Inkjet printing device

Abstract

This makes it easier to adjust the timing of the imaging trigger. [Solution] The inkjet printing apparatus 1 includes an imaging unit 31 that captures a drawing pattern formed on an object to be printed with ink and generates an image; an inspection machine 3 that performs image inspection of the drawing pattern using the image; a storage unit 41 that stores region information indicating an area on the object to be printed where the drawing pattern can be captured, which is determined based on field-of-view information defining the imaging field of view of the imaging unit 31; a detection sensor 9 that detects the arrival of the object to be printed; and a control unit 40 that determines the timing of issuing an imaging trigger based on the region information, the position of the elements, and the detection timing of the detection sensor.

Description

Technical Field

[0001] The present disclosure relates to an inkjet printing apparatus.

Background Art

[0002] For example, a drop-on-demand (DOD) type inkjet printing apparatus that discharges ink onto a packaging material such as cardboard for printing is known (see, for example, Patent Document 1). Further, a technique for photographing a pattern drawn by a DOD type inkjet printing apparatus with a camera and performing alignment or the like using the obtained photographed image is also known (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is conceivable to photograph a pattern drawn by an inkjet printing apparatus with a camera and perform inspection of the pattern or the like using the obtained photographed image. In this case, it is necessary to issue an imaging trigger at an optimal timing when the drawn pattern enters the field of view of the camera. However, in order to make the timing of issuing the imaging trigger optimal, it is necessary to actually perform a test drawing of the pattern on the object to be drawn and adjust the timing of the imaging trigger while observing the object to be drawn that has been test drawn. Such timing adjustment work is complicated and time-consuming, and it is not easy to adjust the timing of the imaging trigger unless one is a skilled person who is proficient in both the inkjet printing apparatus and the camera.

[0005] This disclosure is made in view of the above, and its purpose is to facilitate the adjustment of the timing of the imaging trigger. [Means for solving the problem]

[0006] To achieve the above objective, an inkjet printing apparatus according to one aspect of the present disclosure includes: an ink storage unit for storing ink; an ejection unit for ejecting ink supplied from the ink storage unit toward an object to be printed which is transported by a transport device; an imaging unit for imaging a drawing pattern formed on the object to be printed by the ink ejected from the ejection unit and generating an image; an image inspection unit for performing an image inspection of the drawing pattern using the image generated by the imaging unit; a storage unit for storing area information indicating an area on the object to be printed which can be imaged, determined based on field-of-view information defining the imaging field of view of the imaging unit; a display unit for displaying a setting surface corresponding to a drawing area on the object to be printed which is drawn by the ink ejected from the ejection unit; a setting unit for arranging elements according to a drawing pattern on the setting surface displayed on the display unit and setting the drawing content based on user operation; a detection sensor for detecting the arrival of an object to be printed which is transported by the transport device; and a control unit for determining the timing of issuing an imaging trigger based on the area information stored in the storage unit, the positions of the elements arranged on the setting surface by the setting unit, and the detection timing of the detection sensor.

[0007] With this configuration, an image capture trigger with the optimal timing for inspecting the drawing pattern is automatically generated based on the area information stored in the memory unit, the positions of the elements placed on the setting surface by the setting unit, and the detection timing of the detection sensor that detects the object to be drawn. As a result, the imaging unit can generate an image that allows for image inspection of the drawing pattern without the user having to perform complicated adjustment work such as adjusting the timing of the image capture trigger while looking at the object to be drawn as a test. [Effects of the Invention]

[0008] As explained above, when performing image inspection of a drawing pattern formed on an object to be drawn on, the timing of the imaging trigger for capturing the drawing pattern can be easily adjusted. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the overall configuration of an inkjet printing apparatus according to an embodiment of the present invention. [Figure 2] Figure 2 is a block diagram of an inkjet printing device. [Figure 3] Figure 3 is a plan view showing an example of the installation of the drawing machine and inspection machine. [Figure 4] Figure 4 is a front view showing an example of the installation of the drawing machine and inspection machine. [Figure 5] Figure 5 is a flowchart showing an example of the procedure for setting up drawing and inspection. [Figure 6] Figure 6 shows an example of a settings screen. [Figure 7] Figure 7 shows an example of a job list display screen. [Figure 8] Figure 8 shows an example of a screen displaying a list of drawing elements. [Figure 9] Figure 9 shows an example of the block addition screen. [Figure 10] Figure 10 shows an example of the block editing screen. [Figure 11] Figure 11 shows an example of an adjustment screen. [Figure 12] Figure 12 is a conceptual diagram that identifies the edges of a drawing pattern. [Figure 13] Figure 13 shows an example of the display configuration upstream and downstream of the nearest point. [Figure 14] Figure 14 is a diagram illustrating the procedure for calculating the imaging delay time. [Figure 15] Figure 15 shows an example of an captured image. [Figure 16] Figure 16 shows an example of an input screen when the imaging trigger is linked to the drawing trigger. [Figure 17] FIG. 17 is an example of an input screen when the imaging trigger is not coordinated with the drawing trigger. [Figure 18] FIG. 18 is an example of an input screen when the workpiece is moving at a constant speed. [Figure 19] FIG. 19 is an example of an input screen when an encoder is used. [Figure 20] FIG. 20 is an example of an inspection setting screen. [Figure 21] FIG. 21 is a flowchart during the operation of an inkjet printing apparatus. [Figure 22] FIG. 22 is a timing chart of a detection sensor, a drawing machine, and an inspection machine.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0011] FIG. 1 is a diagram showing the overall configuration during the operation of an inkjet printing apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a block diagram of the inkjet printing apparatus 1. The inkjet printing apparatus 1 includes, for example, a drawing machine 2, an inspection machine 3, a controller 4, and an operation terminal 5.

[0012] The drawing machine 2 is a part that executes drawing processing on an object to be drawn and is configured separately from the controller 4. The inspection machine 3 is a part that determines the quality of the drawing state executed on the object to be drawn by the drawing machine 2 and is configured separately from the controller 4. Since the inkjet printing apparatus 1 according to the present embodiment includes the drawing machine 2 and the inspection machine 3, it is an inkjet printing apparatus that discharges ink for drawing information on an object and determines the quality of the drawing state by imaging.

[0013] Controller 4 is the part that controls the drawing machine 2 and the inspection machine 3, and can also be called a control device, control unit, etc. The operating terminal 5 consists of a personal computer or the like, and is the part in which the user performs tasks such as inputting drawing information, making various settings, selections, and confirmations. The operating terminal 5 includes a terminal-side display unit 5a, which consists of, for example, a liquid crystal display, and a terminal-side operation unit 5b, which consists of a keyboard, mouse, pointing device, etc.

[0014] The above configuration example is just one example, and the present invention is not limited to the above configuration example. That is, the controller 4 may be incorporated into the operation terminal 5 or into the drawing machine 2. Alternatively, the operation terminal 5 may function as the controller 4. Figures 1 and 2 show an external device 6 consisting of a programmable logic controller (PLC) or the like, and this external device 6 is connected to the controller 4 in a communicative manner. Control signals output from the external device 6 are input to the controller 4. The external device 6 may be a device that constitutes part of the inkjet printing device 1, or it may be a device separate from the inkjet printing device 1.

[0015] The inkjet printing device 1 is a device for forming a drawing pattern on a workpiece W (an example of an object to be drawn on) that is transported by a conveyor (an example of a conveying device) 10, and is an in-line device used by being incorporated into a manufacturing line (also called a production line). The conveyor 10 is, for example, a belt conveyor, a roller conveyor, etc. The production line is made up of the conveyor 10. The production line is installed in various factories, warehouses, etc. The drawing machine 2 is fixed so that its relative position to the conveyor 10 is in a predetermined positional relationship.

[0016] During operation of the inkjet printing device 1, multiple workpieces W are placed on the transport surface 10a of the transporter 10 and transported sequentially in the direction of arrow A shown in Figure 1. Therefore, the upstream side in the transport direction is the left side of Figure 1, and the downstream side in the transport direction is the right side of Figure 1. The multiple workpieces W are placed on the transport surface 10a with spacing in the direction of arrow A, which is the transport direction. The direction perpendicular to arrow A and along the transport surface 10a is defined as the width direction.

[0017] Workpiece W is not particularly limited, but could include, for example, packaging materials for packing various products. A typical example of packaging material is cardboard. The inkjet printer 1 draws information on the workpiece W being transported by the conveyor 10, such as characters including numbers, symbols, barcodes, two-dimensional codes, images, marks, illustrations, or combinations thereof. When only characters are drawn, the inkjet printer 1 can be called a printing device, and the drawing device 2 can be called a printer. Furthermore, the drawing of information by the inkjet printer 1 also includes printing images, etc. In this case, the inkjet printer 1 can be called a printing device. In the following explanation, the term "drawing" will be used to include both printing and image printing.

[0018] Furthermore, the controller 4 is connected to an encoder 7 for detecting the position of the workpiece W, and a detection sensor 9, which will be described later. Based on the signals output from the encoder 7 and the detection sensor 9, the controller 4 detects the position of the workpiece W. The controller 4 controls the drawing machine 2 so that drawing begins when the workpiece W reaches a predetermined position.

[0019] (Configuration of drawing machine 2) The drawing machine 2 is a DOD (Drop On Demand) type drawing machine that ejects ink only when necessary for drawing operations. However, it may also be a CIJ (Continuous Ink Jet) type drawing machine that ejects ink even when not performing drawing operations. The following description will explain the case in which a DOD type drawing machine is used as drawing machine 2 in this embodiment.

[0020] As shown in Figure 2, the drawing machine 2 includes an ink supply unit 20, a print head drive unit 21, and a DOD print head (hereinafter referred to as the print head) 22. The drawing machine 2 also includes a main housing 25 (shown in Figure 1) on which the print head 22 is installed. The main housing 25 is fixed to a transporter 10, etc.

[0021] The print head 22 is fixed inside the main housing 25, and the positional relationship between the main housing 25 and the print head 22 is fixed. The ink supply unit 20 and the print head drive unit 21 are also housed inside the main housing 25.

[0022] The print head 22 of the DOD-type drawing machine 2 is a component corresponding to the ejection unit, and ejects ink supplied from the ink cartridge 20a toward the workpiece W transported by the transporter 10. A drawing pattern is formed on the workpiece W by the ink ejected from the print head 22. There are several types of print head structures, but any of them may be, for example, a thermal inkjet type, a valve jet type, or a piezo type. In this embodiment, a piezo type print head is used as the print head 22, which is capable of drawing from low resolution to high resolution, has a wide drawing width, and has high durability.

[0023] The print head 22 has multiple ejection ports (not shown) formed, for example, along the vertical direction. As shown in Figure 1, a vertically elongated opening 25a is formed on the surface of the main housing 25 facing the workpiece W. The surface of the print head 22 on which the ejection ports are formed is positioned to face outwards from the opening 25a of the main housing 25. Therefore, the ink ejected from the ejection ports of the print head 22 flies out of the main housing 25 through the opening 25a and adheres to the workpiece W.

[0024] The ink supply unit 20 is the part that supplies ink to the print head 22 and includes an ink cartridge 20a as an ink storage unit for storing ink. Instead of the ink cartridge 20a, an ink reservoir (ink storage unit) that can be refilled with ink may be provided.

[0025] The print head drive unit 21 is controlled by the control unit 40, which will be described later, when performing drawing operations. The print head drive unit 21 generates a drive electrical waveform for driving the print head 22 and outputs it to the print head 22. The drive electrical waveform is a waveform for individually driving the drive elements (piezo oscillators) provided at each ejection port of the print head 22 at timings based on the drawing command output from the control unit 40.

[0026] (Configuration of the inspection machine) Inspection machine 3 is a device that determines the quality of the drawing state of the drawing pattern drawn on the workpiece W based on the drawing data, using an image acquired by imaging the workpiece W, and corresponds to an image inspection unit. Inspection machine 3 can also be called an image inspection device. Inspection machine 3 is installed downstream of drawing machine 2, and is capable of inspecting the drawing state of the workpiece W drawn by drawing machine 2.

[0027] The inspection machine 3 comprises an illumination unit 30, an imaging unit 31, a control unit 32, and a storage unit 33. The illumination unit 30 is composed of, for example, light-emitting diodes, and is controlled by the control unit 32 to emit light at predetermined timings to illuminate the drawn portion of the workpiece W. The imaging unit 31 is a component for capturing images of the drawing pattern formed on the workpiece W and generating an image. This imaging unit 31 includes an optical system 31a that includes a lens that receives light irradiated from the illumination unit 30 and reflected from the surface of the workpiece W, an image sensor 31b that receives light emitted from the optical system 31a, and an AF motor 31c. The AF motor 31c is a component for automatically focusing on the drawn portion of the workpiece W by driving the focusing lens of the optical system 31a. The autofocus method is not particularly limited, and examples include a contrast method.

[0028] The image sensor 31b is composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) sensor. The image sensor 31b captures an image of the workpiece W to be drawn and generates an image. For example, the light intensity signal of the light-receiving element of the image sensor 31b is output to an FPGA (Field Programmable Gate Array) for processing (not shown in the diagram) and also output to a DSP (Digital Signal Processor) for processing.

[0029] The control unit 32 has an imaging setting unit 32a. The imaging setting unit 32a sets imaging setting parameters and reflects the set imaging setting parameters when imaging the workpiece W. The imaging setting parameters include multiple parameters such as the timing of illumination by the illumination unit 30, brightness (amount of light emitted), exposure time by the imaging unit 31, and focus (focal position) of the imaging unit 31. Although not shown, the GUI for setting imaging setting parameters has areas where the brightness of illumination, exposure time, focus, etc., can be set individually. When the user inputs each parameter on the GUI, the imaging setting unit 32a accepts the setting operation by the user and outputs each parameter to, for example, the storage unit 33 for storage. Each parameter can be read from the storage unit 33 as needed.

[0030] When acquiring image data of the workpiece W, the imaging setting unit 32a outputs imaging setting parameters to the illumination unit 30 and the imaging unit 31. The illumination unit 30 and the imaging unit 31 operate according to the imaging setting parameters. When the illumination unit 30 receives the imaging setting parameters, it sets them within the imaging unit 31 so that the received imaging setting parameters are reflected during imaging. Similarly, when the imaging unit 31 receives the imaging setting parameters, it sets them within the imaging unit 31 so that the received imaging setting parameters are reflected during imaging. When the illumination unit 30 and the imaging unit 31 receive an imaging trigger, they illuminate the workpiece W according to the imaging setting parameters and take images to acquire image data of the workpiece W.

[0031] The control unit 32 may be a part that performs rule-based image inspection as an inspection tool, a part that performs image inspection using a pre-trained model, or a part that performs both rule-based image inspection and image inspection using a pre-trained model. For example, the control unit 32 has the imaging unit 31 image the workpiece W, acquires the image data of the workpiece W, and performs inspection on the acquired image of the workpiece W based on the configured inspection tool. When performing inspection, the control unit 32 cuts out the area to be inspected from the image data. The control unit 32 extracts the feature quantities of the cut-out inspection area and uses a classifier to determine the extracted feature quantities. If the cut-out inspection area contains characters, the inspection machine 3 can perform character recognition processing, or so-called OCR, by using a dictionary when performing character recognition. In addition, if a barcode or two-dimensional code is drawn on the workpiece W, the inspection machine 3 can read the barcode or two-dimensional code.

[0032] The pass / fail determination unit 32b, located in the control unit 32 of the inspection machine 3, creates inspection results using an inspection tool and compares them with the inspection conditions. The inspection conditions are obtained from the drawing data generation unit 40b of the controller 4. The pass / fail determination unit 32b compares, for example, the result of character recognition processing by the control unit 32 with the correct character string obtained from the drawing data generation unit 40b. If they match, it determines the result to be good; otherwise, it determines the result to be bad. In the case of barcodes or two-dimensional codes, it compares the reading result of the control unit 32 with the code information obtained from the drawing data generation unit 40b. If they match, it determines the result to be good; otherwise, it determines the result to be bad.

[0033] For example, if there is only one configured inspection tool, the inspection results for that configured inspection tool are output as is. However, if multiple configured inspection tools are combined, further inspection results are generated based on the inspection results of each inspection tool and output from the pass / fail judgment unit 32b.

[0034] (Integrated fittings) As shown in Figure 1, the inkjet printer 1 is equipped with an integrated fitting 90 for fixing the inspection machine 3 to the main housing 25 that houses the print head 22. The integrated fitting 90 has a part to which the main housing 25 is attached and a part to which the inspection machine 3 is attached. The integrated fitting 90 has a predetermined dimension in the direction of transport of the workpiece W, and when the inspection machine 3 is fixed to the main housing 25 by the integrated fitting 90, the inspection machine 3 and the print head 22 can be positioned at a distance from each other in the direction of transport of the workpiece W, i.e., a fixed position relationship. By fixing the inspection machine 3 to the main housing 25 with the integrated fitting 90, the relative fixed position relationship with the print head 22 is defined.

[0035] The shape and structure of the integrated fitting 90 can be arbitrarily set. The length of the integrated fitting 90 can also be arbitrarily set. The integrated fitting 90 may be adjustable in length in the direction of transport of the workpiece W. The integrated fitting 90 may also be configured to allow changing the distance between the inspection machine 3 and the main housing 25.

[0036] The integrated fitting 90 is detachably attached to the main housing 25, for example by fastening members, and is also detachably attached to the inspection machine 3, for example by fastening members. As a result, the inspection machine 3 is detachably attached to the main housing 25.

[0037] There may be multiple types of integrated fittings 90. By preparing integrated fittings 90 with different dimensions in advance, the inspection machine 3 can be fixed to the main housing 25 using an integrated fitting 90 of the appropriate length according to the user's environment.

[0038] Figure 3 is a plan view showing an example of the installation of the drawing machine 2 and the inspection machine 3. When the workpiece W is being transported in the direction of arrow A, the inspection machine 3 can be installed downstream of the drawing machine 2 in the direction of workpiece W transport by providing the integrated fitting 90 as shown by the solid line. On the other hand, when the workpiece W is being transported in the direction of arrow B, opposite to the direction of arrow A, the inspection machine 3 can be installed downstream of the drawing machine 2 in the direction of workpiece W transport by providing the integrated fitting 90 as shown by the dashed line. In addition, by providing both the integrated fitting shown by the solid line and the integrated fitting 90 shown by the dashed line, it is possible to accommodate both the transport directions of arrow A and arrow B.

[0039] Figure 4 shows an example of the installation of the drawing machine 2 and the inspection machine 3, and is a view from the side from which the ink is ejected (front view). As shown in Figure 4, the inspection machine 3 is fixed to the main housing 25 by an integrated fitting 90 such that the vertical center of the drawing area and the vertical center of the field of view of the imaging unit 31 of the inspection machine 3 are at the same height.

[0040] (Detection sensor) As shown in Figure 1, the inkjet printing apparatus 1 is equipped with a detection sensor 9 that detects the arrival of a workpiece W being transported by a transporter 10. The detection sensor 9 is installed upstream of the drawing machine 2 in the transport direction of the workpiece W. The detection sensor 9 is equipped with, for example, an optical motion measuring sensor or a distance sensor (not shown), and these sensors enable the detection of the arrival of the transported workpiece W. When the detection sensor 9 detects the arrival of the workpiece W, it transmits a detection signal to the controller 4. Based on the detection signal output from the detection sensor 9, the controller 4 determines that the workpiece W has arrived at a predetermined position and, after a predetermined drawing delay time has elapsed, causes the drawing machine 2 to start drawing.

[0041] Furthermore, as will be described in detail later, in this embodiment, the detection signal output from the detection sensor 9 is also used to generate an imaging trigger for the imaging unit 31. Once it is determined that the workpiece W has arrived at a predetermined position, the imaging unit 31 is instructed to take an image after a predetermined imaging delay time has elapsed.

[0042] (Controller 4 configuration) As shown in Figure 2, the controller 4 comprises a control unit 40, a storage unit 41, and an operation display unit 42. The control unit 40 is composed of a microcomputer including, for example, a central processing unit and various memories, and is capable of executing pre-stored software. The control unit 40 is provided with a drawing setting unit 40a, a drawing data generation unit 40b, an inspection setting unit 40c, a display screen generation unit 40d, and a mode switching unit 40e. The drawing setting unit 40a, drawing data generation unit 40b, inspection setting unit 40c, display screen generation unit 40d, and mode switching unit 40e of the control unit 40 are parts composed of hardware and software, and for convenience they are described separately as the drawing setting unit 40a, drawing data generation unit 40b, inspection setting unit 40c, display screen generation unit 40d, and mode switching unit 40e, but they may be integrated in hardware.

[0043] The operation display unit 42 includes a controller-side display unit 42a, which is, for example, a liquid crystal display, and a controller-side operation unit 42b, which is, for example, an operation key. The controller-side operation unit 42b is the part that accepts various operations such as drawing content and settings. Various screens generated by the display screen generation unit 40d are displayed on the controller-side display unit 42a, so that the user can operate the controller-side operation unit 42b while looking at the controller-side display unit 42a. The operation status of the controller-side operation unit 42b can be acquired by the control unit 40.

[0044] The controller-side operation unit 42b may be a touch panel. The touch panel is a component capable of detecting operations performed by the user's finger. The type of touch panel is not particularly limited and examples include capacitive touch panels and infrared touch panels. User operation information on the touch panel is transmitted to the control unit 40.

[0045] The drawing setting unit 40a is the part that sets the drawing content to be drawn on the workpiece W to be drawn on. The drawing data generation unit 40b is the part that defines the ejection of ink from the print head 22 and generates drawing data corresponding to the drawing content set in the drawing setting unit 40a. The control unit 40 outputs a control signal to the print head drive unit 21 based on the drawing data generated by the drawing data generation unit 40b, and controls the ejection of ink from the ejection port of the print head 22.

[0046] The inspection setting unit 40c is the part that performs inspection settings by the inspection machine 3. The storage unit 41 is the part that stores the relative fixed position relationship between the inspection machine 3 and the print head 22. Based on the drawing content set by the drawing setting unit 40a and the relative fixed position relationship stored in the storage unit 41, the inspection setting unit 40c assists the user in setting inspection settings.

[0047] The details of the drawing and inspection settings will be explained below based on the flowchart in Figure 5. In step SA1 after the start of this flowchart, area information indicating the area on the workpiece W that can be imaged is stored in the storage unit 41. The area information is determined based on the field of view information that defines the imaging field of view of the imaging unit 31. The field of view information is information for determining the size of the image area used for image inspection. For example, when a part of the image acquired by the image sensor 31b is enlarged and cropped using digital zoom, and image inspection is performed on the cropped area, the information for determining the cropped area corresponds to the field of view information. In addition, the distance to the drawing pattern can be obtained based on the amount of operation of the AF motor 31c, and this distance information may be included in the field of view information.

[0048] The memory unit 41 can store region information determined based on the relative positional relationship of the imaging unit 31 with respect to the print head 22 and the field of view information. In this embodiment, an integrated fitting 90 is used to position the inspection machine 3 and the print head 22 at a fixed distance from each other in the transport direction of the workpiece W, so the relative positional relationship of the imaging unit 31 with respect to the print head 22 can be accurately determined.

[0049] In step SA2, the display screen generation unit 40d generates screen data for displaying the settings screen 100 as shown in Figure 6 and outputs it to the controller 4, causing the settings screen 100 to be displayed on the controller-side display unit 42a.

[0050] At the top of the settings screen 100 is a status display area 101 that displays the status of the inkjet printer 1. On the left side of the settings screen 100 is a screen switching area 102. The screen switching area 102 includes a home button 102a for displaying the home screen, a job button 102b for displaying the job editing screen, a settings button 102c for displaying the settings screen for various settings, and a logout button 102d for ending the drawing settings. Buttons 102a to 102d can be operated by the controller-side operation unit 42b. All subsequent operations on the screen can be operated by the controller-side operation unit 42b.

[0051] Figure 6 shows the state where the home button 102a is pressed, and therefore the home screen 110 is displayed in the area 103 to the right of the screen switching area 102 in the settings screen 100.

[0052] When a user operates the controller-side operation unit 42b and presses the job button 102b on the settings screen 100, the display screen generation unit 40d generates screen data to display the job editing screen 120 in area 103 of the settings screen 100, as shown in Figure 7, and displays it on the controller-side display unit 42a. On this job editing screen 120, the drawing setting unit 40a accepts the selection of the job to be edited from the user. That is, the lower part of the job editing screen 120 is provided with a job display area 121 where a list of jobs is displayed. In the state shown in Figure 7, the top job "000 SAMPLE 0" in the job display area 121 is selected. The upper part of the job editing screen 120 is provided with a drawing content display area 122. The drawing content display area 122 displays the drawing content of the job selected in the job display area 121. The drawing content display area 122 is provided with an edit button 122a.

[0053] When the display screen generation unit 40d detects that the edit button 122a has been operated by the user, a drawing element display area 123 is displayed in the lower part of the drawing content display area 122, as shown in Figure 8. The drawing elements are displayed in a list in the drawing element display area 123. In the example shown in Figure 8, there are five drawing elements: the date "00", the barcode "01", the two-dimensional code "02", the string "Expiration Date" "03", and the string "XYZ Company" "04", so five drawing elements are displayed in the drawing element display area 123.

[0054] As shown in Figure 8, a drawing setting button 123a and an inspection setting button 123b are provided on the left side of the drawing content display area 122. When the drawing setting button 123a is operated, the drawing setting is started, and the drawing setting screen is displayed on the setting screen 100. Specifically, as shown in Figure 9, an additional screen 124 is displayed in which blocks (also called drawing blocks) can be placed. A block indicates an area for placing elements, and elements are displayed within the block. The additional screen 124 is the part that displays the setting surface corresponding to the drawing area on the workpiece W that is drawn by ink ejected from the print head 22. In other words, the controller-side display unit 42a is a component for displaying the setting surface. The drawing setting unit 40a then places elements according to the drawing pattern on the setting surface displayed on the controller-side display unit 42a based on user operation.

[0055] Below the additional screen 124, a drawing element display area 123 is provided. Below the drawing element display area 123, edit buttons 124a, copy buttons 124b, paste buttons 124c, and delete buttons 124d for the added block are provided. The added block is indicated by a border 125 (see Figure 9). The added block can also be copied using the copy button 124b and pasted using the paste button 124c. Additionally, the added block can be deleted using the delete button 124d.

[0056] When the edit button 124a is operated while an added block exists, the display screen generation unit 40d generates screen data to display the block editing screen 126 in the area 103 of the settings screen 100, as shown in Figure 10, and displays it on the controller-side display unit 42a. The block editing screen 126 includes, for example, a formatting area 126a, a date setting area 126b, a character height (character size) setting area 126c, a character spacing setting area 126d, etc., if the block is a calendar.

[0057] When adjusting the position of a block, an adjustment screen 150, as shown in Figure 11, is displayed on the controller-side display unit 42a. The adjustment screen 150 includes a display area 151 where drawing elements are displayed and a position adjustment area 152. The drawing elements displayed in the display area 151 are linked to the inspection tool, and when the position of a drawing element is adjusted in the position adjustment area 152, that adjustment is reflected in the position adjustment of the region of interest in the inspection tool. In the position adjustment area 152, it is possible to, for example, operate an arrow indicating the direction of the position adjustment or input the amount of movement numerically. The position adjustment area 152 also includes a selection area 153 for selecting when adjusting the position of all blocks at once.

[0058] After arranging one or more blocks and adjusting their initial positions as described above, the process proceeds to step SA3 in Figure 5. In step SA3, the user performs the drawing content setting operation. When the user operates the complete button 126f shown in Figure 10, the drawing setting unit 40a determines the drawing content and temporarily saves it. In other words, based on the user operation, the drawing setting unit 40a places elements on the setting surface according to the drawing pattern, and then sets the drawing content composed of the placed elements.

[0059] Multiple elements can be placed on the configuration surface according to the drawing pattern. These elements can be arranged, for example, in the direction of transport by the conveyor 10, or in a direction perpendicular to the direction of transport by the conveyor 10.

[0060] In step SA4, the drawing setting unit 40a identifies the end of the drawing pattern in the transport direction by the transporter 10 based on the position of the elements placed on the setting surface. In this embodiment, the end of the drawing pattern in the transport direction is also called the "nearest point" as shown in Figure 12.

[0061] The end (nearest point) of the drawing pattern can be identified by the transport direction of the conveyor 10 and the drawing content. The transport direction of the conveyor 10 can be input by the user, for example, in the direction of arrow A or arrow B as shown in Figure 3. The drawing setting unit 40a acquires the transport direction of the conveyor 10 input by the user.

[0062] For example, let's explain the case where the drawing content shown in Figure 12 is set by the drawing setting unit 40a. In Figure 12, the transport direction by the transporter 10 is to the right, the transport direction by the transporter 10 is defined as the X direction, and the direction perpendicular to the transport direction is defined as the Y direction. The drawing pattern to be drawn on the workpiece W consists of a first block 201 containing the string "ABC" located on the upstream side of the transport direction, and a second block 202 containing the string "DEF" located on the downstream side. In this case, the drawing setting unit 40a identifies the upstream end of the second block 202 located on the upstream side of the transport direction as the nearest point 203. In this way, when multiple elements are included in a single drawing content, the drawing setting unit 40a identifies the upstream end of the element located at the uppermost position in the transport direction as the end of the drawing pattern. The upstream end of an element is the part where drawing is started by the print head 22.

[0063] Figure 13 shows an example of a display configuration by the controller-side display unit 42a. In the display configuration shown in Figure 13, the region 204 upstream of the nearest point 203 in the transport direction, as identified by the drawing setting unit 40a, is colored gray, while the region 205 downstream of the nearest point 203 in the transport direction is not colored gray. This makes it easy to identify the region 204 upstream of the nearest point 203, i.e., the region that is not the target of drawing. This display configuration is just one example; the two regions 204 and 205 can also be distinguished by changing the color of the region 204 upstream of the transport direction and the region 205 downstream of the transport direction, or by changing the type of hatching applied to both regions 204 and 205. In other words, the controller-side display unit 42a is configured to display the region 204 upstream of the edge of the drawing pattern and the region 205 downstream of the edge of the drawing pattern in different configurations.

[0064] In step SA5, the control unit 40 calculates the imaging delay time. The calculated imaging delay time can be stored, for example, in the memory unit 41. Figure 14 is a schematic diagram of a workpiece W being transported by the transporter 10, viewed from above. The transport direction is to the right, the imaging unit 31 is installed downstream of the transport direction, and the detection sensor 9 is installed upstream of the imaging unit 31 in the transport direction. Distance L1 is the distance from the upstream edge of the workpiece W in the transport direction to the nearest point 203, and can be obtained by going through steps SA3 and SA4 in Figure 5. Distance L2 is the distance between the detection sensor 9 and the center of the imaging field of view of the imaging unit 31, and is known. Distance L3 is the dimension of the imaging field of view of the imaging unit 31 (dimension along the transport direction), and can be obtained based on the field of view information. Time progresses in the order of times t1, t2, and t3.

[0065] Time t1 is the timing when the upstream edge of the workpiece W being transported by the conveyor 10 is detected by the detection sensor 9. Time t2 is the timing when the upstream edge of the workpiece W enters the imaging field of view of the imaging unit 31, but at time t2, the nearest point 203 is not yet in the imaging field of view of the imaging unit 31. At time t3, the nearest point 203 is in the upstream position of the imaging field of view of the imaging unit 31, and by issuing an imaging trigger at time t3, the imaging unit 31 can acquire the drawing content with the nearest point 203 as the edge of the field of view. In order to cause the imaging unit 31 to perform imaging so that the nearest point 203 enters the imaging field of view of the imaging unit 31, the control unit 40 acquires the calculation result of L1 + L2 + L3 / 2 and the detection timing of the workpiece W by the detection sensor 9, and calculates an imaging delay so as to issue an imaging trigger at the timing when the nearest point 203 enters the imaging field of view of the imaging unit 31. In other words, the control unit 40 determines the timing for issuing the imaging trigger based on the region information stored in the memory unit 41, the positions of the elements placed on the setting surface by the drawing setting unit 40a, and the detection timing of the detection sensor 9, and causes the imaging unit 31 to perform imaging. An example of an image captured by the imaging unit 31 at time t3 is shown in Figure 15. In this way, the control unit 40 determines the timing for issuing the imaging trigger so that all of the multiple elements are within the imaging field of view of the imaging unit 31.

[0066] For example, even if the drawing content differs for each workpiece W, such as the date or lot number, the positional relationship between the nearest point 203 and the imaging unit 31 remains unchanged, so all captured images will include the nearest point 203 at the edge of the field of view.

[0067] The control unit 40 determines the timing of issuing the imaging trigger so that the nearest point 203, which is the edge of the drawing pattern identified by the drawing setting unit 40a, is closer to the center of the imaging field of view of the imaging unit 31 than to the edge of the imaging field of view. In other words, because errors may occur in the detection timing of the workpiece W, the timing of issuing the imaging trigger is delayed so that the nearest point 203 is positioned slightly downstream from the edge of the field of view so that it does not overlap with the edge of the field of view. The timing of issuing the imaging trigger is set to accommodate this error in detection timing.

[0068] Figure 16 shows an input screen 140 for receiving input from the user of parameters related to distances L1 and L2. The input screen 140 is generated by the display screen generation unit 40d and displayed on the controller-side display unit 42a. The input screen 140 allows the user to select whether or not to link the imaging trigger with the drawing trigger. Specifically, the input screen 140 is provided with a linking button 140a to be operated when linking the imaging trigger with the drawing trigger, and a non-linking button 140b. When the linking button 140a is operated, the imaging trigger is linked with the drawing trigger, while when the non-linking button 140b is operated, the imaging unit 31 performs imaging using an externally input imaging trigger without linking the imaging trigger with the drawing trigger.

[0069] When the link button 140a is operated, the input screen 140 displays three areas: area 140c for inputting the distance L2a between the print head 22 and the detection sensor, area 140d for inputting distance L1, and area 140e for inputting the imaging position offset (L4). The user inputs the distances into areas 140c, 140d, and 140e, respectively. Based on these inputs, the control unit 40 can obtain the calculation result L1 + L2 + L3 / 2. Note that the screens for inputting each distance are not limited to the input screen 140, but can be any screen.

[0070] Identifying the nearest point 203 enables alignment between the drawing area and the corresponding setting surface, and a drawing trigger is issued so that the nearest point 203 of the element placed on the setting surface corresponding to the drawing area is drawn at a position separated from the edge of the work W by the distance L1 input to area 140d. In other words, distance L1 is the distance from the edge of the work W in the drawing area to the position where the nearest point 203 of the element placed on the setting surface corresponding to the drawing area is drawn.

[0071] Distance L2 is composed of distance L2a and distance L2b between the print head 22 and the imaging unit 31. In other words, since the detection sensor 9, print head 22, and imaging unit 31 are arranged in this order from upstream to downstream in the transport direction of the workpiece W, the first distance in the direction of alignment between the detection sensor 9 and the imaging unit 31 is the sum of the second distance in the direction of alignment between the detection sensor 9 and the print head 22 and the third distance in the direction of alignment between the print head 22 and the imaging unit 31. Since the distance L2b in the transport direction between the print head 22 and the imaging unit 31, whose relative positional relationship is defined by the fixing bracket 90, is stored in the storage unit 41, distance L2 can be calculated by adding it to distance L2a input to area 140c. If the setting is not configured to use the fixing bracket 90, the relative positional relationship between the print head 22 and the imaging unit 31 may differ from the relative positional relationship stored in the memory unit 41. Therefore, an area for the user to input the distance L2b is displayed on the input screen 140, similar to other parameters.

[0072] The distance L3 is determined based on the field of view information of the imaging unit 31 and the fixed positional relationship between the print head 22 and the imaging unit 31, and is included in the area information stored in the storage unit 41. Specifically, the distance L3 is determined as the distance between the two ends of the area on the workpiece W where the drawing pattern can be captured, in the direction in which the print head 22 and the imaging unit 31 are aligned. The determined value of distance L3 is stored in the storage unit 41.

[0073] The position offset L4 is a parameter that allows the user to adjust the distance between the nearest point 203 and the edge of the imaging field of view of the imaging unit 31. For example, if the area of ​​the entire drawing pattern that occupies a small portion of the imaging field of view is small, offsetting the nearest point 203 and the edge of the imaging field of view of the imaging unit 31 allows for the acquisition of an image in which the drawing pattern is positioned in the central part of the imaging field of view.

[0074] Distances L1 and L2a are parameters that are also referenced when calculating the delay time of the drawing trigger. In other words, the control unit 40 issues a drawing trigger when the workpiece W has moved from upstream to downstream in the transport direction by the sum of distances L1 and L2a, after the detection sensor 9 has detected the edge of the workpiece W. In other words, some of the parameters that make up distances L1, L2, L3, and L4, which are necessary to calculate the imaging delay time of the imaging trigger, are common to distances L1 and L2a, which are necessary to calculate the drawing delay time of the drawing trigger. That is, since the imaging trigger is linked to the drawing trigger, positional misalignment of the captured image relative to the drawing pattern formed on the workpiece W is less likely to occur, and user input of settings is also easier. For example, even if the distances L1 and L2a entered by the user in areas 140c and 140d are incorrect, the drawing timing and imaging timing will not be relatively misaligned because the parameters referenced when calculating the printing delay time and imaging delay time are the same.

[0075] Once distances L1, L2, L3, and L4 are determined, the time can be calculated by obtaining speed information as the workpiece W is transported. The user can choose whether to obtain the speed information assuming that the workpiece W is moving at a constant speed or by using the encoder 7. Figure 18 shows the input screen 141 when the workpiece W is moving at a constant speed. Figure 19 shows the input screen 141 when the encoder 7 is used. The input screen 141 is provided with a speed information selection area 141a and a speed input area 141b. In the speed information selection area 141a, the user can select and input either "constant speed" or "encoder". If "constant speed" is selected, the transport speed can be entered in the speed input area 141b. The control unit 40 calculates the time using the transport speed entered in the speed input area 141b and the distances L1, L2, L3, and L4. On the other hand, if "Encoder" is selected, the input screen 141 shown in Figure 19 displays a resolution input area 141c for inputting the encoder resolution and a pulse input area 141d for inputting the encoder pulse. The control unit 40 calculates the time using the distances L1, L2, and L3, the signal output from the encoder, the resolution input to the resolution input area 141c, and the pulse input to the pulse input area 141d.

[0076] Figure 17 shows the input screen 140 when the non-linking button 140b is operated. When the non-linking button 140b is operated, an area 140c for inputting distance L2a, an area 140d for inputting distance L1, and an area 140f for inputting imaging delay time are displayed. In area 140f, the delay time from the external input can be input as the imaging delay time. After receiving input from the detection sensor 9, if it is determined that the time entered in area 140f has elapsed, an imaging trigger is issued. In other words, distances L2a and L1 are used to determine the timing of issuing the drawing trigger, but they are not used to calculate the timing of issuing the imaging trigger. That is, the imaging trigger and the drawing trigger are not linked.

[0077] In step SA6 shown in Figure 5, the inspection settings are started. For example, when the user operates the inspection setting button 123b shown in Figure 8, the inspection settings are started, and the inspection settings screen is displayed on the settings screen 100 as shown in Figure 20. The settings screen 100 shown in Figure 20 is provided with a master image display area 160 and an inspection tool display area 161 in which inspection tools are listed. The master image display area 160 displays the master image of the workpiece W acquired by the imaging unit 31 of the inspection machine 3.

[0078] On the left side of the settings screen 100 are a master registration button 160a, a tool setting button 160b, a test run button 160c, and an inspection setting save button 160d. When the master registration button 160a is operated, the imaging unit 31 images the workpiece W and acquires a master image, which is displayed in the master image display area 160. When acquiring a master image, the imaging unit 31 can generate a master image by imaging the drawing pattern formed on the workpiece W by the ink ejected from the print head 22.

[0079] The master image displayed in the master image display area 160 can be configured to select a master image from previously acquired images based on user operation, or it can be configured to allow the user to choose whether to select a master image from previously acquired images or for the imaging unit 31 to image the workpiece W and acquire a master image. When selecting a master image from previously acquired images, after step SA5 in Figure 5, the imaging unit 31 can be controlled to image the drawing pattern formed on the object to be drawn by the ink ejected from the ejection unit during test printing, and the acquired image can be displayed as the master image in the master image display area 160.

[0080] When the tool setting button 160b is operated, the inspection tool display area 161 displays information about the inspection tool. In this example, the master image display area 160 displays the region of interest 100a for the text inspection tool, the region of interest 100b for the barcode inspection tool, and the region of interest 100c for the two-dimensional code inspection tool. The inspection operation can be tested by operating the test run button 160c.

[0081] By configuring the inspection settings, the blocks and inspection tools are linked. Subsequently, when the user operates the inspection settings save button 160d, the linked blocks and inspection tools are saved in the storage unit 41 or similar.

[0082] Next, the operation of the inkjet printing device 1 will be explained based on the flowchart shown in Figure 21. In step SB1, the control unit 40 acquires the imaging delay time stored in the memory unit 41, etc. During operation, multiple workpieces W are sequentially transported by the transporter 10, so the detection sensor 9 will detect the arrival of the workpieces W at a certain timing (step SB2).

[0083] In step SB3, the control unit 40 issues a trigger. Figure 22 is a timing chart of the detection sensor 9, the drawing machine 2, and the inspection machine 3. When the detection sensor 9 detects the arrival of the workpiece W, it outputs a detection signal. When the control unit 40 receives the signal from the detection sensor 9, it adds a predetermined drawing delay time and outputs a drawing start trigger to the drawing data generation unit 40b. Upon receiving the drawing start trigger, the drawing data generation unit 40b generates drawing data and outputs it to the drawing machine 2. The drawing machine 2, having received the drawing data, performs the drawing. In this way, the print head 22 ejects ink to the workpiece W at a timing based on the detection timing of the detection sensor 9.

[0084] The control unit 40 outputs an imaging trigger to the imaging unit 31 so that the inspection machine 3 performs inspection of the drawing pattern after the drawing machine 2 has performed drawing. Specifically, upon receiving a signal from the detection sensor 9, the control unit 40 outputs an imaging trigger to the imaging unit 31, adding the imaging delay time acquired in step SB1. In this way, the control unit 40 can determine the timing of issuing the imaging trigger based on the timing when the print head 22 ejects ink onto the workpiece W. As a result, as shown at time t3 in Figure 14, an image can be acquired for inspection in which the nearest point 203 is included at the edge of the field of view, enabling accurate inspection.

[0085] In this embodiment, there are two modes for capturing a drawing pattern: a first mode in which the imaging unit 31 captures a drawing pattern at a timing based on region information stored in the storage unit 41, the positions of elements placed on the setting surface by the drawing setting unit 40a, and the detection timing of the detection sensor 9; and a second mode in which the imaging unit 31 captures a drawing pattern at a timing based on a delay time or delay distance relative to the detection timing of the detection sensor 9 set by the user, and the detection timing of the detection sensor 9. Switching between the first and second modes is performed by a mode switching unit 40e (shown in Figure 2). For example, if the user selects the first mode, the mode switching unit 40e causes the imaging unit 31 to perform imaging in the first mode, while if the user selects the second mode, the mode switching unit 40e causes the imaging unit 31 to perform imaging in the second mode.

[0086] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]

[0087] As explained above, this disclosure can be used, for example, when drawing various information on packaging materials such as cardboard boxes. [Explanation of Symbols]

[0088] 1. Inkjet printing device 2 drawing machine 3. Inspection machine (image inspection unit) 9 detection sensors 20a Ink cartridge (ink reservoir) 24 Print head (ejector) 31 Imaging Unit 40 Control Unit 40a Drawing settings section 40e Mode switching section 41 Storage section

Claims

1. An ink reservoir that holds the ink, A discharge unit that discharges ink supplied from the ink storage unit toward an object to be drawn on, which is transported by a transport device, An imaging unit captures a drawing pattern formed on an object to be drawn by the ink ejected from the aforementioned ejection unit and generates an image of the captured image. An image inspection unit performs image inspection of the drawing pattern using the captured image generated by the imaging unit, A storage unit that stores region information indicating an area on the object to be drawn that can capture a drawing pattern, which is determined based on the field of view information defining the imaging field of the imaging unit, A display unit that displays a setting surface corresponding to the drawing area on the object to be drawn, which is drawn by the ink ejected from the ejection unit, A setting unit that, based on user operation, places elements according to a drawing pattern on the setting surface displayed on the display unit and sets the drawing content, A detection sensor for detecting the arrival of an object to be drawn, which is transported by the transport device, An inkjet printing apparatus comprising: a control unit that determines the timing of issuing an imaging trigger based on the area information stored in the storage unit, the position of the element placed on the setting surface by the setting unit, and the detection timing of the detection sensor.

2. In the inkjet printing apparatus according to claim 1, The control unit, Furthermore, the inkjet printing apparatus determines the issuance timing of the imaging trigger based on the first relative positional relationship between the detection sensor and the imaging unit in the direction of alignment.

3. In the inkjet printing apparatus according to claim 1, The control unit, The setting unit determines the timing of issuing a drawing trigger based on the position of the element placed on the setting surface, the second relative positional relationship between the detection sensor and the discharge unit in the alignment direction, and the detection timing of the detection sensor. An inkjet printing apparatus that determines the issuance timing of the imaging trigger based on the second relative positional relationship between the detection sensor and the ejection unit in the direction of alignment, and the third relative positional relationship between the ejection unit and the imaging unit in the direction of alignment.

4. In the inkjet printing apparatus according to claim 3, The system further includes an input unit for inputting the second relative positional relationship, The memory unit is an inkjet printing device that stores the third relative positional relationship.

5. In the inkjet printing apparatus according to claim 1, An inkjet printing apparatus in which the storage unit stores the area information determined based on the relative positional relationship of the imaging unit with respect to the ejection unit and the field of view information.

6. In the inkjet printing apparatus according to claim 1, The ejection unit ejects ink onto the object to be drawn at a timing based on the detection timing of the detection sensor. An inkjet printer wherein the control unit determines the timing of issuing an imaging trigger based on the area information stored in the storage unit, the position of the element placed on the setting surface by the setting unit, and the timing at which the ejection unit ejects ink to the object to be drawn.

7. In the inkjet printing apparatus according to claim 1, The setting unit identifies the end of the drawing pattern in the transport direction by the transport device based on the position of the element placed on the setting surface. The control unit determines the timing for issuing an imaging trigger based on the positional relationship between the edge of the region indicated by the region information and the edge of the drawing pattern identified by the setting unit, and the detection timing of the detection sensor, in an inkjet printing apparatus.

8. In the inkjet printing apparatus according to claim 1, A first mode in which the imaging unit captures a drawing pattern at a timing based on the region information stored in the memory unit, the position of the element placed on the setting surface by the setting unit, and the detection timing of the detection sensor, A second mode in which the imaging unit captures a drawing pattern at a timing based on a delay time or delay distance relative to the detection timing of the detection sensor set by the user, and the detection timing of the detection sensor, An inkjet printer equipped with a mode switching unit that allows switching between modes.

9. In the inkjet printing apparatus according to claim 1, The imaging unit is an inkjet printing apparatus that captures a drawing pattern formed on an object to be drawn by ink ejected from the ejection unit and generates a master image.

10. In the inkjet printing apparatus according to claim 7, The setting unit, based on user operation, arranges a plurality of elements according to the drawing pattern on the setting surface displayed on the display unit. The control unit determines the timing of issuing an imaging trigger so that all of the multiple elements are within the imaging field of view of the imaging unit, in an inkjet printing apparatus.

11. In the inkjet printing apparatus according to claim 7, The setting unit, based on user operation, arranges a plurality of elements on the setting surface displayed on the display unit according to the drawing pattern, and identifies the end of the element located at the uppermost position in the transport direction by the transport device as the end of the drawing pattern.

12. In the inkjet printing apparatus according to claim 7, The display unit displays different patterns in the region upstream of the end of the drawing pattern identified by the setting unit in the transport direction by the transport device, and in the region downstream of the end of the drawing pattern identified by the setting unit in the transport direction by the transport device.

13. In the inkjet printing apparatus according to claim 7, The control unit determines the timing of issuing an imaging trigger so that the end of the drawing pattern identified by the setting unit is closer to the center of the imaging field of view of the imaging unit than the end of the imaging field of view of the imaging unit.

Images