Multi-nozzle round bottle printer control method and system

Abstract

The invention discloses a control method and system of a multi-nozzle round bottle printer. The method comprises the following steps that S1, a picture to be printed is imported into the system; s2, scanning the shape and the position of the bottle through a height measurement module and an algorithm; s3, according to the picture in the step S1, the ink jet drop point position on the bottle is calculated through an algorithm; s4, converting the inkjet drop point position calculated in the step S2 into printing data, and transmitting the printing data to a round bottle printer; s5, the position of the bottle is confirmed again, and printing is started after no error exists; the defects of an existing round bottle printer in the bottle shape detection link are overcome, the shape of the bottle is accurately calculated through the height measurement module, the ink jet drop point position on the bottle is calculated through software, and the purpose of accurate printing is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of printers, and in particular to a control method and system for a multi-nozzle round bottle printer. Background Art

[0002] In today's packaging and printing industry, as the market's requirements for product personalization, diversification and environmental protection continue to increase, round bottle printers are gradually emerging as an innovative printing solution. It has many significant advantages. For example, in terms of printing efficiency, compared with traditional printing and dyeing methods, it does not require cumbersome plate-making processes and can directly perform digital printing operations, which greatly shortens the time interval from design to finished product and can quickly respond to market demand; in terms of proofing costs, it avoids the high initial investment in plate-making in traditional processes, making small-batch production proofing more economical and affordable; the printing effect is even more remarkable. With advanced nozzle technology and precise ink jet control mechanism, it can achieve high-resolution, colorful and fine-patterned printing effects, meeting the strict requirements of mid-to-high-end products for appearance quality; and from an environmental protection perspective, it mostly uses environmentally friendly inks, and generates less pollutants during the printing process, which is in line with the current concept of green development. It is precisely because of these advantages that the round bottle printer has mainly served proofing and small-batch production from the beginning. With the continuous improvement and maturity of its own process equipment, it has now developed into a mature technology that can be applied to large-scale production, and has been increasingly widely used in the market, gradually forming a trend of replacing the high-energy-consuming and high-pollution traditional printing and dyeing industry.

[0003] However, despite the many advantages of the round bottle printer, it still has certain shortcomings in detecting the shape of bottles in practical applications.

[0004] In the workflow of round bottle printers, accurate detection of bottle shape is one of the key prerequisites to ensure high-quality printing.

[0005] At present, most round bottle printers mainly use the following conventional methods in the bottle shape detection link:

[0006] The first is a positioning detection method based on a mechanical fixture. By designing a specific mechanical fixture to fix the round bottle, the shape, outline and size range of the bottle can be roughly determined by the contact between the fixture and the bottle surface. Although this method is simple and direct, it has obvious limitations. Mechanical fixtures can often only adapt to a limited number of bottles of standard sizes and shapes. For bottles with irregular shapes, special curved surfaces or non-standard sizes, it is difficult to achieve precise fitting and positioning, which can easily cause the bottle to shake or shift during the printing process, thereby affecting the accuracy of printing and causing quality problems such as misalignment and deformation of the pattern.

[0007] The second method is to use a simple photoelectric sensor for shape detection. The photoelectric sensor obtains partial shape information of the bottle by detecting the reflection and occlusion of light on the bottle surface. However, this method can only obtain relatively rough shape features. It is difficult to accurately identify complex shapes such as subtle bumps and curves on the bottle surface. It cannot provide sufficiently accurate bottle shape data for subsequent printing operations such as nozzle height adjustment and printing path planning, which will ultimately affect the perfect presentation of the printed pattern on the bottle surface.

[0008] The third is to use the partial application of the visual inspection system. Some round bottle printers are equipped with visual inspection systems, but most of these systems are relatively simple in function and only perform some basic contour recognition. When faced with bottle surfaces with complex textures, strong reflections, or colors close to the background, the visual algorithm is prone to misjudgment and cannot accurately distinguish the true shape details of the bottle. For example, it is impossible to accurately identify the local concave or convex parts on the bottle, so that the print head cannot accurately adjust the height and optimize the path according to the actual shape, reducing the printing quality.

[0009] In summary, the existing round bottle printers are not perfect in terms of bottle shape detection technology, and it is difficult to meet the needs of increasingly diverse round bottle product shapes and high-precision printing. Summary of the invention

[0010] In order to solve the above-mentioned technical problems, the present invention provides a control method and system for a multi-nozzle round bottle printer.

[0011] The technical solution of the present invention is achieved in this way:

[0012] A control method for a multi-nozzle round bottle printer comprises the following steps:

[0013] S1, import the picture to be printed into the system;

[0014] S2, through the height measurement module, the algorithm scans the shape and position of the bottle;

[0015] S3, according to the picture in step S1, the inkjet landing point position on the bottle is calculated by an algorithm;

[0016] S4, converting the inkjet landing point position calculated in step S2 into printing data and transmitting it to the round bottle printer;

[0017] S5, confirm the bottle position again, and start printing after it is correct.

[0018] Preferably, in step S1, the user imports the image file to be printed into the image processing software connected to the computer. The image processing software parses and converts the input image data according to preset printing parameters, converts it into a printing data format suitable for the round bottle printer, and transmits it to the control system of the round bottle printer.

