A device for preparing the resistance value of a thermistor in a thermal printhead and a method for adjusting the resistance.

Abstract

This invention provides a device and method for preparing and adjusting the resistance value of a thermistor in a thermal printhead, relating to the technical field of thermal printhead equipment. It includes: an industrial control system and connected to the industrial control system a test shuttle storage system, a measured shuttle storage system, a shuttle handling robot, a substrate handling robot, a resistance adjustment probe station, and a marking and recognition vision system. This solution can improve the uniformity of the resistance value of the thermal printhead and contribute to increased production efficiency.

Description

Technical Field

[0001] This invention relates to the field of thermal printhead equipment technology, and more specifically, to a device for preparing the resistance value of a thermal printhead thermistor and a method for adjusting the resistance. Background Technology

[0002] Existing thermal printheads require probes for resistance adjustment during resistance preparation to ensure that the resistance between each print dot meets requirements. However, existing equipment suffers from poor uniformity, slow adjustment, and low reliability during resistance adjustment. Poor uniformity leads to quality defects such as inconsistent ink density in the printed print. Furthermore, current equipment for resistance preparation suffers from low automation levels and a high potential for resistance differences between multiple devices, resulting in varying quality and low stability of thermal printheads produced by different equipment. Summary of the Invention

[0003] This invention discloses a device for preparing the resistance value of a thermistor in a thermal printhead, which aims to improve the problems of poor resistance uniformity, poor stability and low efficiency of existing adjustment equipment.

[0004] The present invention adopts the following solution:

[0005] A thermistor resistance value preparation device for a thermal printhead includes: an industrial control system and a test shuttle storage system, a measured shuttle storage system, a shuttle handling robot, a substrate handling robot, and a resistance adjustment probe station connected to the industrial control system; wherein...

[0006] The test shuttle storage system is provided with an upper plate position. The test shuttle storage system is configured to convey the substrate containing the printhead to be adjusted to the upper plate position, and cooperate with the substrate pick-and-place robot to remove and transport the substrate to the adjustment probe station. The tested shuttle storage system is provided with a storage plate position. The tested shuttle storage system is configured to convey the substrate containing the adjusted printhead to the unloading position. A shuttle pick-and-place robot is provided between the upper plate position and the storage plate position. The shuttle pick-and-place robot is configured to transport the shuttle in the upper plate position to the storage plate position to store the adjusted substrate after the substrate in the shuttle in the upper plate position has been removed.

[0007] Multiple resistance adjustment probe stations are arranged side-by-side. Each probe station includes a vacuum adsorption platform, an XY-axis displacement mechanism, a Z-axis lifting mechanism, a rotation angle compensation mechanism, a vision positioning system, a needle cleaning device, a probe card, and a resistance adjustment housing. The probe card contains multiple resistance adjustment probes. The vacuum adsorption platform, positioned on the XY-axis displacement mechanism, adsorbs the thermal printhead substrate whose resistance is to be adjusted. The thermal printhead substrate has numerous heating points densely distributed at preset intervals in the XY direction. By moving the XY coordinates, a one-to-one correspondence is established between the heating points to be tested and the resistance adjustment probes on the probe card, satisfying the positioning and alignment requirements. The heating points on the thermal printhead substrate are grouped and tested according to the number of probes on the probe card until all resistance adjustments are completed. The vision positioning system, positioned above the vacuum adsorption platform, identifies and locates all heating points and conductive lines of the thermal printheads on the substrate under test, forming an XY coordinate system. The deviation angle of the heating points is calculated using this XY coordinate system to calculate... The required rotation angle of the probe card ensures that the resistance adjustment probes of the probe card are aligned with the conductive lines of the heating point under test in the XY direction. The Z-axis lifting mechanism is equipped with a mounting platform suitable for mounting the probe card and for driving the probe card to move up and down above the substrate so that each resistance adjustment probe on the probe card contacts the heating point electrode. The mounting platform is equipped with a rotation angle compensation mechanism to drive the probe card to rotate by the calculated angle of deviation of the heating point in the XY direction. The XY-axis displacement mechanism is adapted to move the substrate below the probe card to align the heating point electrode with the resistance adjustment probes on the probe card, ensuring that each heating point is adjusted one by one. The XY-axis displacement mechanism is equipped with a needle cleaning device to clean the probe tips on the probe card to remove oxides, contaminants, or perform horizontal correction after passivation. The probe card is connected to a resistance adjustment chassis, which provides corresponding pulse voltages to each probe on the probe card according to the number of probes to adjust the resistance of the corresponding heating point.

