JP2024046579A - printing device - Google Patents

Abstract

[Problem] To provide a technology that can reduce the amount of data to be processed when inspecting a print image printed on a print medium. [Solution] A printing device 1 includes a printing unit 20, a camera 40, and an image data output unit 50. The printing unit 20 is capable of printing a plurality of types of test patterns on a print medium 9. The camera 40 captures an image of the test pattern printed on the print medium 9, and outputs the obtained image data MD1 to the image data output unit 50. The image data output unit 50 reduces the amount of data for the image data MD1 output by the camera in accordance with the type of test pattern, and outputs the obtained image data MD2 to an inspection device 8. [Selected Figure] Figure 1

Description

The subject matter disclosed in this specification relates to a printing device.

Conventionally, there is known a printing device that ejects ink droplets from the nozzles of a print head to print on a print medium using an inkjet method. In this type of printing device, a print image formed on the print medium is captured by a camera, and the print image is inspected based on the image data obtained.

For example, Patent Document 1 describes a technology that makes it possible to determine with sufficient accuracy whether a printed image is a defective image (a truly defective image) based on captured image data obtained by capturing a print image output from a printing device onto a print medium.

JP 2021-005266 A

In recent years, there has been a trend for the amount of data to be processed per unit time to increase as printing speeds improve and the resolution of images to be inspected increases. As the amount of data to be processed increases, the processing burden on the hardware increases, and the specifications required for the hardware also become higher, which can lead to higher costs for inspecting printed images.

An object of the present invention is to provide a technique that can reduce the amount of data to be processed when inspecting a print image printed on a print medium.

In order to solve the above-mentioned problem, a first aspect is a printing device, which includes a printing section capable of printing a plurality of types of test patterns on a print medium, and a camera that outputs image data obtained by capturing the test pattern. The apparatus further includes an image data output unit capable of reducing the amount of data of the image data output by the camera according to the type of the test pattern and outputting the obtained image data.

In a second aspect of the printing apparatus of the first aspect, when the test pattern is a test pattern for checking ink ejection from each nozzle, the image data output section is configured to extract the image data from the image data. Outputs luminance data.

A third aspect is a printing device according to the first or second aspect, in which, when the test pattern is a front-back comparison test pattern for comparing the degree of agreement between the position of an image printed on a first side of the printing medium and the position of an image printed on a second side opposite the first side, the image data output unit outputs at least one plane data selected from red plane data, green plane data, and blue plane data extracted from the image data.

A fourth aspect is a printing device according to any one of the first to third aspects, in which the image data output unit outputs low-resolution image data in which the resolution of the image data is reduced.

A fifth aspect is a printing device according to any one of the first to fourth aspects, further comprising a print control unit that controls the printing unit, the print control unit outputs type information indicating the type of the test pattern to the image data output unit, and the image data output unit reduces the amount of data of the image data based on the type information output by the printing unit.

A sixth aspect is a printing device according to any one of the first to fifth aspects, in which the printing unit is capable of printing a test pattern including type information on the printing medium, the camera is capable of capturing an image of the type information, and the image data output unit reads the type information included in the image data and reduces the amount of data in the image data based on the type information that has been read.

A seventh aspect is a printing device according to any one of the first to sixth aspects, in which the image data output unit recognizes the area of a test pattern contained in the image data and the type of the test pattern by performing image recognition processing on the image data, and reduces the amount of data of the image data according to the type of the recognized test pattern.

An eighth aspect is the printing device according to any one of the first to seventh aspects, wherein the image data output unit is configured to reduce the number of bits per pixel with respect to the image data output by the camera. Printing equipment, including conversion circuits.

A ninth aspect is a printing device according to any one of the eighth aspects, in which the bit reduction circuit reduces the number of bits per pixel for the image data output by the camera when the test pattern is a pattern for front-back matching or a pattern for register adjustment.

A tenth aspect is a printing device according to the eighth or ninth aspect, in which, when the test pattern is a pattern for a shading check, the image data output unit outputs image data obtained without reducing the number of bits per pixel for the image data output by the camera.

According to the printing apparatuses of the first to tenth aspects, since the amount of data is reduced and outputted according to the type of test pattern, the amount of data to be output is reduced compared to the case where the image data is output as is, regardless of the test pattern. The amount can be reduced. Furthermore, the amount of data processing in an external device to which image data is input can be reduced.