[0019] Preferably, in step S2, the height measuring module is specifically an infrared sensor, which obtains the height and shape of the bottle through the reflected infrared light.

[0020] Preferably, the step S3 further includes the following sub-steps:

[0021] S31, based on the bottle shape and position information obtained in step S2, the software fits the imported image onto the three-dimensional surface model of the bottle according to a mapping rule;

[0022] S32, the software will correspond each pixel point in the image to the actual physical position on the bottle surface according to the actual shape of the bottle and the position of the bottle in the printer coordinate system, and establish a one-to-one correspondence between the two-dimensional image pixel coordinates and the three-dimensional surface coordinates of the bottle;

[0023] S33, according to the physical characteristics of the nozzle and the printing mode of the printer (such as spiral printing, partition printing or line-by-line scanning printing, etc.), the software further determines the specific landing point position corresponding to each pixel point on the bottle surface when it is actually converted into an inkjet operation through an inkjet landing point calculation algorithm and an established coordinate correspondence relationship.

[0024] Preferably, in step S4, the data processing module in the printer control system reads the inkjet landing point position information data list generated in step S3, and then performs encoding conversion according to a data format that can be recognized and processed by the printer hardware.

[0025] Preferably, the step S5 specifically includes: pre-printing detection, the height measurement module works twice, quickly re-detects the shape and position of the bottle, obtains the latest bottle position information, and compares it with the initial position information previously stored in the system memory. If the comparison result shows that the position deviation of the bottle in the X, Y, and Z axis directions is within a very small error threshold range, it is considered that the bottle position is still accurate and no adjustment is required, and the printing stage can be directly entered; however, if a large deviation in the bottle position is detected, the system will automatically issue an alarm prompt message to inform the user that the bottle position has changed and the bottle placement position needs to be readjusted.

[0026] A control system for a multi-nozzle round bottle printer, comprising a communication module, a data processing module, a signal processing module and a nozzle control module;

[0027] The communication module is responsible for establishing information interaction between the various components of the printer and with external devices; the data processing module is responsible for comprehensive processing of various types of data received to ensure that they meet the execution requirements of various components of the printer; the signal processing module is responsible for collecting, converting and processing various physical signals involved in the operation of the printer; the nozzle control module, each nozzle corresponds to a nozzle control board, and each nozzle control board receives a unified inkjet synchronization signal and its corresponding print data subset.

[0028] Preferably, the communication module has designed protocols in layers and categories for different communication objects and data types. When interacting with a computer, a high-level protocol based on the TCP / IP protocol framework is adopted. On the basis of ensuring network communication compatibility, functions are added to adapt to the large data transmission and real-time control requirements of the printer.

[0029] Preferably, the nozzle control module also includes a nozzle status monitoring function, which monitors the working status of each nozzle in real time by setting current detection and temperature detection sensors in the nozzle circuit.

[0030] The present invention solves the shortcomings of the current round bottle printer in the bottle shape detection link. Through the height measurement module, the shape of the bottle is accurately calculated, and the inkjet landing point position on the bottle is calculated through software to achieve the purpose of precise printing. The present invention can be adapted to round bottles of various shapes and sizes. Whether it is a conventional cylindrical bottle or a bottle with a certain taper or special curved surface, corresponding coordinate conversion and landing point calculation can be performed according to its specific situation to ensure that round bottles of different shapes can achieve high-quality printing and meet the printing needs of diversified product packaging, decoration, etc. The operation of the present invention is simple and easy to understand, workers can quickly get started, and training costs are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of a control method of a multi-nozzle round bottle printer of the present invention.

[0032] Figure 2 It is a schematic diagram of a control system of a multi-nozzle round bottle printer of the present invention. DETAILED DESCRIPTION

[0033] In order to further explain the technical means and effects taken by the present invention to achieve the predetermined invention purpose, exemplary embodiments will be described in detail here, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are only examples of methods and systems consistent with some aspects of the present application as detailed in the attached claims.

[0034] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0035] Example 1

[0036] like Figure 1 and Figure 2 As shown, a control method of a multi-nozzle round bottle printer of the present invention comprises the following steps:

[0037] S1, import the picture to be printed into the system;

[0038] Preferably, in step S1, the user imports the image file to be printed into the image processing software connected to the computer, and the image processing software analyzes and converts the input image data according to the preset printing parameters, converts it into a printing data format suitable for the round bottle printer, and transmits it to the control system of the round bottle printer;

[0039] The user first opens the image processing software specially designed for use on the computer terminal connected to the multi-nozzle round bottle printer. The software has a user-friendly interface design and is easy to operate, making it easy for users to perform various image-related operations. Users can find the image files to be printed in the local storage device (hard disk, USB flash drive, etc.) through a conventional file browsing window (such as the file manager in common operating systems). The image file formats that can be imported are wide, covering common formats such as JPEG, PNG, TIFF, etc., to meet the needs of different users to obtain image materials from various design software.

