A shaft-driven encoder speed measuring device for a code jet printer

Abstract

The utility model provides a kind of shaft transmission type encoder speed measuring device for ink-jet printer, including encoder;Shaft end connector, for the coaxial connection of the input shaft of the encoder with the shaft end of the main drive shaft of the conveying belt of production line;Mounting bracket assembly, for the encoder is fixed in the vicinity of the shaft end of the main drive shaft.The utility model directly connects with the main drive shaft of conveying belt by coaxial connection of encoder through shaft end connector, and realizes firm installation by mounting bracket assembly, so that encoder can accurately, without sliding, directly detect the real-time rotational speed of main drive shaft, so as to output synchronous signal corresponding to conveying belt linear velocity strictly in real time, eliminate the speed signal delay, fluctuation and distortion caused by friction transmission, chain plate gap or skidding in traditional indirect speed measurement mode, significantly improve the real-time, accuracy and reliability of ink-jet synchronous control.

Description

Technical Field

[0001] This utility model relates to a shaft-driven encoder speed measuring device for inkjet printers. Background Technology

[0002] On packaging production lines for fast-moving consumer goods such as beer and beverages, printing production dates, batch numbers, and other information on bottles and cans is an essential process. Laser marking machines are widely used in this field due to their advantages such as high printing speed, high clarity, and no consumables required. To ensure accurate marking and complete characters, the printing action of the marking machine must be strictly synchronized with the speed of the packaging conveyor belt.

[0003] Currently, the commonly used synchronous speed measurement solution in the industry is as follows: a friction roller is installed on the side or above the conveyor belt. This roller rotates due to friction with the surface of the conveyor belt, driving a rotary encoder coaxially connected to it. The encoder indirectly calculates the linear speed of the conveyor belt by measuring the angular velocity of the roller and sends this speed signal to the inkjet printer controller to achieve synchronous triggering.

[0004] However, in actual production, especially in high-speed, continuous, and humid environments such as beer packaging, the existing technical solutions have the following inherent defects: 1) Low speed measurement accuracy and large signal fluctuations: Conveyor belts are usually made up of sections of chain plates or modules spliced ​​together, and their surfaces are not continuous and flat, with inherent gaps between the joints. When the friction rollers pass through these gaps, "tooth skipping" or brief slippage is very likely to occur. In addition, the uneven wear of the chain plates after long-term use further aggravates the instability of the roller rotation. This results in periodic or random fluctuations in the speed signal collected by the encoder, which cannot truly reflect the instantaneous linear speed of the conveyor belt; 2) Poor reliability and frequent maintenance: The friction rollers and the conveyor belt are in contact transmission, which is subject to continuous wear. In the humid environment of a brewery, where washing is sometimes required, the roller surface is prone to getting wet, slipping, or contaminated with sticky substances such as syrup, leading to a decrease in friction or even failure. Regular manual cleaning, inspection, or replacement of the rollers is required, increasing maintenance costs and downtime.

[0005] Therefore, packaging production lines urgently need a solution that can fundamentally overcome the drawbacks of contact speed measurement and provide a more accurate, stable, and maintenance-free synchronous speed signal. Utility Model Content

[0006] This invention provides a shaft-driven encoder speed measuring device for inkjet printers, which can effectively solve the above-mentioned problems.

[0007] This utility model is implemented as follows: A shaft-driven encoder speed measuring device for an inkjet printer, comprising: Encoder; A shaft-end connector is used to coaxially connect the input shaft of the encoder to the shaft end of the main drive shaft of the conveyor belt in the production line. Mounting bracket assembly for fixing the encoder to the vicinity of the shaft end of the main drive shaft; The encoder is used to directly detect the real-time rotational speed of the main drive shaft and output a synchronization signal corresponding to the linear speed of the conveyor belt.

