JP2020026076A - Image processing device, image processing program and image forming device - Google Patents

Abstract

To suppress deterioration in correction effect at the time when an impact position of liquid droplets discharged from an adjacent nozzle adjacent to a non-discharging nozzle, in performing correction processing for making a white stripe generated by the non-discharge nozzle inconspicuous.SOLUTION: The image processing device comprises: a calculating part that calculates shift of an impact position of an adjacent nozzle from basic information indicating a predetermined impact position of liquid droplets discharged from the adjacent nozzle adjacent to a non-discharge nozzle from which liquid droplets are not discharged when forming an image onto a recording medium and position information about an impact position of the liquid droplets discharged from the adjacent nozzle, and calculates a correction value for correcting a pixel value of pixel corresponding to the adjacent nozzle using the calculated shift of the impact position; and a correcting part that corrects the pixle value of the pixel corresponding to the adjacent nozzle, using the correction value calculated by the calculating part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image processing device, an image processing program, and an image forming device.

  Patent Literature 1 discloses an image recording apparatus and method capable of realizing high-accuracy density correction (streak streak suppression) even when an unrecordable element such as a non-ejection nozzle occurs, and an image processing program useful for the correction processing. Has been described.

JP 2009-241271 A

  The present invention suppresses a decrease in the correction effect when a landing position of a droplet ejected from an adjacent nozzle adjacent to a non-ejection nozzle shifts when performing a correction to make white streaks generated by a non-ejection nozzle inconspicuous. I do.

  The image processing apparatus according to the first aspect is configured to basically indicate a predetermined landing position of a droplet ejected from an adjacent nozzle adjacent to a non-ejection nozzle to which no droplet is ejected when an image is formed on a recording medium. From the information and the position information of the landing position of the droplet ejected from the adjacent nozzle, the displacement of the landing position of the adjacent nozzle is calculated, and the displacement of the pixel corresponding to the adjacent nozzle is calculated using the displacement of the landing position. A calculating unit that calculates a correction value for correcting the pixel value; and a correcting unit that corrects a pixel value of a pixel corresponding to the adjacent nozzle using the correction value calculated by the calculating unit.

  The image processing apparatus according to a second aspect is the image processing apparatus according to the first aspect, wherein the calculation unit is configured to determine whether the landing position is shifted in a cross direction with respect to a conveyance direction of the recording medium. The correction value is calculated such that the correction intensity of the correction performed by the correction unit changes according to the direction of the correction.

  The image processing device according to a third aspect is the image processing device according to the second aspect, wherein the calculation unit is configured to determine the direction of the cross direction when the direction of the cross direction is a direction away from the ejection failure nozzle. The correction value is calculated such that the correction intensity is higher than when the direction is a direction approaching the non-ejection nozzle.

  An image processing device according to a fourth aspect is the image processing device according to the second or third aspect, wherein the calculating unit is configured to determine that the direction of the cross direction is a direction approaching the non-ejection nozzle. The correction value is calculated such that the correction intensity is weaker than when the direction of the cross direction is a direction away from the non-ejection nozzle.

  An image processing apparatus according to a fifth aspect is the image processing apparatus according to any one of the first to fourth aspects, wherein the calculation unit further performs the correction using a pixel value of a pixel corresponding to the adjacent nozzle. Calculate the value.

  An image processing apparatus according to a sixth aspect is the image processing apparatus according to any one of the first to fifth aspects, wherein the correction unit includes a plurality of correction information storing correction information regarding correction performed by the correction unit. The correspondence table to be used in the correction is determined from the table using the correction value calculated by the calculation unit, and the correction information of the determined correspondence table is used.

  An image processing device according to a seventh aspect is the image processing device according to any one of the first to fifth aspects, wherein the correction unit is configured to use a correspondence table in which correction information regarding correction performed by the correction unit is stored. Determining the correction information to be used in the correction, and correcting the pixel value of the pixel corresponding to the adjacent nozzle using the determined correction information and the correction value calculated by the calculation unit.

  An image processing apparatus according to an eighth aspect is the image processing apparatus according to any one of the first to seventh aspects, wherein the calculation unit calculates the correction value in consideration of landing interference.

  An image processing device according to a ninth aspect is the image processing device according to the eighth aspect, wherein the calculation unit is configured to use a non-permeable recording medium other than the non-permeable recording medium when the non-permeable recording medium is used. The correction value is calculated such that the correction intensity of the correction performed by the correction unit is higher than when the recording medium is used.

  An image processing apparatus according to a tenth aspect is the image processing apparatus according to the eighth or ninth aspect, wherein the calculation unit is adjacent to a first droplet, and the recording medium is disposed after the first droplet. The correction value is calculated such that the correction intensity of the correction performed by the correction unit is higher for the second droplet that lands on the liquid crystal panel than for the first liquid droplet.

  An image processing program according to an eleventh aspect causes a computer to function as the calculation unit and the correction unit of the image processing device according to the first to tenth aspects.

  An image forming apparatus according to a twelfth aspect includes the image processing apparatus according to any one of the first to tenth aspects, and an image forming unit that forms an image on which image processing has been performed by the image processing apparatus on the recording medium.

  According to the first aspect, in the case of performing correction for making white streaks generated by a non-discharge nozzle inconspicuous, a correction effect when a landing position of a droplet discharged from an adjacent nozzle adjacent to the non-discharge nozzle is shifted. Can be suppressed.

  According to the second aspect, the correction is performed with the correction strength corresponding to the displacement of the landing position, compared to the configuration in which the correction strength is uniformly changed in one direction regardless of the direction of the cross direction in which the displacement of the landing position occurs. It can be carried out.

  According to the third aspect, when the direction of the cross direction is a direction away from the non-discharge nozzle, a correction value with a lower correction strength is calculated than when the direction of the cross direction is a direction approaching the non-discharge nozzle. Compared with the configuration, it is possible to suppress the white streaks remaining after the correction.

  According to the fourth aspect, when the direction of the cross direction is a direction approaching the non-discharge nozzle, a correction value having a higher correction strength is calculated than when the direction of the cross direction is a direction away from the non-discharge nozzle. As compared with the configuration, it is possible to suppress the occurrence of black streaks after the correction.

  According to the fifth aspect, the correction can be performed with the correction intensity corresponding to the pixel value of the pixel corresponding to the adjacent nozzle, as compared with a configuration in which the pixel value of the pixel corresponding to the adjacent nozzle is not used for calculating the correction value. it can.

  According to the sixth aspect, each time an image is formed on a pixel corresponding to an adjacent nozzle, an image is easily formed on a pixel corresponding to an adjacent nozzle as compared with a configuration in which a pixel value of a pixel corresponding to an adjacent nozzle is calculated. it can.