According to the second aspect of the printing device, when the print image is a nozzle check test pattern, the brightness data is extracted and output to an external device, so that the amount of data to be output can be reduced and the nozzle check can be appropriately performed based on the brightness data.

According to the printing device of the third aspect, when the printed image is a test pattern for back side verification, plain data of a specific color is extracted and output to an external device, so the amount of data to be output can be reduced, and the Back side verification can be performed appropriately based on color plain data.

According to the printing apparatus of the fourth aspect, the amount of data can be reduced by lowering the resolution of image data.

According to the printing device of the fifth aspect, the amount of data can be reduced based on the type information output by the print control section.

The printing device of the sixth aspect can reduce the amount of data based on the type information read from the image data.

According to the seventh aspect of the printing device, the type of image data can be identified directly from the image data.

According to the printing device of the eighth aspect, the amount of data can be reduced by reducing the number of bits.

According to the printing device of the ninth aspect, when the test pattern is a pattern for nozzle checking, a pattern for front/back comparison, or a pattern for register adjustment, the number of bits of image data is reduced, so the amount of data is reduced. can.

According to the printing apparatus of the tenth aspect, shading check can be performed based on image data with a high bit number that has not been reduced in bit number.

1 is a diagram illustrating a configuration of a printing apparatus according to a first embodiment. FIG. 3 is a diagram showing the contents of a table that associates types of print images with output patterns. FIG. 3 is a diagram showing the operation of the printing device during printing. FIG. 3 is a diagram showing the configuration of a printing device according to a second embodiment. 4 is an example of a nozzle check pattern. 13 is an example of a front and back matching pattern. 4 is an example of a shading correction pattern. FIG. 13 is a diagram showing the contents of a table associating types of print images with output patterns according to the third embodiment. FIG. 7 is a diagram showing a block diagram of an image output unit according to a third embodiment. FIG. 7 is a diagram showing the operation of a printing apparatus according to a third embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Note that the components described in this embodiment are merely examples, and are not intended to limit the scope of the present invention to those components. In the drawings, the dimensions and numbers of each part may be exaggerated or simplified as necessary for ease of understanding.

<1. First embodiment>
1 is a diagram showing the configuration of a printing device 1 according to the first embodiment. The printing device 1 includes a transport unit 10, a printing unit 20, a print control unit 30, a camera 40, and an image data output unit 50.

The printing device 1 forms an image on the print surface of the print medium 9 by ejecting ink droplets (hereinafter referred to as "ink droplets") onto the print medium 9 using an inkjet method. In this example, the print medium 9 is in the form of a long strip (web). The printing medium 9 is, for example, printing paper, a resin film, or a metal foil.

The transport unit 10 continuously transports the print medium 9 from the upstream side to the downstream side in a roll-to-roll manner along a predetermined transport path. Specifically, the transport unit 10 has a pay-out roller 11, multiple transport rollers 12, and a wind-up roller 13. The pay-out roller 11, each of the transport rollers 12, and the wind-up roller 13 can rotate about an axis parallel to the width direction of the print medium 9.

The pay-out roller 11 continuously pays out the print medium 9 wound in a roll on the outer circumferential surface of the pay-out roller 11. The multiple transport rollers 12 are each positioned at a predetermined position on the transport path. Each transport roller 12 supports the print medium 9 paid out from the pay-out roller 11 from the back side opposite the printed surface. The wind-up roller 13 winds up the print medium 9 stretched across the multiple transport rollers 12 into a roll and collects it.

The conveyance unit 10 has a rotation drive unit such as a motor that rotates the take-up roller 13. Note that the conveyance unit 10 may include a rotation drive unit that rotates some or all of the feed roller 11 or the plurality of conveyance rollers 12.

The transport unit 10 includes a movement detection unit 15 that detects the movement of the print medium 9. The movement detection unit 15 is composed of a rotary encoder that detects the amount of rotation (rotation angle) of the transport roller 12. The movement detection unit 15 outputs a pulse signal to the print control unit 30 each time the transport roller 12 rotates a predetermined angle.

The printing unit 20 prints an image on a first surface 91, which is the printing surface of the print medium 9 transported in a first direction (direction X shown by an arrow in FIG. 1) by the transport unit 10. The printing unit 20 has a plurality of print heads 21 that eject ink droplets. In this example, a print head 21 that ejects black (K) ink droplets, a print head 21 that ejects cyan (C) ink droplets, a print head 21 that ejects M (magenta) ink droplets, and a print head 21 that ejects yellow (Y) ink droplets are arranged at intervals from one another in the first direction.