[0008] The beneficial effects of this utility model are: (1) This utility model connects the encoder directly to the main drive shaft of the conveyor belt via the shaft end connector and achieves stable installation with the help of the mounting bracket assembly. This allows the encoder to accurately and directly detect the real-time speed of the main drive shaft without slippage, thereby outputting a synchronous signal that strictly corresponds to the linear speed of the conveyor belt in real time. This eliminates the speed signal delay, fluctuation and distortion caused by friction transmission, chain plate gap or slippage in the traditional indirect speed measurement method, and significantly improves the real-time performance, accuracy and reliability of the inkjet printing synchronous control. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0010] Figure 1 This is the front view of this utility model.

[0011] Figure 2 This is an exploded view of this utility model.

[0012] Figure 3 This is a structural schematic diagram of the flexible coupling of this utility model.

[0013] Explanation of icon numbers: 20. Mounting bracket assembly; 200. First base; 202. Bolt; 204. First nut; 206. Hollow sleeve; 208. Second base; 210. Second nut; 212. Washer; 30. Protective cover; 40. Main drive shaft; 50. Encoder; 60. Flexible coupling; 600. First elastic rubber ring; 602. Second elastic rubber ring; 604. First connector; 606. Second connector; 608. First connecting rod; 610. Locking cap; 612. Second connecting rod. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0015] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0016] Reference Figure 1-3 As shown, a shaft-driven encoder speed measuring device for an inkjet printer includes an encoder 50.

[0017] The shaft end connector is used to coaxially connect the input shaft of the encoder 50 to the shaft end of the main drive shaft 40 of the conveyor belt of the production line; the shaft end connector is a flexible coupling 60, which is used to compensate for the alignment error between the input shaft of the encoder 50 and the main drive shaft 40, and to absorb high-frequency vibrations during the transmission process.

[0018] Specifically, in mechanical installation, the encoder shaft 50 and the main drive shaft 40 are theoretically required to be perfectly concentric. However, in actual installation, there will always be slight radial, axial, or angular deviations. Rigid connections will generate huge additional stress due to these deviations, leading to bearing wear, shaft deformation, or even damage. The flexible coupling 60, through the deformation of its elastic elements (such as rubber, polyurethane, or metal diaphragms), allows and absorbs these alignment errors, protecting the precision encoder 50 and the main drive shaft 40. During operation, especially during start-up, shutdown, and load changes, the main drive shaft 40 of the production line will generate torsional vibrations. The damping characteristics of the flexible coupling 60 can filter and attenuate these high-frequency vibrations, preventing them from being directly transmitted to the encoder 50. Vibrations can cause unstable readings of the internal grating or magnetic grating of the encoder 50, generating pulse noise and affecting speed measurement accuracy. Therefore, the flexible coupling 60 plays the role of a "mechanical filter" in this case. The flexible coupling 60 includes a first elastic rubber ring 600 and a second elastic rubber ring 602, a first connector 604 and a second connector 606 respectively disposed on the top of the first elastic rubber ring 600 and the second elastic rubber ring 602, a first connecting rod 608 and a locking cap 610 disposed between the first connector 604 and the main drive shaft 40, and a second connecting rod 612 disposed at the end of the second connector 606 and the encoder 50.

[0019] Specifically, the first elastic rubber ring 600 and the second elastic rubber ring 602 are made of polymer materials such as polyurethane, rubber, or nylon. They are compressed and installed between two metal parts, mainly providing torsional elasticity and radial / angular flexibility. The first connector 604 and the second connector 606 are rigid metal structures connecting the elastic rubber rings to the drive shafts at both ends. Typically, each connector has claw-shaped, cylindrical, or arc-shaped protrusions on its inner side for embedding and driving the corresponding elastic rubber ring. Thus, when there is radial offset or angular deviation between the main drive shaft 40 and the encoder 50 shaft, the two elastic rubber rings 600... Uneven compression and tension will occur in 602. Due to the elasticity of the rubber ring material, they allow a certain relative displacement and deflection angle between the first connector 604 and the second connector 606 without generating a huge rigid reaction force. This effectively eliminates the additional stress caused by installation errors, protects the precision encoder 50 bearing and main drive shaft 40 support, and the torque is transmitted from the main drive shaft 40 to the encoder 50 through the rubber ring. The shear deformation of the elastic rubber ring provides flexible torque transmission characteristics, which can mitigate the impact load during start-up and stop. In extreme cases (such as instantaneous jamming), the deformation of the rubber ring reaches its limit or may slip, which can protect the internal structure of the encoder 50 from devastating overload damage to a certain extent.

