Defective nozzle compensation mechanism

Abstract

A printing system is disclosed. The printing system includes at least one physical memory device for storing calibration logic and one or more processors coupled to the at least one physical memory device to execute the calibration logic, thereby generating a uniformly compensated halftone design for each of a plurality of primitive forming elements, generating a missing neighbor corrected halftone design for each of the plurality of primitive forming elements, generating a missing neighbor threshold reduction function for each of the plurality of primitive forming elements based on the uniformly compensated halftone design and the missing neighbor corrected halftone design, and calculating the average of the missing neighbor threshold reduction functions to generate an average missing neighbor threshold reduction function.

Description

Technical Field

[0001] This invention relates to the field of image reproduction, and particularly to ejection correction. Background Technology

[0002] Entities with high-volume printing needs typically implement high-speed production printers for batch printing (e.g., one hundred pages per minute or more). Production printers can include continuous-form printers that print on rolls of printing media (or paper) stored in large rolls. Production printers typically include a local print controller that controls the overall operation of the printing system, and a print engine that includes one or more printhead assemblies, each of which includes a printhead controller and printheads (or an array of printheads). Each printhead contains a number of nozzles for ejecting ink or any colorant suitable for printing on the media.

[0003] Before starting a printing operation, uniformity compensation can be performed to compensate for differences in the measured response of un-sprayed printhead nozzles. However, various nozzles may become defective during printer operation, which can lead to variations in ejection output (ejection conditions) caused by defective nozzles. Summary of the Invention

[0004] Technical issues

[0005] Currently, printers must be taken offline to perform subsequent uniformity compensation to correct defective nozzles. Taking the printer offline is undesirable because stopping printing production results in lost revenue. Therefore, a mechanism for real-time correction of ejection conditions is needed.

[0006] Solution to the problem

[0007] In one embodiment, a printing system is disclosed. The printing system includes at least one physical memory device and one or more processors, the at least one physical memory device storing calibration logic, the one or more processors coupled to the at least one physical memory device to execute the calibration logic to generate a uniformly compensated halftone design for each of a plurality of primitive forming elements, generate a missing neighbor corrected halftone design for each of the plurality of primitive forming elements, generate a missing neighbor threshold reduction function for each of the plurality of primitive forming elements based on the uniformly compensated halftone design and the missing neighbor corrected halftone design, and calculate the average of the missing neighbor threshold reduction functions to generate an average missing neighbor threshold reduction function. Attached Figure Description

[0008] A better understanding of the invention can be obtained from the following detailed description in conjunction with the accompanying drawings, wherein:

[0009] Figure 1This is a block diagram of one embodiment of a printing system;

[0010] Figure 2 This is a block diagram of one embodiment of the print controller;

[0011] Figure 3 An embodiment of the calibration module is illustrated;

[0012] Figure 4 The illustration shows an example of the inverse transfer function of a nozzle;

[0013] Figure 5 This is a flowchart illustrating one embodiment of the uniformity compensation process performed by a printing system;

[0014] Figure 6 This is a flowchart illustrating another embodiment of the uniformity compensation process performed by the printing system;

[0015] Figure 7 This is a flowchart illustrating an embodiment of the process for generating a missing neighbor transfer function;

[0016] Figure 8 This is a flowchart illustrating an embodiment of the process for generating a missing neighbor threshold reduction function;

[0017] Figure 9 An example of a threshold is illustrated;

[0018] Figure 10 This is a flowchart illustrating one embodiment of the missing neighbor process;

[0019] Figure 11 An embodiment of nozzle calibration logic is illustrated;

[0020] Figure 12 This is a flowchart illustrating one embodiment of the nozzle calibration process;

[0021] Figure 13 This is a flowchart illustrating another embodiment of the nozzle calibration process;

[0022] Figure 14 The illustration shows an embodiment of a calibration module implemented in a network; and

[0023] Figure 15 An embodiment of a computer system is illustrated. Detailed Implementation

[0024] A mechanism for real-time correction of ejection conditions is described. In the following description, numerous specific details are set forth for purposes of explanation to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form to avoid obscuring the essential principles of the invention.

[0025] The reference to "one embodiment" or "embodiment" in the specification means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0026] Figure 1 This is a block diagram illustrating one embodiment of the printing system 130. A host system 110 communicates with the printing system 130 to print a sheet image 120 onto a printing medium 180 via a printer 160 (e.g., a print engine). The printing medium 180 may include paper, cardstock, cardboard, corrugated cardboard, film, plastic, synthetic material, fabric, glass, composite material, or any other tangible medium suitable for printing. The format of the printing medium 180 may be continuous, cut sheet, or any other format suitable for printing. The printer 160 may be an inkjet, electrophotographic, or other suitable printer type.

[0027] In one embodiment, printer 160 includes one or more printheads 162, each printhead 162 including one or more primitive forming elements 165 that form a representation of photographic elements (primitives) on print media 180 directly or indirectly (e.g., by transferring marker material through an intermediate), wherein marker material is applied to the print media. In inkjet printers, primitive forming elements 165 are tangible means (e.g., inkjet nozzles) that jet ink onto print media 180, and in electrophotographic (EP) printers, primitive forming elements can be tangible means (e.g., EP exposure LEDs or EP exposure lasers) that determine the position of toner particles printed on the print media.

[0028] In the case of a laser electrophotographic printer, the described method can be used to compensate for a non-operating laser imaging element, wherein multiple beams are used to simultaneously image the photoconductor. In the case of an LED electrophotographic printer, the described method can be used to compensate for a non-operating LED imaging element, wherein an LED array is used to simultaneously image the photoconductor.

[0029] Primitive forming elements can be grouped onto one or more printheads. As a matter of design choice, primitive forming element 165 can be stationary (e.g., as part of a stationary printhead) or moving (e.g., as part of a printhead moving across print media 180). Primitive forming element 165 can be assigned to one or more color planes corresponding to a marking material type (e.g., cyan, magenta, yellow, and black (CMYK)).

[0030] In another embodiment, printer 160 is a multi-pass printer (e.g., two-pass, three-pass, four-pass, etc.) in which multiple sets of primitive forming elements 165 print the same area of ​​the printed image on print medium 180. These sets of primitive forming elements 165 may be located on the same physical structure (e.g., a nozzle array on an inkjet printhead) or on separate physical structures. The resulting print medium 180 may be printed in color and / or in any of a variety of grayscale shades, including black and white (e.g., cyan, magenta, yellow, and black (CMYK)). Host system 110 may include any computing device, such as a personal computer, server, or even a digital imaging device, such as a digital camera or scanner.

