Image forming apparatus, image forming system, image forming method, and program

Abstract

The present invention provides an image forming apparatus, an image forming system, an image forming method, and a program that can efficiently perform color measurement of required color patches. [Solution] The image forming apparatus 1 comprises an image forming unit 5 that forms an image on a recording medium 100, a reading unit 6 that reads the image formed on the recording medium 100, a colorimetric unit 9 that measures the color of the image formed on the recording medium 100, and a control unit 2. The control unit 2 comprises an inspection unit 22 that checks whether each of the multiple color patches 111 has an abnormality based on the image data of the multiple color patches 111 acquired from the reading unit 6, a determination unit 23 that determines whether the color patch 111 can be measured by the colorimetric unit 9 based on the inspection results of the inspection unit 22, and an instruction unit 24 that causes the image forming unit 5 to reform only the color patches 111 that the determination unit 23 has determined cannot be measured by the colorimetric unit 9.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, an image forming system, an image forming method, and a program.

Background Art

[0002] Conventionally, in an image forming apparatus including an image forming unit, in order to form an image with high color reproducibility, a color patch is formed on a recording medium, the color patch is read by a predetermined reading device, and a colorimetric process for calculating a correction value of an image formed by the image forming unit is performed.

[0003] In this control, if there are image defects such as dirt or streaks in the formed color patch, an error occurs in the reading result by the reading device. Therefore, in Patent Document 1, a plurality of color patches are formed in the conveyance direction of the recording medium, and as a result of reading by a first image detection unit upstream in the conveyance direction, a color patch determined to have no image defect is read by a second image detection unit downstream in the conveyance direction. An image forming apparatus is described. According to this configuration, for example, even if some of the plurality of color patches read by the first image detection unit among the plurality of formed color patches have image defects, a normal color patch is read by the second image detection unit, and thus a correction value of the image can be calculated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the image forming apparatus of Patent Document 1 does not describe the recovery of the color patch in which a defect is found, there is a case where the colorimetry of the necessary color patch cannot be efficiently executed.

[0006] This invention has been made in view of the above circumstances. Its purpose is to provide an image forming apparatus, an image forming system, an image forming method, and a program that can efficiently perform color measurement of required color patches. [Means for solving the problem]

[0007] To solve the above problems, the invention described in claim 1 is an image forming apparatus, The system comprises an image forming unit that forms an image on a recording medium, a reading unit that reads the image formed on the recording medium, a colorimetric unit that measures the color of the image formed on the recording medium, and a control unit. The control unit includes an inspection unit that checks whether each of the multiple color patches has an abnormality based on the image data of the multiple color patches acquired from the reading unit, A determination unit determines whether or not a color patch is capable of being measured by the color measurement unit, based on the inspection results of the inspection unit. The determination unit is instructed to cause the image forming unit to reshape only the color patches that the color measuring unit has determined cannot measure, It is equipped with.

[0008] The invention described in claim 2 is an image forming apparatus according to claim 1, The control unit includes a calculation unit that calculates the number of color patches that can be formed on the recording medium. The calculation unit obtains the length of the recording medium in the transport direction and the length in the width direction perpendicular to the transport direction, and the length of the color chart composed of the plurality of color patches in the transport direction and the length in the width direction, and calculates that it is possible to form a plurality of color charts if the length of the color chart in the transport direction is half or less of the length of the recording medium in the transport direction, or if the length of the color chart in the width direction is half or less of the length of the recording medium in the width direction.

[0009] The invention described in claim 3 is an image forming apparatus according to claim 2, If the calculation unit calculates that multiple color charts can be formed in the transport direction of the recording medium, the control unit causes the arrangement of the corresponding color patches among the multiple color charts to differ in the width direction.

[0010] The invention described in claim 4 is an image forming apparatus according to claim 2, If the inspection unit determines that a first color patch of a first color chart, which is composed of multiple color patches, has an abnormality, it then inspects whether a second color patch of the same type as the first color patch in a second color chart, which is different from the first color chart, has an abnormality.

[0011] The invention described in claim 5 is an image forming apparatus according to claim 4, If the inspection unit determines that the first color patch and the second color patch have an abnormality, and the determination unit determines that the first color patch and the second color patch are not color patches that can be measured by the colorimeter, the instruction unit instructs the image forming unit to reform the color patches in the empty area on the first surface of the recording medium on which the first color patch and the second color patch are formed.

[0012] The invention described in claim 6 is an image forming apparatus according to claim 4, A reversal mechanism is provided downstream of the image forming section in the transport direction, which reverses the surface on which the image is formed on the recording medium and passes it through the image forming section again. If the inspection unit determines that the first color patch and the second color patch have an abnormality, and the determination unit determines that the first color patch and the second color patch are not color patches that can be measured by the colorimeter, the instruction unit instructs the image forming unit to reform the color patches on the second surface of the recording medium opposite to the first surface on which the first color patch and the second color patch are formed.

[0013] The invention described in claim 7 is an image forming apparatus according to claim 4, When the inspection unit determines that the first color patch and the second color patch have abnormalities, and the determination unit determines that the first color patch and the second color patch are not color patches that can be color-measured by the color measurement unit, the instruction unit instructs the image forming unit to reform the color patch on a recording medium different from the recording medium on which the first color patch and the second color patch are formed.

[0014] The invention according to claim 8 is an image forming apparatus according to any one of claims 5 to 7, The image forming unit includes a plurality of inkjet heads, The instruction unit causes the second inkjet head different from the first inkjet head that formed the color patch to reform the color patch.