  According to the seventh aspect, it is possible to accurately correct the pixel value of the pixel corresponding to the adjacent nozzle, as compared with a configuration in which correction is performed with a common correction strength within a fixed correction value range.

  According to the eighth aspect, even when landing interference occurs, white streaks generated by non-ejection nozzles can be made less noticeable than in a configuration in which landing interference is not considered in the calculation of a correction value.

  According to the ninth aspect, when a non-permeable recording medium is used, a correction value with a smaller correction strength is calculated than when a recording medium other than a non-permeable recording medium is used. Even when a permeable recording medium is used, white streaks generated by non-ejection nozzles can be made inconspicuous with high accuracy.

  According to the tenth aspect, when the second droplet becomes the correction droplet, the correction intensity is lower than that when the first droplet becomes the correction droplet with respect to the second droplet. Compared to a configuration in which a correction value is calculated, white streaks generated by a non-ejection nozzle can be made less noticeable.

  According to the eleventh aspect, when performing correction to make white streaks generated by a non-discharge nozzle inconspicuous, a correction effect when a landing position of a droplet discharged from an adjacent nozzle adjacent to the non-discharge nozzle is shifted. Can be suppressed.

  According to the twelfth aspect, when performing correction to make white streaks generated by a non-discharge nozzle inconspicuous, a correction effect when a landing position of a droplet discharged from an adjacent nozzle adjacent to the non-discharge nozzle is shifted Can be suppressed.

FIG. 1 is a diagram illustrating an example of a configuration of an image forming apparatus according to a first embodiment. FIG. 3 is a block diagram illustrating a configuration of a control unit and the like according to the first embodiment. FIG. 4 is a diagram illustrating an example of a displacement of a landing position according to the first embodiment. FIG. 4 is a diagram illustrating an example of a displacement of a landing position according to the first embodiment. FIG. 4 is a diagram illustrating an example of a displacement of a landing position according to the first embodiment. FIG. 4 is a diagram illustrating an example of an original data table according to the first embodiment. FIG. 5 is a diagram illustrating an example of an adjustment value table according to the first embodiment. FIG. 5 is a diagram illustrating an example of an adjustment value table according to the first embodiment. FIG. 5 is a diagram illustrating an example of an adjustment value table according to the first embodiment. FIG. 5 is a diagram illustrating an example of an adjustment value table according to the first embodiment. FIG. 4 is a diagram illustrating an example of a correction table according to the first embodiment. FIG. 4 is a diagram illustrating an example of a correction table according to the first embodiment. FIG. 4 is a diagram illustrating an example of a correction table according to the first embodiment. FIG. 4 is a diagram illustrating an example of a correction table according to the first embodiment. FIG. 4 is a diagram illustrating an example of a correction table according to the first embodiment. FIG. 14 is a diagram illustrating an example of a correction table according to the second embodiment.

  Hereinafter, the present embodiment will be described with reference to the drawings. In the present embodiment, an example in which the image processing apparatus according to the present invention is applied to an inkjet image forming apparatus 10 will be described.

(First embodiment)
First, the configuration of the image forming apparatus 10 will be described.
As shown in FIG. 1, the image forming apparatus 10 includes a head unit 26, a paper feed roll 22, a take-up roll 24, a control unit 50, a drying unit 30, and an image reading unit 40.

  The head unit 26 forms an image on the continuous paper P by discharging ink droplets as droplets on a continuous paper (roll paper) P as a recording medium. The head unit 26 is an example of an image forming unit. The head unit 26 includes an inkjet head 12K that forms a K (black) color image, an inkjet head 12C that forms a C (cyan) color image, and an inkjet head 12M that forms an M (magenta) color image. , Y (yellow) color image.

  The inkjet heads 12 are arranged along the transport direction S of the continuous paper P in the order of K → C → M → Y. The order in which the inkjet heads 12 are arranged is an example, and is not limited to the above order. In the following description, when C, M, Y, and K are not distinguished, C, M, Y, and K attached to the reference numerals are omitted. The image forming apparatus 10 according to the first embodiment is of a so-called single-pass type, and printing is performed by the inkjet head 12 passing each position of the continuous paper P only once. However, the image forming apparatus 10 is not limited to the single pass system.

  Here, in the first embodiment, in order for the control unit 50 to identify the nozzle of each head unit 26, the nozzle of each head unit 26 is assigned a nozzle number in order from 1, 2,. ing. In the first embodiment, the remainder obtained by dividing the nozzle number by 4 corresponds to an identification number described later. For example, when the nozzle number is “5”, the identification number is “No. 1” which is the remainder obtained by dividing the nozzle number by 4, and when the nozzle number is “6”, the remainder is obtained by dividing the nozzle number by 4. No. 2 ".

  The paper feed roll 22 is rotatably supported by a frame member (not shown). The continuous paper P is wound around the paper feed roll 22. Then, the paper feed roll 22 supplies the continuous paper P to the head unit 26 by rotating clockwise in FIG.

  The take-up roll 24 is rotatably supported by a frame member (not shown). Then, the take-up roll 24 receives a rotational force from a motor (not shown) and rotates clockwise as viewed from the front in FIG. 1, so that the continuous paper P is taken up. Conveyed.

  The control unit 50 controls the operation of the image forming apparatus 10. Details of the control unit 50 will be described later.

  The drying unit 30 is disposed downstream of the head unit 26 in the transport direction S. The drying unit 30 irradiates the continuous paper P with a heat source (light) and dries the ink droplets ejected on the continuous paper P due to heat generation depending on the heat source (light). The purpose is to fix the image to P.

  The image reading unit 40 is disposed downstream of the drying unit 30 in the transport direction S and upstream of the winding roll 24 in the transport direction S. The image reading section 40 is also called an ILS (In Line Sensor) and reads an image recorded on a continuous paper P. The image reading unit 40 is provided with, for example, a line sensor in a cross direction T with respect to the transport direction S, and performs reading with the line sensor in accordance with the transport of the continuous paper P, so that the image is recorded on the continuous paper P. Get two-dimensional image information. Then, the image reading unit 40 transmits the acquired image information to the control unit 50.

The image forming apparatus 10 configured as described above operates as follows.
First, the take-up roll 24 is rotated clockwise by a motor (not shown) in a front view of FIG. Thereby, the continuous paper P supplied from the paper feed roll 22 is transported along the transport direction S by applying tension in the transport direction S. Thereafter, ink droplets are ejected from the continuous paper P by the head unit 26 to form an image. The drying unit 30 dries the ink droplets ejected on the continuous paper P, so that the image is fixed on the continuous paper P. The image recorded on the continuous paper P is read by the image reading unit 40 and transmitted to the control unit 50 as two-dimensional image information.