[0008] The substrate pick-and-place robot is adapted to move between the test shuttle storage system, the tested shuttle storage system and the adjustable probe stage, and includes a B group of arms and an A group of arms for simultaneously transporting the test substrate and the tested substrate in the same stroke.

[0009] Furthermore, a clamping mechanism is provided at the bottom of the upper plate position and the storage plate position. The clamping mechanism includes a clamping block and a telescopic mechanism. The telescopic mechanism is adapted to drive the clamping block to clamp inside the feed shuttle.

[0010] Furthermore, it also includes a conveyor track, which is disposed between the test shuttle storage system, the measured shuttle storage system and the resistance adjustment probe station, and the substrate picking and placing robot is disposed on the conveyor track and is adapted to move on the conveyor track.

[0011] Furthermore, the Z-axis lifting mechanism is equipped with a fine-tuning mechanism, which is suitable for adjusting the initial height of the probe card. The industrial control system is configured to drive the probe cleaning device to the bottom of the probe card to clean the probe when the probe bottom height is different and the potential fluctuation exceeds a preset range, based on the probe image information obtained by the vision lens and the potential change generated by the industrial control system during substrate testing. This reduces the resistance error caused by poor contact between the probe and the conductive line, and helps to obtain a more valuable actual resistance value.

[0012] Furthermore, a turntable for mounting probe cards is rotatably mounted on the mounting platform. The turntable has gear teeth. The rotation angle compensation mechanism includes a rotary motor mounted on the mounting platform. The output shaft of the rotary motor is connected to a gear assembly suitable for matching the gear teeth, so as to drive the turntable to rotate through the rotary motor, thereby performing rotational fine adjustment of the probe card on the horizontal plane.

[0013] Furthermore, an elastic fixing component is provided on one side of the mounting platform. The elastic fixing component includes two pressure blocks mounted on a cylinder. Each pressure block is provided with an elastic element to press the substrate firmly onto the vacuum adsorption platform from above when the substrate is placed on the vacuum adsorption platform, thereby maintaining effective levelness.

[0014] Furthermore, a spare conductive probe is provided on one side of the vacuum adsorption platform of each of the adjustable probe stations. The spare conductive probe is connected to a flipping mechanism. The spare conductive probe is adapted to be flipped by the flipping mechanism to connect the spare conductive probe to the common electrode on the substrate when the substrate to be adjusted placed on the vacuum adsorption platform needs to be connected to an external common electrode.

[0015] Furthermore, a marking mechanism is provided on the mounting platform. The marking mechanism is located on the side of the probe card to mark the point when the final resistance value of the heating point does not meet the preset target resistance value range.

[0016] The present invention also provides a method for adjusting resistance, using the aforementioned thermal printhead thermistor resistance value preparation device, comprising the following steps:

[0017] S1. Load the substrate using a shuttle, and store a certain amount of shuttles in the test shuttle storage system for later use.

[0018] S2. The A-group arm of the substrate picking and placing robot picks up a substrate from the shuttle to be adjusted, and then the B-group arm stores the adjusted substrate into the shuttle of the storage position. After that, the substrate picking and placing robot moves to the position of the identification vision system, reads the identification code on the substrate to be tested, and assigns it to the corresponding adjustment station through the industrial control system, so that the identification number of each thermal printhead substrate on the substrate is associated with the adjustment data of the corresponding station. When all the substrates in the shuttle of the upper board position are picked up, the shuttle of the storage position is transferred to the next station. Then, the empty shuttle of the upper board position is transported to the storage position by the picking and placing robot to store the adjusted substrate, thereby realizing the recycling of the shuttle to be tested and the shuttle of the tested, reducing the pressure of shuttle supply.