[0015] The invention according to claim 9 is an image forming apparatus according to any one of claims 5 to 7, Based on the calculation result of the calculation unit, the instruction unit instructs the image forming unit to reform a plurality of color patches.

[0016] The invention according to claim 10 is an image forming apparatus according to any one of claims 1 to 7, The reading unit is an in-line sensor provided downstream of the image forming unit in the conveyance direction.

[0017] The invention according to claim 11 is an image forming apparatus according to any one of claims 1 to 7, The inspection unit compares the image data with correct image data and detects the presence or absence of dirt, chips, or streaks in the image data.

[0018] The invention according to claim 12 is An image forming system including an image forming apparatus having an image forming unit that forms an image on a recording medium, a reading unit that reads an image formed on the recording medium, and a color measurement unit that measures the color of the image formed on the recording medium, an inspection unit that inspects whether each of the plurality of color patches has an abnormality based on the image data of the plurality of color patches acquired from the reading unit, a determination unit that determines whether a color patch is a color patch that can be color-measured by the color measurement unit based on the inspection result of the inspection unit, an instruction unit that instructs the image forming unit to reform only the color patch determined by the determination unit that cannot be color-measured by the color measurement unit, and comprising.

[0019] The invention according to claim 13 is an image forming method by an image forming apparatus including an image forming unit that forms an image on a recording medium, a reading unit that reads an image formed on the recording medium, a color measurement unit that measures the color of the image formed on the recording medium, and a control unit, wherein the control unit includes an inspection step of inspecting whether each of the plurality of color patches has an abnormality based on the image data of the plurality of color patches acquired from the reading unit, a determination step of determining whether a color patch is a color patch that can be color-measured by the color measurement unit based on the inspection result of the inspection step, and an instruction step of instructing the image forming unit to reform only the color patch determined in the determination step that cannot be color-measured by the color measurement unit.

[0020] The invention according to claim 14 is a program, causing a computer of an image forming apparatus including an image forming unit that forms an image on a recording medium, a reading unit that reads an image formed on the recording medium, and a color measurement unit that measures the color of the image formed on the recording medium, to be an inspection unit that inspects whether each of the plurality of color patches has an abnormality based on the image data of the plurality of color patches acquired from the reading unit, A determination unit determines whether or not a color patch is capable of being measured by the color measurement unit, based on the inspection results of the inspection unit. The determination unit is configured to function as an instruction unit that causes the image forming unit to reshape only the color patches that the color measurement unit has determined cannot measure. [Effects of the Invention]

[0021] According to the present invention, the colorimetric measurement of the required color patches can be performed efficiently. [Brief explanation of the drawing]

[0022] [Figure 1] This is a side cross-sectional view of an image forming apparatus. [Figure 2] This is a block diagram of an image forming apparatus. [Figure 3] This is a top view showing an example of a recording medium in which multiple color charts are formed in the transport direction. [Figure 4] This is a top view showing an example of a recording medium in which multiple color charts are formed in the width direction. [Figure 5] This is a top view showing another example of a recording medium in which multiple color charts are formed in the transport direction. [Figure 6] This is a flowchart showing the flow of the color measurement process. [Modes for carrying out the invention]

[0023] The following description illustrates one or more embodiments of the present invention with reference to the drawings. The effects and features of the embodiments of the present invention will be understood from the following detailed description and drawings. The following detailed description and drawings are provided for illustrative purposes only and do not limit the scope of the present invention.

[0024] In the following, the X, Y, and Z directions refer to the directions shown in Figure 1. Furthermore, in the following explanation, the X, Y, and Z directions will also be referred to as the width direction, conveying direction, and height direction, respectively.

[0025] [Overall configuration of the image forming apparatus] Figure 1 is a schematic diagram of the image forming apparatus 1 according to this embodiment. Figure 2 is a block diagram showing the functional configuration of the image forming apparatus 1 according to this embodiment. In the following description, the image forming apparatus 1 is assumed to be an inkjet recording apparatus in which the image forming unit 5, described later, is equipped with multiple inkjet heads and forms an image on the recording medium 100 using an inkjet recording method.

[0026] The image forming apparatus 1 includes an image forming unit 5. As shown in Figure 1, the image forming apparatus 1 includes a control unit 2, a paper feeding unit 3, a transport unit 4, a reading unit 6, a first discharge unit 8, a colorimetric unit 9, and a second discharge unit 12. In addition, as shown in Figure 2, the image forming apparatus 1 may also include a cleaning unit 7, a measuring unit 10, a notification unit 11, a storage unit 13, and a bus 14.

[0027] (Recording medium) Various media capable of fixing ink deposited on the surface can be used as the recording medium 100. Examples of the recording medium 100 include paper, fabric, and sheet-like resin. When the recording medium 100 is paper, examples include plain paper and coated paper. In particular, sheet paper is preferred for the recording medium 100.

[0028] (Paper feed section) The paper feeding unit 3 includes, for example, a tray for storing the transported recording media 100, and stores the recording media 100 in the tray. As mentioned above, multiple types of media can be used as the recording media 100. Therefore, although Figure 1 illustrates a case where the paper feeding unit 3 has only one tray, it may also have multiple trays, each for storing multiple types of recording media 100, and use any recording media 100 according to instructions.

[0029] (Transportation section) The transport unit 4 transports the recording medium 100 in the transport direction. As shown in Figure 1, the transport unit 4 includes, for example, a feeder board 41, a first transfer drum 42, a transport drum 43, a second transfer drum 44, and an unloading unit 45.