[0040] After selecting the image file, the user clicks the "Import" button (or similar function button) on the software interface to successfully load the image file into the image processing software. At this time, the software will automatically parse the basic attribute information of the image file, including the image size (width and height expressed in pixels), color mode (such as common RGB, CMYK, etc.) and original resolution (pixels per inch, dpi), etc., and display it to the user in the corresponding area of ​​the software interface, so that the user can confirm whether the initial state of the image meets expectations.

[0041] S2, through the height measurement module, the algorithm scans the shape and position of the bottle;

[0042] Preferably, in step S2, the height measuring module is specifically an infrared sensor, which obtains the height and shape of the bottle through the reflected infrared light;

[0043] More preferably, in the height measurement module, the infrared sensor uses the time taken by the light to be refracted and returned as the basis for distance measurement. Assume that the distance from the infrared sensor to the fixture is fixed at L, and the different distances from the infrared sensor to the bottle are expressed as L1, L2, L3....Ln. In the set of L1, L2, L3....Ln, it is mapped to the coordinate system of the printer system to form a shape formed by connecting multiple points, and this shape is the measured shape of the bottle.

[0044] More preferably, in the height measurement module, during the process of detecting the shape of the bottle, on the one hand, the bottle is set as a regular cylinder, and only any side of the bottle needs to be detected. By obtaining the side detection result, the complete bottle shape can be obtained by rotating 360° or 180°; on the other hand, the bottle is set to an irregular shape, and the bottle is divided into the front and the back with the fixture as a reference, the front of the bottle is detected first, and then the side of the bottle is detected, and the complete irregular-shaped bottle is obtained by combining the front and side detection results.

[0045] The height measurement module specifically uses an infrared sensor to detect the shape and position of the bottle. It consists of an infrared transmitting unit, an infrared receiving unit, and a corresponding signal processing circuit. It is installed in the printer at a key position related to the bottle placement and printing area, which can fully cover the spatial range of the bottle and ensure accurate acquisition of the relevant geometric information of the bottle. The infrared transmitting unit will emit infrared light of a specific frequency and intensity to the area where the bottle is located. These infrared lights will be reflected when they encounter the surface of the bottle, and some of the lights will return to the infrared receiving unit along the original path. After receiving the returned infrared light, the infrared receiving unit will convert the optical signal into an electrical signal and pass it to the signal processing circuit. The signal processing circuit analyzes and processes information such as the propagation time and intensity change of the light to obtain the height and shape-related data of the bottle. For example, based on the time difference of the infrared light's round trip and the speed of light propagation in the air, the distance information from the infrared emission point to each point on the bottle surface can be calculated; through the collaborative work of multiple infrared sensors at different angles and positions, a large number of distance data points are collected, and then these data points are integrated and analyzed using geometric algorithms to build a three-dimensional contour model of the bottle surface, and then determine the shape of the bottle, such as whether it is a cylinder, a cone, or an irregular shape with a special curved surface, as well as its position in the printer coordinate system. In actual operation, in order to improve the accuracy and stability of the measurement, the height measurement module will perform multiple infrared light emission and reception operations and collect multiple sets of data samples. Then, these raw data samples are pre-processed, including removing abnormal data points caused by factors such as ambient light interference and sensor noise (for example, by setting a reasonable distance threshold, data points that are obviously beyond the normal measurement range are eliminated), and filtering the valid data (digital filtering methods such as mean filtering and median filtering can be used to smooth the data curve and reduce fluctuations) to enhance the reliability of the data. The valid data after preprocessing will serve as the basis for subsequent algorithm processing, which is used to accurately scan the shape of the bottle and the exact position information of the bottle, and store this information in the memory of the printer control system, providing a key basis for subsequent printing operations.

[0046] S3, according to the picture in step S1, the inkjet landing point position on the bottle is calculated by an algorithm;

[0047] Preferably, the step S3 further includes the following sub-steps:

[0048] S31, based on the bottle shape and position information obtained in step S2, the software fits the imported image onto the three-dimensional surface model of the bottle according to a mapping rule;

[0049] After the software obtains the bottle shape and position information determined in step S2, the image fitting operation is started. First, the appropriate mapping method is selected according to the geometric shape characteristics of the bottle. For example, for a cylindrical bottle, a cylindrical coordinate system is established based on the axis of the bottle, and the bottle surface is unfolded as a rectangular plane. The imported image is mapped to this unfolded plane according to a certain proportional relationship and coordinate mapping rules; for bottles with cones or more complex shapes, more complex surface unfolding and coordinate transformation algorithms are used to achieve preliminary fitting of the image and the bottle surface.

[0050] During this process, the software will consider the position information of the bottle and perform translation, rotation and other adjustments to the image to ensure that the image can accurately correspond to the surface position of the bottle actually placed in the printer. For example, if the bottle has a certain amount of translation in the horizontal direction relative to the origin of the printer's coordinate system, the software will perform translation correction on the coordinate mapping of the image in the horizontal direction accordingly; if the bottle has a rotation angle around a certain coordinate axis, the software will use the corresponding rotation matrix transformation to adjust the angle of the image to match the actual posture of the bottle, and finally achieve a rough fit between the image and the bottle surface in three-dimensional space, laying the foundation for subsequent precise coordinate correspondence.

[0051] S32, the software will correspond each pixel point in the image to the actual physical position on the bottle surface according to the actual shape of the bottle and the position of the bottle in the printer coordinate system, and establish a one-to-one correspondence between the two-dimensional image pixel coordinates and the three-dimensional surface coordinates of the bottle;

[0052] Based on the above-mentioned image matching, the software further performs fine coordinate correspondence operations. For each point on the bottle surface, according to the actual shape of the bottle and its position in the printer coordinate system, each pixel in the image is accurately matched to the actual physical position on the bottle surface, establishing a strict one-to-one correspondence.

[0053] For bottles of different shapes, the specific corresponding methods are different. Taking a cylindrical bottle as an example, after fitting the image to the unfolded rectangular plane on the bottle surface, define the angle coordinates along the circumferential direction of the bottle, and define the height coordinates along the axial direction of the bottle. For any pixel point in the image, its horizontal pixel coordinates (assuming that the width direction of the image is the x pixel coordinate) are mapped to the circumferential angle coordinates of the unfolded rectangular plane on the bottle surface according to a certain proportional relationship, and the vertical pixel coordinates are mapped to the height coordinates of the unfolded rectangular plane on the bottle surface according to the corresponding proportion. Then, through the conversion relationship between the cylindrical coordinate system and the three-dimensional Cartesian coordinate system, the image pixel coordinates are converted to the actual three-dimensional surface coordinates of the bottle. For bottles of other complex shapes, based on their specific surface geometric relationships and coordinate transformation rules, the precise correspondence of each pixel point to the three-dimensional coordinates of the bottle surface is achieved through calculation, so that each pixel point can find a unique corresponding physical position on the bottle surface, providing an accurate coordinate basis for accurately calculating the inkjet landing position;

[0054] S33, according to the physical characteristics of the nozzle and the printing mode of the printer, the software uses a special inkjet drop point calculation algorithm and the established coordinate correspondence to further determine the specific drop point position of each pixel point on the bottle surface when it is actually converted into an inkjet operation. According to the physical characteristics of the nozzle and the printing mode of the printer, the software uses a special inkjet drop point calculation algorithm and the established coordinate correspondence to further determine the specific drop point position of each pixel point on the bottle surface when it is actually converted into an inkjet operation.

[0055] Regarding the arrangement of the nozzles, if the nozzles are arranged in a straight line and are evenly spaced along the axial direction of the bottle, and the nozzle spacing is d, the software will determine the axial area of ​​the bottle that each nozzle is responsible for based on the nozzle serial number and spacing (the calculation method is as described above, and can be adjusted by considering factors such as the expansion of the upper and lower coverage range caused by the nozzle injection angle), and then determine which nozzle is responsible for the axial area corresponding to each pixel point; if the nozzles are arranged in a circle (commonly used for all-round printing on the circumferential surface of the bottle), the software will determine the distribution angle interval of the nozzles on the circumference and the radius distance r0 of the nozzle relative to the axis of the bottle. These parameters are used to clarify the starting and ending angle range of each nozzle in the circumferential direction of the bottle, so as to determine which nozzle is responsible for the circumferential direction corresponding to each pixel point.

[0056] Learn in detail about the distribution of nozzle holes of a single nozzle. The nozzle holes are usually arranged in a regular array on the surface of the nozzle. Assume that the spacing of the nozzle holes in the horizontal direction of the nozzle is Δx1, and the spacing in the longitudinal direction is Δy1. At the same time, determine the numbering rule of each nozzle hole (for example, numbering in rows or columns starting from the upper left corner). When calculating the inkjet landing point, find the nozzle hole that is most suitable for ejecting the ink drop corresponding to the pixel according to the position of the pixel to be printed and the distribution characteristics of the nozzle holes. For example, for the coordinate position (x1, y1) of a certain pixel after mapping on the bottle surface (here are the coordinates after the previous bottle surface mapping, which have corresponded to the actual position on the bottle surface), by comparing the coordinates with the nozzle hole spacing and numbering relationship (a simple coordinate range judgment or a more complex distance optimization algorithm can be used to select the nozzle hole closest to the pixel point and meet the conditions such as the injection angle), determine which nozzle hole is responsible for ejecting the ink droplet.

[0057] At the same time, considering the effect of nozzle spacing on printing continuity, especially when multiple nozzles work together, the spraying areas of adjacent nozzles need to have a certain overlap to ensure that the printed pattern will not have faults or uneven colors at the junction of the nozzles. Determine the appropriate nozzle overlap ratio through experiments or theoretical calculations (generally around 10%-30%, adjusted according to nozzle performance and printing quality requirements), and when calculating the inkjet drop position, adjust the effective spray range of the nozzle and the division of labor and cooperation between adjacent nozzles according to the overlap requirements to ensure that the inkjet coverage of the entire bottle surface is uniform and continuous. Through this series of complex and sophisticated calculation processes, the specific drop position corresponding to each pixel on the bottle surface when it is converted into an inkjet operation is finally determined, and a detailed data list containing all inkjet drop position information is generated and stored in the system memory for backup, ready for subsequent print data conversion and transmission.

[0058] S4, converting the inkjet landing point position calculated in step S2 into printing data and transmitting it to the round bottle printer;

[0059] S5, confirm the bottle position again, and start printing after it is correct.

[0060] Preferably, the step S5 specifically includes: pre-printing detection, the height measurement module works twice, quickly re-detects the shape and position of the bottle, obtains the latest bottle position information, and compares it with the initial position information previously stored in the system memory. If the comparison result shows that the position deviation of the bottle in the X, Y, and Z axis directions is within a very small error threshold range, it is considered that the bottle position is still accurate and no adjustment is required, and the printing stage can be directly entered; however, if a large deviation in the bottle position is detected, the system will automatically issue an alarm prompt message to inform the user that the bottle position has changed and the bottle placement position needs to be readjusted.

[0061] Preferably, in step S4, the data processing module in the printer control system reads the inkjet landing point position information data list generated in step S3, and then performs encoding conversion according to a data format that can be recognized and processed by the printer hardware.

[0062] Preferably, in step S3, the inkjet landing point calculation method is as follows:

[0063] First, determine the specific arrangement layout of the nozzles on the printer. Common arrangements include linear arrangement, circular arrangement, or matrix arrangement.

[0064] For example, in the case of linear arrangement, the nozzles are evenly spaced along the axial direction of the bottle. Let the nozzle spacing be d. When calculating the inkjet landing point, the axial area of ​​the bottle that each nozzle is responsible for is determined based on the nozzle serial number and spacing. Assuming that there are n nozzles in total and the bottle height is H, the axial height range that the i-th nozzle is responsible for can be roughly determined to be from (i-1)*d to i*d.

[0065] For the nozzles arranged in a circle, it is necessary to determine the distribution angle interval of the nozzles on the circumference, set as θ0. For example, if there are m nozzles evenly distributed on the circumference, then θ0 = 360 / m degrees, and the radius distance r of the nozzle relative to the axis of the bottle. Through these parameters, the starting and ending angle range of each nozzle in the circumferential direction of the bottle can be clearly determined, providing a basis for the subsequent calculation of the specific nozzle and landing point position corresponding to each pixel point.

[0066] Assume that the spacing of the nozzles in the horizontal direction of the nozzle is Δx1, and the spacing in the vertical direction is Δy1, and determine the numbering rule of each nozzle. When calculating the inkjet point, find the nozzle that sprays the ink drop corresponding to the pixel according to the position of the pixel to be printed and the distribution characteristics of the nozzles. For example, for the coordinate position (x1, y1) of a certain pixel after mapping on the bottle surface, by comparing the coordinates with the nozzle spacing and numbering relationship, determine which nozzle is responsible for spraying the ink drop. This may involve simple coordinate range judgment or more complex distance optimization algorithm.

[0067] Consider the effect of nozzle spacing on printing continuity, especially when multiple nozzles work together, the spraying areas of adjacent nozzles need to have a certain overlap to ensure that the printed pattern will not have faults or uneven colors at the junction of the nozzles. Determine the appropriate nozzle overlap ratio through experiments or theoretical calculations (generally around 10%-30%, adjusted according to nozzle performance and printing quality requirements), and when calculating the inkjet drop position, adjust the effective spray range of the nozzle and the division of labor and cooperation between adjacent nozzles according to the overlap requirements to ensure that the inkjet coverage of the entire bottle surface is uniform and continuous.

[0068] Spiral Printing:

[0069] In the spiral printing mode, the nozzle moves along the spiral trajectory on the bottle surface and sprays ink. When calculating the inkjet landing point, it is necessary to determine the position of the nozzle at each moment and the corresponding inkjet point based on the parametric equation of the spiral. The basic parameters of the spiral include the pitch (the axial distance between adjacent spirals, set as p), the radius (the radius of the nozzle rotating around the axis of the bottle, generally equal to the bottle radius plus the appropriate distance from the nozzle to the bottle surface, set as R) and the starting angle (the initial angle of the nozzle on the circumference of the bottle when it starts printing, set as θ1).

[0070] For a given time t (which can be determined based on the nozzle movement speed and printing progress), the nozzle's angular coordinate θ(t) in the circumferential direction of the bottle can be calculated by the formula θ(t) = θ1 + (2π*v1*t / (2πR)) (where v1 is the nozzle's movement speed in the circumferential direction), and the height coordinate h(t) in the axial direction can be calculated by h(t) = v2*t (v2 is the nozzle's movement speed in the axial direction). Combined with the correspondence between the pixel coordinates obtained by the previous bottle surface mapping and the bottle surface coordinates, the actual position of the pixel point to be printed on the bottle surface at each time t is determined, and then the appropriate nozzle orifice and the corresponding inkjet landing point are found, so that the ink droplets can be accurately sprayed on the corresponding position of the bottle surface where the spiral trajectory passes, achieving a spiral continuous printing effect.

[0071] Partition printing:

[0072] The bottle surface is divided into several different areas (for example, according to the height and circumferential angle range of the bottle, the bottle can be equally divided into several intervals in the axial direction and several angle intervals in the circumferential direction to form a sub-area grid), and each area is printed by a specific nozzle or nozzle combination.