[0020] Mounting bracket assembly 20 is used to fix encoder 50 near the shaft end of main drive shaft 40. Mounting bracket assembly 20 includes: a first base 200 and a second base 208 for mounting encoder 50; at least three adjustment components are distributed circumferentially along the first base 200 and the second base 208; wherein each adjustment component is capable of independent radial and / or axial fine adjustment to achieve precise alignment between the input shaft of encoder 50 and main drive shaft 40. The adjustment components include bolt 202, a first nut 204 disposed at one end of bolt 202, a hollow sleeve 206 for connecting to bolt 202, and a screw disposed on the second base 208 for threaded connection to hollow sleeve 206, one end of the screw being provided with a second nut 210 and a washer 212.

[0021] In actual use, the overall bracket is initially fixed to the vicinity of the bearing seat of the conveyor frame or main drive shaft 40 via its second base 208 or similar interface, completing coarse positioning. Subsequently, it enters the core precision alignment stage: the operator uses at least three adjusting components distributed circumferentially along the first base 200 and the second base 208, usually evenly arranged at 120 degrees, to form a stable adjustment plane. Each adjusting component is essentially a precision micro-motion mechanism, the core components of which include an adjusting screw connected to the first base 200 and a cooperating hollow sleeve 206. And a thrust or pull point acting on the second base 208. By using a tool to rotate the screw of each adjusting component, the extension or retraction distance of this point relative to the first base 200 can be changed independently. Since the second base 208 is elastically or floatingly connected to the first base 200 through all the adjusting components, the attitude of the second base 208 (together with the encoder 50 fixed thereon) in three-dimensional space can be precisely controlled by adjusting the displacement of these three (or more) support points respectively—including translation along the X, Y, and Z axes and minute rotations about these axes. This process allows the operator to observe the alignment of the coupling (using tools such as a dial indicator) while making fine adjustments until the concentricity and parallelism errors of the encoder 50 input shaft and the main drive shaft 40 are eliminated within the optimal compensation range of the flexible coupling 60. After alignment, the final locking stage begins: by tightening the locking elements such as the first nut 204 and the second nut 210 on each adjusting component, and by using the shim 212 to increase the anti-loosening performance, the relative position of the adjusting screw and the hollow sleeve 206, as well as the connection relationship between the entire adjusting component and the base, are fixed. Completely rigidly locked, at this point, all adjustment mechanisms transform from a movable state into a rigid support structure, forming a stable triangular (or multi-point) support frame that can resist long-term vibration and load during equipment operation, permanently maintaining the calibrated alignment state. The design of this assembly ingeniously solves the problem of achieving high-precision one-time installation in large industrial sites, decomposing the complex spatial alignment task into several simple linear adjustment operations, greatly improving installation efficiency, accuracy, and long-term operational reliability. It is a key guarantee mechanism for ensuring the superiority of the direct shaft speed measurement solution.

[0022] The encoder 50 directly detects the real-time rotational speed of the main drive shaft 40 and outputs a synchronization signal corresponding to the conveyor belt's linear speed. The rotational speed of the main drive shaft 40 has a definite and fixed geometric relationship with the conveyor belt's linear speed (determined by the drive shaft diameter). Therefore, by measuring the drive shaft's rotational speed, the conveyor belt speed can be uniquely and accurately calculated, fundamentally avoiding errors caused by friction slippage and chain plate gaps. The output "synchronization signal" is a clean and stable pulse stream, directly usable by the inkjet printer controller.

[0023] It also includes a protective cover 30, which surrounds the encoder 50. The end of the encoder facing the main drive shaft 40 has an opening through which the main drive shaft 40 passes. The opening has a dynamic sealing structure; the dynamic sealing structure is a labyrinth seal or a radial lip seal ring.