Next, the control unit 50 and a configuration connected to the control unit 50 will be described.
As shown in FIG. 2, the control unit 50 is connected to a CPU 51 (Central Processing Unit), a ROM 54 (Read Only Memory), a RAM 55 (Random Access Memory), and an input / output interface (I / O 56) via a bus. ing.

  Various programs to be executed by the CPU 51 are stored in the ROM 54. The various programs include at least an image processing program for causing a computer to function as a calculation unit 52 and a correction unit 53 described below. Then, the CPU 51 executes various programs by reading various programs from the ROM 54 and developing the programs in the RAM 55. The image processing program may be installed in the image forming apparatus 10 in advance, or may be stored in a non-volatile storage medium, or distributed via a network, and provided to the image forming apparatus 10. It may be installed as appropriate. Examples of the non-volatile storage medium include a CD-ROM, a magneto-optical disk, an HDD, a DVD-ROM, a flash memory, a memory card, and the like.

  The communication unit 60, the nonvolatile memory 62, the head unit 26, the drying unit 30, and the image reading unit 40 are connected to the I / O 56.

  The communication unit 60 is an interface through which a terminal device such as a personal computer (not shown) and the image forming apparatus 10 perform data communication with each other.

  The nonvolatile memory 62 includes an original data table (see FIG. 6) in which output pixel values serving as original data for generating output pixel values to be stored in a correction table described later, and an output pixel value serving as original data. An adjustment value table (see FIGS. 7 to 10) in which adjustment values to be added to are stored, and a plurality of correction tables (see FIGS. 11 to 15) are stored. The correction table is an example of a correspondence table. The details of the original data table, the adjustment value table, and the correction table will be described later.

  Here, in the image forming apparatus 10, when an image is formed on the continuous paper P, for example, ink droplets are not ejected due to clogging of the nozzle of the head unit 26, and the transport direction S of the continuous paper P , White streaks may occur continuously. Hereinafter, a nozzle of the head unit 26 from which an ink droplet is not ejected when an image is formed on the continuous paper P is referred to as a “non-ejection nozzle”.

  Then, the CPU 51 of the control unit 50 forms an image using an output pixel value obtained by changing an input pixel value of a pixel corresponding to an adjacent nozzle adjacent to the non-ejection nozzle in order to reduce the visibility of the white streak. It functions as a calculation unit 52 and a correction unit 53 for performing the above. Hereinafter, changing an input pixel value of a pixel corresponding to an adjacent nozzle to generate a corresponding output pixel value is referred to as “correction”.

Next, details of the calculation unit 52 and the correction unit 53 in which the CPU 51 of the control unit 50 functions will be described.
First, the calculation unit 52 will be described.

  The calculation unit 52 calculates the displacement of the landing position of the adjacent nozzle adjacent to the non-ejection nozzle. The “deviation of the landing position” means a deviation amount from a design ideal landing position when there is no discharge abnormality. The unit of the actual measurement value of the “landing position shift” is μm, but in the following, the unit after the numerical value is omitted, and “+” or “−” is added before the numerical value. . How to add “+” and “−” will be described later.

  The calculation unit 52 calculates the displacement of the landing position of the adjacent nozzle in the ink droplet information acquisition processing for acquiring information on the ink droplet ejected by the head unit 26. This ink droplet information acquisition process is controlled by the control unit 50, and is executed, for example, when the image forming apparatus 10 is manufactured (shipped). The execution timing of the ink droplet information acquisition process is not limited to this, and may be performed when a user performs an operation on the image forming apparatus 10 or when a preset execution timing of the ink droplet information acquisition process is reached. Good.

  In the ink droplet information acquisition processing, first, the head unit 26 forms an image of a print pattern (hereinafter, referred to as a “test pattern”) in which ideal landing positions of ink droplets are predetermined. The test pattern image data is stored in the ROM 54 of the control unit 50.

  Next, in the ink droplet information acquisition process, the image reading unit 40 detects a non-ejection nozzle based on a print result of the test pattern. Specifically, the image reading unit 40 measures the density information on the density of the ink droplet from the position information of the landing position of the ink droplet actually ejected by the head unit 26, and determines the nozzle from which the ink droplet has not been ejected as “ It is detected as a “non-discharge nozzle”.

  In the ink droplet information acquisition process, after the non-ejection nozzle is detected by the image reading unit 40, the calculation unit 52 compares the image data of the test pattern with the actual landing position information to determine the deviation of the landing position of the adjacent nozzle. calculate. Note that the ink droplet information acquisition process ends based on the calculation unit 52 calculating the deviation of the landing position of the adjacent nozzle. The image data of the test pattern is an example of the basic information.

  When the landing position shifts in the cross direction T with respect to the transport direction S, the calculation unit 52 changes the correction value indicating the degree of correction performed by the correction unit 53 according to the direction of the cross direction T. Is calculated. When it is necessary to distinguish one side and the other side in the cross direction T, the right side of the continuous paper P shown in FIG. 3 is described as + T side, and the left side is described as −T side.

  Specifically, as shown in FIG. 3, the calculation unit 52 calculates the landing position deviation by a positive number when the landing position deviation of the adjacent nozzle occurs on the + T side with respect to the continuous paper P, If the landing position shift of the adjacent nozzle occurs on the −T side with respect to the continuous paper P, the landing position shift is calculated with a negative number.

  Further, the calculation unit 52 calculates a correction value for correcting the input pixel value of the pixel corresponding to the adjacent nozzle using the calculated landing position shift.

  Specifically, the calculation unit 52 corrects the difference by subtracting "the displacement of the landing position of the adjacent nozzle on the -T side of the non-discharge nozzle" from the "displacement of the landing position of the adjacent nozzle on the + T side of the non-discharge nozzle". Calculate the value.

  Here, when the direction of the cross direction T in which the landing position of the adjacent nozzle has shifted is a direction away from the non-discharge nozzle, the calculation unit 52 determines that the direction of the cross direction T is a direction approaching the non-discharge nozzle. The correction value is calculated so that the correction intensity is higher than in the case. Further, the calculation unit 52 determines that the direction of the cross direction T is a direction away from the non-discharge nozzle when the direction of the cross direction T in which the landing position of the adjacent nozzle has shifted is a direction approaching the non-discharge nozzle. The correction value is calculated so that the correction strength becomes weaker than that of.

  Hereinafter, a flow in which the calculation unit 52 calculates the correction value will be described with reference to FIGS.

