the front and back sides line up to determine how to scale the two sides. The appropriate scaling is then performed to compensate for the amount of shrinkage (e.g., by scaling two sides down or scaling one side up until they match). Other parameters within the printing system, such as ink coverage (e.g., the amount of ink applied to the page), the operating point of the dryer (e.g., temperature or air flow), and the moisture content of the paper, affect the amount of shrinkage. Furthermore, this scaling correction process must be performed for each paper type implemented in the printer due to different physical properties of paper types that affect paper shrinkage.

[0017] According to one embodiment, a mechanism for automatically performing a scaling correction to compensate for paper shrinkage is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the underlying principles of the present invention.

[0018] In the specification, a reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification do not necessarily all refer to the same embodiment.

[0019] Throughout this document, terms such as "logic," "component," "module," "engine," "model," "computer," etc. may be referred to interchangeably and may include, by way of example, any combination of software and hardware, such as software, hardware, and / or firmware. Additionally, any use of a particular brand, word, term, phrase, name, and / or acronym should not be read as limiting embodiments to a product or software or device that carries that label in literature outside of this document.

[0020] FIG. 1 is a block diagram illustrating one embodiment of a printing system 100. As shown in FIG. 1, the printing system 100 includes a tandem duplex continuous form printer 100 including a first print engine 110, a second print engine 120, and a print controller 200. The first print engine 110 and the second print engine 120 each have an inlet 114, an outlet 116, one or more print heads 112, etc. A paper feed unit 160 feeds paper 140 (e.g., continuous form print media, also known as a web) to the printing system, typically a paper roll unwinder that unwinds paper from a large roll. The paper 140 exits the paper feed unit 160 and is fed to the inlet of a splicing unit 190. When the paper roll in the paper feed unit 160 is near the end, the splicing unit 190 responds by applying a splice between a section of paper from the first roll, which is nearly empty, and a section of paper from the second roll, which is full. The second roll of paper may be part of the paper feeding unit 160 or the splicing unit 190.

[0021] Additionally, the feeding unit 160 and / or the splicing unit 190 may include a web buffer (e.g., a web festoon) that stores a length of the paper 140 (e.g., a web) having sides 140A and 140B. One use of the web buffer is to increase the time from detection of the splice 144 to when the splice 144 reaches the inlet 114 of the first print engine 110 by storing a known amount of web length and positioning the sensor 102 to detect the splice upstream of the web buffer. The amount of web length stored may be constant and fixed or may be otherwise identified upon detection of the splice 144 by the sensor 102.

[0022] In other embodiments, the functions of the paper feed unit 160 and the splicing unit 190 may be combined into one device. The paper 140 exits the splicing unit 190 and is fed into the print engine inlet 114, travels along the paper path 128 through the print engine 110, passes the print head 112 and exits through the outlet 116. Other components of the print engines 110 and 120, such as paper rollers, paper guides, paper drive mechanisms, paper tensioners and dryers, are not shown for the sake of simplicity. Besides the continuous paper roll format, the paper 140 may be a folded type of continuous paper that may alternatively be fed into the first print engine 110.

[0023] The paper 140 may include one or more splices 144 secured to one or more sections of the paper 140. The paper 140 advances generally in a paper process direction 142 (e.g., x-direction) during printing. The paper path 128 is the physical path that the paper 140 follows as it begins at the paper feed unit 160 and ends at the post-processing device 170, including the path through all devices in between. The print head 112 includes one or more pixel forming elements that use the marking material applied to the paper 140 to directly or indirectly (e.g., by movement of the marking material through an intermediary) form a representation of a picture element (pixel) on the paper 140 (e.g., print medium).

[0024] In an inkjet printer, the pixel forming elements are tangible devices (e.g., inkjet nozzles) that eject ink onto the paper, and in an electrophotographic (EP) printer, the pixel forming elements may be tangible devices (e.g., EP exposure LEDs or EP exposure lasers) that determine the location of the toner particles printed on the print medium. Additionally, pixel forming elements may be assigned to one of one or more color planes that correspond to the type of marking material (e.g., cyan, magenta, yellow, and black (CMYK)). The space between the nozzle surface of the printhead 112 and the surface of the paper 140 (or the surface of the splice 144) that faces away from the nozzle surface of the printhead 112 is the printhead gap 126.