[0030] {Feeder board, first handover drum} The feeder board 41 transports the recording medium 100 from the paper feeding unit 3 to the first transfer drum 42. The first transfer drum 42 holds one end of the recording medium 100 transported by the feeder board 41, picks it up, and transfers it to the transport drum 43.

[0031] {transport drum} The transport drum 43 is cylindrical in shape. The side surface of the transport drum 43 serves as a transport surface that attracts and holds the recording medium 100. With the recording medium 100 held on the transport surface, the transport drum 43 rotates in the transport direction around its central axis, which extends in the width direction, as the axis of rotation. As a result, the transport drum 43 transports the recording medium 100, which is attracted and held on the transport surface, along the transport surface.

[0032] Furthermore, the transport drum 43 is equipped with a reversal mechanism 43a downstream of the reading unit 6 in the transport direction. The reversal mechanism 43a reverses the front and back sides of the printed material 200 and transports it again in the transport direction by the transport drum 43, so that the back side (second side) opposite to the front side (first side) of the printed material 200 passes through the image forming unit 5. By equipping the transport unit 4 with such a reversal mechanism 43a, images can be formed not only on the front side but also on the back side of the printed material 200.

[0033] {Second handover drum} The second transfer drum 44 holds one end of the printed material 200 that has been transported by the transport drum 43, picks it up, and hands it over to the discharge unit 45.

[0034] {Loading section} The discharge section 45 is the discharge path for the printed material 200, and discharges the printed material 200 to discharge sections such as the first discharge section 8 and the second discharge section 12. The discharge section 45 is composed of, for example, a belt or rollers. If there are multiple discharge sections, for example, if the image forming apparatus 1 has a second discharge section 12 in addition to the first discharge section 8, the discharge path in the discharge section 45 may branch along the way as shown in Figure 1.

[0035] (Image forming unit) The image forming unit 5 forms an image on the recording medium 100 based on the image data acquired from the control unit 2. The image forming unit 5 is equipped with one or more head units 51 arranged in the width direction, each having a length (width) that covers the entire recording medium 100. In other words, the image forming unit 5 produces the printed material 200 using a one-pass method (single-pass method, line head method).

[0036] {Head Unit} Each head unit 51 is equipped with one or more inkjet heads. The head unit 51 is equipped with an ink ejection surface located opposite the transport surface of the transport drum 43. The head unit 51 ejects ink onto the recording medium 100 held on the transport drum 43 at an appropriate timing corresponding to the rotation of the transport drum 43 to form an image and produce a printed material 200.

[0037] In the image forming apparatus 1 illustrated in Figure 1, four head units 51 are arranged at predetermined intervals from upstream in the rotational direction of the transport drum 43. The four head units 51 each eject four inks, for example, yellow (Y), magenta (M), cyan (C), and black (K).

[0038] The image forming unit 5 performs normal jobs, color measurement jobs, etc. A normal job is a printing job that forms a normal image on the recording medium 100 that is not subject to color measurement. A color measurement job is a printing job that forms a color chart 110 (see Figure 3) that is subject to color measurement on the recording medium 100.

[0039] The color chart 110 is an image used by the image forming unit 5 to detect color misalignment. The color chart 110 is composed of multiple color patches 111 (see Figure 3) with different gradation values, such as primary colors (C, M, Y, and K) and secondary colors (mixtures of primary colors).

[0040] (Reading section) The reading unit 6 irradiates the printed material 200 with light from a light source and reads the reflected image. The reading unit 6 is composed of an inline sensor in which multiple detection elements are arranged along the width direction of the recording medium 100 within the image forming apparatus 1. The read image data, which is the image data read by the reading unit 6, is sent to the inspection unit 22 of the control unit 2 (described later) for inspection processing.

[0041] (Cleaning Department) The cleaning unit 7 performs maintenance by cleaning the head unit 51. For example, the cleaning unit 7 is installed adjacent to the transport drum 43 on the width side of the transport drum 43. The cleaning unit 7 then cleans the head unit 51 as it moves in the width direction. Examples of cleaning include wiping to remove ink adhering to the ink ejection surface and purging to eject ink from the ink flow path.

[0042] (1st discharge section) The printed material 200 is discharged into the first discharge unit 8. The first discharge unit 8 includes, for example, a tray for storing the printed material 200 and a colorimeter 9.

[0043] (Color measurement department) The colorimeter 9 is, for example, an inline colorimeter located above the first discharge unit 8. The colorimeter 9 performs the colorimetering process. Specifically, the colorimeter 9 performs color measurement on the printed material 200, which is in a stopped state in the first discharge unit 8, based on control by the control unit 2. Colorimetering is the measurement of color information, for example, L * a * b * This involves measuring color values ​​such as numerical values. For example, a spectrophotometer that spectrally analyzes reflected light from a printed material 200 to measure its color can be used as the colorimeter 9.

[0044] In conventional printing equipment where the colorimeter is installed on the transport path of the printed material, subsequent printing jobs and maintenance work could not be performed while waiting for the color values ​​to stabilize for color measurement, resulting in low printing efficiency. In contrast, in this image forming apparatus 1, color measurement is performed by the colorimeter 9 in the first discharge unit 8. This configuration makes it easier to perform subsequent printing jobs and maintenance work while waiting for and / or during color measurement, enabling both color measurement and efficient printing.

[0045] Furthermore, because the colorimeter is a colorimeter unit 9 built into the image forming apparatus 1, rather than a colorimeter installed outside the image forming apparatus 1, it becomes easier to control the printing process and the colorimeter process.

[0046] Furthermore, performing color measurement on a stationary printed object 200 results in higher accuracy compared to performing color measurement on a moving printed object 200.

[0047] Furthermore, the "color measurement of a stationary printed material 200" according to the present invention also includes color measurement by repeatedly measuring the color of a part of the stationary printed material 200 and moving the printed material 200.

[0048] For example, first, the colorimeter 9 scans the printed material 200 in the width direction and measures the color of the first row of the stationary printed material 200 in the transport direction. The row of the printed material 200 at this time is, for example, the range that the colorimeter 9 can measure in a single scan. Once the color measurement of the first row of the printed material 200 is complete, the printed material 200 moves one row within the first discharge unit 8. Next, the colorimeter 9 scans the printed material 200 again in the width direction and measures the color of the second row adjacent to the first row of the stationary printed material 200 in the transport direction. Once the color measurement of the second row of the printed material 200 in the transport direction is complete, the printed material 200 moves one row again within the first discharge unit 8.

[0049] Thus, the color measurement according to the present invention does not need to be performed in a single step on the stationary printed material 200, but may be performed while the printed material 200 is repeatedly stopped and moved.

[0050] The color values ​​of the printed material 200 discharged to the first discharge unit 8 may not stabilize immediately due to reasons such as the ink not yet being dry. Therefore, the color measurement process may be performed after a predetermined color measurement waiting time has elapsed following the discharge of the printed material 200 to the first discharge unit 8.

[0051] The color measurement waiting time may be adjusted according to at least one of the following: paper type, paper thickness, ink type, image density, and ink amount of the printed material 200. The ink amount may be the total ink amount of the printed material 200, or the maximum ink amount per unit area of ​​the printed material 200. The color measurement waiting time may be adjusted according to at least one of the following: the paper surface temperature of the printed material 200 at the time of printing, the temperature of the first discharge unit 8, and the humidity of the first discharge unit 8. The adjustment of the color measurement waiting time may be performed by the user or based on control by the control unit 2.

[0052] (Measurement part) The measuring unit 10 is located near the first discharge unit 8 and measures the temperature and / or humidity of the first discharge unit 8. The temperature and / or humidity of the first discharge unit 8 measured by the measuring unit 10 are used, for example, to adjust the color measurement waiting time.

[0053] (Notification Department) The notification unit 11 notifies the system of the color measurement information obtained by the color measurement unit 9, for example, by displaying it on a screen. The color measurement information notified by the notification unit 11 is, for example, information such as whether or not the variation in the color values ​​of the printed material 200 exceeds an acceptable value.

[0054] (2nd discharge section) The printed material 200 is discharged into the second discharge unit 12. The second discharge unit 12 is a discharge unit provided separately from the first discharge unit 8. The second discharge unit 12 includes, for example, a tray for storing the printed material 200. If the image forming apparatus 1 is further equipped with a second discharge unit 12 in addition to the first discharge unit 8, for example, only printed material 200 that is subject to color measurement is discharged into the first discharge unit 8, and ordinary printed material 200 that is not subject to color measurement is discharged into the second discharge unit 12.

[0055] (Control Unit) The control unit 2 controls the operation of other functional components according to the print image data, print settings, etc. The control unit 2 is a computer and includes, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory). The CPU executes various control programs to drive and control the image forming apparatus 1 and performs various calculations. The RAM provides the CPU with working memory space and stores temporary data.

[0056] RAM may include non-volatile memory. ROM stores various control programs executed by the CPU, configuration data, etc. Instead of ROM, rewritable non-volatile memory such as flash memory may be used.

[0057] The control unit 2 functions as a calculation unit 21, inspection unit 22, determination unit 23, instruction unit 24, selection unit 25, and correction unit 26 when the CPU executes a program.

[0058] {Calculation Unit} In the color measurement process described later, the calculation unit 21 obtains, for example, the length of the recording medium 100 configured to form color patches 111, and the length of one color patch 111 from the storage unit 13. Based on this acquired data, the calculation unit 21 calculates the number of color patches 111 that can be formed on the recording medium 100. Based on the calculated number of color patches 111 that can be formed on the recording medium 100, the calculation unit 21 calculates the number of color charts 110 that can be formed on the recording medium 100.

[0059] For example, as shown in Figure 3, the ratio of the length 100L of the recording medium 100 in the transport direction to the length 110L of one color chart 110 to be formed is set to a predetermined integer value (2) or more. In this case, the calculation unit 21 calculates that it is possible to form that integer number (2) color charts 110 in the transport direction of the recording medium 100.

[0060] Furthermore, as shown in Figure 4, for example, the ratio of the widthwise length 100W of the recording medium 100 to the widthwise length 110W of one color chart 110 to be formed is a predetermined integer value (2) or more. In this case, the calculation unit 21 calculates that it is possible to form that integer value number (2) of color charts 110 in the widthwise direction of the recording medium 100.

[0061] Thus, the calculation unit 21 determines whether the ratio of the length 100L of the recording medium 100 in the transport direction to the length 110L of one color chart 110 in the transport direction is an integer value n or greater. The calculation unit 21 also determines whether the ratio of the length 100W of the recording medium 100 in the width direction to the length 110W of one color chart 110 in the width direction is an integer value n or greater. Then, the calculation unit 21 calculates that if the ratio of the length of the recording medium 100 to the length of one color chart 110 is n or greater (where n is a positive integer), it is possible to form n color charts 110 in the corresponding direction of the recording medium 100.

[0062] Although Figures 3 and 4 illustrate the case where two color charts are formed, it is of course possible to form three or more color charts 110 if the ratio of the length of the recording medium 100 to the length of the color chart 110 is 3 or more. On the other hand, if too many color charts 110 are formed, they will not be measured in the color measurement process, and the amount of ink consumed will only increase unnecessarily. Therefore, in case the ratio of the length of the recording medium 100 to the length of one color chart 110 is large, it is preferable to set a predetermined upper limit on the number of color charts 110 formed on the recording medium 100.

[0063] Furthermore, especially when multiple color charts 110 are formed in the transport direction, it is preferable that the arrangement of corresponding identical color patches 111 differs in the width direction in both color charts 110, as shown in Figure 5.

[0064] For example, if ink becomes clogged in the nozzle of the inkjet head and cannot be ejected, so-called white streaks will appear along the transport direction, as shown in the color patch 111 on the left in Figure 5. When white streaks appear, color measurement by the colorimeter 9 becomes impossible. Therefore, for example, as shown in Figure 3, if white streaks appear when the arrangement of color patches 111 in the width direction is exactly the same among multiple color charts 110 provided in the transport direction, it becomes necessary to reshape all the color patches 111 in the width direction where the white streaks occurred.

[0065] On the other hand, if a color chart 110 is formed as shown in Figure 5, even if a predetermined color patch 111 cannot be measured using the first color chart 110, a color patch 111 of the same type as the predetermined color patch 111 can be measured using the second color chart 110. Therefore, the effort of reshaping the color patch 111 is eliminated, which is preferable as it suppresses increased ink consumption and downtime.

[0066] {Inspection Department} The inspection unit 22 checks for any abnormalities on the recording medium 100, such as dirt, image defects, or white streaks, by comparing the read image data obtained by the reading unit 6 when it reads the color chart 110 with the correct image data. The correct image data is the image data of the color chart 110 stored in the storage unit 13.

[0067] {Judgment part} The determination unit 23 determines, based on the inspection results from the inspection unit 22, whether the color chart 110 formed on the recording medium 100 can be subjected to a color measurement process by the color measurement unit 9. For example, even if the inspection unit 22 detects an abnormality in the recording medium 100 or the color chart 110, the determination unit 23 determines that the color measurement process can be performed by the color measurement unit 9 if the abnormality is minor.

[0068] {instruction section} Based on the inspection results from the inspection unit 22 and the determination results from the determination unit 23, the instruction unit 24 instructs the image forming unit 5 to reform only the color patches 111 that the determination unit 23 has determined to be abnormal and therefore cannot be measured by the color measurement unit 9 onto the recording medium 100.

[0069] When reforming the color patch 111, the preferred locations for reformation are, in order: an empty area on the same recording medium 100, the back surface of the same recording medium 100, and then a newly transported other recording medium 100. This is because using another recording medium 100 increases the consumption of recording medium 100. Furthermore, inverting the recording medium 100 using the inversion mechanism 43a to reform the color patch 111 on the back surface of the recording medium 100 increases the downtime required for the color measurement process.

[0070] Furthermore, when reforming the color patch 111, considering the possibility that the inkjet head may be faulty, it is preferable to reform it using a different inkjet head than the one that formed the faulty color patch 111. Moreover, considering the possibility that the reformed color patch 111 may also be faulty, it is preferable to form multiple color patches 111 when reforming the color patch 111.

[0071] {Selection section} Based on the determination results of the inspection unit 22 and the determination unit 23, the selection unit 25 selects which of the color patches 111 formed on the recording medium 100 will be used as the color measurement target for the color measurement unit 9, and transmits the selection to the color measurement unit 9.

[0072] {correction section} The correction unit 26 calculates a correction value for the image formed by the image forming unit 5 based on the color measurement results of the color measurement unit 9, and performs color correction.

[0073] (Storage part) The memory unit 13 stores programs executed by the CPU, various configuration data, etc. For example, an HDD (Hard Disk Drive) may be used as the memory unit 13, and DRAM (Dynamic Random Access Memory) may be used in combination.

[0074] (bus) Bus 14 is a path for sending and receiving signals between the control unit 2 and other functional configurations. Each functional configuration may operate based on control signals sent from the control unit 2 and a separate processor.

[0075] [Color measurement process] The color measurement process using this image forming apparatus 1 will be explained based on the flowchart in Figure 6. The color measurement process may be performed at a predetermined time (for example, when a predetermined amount of time has elapsed since the previous color measurement process, or when a predetermined number of image forming processes have been performed since the previous color measurement process), or when an execution instruction is received from the user.

[0076] First, the control unit 2 of the image forming apparatus 1 determines the color chart 110 to be formed (step S101). For example, if the color gamut of the image to be formed in the printing process after the color measurement process has already been determined, the control unit 2 decides to form a color chart 110 composed of color patches 111 corresponding to the color gamut of that image. On the other hand, if the image to be formed after the color measurement process and its color gamut have not been determined, the control unit 2 decides to form a color chart 110 composed of color patches 111 corresponding to the entire color gamut that the image forming unit 5 can form.

[0077] Furthermore, the control unit 2 determines the recording medium 100 that will form the color chart 110 (step S102). Typically, the color measurement process uses the same type of recording medium 100 as the one used in the printing process, so the control unit 2 determines the recording medium 100 that will form the color chart 110 based on the user's instructions.

[0078] Alternatively, a user may form a color chart 110 on multiple types of recording media 100, and then, after checking how the colors are reproduced, decide which recording media 100 to use for the printing process. In this case, the multiple types of recording media 100 are selected to be the recording media 100 on which the color chart 110 is formed.

[0079] The calculation unit 21 obtains the color chart 110 determined in step S101 and the length of the recording medium 100 determined in step S102 from, for example, the storage unit 13, and determines the number of color charts 110 to be formed on the recording medium 100 based on this data (step S103). The length of the recording medium 100 may also be obtained from the measurement results of a known sensor provided in the paper feeding unit 3 or in the transport unit 4 upstream of the image forming unit 5 in the transport direction.

[0080] The control unit 2 causes the image forming unit 5 to form the number of color charts 110 determined in step S103 (step S104). After the color charts 110 are formed, the control unit 2 performs an inspection process. The reading unit 6 reads the first color charts 110 formed on the recording medium 100 and acquires read image data. The inspection unit 22 compares the read image data of the first color charts 110 acquired from the reading unit 6 with the correct image data stored in the storage unit 13 (step S105). The determination unit 23 then determines whether or not the color measurement process by the colorimeter 9 can be performed on all the color patches 111 of the first color chart 110 (step S106).

[0081] If the determination unit 23 determines that the color measurement process can be performed by the color measurement unit 9 for all color patches 111 (step S106; Yes), the control unit 2 transports the recording medium 100 to the first discharge unit 8 and causes the color measurement unit 9 to measure the color patches 111 (step S107). The correction unit 26 corrects the image forming unit 5 by calculating a correction value based on the color measurement result and ends the color measurement process.

[0082] If the determination unit 23 determines that the color measurement process by the colorimetric unit 9 cannot be performed for all color patches 111 (step S106; No), the control unit 2 determines whether or not there is a second color chart 110 on the recording medium 100 that has not been compared with the correct image data (step S108).

[0083] If a second color chart 110 that has not been compared with the correct image data exists on the recording medium 100 (step S108; Yes), the control unit 2 reads the second color chart 110 with the reading unit 6. The inspection unit 22 then inspects for abnormalities in the second color patch 111 of the second color chart 110 that corresponds to the first color patch 111 that the color measurement unit 9 determined could not perform the color measurement process on. The determination unit 23 then determines, based on the inspection result of the inspection unit 22, whether the second color patch 111 can perform the color measurement process on the color measurement unit 9 (step S109).

[0084] If the determination unit 23 determines that the corresponding second color patch 111 cannot also be measured by the colorimeter 9 (step S109; No), the control unit 2 proceeds to step S108 to determine whether there are other second color charts 110. On the other hand, if the determination unit 23 determines that the colorimeter 9 can perform the colorimeter process (step S109; Yes), the selection unit 25 selects the color patch 111 that the determination unit 23 determined to be measurable from among the color patches 111 of the first color chart 110 and the second color chart 110, and transmits it to the colorimeter 9. Then, the control unit 2 proceeds to step S107 to perform color measurement by the colorimeter 9.

[0085] If there is a color patch 111 that cannot be measured by the colorimetric unit 9, and there is no second color chart 110 that has not been compared with the correct image data (step S108; No), the instruction unit 24 instructs the transport unit 4 and the image forming unit 5 to reshape the color patch 111. Specifically, the control unit 2 first determines whether it is possible to reshape the color patch 111 that was determined in the previous step to be unable to be measured by the colorimetric unit 9 in an empty area of ​​the same recording medium 100 upstream of the image forming unit 5 in the transport direction (step S110).

[0086] If it is determined that the color patch 111 can be reformed in the empty area upstream of the recording medium 100 in the transport direction (step S110; Yes), the control unit 2 reforms the color patch 111 in the empty area (step S111) and proceeds to step S105. If it is not possible to reform the color patch 111 in the empty area upstream of the recording medium 100 in the transport direction (step S110; No), the control unit 2 determines whether or not the color patch 111 can be reformed on the back surface of the same recording medium 100 (step S112). The control unit 2 determines whether or not the color patch 111 can be reformed on the back surface of the same recording medium 100 according to at least one of the following: paper type, paper thickness, ink type, image density, and ink amount. If it is determined that the color patch 111 can be reformed on the back surface of the same recording medium 100 (step S112; Yes), the control unit 2 advances the transport of the recording medium 100, inverts it using the inversion mechanism 43a, and proceeds to steps S111 and S105.

[0087] If it is determined that the color patch 111 cannot be reformed on the back surface of the recording medium 100 (step S112; No), the control unit 2 transports another recording medium 100 of the same type from the paper feed unit 3 (step S113) and proceeds to steps S111 and S105.

[0088] [Effects of the Embodiment] As described above, the control unit 2 of the image forming apparatus 1 according to this embodiment includes an inspection unit 22 that checks whether each of the multiple color patches 111 has an abnormality based on the image data of the multiple color patches 111 acquired from the reading unit 6. The control unit 2 also includes a determination unit 23 that determines whether or not a color patch 111 can be measured by the colorimeter 9 based on the inspection results of the inspection unit 22. The control unit 2 also includes an instruction unit 24 that instructs the image forming unit 5 to reshape only the color patches 111 that the determination unit 23 has determined cannot be measured by the colorimeter 9. With this configuration, even if all the corresponding color patches 111 have abnormalities and are of insufficient quality, the instruction unit 24 reshapes only the color patches 111, so the color measurement of the required color patches can be performed efficiently.