[0019] S3. According to the order of material calls, the substrate picking and placing robot moves to the resistance adjustment probe station where the resistance adjustment has been completed. The B group arm takes out the resistance-adjusted substrate from the resistance adjustment probe station, and then the A group arm places the substrate to be tested into the resistance adjustment probe station. If the corresponding resistance adjustment station shows that no board picking is required, the board placement operation is performed directly.

[0020] S4. The substrate pick-and-place robot returns to its initial position and executes the next cycle of substrate pick-and-place process; the station that has received the substrate begins the resistance adjustment operation; the resistance adjustment operation includes the following steps:

[0021] S41. Positioning: A vision positioning system comprehensively scans the entire substrate for heating points, then performs high-precision positioning and rotation angle compensation to ensure that each probe accurately contacts the electrode of the heating point for reading resistance and adjusting resistance upon power-on. Specifically: After the substrate is in position, the probe card moves down to measure the resistance at the heating point. The industrial control system compares the measured resistance value with the set upper and lower limit resistance values. If the measured resistance value exceeds the preset upper and lower limit resistance range or is abnormal, the probe card is lifted and the probe is re-inserted by a preset small displacement to the left or right of the substrate to ensure accurate contact between the probe and the adjusting electrode of the heating point. If the resistance value still does not match the preset upper and lower limit resistance after the number of re-insertions exceeds a predetermined value, a dot is marked at that point.

[0022] S42, Resistance adjustment: The number of times the resistance of the heating point is adjusted each time depends on the number of probes on the probe card. Each probe corresponds to a conductive line, and the conductive line is connected to the heating point or common electrode.

[0023] S421. Before adjusting the resistance, measure the resistance value of a standard resistor on each probe of the probe card for calibration to ensure the accuracy of the resistance reading each time.

[0024] S422. When the measured actual resistance value is within the preset upper and lower limit values, the resistance at each heating point is adjusted. The resistance value is adjusted by connecting the probe to the resistance adjustment chassis to output pulse voltage to adjust the resistance value of each heating point closer to the preset target resistance value.

[0025] S423. Repeat steps S422 until the difference between the actual resistance value and the preset target resistance value is within the allowable range. In each cycle of step S422, if the difference between the actual resistance value of the corresponding heating point and the preset target resistance value meets the standard, it is judged as qualified. In the next cycle, qualified heating points will no longer be energized for resistance adjustment. Unqualified resistance values ​​are judged based on the resistance value of the last adjustment after multiple cycles of energization and resistance adjustment. If the resistance value does not meet the target resistance value, it is judged as defective and marked with a dot.

[0026] S43. Clean the probe tip. After repeating the above resistance adjustment process a predetermined number of times, clean the probe tip to remove oxides and smooth it, so that the probe tip is on a horizontal plane to ensure the accuracy of the probe's resistance measurement each time.

[0027] S44. Cross-test: Within a preset time, the substrate whose resistance has been adjusted by one of the resistance adjustment probe stations is directly transferred to one of the other two resistance adjustment probe stations for resistance measurement. The measured resistance value is then compared with the resistance value measured during actual resistance adjustment to determine whether the probe card resistance measurement result of the actual resistance adjustment station meets the consistency requirements with the measurement results of other resistance adjustment probe stations. This cross-validation method is used to determine whether the standard resistor inside the resistance adjustment probe station is in normal working condition.

[0028] Furthermore, it also includes: S45, when the resistance value tested in S44 deviates from the resistance value measured during resistance adjustment by more than a preset value, the substrate is moved to the third resistance adjustment probe station for resistance measurement, and the measurement data is compared with the resistance values ​​measured by the other two stations. When the resistance values ​​measured by two resistance adjustment probe stations are similar, the other resistance adjustment probe station is inspected; when the resistance values ​​measured by the three resistance adjustment probe stations are significantly different, all resistance adjustment probe stations are inspected.