  3 to 5, circles shown by broken lines conceptually show ink droplets that were not ejected from the non-ejection nozzles, and circles shown by solid lines show a part of ink droplets ejected from the adjacent nozzles. This is shown conceptually.

  3 to 5, a broken line extending from the vicinity of the center of the continuous paper P in the cross direction T along the transport direction S is an ideal landing position of an ink droplet not ejected from the non-ejection nozzle. The landing position X is conceptually shown.

  Similarly, a dashed line extending along the transport direction S on the + T side of the ideal landing position X indicates the ideal landing position Y which is the ideal landing position of the ink droplet ejected from the adjacent nozzle on the + T side of the non-ejection nozzle. This is shown conceptually. A dashed line extending along the transport direction S on the −T side of the ideal landing position X indicates an ideal landing position Z that is an ideal landing position of an ink droplet ejected from an adjacent nozzle on the −T side of the non-ejection nozzle. Is shown in

  Further, in FIGS. 3 to 5, the two-dot chain line extending along the transport direction S is the actual landing position of the ink droplet ejected from the adjacent nozzle on the + T side or the −T side of the non-ejection nozzle. The position Y 'or the actual landing position Z' is conceptually shown. The distance in the intersecting direction T between the ideal impact position Y and the actual impact position Y ′ and the distance in the intersecting direction T between the ideal impact position Z and the actual impact position Z ′ are deviations of the impact position. The correction value is a value obtained by subtracting "the displacement of the landing position of the adjacent nozzle on the -T side of the non-ejection nozzle" from the "displacement of the landing position of the adjacent nozzle on the + T side of the nozzle".

  In the example shown in FIG. 3, the actual landing position Y 'is shifted from the ideal landing position Y to the + T side, and the calculation unit 52 calculates the shift of the landing position as "+2". The actual landing position Z 'is shifted from the ideal landing position Z to the -T side, and the calculation unit 52 calculates the shift of the landing position as "-1.5". Then, the calculation unit 52 calculates the difference between the landing position of the adjacent nozzle on the −T side of the non-ejection nozzle and “−1.5” from the difference of the landing position of the adjacent nozzle on the + T side of the non-ejection nozzle. ”To calculate a correction value“ +3.5 ”(+2 − (− 1.5) = + 3.5).

  In the example shown in FIG. 4, the actual landing position Y 'is shifted from the ideal landing position Y to the -T side, and the calculation unit 52 calculates the shift of the landing position as "-2". Further, the actual landing position Z 'is shifted from the ideal landing position Z to the + T side, and the calculation unit 52 calculates the shift of the landing position as "+1.5". Then, the calculation unit 52 calculates the difference between the landing position of the adjacent nozzle on the + T side of the non-ejection nozzle and the displacement of the landing position of the adjacent nozzle on the −T side of the non-ejection nozzle from “−1.5”. Is subtracted to calculate a correction value “−3.5” (−2 − (+ 1.5) = − 3.5).

  In the example shown in FIG. 5, the actual landing position Y 'is shifted from the ideal landing position Y to the -T side, and the calculation unit 52 calculates the shift of the landing position as "-2". The actual landing position Z 'is shifted from the ideal landing position Z to the -T side, and the calculation unit 52 calculates the shift of the landing position as "-1.5". Then, the calculating unit 52 calculates the difference between the landing position of the adjacent nozzle on the −T side of the non-ejection nozzle and “−1. The correction value “−0.5” is calculated by subtracting “5” (−2 − (− 1.5) = − 0.5).

  Although details of the correction table will be described later, five types of correction strength in the first embodiment are provided, which are “weak”, “slightly weak”, “normal”, “slightly strong”, and “strongly”. In the first embodiment, a correction table with a higher correction intensity is used as the positive value of the correction value increases, and a correction table with a lower correction intensity is used as the negative value of the correction value increases. Has become. Therefore, the example shown in FIG. 3 in which the displacement of the landing position occurs in the direction away from the non-discharge nozzle has a stronger correction strength than the example shown in FIG. 4 in which the displacement of the landing position occurs in the direction approaching the non-discharge nozzle. The correction value is calculated as follows.

  In the first embodiment, among the ink droplets ejected from the adjacent nozzles, the number of large droplets larger than the small droplets is increased as the correction intensity becomes higher. Further, in the first embodiment, the number of large droplets larger than the small droplets among the ink droplets discharged from the adjacent nozzles is reduced as the correction intensity becomes weaker. Therefore, in the first embodiment, as the correction intensity increases, the density around the non-ejection nozzle increases, and as the correction intensity decreases, the density around the non-ejection nozzle decreases.

  In the first embodiment, the correction value calculated by the calculation unit 52 is “weak” when “less than -4”, “slightly weak” when “more than -4 and less than −1”, and “1 or more”. The case of "less than +2" corresponds to a correction table of "normal", the case of "+2 or more and less than +5" corresponds to a correction table of "slightly strong", and the case of "+5 or more" corresponds to a correction table of "strong".

Next, the correction unit 53 will be described.
The correction unit 53 corrects the input pixel value of the pixel corresponding to the adjacent nozzle using the correction value calculated by the calculation unit 52.

  Specifically, the correction unit 53 generates an output pixel value corresponding to the input pixel value stored in each correction table, using the original data table and the adjustment value table stored in the nonvolatile memory 62.

The original data table shown in FIG. 6 is a table in which the output pixel values of the pixels corresponding to the adjacent nozzles in a case where the displacement of the landing position is not considered.
There are four types of original data tables corresponding to the colors (C, M, Y, K) of ink droplets. Specifically, FIG. 6A is for C (cyan), FIG. 6B is for M (magenta), FIG. 6C is for Y (yellow), and FIG. ) Is an original data table.

  In each of the original data tables, the output pixel values of the pixels corresponding to the adjacent nozzles when the displacement of the landing position is not taken into consideration are stored in correspondence with the input pixel values. More specifically, the output pixel values correspond to four types of identification numbers (0, 0) corresponding to each of the first-struck ink droplet and the second-struck ink droplet that lands on the continuous paper P after the first-struck ink droplet. No. 1, No. 2, No. 3, and No. 3). The odd identification numbers of “No. 1” and “No. 3” correspond to the ink droplets of the first ejection, and the even identification numbers of “No. 0” and “No. 2” correspond to the ink droplets of the second ejection. It corresponds. The first ink droplet is an example of a first droplet, and the second ink droplet is an example of a second droplet.