The color of ink ejected by each print head 21 can be changed as desired. The printing unit 20 may also have a print head 21 that ejects ink droplets of a color other than K, C, M, and Y. It is not essential that the printing unit 20 has multiple print heads 21, and the printing unit 20 may have only one print head 21.

On the surface of the print head 21 facing the first surface 91 of the print medium 9, multiple ejection nozzles (not shown) that eject ink droplets are arranged in a second direction Y (width direction of the print medium 9) that is approximately perpendicular to the first direction X. The multiple ejection nozzles are arranged in the width direction of the print medium 9. The range in which the print head 21 can eject ink droplets (printable range) covers the entire width direction of the print medium 9. The printing device 1 is a so-called single-pass type printing device in which each print head 21 ejects ink droplets to record a print image M1 on the print medium 9 while the print medium 9 passes under the multiple print heads 21 only once.

The print control unit 30 controls the print unit 20. The print control unit 30 is, for example, a computer equipped with a processor such as a CPU, a memory such as a RAM, and an auxiliary storage device such as a hard disk drive. The print control unit 30 may be configured with a dedicated electronic circuit such as an application specific semiconductor integrated circuit (ASIC).

The print control unit 30 controls the ejection of ink droplets from each nozzle in each print head 21 based on the image data to be printed on the print medium 9 and the amount of movement of the print medium 9 (the pulse signal output by the movement detection unit 15).

The print control unit 30 outputs the type information C1 to the image data output unit 50 and the inspection device 8. Type information C1 is data indicating the type of print image M1 included in image data MD1 acquired by camera 40.

Camera 40 is equipped with an image sensor consisting of imaging elements such as a CCD or CMOS, and captures the print image M1 using the image sensor. The image sensor may be an area sensor consisting of imaging elements arranged in a matrix of multiple rows and multiple columns, or a line sensor consisting of imaging elements arranged in a straight line. Camera 40 outputs image data MD1 obtained by imaging to image data output unit 50.

The image data output unit 50 recognizes the type of print image M1 based on the received type information CI. Next, the image data output unit 50 applies the recognized type of print image M1 to a table T1 to be described later, thereby obtaining an output pattern corresponding to the type of print image M1. Then, the image data output unit 50 executes data processing to reduce the data amount of the image data MD1 according to the output pattern, and obtains processed image data MD2. The image data output unit 50 then outputs the obtained image data MD2 to the inspection device 8. The image data output unit 50 is composed of, for example, a circuit board. The output pattern is set in advance for each type (image pattern) of the print image M1 printed by the printing unit 20. Therefore, the image data output unit 50 outputs image data MD2 obtained by processing to reduce the amount of data of the image data MD1, depending on the type of the print image M1.

Figure 2 shows the contents of table T1, which associates the type of print image M1 with the output pattern. The printing unit 20 is capable of printing various test patterns as the print image M1. The types of various test patterns specifically include "nozzle check patterns," "shading check patterns," "registration adjustment patterns," and "front and back verification marks," as shown in Figure 2.

The "nozzle check pattern" shown in FIG. 2 is a test pattern for checking the ejection of ink droplets from each nozzle of the print head 21. In FIG. 2, the output pattern for the nozzle check pattern is set to "brightness data". The brightness data is image data represented by the brightness value indicated by the image data MD1. When the image data MD1 is a nozzle check pattern, the image data output unit 50 outputs the brightness data extracted from the image data MD1 to the inspection device 8 as image data MD2. The inspection device 8 then performs image inspection for a nozzle check based on the brightness data.

The "shading check pattern" shown in FIG. 2 is a test pattern for adjusting the shading between the plurality of print heads 21. In FIG. 2, the output pattern for the shading check pattern is set to "plain data." The plane data is either red plane data, green plane data, or blue plane data indicated by image data MD1. When the image data MD1 is a shading check pattern, the image data output unit 50 outputs plain data of a specific color extracted from the image data MD1 to the inspection device 8 as image data MD2.