[0029] Beneficial effects:

[0030] In the above manner, the loading and unloading shuttle robot can transport the loaded shuttle to the tested shuttle storage system for storing the substrate after resistance adjustment, realizing the recycling of the tested shuttle and the tested shuttle, and reducing the pressure on shuttle supply; by setting up B group arms and A group arms on the substrate loading and unloading robot, efficient switching and supply make the cycle consistent, making full use of the resistance adjustment device's capabilities, and improving efficiency and production capacity; by setting up a resistance adjustment probe station, the quality defects of existing thermal printheads, such as inconsistent ink density due to poor uniformity in resistance preparation, as well as the technical problems of slow resistance adjustment, low stability and poor reliability during resistance preparation, can be solved. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of a thermal printhead thermistor resistance value preparation device according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the substrate picking and placing robot arm of a thermal printhead thermistor resistance value preparation device according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the connection structure of the test shuttle storage system, the measured shuttle storage system, and the shuttle picking and placing robot in a thermal printhead thermistor resistance value preparation device according to an embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of the resistance adjustment probe stage of a thermistor resistance preparation device for a thermal printhead according to an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the XY axis displacement mechanism of the resistance adjustment probe stage of a thermal printhead thermistor resistance value preparation device according to an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the resistance adjustment mechanism of the resistance adjustment probe station of a thermal printhead thermistor resistance value preparation device according to an embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram of the structure of the adjustable probe stage of a thermal printhead thermistor resistance preparation device according to an embodiment of the present invention, with the mounting stage hidden.

[0038] Figure 8 This is a schematic diagram of the marking mechanism of the resistance adjustment probe station of a thermal printhead thermistor resistance value preparation device according to an embodiment of the present invention.

[0039] Icons: Adjustable probe stage 100, vacuum adsorption platform 110, XY axis displacement mechanism 120, Z axis lifting mechanism 130, lifting assembly 131, guide rod 132, fine-tuning mechanism 140, vision positioning system 150, probe card 160, needle washing device 170, flipping mechanism 181, spare conductive probe 182, mounting platform 191, marking point mechanism 192, turntable 193, fixing mechanism 194, locking rod 1941, fine-tuning rod 1942, elastic fixing assembly 195, rotation angle compensation mechanism 196, test shuttle storage system 200, upper plate position 210, clamping mechanism 220, tested shuttle storage system 300, plate storage position 310, shuttle picking and placing robot 400, substrate picking and placing robot 500, B group arm 510, A group arm 520, conveyor track 600. Detailed Implementation

[0040] Example 1

[0041] Combination Figures 1 to 8 As shown, this embodiment provides a thermistor resistance value preparation device for a thermal printhead, including: an industrial control system and a test shuttle storage system 200, a tested shuttle storage system 300, a shuttle handling robot 400, a substrate handling robot 500, and a resistance adjustment probe station 100 connected to the industrial control system; wherein,

[0042] The test shuttle storage system 200 is provided with an upper plate position 210. The test shuttle storage system 200 is configured to convey a substrate containing a printhead to be adjusted to the upper plate position 210, and cooperate with the substrate pick-and-place robot 500 to remove and transport the substrate to the adjustment probe station 100. The tested shuttle storage system 300 is provided with a storage plate position 310. The tested shuttle storage system 300 is configured to convey a substrate containing a thermally adjusted printhead to the unloading position. A pick-and-place robot 400 is provided between the upper plate position 210 and the storage plate position 310. The pick-and-place robot 400 is configured to transport the shuttle in the upper plate position 210 to the storage plate position 310 to store the adjusted substrate after the substrate in the shuttle in the upper plate position 210 has been removed.

[0043] The identification vision system (not shown) is adapted to visually identify the identification mark on the substrate after the substrate pick-up and drop robot 500 takes the substrate out of the test shuttle in the upper plate position 210, and match the visual identification result with the adjustment probe station 100 to which the pick-up and drop robot 500 is about to go, so as to associate the data of the substrate with the adjustment probe station 100 through the industrial control system.