As described above, since the output pixel values of the pixels corresponding to the adjacent nozzles are stored in the original data table, by forming an image on the continuous paper P using the output pixel values, It is also possible to make the white streaks generated by the inconspicuous. However, the output pixel values stored in the original data table do not take into account the deviation of the landing position. Therefore, it is desirable to consider the deviation of the landing position using the adjustment values stored in the following adjustment value table.
Therefore, the correction unit 53 determines the adjustment value stored in the adjustment value table using the correction value calculated by the calculation unit 52, and adds the determined adjustment value to the output pixel value stored in the original data table. By doing so, an output pixel value is generated in consideration of the deviation of the landing position.

  The adjustment value tables shown in FIGS. 7 to 10 are tables storing adjustment values for generating output pixel values of pixels corresponding to adjacent nozzles in consideration of the displacement of the landing position. There are three types of adjustment values: “0”, “negative number”, and “positive number”.

  There are four types of adjustment value tables corresponding to the colors (C, M, Y, K) of ink droplets. 7 is an adjustment value table for C (cyan), FIG. 8 is an adjustment value table for M (magenta), FIG. 9 is an adjustment value table for Y (yellow), and FIG. 10 is an adjustment value table for K (black).

  The adjustment value table for each color of the ink droplet further includes four types of tables corresponding to each identification number (0, 1, 2, 3). As described above, there are four types of adjustment value tables corresponding to the colors (C, M, Y, and K) of ink droplets, and each of the identification numbers (No. 0) is included in the four types of adjustment value tables. , No. 1, No. 2, and No. 3).

  Each adjustment value table stores an adjustment value corresponding to an input pixel value of a pixel corresponding to an adjacent nozzle. Specifically, the adjustment values are stored separately for each of the five types of correction strength (weak, slightly weak, normal, slightly strong, strong).

  For example, as shown in FIG. 7A, “0” or “negative number (−4 or −2)” is stored as an adjustment value corresponding to “correction intensity: weak” and “correction intensity: slightly weak”. ing. Also, “0” is stored as an adjustment value corresponding to “correction intensity: normal”. Further, “0” or “positive number (2 or 4)” is stored as an adjustment value corresponding to “correction intensity: somewhat high” and “correction intensity: high”.

  Therefore, the correction unit 53 generates a larger output pixel value of the pixel corresponding to the adjacent nozzle as the correction strength goes from “weak” to “strong”, and as the correction strength goes from “strong” to “weak”, It can be said that the output pixel value of the pixel corresponding to the adjacent nozzle is generated small.

  The correction tables shown in FIGS. 11 to 15 are output pixel values (hereinafter, referred to as “hereafter”) that are generated by the correction unit 53 by adding the adjustment values to the output pixel values stored in the original data table and that consider the deviation of the landing position. This is a table in which “corrected output pixel values” are stored.

  The correction table has five correction levels of “correction intensity: weak”, “correction intensity: slightly low”, “correction intensity: normal”, “correction intensity: slightly high”, and “correction intensity: high” according to the correction intensity. Types are provided. Specifically, FIG. 11 is for “correction intensity: weak”, FIG. 12 is for “correction intensity: somewhat weak”, FIG. 13 is for “correction intensity: normal”, and FIG. 14 is for “correction intensity: somewhat strong”. FIG. 15 is a correction table for “correction intensity: strong”.

  Each correction table stores the corrected output pixel value corresponding to the input pixel value of the pixel corresponding to the adjacent nozzle. Specifically, the output pixel values are stored separately for each color (C, M, Y, K) of the ink droplet. The corrected output pixel values stored in the correction table include those having the same input pixel value and output pixel value, those having the output pixel value larger than the input pixel value, and those having the output pixel value equal to the input pixel value. Some are smaller than. The output pixel value after the correction is an example of the correction information.

  In the correction table, the stored corrected output pixel value differs for each color (C, M, Y, K) of the ink droplet. For example, as shown in FIG. 11B, when the input pixel value is 190, the output pixel value of C (cyan) is “193”, and the output pixel value of M (magenta) is “189”. , Y (yellow) is “192”, and the output pixel value of K (black) is “188”.

Further, the correction table of each correction intensity is further divided into four types of tables corresponding to respective identification numbers (0, 1, 2, 3).
As described above, in the first embodiment, there are five types of correction tables according to the strength of the correction intensity. There are four types of correction tables corresponding to each of.

  Hereinafter, as an example, the correction unit 53 outputs the C (cyan) output pixel value corresponding to the input pixel value “5” in the correction table of “correction intensity: weak” and “0” (see FIG. 11A). The flow of generating “8” will be described.

  First, the correction unit 53 determines, from the original data table of the ink droplet of C (cyan) shown in FIG. 6A, the output pixel value “ 8 "is read. In addition, the correction unit 53 adjusts the adjustment value corresponding to the correction table of “correction intensity: weak” in the case of the input pixel value “5” from the adjustment value table of the C (cyan) ink droplet illustrated in FIG. Read "0". After that, the correction unit 53 sets the value “8” obtained by adding the adjustment value “0” to the output pixel value “8” read as described above to “correction intensity: weak” and “number 0” shown in FIG. Is stored in the area of the output pixel value of C (cyan) corresponding to the input pixel value “5” in the correction table of FIG. As a result, the corrected output pixel value “8” is stored in the C (cyan) output pixel value area.

  Then, the correction unit 53 generates the corrected output pixel values stored in each correction table by repeatedly performing the above processing.

  In addition, the correction unit 53 determines a correction table to be used in the correction from the five types of correction tables corresponding to the strength of the correction intensity, using the correction value calculated by the calculation unit 52. Then, the correcting unit 53 causes the head unit 26 to form an image using the corresponding corrected output pixel value from the determined correction table.

  First, the correction unit 53 is “weak” when the correction value calculated by the calculation unit 52 is “−7 or more and less than −4”, and “slightly weak” when the correction value is “−4 or more and less than −1”. The correction table is “normal” for “−1 or more and less than +2”, “slightly strong” for “+2 or more and less than +5”, and “strong” for “+5 or more and less than +8”. To decide. When the correction value is smaller than “−7”, the correction unit 53 determines a correction table of “correction intensity: weak”, and when the correction value is larger than “+8”, “correction intensity: weak”. The correction table may be determined to be “strong” or the correction table may not be determined as an error.

For example, when the correction value calculated by the calculation unit 52 is “−5”, the correction unit 53 determines a correction table of “correction intensity: weak”, and outputs the corrected output pixel stored in the correction table. The head unit 26 forms an image using the values.
Hereinafter, a case will be described as an example where the nozzle (nozzle number “6”) of the head unit 26 that ejects the ink droplet of the later ejection becomes a non-ejection nozzle and the ink droplet of the preceding ejection becomes a correction droplet.