The "registration adjustment pattern" shown in FIG. 2 is a test pattern for correcting misregistration (misalignment between colors). The "front/back verification mark" is a test pattern for verifying the degree of agreement between the position of an image printed on the first side 91 of the print medium 9 and the position of an image printed on the second side 92 of the print medium 9, which is opposite the first side 91. In FIG. 2, the output patterns for these test patterns are also set in the "plain data". That is, when the image data MD1 is one of these test patterns, the plain data of a specific color extracted from the image data MD1 is output as image data MD2.

In this way, by the image data output unit 50 outputting luminance data or plane data of a specific color, the amount of data output to the inspection device 8 can be significantly reduced compared to when the image data output unit 50 outputs the image data MD1 as is.

The "GUI display image" shown in FIG. 2 is an image to be displayed on the display 81 equipped to the inspection device 8. In FIG. 2, the output pattern corresponding to the GUI display image is set to "low resolution data". The low resolution data is image data with a reduced resolution of the image data MD1. By the image data output unit 50 outputting the low resolution data as image data MD2, the amount of data output to the inspection device 8 can be significantly reduced compared to when the image data MD1 is output as is.

The "print quality inspection image" is an image for checking the print quality of the print image M1. The output pattern of the print quality inspection image is "RGB image data" or "YCC converted image data". "RGB image data" is an image composed of all of the red plane data, green plane data, and blue plane data indicated by the image data MD1. "YCC converted image data" is an image obtained by converting an RGB image into the YCbCr format. For this reason, when the image data MD1 is a print quality inspection image, the image data output unit 50 outputs to the inspection device 8 image data MD2 indicating an RGB image or a YCC converted image in which the amount of data from the image data MD1 is hardly reduced.

The inspection device 8 shown in FIG. 1 is communicably connected to the image data output section 50 of the printing device 1. The inspection device 8 is, for example, a computer equipped with a processor such as a CPU, a memory such as a RAM, and an auxiliary storage device such as a hard disk drive. The printing device 1 and the inspection device 8 constitute a printing system.

The inspection device 8 inspects the print image M1 indicated by the image data MD2 based on the image data MD2 output by the image data output unit 50. The type of inspection to be performed by the inspection device 8 is determined based on the type information C1 output by the print control unit 30. For this reason, the type information C1 can also be regarded as inspection type information indicating the type of inspection. For example, if the type of the print image M1 is a nozzle check pattern, the inspection device 8 inspects the nozzle check based on the image data MD2 (e.g., luminance data). If the type of the print image M1 is a shading check pattern, the inspection device 8 performs a shading check based on the image data MD2 (e.g., plain data). If the type of the print image M1 is a review adjustment pattern, the inspection device 8 performs a register adjustment based on the image data MD2 (e.g., plain data). If the type of the print image M1 is a front-back matching mark, the inspection device 8 performs front-back matching based on the image data MD2 (e.g., plain data). Furthermore, if the type of print image M1 is a print quality inspection image, the print quality is inspected based on image data MD2 (e.g., RGB image data or YCbCr converted image data). Furthermore, if the type of print image M1 is a GUI display image, the inspection device 8 displays the image data MD2 (e.g., low-resolution image data) on the display 81.

Note that it is not essential that the type information C1 is output from the print control unit 30 to the inspection device 8. For example, the image data output unit 50 may output the type information C1 to the inspection device 8 together with the image data MD2.

<Operation of printing device>
FIG. 3 is a diagram showing the operation of the printing apparatus 1 during printing. In the printing device 1, when printing is started, the camera 40 captures the print image M1 printed by the printing unit 20 (step S1). As described above, the camera 40 outputs the image data MD1 obtained by capturing the print image M1 to the image data output unit 50. The image data output unit 50 also acquires type information C1 corresponding to the print image M1 printed by the printing unit 20 (step S2).

After step S2, the image data output unit 50 determines the output pattern of the image data MD2 to be output based on the acquired type information C1 (steps S3, S4, S5). That is, if the output pattern is plain data (Yes in step S3), the image data output unit 50 extracts plain data of a specific color from the image data MD1 (step S6). Furthermore, if the output pattern is brightness data (Yes in step S4), the image data output unit 50 extracts the brightness data from the image data MD1 (step S7). Furthermore, if the output pattern is low resolution data (Yes in step S5), the image data output unit 50 converts the image data MD1 into a low resolution image (step S8). If the output pattern is neither plain data, brightness data, nor low resolution data (No in steps S3, S4, S5), the image data output unit 50 converts the image data MD1 into RGB image data (or YCbCr converted image data). ) (step S9).