[0044] Multiple adjustable probe stations 100 are arranged side-by-side. Each adjustable probe station 100 includes a vacuum adsorption platform 110, an XY-axis displacement mechanism 120, a Z-axis lifting mechanism 130, a rotation angle compensation mechanism 196, a vision positioning system 150, a needle washing device 170, a probe card 160, a flip electrode, and an adjustable probe housing. The probe card 160 has multiple adjustable probes. The vacuum adsorption platform 110 is mounted on the XY-axis displacement mechanism 120 and is used to adsorb the thermal printhead substrate whose resistance value is to be adjusted. The thermal printhead substrate to be adjusted has probes spaced at preset intervals in the XY direction. The thermal printhead substrate is densely covered with numerous heating points. By moving the XY coordinates, a one-to-one correspondence is established between the heating points under test and the resistance adjustment probes of the probe card 160, thus meeting the requirements for positioning and alignment. The heating points on the thermal printhead substrate are grouped and tested according to the number of probes on the probe card 160 until all have undergone resistance adjustment. The visual positioning system 150 is positioned above the vacuum adsorption platform 110 to identify all heating points of the thermal printhead on the substrate under test and the conductive lines of the heating points, forming an XY coordinate system. The deviation angle of the heating points is calculated from this XY coordinate system to determine the required rotation of the probe. The angle of the probe card 160 is adjusted so that the adjustable probes of the probe card 160 are aligned with the conductive lines of the heating point under test in the XY extension direction, ensuring that the adjustable probes can accurately align with the heating point; the Z-axis lifting mechanism 130 is provided with a mounting platform 191 suitable for mounting the probe card 160, and is suitable for driving the probe card 160 to rise and fall above the substrate so that each adjustable probe on the probe card 160 contacts the heating point electrode; the mounting platform 191 is provided with a rotation angle compensation mechanism 196 for driving the probe card 160 to rotate by a predetermined angle; the XY axis displacement mechanism 120 is suitable for The substrate is moved below the probe card 160 to bring the heating electrode into contact with the resistance adjustment probe on the probe card 160, ensuring that each heating point is adjusted one by one. A needle cleaning device 170 is provided on the XY axis displacement mechanism 120. The needle cleaning device 170 is adapted to clean the probe tips on the probe card 160 to remove oxides, contaminants, or to perform horizontal correction on the probes after passivation. The probe card 160 is connected to the resistance adjustment cabinet, which provides corresponding pulse voltages to each probe on the probe card according to the number of probes to adjust the resistance of the corresponding heating point.

[0045] The substrate handling robot 500 is adapted to move between the test shuttle storage system 200, the tested shuttle storage system 300, and the adjustable probe stage 100. It includes a B group of arms 510 and an A group of arms 520 for simultaneously transporting the test substrate and the tested substrate in the same stroke.

[0046] Combination Figures 1 to 3As shown, in this embodiment, both the test shuttle storage system 200 and the tested shuttle storage system 300 are equipped with a conveying mechanism. The conveying mechanism drives the shuttle to move, transporting the shuttle containing the test substrate to the upper plate position 210 within the test shuttle storage system 200, and conveying the shuttle containing the tested substrate from the storage plate position 310 within the tested shuttle storage system 300. The upper plate position 210 and the storage plate position 310 are equipped with a clamping mechanism 220 at their bottoms. The clamping mechanism 220 includes a clamping block and a telescopic mechanism, the telescopic mechanism being adapted to drive the clamping block to clamp within the shuttle. The clamping mechanism 220 also includes a lifting device for driving the clamping block to rise during clamping to clamp within the shuttle. Positioning can be achieved through this clamping mechanism 220. The material handling robot 400 is positioned above the upper plate position 210 and the storage plate position 310. It includes a gripper, a lifting mechanism, and a traversing mechanism. The gripper is mounted on the lifting mechanism, and the lifting mechanism is mounted on the traversing mechanism, thereby enabling the material shuttle to be transported from the upper plate position 210 to the storage plate position 310.