[0025] The paper 140 is conveyed through a paper inversion unit 150 at the output of the first printer, so that the second printer prints on the reverse side of the output of the first printer, thereby realizing tandem double-sided printing. The functions of each unit in the second print engine 120, such as the inlet 114, the outlet 116, and one or more print heads 112, are the same as those of the first print engine 110. The print controller 200 receives print job data from the upper computers 130, 132, etc., performs a drawing process, and then outputs image data to the first print engine 110 and the second print engine 120.

[0026] The host computer 130 is connected to the print controller 200 via a network 135. The network 135 may be a LAN, a WAN, or a cloud. The host computer 132 is connected to the print controller 200 via a local interface. Physically, the local interface is realized as a printer local I / F cable. In the tandem double-sided printing mode, the paper inverting unit 150 inverts the printed side of the paper 140 for the first side printed by the first print engine 110, and outputs the paper 140 from the exit 116 toward the second print engine 120. In the tandem single-sided printing mode, the paper 140 passes through the paper inverting unit 150 without being inverted. The second print engine 120 receives the paper 140 transported through the paper inverting unit 150 at the entrance 114 of the second print engine 120. A paper path mechanism (not shown) advances the paper 140 along the paper path 128 toward a printing process, such as the printhead 112 of the second print engine 120 .

[0027] In this manner, by using the paper inverting unit 150, tandem duplex printing is achieved by first printing with the first printer engine 110 and then printing with the second print engine 120. The paper 140 printed by the second print engine 120 is output through the outlet 116 to a print verification system (PVS) 180 or a post-processing device 170 according to the paper loading by the operator.

[0028] In one embodiment, the PVS 180 is implemented to capture a print image of a surface of a print substrate (e.g., paper) and determine print quality defects on the substrate. The print quality defects may be defects from defective print markings on the substrate and / or physical defects in the substrate (e.g., impurities, specks, smudges, flutter, temporary wrinkles, wrinkles, and / or z-direction defects). In one embodiment, the PVS 180 may transmit the captured print image and report the results of any detected defects to the print controller 200 for further processing.

[0029] The post-processing device 170 may be a paper roll unwinder or a sheet cutter with a sheet stacker. Output to the paper roll unwinding type post-processing device 170 is particularly effective when the paper roll unwinding type paper feed unit 160 is used as the paper feed for the first print engine 110.

[0030] In the tandem duplex printing mode, after printing is performed on the front side of the paper 140 by the first print engine 110, the paper 140 is inverted by the paper inverting unit 150 and then fed to the second print engine 120. The second print engine 120 prints on the back side of the inverted paper 140. That is, the second print engine 120 prints on the opposite side of the paper 140 printed by the first print engine 110. In the tandem simplex printing mode, after printing is performed on the front side of the paper 140 by the first print engine 110, the paper inverting unit 150 feeds the paper 140 to the second print engine 120 without inverting it. In the printing system 100, the paper 140 may be allowed to remain uninverted by bypassing the paper inverting unit 150 or removing the paper inverting unit 150 from the printing system 100. When such a configuration is adopted, the second print engine 120 also prints on the front side of the paper 140, just like the first print engine 110.

[0031] 2A and 2B are block diagrams illustrating an embodiment of a print controller 200. As shown in FIG. 2A, print controller 200 (e.g., DFE or digital front end) in its generalized form includes an interpreter module 212, a halftone processing module 214, and a scaling module 220. FIG. 2B illustrates an alternative embodiment having print controllers 200A and 200B. In this embodiment, print controller 200A includes interpreter module 212 and halftone processing module 214, and print controller 200B includes scaling module 220. Print controllers 200A and 200B may be implemented within the same printing system 100 (as shown) or may be implemented separately.

[0032] The interpreter module 212 is operable to interpret, render, rasterize, or otherwise convert an image of a print job (e.g., a raw sheetside image such as sheet image 120) into a sheetside bitmap. The sheetside bitmaps generated by the interpreter module 212 are each a two-dimensional array of pixels (i.e., a Continuous Tone Image (CTI)) that represents an image of the print job, also referred to as a full sheetside bitmap. The two-dimensional pixel array is considered a "full" sheetside bitmap because the bitmap contains a set of pixels of the image. In one embodiment, the interpreter module 212 is operable to interpret or render multiple raw sheetsides simultaneously such that the rendering speed substantially matches the speed of the image processing of the production print engine.

[0033] The halftone processing module 214 is operable to represent the sheetside bitmap as a halftone pattern of inks. For example, the halftone processing module 214 may convert pixels to a halftone pattern of CMYK inks for application to paper. The halftone design may include a predefined mapping of input pixel gray levels to output drop sizes based on pixel location.