The image data output unit 50 outputs the image data MD2 obtained by step S6, S7, S8 or S9 to the inspection device 8 (step S10). Then, when all printing is completed (Yes in step S11), the printing device 1 ends the printing process. On the other hand, when the printing process is not completed, the printing device 1 executes step S1 again.

As described above, according to the printing apparatus 1 of the present embodiment, the image data output unit 50 is configured such that the type of the print image M1 is an image pattern other than the print quality inspection image (various test patterns and GUI display images). In this case, image data MD2 whose data amount has been reduced with respect to image data MD1 is output to the inspection device 8. Thereby, the amount of output data can be reduced compared to the case where the image data MD1 is output as is regardless of the type of the print image M1. Thereby, the amount of data communication between the image data output section 50 and the inspection device 8 can be reduced. Furthermore, in the inspection device 8, the amount of data to be processed can be reduced. Therefore, the hardware specifications can be lowered and the device cost can be reduced.

<2. Second embodiment>
Next, a second embodiment will be described. In the following description, elements having the same functions as elements already described will be given the same reference numerals or reference numerals with an additional alphabetical character, and detailed description thereof may be omitted.

Figure 4 is a diagram showing the configuration of a printing device 1A according to the second embodiment. In the printing device 1A, instead of the printing control unit 30 outputting the type information C1 to the image data output unit 50, the printing control unit 30 controls the printing unit 20 to print an image (for example, a one-dimensional code or a two-dimensional code) indicating the type information C1 together with the print image M1. Then, the camera 40 captures an image of the type information C1 together with the print image M1. As a result, the image data MD1 captured by the camera 40 can include an image indicating the type information C1 together with the print image M1. The image data output unit 50 recognizes the type of the read image data MD1 by reading the type information C1 included in the image data MD1. Next, a process is performed to reduce the data amount of the image data MD1 according to an output pattern corresponding to the type of the image data MD1. Then, the obtained image data MD2 is output to the inspection device 8. Also, the image data output unit 50 outputs the read type information C1 together with the image data MD2 to the inspection device 8.

The inspection device 8 inspects the print image M1 based on the image data MD2 and type information C1 output by the image data output unit 50. Note that it is not essential that the type information C1 is output from the image data output unit 50 to the inspection device 8. For example, the print control unit 30 may output the type information C1 to the inspection device 8.

Also in the printing device 1A, when the print image M1 is various test patterns or GUI display images, the image data output unit 50 reduces the data amount of the image data MD1 according to the output pattern corresponding to the type information C1, The obtained image data MD2 (luminance data, plain data of a specific color, or low resolution image) is output to the inspection device 8. Therefore, the amount of data can be reduced based on the type information C1 read from the image data MD1.

Note that the image data output unit 50 may directly recognize the type of the image data MD1 by performing image recognition processing on the read image data MD1. In this case, there is no need to print an image (for example, a one-dimensional code or two-dimensional code) indicating the type information C1 near the print image M1, so it is possible to expand the effective printing area of the print medium 9.

FIG. 5 is an example of a nozzle check pattern. A test pattern TP1 for nozzle checking is printed on the print medium 9 by the print head 21. In the test pattern TP1, the lines extending in the first direction X printed by the plurality of nozzles N1 to N60 arranged in the second direction Y of the print head 21 are referred to as lines L1 to L60, respectively. The test pattern TP1 consists of 15 sets of four nozzles of the print head 21 (15 sets of nozzles N1 to N4, N5 to N8, N9 to N12, . . . , N53 to N56, N57 to N60). In each set, ink is ejected with the ejection timing shifted from one nozzle to another, thereby forming a step-like printed pattern.

In this way, the test pattern TP1 for nozzle checks is a pattern that includes multiple lines L1 to L60 that extend in the first direction X. By performing image recognition processing on the image data MD1, the image data output unit 50 can recognize an area in the image data MD1 that has such characteristics (a pattern that extends in the first direction X and includes multiple lines that occur repeatedly in the second direction Y) as a nozzle check pattern.

Figure 6 is an example of a front-back matching pattern. A test pattern TP2 for front-back matching is printed on the printing medium 9 by the print head 21. The test pattern TP2 is shifted in the second direction Y from the printing area of the actual image 70 and is printed near the edge of the printing medium 9. The test pattern TP2 is a solid pattern of constant high density. Typically, the size of the test pattern TP2 is smaller than the actual image 70. The image data output unit 50 performs image recognition processing on the image data MD1, and can recognize an area in the image data MD1 having such characteristics (a solid pattern of constant high density, a relatively small pattern printed near the edge of the printing medium 9) as a front-back matching pattern.