[0073] For each sub-area, according to its boundary range and the pixel points to be printed in the area, the specific nozzles and inkjet drop point positions corresponding to each pixel point in the area are determined according to the arrangement of the nozzles and the nozzle hole distribution rules. For example, the angle range of a sub-area in the circumferential direction of the bottle is from θ2 to θ3, and the axial height range is from h1 to h2. Combined with the circumferential and axial distribution of the nozzles, the nozzles covering the area are found, and the corresponding drop point positions are calculated for each pixel point in the area to ensure smooth printing connection between each sub-area and complete and unified printing patterns on the entire bottle surface.

[0074] Progressive Scan Printing:

[0075] The nozzle scans and sprays ink line by line along the axial direction of the bottle, similar to the application of the line-by-line printing method of a flat printer on the surface of the bottle. First determine the starting and ending positions of each line (determined according to the circumference of the bottle and the coverage of the nozzle). For each line, calculate the inkjet drop position corresponding to each pixel on the line according to the nozzle distribution and spacing of the nozzle. For example, starting from the bottom of the bottle, the height coordinate of the first line is h3 (usually a reference height at the bottom of the bottle), and the nozzle scans from the starting angle θ4 to the ending angle θ5 along the circumferential direction (determined according to the nozzle coverage angle and the circumference of the bottle). In this process, according to the angular coordinate position of each pixel on the line and the nozzle distribution, determine which nozzle sprays the ink droplet at what position, and complete the printing of the entire bottle surface line by line in sequence to ensure the printing continuity and pattern integrity between each line.

[0076] A control system for a multi-nozzle round bottle printer, comprising a communication module, a data processing module, a signal processing module and a nozzle control module;

[0077] The communication module is responsible for information exchange between various components of the printer and with external devices.

[0078] It uses a variety of communication methods and interfaces to ensure that data between different modules in the system can be transmitted accurately and efficiently. On the physical level, the mainboard and the computer are connected through optical fiber cables to form a local area network environment, ensuring long-distance, high-speed and stable data transmission, and meeting the interactive needs of large amounts of image data and control instructions during the printing process. At the same time, inside the printer, the mainboard and the carriage board and expansion board are connected through a specially designed high-speed data bus, and the nozzle control board and the mainboard also have independent communication lines. Each connection line uses a wiring method with strong anti-interference ability to reduce the impact of external electromagnetic interference on communication and ensure communication quality;

[0079] In order to achieve efficient and reliable communication between various boards, the communication module has designed protocols in layers and categories for different communication objects and data types. When interacting with computers, a high-level protocol based on the TCP / IP protocol framework is used. On the basis of ensuring network communication compatibility, functions that adapt to the large data transmission and real-time control requirements of printers are added. For example, the print task identification field in the data packet header is added to facilitate the motherboard to quickly identify and classify the received data as image data, control instructions, or status query requests. For communication between various boards inside the printer, a lightweight, message-oriented custom protocol is used. The protocol specifies the format of the message in detail, including the message start identifier, message length, message type, specific data content, and checksum. Through this rigorous message format definition, each board can accurately parse and encapsulate the received and sent messages, avoid misreading and erroneous parsing during data transmission, and ensure the accuracy of communication.

[0080] Establish communication between the computer and the mainboard. The computer serves as the initiator of the printing task and sends the pictures to be printed, the set printing parameters and other data prepared by the user to the mainboard through the communication module. The communication module first encapsulates these data on the computer side according to the above-mentioned custom protocol, converts them into network data packets, and then sends them to the corresponding network interface of the mainboard through the optical fiber network cable. After receiving the data packet, the communication module of the mainboard will perform strict verification and unpacking operations to verify the integrity and correctness of the data packet. If the verification passes, the data in it will be extracted and passed to the data processing module for subsequent processing; if an error is found in the data packet, a retransmission request will be sent to the computer until the correct data is received. At the same time, the mainboard can also feedback the real-time status information of the printer to the computer through the communication link, so that users can understand the working status of the printer in real time;

[0081] Establish communication between the main board and the carriage board and expansion board. During the printing process, the main board needs to transmit printing data to the carriage board, such as image data fragments corresponding to each nozzle divided according to the nozzle layout, and motion control instructions. This information will be packaged into messages according to the internal custom protocol and sent to the corresponding carriage board through the high-speed data bus. After receiving the message, the carriage board will parse it, perform corresponding operations according to the instructions, and feed back the position signal, working status and other information collected by itself to the main board, which will also be sent in the specified message format to achieve two-way information interaction and ensure the accurate positioning and motion coordination of the nozzle during the printing process;

[0082] Establish communication between the printhead control boards. The printhead control board mainly receives key information such as inkjet control instructions and synchronization signals from the main board. Its communication interface can monitor the messages sent by the main board in real time. Once it receives instructions related to itself, it will immediately parse and execute the corresponding inkjet control operations. For example, according to the inkjet timing, ink drop size, jet frequency, and corresponding color channel information specified in the instructions, the printhead can be accurately controlled to spray ink. At the same time, the working status of the printhead can also be fed back to the main board, so that corresponding maintenance measures can be taken in time to ensure the normal printing work;

[0083] The signal processing module is responsible for comprehensively processing all types of received data to ensure that they meet the execution requirements of various components of the printer.

[0084] When the communication module sends the data from the computer or other boards to the data processing module, it first performs a data legitimacy check and preprocessing operation. For image data, it verifies whether its format meets the standards supported by the printer. If the format does not meet the standards, it attempts to convert the format or prompts the user to prepare a suitable image file again. At the same time, it checks the resolution, color mode and other parameters of the image data. If the resolution is too high and may exceed the physical printing capacity of the printer, it will perform appropriate downsampling to optimize the data volume. If the color mode is inconsistent with the color configuration of the nozzle, the color conversion algorithm is called to convert it to a color mode that is suitable for the nozzle.

[0085] After completing the preprocessing, for the printed image data, the data processing module will segment and distribute the image data according to the number of nozzles of the printer and the physical layout of the nozzles. If the printer of the present invention has at least 16 nozzles, the entire image will be evenly divided into 16 areas in the circumferential direction, and the image data corresponding to each area will be distributed to the corresponding nozzle control board to ensure that each nozzle is responsible for printing a part of the image, and the parts can be seamlessly connected to form a complete print pattern. During the distribution process, the image data will be further converted into a format that can be directly recognized by the nozzle, and the color information of the image will be decomposed and encoded according to the color channel of the nozzle. At the same time, combined with parameters such as the resolution and physical spacing of the nozzle, the detailed information such as the nozzle inkjet position and inkjet amount corresponding to each pixel point is determined, and an exclusive print data subset for each nozzle is generated to fully prepare for the subsequent precise inkjet printing;

[0086] In order to cope with the needs of temporary storage and efficient call of large amounts of data in complex printing tasks, the data processing module is equipped with a complete data caching mechanism.

[0087] A special data cache area is opened in the memory, and classified storage is performed according to data type and processing stage, which is convenient for quick retrieval and use. For example, when receiving a large image file from a computer, the data will be temporarily stored in the cache area first, and pre-processed while receiving to avoid untimely processing or data loss due to excessive data volume; during the printing process, the print data subsets of each nozzle that have been processed but not yet sent to the nozzle control board will also be stored in the cache area in an orderly manner, and the corresponding data will be pushed in time according to the printing progress of the nozzle to ensure the continuity of printing. At the same time, data cache management also involves operations such as data update and clearing. When a printing task is completed, the relevant cache data is cleaned up in time to release memory space to prepare for the data processing requirements of the next printing task, ensuring the efficiency and stability of the entire data processing process.

[0088] The signal processing module is responsible for collecting, converting and processing various physical signals involved in the operation of the printer, and providing accurate real-time feedback information and key control basis for the control system.

[0089] Various types of sensors are installed at key positions of the printer to collect different signals. For example, a grating sensor is installed on the track where the nozzle moves. Through the cooperation of the grating scale and the photoelectric detection element, the position information of the nozzle in the X, Y, and Z axis directions can be accurately detected. The principle is to use the grating stripes on the grating scale to block and transmit light, produce periodic light signal changes, and the photoelectric detection element converts the light signal into an electrical signal to obtain the displacement information of the nozzle; flow sensors are set at the ink pump and ink pipeline to monitor the flow of ink and convert the changes in physical pressure or flow rate caused by the flow of ink into electrical signal output; the printer is also equipped with a temperature sensor to detect the temperature changes of key components such as nozzles and motors in real time, and also feedback the temperature value in the form of electrical signals. The original electrical signals collected by these sensors are usually analog signals. The analog-to-digital conversion circuit in the signal processing module will perform analog-to-digital conversion on them and convert the analog signals into digital signals for subsequent digital signal processing and analysis;

[0090] After filtering and amplification, the signal will be sent to a special signal analysis algorithm module for further processing. For example, for the nozzle position signal transmitted by the grating sensor, the algorithm performs differential calculation, integral operation and other processing, and combines the mechanical structure parameters of the printer to accurately calculate the actual position coordinates of the nozzle at each moment and the motion parameters such as speed and acceleration, and judge whether the nozzle deviates from the predetermined position and whether the movement is abnormal according to the preset printing trajectory and the current printing progress. Based on these analysis results, the signal processing module will generate corresponding control signals. For example, when it is found that the nozzle position has deviated, a control signal for adjusting the speed and direction of the nozzle moving motor is generated and sent to the main control board, and the main control board drives the motor to perform the corresponding position correction operation; at the same time, according to the nozzle position signal and the printing task information transmitted by the print data processing module, an inkjet synchronization signal is generated according to a specific algorithm. The signal accurately specifies the key parameters such as when and where each nozzle starts to spray ink and the frequency of inkjet, ensuring that each nozzle can achieve synchronous and accurate inkjet printing on the surface of the round bottle, and ensuring the quality and integrity of the printed pattern.

[0091] The nozzle control module has a nozzle control board corresponding to each nozzle, and each nozzle control board receives a unified inkjet synchronization signal and a corresponding print data subset. Under the coordination of the inkjet synchronization signal, each nozzle control board will strictly control the nozzle to perform inkjet operation according to the same time reference and frequency requirements, ensuring that the ink droplets ejected by each nozzle can accurately converge at the corresponding position on the surface of the round bottle to form a continuous, uniform and complete pattern.