  The correction unit 53 converts the correction table corresponding to the adjacent nozzle (nozzle number “5”) on the + T side of the non-ejection nozzle (nozzle number “6”) into the “No. 1” correction table shown in FIG. Set. Similarly, the correction unit 53 stores the correction table corresponding to the adjacent nozzle (nozzle number “7”) on the −T side of the non-ejection nozzle (nozzle number “6”) as “No. 3” shown in FIG. Is set in the correction table.

  When the input pixel value is 190, the head unit 26 sets the output pixel values of the adjacent nozzles (nozzle number “5”) to C: 193, M: 189, and Y: 192, K: 188, an image is formed. Similarly, when the input pixel value is 190, the head unit 26 sets the output pixel values of the adjacent nozzles (nozzle number “7”) to C: 197, M: 189, and Y as shown in FIG. : 196, K: 188 to form an image.

(Operation and Effect of First Embodiment)
The calculation unit 52 calculates a correction value for correcting the input pixel value of the pixel corresponding to the adjacent nozzle using the displacement of the landing position, and the correction unit 53 uses the correction value calculated by the calculation unit 52. The input pixel value of the pixel corresponding to the adjacent nozzle is corrected.

  That is, in the first embodiment, when correcting the input pixel value of the pixel corresponding to the adjacent nozzle, the displacement of the landing position is considered. For example, when the landing positions of the adjacent nozzles on the + T side and the −T side of the non-ejection nozzle are shifted in a direction away from the non-ejection nozzle, the calculation unit 52 calculates the correction value as a positive number. In the first embodiment, a correction table having a higher correction intensity is used as the positive value of the correction value increases, and the density around the non-ejection nozzle can be increased. Accordingly, in the first embodiment, for example, even if the landing positions of the adjacent nozzles on the + T side and the −T side of the non-ejection nozzle are shifted in a direction away from the non-ejection nozzle, the deviation of the landing position is considered. Thus, the density around the non-ejection nozzle can be adjusted.

  Therefore, according to the first embodiment, when performing correction to make the white streak generated by the non-ejection nozzle inconspicuous, when the landing position of the ink droplet ejected from the adjacent nozzle adjacent to the non-ejection nozzle is shifted. Can be prevented from lowering the correction effect.

  The calculation unit 52 calculates a correction value such that the correction strength of the correction performed by the correction unit 53 changes in accordance with the direction of the cross direction T when the landing position shifts in the cross direction T with respect to the transport direction S. .

  Specifically, the calculation unit 52 has a stronger correction strength when the landing position of the adjacent nozzle is shifted in the direction away from the non-ejection nozzle, as compared with the case where the landing position of the adjacent nozzle is not shifted. The correction value is calculated so as to be as follows. Further, the calculation unit 52 performs correction so that the correction strength becomes weaker when the landing position of the adjacent nozzle is shifted in a direction approaching the non-ejection nozzle, as compared with the case where the landing position of the adjacent nozzle is not shifted. Calculate the value.

  Therefore, according to the first embodiment, regardless of the direction of the intersecting direction T in which the displacement of the landing position occurs, the correction according to the displacement of the landing position is compared with the configuration in which the correction strength is uniformly changed in one direction. Correction can be made by intensity.

  Further, in the first embodiment, for example, even if the landing positions of the adjacent nozzles on the + T side and the −T side of the non-ejection nozzle are shifted in the direction away from the non-ejection nozzle, the deviation of the landing position is considered. By increasing the density around the non-ejection nozzle, a shift in the landing position is dealt with. Thus, in the first embodiment, even if the landing position of the adjacent nozzle shifts in the direction away from the non-ejection nozzle, the white streak generated by the non-ejection nozzle can be made inconspicuous.

  Therefore, according to the first embodiment, when the deviation of the landing position of the adjacent nozzle occurs in the direction away from the non-ejecting nozzle, the correction intensity is lower than that in the case where the deviation of the landing position of the adjacent nozzle does not occur. Can be suppressed from remaining as a white streak after correction, as compared with the configuration in which is calculated.

  Further, in the first embodiment, for example, even if the displacement of the landing positions of the adjacent nozzles on the + T side and the −T side of the non-discharge nozzle occurs in the direction approaching the non-discharge nozzle, the displacement of the landing position is taken into consideration. By reducing the density around the non-ejection nozzle, a shift in the landing position is dealt with. Thus, in the first embodiment, even if the landing position of the adjacent nozzle shifts in the direction approaching the non-ejection nozzle, the density around the non-ejection nozzle becomes unnecessarily high due to coalescence of the correction drops. Can be suppressed.

  Therefore, according to the first embodiment, when the deviation of the landing position of the adjacent nozzle occurs in the direction approaching the non-ejection nozzle, the correction value has a stronger correction intensity than when the deviation of the landing position of the adjacent nozzle does not occur. The occurrence of black streaks after the correction can be suppressed as compared with the configuration in which is calculated.

  In the first embodiment, the calculation unit 52 further calculates a correction value using an input pixel value of a pixel corresponding to an adjacent nozzle.

  Specifically, when the input pixel value of the pixel corresponding to the adjacent nozzle is “0 or more and 100 or less” or “200 or more and 255 or less”, the calculation unit 52 calculates the correction value regardless of the displacement of the landing position. It is calculated as “−5”. As described above, when the correction value is “−5”, the correction unit 53 determines the correction table used for the correction to be the correction table of “correction intensity: weak”. That is, when the input pixel value of the pixel corresponding to the adjacent nozzle is “0 or more and 100 or less” or “200 or more and 255 or less”, the calculation unit 52 uses the correction table of “correction intensity: weak” in the correction. The correction value is calculated so as to be adjusted.

  Thus, in the first embodiment, for example, the input pixel value of the pixel corresponding to the adjacent nozzle is low (eg, input pixel value “0 or more and 100 or less”) or high (example: input pixel value “200”). As described above, the density around the non-ejection nozzle can be prevented from becoming unnecessarily high. Therefore, according to the first embodiment, compared to a configuration in which the input pixel value of the pixel corresponding to the adjacent nozzle is not used in the calculation of the correction value, the correction intensity according to the input pixel value of the pixel corresponding to the adjacent nozzle is higher. Corrections can be made.

  In the first embodiment, the calculation unit 52 further calculates a correction value in consideration of landing interference. In the first embodiment, the calculation unit 52 calculates the correction value as the landing interference in consideration of the case where the ink droplet to be subsequently ejected becomes the correction droplet.

  Here, the post-strike ink droplet has a higher dynamic surface tension of the ink than the pre-strike ink droplet, and when the pre-strike ink droplet and the post-strike ink droplet unite, the post-strike ink droplet It is believed that the droplets are more likely to be drawn to the first ink droplet side.