[0034] As discussed above, the problem of differing amounts of shrinkage between the front and back sides of paper 140 while operating in a duplex mode can lead to undesirable printed image size differences between the two sides of paper 140. According to one embodiment, scaling module 220 is implemented to facilitate automatic scaling to compensate for such shrinkage.

[0035] 3 illustrates one embodiment of the scaling module 220, including a test page generator 310, an interface 320, and scaling application logic 330. The test page generator 310 generates a quality test page having a pattern that facilitates scaling measurements in the PVS 180. In one embodiment, the quality test page includes finder marks (or test marks) that extend across the paper 140 at known locations. FIG. 4A illustrates one embodiment of a test page with test marks 410, and FIG. 4B illustrates one embodiment of a close-up view test mark 410.

[0036] In a further embodiment, the test marks are printed on each printable side of the paper 140 by the print engines 110 and 120 according to the test mark printing instructions. In this embodiment, the test marks on the two sides are not instructed to be placed on top of each other, which provides the technical advantage of reducing ink bleeding through other paper sides that may interfere with the scaling measurements. In yet another embodiment, the quality test page may include a separate test page used during offline printer calibration. In another embodiment, the test marks are printed without applying a scaling factor correction, which has the advantage that other processes that rely on the same text marks are not affected by the scaling of the test marks. However, in an alternative embodiment, the test pages may be incorporated into the production print pages during the processing of an online print job, with the technical advantage of not using separate test pages that are discarded after printing. In this embodiment, each test page printing instruction is included in the print instructions associated with the print job.

[0037] 3, interface 320 includes an application programming interface (API) that facilitates communication with the scaling correction logic in PVS 180. According to one embodiment, interface 320 is configured to receive an update message from PVS 180. In such an embodiment, the update message includes a scaling factor correction (or an updated scaling factor correction) generated in PVS 180. In other embodiments, the update message may include a scaling factor error message, as discussed in more detail below. Scaling application logic 330 applies the scaling factor correction to print instructions associated with the print job being printed. In one embodiment, the scaling factor correction is applied to the processing of the print instructions in interpreter module 212.

[0038] Once printed on paper 140, the test pages are then received by PVS 180 for quality inspection. Figure 5 illustrates one embodiment of PVS 180, which includes an image capture device 510, a registration engine 520, and a controller interface 540. In one embodiment, image capture device 510 includes one or more cameras. However, in other embodiments, image capture device 510 may include different types of image capture devices.

[0039] The image capture device 510 may provide image measurements (e.g., pixel reflectance, intensity, location, etc.) for each of one or more color bands. In such an embodiment, the one or more image capture devices 510 capture (or scan) an image of the print media after the bitmap print image data (or bitmap data) is applied onto the print media using the marking material. The image capture device 510 may transmit the resulting print image data corresponding to one or more color bands (e.g., red, green, blue, etc.) and / or grayscale bands. In one embodiment, the image capture device 510 captures an image of the test marks printed on the test page and generates evaluation print image data (or evaluation reference image data) for each side of the test page. In a further embodiment, the evaluation print image data includes pixel locations of the test marks.

[0040] The registration engine 520 receives the obtained evaluation print image data (e.g., print image) and registers the evaluation print image data with the expected print image data (e.g., bitmap print image data, bitmap image, or other test mark source printing instructions identifying the indicated positions and / or dimensions of the test marks on the test page). The registration engine 520 may receive the expected print image data or access the expected print image data by retrieving it from a stored memory. According to one embodiment, the registration process may be implemented by performing color transformation, rotation, skew transformation, translation, and / or scaling operations on the print media image and / or the bitmap image to obtain a consistent registration between the test marks in the evaluation print image data and the test marks in the expected print image data. Thus, the registration engine may include a scaling correction logic 530 for performing a scaling correction based on the test marks included in the various test pages. The controller interface 540 includes an API configured to interface with the interface 320 of the print controller 200. In one embodiment, the controller interface 540 sends an update message to the interface 320 including the scaling factor correction.