[0024] Specifically, the protective cover 30, as a rigid shell (typically made of metal such as aluminum alloy or stainless steel), completely surrounds the encoder 50, the connection portion of the flexible coupling 60, and the integrated signal conditioning module, forming a "safety cabin" relatively isolated from the external environment. However, since the main drive shaft 40 needs to penetrate this protective cover to connect to the coupling, there must be an annular opening at the end of the protective cover 30 facing the main drive shaft 40 for the shaft to pass through. This opening becomes a critical path for the intrusion of moisture, dust, and corrosive liquids (such as beer and cleaning agents). Therefore, this device incorporates a dynamic sealing structure at this opening. When a labyrinth seal is selected, the principle is to design a series of continuous, alternating annular narrow gaps and expansion chambers between the rotating shaft and the stationary shield. Any contaminants (water droplets, dust particles) attempting to penetrate along the shaft surface are partially adhered to due to viscosity when passing through the first narrow gap; upon entering the subsequent expansion chamber, the flow velocity drops sharply, the kinetic energy decreases, and the contaminants are thrown out or settled under centrifugal force (for liquids) or gravity, making it difficult for them to continuously pass through the entire tortuous path. This achieves a non-contact, zero-wear, long-term effective seal, especially effective against diffused dust and minor splashes. When a radial lip seal is selected, the principle is to use an annular seal with a sharp lip made of elastic rubber or PTFE material, which is fixed to the opening of the shield and the lip is tightly fitted to the surface of the rotating main drive shaft 40 under preload. This continuous contact forms a direct physical barrier, effectively preventing direct liquid penetration and providing better sealing performance. Whether it's the labyrinthine "blockage" or the lip-sealed "blockage," their common goal is to minimize or eliminate contact between external environmental factors (moisture, syrup, acidic or alkaline cleaning solutions, conductive dust) and the internal optical / magnetic components, circuit boards, and electrical connectors of the encoder 50. This protection ensures that the encoder 50's grating disk or magnetic grating will not experience signal attenuation or misreading due to contamination, and prevents short circuits and corrosion caused by moisture condensation or conductive contaminants. This guarantees the stability and accuracy of the speed measurement signal during long-term operation and extends the overall lifespan of the device, enabling this precision speed measuring device to adapt to the harsh production environments common in industries such as beer and beverage manufacturing, which are characterized by humidity and require regular high-pressure rinsing.

[0025] The protective cover 30 also houses a signal conditioning module, which is electrically connected to the encoder 50 and is used to filter, shape, or multiply the encoder's raw pulse signal. The signal conditioning module includes an RC filter circuit and a Schmitt trigger. Specifically, the signal conditioning module is typically integrated inside the protective cover 30, installed adjacent to the encoder 50, to minimize electromagnetic interference to the signal during the initial transmission phase. This module first uses an RC filter circuit, employing a low-pass network of resistors and capacitors, to filter out high-frequency noise and glitches coupled in from the operation of the motor and inverter, as well as long-distance transmission, retaining only the pure speed pulse. Subsequently, the processed signal enters a Schmitt trigger, a shaping circuit with hysteresis characteristics. This circuit transforms the filtered waveform, which may still have slowly varying edges or residual noise, into a square wave signal with steep edges and clean, regular logic levels. This significantly improves the signal's immunity to common-mode noise, ensuring that subsequent controllers (such as PLCs or dedicated inkjet controllers) can perform accurate counting and frequency measurement without errors or omissions. Thus, without changing the physical resolution of the encoder, the resolution of the speed signal is virtually increased, resulting in smoother speed feedback and facilitating higher-precision synchronous control.