  Then, the ink droplet of the later ejection is drawn to the ink droplet side of the earlier ejection, and when the ink droplet of the earlier ejection and the ink droplet of the later ejection unite, the ink droplet of the earlier ejection than the actually landed position The ink droplet to be ejected later is located to the side. That is, when the ink droplets of the first ejection and the ink droplets of the second ejection unite, the ink droplet of the second ejection as the correction droplet is separated from the pixel corresponding to the non-ejection nozzle.

  Therefore, the calculation unit 52 determines that the nozzle of the head unit 26 that discharges the ink droplet of the first ejection becomes the non-ejection nozzle, and the ink droplet of the second ejection ejected from the adjacent nozzle adjacent to the non-ejection nozzle becomes the correction droplet. In this case, the correction value is calculated so that the correction strength of the correction performed by the correction unit 53 is higher than the case where the ink droplet of the first ejection becomes the correction droplet for the ink droplet of the subsequent ejection. In this case, the calculation unit 52 calculates a correction value by adding “+3” to the displacement of the landing position of the adjacent nozzle that ejects the ink droplet to be ejected later. That is, the correction value in this case is represented by “(displacement of landing position of adjacent nozzle on + T side of non-discharge nozzle) − (displacement of landing position of adjacent nozzle on −T side of non-discharge nozzle) + (+ 3)”. Is calculated.

  As described above, when “+3” is added to the deviation of the landing position and the correction value used for the ink droplet to be ejected as a correction droplet is calculated, the correction is performed without adding “+3” to the deviation of the landing position. The correction unit 53 determines a correction table having a correction strength one step higher than that of the previously ejected ink droplet as a correction table used in the correction. In other words, the calculation unit 52 has a correction intensity that is one step stronger than the case where the ink droplet of the first ejection becomes the correction droplet when the ink droplet of the subsequent ejection becomes the correction droplet when the ink droplet of the subsequent ejection becomes the correction droplet. The correction value is calculated so that the correction table is used.

  With the above-described configuration, according to the first embodiment, even when landing interference occurs, it is generated by the non-ejection nozzle with higher accuracy than in a configuration in which landing correction is not considered in the calculation of the correction value. White streaks can be made inconspicuous.

  More specifically, in the first embodiment, the correction strength for the ink droplets to be ejected later is set to a high value in advance, and the density around the non-ejection nozzle is increased in consideration of the landing interference to deal with the landing interference. I have. Therefore, according to the first embodiment, when the ink droplet of the later ejection becomes the correction droplet, the correction intensity of the ink droplet of the subsequent ejection becomes smaller than that of the ink droplet of the previous ejection becomes the correction droplet. It is possible to make white streaks generated by non-ejection nozzles more inconspicuous than with a configuration in which a weak correction value is calculated.

  The correction unit 53 determines a correction table to be used in the correction using the correction values calculated by the calculation unit 52 from the five types of correction tables according to the strength of the correction intensity. Then, the correction unit 53 causes the head unit 26 to form an image using output pixel values corresponding to the input pixel values stored in the determined correction table.

  That is, in the first embodiment, it is not necessary to calculate the output pixel value each time an image is formed on the pixel corresponding to the adjacent nozzle, and the corrected output pixel value corresponding to the already stored input pixel value. A value may be selected, and the head unit 26 may form an image with the output pixel value. Therefore, according to the first embodiment, each time an image is formed on a pixel corresponding to an adjacent nozzle, the pixel value corresponding to the adjacent nozzle is easily compared with a configuration in which the pixel value of the pixel corresponding to the adjacent nozzle is calculated. An image can be formed.

(Second embodiment)
A second embodiment of the present embodiment will be described while omitting or simplifying an overlapping part with the first embodiment.
The image forming apparatus 10 according to the second embodiment forms an image on coated paper as an example of a non-permeable recording medium. The “non-permeable recording medium” refers to a recording medium in which the liquid permeates more slowly than a recording medium other than the non-permeable recording medium, such as plain paper. Note that examples of the non-permeable recording medium include, in addition to coated paper, films, plates, and the like made of resin, metal, glass, ceramics, silicon, rubber, and the like.

  The calculation unit 52 in the second embodiment calculates the correction value in consideration of the case where coated paper is used as the landing interference.

  Here, when ink droplets are ejected on coated paper, compared to when ink droplets are ejected on paper other than coated paper, the ink droplets are less likely to penetrate the paper. May remain high. In this case, the post-strike ink droplet is attracted to the pre-strike ink droplet remaining on the surface of the coated paper, and landing interference occurs in which the pre-strike ink droplet and the post-strike ink droplet unite. There is.

  In the case where the above-described landing interference occurs, similarly to the first embodiment, the position of the ink droplet to be ejected is shifted to the side of the ink droplet of the first ejection from the position of the actual impact, and the position of the ink droplet after the ink ejection becomes the correction droplet. The ejected ink droplet may be separated from the pixel corresponding to the non-ejection nozzle.

  Therefore, the calculation unit 52 calculates the correction value such that the correction intensity of the correction performed by the correction unit 53 is higher when using coated paper than when using paper other than coated paper.

  Specifically, the calculation unit 52 calculates a correction value by adding “+3” to the deviation of the landing position of the adjacent nozzle. Also in the second embodiment, similarly to the first embodiment, when the correction value is calculated by adding “+3” to the displacement of the landing position, the correction value is calculated before adding “+3” to the displacement of the landing position. Also, the correction unit 53 determines a correction table having a one-step higher correction strength as a correction table used in the correction. That is, the calculation unit 52 uses a correction table having a correction strength one step higher than that of the first embodiment using paper other than coated paper (continuous paper P) in the second embodiment using coated paper. The correction value is calculated.

  As described above, in the second embodiment, the correction intensity is set higher in advance than in the case of using paper other than the coated paper, and the density around the non-ejection nozzle is increased in consideration of landing interference. Dealing with landing interference.

  Therefore, according to the second embodiment, when coated paper is used, compared to a configuration in which a correction value having a lower correction strength is calculated than when using paper other than coated paper, coated paper is used. Even in this case, white streaks generated by the non-ejection nozzle can be made inconspicuous with high accuracy.

  The correction unit 53 according to the second embodiment determines a multiplication value to be used in the correction from a correction table in which a multiplication value corresponding to an input pixel value as correction information regarding correction performed by the correction unit 53 is stored.

  Specifically, as shown in FIG. 16, when the input pixel value is “0 or more and less than 100”, the correction unit 53 determines the multiplication value to be “1.2” and sets the input pixel value to “100 or more”. In the case of "less than 200", the multiplication value is determined to be "1.5", and in the case where the input pixel value is "200 or more and 255 or less", the multiplication value is determined to be "1.3".