[0031] The sheet image 120 can be any file or data describing how an image on a sheet of paper should be printed on the print medium 180. For example, the sheet image 120 may include PostScript data, Printer Command Language (PCL) data, and / or any other printer language data. The print controller 140 processes the sheet image to generate a bitmap 150 for transmission. The bitmap 150 can be a halftone bitmap for printing to the print medium 180 (e.g., a calibrated halftone bitmap generated from calibrated halftones, or an uncalibrated halftone bitmap generated from uncalibrated halftones). The print system 130 can be a high-speed printer operable to print relatively large volumes (e.g., greater than 100 pages per minute).

[0032] The printing medium 180 may be continuous paper, cut sheet paper, and / or any other tangible medium suitable for printing. In a generalized form, the printing system 130 includes a printer 160 that renders a bitmap 150 onto the printing medium 180 based on a sheet image 120 (e.g., via toner, ink, etc.). Although shown as a component of the printing system 130, other embodiments may characterize the printer 160 as a separate device communicatively coupled to a print controller 140.

[0033] The print controller 140 can be any system, apparatus, software, circuitry, and / or other suitable component operable to transform the sheet image 120 to generate a bitmap 150 based on printing onto the print medium 180. In this respect, the print controller 140 may include processing and data storage capabilities. In one embodiment, a measurement module 190 is implemented as part of a calibration system to obtain measurements of the print medium 180. The measurement results are transmitted to the print controller 140 for use during the calibration process. The measurement system may be a standalone process or integrated into the print system 130.

[0034] According to one embodiment, the measurement module 190 may be a sensor that measures a printed image on a printing medium 180. The measurement module 190 may generate and transmit measurement data 222. Measurement data 222 may be OD (e.g., optical density), RGB, or other optical response data corresponding to the printed image. In one embodiment, the measurement module 190 may include one or more sensors, each or all of which perform optical measurements on printed marks generated for some or all primitive forming elements 165. In another embodiment, the measurement module 190 may be a camera system, an inline scanner, a densitometer, or a spectrophotometer. In another embodiment, the measurement data 222 may include mapping information that associates the measurement data 222 (e.g., OD data) with corresponding primitive forming elements 165 that contribute to portions of the measurement data 222. In another embodiment, printing instructions for testing a pattern (e.g., a step chart) provide the correlation between portions of the measurement data 222 and corresponding primitive forming elements 165 that contribute to portions of the measurement data 222.

[0035] Figure 2 This is a block diagram illustrating one embodiment of a print controller 140. The print controller 140, in its generalized form, includes a reader module 212, a halftone module 214, and a calibration module 216. These individual components may represent hardware used to implement the print controller 140. Alternatively or additionally, the individual components may represent logic blocks implemented by executing software instructions in the processor of the print controller 140.

[0036] The interpreter module 212 is operable to interpret, render, rasterize, or otherwise convert images of a print job (e.g., raw sheet face images such as sheet image 120) into sheet face bitmaps. The sheet face bitmaps generated by the interpreter module 212 are all two-dimensional primitive arrays representing images of a print job (i.e., continuous tone images (CTI)), also referred to as complete sheet face bitmaps. A two-dimensional primitive array is considered a “complete” sheet face bitmap because the bitmap includes the entire set of primitives of the image. The interpreter module 212 is operable to interpret or render multiple raw sheet faces simultaneously, such that the rendering rate substantially matches the imaging rate of the production print engine.

[0037] Halftone module 214 is operable to represent a sheet surface bitmap as a halftone pattern of ink. For example, halftone module 214 can convert primitives (also called pixels) into a halftone pattern of CMYK ink for application to paper. Halftone design may include a predefined mapping from input primitive grayscale levels to output droplet sizes based on primitive location.

[0038] In one embodiment, a halftone design may include a finite set of transition thresholds (e.g., a threshold array, such as a unit threshold array or a multi-bit threshold array) between a finite set of successively larger droplet sizes, starting at zero and ending at the largest droplet size. In another embodiment, a halftone design may include a three-dimensional lookup table having all included grayscale level values.

[0039] In another embodiment, halftone module 214 uses a halftone design to perform multi-bit halftoneing, the halftone design consisting of a set of thresholds for each primitive in the sheet surface bitmap, wherein there is a threshold for each non-zero droplet size. The primitive is halftoneted with the droplet size corresponding to the threshold of that primitive. This set of thresholds for the primitive set is called a multi-bit threshold array (MTA).

[0040] Multi-bit halftone is a halftone halftone operation where the final result is the selection of a specific droplet size from the entire set of droplet sizes that the printing engine can use for printing. Droplet size selection based on successive tonal values ​​of individual primitives is called "point operation" halftone. Droplet size selection is based on primitive values ​​in the sheet surface bitmap.

[0041] Calibration module 216 performs a calibration process on the uncalibrated halftone 218 received at print controller 140 or a previously generated uniformity-compensated halftone to generate one or more calibrated halftones 220. The calibrated halftones 220 and a sheet surface bitmap are then received at halftone grading module 214. In one embodiment, the uncalibrated halftone 218 represents a reference halftone design modified to create calibrated halftones. In such an embodiment, measurements (e.g., measurement data 222) of the system response are received via measurement module 190 using the uncalibrated halftone 218 for printing.

[0042] Figure 3 An embodiment of the calibration module 216 is illustrated. Figure 3As shown, calibration module 216 includes uniformity compensation module 310. According to one embodiment, uniformity compensation module 310 performs an iterative process to achieve uniformity compensation for the calibrated halftone. As used herein, uniformity compensation is defined as calibration that compensates for differences in measurement response at individual primitives via primitive forming elements 165 (e.g., printhead nozzles). In some cases, uniformity compensation can be achieved after a single iteration.

[0043] In one embodiment, the uniformity compensation module 310 generates an initial step chart based on the uncalibrated halftone 218. In such an embodiment, the initial step chart uses a threshold array associated with the uncalibrated halftone design to generate a calibrated step chart. However, in subsequent iterations, the step chart is generated based on a threshold array associated with the current uniformity-compensated halftone.

[0044] In another embodiment, the calibration step chart is printed by the primitive forming element 165 of printer 160, and the image of the calibration step chart is measured by measurement module 190 (e.g., via a scanner). In such an embodiment, measurement module 190 generates printed image measurement data that includes OD data for each primitive forming element 165 for a uniform grid across the roll of printing media.