Figure 7 shows an example of a pattern for shading correction. A test pattern TP3 for shading correction is printed on the printing medium 9 by the print head 21. The test pattern TP3 is composed of multiple band-shaped images 71-74 that are short in the first direction X and long in the second direction Y. The multiple band-shaped images 71-74 are all solid patterns of a constant density, and the density levels are different from one another. By performing image recognition processing on the image data MD1, the image data output unit 50 can recognize an area in the image data MD1 that has such characteristics (multiple solid patterns of different densities that are short in the first direction X and long in the second direction Y) as a pattern for shading correction.

The image data output unit 50 executes image recognition processing using the same method for the register adjustment pattern, the GUI display image, and the print quality inspection image, thereby recognizing the area and image of these images included in the image data MD1. It is possible to automatically recognize the type of

As described above, the image data output unit 50 can recognize the region of the test pattern included in the image data MD1 and the type of the test pattern by performing image recognition processing on the image data MD1. Then, by applying the recognized test pattern type to the table T1, the output pattern type of the test pattern is obtained, and the output pattern is used to perform processing to reduce the amount of image data MD1, and is output to the inspection device 8. be able to. Note that the image data output unit 50 may also output the test pattern area and test pattern type acquired by the image recognition process to the inspection device 8.

<3. Third embodiment>
The image data output unit 50 may output image data MD2, the amount of data of which has been reduced by reducing the number of bits per pixel (hereinafter simply referred to as "bit number") of the image data MD1 output by the camera 40, to the inspection device 8. The number of bits of an image is the number of bits used per pixel to express the color depth (color depth) or degree of color of the image. The more the number of bits, the more detailed the color or shading information of the image can be expressed, but the file size also becomes larger. In the following description, it is assumed that the camera 40 outputs 10-bit image data MD1, that is, image data MD1 in which each color of RGB is expressed by 10 bits, to the image data output unit 50.

Figure 8 is a diagram showing the contents of table T2, which associates the type of print image M1 with the output pattern according to the third embodiment. "Output bit count" is the number of bits per pixel of the image data MD2 output by the image data output unit 50.

In table T2 shown in FIG. 8, when the type of print image M1 is a nozzle check pattern, the output pattern is set to brightness data. When the type of print image M1 is a shading check pattern, the output pattern is set to 10-bit RGB data. When the type of print image M1 is a register adjustment pattern, the output pattern is set to 8-bit RGB data. When the type of print image M1 is a front-back comparison mark, the output pattern is set to 8-bit G plane data. When the type of print image M1 is an image for GUI display, the output pattern is set to 8-bit RGB data (low resolution). When the type of print image M1 is an image for print quality inspection, it is set to 8-bit RGB data. That is, when the type of the print image M1 is a register adjustment pattern, front/back comparison mark, GUI display image, or print quality inspection image, the image data output unit 50 outputs the 10-bit image output by the camera 40. Convert data MD1 to 8-bit image data MD2. The number of bits may be reduced by, for example, removing the lower two bits of the 10 bits to obtain 8 bits.

Further, in table T2, when the print image M1 is a shading pattern, the number of output bits is set to 10 bits. That is, when the type of print image M1 is a shading check pattern, the image data output unit 50 outputs 10-bit image data MD2 for 10-bit image data MD1. In this way, when the type of print image M1 is a shading check pattern, the process of reducing the number of bits is not performed.

FIG. 9 is a block diagram showing details of the image data output section 50 according to the third embodiment. The image data output section 50 includes a switching circuit 51, a bit reduction circuit 52, and an image data processing circuit 53.

Image data MD1 output from the camera 40 is input to the switching circuit 51, and the image data MD1 is selectively output to the bit reduction circuit 52 or the image data processing circuit 53 according to the instruction of the type information CI. That is, when the type information CI indicates either a nozzle check pattern or a shading check pattern, the image data MD1 is output to the image data processing circuit 53. On the other hand, if the type information CI indicates any one of the register adjustment pattern, front and back matching pattern, and GUI display image, the image data MD1 is transmitted to the bit reduction circuit 52. The bit reduction circuit 52 degenerates the received image data MD1 (10 bits) into 8 bits and outputs 8 bits of RGB data as image data MD11.