[0047] Combination Figures 1 to 3 As shown, a conveying track 600 is provided between the test shuttle storage system 200, the tested shuttle storage system 300, and the adjustable probe station 100. The substrate picking and placing robot 500 is disposed on the conveying track 600 and is adapted to move on the conveying track 600. The substrate picking and placing robot 500 includes a B-group arm 510 and an A-group arm 520, which are mounted on a lifting assembly. The lifting assembly drives the B-group arm 510 and A-group arm 520 to move up and down simultaneously. The B-group arm 510 and A-group arm 520 are equipped with extension cylinder assemblies to drive the rods for picking up and placing the substrate. During picking up and placing, the extension cylinder assemblies and the lifting assembly work together to efficiently switch between picking and placing, ensuring a smooth cycle and fully utilizing the capabilities of the resistance adjustment device to improve efficiency and production capacity. In this embodiment, a single substrate picking and placing robot 500 can meet the needs of multiple resistance adjustment probe stations 100 for testing substrates. From picking up the substrate to be tested and storing the tested substrate to placing and placing the substrate at the resistance adjustment probe station 100, the entire process can be completed in one cycle, satisfying the one-to-many capability and optimizing the manufacturing process.

[0048] In this embodiment, the identification vision system can visually identify the markings on the substrate after the substrate pick-up and drop-down robot 500 removes the substrate from the test shuttle. These markings can be inkjet printing, laser marking, marks, or printed patterns, and the marking content can be simple numbers, barcodes, QR codes, or patterns. The visual recognition result is matched with the trimming probe station 100 that the substrate pick-up and drop-down robot 500 is about to move to, to associate the data. The identification vision system can be a vision device or a scanning device. For example, the identification vision system includes an OCR recognition device located in the direction of the conveyor track and connected to the industrial control system. The OCR recognition device is used to read the identification code on the substrate and distribute the identification code to the corresponding trimming probe station 100 through the industrial control system. The identification vision system can associate the data of the substrate and the trimming probe station 100 through the industrial control system, thereby allowing the industrial control system to obtain real-time data on the substrate currently being processed and the substrates already processed by each trimming probe station 100.

[0049] In this embodiment, a large number of heating points are densely distributed on the thermal printhead substrate to be adjusted at preset intervals in the XY direction. By moving the XY coordinates, a one-to-one correspondence is formed between the heating points to be tested and the adjustment probes of the probe card 160, so as to meet the positioning and alignment requirements. The heating points on the thermal printhead substrate are grouped and tested according to the number of probes on the probe card 160 until all are adjusted. The vision positioning system 150 can be used to identify all the heating points of the thermal printhead on the substrate to be tested and the conductive lines of the heating points to form an XY coordinate system, and the deviation angle of the heating points can be calculated from the XY coordinate system. The coordinate data of the heating points acquired by the vision positioning system 150 is used by the industrial control system to control the XY axis displacement mechanism 120 and the rotation angle compensation mechanism 196 to adjust the position, so that the heating points are precisely aligned with the adjustment probes.

[0050] In this embodiment, three resistance adjustment probe stations 100 can be provided, arranged side by side, allowing for simultaneous resistance adjustment. Combined with... Figures 4 to 5 As shown, in this embodiment, the XY axis displacement mechanism 120 and the Z axis lifting mechanism 130 are mounted on the base, and the vacuum adsorption platform 110 is detachably mounted on the XY axis displacement mechanism 120. Clamping devices are also provided around the vacuum adsorption platform 110, which can be used to correct the position of the substrate placed on the vacuum adsorption platform 110 and to assist in clamping to prevent displacement during machine displacement or resistance adjustment.

[0051] The needle cleaning device 170 is mounted on the XY-axis displacement mechanism 120. When needle cleaning is required, it moves to a position below the probe holder 160, and the movement causes the probes on the probe holder 160 to be smoothed on the needle cleaning device 170. In one embodiment, the needle cleaning device 170 can be sandpaper, used to smooth the tips of the probes. Preferably, a blowing device is provided on one side of the sandpaper to blow air while cleaning the needles, preventing probe debris from adhering to the probe tips and affecting subsequent testing and resistance adjustment. Furthermore, the needle cleaning device 170 can also be used to perform overall calibration after the resistance adjustment probes have been passivated, improving the accuracy of resistance adjustment.