[0045] A calibration step chart typically comprises multiple steps (e.g., strips or bands) of uniform density, where at least one halftone pattern can exist for each color of ink used by the printer. The band density ranges from paper white (no ink) to the maximum density for each ink color. The steps or strips are arranged such that each segment or section of the printhead prints a representative set of shades for each color and each color of ink. Sufficient primitives are included within the height of the strips so that random variations in the halftone design are minimized by density measured averaging along the strip height.

[0046] The uniformity compensation module 310 receives OD data from all nozzles at each color level and determines whether the OD change of the primitive forming element 165 is less than a predetermined threshold associated with a target uniformity compensation specification. OD change is the difference between the average measured OD value (e.g., pixel) of the print produced by one printhead nozzle and the measured OD values ​​from one or more other nozzles in response to the same color value input for printing. In one embodiment, the predetermined threshold is received from the system user at the uniformity compensation module 310 via a graphical user interface (GUI) 340.

[0047] When the change is determined to be less than a predetermined threshold, the uniformity compensation module 310 sends a message indicating that uniformity compensation has been achieved for the halftone (e.g., the OD change is less than the predetermined threshold). However, when the change is determined to be greater than the predetermined threshold, measurement data (e.g., nozzle measurement data) associated with each primitive forming element 165 is generated. In one embodiment, the nozzle measurement data includes interpolation of the measured OD data. Subsequently, the uniformity compensation module 310 can initiate the generation and printing of a modified calibration step chart.

[0048] According to one embodiment, the uniformity compensation module 310 can generate the inverse transfer function (or ITF) of each primitive forming element 165 based on OD data and a received uniformity compensation objective function. According to another embodiment, the uniformity compensation module 310 can generate the transfer function (TF) of each primitive forming element 165 based on OD data and a received uniformity compensation objective function. As defined herein, the transfer function is defined as a mapping from the system's input digital counts to its output digital counts, where the digital counts represent bitmap 150 (…). Figure 1 The grayscale level or color value of primitives in the graph. A transfer function (or inverse transfer function) can be received or generated (e.g., generated based on the target OD with input digit count data and the measured OD with output digit count data).

[0049] An inverse transfer function is the inverse (e.g., reverse) application of digital count data, wherein the output digital count value of the transfer function forms the input digital count value of the inverse transfer function, and the input digital count value of the transfer function forms the output digital count value of the inverse transfer function.

[0050] Figure 4 An example of the inverse transfer function of a nozzle is illustrated. For example... Figure 4 As shown, the inverse transfer function of a primitive forming element (e.g., a nozzle) is expressed as U k (g) = c = TF k -1 (g). Alternatively, T can be used. -1 (M k (g)) Directly calculate the inverse transfer function for all nozzle positions k. The target OD response T(c) is used as the uniformity target for all nozzles in the current halftone, where {h kl} i It is a three-dimensional threshold array of iteration i, column position k, and droplet size level l. The threshold array includes thresholds for all droplet sizes. The threshold of column k is used during halftone printing to print using nozzle k. Therefore, there is a one-to-one correspondence between the nozzles from the inkjet array and the columns of the threshold array.

[0051] For simplicity, rows of the threshold array are not included. Curly braces are used to indicate the set of thresholds. It should be understood that the entire threshold array is three-dimensional, with rows in the roll movement direction, columns corresponding to each nozzle, and planes corresponding to each non-zero droplet size. In one embodiment, the same objective is applied to all nozzles to achieve uniform printing. k Let the inverse transfer function of nozzle k be denoted as , which is in Figure 4 In this context, color value g is mapped to color value c. U k This can be determined by following the dashed path in the opposite direction of the indicated arrow.

[0052] In one embodiment, for a typical 8-bit printing system, color values ​​are digital count (DC) levels ranging from 0 to 255. In such an embodiment, the inverse transfer function of color value g is color value c, and its target value T(c) is the measured value M generated when color value g is printed. k (g). For all nozzles, T(c) can be set to the same value to provide uniformity across all nozzles. Value M k (g) is the OD measured at the cross-printing media (e.g., roll material) position corresponding to nozzle k and the current halftone (e.g., threshold array). k It can be calculated directly, instead of by using M. k (g) Start by inverting TF and then find T. -1 (M k (g) is used to calculate the inverse of the objective function T. -1 The objective function can be found by listing it in two columns with all c and g values ​​and then swapping the columns. The measured response M at nozzle position k. k (g) The entire threshold array used for printing can be used for measurement to include contributions from adjacent compensating nozzles. Scanned image data is used, and the data is interpolated to obtain the measured response of the nozzle at position k. Alternatively, it can be assumed that the measured response and the target response are continuous functions obtained based on regression of the measured data.

[0053] like Figure 4 As shown, the transfer function TF(c) = g. In one embodiment, the transfer function of color value c is color value g. When color value g is printed by the printing system, the target optical density at color value c is obtained as the measurement value for color value g. Figure 4 As shown, TF(c) can be determined by following the dashed path in the direction of the indicated arrow. This is because both c and g have the same optical density OD1 associated with them. Color c appears in the target domain, and color g appears in the measurement domain system. TF(c) can be derived from t(c) and Mk(g) by tabulating the matching color pairs with optical densities as interpreted here for colors c and g. kThen it can be done by TF k The inverse is used to determine this.

[0054] According to one embodiment, the uniformity compensation module 310 generates an updated uniformity-compensated halftone by modifying all thresholds in each column of the threshold array corresponding to the current halftone using an inverse transfer function generated for each corresponding nozzle. In this embodiment, the current threshold {h} of the compensated halftone from the previous iteration is transformed using the inverse transfer function of each column (or nozzle) (k) at each iteration. kl} i-1 This creates a threshold {h} for the compensated halftone. kl} i This process generates thresholds in the compensation threshold array based on the corresponding thresholds from the current threshold array.

[0055] In one embodiment, each threshold of the compensation threshold array is determined by using a transformation defined by the corresponding ITF applied to each threshold for all corresponding primitives and droplet sizes. If it is assumed that the ITF is a continuous function, the transformed threshold is rounded to an integer threshold. The range of thresholds in the created threshold array can match the bit depth of the image data in the imaging path. A halftone with a higher bit depth than the bit depth of the imaging path can be employed by generating a downsampled halftone or by shifting the image data by bits to match the halftone threshold.

