Matrix variable relief letterpress flexo printing cylinder with full sealing dustproof structure

Abstract

The application discloses a matrix type variable relief plate flexographic printing cylinder with a full-sealing dustproof structure and belongs to the technical field of printing machinery. The application comprises a cylinder base body, a plunger matrix lifting assembly, a closed elastic sleeve assembly, a micro-positive pressure air supply dustproof assembly and a partition electric control driving assembly. The plunger array is installed in the sink hole of the base body, and the outside is surrounded by the sealing sleeve to form a closed cavity, and dust and water vapor are blocked from entering by means of the internal micro-positive pressure. The plunger is controlled by partition pulse self-locking, and the surface film is subjected to ink hanging modification treatment. The application solves the problems that the traditional variable plate roller is prone to jamming and cannot be mass-produced in a factory, can directly replace the original plate roller, does not need to make a printing plate, can switch patterns by one key, saves plate making cost, improves printing efficiency, and is suitable for use in carton ink flexographic printing equipment.

Description

Technical Field

[0001] This invention relates to the field of flexible printing machinery and equipment technology, specifically to a matrix-type variable letterpress flexographic printing cylinder used in corrugated cardboard box water-based flexographic printing machines and flexible packaging printing equipment. Background Technology

[0003] Traditional flexographic printing of cardboard boxes relies on photosensitive resin printing plates, which require manual plate placement, alignment, and color correction. The plate change process is cumbersome and time-consuming, making it extremely inefficient for cardboard box production with multiple batches and small orders. Moreover, the cost of printing plates and consumables accumulates to a high level over the years.

[0004] All existing plateless ejector pin rollers on the market have an exposed structure, with the plunger gaps directly exposed to the air. Dust, paper fibers, water, ink, and moisture from the carton workshop can easily enter the interior, causing the ejector pins to jam, malfunction, or fail to reset. This makes it impossible to achieve continuous mass production in the factory and can only be demonstrated in the laboratory, not used in practice.

[0005] Digital inkjet printing inks are expensive, printheads are prone to clogging, and maintenance is costly. It cannot replace traditional water-based flexographic printing, has poor print quality, and is not suitable for mass production of cardboard boxes.

[0006] Therefore, the industry has long lacked a mass-production-grade variable letterpress flexographic printing cylinder that is fully sealed, dustproof, waterproof, can work continuously for a long time, can change images with one click, and can directly replace old-fashioned printing rollers. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing variable plate rollers, such as poor sealing, easy needle jamming, inability to mass-produce, and high operating costs. It provides a matrix-type variable letterpress flexographic printing roller with a fully sealed dustproof structure. Through a fully enclosed sleeve structure combined with internal micro-positive pressure dustproof technology, it completely prevents dust and moisture from entering the interior, thus achieving stable industrial-scale plateless flexographic printing production.

[0009] A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure includes a cylinder base, a plunger matrix lifting assembly, a sealed elastic sleeve assembly, a micro-positive pressure air supply dustproof assembly, and a zoned electronic control drive assembly.

[0010] The roller body is a standard hollow steel roller, and the shaft ends adopt the universal plate roller size, which can directly replace the plate roller of a traditional flexographic printing machine without modifying the printing press structure. The outer circle of the roller is equipped with an array of countersunk holes for the orderly installation of miniature plungers, ensuring stable and non-shifting plunger lifting and lowering.

[0011] The plunger matrix lifting assembly consists of numerous permanent magnet pulse self-holding miniature plungers. The plunger tips feature a rounded structure to prevent puncturing the sealing film. The plungers are energized only momentarily during height adjustment and self-locking after positioning is complete, resulting in no continuous heat generation and a low failure rate. The plungers employ a zoned electronic control method, allowing for independent control of each zone, significantly reducing circuit costs and enabling fine dot printing.

[0012] The sealed elastic sleeve assembly completely encloses the plunger matrix structure, with both ends pressed tightly against the roller end face to form a completely closed cavity. The sleeve includes an inner buffer pad layer and an outer tensioned sealing film layer. The buffer pad layer protects the film from being punctured, and the film is air-expanded and tensioned at both ends to lock it in place. It does not loosen or deform during high-speed rotation, ensuring stable printing.

[0013] The micro-positive pressure air supply dustproof component connects to the internal air passage of the roller body, continuously supplying low-pressure dry air, making the internal air pressure of the cavity higher than the external air pressure, forming a weak airflow that overflows outward, blocking dust, water vapor and impurities from entering the cavity, and completely solving the problem of ejector pin jamming.