[0041] FIG. 6 illustrates one embodiment of the scaling correction logic 530. According to one embodiment, the scaling correction logic 530 receives first evaluated print image data associated with printed test marks on the paper 140 from a first side of a print image of a print job and second evaluated print image data associated with printed test marks from a second side of the print image, generates a first surface scaling factor based on the first evaluated print image data and the expected print image data, generates a second surface scaling factor based on the second evaluated print image data and the expected print image data, generates a first page scaling factor including a first surface scaling factor and a second surface scaling factor, and generates a scaling factor correction based on the page scaling factor. As used herein, a surface scaling factor represents an amount of scaling for one or more dimensions of a single print media surface, a page scaling factor represents a surface scaling factor for each surface of the print media, and a scaling factor correction represents an adjustment to match a format of a print instruction. For example, if the print instruction has a command for scaling, the page scaling factor is adjusted to be compatible with the print instruction command. This may include expressions such as percentages, relative amounts, absolute amounts and converted units of measurement.

[0042] As shown in FIG. 6, the scaling correction logic 530 includes a scaling logic 610, a correction factor generation module 620, a correction factor database 630, and a scaling factor monitor 640. The area scaling logic 610 generates an area scaling factor by comparing dimensions. The scaling factor may be determined for one or more test mark dimensions. For example, the test mark dimensions may include first and second dimensional components (e.g., process direction x and cross-process direction y dimensions that are Cartesian coordinate dimensions on the printable surface of the printed page) from the evaluated printed image data and from the expected printed image data (e.g., data including expected test mark dimensions and / or locations). In one embodiment, a comparison is made for each side of the print media (e.g., a dimension from the evaluated printed image of the first side is compared to a corresponding dimension from the expected printed image of the first side, etc.). The expected printed image data may be included in printing instructions (e.g., received or retrieved from a stored memory) associated with the print job. The scaling logic 610 may determine the measured dimensions from the evaluated printed image data (e.g., by counting pixels that include the identified test marks).

[0043] According to one embodiment, generating a surface scaling factor for each surface includes averaging measured dimensions of two or more test marks. A technical advantage gained from this averaging is that the effects of spurious measurement data are minimized. In a further embodiment, an affine matrix (e.g., a two-dimensional affine transformation) is used to determine the scaling factor for each surface (e.g., by determining the coefficients of the affine matrix). As used herein, affine is a mathematical method of transforming measured test mark positions to expected test mark positions. By using the parameters of the affine matrix, the scaling factor, rotation, translation may be determined. However, in this case, the function uses the scaling factor result. A technical advantage gained by applying the affine matrix is ​​that the scaling factor is determined with less computational load than other methods.

[0044] According to one embodiment, the scaling logic 610 generates page scaling factors, including an area scaling factor generated for each page area. The correction factor generation module 620 is implemented to generate scaling factor corrections that are sent to the scaling application logic 330 of the print controller 200 (e.g., via interfaces 540 and 320) for application to pages of a subsequent print job or the current print job. The scaling factor corrections may include corrections for one or more dimensions.

[0045] In one embodiment, the scaling factor correction is stored in the correction factor storage 630. In such an embodiment, the scaling factor correction is stored according to a media identifier associated with the print medium (e.g., media metadata such as media type or media name). In further embodiments, the scaling factor correction may be stored along with other print processing parameters specific to the print medium identifier. Thus, multiple print medium print processing parameter sets may be stored along with other print processing parameters specific to the print medium identifier. The stored data is then retrieved (e.g., using the media identifier) ​​and applied during printing of a subsequent print job using the same print medium, thus providing the technical advantage of avoiding another cycle of test page measurements. For example, the scaling correction logic 530 may receive notification of a second print job to be printed on a second print medium, retrieve a second scaling factor correction based on the second print medium identifier (e.g., a second print medium identifier included in the second print job), and apply the second scaling factor correction to the print instructions associated with the second print job.

[0046] According to one embodiment, the updated scaling factor correction may be generated based on an average of multiple previous scaling factor correction amounts. For example, the scaling factor correction generated based on the scaling process of the first test page and the scaling factor correction generated based on the scaling process of the second test page are averaged to generate the updated scaling factor correction. A technical advantage gained from the averaging is that the updated scaling factor correction does not change abruptly from the previous scaling factor correction amount, and differences in the print output generated with the updated scaling factor are less noticeable to a human observer.

[0047] According to another embodiment, the scaling correction logic 530 may receive third evaluated printed image data associated with printed test marks on the print medium from a first side of a second page image of the print job and fourth evaluated printed image data associated with printed test marks on the print medium from a second side of the second page image, generate a third side scaling factor based on the third evaluated printed image data, generate a fourth side scaling factor based on the fourth evaluated printed image data, generate a second page scaling factor based on the third side scaling factor and the fourth side scaling factor, and update the scaling factor correction based on the second page scaling factor.