[0052] Combination Figures 4 to 8 As shown, the Z-axis lifting mechanism 130 includes a lifting assembly 131 mounted on a base and two guide rods 132 parallel to the lifting direction of the lifting assembly 131. The mounting platform 191 is connected to the guide rods 132 via a slider. The fine-tuning mechanism 140 is fixed to the slider, with one end contacting the top of the lifting assembly 131. The lifting assembly 131 acts on the fine-tuning mechanism 140, thereby driving the mounting platform 191 to move up and down. Here, the fine-tuning mechanism 140 can be adjusted by a high-precision gear set in conjunction with a motor to control the micrometer assembly. The lifting assembly 131 includes a linear motor, which is located on one side of the two guide rods 132 and is used to drive the slider to rise. When the extension shaft of the linear motor retracts, the slider and the mounting platform 191 descend under their own gravity. The end of the micrometer assembly on the fine-tuning mechanism 140 contacts the end of the extension shaft of the linear motor to support the slider. Thus, when adjusting the micrometer assembly, the mounting platform 191 and the probe clip 160 on the mounting platform 191 can be finely adjusted up and down. This is because the precision of linear motors or other lifting mechanisms is insufficient to meet the requirements of fine-pitch adjustments. When there is a small distance between the probe on the probe card 160 and the heating point on the substrate, a large potential fluctuation will occur during resistance measurement, resulting in fluctuations in the measured resistance value. These fluctuations may be caused by a small contact point between the probe and the heating point, or by a large drop in the probe tip, causing the tip to bend (the tip is flexible). If the linear motor is directly started for lifting in this situation, the probe may completely detach from the substrate, or the probe may move downwards by too much, damaging the probe. Therefore, by setting up a fine-tuning mechanism 140 for adjustment, the precision can reach 1µm, effectively preventing the above situations from occurring.

[0053] Combination Figures 4 to 8As shown, the visual positioning system 150 includes a lifting device and a visual lens mounted on the lifting device. The visual lens is adapted to capture images of the heating electrode positions on the substrate and can move to the probe position under the drive of the lifting device to obtain image information of the probe and transmit the image information to the industrial control system. The visual lens is equipped with a fine-tuning component for adjusting the position and height of the visual lens. After a period of use and after adjustment by the rotation angle compensation mechanism 196, if the industrial control system can still detect that the resistance or potential fluctuation of the measured heating point exceeds the preset range, it may be that the probe card 160 has not moved into position. At this time, the visual lens can be driven down to the probe position for image capture and identification. Based on the probe image information acquired by the visual lens, if it is found that the probe is not fully in contact with the heating point on the substrate, the probe card 160 is driven down a certain scale distance by the fine-tuning mechanism 140 until the resistance or potential fluctuation detected by the industrial control system becomes smaller or the fluctuation range is within the preset range; if the visual lens detects that the tip of the probe is bent, then If the probe card 160 descends to a large height, the fine-tuning mechanism 140 can be used to control the probe card 160 to rise a certain scale distance until the resistance or potential fluctuation detected by the industrial control system becomes smaller, or the fluctuation range is within the preset range. If the fine-tuning mechanism 140 cannot make the resistance or potential fluctuation detected by the industrial control system smaller, or cannot make the fluctuation range within the preset range, it indicates that the probes on the probe card 160 are of different lengths. In this case, the needle cleaning device 170 is driven to the bottom of the probe card 160 to grind and clean it, so as to ensure that the tip height of each probe is consistent, thereby improving the uniformity of the resistance value during resistance adjustment.

[0054] Combination Figures 4 to 8As shown, a turntable 193 for mounting probe cards 160 is rotatably mounted on the mounting platform 191. The turntable 193 has gear teeth. The rotation angle compensation mechanism 196 includes a rotary motor mounted on the mounting platform 191. The output shaft of the rotary motor is connected to a gear assembly adapted to match the gear teeth, so as to drive the turntable 193 to rotate, thereby finely adjusting the probe card 160 left and right. A probe card 160 fixing mechanism 194 is provided on the turntable 193. The fixing mechanism 194 includes several locking rods 1941 and fine-adjusting rods 1942. The locking rods 1941 are adapted to lock onto opposite sides of the probe card 160, and the fine-adjusting rods are adapted to press against the rear end of the probe card 160. The locking rods 1941 and fine-adjusting rods 1942 are used to maintain the probe card 160 horizontally. In this embodiment, the probe card 160 is installed in the fixing mechanism 194 and locked by adjusting the locking rod 1941. Then, it is finely adjusted by the fine-tuning rod 1942 to keep the probe card 160 horizontal within the fixing mechanism 194. An elastic fixing component 195 is provided on one side of the mounting platform 191. The elastic fixing component 195 includes two pressure blocks mounted on a cylinder. Each pressure block is provided with an elastic element to press the substrate firmly against the vacuum adsorption platform 110 from above when the substrate is placed on it. A marking mechanism 192 is provided on the mounting platform 191. The marking mechanism 192 is located on the side of the probe card 160 to mark points when an abnormal resistance value is detected at a corresponding position on the substrate.