[0014] The zoned electronically controlled drive assembly includes conductive slip rings and zoned control circuit boards, enabling stable transmission of control signals while the rollers are rotating. An external control system can automatically calculate the plunger lifting height based on the printing pattern; a one-button reset allows all plungers to retract, restoring the roller surface to flatness and facilitating rapid switching of printing patterns.

[0015] The outer film undergoes plasma corona treatment, micron-level micropore processing, and hydrophilic coating modification, which significantly improves ink adhesion without compromising the seal. This solves problems such as ink not adhering to smooth films, ink shrinkage, and printing defects, resulting in printing effects comparable to traditional resin printing plates.

[0016] The invention has a simple and durable overall structure, requires very little maintenance, is compatible with traditional ink-based processes, can completely replace traditional plate printing, saves on the cost of plate making all year round, greatly improves plate changing efficiency, is suitable for harsh factory conditions, and can be used for long-term continuous mass production. Detailed Implementation

[0018] This embodiment uses a standard steel hollow roller as the roller base. The outer circumference of the roller is machined with a uniform array of countersunk holes. Arc-headed permanent magnet self-holding plungers are then sequentially installed and fixed. The plungers are divided into multiple control zones, each connected to a separate circuit board. The circuitry is connected to an external control system via a conductive slip ring at the shaft end, ensuring stable rotational operating signals.

[0019] A buffer pad layer and a tensioned, sealed film layer are fitted around the plunger, and both ends are air-expanded and locked to form a sealed cavity. The roller's air passage is connected to low-pressure, dry air to continuously maintain a slightly positive pressure dustproof environment inside. The film surface undergoes corona treatment, microporous coating modification, and hydrophilic coating treatment.

[0020] After the entire machine is assembled, dynamic balancing is performed, directly replacing the original printing rollers of the flexographic printing press. During use, the printing pattern is imported into the computer, and the system automatically controls the plunger's rise and fall to form the printing plate. Combined with the existing water-based ink system, normal printing can proceed. When changing plates, a single button resets the roller surface to ensure flatness, allowing for easy switching to new patterns; the operation is simple and efficient.

[0021] The above are preferred embodiments of the present invention. Any optimizations, improvements, or equivalent substitutions made under the structural principles of the present invention are within the protection scope of the present invention.

Claims

1. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure, characterized in that, The system includes a roller base, which is a hollow steel roller with an array of countersunk holes on its outer circumference; a plunger matrix lifting assembly installed inside the countersunk holes, containing multiple permanent magnet pulse self-holding micro plungers; a sealed elastic sleeve assembly that completely covers the plunger matrix lifting assembly and is sealed to both ends of the roller base to form a sealed cavity; and a micro-positive pressure air supply and dust prevention assembly that connects to the internal air passage of the roller base and continuously supplies dry compressed air into the sealed cavity. A partitioned electronically controlled drive assembly is used to control the lifting and lowering of the plungers in groups; the outer surface of the sealed elastic sleeve is modified and has a hydrophilic ink-retaining structure.

2. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure according to claim 1, characterized in that, The micro plunger has an arc-shaped top and is controlled by pulse instantaneous power supply. After the position is locked, the power is cut off to maintain the height. The plunger is divided into multiple blocks and controlled by partition circuit boards.

3. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure according to claim 1, characterized in that, The sealed elastic sleeve assembly consists of an inner buffer pad layer and an outer tensioned sealing film layer. The two ends of the film adopt an air-expansion tensioning and sealing structure to always maintain a tensioned state.

4. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure as described in claim 1, characterized in that, The micro-positive pressure air supply and dust prevention component maintains the internal air pressure of the sealed cavity higher than the external atmospheric pressure, forming an outward overflow airflow that prevents dust and water vapor from entering the cavity.

5. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure according to claim 1, characterized in that, The modification methods for the outer surface of the thin film are, in order, plasma corona treatment, processing of non-penetrating micron-sized pores, spraying of a hydrophilic coating, and uniform coating with water-based ink.

6. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure according to claim 1, characterized in that, The partitioned electronic control drive assembly includes a shaft-end conductive slip ring, which can stably transmit control signals under drum rotation conditions, and the external control system can reset all plungers with one key.

7. A matrix-type variable letterpress flexographic printing cylinder with a fully sealed dustproof structure according to claim 1, characterized in that, The roller base has standard roller dimensions at both ends, which can directly replace traditional flexographic printing rollers without requiring modifications to the main printing press equipment.