[0048] The scaling factor monitor 650 monitors the scaling factors during production printing to determine whether the difference between two corresponding generated scaling factors (e.g., facet scaling factor, page scaling factor, and / or scaling factor correction) generated at different times exceeds a predetermined threshold. In one embodiment, a scaling factor error message is generated when it is determined that the difference between the different scaling factors exceeds a threshold. In a further embodiment, the scaling factor error message is included in an update message sent to the scaling module 220 and displayed in the graphical user interface (GUI) 350 (FIG. 3) as an operator alert. In yet another embodiment, the scaling application logic 330 may generate a trigger to stop the printer 100 and / or to start the calculation of new scaling values ​​upon receiving a scaling factor error message. A technical advantage gained by determining a scaling factor error is that the scaling correction logic 530 may initiate an alert message to an operator to take recovery action and / or initiate recovery action in response to the scaling factor error, thus minimizing the amount of printed output with scaling issues.

[0049] The GUI 350 may also be implemented to allow operator selection to provide real-time correction options, including front-to-back registration options. For example, a user may select to compensate for front-to-back registration where test marks (e.g., scaling test marks) are used in conjunction with other quality test marks (e.g., uniformity marks, density marks, and / or registration marks) included on a printed "quality check" page, with a "quality check" page inserted at a specified interval, with the technical advantage of reducing the number of separate test pages required when the scaling marks are not located on the same page as other quality marks. Figures 7A and 7B show an embodiment of the GUI 350 including various front-to-back registration options, including a scaling operation.

[0050] Although described as being included within PVS 180, the scaling correction logic 530, or one or more of its components, may be implemented in print controller 200. Figure 2C illustrates an embodiment in which the scaling correction logic 530 is included in print controller 200B, which has scaling module 220. In this embodiment, measurements generated by image capture device 510 are sent via interfaces 540 and 320 to print controller 200A, where the scaling correction is performed.

[0051] FIG. 8 is a flow diagram illustrating one embodiment of a scaling correction process 800 (e.g., executed in the print controller 200). The process 800 may be performed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, etc.), software (e.g., instructions running on a processing device), or a combination thereof. Although the process 800 is shown in a linear sequence for simplicity and clarity of presentation, it is contemplated that any number of them may be performed in parallel, asynchronously, or in a different order. For the sake of brevity, clarity, and ease of understanding, many of the details discussed with reference to FIGS. 1-7 will not be discussed or repeated here.

[0052] At process block 810, a test page is generated that includes test marks that are printed on each printable side of the test page. The test page is then inserted into the print instructions. At process block 820, the page image is printed. In the meantime, an update message is received (block 830) after the scaling correction has been performed. At decision block 840, a determination is made as to whether the update message includes a scaling factor error message. If not, the update message includes a scaling factor correction (or an updated scaling factor correction) that is applied to subsequent pages to be printed (e.g., by inserting the scaling factor correction into the print instructions for the corresponding side processed by print controller 200) (processing block 850). The scaling factor correction is applied to one or more dimensions of the corresponding side of the subsequent pages to be printed. However, if at decision block 840, it is determined that a scaling factor error message has been received, an error message is displayed in GUI 350 (processing block 860). At process block 870, if applicable, a corrective action (e.g., stop printing) is performed.

[0053] 9 is a flow diagram illustrating one embodiment of a scaling correction process 900 (e.g., performed in PVS 180). Process 900 may be performed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, etc.), software (e.g., instructions running on a processing device), or a combination thereof. Process 900 is shown in a linear sequence for brevity and clarity of presentation, but it is contemplated that any number of them may be performed in parallel, asynchronously, or in a different order. For brevity, clarity, and ease of understanding, many of the details discussed with reference to FIGS. 1-8 will not be discussed or repeated here.

[0054] At process block 910, test marks on both sides of a test page are captured. At process block 920, measurement data including test mark dimensions is generated for the captured test marks. At process block 930, area scaling factors are generated by comparing dimensions based on the evaluated printed image data and dimensions based on the expected printed image data. As discussed above, the area scaling factors may be generated by averaging two or more test marks (e.g., by an affine transformation performed on the averaged measured dimensions).

[0055] At process block 940, a page scaling factor is generated (e.g., GENERATED PAGE SCALING FACTOR). At decision block 950, a determination is made as to whether a difference between the generated page scaling factor and the previous page scaling factor is greater than a predetermined threshold. If so, a scaling factor error message is generated (processing block 960). At process block 970, the scaling factor error message is sent (e.g., to print controller 200).

[0056] If at decision block 950 it is determined that the difference between the page scaling factor and the previous page scaling factor is not greater than a predetermined threshold, then a scaling factor correction (or an updated scaling factor correction) is generated (processing block 980). As discussed above, the updated scaling factor correction may include an averaging of two or more previously generated scaling factor corrections. At processing block 990, the scaling factor correction is stored (e.g., along with an associated print medium identifier) ​​prior to being transmitted at processing block 970 (processing block 990).

[0057] 10 illustrates a computer system 1300 upon which printers 110 and 120, printing system 100, print controller 200, and / or PVS 190 may be implemented. Computer system 1300 includes a system bus 1320 for communicating information and a processor 1310 coupled to bus 1320 for processing information.

[0058] Computer system 1300 further includes a random access memory (RAM) or other dynamic storage device 1327 (herein referred to as main memory), coupled to bus 1320 for storing information and instructions executed by processor 1310. Main memory 1325 may also be used for storing temporary variables or other intermediate information during execution of instructions by processor 1310. Computer system 1300 may also include a read only memory (ROM) and / or other static storage device 1326, coupled to bus 1320, for storing static information and instructions used by processor 1310.

[0059] A data storage device 1327, such as a magnetic or optical disk and its corresponding drive, may also be connected to the computer system 1300 for storing information and instructions. The computer system 1300 may also be connected to a second I / O bus 1350 via an I / O interface 1330. A number of I / O devices, including a display device 1324, input devices (e.g., a keyboard 1323 (e.g., an alphanumeric input device) and / or a cursor control device 1322) may also be connected to the I / O bus 1350. The communication device 1321 is for accessing other computers (servers or clients). The communication device 1321 may include a modem, a network interface card, or other well-known interface devices such as those used to connect to an Ethernet, Token Ring, or other type of network.

[0060] An embodiment of the present invention may include various steps as described above. The steps may be embodied in machine-executable instructions. The instructions may be used to cause a general-purpose or special-purpose processor to perform certain steps. Alternatively, the steps may be performed by specific hardware components that contain hardwired logic for performing the steps, or by any combination of programmed computer components and custom hardware components.

[0061] The elements of the present invention may also be provided as a machine-readable medium for storing machine-executable instructions. Machine-readable media include, but are not limited to, floppy disks, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards, propagation media, or other types of media / machine-readable media suitable for storing electronic instructions. For example, the present invention may be downloaded from a remote computer (e.g., a server) to a requesting computer (e.g., a client) as a computer program that may be transferred by a data signal embodied in a carrier wave or other propagation medium via a communications link (e.g., a modem or network connection).

[0062] The following sections and / or examples relate to further embodiments or examples. Details in the examples may be used anywhere in one or more embodiments. Various features of the various embodiments or examples may be combined in various ways with some features included and other features excluded to suit a variety of different applications. Examples may include subject matter such as a method, a means for performing the actions of the method, at least one machine-readable medium including instructions that, when executed by a machine, cause the machine to perform the actions of the method, a device, or a system, according to the embodiments and examples described herein.

[0063] Some embodiments relate to Example 1, which includes a system including at least one physical memory device storing scaling correction logic and one or more processors coupled to the at least one physical memory device, the one or more processors executing the scaling correction logic to receive first evaluated printed image data associated with test marks printed on a first side of a print medium based on a print job and second evaluated printed image data associated with test marks printed on a second side of the print medium, generate a first surface scaling factor based on the first evaluated printed image data, generate a second surface scaling factor based on the second evaluated printed image data, and generate a scaling factor correction based on the generated first surface scaling factor and second surface scaling factor.

[0064] Example 2 includes the subject matter of Example 1, generating an area scaling factor by comparing dimensions based on the evaluated printed image data to dimensions based on expected printed image data expected from the print job.

[0065] Example 3 includes the subject matter of Examples 1 and 2, generating area scaling factors based on expected print image data expected from a print job contained in print instructions associated with the print job.

[0066] Example 4 includes the subject matter of Examples 1-3, generating an area scaling factor by averaging measured dimensions of two or more of the test marks.

[0067] Example 5 includes the subject matter of examples 1-4, where the areal scaling coefficients include a first dimensional scaling component and a second dimensional scaling component.

[0068] Example 6 includes the subject matter of examples 1-5, wherein generating the surface scaling factor further includes performing an affine transformation on the averaged measured dimensions.

[0069] Example 7 includes the subject matter of Examples 1-6, where the test marks are printed without applying scaling factor correction.

[0070] Example 8 includes the subject matter of Examples 1-7, where the scaling correction logic further stores the scaling factor correction.

[0071] Example 9 includes the subject matter of examples 1-8, wherein the scaling correction logic further comprises: associating the scaling factor correction with a print medium identifier associated with the print medium; and storing the scaling factor correction.

[0072] Example 10 includes the subject matter of Examples 1-9, wherein the scaling correction logic further receives notification of a second print job to be printed on a second print medium, retrieves a second scaling factor correction based on a print medium identifier of the second print medium, and applies the second scaling factor correction to print instructions associated with the second print job.

[0073] Example 11 includes the subject matter of Examples 1-10, where the scaling correction logic further receives third evaluation print image data associated with test marks printed on the print medium from a first side of a second page image of the print job and fourth evaluation print image data associated with test marks printed on the print medium from a second side of the second page image, generates a third surface scaling factor based on the third evaluation print image data, generates a fourth surface scaling factor based on the fourth evaluation print image data, and updates the scaling factor correction based on the generated third surface scaling factor and fourth surface scaling factor.

[0074] Example 12 includes the subject matter of Examples 1-11, where the scaling correction logic is further configured to generate an updated scaling factor correction based on an average of a first page scaling factor based on the generated first and second surface scaling factors and a second page scaling factor based on the generated third and fourth surface scaling factors.

[0075] Example 13 includes the subject matter of Examples 1-12, where the scaling correction logic further determines whether a difference between the scaling factor correction before the update and the scaling factor correction after the update exceeds a predetermined threshold, and generates an alert if it is determined that the difference exceeds the predetermined threshold.

[0076] Example 14 includes the subject matter of Examples 1-13, further including one or more image capture devices that capture images of the print job.

[0077] Example 15 includes the subject matter of Examples 1-14, further including one or more printers for printing the print jobs.

[0078] Some embodiments relate to Example 16, which includes a method including receiving first evaluation printed image data associated with test marks printed on a first side of a printing medium based on a print job and second evaluation printed image data associated with test marks printed on a second side of the printing medium, generating a first surface scaling factor based on the first evaluation printed image data, generating a second surface scaling factor based on the second evaluation printed image data, and generating a scaling factor correction based on the generated first surface scaling factor and second surface scaling factor.

[0079] Example 17 includes the subject matter of Example 16, generating an area scaling factor by comparing dimensions based on the evaluated printed image data to dimensions based on expected printed image data expected from the print job.

[0080] Example 18 includes the subject matter of Examples 16 and 17, generating area scaling factors based on expected print image data expected from a print job contained in print instructions associated with the print job.

[0081] Example 19 includes the subject matter of Examples 16-18, generating an area scaling factor by averaging measured dimensions of two or more of the test marks.

[0082] Example 20 includes the subject matter of examples 16-19, further including storing the scaling factor correction.

[0083] Some embodiments are related to Example 21, which includes at least one computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause the processor to receive first evaluated printed image data associated with test marks printed on a first side of a printing medium based on a print job and second evaluated printed image data associated with test marks printed on a second side of the printing medium, generate a first surface scaling factor based on the first evaluated printed image data, generate a second surface scaling factor based on the second evaluated printed image data, and generate a scaling factor correction based on the generated first surface scaling factor and second surface scaling factor.

[0084] Example 22 includes the subject matter of Example 21, generating an area scaling factor by comparing dimensions based on the evaluated printed image data to dimensions based on expected printed image data expected from the print job.

[0085] Example 23 includes the subject matter of Examples 21 and 22, generating area scaling factors based on expected print image data expected from a print job contained in print instructions associated with the print job.

[0086] Example 24 includes the subject matter of Examples 21-23, generating an area scaling factor by averaging measured dimensions of two or more of the test marks.

[0087] Example 25 includes the subject matter of examples 21-24, further including storing the scaling factor correction.

[0088] Although many variations and modifications of the present invention will no doubt become apparent to those skilled in the art after reading the foregoing description, it should be understood that any particular embodiments shown and described by way of illustration are not intended to be regarded as limiting in any way. Accordingly, reference to details of various embodiments is not intended to limit the scope of the claims, which in themselves define only those features regarded as essential.

Claims

1. 1. A system comprising: at least one physical memory device that stores scaling correction logic; and one or more processors coupled to the at least one physical memory device, the one or more processors executing the scaling correction logic to: receiving first evaluation print image data associated with test marks printed on a first side of a print medium based on a print job and second evaluation print image data associated with test marks printed on a second side of the print medium; generating a first surface scaling factor based on the first evaluation print image data and generating a second surface scaling factor based on the second evaluation print image data; generating a scaling factor correction based on the generated first surface scaling factor and the second surface scaling factor.

2. The system of claim 1 , further comprising: generating an area scaling factor by comparing dimensions based on evaluated printed image data to dimensions based on expected printed image data expected from the print job.

3. The system of claim 2 , further comprising: generating an area scaling factor based on expected print image data expected from the print job contained in a print instruction associated with the print job.

4. The system of claim 2 , further comprising: generating an area scaling factor by averaging measured dimensions of two or more of the test marks.

5. The system of claim 4 , wherein the areal scaling factors include a first dimensional scaling component and a second dimensional scaling component.

6. The system of claim 5 , wherein generating the surface scaling factor further comprises performing an affine transformation on the averaged measured dimensions.

7. The system of claim 1 , wherein the test marks are printed without applying the scaling factor correction.

8. The system of claim 1 , wherein the scaling correction logic is further operable to store the scaling factor correction.

9. The scaling correction logic further comprises: Associating the scaling factor correction with a print medium identifier associated with the print medium; The system of claim 8 , further comprising storing and performing the scaling factor correction.

10. The scaling correction logic further comprises: receiving notification of a second print job to be printed on a second print medium; deriving a second scaling factor correction based on a print medium identifier of the second print medium; and applying the second scaling factor correction to print instructions associated with the second print job.

11. The scaling correction logic further comprises: receiving third evaluation print image data associated with test marks printed on the print medium from a first side of a second page image of the print job, and fourth evaluation print image data associated with test marks printed on the print medium from a second side of the second page image; generating a third surface scaling factor based on the third evaluation print image data, and generating a fourth surface scaling factor based on the fourth evaluation print image data; and updating the scaling factor correction based on the generated third surface scaling factor and the generated fourth surface scaling factor.

12. 12. The system of claim 11, wherein the scaling correction logic further generates an updated scaling factor correction based on an average of a first page scaling factor based on the generated first and second surface scaling factors and a second page scaling factor based on the generated third and fourth surface scaling factors.

13. The scaling correction logic further comprises: determining whether a difference between the scaling factor correction before updating and the scaling factor correction after updating exceeds a predetermined threshold; and generating an alert upon determining that the difference exceeds the predetermined threshold.

14. The system of claim 1 , further comprising one or more image capture devices for capturing images of the print job.

15. The system of claim 1 , further comprising one or more printers for printing the print jobs.

16. 1. A method comprising: receiving first evaluation print image data associated with test marks printed on a first side of a print medium based on a print job and second evaluation print image data associated with test marks printed on a second side of the print medium; generating a first surface scaling factor based on the first evaluation print image data and generating a second surface scaling factor based on the second evaluation print image data; generating a scaling factor correction based on the generated first surface scaling factor and the second surface scaling factor.

17. The method of claim 16 , further comprising generating an area scaling factor by comparing dimensions based on evaluated printed image data to dimensions based on expected printed image data expected from the print job.

18. The method of claim 17 , further comprising generating an area scaling factor based on expected print image data expected from the print job contained in print instructions associated with the print job.

19. The method of claim 17 , further comprising generating an area scaling factor by averaging measured dimensions of two or more of the test marks.

20. The method of claim 16 , further comprising storing the scaling factor correction.

21. At least one computer-readable medium having instructions stored thereon, the instructions, when executed by one or more processors, causing the processors to: receiving first evaluation print image data associated with test marks printed on a first side of a print medium based on a print job and second evaluation print image data associated with test marks printed on a second side of the print medium; generating a first surface scaling factor based on the first evaluation print image data and generating a second surface scaling factor based on the second evaluation print image data; generating a scaling factor correction based on the generated first surface scaling factor and the second surface scaling factor.

22. 22. The computer readable medium of claim 21, generating an area scaling factor by comparing dimensions based on evaluated printed image data to dimensions based on expected printed image data expected from the print job.

23. 23. The computer readable medium of claim 22, further comprising generating an area scaling factor based on expected print image data expected from the print job contained in print instructions associated with the print job.

24. 23. The computer-readable medium of claim 22, further comprising generating an area scaling factor by averaging measured dimensions of two or more of the test marks.

25. 22. The computer readable medium of claim 21 having stored thereon instructions that, when executed by one or more processors, further cause the processors to store the scaling factor correction.

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