[0089] Furthermore, the control unit 2 includes a calculation unit 21 that calculates the number of color patches 111 that can be formed on the recording medium 100. The calculation unit 21 obtains the lengths of the recording medium 100 in the transport direction and width direction, and the lengths of the color chart 110 in the transport direction and width direction. Then, if the length 110L of the color chart 110 in the transport direction is half or less of the length 100L of the recording medium 100 in the transport direction, it calculates that it is possible to form multiple color charts 110. Also, if the length 110W of the color chart 110 in the width direction is half or less of the length 100W of the recording medium 100 in the width direction, it calculates that it is possible to form multiple color charts 110. With this configuration, since multiple color charts 110 are formed on a single recording medium 100 according to the sizes of the recording medium 100 and the color chart 110, the possibility of completing the color measurement process without reforming the color patches 111 is increased, and the efficiency of the color measurement process is improved.

[0090] Furthermore, if the calculation unit 21 calculates that multiple color charts 110 can be formed in the transport direction of the recording medium 100, the control unit 2 arranges the corresponding color patches 111 in the width direction differently among the multiple color charts 110. With this configuration, even if an abnormality such as a white streak extending in the transport direction occurs in the color patch 111, the possibility of completing the color measurement process without reforming the color patch 111 is increased, thereby improving the efficiency of the color measurement process.

[0091] Furthermore, if the inspection unit 22 determines that the first color patch 111 of the first color chart 110 is abnormal, it inspects whether the second color patch 111 of the second color chart 110, which is of the same type as the first color patch 111, is abnormal. This configuration increases the likelihood that the color measurement process can be completed without reforming the color patches 111.

[0092] Furthermore, if the inspection unit 22 determines that both color patches 111 are abnormal, the instruction unit 24 instructs the image forming unit 5 to reform the color patches 111 in the empty areas on the surface of the recording medium 100 on which both color patches 111 are formed. This configuration allows for relatively increased efficiency of the color measurement process while suppressing consumption of the recording medium 100.

[0093] Furthermore, the instruction unit 24 instructs the image forming unit 5 to reform the color patches 111 on the second surface of the recording medium 100 on which the first color patch 111 and the second color patch 111 are formed. With this configuration, the color measurement process can be performed while suppressing the consumption of the recording medium 100.

[0094] Furthermore, the instruction unit 24 instructs the image forming unit 5 to reform the color patches 111 on a recording medium 100 different from the one on which the first and second color patches 111 are formed. This configuration makes it possible to prevent the color measurement process from becoming impossible if there is a problem with one of the recording media 100 on which the first and second color patches 111 are formed.

[0095] Furthermore, the instruction unit 24 causes a second inkjet head, which is different from the first inkjet head that formed the color patch 111, to reform the color patch 111. This configuration makes it possible to prevent the color measurement process from becoming impossible if there is a problem with the inkjet head that forms the color patch 111.

[0096] Furthermore, the instruction unit 24 instructs the image forming unit 5 to reshape the multiple color patches 111 based on the calculation results of the calculation unit 21. With this configuration, if an abnormality is found in the reshaped color patches 111, it is not necessary to reshape the color patches 111 again, thus suppressing the time required to complete the color measurement process.

[0097] Furthermore, the reading unit 6 is an in-line sensor located downstream of the image forming unit 5 in the transport direction. With this configuration, the reading of the color chart 110 by the reading unit 6 and the reshaping of the color patch 111 based on the result can be performed in a single flow, thereby shortening the time required to complete the color measurement process.

[0098] Furthermore, the inspection unit 22 compares the image data with the correct image data to detect the presence or absence of stains, defects, or streaks in the image data. With this configuration, by detecting the presence or absence of stains, defects, or streaks by the reading unit 6, abnormalities can be detected without stopping the transport unit 4, thereby suppressing a decrease in productivity.

[0099] [Other configurations] Although the present invention has been described in detail based on embodiments of the present invention, the present invention is not limited to the embodiments described above. It goes without saying that the present invention can be modified in various ways, including to a extent equivalent to the scope of the invention described in the claims.

[0100] For example, in the above description, the image forming apparatus 1 is exemplified as a so-called inkjet recording device in which the image forming unit 5 is equipped with an inkjet head, but it is not limited to this. For example, the image forming apparatus 1 may be a so-called laser printer in which the image forming unit 5 forms an image by an electrophotographic method. Thus, the present invention is applicable to various image forming apparatuses 1 that correct the image forming unit 5 by forming and reading a color patch 111.

[0101] Furthermore, although the above example illustrates a configuration in which the transport unit 4 transports the recording medium 100 and printed material 200 on a transport drum 43, the system is not limited to this configuration, and for example, a configuration in which the materials are transported by an endless belt may also be used.

[0102] Furthermore, although the above example illustrates an image forming apparatus 1 comprising a control unit 2, a transport unit 4, a reading unit 6, and a colorimetric unit 9, the present invention is not limited to this configuration. As stated above, the image forming apparatus 1 only needs to include at least an image forming unit 5, and the present invention is also applicable to an image forming system in which another device separate from the image forming apparatus 1 comprises other components excluding the image forming unit 5.

[0103] Furthermore, while the above discloses an example in which an HDD is used as a computer-readable medium for the program according to the present invention, the invention is not limited to this example. Portable recording media such as CD-ROMs can be used as other computer-readable media. In addition, carrier waves can be used as a medium for providing the data of the program according to the present invention via a communication line. [Explanation of Symbols]

[0104] 1. Image forming apparatus 2 Control Unit 21 Calculation Section 22 Inspection Department 23 Judgment section 24 Instruction section 25 Selection Section 4. Conveying section 43a Reversal mechanism 5 Image forming unit 6. Reading Unit 9 Color measurement section 100 recording media 110 Color Chart 111 Color Patches

Claims

1. The system comprises an image forming unit that forms an image on a recording medium, a reading unit that reads the image formed on the recording medium, a colorimetric unit that measures the color of the image formed on the recording medium, and a control unit. The control unit includes an inspection unit that checks whether each of the multiple color patches has an abnormality based on the image data of the multiple color patches acquired from the reading unit, A determination unit determines whether or not a color patch is capable of being measured by the color measurement unit, based on the inspection results of the inspection unit. The determination unit is instructed to cause the image forming unit to reshape only the color patches that the color measuring unit has determined cannot measure, An image forming apparatus equipped with the following features.

2. The control unit includes a calculation unit that calculates the number of color patches that can be formed on the recording medium. The image forming apparatus according to claim 1, wherein the calculation unit obtains the length of the recording medium in the transport direction and the length in the width direction perpendicular to the transport direction, and the length of the color chart composed of the plurality of color patches in the transport direction and the length in the width direction of the color chart, and calculates that a plurality of color charts can be formed if the length of the color chart in the transport direction is half or less of the length of the recording medium in the transport direction, or if the length of the color chart in the width direction is half or less of the length of the recording medium in the width direction.

3. The image forming apparatus according to claim 2, wherein the control unit, when it calculates that a plurality of color charts can be formed in the transport direction of the recording medium, causes the arrangement of the corresponding color patches among the plurality of color charts to differ in the width direction.

4. The image forming apparatus according to claim 2, wherein, if the inspection unit determines that a first color patch of a first color chart composed of a plurality of color patches is abnormal, it inspects whether a second color patch of the same type as the first color patch of a second color chart different from the first color chart is abnormal.

5. The image forming apparatus according to claim 4, wherein the instruction unit instructs the image forming unit to reform the color patches in the empty area on the first surface of the recording medium on which the first color patches and the second color patches are formed, if the inspection unit determines that the first color patch and the second color patch have an abnormality, and the determination unit determines that the first color patch and the second color patch are not color patches that can be measured by the colorimeter.

6. A reversal mechanism is provided downstream of the image forming section in the transport direction, which reverses the surface on which the image is formed on the recording medium and passes it through the image forming section again. The image forming apparatus according to claim 4, wherein the instruction unit instructs the image forming unit to reform the color patches on the second surface of the recording medium opposite to the first surface on which the first color patches are formed, if the inspection unit determines that the first color patch and the second color patch have an abnormality, and the determination unit determines that the first color patch and the second color patch are not color patches that can be measured by the colorimeter.

7. The image forming apparatus according to claim 4, wherein the instruction unit instructs the image forming unit to reform the color patches on a recording medium different from the recording medium on which the first and second color patches were formed, if the inspection unit determines that the first color patch and the second color patch have an abnormality, and the determination unit determines that the first and second color patches are not color patches that can be measured by the colorimeter.

8. The image forming unit comprises a plurality of inkjet heads, The image forming apparatus according to any one of claims 5 to 7, wherein the instruction unit causes a second inkjet head, which is different from the first inkjet head that formed the color patch, to reform the color patch.

9. The image forming apparatus according to any one of claims 5 to 7, wherein the instruction unit instructs the image forming unit to reform a plurality of color patches based on the calculation result of the calculation unit.

10. The image forming apparatus according to any one of claims 1 to 7, wherein the reading unit is an inline sensor provided downstream of the image forming unit in the transport direction.

11. The image forming apparatus according to any one of claims 1 to 7, wherein the inspection unit compares the image data with the correct image data to detect the presence or absence of stains, defects, or streaks in the image data.

12. An image forming apparatus comprising an image forming unit for forming an image on a recording medium, a reading unit for reading the image formed on the recording medium, and a colorimetric unit for measuring the color of the image formed on the recording medium, An inspection unit that checks whether each of the multiple color patches has an abnormality based on the image data of the multiple color patches obtained from the reading unit, A determination unit determines whether or not a color patch is capable of being measured by the color measurement unit, based on the inspection results of the inspection unit. The determination unit is instructed to cause the image forming unit to reshape only the color patches that the color measuring unit has determined cannot measure, An image forming system comprising the following features.

13. An image forming method using an image forming apparatus comprising: an image forming unit for forming an image on a recording medium; a reading unit for reading the image formed on the recording medium; a colorimetric unit for measuring the color of the image formed on the recording medium; and a control unit, The control unit performs an inspection step of checking whether each of the multiple color patches has an abnormality based on the image data of the multiple color patches acquired from the reading unit, A determination step is to determine whether or not the color patch is one that can be measured by the color measuring unit, based on the inspection results of the inspection step. The determination step includes an instruction step to cause the image forming unit to reform only the color patches that the color measuring unit has determined cannot measure, An image forming method comprising the following:

14. A computer for an image forming apparatus comprising: an image forming unit for forming an image on a recording medium; a reading unit for reading the image formed on the recording medium; and a colorimetric unit for measuring the color of the image formed on the recording medium, An inspection unit that checks whether each of the multiple color patches has an abnormality based on the image data of the multiple color patches obtained from the reading unit. A determination unit determines whether or not a color patch is capable of being measured by the color measurement unit, based on the inspection results of the inspection unit. A program that causes the determination unit to function as an instruction unit that causes the image forming unit to reshape only the color patches that the color measurement unit has determined cannot measure.

Images