  The correction unit 53 corrects the input pixel value of the pixel corresponding to the adjacent nozzle using the determined multiplication value and the correction value calculated by the calculation unit 52, and outputs the output pixel value corresponding to the input pixel value. Generate.

  Here, the calculation formula of the corrected output pixel value in the second embodiment is as follows.

  Output pixel value = input pixel value + basic value + correction value * multiplication value

  The basic value is a fixed value that is added to the input pixel value of the pixel corresponding to the adjacent nozzle regardless of the input pixel value, the correction value, and the multiplication value, and is stored in a predetermined storage area of the correction unit 53. ing. In the second embodiment, the basic value is set to “+10”.

  Note that, when a decimal portion is generated by performing the above calculation, the correction unit 53 performs rounding to one decimal place.

  For example, when the input pixel value is “100” and the correction value is “+5”, the correction unit 53 calculates the corrected output pixel value as “118” (100 + 10 + (+ 5 * 1.5). ) = 118). Note that the above-described correction value “+5” is calculated by the calculation unit 52 by adding “+3” in consideration of the coated paper to “+2”, which is the deviation of the landing position of the adjacent nozzle.

  As described above, the correction unit 53 in the second embodiment calculates the corrected output pixel value by the calculation using the input pixel value, the basic value, the correction value, and the multiplication value.

  The correction value in the second embodiment is not a threshold value for determining one corresponding correction table from among a plurality of correction tables, but a value directly used when calculating a corrected output pixel value. I can say.

  Therefore, according to the second embodiment, it is possible to accurately correct the pixel value of the pixel corresponding to the adjacent nozzle, as compared with a configuration in which correction is performed with a common correction intensity within a fixed correction value range. .

(Other)
In the above embodiment, the calculation unit 52 calculates the correction value for correcting the input pixel value of the pixel corresponding to the adjacent nozzle using the displacement of the landing position, and the correction unit 53 is calculated by the calculation unit 52. The input pixel value of the pixel corresponding to the adjacent nozzle on the + T side and the −T side of the non-ejection nozzle is corrected using the corrected value. For example, in the above embodiment, when the correction value is “−5”, the correction table of “correction intensity: weak” is used for both the adjacent nozzles on the + T side and the −T side of the non-ejection nozzle.

  However, the present invention is not limited to this. The calculating unit 52 calculates a correction value for each of the adjacent nozzles on the + T side and the −T side of the non-ejection nozzle, and the correcting unit 53 calculates each correction value calculated by the calculating unit 52. The correction may be used to correct the input pixel value of the pixel corresponding to each adjacent nozzle. In this case, when the displacement of the landing position of the adjacent nozzle occurs in the direction away from the non-discharge nozzle, the calculation unit 52 calculates the displacement of the landing position as a correction value as a positive number, and When the landing position of the adjacent nozzle shifts in the approaching direction, the landing position shift may be calculated as a negative value as a correction value.

  With the above configuration, the correction table having different correction strengths for the adjacent nozzles on the + T side and the −T side of the non-ejection nozzle is determined, and as the correction value increases, the correction table has a higher correction strength. And a correction table having a lower correction intensity as the negative value of the correction value increases.

  In the above embodiment, the correction unit 53 uses the original data table and the adjustment value table to generate output pixel values corresponding to input pixel values stored in each correction table. However, a configuration may be adopted in which the original data table and the adjustment value table are not provided, and only the correction table in which the output pixel value of the pixel corresponding to the adjacent nozzle in which the landing position shift is considered in advance is stored.

10 Image Forming Apparatus 26 Head Unit (Example of Image Forming Unit)
52 calculation unit 53 correction unit

Claims (12)

When forming an image on a recording medium, basic information indicating a predetermined landing position of a droplet ejected from an adjacent nozzle adjacent to a non-ejection nozzle where no droplet is ejected, and the droplet ejected from the adjacent nozzle From the position information of the landing positions of the droplets, calculate the deviation of the landing positions of the adjacent nozzles, and use the deviation of the landing positions to calculate a correction value for correcting the pixel value of the pixel corresponding to the adjacent nozzle. A calculating unit for calculating,
A correction unit that corrects a pixel value of a pixel corresponding to the adjacent nozzle using the correction value calculated by the calculation unit;
An image processing apparatus comprising:   The calculation unit may be configured such that, when the landing position shifts in a direction intersecting with the transport direction of the recording medium, the correction intensity of the correction performed by the correction unit changes in accordance with the direction of the cross direction. The image processing apparatus according to claim 1, wherein the value is calculated.   The calculation unit increases the correction strength when the direction of the cross direction is a direction away from the non-discharge nozzle, as compared with the case where the direction of the cross direction is a direction approaching the non-discharge nozzle. The image processing apparatus according to claim 2, wherein the correction value is calculated in such a manner.   The calculation unit may be configured such that, when the direction of the cross direction is a direction approaching the non-discharge nozzle, the correction strength is weaker than when the direction of the cross direction is a direction away from the non-discharge nozzle. 4. The image processing apparatus according to claim 2, wherein the correction value is calculated.   The image processing device according to claim 1, wherein the calculation unit further calculates the correction value using a pixel value of a pixel corresponding to the adjacent nozzle.   The correction unit, from a plurality of correspondence tables in which correction information regarding the correction performed by the correction unit is stored, using the correction value calculated by the calculation unit, determine the correspondence table used in the correction, The image processing apparatus according to claim 1, wherein the correction information of the determined correspondence table is used.   The correction unit determines the correction information to be used in the correction from a correspondence table in which correction information regarding correction performed by the correction unit is stored, and determines the determined correction information and the correction calculated by the calculation unit. The image processing apparatus according to claim 1, wherein a pixel value of a pixel corresponding to the adjacent nozzle is corrected using a value.   The image processing apparatus according to claim 1, wherein the calculation unit calculates the correction value in consideration of landing interference.   The calculation unit is configured such that when the non-permeable recording medium is used, the correction strength of the correction performed by the correction unit is smaller than when the non-permeable recording medium other than the recording medium is used. The image processing apparatus according to claim 8, wherein the correction value is calculated to be stronger.   The calculating unit is configured to determine, for the second droplet that is adjacent to the first droplet and lands on the recording medium after the first droplet, by the correction unit compared to the first droplet. The image processing apparatus according to claim 8, wherein the correction value is calculated such that a correction strength of the correction performed is increased.   An image processing program for causing a computer to function as a calculation unit and a correction unit of the image processing apparatus according to any one of claims 1 to 10. An image processing apparatus according to any one of claims 1 to 10,
An image forming unit that forms an image on which image processing has been performed by the image processing apparatus on the recording medium;
An image forming apparatus comprising: