Character detection device and method for inkjet printer
By designing a character detection device for the inkjet printer, the orientation of the inkjet printing surface on the card is automatically detected and adjusted, solving the problem of card rejection caused by incorrect placement of the inkjet printing surface, and improving production efficiency and detection accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI SECURITY PRINTING
- Filing Date
- 2026-04-21
- Publication Date
- 2026-06-30
AI Technical Summary
During the card coding process, some qualified cards are rejected due to incorrect placement of the coding surface, requiring manual secondary sorting, which wastes manpower and reduces production efficiency.
Design a character detection device for an inkjet printer, including a first detection device, a suction device, an inkjet printer, a second detection device, and a rejection mechanism. By detecting the orientation of the inkjet printing surface of the card, the inkjet printing and detection process is automatically adjusted. A reference area is set to improve detection accuracy, and the character area is separated for image and content detection.
It eliminates the need for secondary sorting by manual labor, improving production efficiency, reducing manpower waste, and enhancing testing accuracy and finished product quality.
Smart Images
Figure CN122298701A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of printing technology, specifically to a character detection device and method for an inkjet printer. Background Technology
[0002] Currently, in the card coding and inspection process, after the cards are fed onto the conveyor belt by the card issuing machine, the coding operation begins once the marking points on the cards are detected. After coding is completed, a vision inspection device checks whether the coding is qualified; cards that fail are rejected. In this process, the marking points on the card are set on the side to be coded. Therefore, when the side of the card not to be coded is facing up, the coding equipment does not operate and will not coded. After passing through the vision inspection device, the card is marked as unqualified and rejected.
[0003] However, this method has problems. Some cards are of acceptable quality, but they are rejected because the coding surface is placed incorrectly. This requires manual secondary sorting, which wastes manpower and reduces production efficiency. Summary of the Invention
[0004] To overcome the shortcomings of the prior art, the present invention provides a character detection device and method for an inkjet printer.
[0005] To achieve the above objectives, a character detection device for an inkjet printer is designed, comprising a worktable. Along the conveying direction of a first conveyor belt, the worktable is equipped with a first detection device, a suction device, an inkjet printer, a second detection device, a rejection mechanism, and a second conveyor belt. The first detection device includes a support frame, a horizontal moving module, a lifting module, and a detection camera. The upper end of the worktable is connected to the support frame, and the upper end of the support frame is equipped with the horizontal moving module. The lifting module is connected to the horizontal moving module via a connecting block, and the lower end of the lifting module is connected to the detection camera. The suction device includes a rotating base, a connecting frame, a lifting cylinder, a fixed plate, and a suction cup. The upper end of the worktable is connected to the rotating base, and the upper end of the rotating base is connected to the connecting frame. The connecting frame is connected to the lifting cylinder, and the lower end of the lifting cylinder is connected to the fixed plate. The lower end of the fixed plate is equipped with a suction cup.
[0006] The inkjet printer is equipped with a photoelectric sensor on one side.
[0007] The structure of the second detection device is the same as that of the first detection device.
[0008] Both the first and second detection devices are equipped with display screens on one side.
[0009] The conveyor belt is equipped with a light source on one side, and the position of the light source is matched with the position of the first detection device or the second detection device.
[0010] The waste removal mechanism includes a movable plate, a lifting cylinder, and a collection drawer. The front end of the movable plate is located on the left and right sides of the end of the first conveyor belt. The rear end of the movable plate is connected to the left and right sides of the second conveyor belt via a rotating shaft. The lower ends of the left and right sides of the movable plate are respectively provided with lifting cylinders. The lower side of the end of the first conveyor belt is provided with a collection drawer.
[0011] The width of the movable plate is greater than the width of the left and right sides of the conveyor belt.
[0012] Counters are installed between the suction device and the inkjet printer, and on one side of the waste rejection mechanism.
[0013] To achieve the above objectives, a method for designing a character detection device for an inkjet printer is provided, comprising the following steps: S1, place the material to be processed at the first end of the conveyor belt. When the material passes the first detection device, the detection camera of the first detection device takes a picture and detects whether the side of the material to be printed is facing up. S2, if the side to be printed is facing up, the suction device does not move and enters the bottom of the printing equipment. If the side to be printed is facing down, the lifting cylinder of the suction device drives the fixing plate downward and picks up the material through the suction cup. After picking up the material, the rotating base rotates 90° and releases the picked-up material onto the worktable and resets. S3, below the material coding equipment, the photoelectric sensor detects the marking points on the material and then performs coding; S4, After the inkjet printing is completed, it enters the second detection device for character recognition; S5, if the character recognition is qualified, the material enters the second conveyor belt through the surface of the movable plate. If the character recognition is unqualified, the lifting cylinder lifts the left and right sides of the movable plate, the material enters the collection drawer, and the lifting cylinder resets.
[0014] In step S4, the character recognition method is as follows: S41, Template Management, includes: S411: Collect a standard qualified inkjet-printed product image as a template base image, and select a stable and unchanging feature area as the reference area. S412, set the positioning range, starting angle, and angle range of the reference area, enable relative position offset measurement, and set the allowable X / Y offset; S413, Select the character inspection area, and set the allowable range of edge distortion, allowable range of grayscale value variation, and allowable range of defect size; S414, Select the character recognition area, set the number of characters and the minimum width and height of a single character; S42, Image Acquisition, including: S421, The detection camera of the second detection device collects real-time images of the material after inkjet printing; S422: Call the reference area of the template base map, and perform a matching search between the acquired image and the template base map. Matching is performed according to the set starting angle and angle range. If the matching degree is higher than the threshold, the positioning is considered successful. If the positioning fails multiple times in a row, it is marked as poor positioning. S423, after successful positioning, the reference area is used as a marker to correct the positional deviation caused by real-time image offset and rotation, and lock the character detection area; S43, Defect detection in the character inspection area, including: S431, perform a second matching between the locked area and the template base map; S432 compares the grayscale of the real-time image with the template image and calculates the brightness change ratio, edge distortion, and grayscale difference. S433, identify the size of the defect point and determine whether it exceeds the allowable size range of the defect point; S434, determine whether there are defects such as missing print, missing print, ink spots, dirt, misalignment, or broken lines; S44, Content detection of the character recognition area, including: S441 performs binarization segmentation on the character region to separate the character from the background; S442 filters interference points according to the set number of characters and minimum width and height, calls the character library for matching and recognition, and determines whether there are duplicate codes, wrong codes, or missing codes. S45, Result Judgment: Any of the following situations will be judged as defective and trigger the subsequent rejection mechanism: location failure, defect exceeding the threshold, character cannot be recognized, content mismatch, duplicate code, missing code.
[0015] Compared with the prior art, the present invention has the following advantages: 1. By adding a first detection device and a suction device, cards with incorrectly placed coding surfaces can be detected and removed before coding, eliminating the need for manual secondary sorting. They only need to be placed back into the card issuing machine during material feeding, saving manpower and improving production efficiency.
[0016] 2. For character detection, a reference area is set up, and the angle of the real-time image is adjusted according to the reference area to improve detection accuracy.
[0017] 3. Character region detection is divided into image detection and character content detection to improve the quality of the final product. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of the present invention.
[0019] Figure 2 This is a schematic diagram of the structure of the first detection device and the suction device of the present invention.
[0020] Figure 3This is a schematic diagram of the waste removal mechanism of the present invention. Detailed Implementation
[0021] The present invention will now be further described with reference to the accompanying drawings.
[0022] like Figures 1 to 3 As shown, the workbench 3 is equipped with a first detection device 4, a suction device 5, a coding device 6, a second detection device 7, a rejection mechanism 8, and a second conveyor belt 2 along the conveying direction of the first conveyor belt 1. The first detection device 4 includes a support frame 4-1, a horizontal moving module 4-2, a lifting module 4-3, and a detection camera 4-4. The upper end of the workbench 3 is connected to the support frame 4-1, and the upper end of the support frame 4-1 is equipped with the horizontal moving module 4-2. The horizontal moving module 4-2 is connected to the connecting block 4-5. The lifting module 4-3 is connected to the lifting module 4-3, and the lower end of the lifting module 4-3 is connected to the detection camera 4-4. The suction device 5 includes a rotating base 5-1, a connecting frame 5-2, a lifting cylinder 5-3, a fixing plate 5-4, and a suction cup 5-5. The upper end of the worktable 3 is connected to the rotating base 5-1, the upper end of the rotating base 5-1 is connected to the connecting frame 5-2, the lifting cylinder 5-3 is connected to the connecting frame 5-2, the lower end of the lifting cylinder 5-3 is connected to the fixing plate 5-4, and the lower end of the fixing plate 5-4 is provided with a suction cup 5-5.
[0023] A photoelectric sensor 9 is installed on one side of the inkjet printer 6. The photoelectric sensor 9 works in conjunction with the marking dots on the marking surface of the card. When a marking dot is detected, the inkjet printer 6 performs inkjet printing.
[0024] The structure of the second detection device is the same as that of the first detection device 4.
[0025] Both the first detection device 4 and the second detection device 7 are equipped with a display screen 10 on one side.
[0026] A light source 11 is provided on one side of the conveyor belt 1, and the position of the light source 11 is matched with the position of the first detection device 4 or the second detection device 7. In this embodiment, two light sources are provided to illuminate the detection cameras of the first detection device 4 and the second detection device 7, respectively.
[0027] The waste removal mechanism 8 includes a movable plate 8-1, a lifting cylinder 8-2, and a collection drawer 8-3. The front end of the movable plate 8-1 is provided on the left and right sides of the end of the conveyor belt 1. The rear end of the movable plate 8-1 is connected to the left and right sides of the conveyor belt 2 via a rotating shaft. The lower end of the left and right sides of the movable plate 8-1 is provided with a lifting cylinder 8-2. The lower side of the end of the conveyor belt 1 is provided with a collection drawer 8-3.
[0028] The width of the movable plate 8-1 is greater than the width of the left and right sides of the conveyor belt 1. The lifting cylinder 8-2 lifts the plate from the extra width to prevent interference with the falling cards.
[0029] Counters 12 are installed between the suction device 5 and the inkjet printer 6, and on one side of the waste rejection mechanism 8.
[0030] The method for character detection of the above-mentioned inkjet printer includes the following steps: S1, the material to be processed is placed at the beginning of the conveyor belt 1. When the material passes through the first detection device 4, the detection camera 4-4 of the first detection device 4 takes a picture and detects whether the side of the material to be printed is facing up. S2, if the side to be printed is facing up, the suction device 5 does not move and enters below the printing device 6. If the side to be printed is facing down, the lifting cylinder 5-3 of the suction device 5 drives the fixing plate 5-4 downward, and the material is picked up by the suction cup 5-5. After picking up, the rotating base 5-1 rotates 90° to release the picked-up material onto the worktable 3 and resets. S3, below the material coding device 6, the photoelectric sensor 9 detects the marking points on the material and then performs coding; S4, After the inkjet printing is completed, it enters the second detection device 7 for character recognition; S5, if the character recognition is qualified, the material enters the conveyor belt 2 through the surface of the movable plate 8-1. If the character recognition is unqualified, the lifting cylinder 8-2 lifts the left and right sides of the movable plate 8-1, and the material enters the collection drawer 8-3 under the action of gravity. The lifting cylinder 8-2 then resets.
[0031] In step S4, the character recognition method is as follows: S41, Template Management, includes: S411: Collect a standard qualified inkjet-printed product image as the template base image, and select stable and unchanging feature areas as the reference area, such as fixed logo and border. S412, set the positioning range, starting angle, and angle range of the reference area, enable relative position offset measurement, and set the allowable X / Y offset; S413, Select the character inspection area, and set the allowable range of edge distortion, allowable range of grayscale value variation, and allowable range of defect size; S414, Select the character recognition area, set the number of characters and the minimum width and height of a single character; S42, Image Acquisition, including: S421, The detection camera of the second detection device collects real-time images of the material after inkjet printing; S422: Call the reference area of the template base map, and perform a matching search between the acquired image and the template base map. Matching is performed according to the set starting angle and angle range. If the matching degree is higher than the threshold, the positioning is considered successful. If the positioning fails multiple times in a row, it is marked as poor positioning. S423, after successful positioning, the reference area is used as a marker to correct the positional deviation caused by real-time image offset and rotation, and lock the character detection area; S43, Defect detection in the character inspection area, including: S431 performs a secondary matching between the locked area and the template base map to improve detection accuracy; S432 compares the grayscale of the real-time image with the template image and calculates the brightness change ratio, edge distortion, and grayscale difference. S433, identify the size of the defect point and determine whether it exceeds the allowable size range of the defect point; S434, determine whether there are defects such as missing print, missing print, ink spots, dirt, misalignment, or broken lines; S44, Content detection of the character recognition area, including: S441 performs binarization segmentation on the character region to separate the character from the background; S442 filters interference points according to the set number of characters and minimum width and height, calls the character library for matching and recognition, and determines whether there are duplicate codes, wrong codes, or missing codes. S45, Result Judgment: Any of the following situations will be judged as defective and trigger the subsequent rejection mechanism: location failure, defect exceeding the threshold, character cannot be recognized, content mismatch, duplicate code, missing code.
[0032] In step S4, the character inspection area detects the image of the character region, and the character recognition area detects the character content.
Claims
1. A character detection device for an inkjet printer, comprising a worktable, characterized in that: The workbench (3) is equipped with a first detection device (4), a suction device (5), a coding device (6), a second detection device (7), a rejection mechanism (8), and a second conveyor belt (2) along the conveying direction of the first conveyor belt (1). The first detection device (4) includes a support frame (4-1), a horizontal moving module (4-2), a lifting module (4-3), and a detection camera (4-4). The upper end of the workbench (3) is connected to the support frame (4-1), and the upper end of the support frame (4-1) is equipped with a horizontal moving module (4-2). The horizontal moving module (4-2) is connected to a connecting block (4-5). The lifting module (4-3) is connected, and the lower end of the lifting module (4-3) is connected to the detection camera (4-4). The suction device (5) includes a rotating base (5-1), a connecting frame (5-2), a lifting cylinder (5-3), a fixing plate (5-4), and a suction cup (5-5). The upper end of the worktable (3) is connected to the rotating base (5-1), the upper end of the rotating base (5-1) is connected to the connecting frame (5-2), the lifting cylinder (5-3) is connected to the connecting frame (5-2), the lower end of the lifting cylinder (5-3) is connected to the fixing plate (5-4), and the lower end of the fixing plate (5-4) is provided with a suction cup (5-5).
2. The character detection device for an inkjet printer according to claim 1, characterized in that: The inkjet printer (6) is equipped with a photoelectric sensor (9) on one side.
3. The character detection device for an inkjet printer according to claim 1, characterized in that: The structure of the second detection device is the same as that of the first detection device (4).
4. A character detection device for an inkjet printer according to claim 1 or 3, characterized in that: The first detection device (4) and the second detection device (7) are each equipped with a display screen (10) on one side.
5. The character detection device for an inkjet printer according to claim 1, characterized in that: The conveyor belt (1) is provided with a light source (11) on one side, and the position of the light source (11) is matched with the position of the first detection device (4) or the second detection device (7).
6. The character detection device for an inkjet printer according to claim 1, characterized in that: The waste removal mechanism (8) includes a movable plate (8-1), a lifting cylinder (8-2), and a collection drawer (8-3). The front end of the movable plate (8-1) is provided on the left and right sides of the end of the first conveyor belt (1). The rear end of the movable plate (8-1) is connected to the left and right sides of the second conveyor belt (2) through a rotating shaft. The lower end of the left and right sides of the movable plate (8-1) is provided with a lifting cylinder (8-2). The lower side of the end of the first conveyor belt (1) is provided with a collection drawer (8-3).
7. The character detection device for an inkjet printer according to claim 7, characterized in that: The width of the movable plate (8-1) is greater than the width of the left and right sides of the conveyor belt (1).
8. The character detection device for an inkjet printer according to claim 1, characterized in that: Counters (12) are provided between the suction device (5) and the inkjet printer (6) and on one side of the waste removal mechanism (8).
9. A method for character detection device of inkjet printer according to any one of claims 1-8, characterized in that: Includes the following steps: S1, place the material to be processed at the beginning of the conveyor belt (1). When the material passes through the first detection device (4), the detection camera (4-4) of the first detection device (4) takes a picture and detects whether the side of the material to be printed is facing up. S2, if the side to be printed is facing up, the suction device (5) does not move and enters below the printing device (6). If the side to be printed is facing down, the lifting cylinder (5-3) of the suction device (5) drives the fixing plate (5-4) downward and picks up the material through the suction cup (5-5). After picking up the material, the rotating base (5-1) rotates 90° and releases the picked-up material onto the worktable (3) and resets. S3, below the material coding equipment (6), the photoelectric sensor (9) detects the marking points on the material and then performs coding; S4, After the inkjet printing is completed, it enters the second detection device (7) for character recognition; S5, if the character recognition is qualified, it enters the second conveyor belt (2) through the surface of the movable plate (8-1). If the character recognition is unqualified, the lifting cylinder (8-2) lifts the left and right sides of the movable plate (8-1), and the material (under the action of gravity) enters the collection drawer (8-3). The lifting cylinder (8-2) resets.
10. A method for character detection device of inkjet printer according to claim 9, characterized in that: In step S4, the character recognition method is as follows: S41, Template Management, includes: S411: Collect a standard qualified inkjet-printed product image as a template base image, and select a stable and unchanging feature area as the reference area. S412, set the positioning range, starting angle, and angle range of the reference area, enable relative position offset measurement, and set the allowable X / Y offset; S413, Select the character inspection area, and set the allowable range of edge distortion, allowable range of grayscale value variation, and allowable range of defect size; S414, Select the character recognition area, set the number of characters and the minimum width and height of a single character; S42, Image Acquisition, including: S421, The detection camera of the second detection device collects real-time images of the material after inkjet printing; S422: Call the reference area of the template base map, and perform a matching search between the acquired image and the template base map. Matching is performed according to the set starting angle and angle range. If the matching degree is higher than the threshold, the positioning is considered successful. If the positioning fails multiple times in a row, it is marked as poor positioning. S423, after successful positioning, the reference area is used as a marker to correct the positional deviation caused by real-time image offset and rotation, and lock the character detection area; S43, Defect detection in the character inspection area, including: S431, perform a second matching between the locked area and the template base map; S432 compares the grayscale of the real-time image with the template image and calculates the brightness change ratio, edge distortion, and grayscale difference. S433, identify the size of the defect point and determine whether it exceeds the allowable size range of the defect point; S434, determine whether there are defects such as missing print, missing print, ink spots, dirt, misalignment, or broken lines; S44, Content detection of the character recognition area, including: S441 performs binarization segmentation on the character region to separate the character from the background; S442 filters interference points according to the set number of characters and minimum width and height, calls the character library for matching and recognition, and determines whether there are duplicate codes, wrong codes, or missing codes. S45, Result Judgment: Any of the following situations will be judged as defective and trigger the subsequent rejection mechanism: location failure, defect exceeding the threshold, character cannot be recognized, content mismatch, duplicate code, missing code.