The image data processing circuit 53 receives the above-mentioned 10-bit image data MD1 and 8-bit image data MD11. Then, in accordance with the instruction of the type information CI, these are appropriately processed and output to the inspection device 8 as processed image data MD2. That is, if the type information CI indicates a nozzle check pattern, the image data MD1 is converted into luminance data. If the type information CI indicates a shading check pattern, no special processing is performed on the image data MD1. If the type information CI indicates a registration adjustment pattern, no special processing is performed on the image data MD11. If the type information CI indicates a front/back collation mark pattern, processing is performed to extract only the G plane from the image data MD11 (RGB data). If the type information CI indicates an image for GUI display, processing is performed to reduce the resolution of the image data MD11. If the type information CI indicates an image for print quality inspection, no special processing is performed on the image data MD11, or YCC conversion processing is performed.

Figure 10 is a diagram showing the operation of the printing device 1 according to the third embodiment. Steps S1 and S2 shown in Figure 10 are common to steps S1 and S2 of the first embodiment shown in Figure 3, respectively. However, this embodiment differs from the first embodiment in the processing after step S2. Below, a description of the common parts will be omitted, and the different parts will be described in detail.

After acquiring type information C1 corresponding to print image M1 in step S2, the image data output unit 50 determines whether it is necessary to reduce the number of bits of image data MD1 based on the type of print image M1 indicated by the acquired type information C1 and the definition of table T2 (step S21). For example, if the type of print image M1 indicated by type information C1 is a registration adjustment pattern, a front/back comparison mark, an image for GUI display, or a print quality inspection image, in step S21, the image data output unit 50 determines that it is necessary to reduce the number of bits. If the type of print image M1 indicated by type information C1 is a shading check pattern, in step S21, the image data output unit 50 determines that it is not necessary to reduce the number of bits.

If it is determined in step S21 that it is necessary to reduce the number of bits (Yes in step S21), the image data output unit 50 reduces the number of bits of the image data MD1 output by the camera 40 (step S22). That is, the image data output unit 50 reduces the number of bits of the image data MD1 from 10 bits to 8 bits, and sets it as image data MD11. Then, the image data output unit 50 executes the processing from step S23 onwards. That is, if the output pattern is plain data, the process advances to step S24, and processing for extracting G plane data from the image data MD11 is executed. In the next step S25, this G plane data is output to the inspection device 8 as image data MD2 processed for front and back comparison marks.

If the answer is No in step S23, then in the next step S26 it is determined whether the output pattern is luminance data. If the answer is Yes in step S26, then in the next step S27 the image data MD11 is converted from RGB to YCC to generate luminance data. Note that this luminance data may be output to the inspection device 8 as image data MD2 processed for print quality inspection in step S25.

If it is determined No in step S26, it is determined in the next step S28 whether the output pattern is low resolution data. If it is determined Yes in step S28, the image data MD11 is converted to a low resolution in the next step S29, and low resolution RGB data (8 bits) is generated. In step S25, this data is output to the inspection device 8 as image data MD2 processed for GUI display.

If it is determined No in step S28, the process proceeds to step S25, where the image data MD11 (8-bit RGB data) is processed as image data MD2 processed as a register adjustment pattern or image data MD2 processed for print quality inspection. It is output to the inspection device 8.

The process returns to step S21 to determine whether or not the number of bits needs to be reduced. If it is determined No in this step S21, the process advances to step S30. In step S30, it is determined whether the output pattern is luminance data. If it is determined Yes in step S30, the image data MD1 is RGB-YCC converted to generate luminance data in the next step S31. In step S25, this brightness data is output to the inspection device 8 as image data MD2 processed for the nozzle check pattern.

If it is determined No in step S30, the process proceeds to step S25, and the 10-bit RGB data is output to the inspection device 8 as image data MD2 processed as a shading check pattern. The 10-bit RGB data may be output to the inspection device 8 as image data for print quality inspection.

When performing a shading check, the inspection device 8 checks the variation in the amount of ink ejected between the multiple ejection nozzles of the print head 21 based on the shading indicated by the image data MD2 output by the image data output unit 50. The shading check is performed based on image data MD2 that has a high bit count, i.e., image data in which the number of bits has not been reduced, and in which the shading is expressed in detail. This allows the variation in shading to be inspected with high precision, and therefore the variation in the amount of ink ejected between the ejection nozzles to be inspected with high precision.

If the shading check shows that the amount of variation is equal to or greater than the specified value, the inspection device 8 may display an alarm on the display 81. In addition, the inspection device 8 generates a correction signal for each ejection nozzle to correct variations in ejection amount, and transmits the correction signal to the print control unit 30. The print control unit 30 drives each ejection nozzle based on the correction signal transmitted by the inspection device 8. This allows the print head 21 to form an image with uniform density on the print medium 9.

If the type of print image M1 is a registration pattern, a front/back verification mark, a GUI display image, or a print quality inspection image, step S21 determines that the number of bits needs to be reduced, and step S22 reduces the number of bits of the image data MD1 output by the camera 40 from 10 bits to 8 bits. Then, in step S24, S27, or S29, image data conversion according to the purpose is performed, and the image data MD2 is output to the inspection device 8. In this case, the amount of output data can be reduced compared to when 10-bit image data MD2 is output to the inspection device 8. This makes it possible to reduce the amount of data communication between the image data output unit 50 and the inspection device 8. Also, in the inspection device 8, the amount of data to be processed can be reduced. This makes it possible to lower the hardware specifications and reduce device costs.

Furthermore, in the third embodiment, it is not essential that steps S23, S24, and steps S26 to S31 shown in FIG. 10 be performed. That is, the image data output unit 50 may reduce the number of bits of the image data MD1 in accordance with the type of print image M1 in steps S21 and S22, and then output the image data MD1 with the reduced number of bits to the inspection device 8 as image data MD2.

Although this invention has been described in detail, the above description is illustrative in all aspects, and the invention is not limited thereto. It is understood that countless variations not illustrated can be envisaged without departing from the scope of the invention. The configurations described in each of the above embodiments and modified examples can be appropriately combined or omitted as long as they do not contradict each other.

1,1A Printing device 9 Printing medium 20 Printing section 21 Printing head 30 Printing control section 40 Camera 50 Image data output section 52 Bit reduction circuit 91 First page 92 Second page C1 Type information M1 Print image (test pattern)
MD1, MD2 image data

Claims (10)

A printing device,
A printing unit that can print multiple types of test patterns on print media;
a camera that outputs image data of the test pattern;
an image data output unit capable of reducing the amount of data of the image data output by the camera according to the type of the test pattern and outputting the obtained image data;
A printing device comprising: 2. The printing device according to claim 1,
A printing device, wherein when the test pattern is a test pattern for checking ink ejection from each nozzle, the image data output unit outputs luminance data extracted from the image data. 3. The printing device according to claim 1,
A printing device in which, when the test pattern is a front-back comparison test pattern for comparing the degree of correspondence between the position of an image printed on a first side of the printing medium and the position of an image printed on a second side opposite the first side, the image data output unit outputs at least one plane data selected from red plane data, green plane data, or blue plane data extracted from the image data. The printing device according to claim 1 or 2,
The image data output unit is a printing device that outputs low-resolution image data obtained by lowering the resolution of image data. The printing device according to claim 1 or 2,
a printing control unit that controls the printing unit;
Furthermore,
The print control unit outputs type information indicating the type of the test pattern to the image data output unit,
The image data output unit is a printing device that reduces the amount of image data based on the type information output by the printing unit. 3. The printing device according to claim 1,
the printing unit is capable of printing a test pattern including type information on the printing medium;
The camera is capable of capturing an image of the type information,
The image data output unit reads the type information included in the image data, and reduces the amount of data of the image data based on the read type information. 3. The printing device according to claim 1,
A printing device in which the image data output unit recognizes the area of a test pattern contained in the image data and the type of the test pattern by performing image recognition processing on the image data, and reduces the amount of data of the image data according to the type of the recognized test pattern. 3. The printing device according to claim 1,
A printing device, wherein the image data output section includes a bit-lowering circuit that reduces the number of bits per pixel for the image data output by the camera. 9. The printing device according to claim 8,
A printing device, wherein the bit reduction circuit reduces the number of bits per pixel for the image data output by the camera when the test pattern is a pattern for front-back comparison or a pattern for register adjustment. 10. The printing device according to claim 8 or 9,
When the test pattern is a pattern for a shading check, the image data output unit outputs image data obtained without reducing the number of bits per pixel for the image data output by the camera.

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