[0056] For example, each level (l) of a multi-level halftone represents a droplet or dot size, where, in the case where the halftone includes small, medium, and large, level l = 0 represents a small droplet or dot. Thresholds are only required for non-zero droplet sizes. In roll-to-roll wide halftones, each nozzle / column k of the printhead has a set of halftone thresholds {h} for each level l of the multi-level halftone. k,l After iteration (i), the uniformity-compensated halftone threshold array is:

[0057] {h kl} i =U k,i (U k,i-1 (...U k,1 ({h kl}0)...)), where U k,i It is the inverse transfer function of nozzle k at iteration i. The uncalibrated initial halftone threshold array is composed of {h kl}0 is given. This leads to convergence towards a uniform response in the halftone image.

[0058] In an alternative embodiment, the uniformity compensation module 310 can directly apply the transfer function to the image data. In this embodiment, the uncalibrated halftone is not modified. Instead, the image data is transformed before halftone conversion. Therefore, a transfer function is generated for each nozzle, rather than an inverse transfer function, to generate the current cumulative transfer function. It is important to distinguish the cumulative transfer function TFCi(c) = TFi(TFi-1(...TF1(c)...)) determined in this way from the current transfer function TFi(c) at iteration i.

[0059] In other words, the cumulative transfer function is the composition of the transfer function determined by measurements at each iteration i. Additionally, this embodiment includes a uniformity compensation module 310 that uses halftone (e.g., a threshold array) and the transfer function applied to the image data to generate a calibration step chart.

[0060] In one embodiment, the same uncalibrated halftone is used for printing, and the cumulative transfer function is recalculated only to obtain the current cumulative transfer function after iteration i. Assume that the cumulative transfer function of nozzle k after iteration i is TFC. k,i Then the current cumulative transfer function of all nozzles is

[0061] TFC k,i =TF k,i (TF k,i-1 (…(TF k,1 )...))

[0062] Among them TF k,i This is the transfer function of nozzle k measured after iteration i. The initial transfer function TF is used. k,O This is typically a unit transfer function. In another embodiment, an initial transfer function derived based on engine calibration can be used. This leads to convergence toward a uniform response in a uniformly compensated halftone image, employing a cascaded transfer function instead of a uniformly calibrated halftone.

[0063] Figure 5 This is a flowchart illustrating one embodiment of a process 500 for performing uniformity compensation. Process 500 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software such as instructions that run on a processing device, or a combination thereof. In one embodiment, process 500 is executed by a uniformity compensation module 310.

[0064] At processing block 510, a halftone (e.g., a halftone design) is received. In the first iteration of this process, the halftone is an uncalibrated halftone. At processing block 520, a uniformity calibration step chart is generated by applying the halftone. This chart may have cross-rolled tapes with the same tinting level, ranging from zero to 100% tinting level across multiple steps. At processing block 530, the uniformity calibration chart is printed, and measurement data of the printed image, including OD measurement data, is received from the measurement chart. At decision block 540, a determination is made regarding whether the OD change is less than or equal to a predetermined threshold. If so, the OD change is less than or equal to the predetermined threshold, and a message indicating that uniform compensation for the halftone has been achieved is sent (processing block 580). As described above, this message may include the uniformly compensated halftone value. In some embodiments, a message indicating that the change is greater than the predetermined threshold (e.g., indicating that another iteration should be performed) may also be sent.

[0065] At processing block 550, nozzle measurement data is generated when the OD change is determined to be greater than a predetermined threshold. As described above, nozzle measurement data can be generated by interpolating the OD measurement data. At processing block 560, an inverse transfer function is generated for each nozzle to achieve the target OD response for each nozzle.

[0066] At processing block 570, a uniformity-compensated halftone is generated by modifying the thresholds in each column of the threshold array using the inverse transfer function of each nozzle. By performing these steps on a per-nozzle basis, improved uniformity compensation (e.g., more accurate, faster, less operator burden, etc.) can be achieved compared to conventional methods. In one embodiment, a uniformly-compensated halftone is generated for each droplet size designed for the halftone. This produces a current threshold array for printing or printing a uniformity calibration step chart.

[0067] In another embodiment, at processing block 570, a halftone with uniformity compensation for each primitive forming element is sent. In yet another embodiment, at processing block 570, a message indicating that halftones with uniformity compensation have not yet been implemented is sent (e.g., requesting modified print image measurement data corresponding to a modified uniformity calibration step chart with modified uniformity compensation halftones).

[0068] Subsequently, control returns to processing box 510, where the uniformity-compensated halftone is received as the updated halftone. This loop repeats multiple iterations required to satisfy the conditions of decision box 540. Once a threshold array satisfying the OD change criterion is generated, it can be used for all subsequent prints. The uniformity-compensation threshold array can be saved along with current conditions (such as paper type). Subsequent prints using the same identified paper type and / or halftone can employ the corresponding saved uniformity-compensation threshold array.

[0069] Figure 6 This is a flowchart illustrating another process 600 for performing uniformity compensation. In this process, a transfer function based on each nozzle of the cascaded process is employed. Process 600 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software such as instructions running on a processing device, or a combination thereof. In one embodiment, process 600 is executed by a uniformity compensation module 310.

[0070] At processing block 610, the transfer function is received. At processing block 620, a uniformity calibration step chart is generated by applying the transfer function. At processing block 630, the uniformity calibration chart is printed, and measurement data from the printed image of the measurement chart, including OD measurement data, is received. At decision block 640, a determination is made regarding whether the OD change is less than or equal to a predetermined threshold. If so, a message indicating that a set of transfer functions for uniformity compensation has been obtained is sent (processing block 680).

[0071] However, nozzle measurement data is generated when the OD change is determined to be greater than a predetermined threshold (processing block 650). At processing block 660, a transfer function is generated for each nozzle in the current iteration. At processing block 670, a refined set of cumulative transfer functions (cascaded transfer functions) is generated by modifying the nozzle's previous set of transfer functions.

[0072] In another embodiment, a refined cumulative transfer function set is sent at processing block 670. In yet another embodiment, at processing block 670, a message indicating halftones for which uniformity compensation has not yet been implemented is sent (e.g., requesting corrected print image measurement data corresponding to a corrected uniformity calibration step chart with corrected transfer functions applied to the print). Control then returns to processing block 610, where the process is repeated. Once a refined cumulative transfer function set that meets the OD variation criteria is generated, the cumulative transfer functions can be used for all subsequent prints. The uniformity-compensated cumulative transfer function set can be saved along with current conditions (such as paper type and halftone). Subsequent prints using the same identified paper type and / or halftone will utilize the corresponding saved refined cumulative transfer function set.

[0073] Note that the described cascaded refinement cumulative transfer function method can be employed in printing systems that do not have point-operated halftone rendering using threshold arrays. The described uniformity system employing a refined cascaded transfer function set can be employed in printers with implemented neighborhood halftone rendering (such as error diffusion).

[0074] The uniformity compensation module 310 performs the iterative uniformity compensation process described above for each primary ink color (e.g., CMYK) to minimize residual inconsistencies caused by nozzle interactions and printhead misalignment. Additionally, the uniformity compensation module 310 can perform uniformity compensation for secondary colors (e.g., red, green, and blue (RGB) colors). In such an embodiment, uniformity compensation is performed for each secondary color, which comprises two colors mixed according to a predetermined pair of primary color values ​​for each tinting location. As used herein, color is defined as a unique combination of primary ink tints, and tint is defined as the areal density of the primary ink.

[0075] refer to Figure 3 The calibration module 216 also includes missing neighbor function logic 320. According to one embodiment, the missing neighbor function logic 320 is implemented to calculate a missing neighbor function for the primary color and / or secondary color. For a uniformity compensation transfer function embodiment, the missing neighbor function includes a missing neighbor transfer function (MNTF) (e.g., one or more average missing neighbor transfer functions). For a uniformity compensation halftone embodiment, the missing neighbor function includes a missing neighbor threshold reduction function (e.g., one or more average missing neighbor threshold reduction functions). In this embodiment, the halftone design threshold of the neighbors of the missing primitive forming element 165 is reduced. Reducing the threshold produces a given droplet size with lower continuous-tone image pixel values. This, in turn, has the effect of darkening the adjacent regions of the missing primitive forming element 165 in the halftone design.

[0076] In one embodiment, the missing neighbor function logic 320 receives uniformity compensation data generated at the uniformity compensation module 310. As described above, the uniformity compensation data may include transfer function data associated with the transfer function for each nozzle for the primary color and / or for each nozzle for the secondary color in the transfer function embodiment, and uniformity compensation halftone data associated with the halftone threshold array for each nozzle for each primary color of ink in the halftone embodiment. The transfer function based on the secondary color is simplified to the set of transfer functions for the primary color.

[0077] In another embodiment, missing neighbor function logic 320 generates a missing neighbor step chart, which includes removing well-separated nozzles from the interior of each printhead segment in the original step chart (e.g., without providing nozzle emission instructions to spray ink onto the printing medium). Subsequently (e.g., at measurement module 190), the missing neighbor step chart is printed and measured to generate missing neighbor measurement data. Thus, missing neighbor correction measurement data is generated without using one or more of the multiple primitive forming elements in known locations.

[0078] In one embodiment, the uniformity compensation module 310 is implemented to generate missing neighbor uniformity compensation data (or missing neighbor correction data) based on missing neighbor measurement data. In such an embodiment, as referenced above... Figure 5 and Figure 6 The iterative uniformity process described is used to generate missing neighbor correction data. Therefore, the missing neighbor correction data includes the missing neighbor correction transfer function for each nozzle or a halftone design for missing neighbor correction (e.g., based on the inverse missing neighbor correction transfer function).

[0079] According to one embodiment, missing neighbor function logic 320 generates a missing neighbor function using missing neighbor correction data and uniformity compensation data. In such an embodiment, the missing neighbor function logic 320 derives the MNTF and MNTLF by comparing the missing neighbor correction data with the uniformity compensation data. Therefore, the MNTF maps uniformity compensation data values ​​to missing neighbor correction data values ​​for each level in the transfer function, while the MNTLF maps uniformity compensation data thresholds to missing neighbor data thresholds. In another embodiment, the MNTF mapping includes performing interpolation between uniformity compensation data values ​​and missing neighbor correction data values ​​to form the complete MNTF, while the MNTLF mapping includes performing interpolation between uniformity compensation data thresholds and missing neighbor data thresholds to form the complete MNTLF.

[0080] Figure 7 This is a flowchart illustrating one embodiment of a process 700 for generating an MNTF. Process 700 can be executed by processing logic, which may include hardware (e.g., circuitry, special-purpose logic, programmable logic, microcode, etc.), software such as instructions that run on a processing device, or a combination thereof. In one embodiment, process 700 is executed by missing neighbor function logic 320.

[0081] Process 700 begins at processing box 710, where the position values ​​of the column with missing neighbors are received. At processing box 720, the transfer function for each level (e.g., missing neighbor correction data value and uniformity correction data value) is read. At processing box 730, interpolation is performed between the missing neighbor correction data and uniformity correction data values ​​to generate the MNTF. At decision box 740, a determination is made regarding whether more additional columns with missing neighbors are available. If so, control returns to processing box 710, where another column with missing neighbors is received. Otherwise, the average of all MNTFs is calculated for each of the multiple printheads to generate the average MNTF for each of the multiple printheads (processing box 750). In another embodiment, the average MNTF may also be averaged across all printheads.

[0082] Figure 8This is a flowchart illustrating one embodiment of a process 800 for generating MNTLF. Process 800 can be executed by processing logic, which may include hardware (e.g., circuitry, special-purpose logic, programmable logic, microcode, etc.), software such as instructions that run on a processing device, or a combination thereof. In one embodiment, process 800 is executed by missing neighbor function logic 320.

[0083] Process 800 begins at processing box 810, where the position values ​​of columns with missing neighbors are received. At processing box 820, a threshold reduction function (e.g., missing neighbor correction threshold) is read for each level (e.g., uniformity correction threshold). Figure 9 The illustration shows one embodiment of the original and missing neighbor thresholds. At processing box 830, interpolation is performed between the missing neighbor correction threshold and the uniformity correction threshold to generate the MNTLF. At decision box 840, a determination is made regarding whether additional columns with missing neighbors are available. If so, control returns to processing box 810, where another column with missing neighbors is received. Otherwise, the average MNTLF is calculated for each printhead to generate an average MNTLF for each printhead (processing box 850). In another embodiment, the average MNTLF may also be averaged across all printheads.

[0084] Figure 10 This is a flowchart illustrating one embodiment of a missing neighbor process 1000. Process 1000 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software such as instructions that run on a processing device, or a combination thereof. In one embodiment, process 1000 is executed by missing neighbor function logic 320.

[0085] Process 1000 begins at processing box 1010, where uniformity compensation data is received. At processing box 1020, a missing neighbor step chart is generated. At processing box 1030, missing neighbor measurement data is received (e.g., after printing and measuring the missing neighbor step chart). At processing box 1040, missing neighbor correction data is generated.

[0086] At processing box 1050, as shown in the reference above. Figure 7 and Figure 8 The missing neighbor function is generated as discussed. At processing block 1060, the missing neighbor function (e.g., one or more average missing neighbor transfer functions, one or more average missing neighbor threshold reduction functions, etc.) is sent. In one embodiment, the missing neighbor function is sent along with the original uniformity compensation data (e.g., transfer functions and halftone design) to nozzle correction logic 168 included in printer 160.

[0087] refer to Figure 2 The print controller 140 includes nozzle analysis logic 230. In one embodiment, the nozzle analysis logic 230 receives measurement data (e.g., image scan data) from the print media 180 during print job production (e.g., via measurement module 190). In such an embodiment, the nozzle analysis logic 230 analyzes the image scan data during print production to detect ejection data associated with one or more defective (or missing) primitive forming elements 165. In another embodiment, the nozzle analysis logic 230 generates a list of defective nozzles including all primitive forming elements 165 identified as defective. Thus, each primitive forming element 165 identified as missing / defective is added to the list of defective nozzles. Once generated, the list of defective nozzles is sent to nozzle correction logic 168. In one embodiment, the list of defective nozzles is sent along with each bitmap 150 sent to the printer 160.

[0088] Figure 11 An embodiment of nozzle correction logic 168 is illustrated. Figure 11 As shown, the nozzle correction logic 168 includes a missing neighbor analysis engine 1110 and a missing neighbor processing logic 1120. The missing neighbor analysis engine 1110 receives a missing neighbor function and raw uniformity compensation data from the calibration module 216, and a list of defective nozzles from the nozzle analysis logic 230. During the printing process, the missing neighbor analysis engine 1110 uses the list of defective nozzles to analyze the primitive forming elements 165 in each column to determine whether the primitive forming element 165 is a neighbor of the missing / defective primitive forming element 165.

[0089] In one embodiment, the missing neighbor analysis engine 1110 determines whether primitive forming element 165 is a neighbor (e.g., left neighbor and / or right neighbor) of a missing / defective primitive forming element 165 indicated in the defective nozzle list (e.g., primitive forming element x = x' - 1, where x' = column number of the defective primitive forming element). In another embodiment, when it is determined that primitive forming element 165 is not a left neighbor of missing / defective primitive forming element 165, the missing neighbor analysis engine 1110 implements normal tone curves (e.g., tone curves associated with a uniformity compensation transfer function) and / or normal halftones (e.g., halftones associated with a uniformity compensation transfer function) to print bitmap data to a print medium via primitive forming element 165. However, when it is determined that primitive forming element 165 is a left neighbor of missing / defective primitive forming element 165, the missing neighbor processing logic 1120 performs missing neighbor processing using a missing neighbor function (e.g., MNTF or MNTLF).

[0090] According to one embodiment, missing neighbor processing logic 1120 performs missing neighbor processing by applying a missing neighbor halftone (e.g., via MNTLF) or correction (e.g., via MNTF) at the left adjacent neighbor primitive forming element (x) and / or the right adjacent neighbor primitive forming element (x+2) of the missing / defective primitive forming element (x'), while bypassing the processing of x'. In another embodiment, where the dot gain is such that there is a large amount of ink from the nearest neighbor, the two nearest neighbors on each side of the missing jet can be corrected. Subsequently, the process is repeated for each column, and for the row primitive coordinates (x, y) in the column.

[0091] Figure 12 This is a flowchart illustrating one embodiment of a nozzle correction process 1200 applying missing neighbor correction via MNTF. Process 1200 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software such as instructions running on a processing device, or a combination thereof. In one embodiment, process 1200 is executed by nozzle correction logic 168.

[0092] Process 1200 begins at processing box 1210, where a missing neighbor function and raw uniformity compensation data are received. At processing box 1220, a list of defective nozzles is received. At processing box 1230, primitive forming elements 165 (e.g., nozzles) are analyzed. At decision box 1240, it is determined whether a nozzle is a neighbor (e.g., left neighbor) of a missing / defective nozzle. If not, a normal tone curve is applied to print the bitmap data to the print media using the nozzle (processing box 1250). Otherwise, missing neighbor processing is performed using the MNTF associated with the nozzle (processing box 1260).

[0093] In one embodiment, MNTF is applied (or used) to print data (e.g., printing T) by cascading the nozzle's MNTF with a uniformity correction transfer function. MN (T x (g) Perform missing neighbor processing, where T MN It is the missing neighbor transitive function, T x is the uniformity correction transfer function, and g is the primitive value. As described above, missing neighbor processing is performed for the left and / or right neighbors of the missing / defective nozzle, while no data is applied by the defective nozzle. Once missing neighbor processing has been performed, a determination is made regarding whether there are more nozzles to analyze (decision box 1270). If yes, control returns to processing box 1230, where the next nozzle is analyzed. Otherwise, the process ends.

[0094] Figure 13This is a flowchart illustrating one embodiment of a nozzle correction process 1300 applying missing neighbor correction via MNTLF. Process 1300 may be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software such as instructions running on a processing device, or a combination thereof. In one embodiment, process 1300 is executed by nozzle correction logic 168.

[0095] Process 1300 begins at processing box 1310, where the missing neighbor function and raw uniformity compensation data are received. At processing box 1320, a list of defective nozzles is received. At processing box 1330, the nozzles are analyzed. At decision box 1340, a determination is made regarding whether a nozzle is the left neighbor of a missing / defective nozzle. If not, normal halftone is applied to print the bitmap data to the print media using the nozzle (processing box 1350). Otherwise, missing neighbor processing is performed using the MNTLF associated with the nozzle (processing box 1360).

[0096] In one embodiment, the MNTLF is used to perform missing neighbor processing by applying a threshold reduction function to a uniformity-corrected halftone design to generate a missing neighbor-corrected halftone design such that h' ijk =TLF(h ijk ), where h' ijk It is a halftone design lacking neighbor correction, and h ijk The halftone design is uniformly corrected. Subsequently, halftone tinting is performed using a missing neighbor correction halftone design. As described above, missing neighbor processing is performed for the left and / or right neighbors of the missing / defective nozzle, while no data is applied by the defective nozzle.

[0097] At decision box 1370, a determination is made regarding whether there are additional nozzles to be analyzed. If so, control returns to processing box 1330, where the next nozzle is analyzed. Otherwise, the process ends. In this embodiment, processes 1200 and 1300 are performed for each primary color. However, in other embodiments, processes 1200 and 1300 may also be performed for secondary colors.

[0098] Although shown as a component of print controller 140, other embodiments may feature a calibration module 216 included within a separate device or combination of devices communicatively coupled to print controller 140. For example, Figure 14 An embodiment of a calibration module 216 implemented in network 1400 is illustrated. Figure 14 As shown, the calibration module 216 is included in the computing system 1410 and sends the calibrated halftone 220 to the printing system 130 via the cloud network 1450.

[0099] Figure 15 The illustration shows a computer system 1500 on which a printing system 130, a computing system 1410, nozzle analysis logic 230, and / or calibration module 216 may be implemented. The computer system 1500 includes a system bus 1520 for transmitting information and a processor 1510 coupled to the bus 1520 for processing information.

[0100] Computer system 1500 also includes random access memory (RAM) or other dynamic storage device 1525 (referred to herein as main memory) coupled to bus 1520 for storing information and instructions to be executed by processor 1510. Main memory 1525 can also be used to store temporary variables or other intermediate information during instruction execution by processor 1510. Computer system 1500 may also include read-only memory (ROM) and / or other static storage devices 1526 coupled to bus 1520 for storing static information and instructions used by processor 1510.

[0101] Data storage device 1527 (such as a disk or optical disk) and its corresponding drive may also be coupled to computer system 1500 for storing information and instructions. Computer system 1500 may also be coupled to a second I / O bus 1550 via I / O interface 1530. Multiple I / O devices may be coupled to I / O bus 1550, including display device 1524, input devices (e.g., alphanumeric input device 1523 and / or cursor control device 1522). Communication device 1521 is used to access other computers (servers or clients). Communication device 1521 may include a modem, network interface card, or other well-known interface devices, such as interface devices for coupling to Ethernet, Token Ring, or other types of networks.

[0102] Embodiments of the present invention may include the various steps described above. These steps may be embodied in machine-executable instructions. These instructions may be used to cause a general-purpose or special-purpose processor to perform certain steps. Alternatively, these steps may be performed by specific hardware components containing hard-wired logic for performing the steps, or by any combination of programmed computer components and custom hardware components.

[0103] Elements of the present invention can also be provided as a machine-readable medium for storing machine-executable instructions. Machine-readable media may include, but are not limited to, floppy disks, optical disks, CD-ROMs and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnetic cards or optical cards, propagation media, or other types of media / machine-readable media suitable for storing electronic instructions. For example, the present invention can be downloaded as a computer program that can be transmitted from a remote computer (e.g., a server) to a requesting computer (e.g., a client) via a communication link (e.g., a modem or network connection) through data signals embodied in a carrier wave or other propagation medium.

[0104] The following terms and / or examples relate to other embodiments or examples. Details in the examples may be used anywhere in one or more embodiments. Various features of different embodiments or examples may be combined in various ways with some of the included features and others that are excluded to suit a variety of different applications. Examples may include, for instance, a device for performing actions of a method, the subject matter of at least one machine-readable medium including instructions that, when executed by a machine, cause the machine to perform actions of a method, or the operation of a device or system according to the embodiments and examples described herein.

[0105] Some embodiments relate to Example 1, which includes a system comprising a printing system including at least one physical memory device and one or more processors. The at least one physical memory device is used to store calibration logic. The one or more processors are coupled to the at least one physical memory device to perform the calibration logic to generate a uniformly compensated halftone design for each of a plurality of primitive forming elements, generate a missing neighbor corrected halftone design for each of the plurality of primitive forming elements, generate a missing neighbor threshold reduction function for each of the plurality of primitive forming elements based on the uniformly compensated halftone design and the missing neighbor corrected halftone design, and calculate the average of the missing neighbor threshold reduction function to generate an average missing neighbor threshold reduction function.

[0106] Example 2 includes the subject matter as described in Example 1, wherein generating a missing neighbor threshold reduction function for a primitive forming element includes mapping a data threshold associated with a halftone design for uniformity compensation of the primitive forming element to a data threshold associated with a halftone design for missing neighbor correction of the primitive forming element.

[0107] Example 3 includes the subject matter described in Examples 1 and 2, wherein the uniformity-compensated halftone design is generated based on the inverse transfer function of uniformity compensation, and the missing neighbor correction halftone design is generated based on the inverse transfer function of missing neighbor correction.

[0108] Example 4 includes the subject matter described in Examples 1-3, wherein the inverse transfer function for uniformity compensation is generated based on first printed image measurement data, and the inverse transfer function for missing neighbor correction is generated based on second printed image measurement data.

[0109] Example 5 includes the subject matter described in Examples 1-4, wherein the second printed image measurement data includes missing neighbor data based on data generated in the absence of one or more of the plurality of primitive forming elements.

[0110] Example 6 includes the subject matter described in Examples 1-5, wherein the calibration logic calculates the average of the missing neighbor threshold reduction function for each of the plurality of printheads to generate an average missing neighbor threshold reduction function for each of the plurality of printheads.

[0111] Example 7 includes the subject matter described in Examples 1-6, wherein the calibration logic sends the average missing neighbor threshold reduction function and the halftone design for uniformity compensation.

[0112] Example 8 includes the subject matter as described in Examples 1-7, and also includes a printing engine for receiving the missing neighbor threshold reduction function and the halftone design for uniformity compensation.

[0113] Example 9 includes the subject matter described in Examples 1-7, and further includes at least one physical memory device and one or more processors, the at least one physical memory device being used to store nozzle analysis logic, the one or more processors being coupled to the at least one physical memory device to execute the nozzle analysis logic to receive image scan data during the generation of a print job at the print engine, and to detect one or more defective primitive forming elements in the image scan data.

[0114] Example 10 includes the subject matter described in Examples 1-9, wherein the nozzle analysis logic generates a list including each of the detected primitive forming elements and sends the list to the printing engine.

[0115] Some embodiments relate to Example 11, which has at least one computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause the processors to generate a uniformly compensated halftone design for each of a plurality of primitive forming elements, generate a missing neighbor corrected halftone design for each of the plurality of primitive forming elements, generate a missing neighbor threshold reduction function for each of the plurality of primitive forming elements based on the uniformly compensated halftone design and the missing neighbor corrected halftone design, and calculate an average of the missing neighbor threshold reduction functions to generate an average missing neighbor threshold reduction function.

[0116] Example 12 includes the subject matter described in Example 11, wherein generating a missing neighbor threshold reduction function for a primitive forming element includes mapping a data threshold associated with a halftone design for uniformity compensation of the primitive forming element to a data threshold associated with a halftone design for missing neighbor correction of the primitive forming element.

[0117] Example 13 includes the subject matter described in Examples 11 and 12, wherein the uniformity-compensated halftone design is generated based on the inverse transfer function of uniformity compensation, and the missing neighbor correction halftone design is generated based on the inverse transfer function of missing neighbor correction.

[0118] Example 14 includes the subject matter described in Examples 10-13, wherein the inverse transfer function for uniformity compensation is generated based on first printed image measurement data, and the inverse transfer function for missing neighbor correction is generated based on second printed image measurement data.

[0119] Example 15 includes the subject matter described in Examples 10-14, wherein the second printed image measurement data includes missing neighbor data based on data generated in the absence of one or more of the plurality of primitive forming elements.

[0120] Example 16 includes the subject matter described in Examples 10-15, having instructions stored thereon that, when executed by one or more processors, also cause the processors to calculate an average of the missing neighbor threshold reduction function for each of a plurality of printheads, to generate an average missing neighbor threshold reduction function for each of the plurality of printheads.

[0121] Some embodiments relate to Example 17, which includes a method comprising generating a uniformly compensated halftone design for each of a plurality of primitive forming elements, generating a missing neighbor corrected halftone design for each of the plurality of primitive forming elements, generating a missing neighbor threshold reduction function for each of the plurality of primitive forming elements based on the uniformly compensated halftone design and the missing neighbor corrected halftone design, and calculating an average of the missing neighbor threshold reduction functions to generate an average missing neighbor threshold reduction function.

[0122] Example 18 includes the subject matter described in Example 17, wherein the uniformity-compensated halftone design is generated based on the inverse transfer function of uniformity compensation, and the missing neighbor correction halftone design is generated based on the inverse transfer function of missing neighbor correction.

[0123] Example 19 includes the subject matter described in Examples 17 and 18, wherein the calibration logic calculates the average of the missing neighbor threshold reduction function for each of the plurality of printheads to generate an average missing neighbor threshold reduction function for each of the plurality of printheads.

[0124] Example 20 includes the subject matter described in Examples 17-19, wherein the calibration logic sends the average missing neighbor threshold reduction function and the halftone design for uniformity compensation.

[0125] While many changes and modifications to the invention will undoubtedly become apparent to those skilled in the art after reading the foregoing description, it should be understood that any particular embodiment shown and described by way of illustration is by no means intended to be limiting. Therefore, the mention of details of various embodiments is not intended to limit the scope of the claims, which themselves only set forth those features deemed essential to the invention.

[0126] This application is based on and claims the benefit of priority to U.S. Patent Application No. US17 / 193935, filed March 5, 2021, the contents of which are incorporated herein by reference.

Claims

1. A printing system, comprising: At least one physical memory device, the at least one physical memory device being used to store calibration logic; as well as One or more processors, coupled to the at least one physical memory device, execute the calibration logic, thereby: For each of the multiple primitive forming elements, generate a halftone design with uniformity compensation; For each of the plurality of primitive forming elements, a halftone design with missing neighbor correction is generated; Based on the halftone design with uniformity compensation and the halftone design with missing neighbor correction, a missing neighbor threshold reduction function is generated for each of the plurality of primitive forming elements. as well as Calculate the average value of the missing neighbor threshold reduction function to generate the average missing neighbor threshold reduction function.

2. The printing system of claim 1, wherein generating a missing neighbor threshold reduction function for a primitive forming element comprises: The data threshold associated with the halftone design for uniformity compensation of the primitive forming element is mapped to the data threshold associated with the halftone design for missing neighbor correction of the primitive forming element.

3. The printing system according to claim 1, wherein the uniformity-compensated halftone design is generated based on the inverse transfer function of uniformity compensation, and the missing neighbor correction halftone design is generated based on the inverse transfer function of missing neighbor correction.

4. The printing system according to claim 3, wherein the inverse transfer function for uniformity compensation is generated based on first printed image measurement data, and the inverse transfer function for missing neighbor correction is generated based on second printed image measurement data.

5. The printing system of claim 1, wherein the calibration logic calculates the average of the missing neighbor threshold reduction function for each of the plurality of printheads to generate an average missing neighbor threshold reduction function for each of the plurality of printheads.

6. The printing system of claim 1, wherein the calibration logic sends the average missing neighbor threshold reduction function and the uniformity compensation halftone design.

7. The printing system of claim 6, further comprising a printing engine for receiving the missing neighbor threshold reduction function and the halftone design for uniformity compensation.

8. The printing system according to claim 7, further comprising: At least one physical memory device, the at least one physical memory device being used to store nozzle analysis logic; as well as One or more processors, coupled to the at least one physical memory device, execute the nozzle analysis logic, thereby: Image scan data is received during the generation of a print job at the print engine; as well as Detect one or more defective primitive forming elements in the image scan data.

9. The printing system of claim 8, wherein the nozzle analysis logic generates a list including each of the detected primitive forming elements and sends the list to the printing engine.

10. A printing method, comprising: For each of the multiple primitive forming elements, generate a halftone design with uniformity compensation; For each of the plurality of primitive forming elements, a halftone design with missing neighbor correction is generated; Based on the halftone design with uniformity compensation and the halftone design with missing neighbor correction, a missing neighbor threshold reduction function is generated for each of the plurality of primitive forming elements. as well as Calculate the average value of the missing neighbor threshold reduction function to generate the average missing neighbor threshold reduction function.

11. The printing method of claim 10, wherein the uniformity-compensated halftone design is generated based on the inverse transfer function of uniformity compensation, and the missing neighbor correction halftone design is generated based on the inverse transfer function of missing neighbor correction.

12. The printing method of claim 10, wherein the average of the missing neighbor threshold reduction function for each of the plurality of printheads is calculated by calibration logic to generate the average missing neighbor threshold reduction function for each of the plurality of printheads.

13. The printing method of claim 10, wherein the average missing neighbor threshold reduction function and the uniformity compensation halftone design are sent via calibration logic.

14. A computer-readable medium having instructions stored thereon, which, when executed by one or more processors, cause the processors to perform the printing method according to any one of claims 10-13.

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