[0026] principle: By creatively connecting the encoder 50 directly and coaxially to the conveyor belt main drive shaft 40 via a flexible coupling 60, replacing the traditional indirect speed measurement method that relies on friction transmission, signal fluctuations caused by chain plate gaps and slippage are eliminated, ensuring the authenticity and synchronization accuracy of the speed acquisition source. Furthermore, a mounting bracket assembly 20 with multi-degree-of-freedom independent fine-tuning functions is used to precisely calibrate and rigidly lock the encoder's spatial pose, ensuring long-term alignment accuracy and vibration resistance stability of the direct connection. Simultaneously, a protective cover 30 with a dynamic sealing structure (labyrinth or lip seal) creates a clean microenvironment for the encoder and its built-in signal conditioning module, resistant to moisture, dust, and washing. Finally, the signal conditioning module filters, shapes, and selectively multiplies the encoder's raw pulses at the signal source, outputting a high-quality synchronization signal with strong anti-interference capabilities and regular waveform to the inkjet printer controller. This series of interconnected mechanical structural innovations, integrated environmental protection, and front-end signal preprocessing technologies work synergistically to provide a continuous, stable, and high-precision speed reference for high-speed inkjet printing processes in harsh industrial environments.

[0027] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A shaft-driven encoder speed measuring device for an inkjet printer, characterized in that, include Encoder (50); A shaft end connector is used to coaxially connect the input shaft of the encoder (50) to the shaft end of the main drive shaft (40) of the conveyor belt of the production line; Mounting bracket assembly (20) for fixing the encoder (50) to the vicinity of the shaft end of the main drive shaft (40); The encoder (50) is used to directly detect the real-time rotational speed of the main drive shaft (40) and output a synchronization signal corresponding to the linear speed of the conveyor belt.

2. The shaft-driven encoder speed measuring device for an inkjet printer according to claim 1, characterized in that, The shaft end connector is a flexible coupling (60) used to compensate for the alignment error between the input shaft of the encoder (50) and the main drive shaft (40) and to absorb high-frequency vibrations during transmission.

3. The shaft-driven encoder speed measuring device for an inkjet printer according to claim 2, characterized in that, The flexible coupling (60) includes a first elastic rubber ring (600) and a second elastic rubber ring (602), a first connector (604) and a second connector (606) respectively disposed on the top of the first elastic rubber ring (600) and the second elastic rubber ring (602), a first connecting rod (608) and a locking cap (610) are disposed between the first connector (604) and the main drive shaft (40), and a second connecting rod (612) is disposed at the end of the second connector (606) and the encoder (50).

4. The shaft-driven encoder speed measuring device for an inkjet printer according to claim 1, characterized in that, The mounting bracket assembly (20) includes: First base (200) and second base (208) are used to mount the encoder (50); At least three adjustment components are distributed circumferentially along the first base (200) and the second base (208); Each of the adjustment components can be independently fine-tuned radially and / or axially to achieve precise alignment between the encoder (50) input shaft and the main drive shaft (40).

5. A shaft-driven encoder speed measuring device for an inkjet printer according to claim 4, characterized in that, The adjusting assembly includes a bolt (202), a first nut (204) disposed at one end of the bolt (202), a hollow sleeve (206) for connecting with the bolt (202), a screw disposed on the second base (208) and for threaded connection with the hollow sleeve (206), and a second nut (210) and a washer (212) disposed at one end of the screw.

6. A shaft-driven encoder speed measuring device for an inkjet printer according to claim 1, characterized in that, It also includes a protective cover (30) that surrounds the encoder (50) and has an opening at one end facing the main drive shaft (40) through which the main drive shaft (40) passes, and the opening is provided with a dynamic sealing structure.

7. A shaft-driven encoder speed measuring device for an inkjet printer according to claim 6, characterized in that, The dynamic sealing structure is a labyrinth seal or a radial lip seal ring.

8. A shaft-driven encoder speed measuring device for an inkjet printer according to claim 6, characterized in that, The protective cover (30) is also equipped with a signal conditioning module, which is electrically connected to the encoder (50) and is used to filter, shape or multiply the original pulse signal of the encoder.

9. A shaft-driven encoder speed measuring device for an inkjet printer according to claim 8, characterized in that, The signal conditioning module includes an RC filter circuit and a Schmitt trigger.

Images