[0092] At the same time, the printhead control module also has the function of monitoring the status of the printhead. By setting sensors such as current detection and temperature detection in the printhead circuit, the working status of each printhead can be monitored in real time. For example, when a printhead is blocked, it will be manifested as abnormal current in the printhead or poor ink ejection. The corresponding printhead control board can detect the abnormal signal in time and feed the information back to the main board. The main board can then take corresponding maintenance measures to avoid affecting the quality and progress of the entire printing task due to the failure of individual printheads.

[0093] In order to adapt to different printing materials, printing requirements and ink characteristics, the nozzle control module supports flexible adjustment and optimization of various parameters of the nozzle. Users can set parameters such as ink drop size, jet frequency, and the distance between the nozzle and the bottle surface through the printer's operating interface. These setting information will be transmitted to the corresponding nozzle control board through the communication module. The nozzle control board adjusts the output signal of the drive circuit according to the received parameters, thereby changing the inkjet behavior of the nozzle. For example, when printing high-precision patterns, the ink drop size and jet frequency can be appropriately reduced to improve the clarity and color fineness of the pattern; when pursuing high-speed printing, the ink drop size and jet frequency can be appropriately increased, but at the same time, the ink adhesion and pattern quality need to be taken into account. Through continuous testing and optimization of nozzle parameters, the best parameter combination that meets different printing needs can be found to achieve high-quality and diversified round bottle printing effects.

[0094] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A control method for a multi-nozzle round bottle printer, characterized in that: The steps include: S1, import the picture to be printed into the system; S2, through the height measurement module, the algorithm scans the shape and position of the bottle; S3, according to the picture in step S1, the inkjet landing point position on the bottle is calculated by an algorithm; S4, converting the inkjet landing point position calculated in step S2 into printing data and transmitting it to the round bottle printer; S5, confirm the bottle position again, and start printing after it is correct.

2. The control method of a multi-nozzle round bottle printer according to claim 1, characterized in that: In step S1, the user imports the image file to be printed into the image processing software connected to the computer. The image processing software analyzes and converts the input image data according to the preset printing parameters, converts it into a printing data format suitable for the round bottle printer, and transmits it to the control system of the round bottle printer.

3. The control method of a multi-nozzle round bottle printer according to claim 1, characterized in that: In step S2, the height measuring module is specifically an infrared sensor, which obtains the height and shape of the bottle through the reflected infrared light.

4. The control method of a multi-nozzle round bottle printer according to claim 1, characterized in that: The step S3 further includes the following sub-steps: S31, based on the bottle shape and position information obtained in step S2, the software fits the imported image onto the three-dimensional surface model of the bottle according to a mapping rule; S32, the software will correspond each pixel point in the image to the actual physical position on the bottle surface according to the actual shape of the bottle and the position of the bottle in the printer coordinate system, and establish a one-to-one correspondence between the two-dimensional image pixel coordinates and the three-dimensional surface coordinates of the bottle; S33, according to the physical characteristics of the nozzle and the printing mode of the printer, the software further determines the specific landing point position corresponding to each pixel point when it is actually converted into an inkjet operation on the bottle surface through an inkjet landing point calculation algorithm and an established coordinate correspondence.

5. The control method of a multi-nozzle round bottle printer according to claim 1, characterized in that: In step S4, the data processing module in the printer control system reads the inkjet landing point position information data list generated in step S3, and then performs encoding conversion according to the data format that can be recognized and processed by the printer hardware.

6. The control method of a multi-nozzle round bottle printer according to claim 1, characterized in that: The step S5 specifically includes: pre-printing detection, the height measurement module works twice, quickly re-detects the shape and position of the bottle, obtains the latest bottle position information, and compares it with the initial position information previously stored in the system memory. If the comparison result shows that the position deviation of the bottle in the X, Y, and Z axis directions is within a very small error threshold range, it is considered that the bottle position is still accurate and no adjustment is required, and the printing stage can be directly entered; However, if a large deviation is detected in the bottle position, the system will automatically issue an alarm prompt message to inform the user that the bottle position has changed and the bottle placement needs to be readjusted.

7. A control system for a multi-nozzle round bottle printer, characterized in that: It includes a communication module, a data processing module, a signal processing module and a nozzle control module; The communication module is responsible for establishing information interaction between the various components of the printer and with external devices; the data processing module is responsible for comprehensive processing of various types of data received to ensure that they meet the execution requirements of various components of the printer; the signal processing module is responsible for collecting, converting and processing various physical signals involved in the operation of the printer; the nozzle control module, each nozzle corresponds to a nozzle control board, and each nozzle control board receives a unified inkjet synchronization signal and its corresponding print data subset.

8. The control system of a multi-nozzle round bottle printer according to claim 7, characterized in that: The communication module has designed protocols in layers and categories for different communication objects and data types. When interacting with a computer, it adopts a high-level protocol based on the TCP / IP protocol framework. On the basis of ensuring network communication compatibility, it adds functions that adapt to the large data transmission and real-time control requirements of the printer.

9. The control system of a multi-nozzle round bottle printer according to claim 7, characterized in that: The nozzle control module also includes a nozzle status monitoring function, which monitors the working status of each nozzle in real time by setting current detection and temperature detection sensors in the nozzle circuit.

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