[0055] In this solution, by setting a rotation angle compensation mechanism 196, it can work in conjunction with the fine-tuning mechanism 140. When the difference between the measured actual resistance value and the set target resistance value exceeds the preset target value, or when the measured resistance value is abnormal, the probe card 160 is lifted by the lifting mechanism. Then, the rotation angle compensation mechanism 196 controls the probe card 160 to move left and right respectively for fine-tuning. The fine-tuning range is about 1~10um. Repeat the left and right fine-tuning and needle insertion. If the resistance value is read normally and the difference between the actual resistance value and the set target resistance value is within the preset target value allowable range, resistance adjustment can be performed. If after repeated fine-tuning multiple times, the resistance value still cannot be read normally, or the difference between the actual resistance value and the set target resistance value still exceeds the preset target value, it is determined that there is a significant problem with the heat point in that area. The marking point mechanism 192 marks the point, and no resistance adjustment is performed. Here, the rotation angle compensation mechanism 196 can adjust the problem of the probe not being accurately aligned with the heat point due to the positional error between the probe and the heat point. Repeated left and right fine-tuning is performed to make the probe and the heat point accurately aligned. During the test, the resistance value of the adjustable chassis is collected in real time.

[0056] Combination Figure 4 and Figure 5As shown, in another embodiment, a spare conductive probe 182 is provided on one side of the vacuum adsorption platform 110. The spare conductive probe 182 is connected to a flipping mechanism 181. The spare conductive probe 182 is adapted to be flipped by the flipping mechanism 181 to connect with the electrode on the substrate when the substrate to be adjusted on the vacuum adsorption platform 110 has no common electrode or the common electrode is ineffective. By providing the spare conductive probe 182, this mechanism can adapt to different types of substrate testing, especially to substrates with and without common electrodes. When adjusting the resistance of a substrate with a common electrode, the common electrode on the substrate is electrically connected to the adjustment chassis. The probe, as another electrode, forms a circuit with the common electrode, thereby allowing resistance measurement of the heating point. Then, the resistance is adjusted by outputting a pulse voltage through the adjustment chassis. During adjustment, each heating point is adjusted independently from one end to the other. Heating points with a resistance value that meets the requirements do not need adjustment. For heating points with a large resistance value, pulse voltage adjustment is required. The method of adjusting the resistance using pulse voltage is existing technology and will not be described in detail here. When the substrate does not have a common electrode, the flipping mechanism 181 flips the spare conductive probe 182 to a position close to the substrate, so that the substrate is connected to the spare conductive probe 182, and the spare conductive probe 182 serves as one of the electrodes of the substrate.

[0057] By setting the fine-tuning mechanism 140 as the rotation angle compensation mechanism 196, the position of the probe card 160 can be finely adjusted in conjunction with the industrial control system before resistance adjustment, thereby effectively solving the problem of poor resistance adjustment reliability. At the same time, in conjunction with the needle washing device 170, the uniformity of resistance adjustment can be improved, solving the quality defect of uneven ink density in the printing of existing thermal printheads due to poor uniformity in resistance preparation.

[0058] Example 2

[0059] The present invention also provides a method for adjusting resistance, using the aforementioned thermal printhead thermistor resistance value preparation device, comprising the following steps:

[0060] S1. Load the substrate using a shuttle, and store a certain amount of shuttles in the test shuttle storage system 200 for later use.

[0061] S2. The A-group arm of the substrate pick-up and placement robot 500 picks up a substrate from the shuttle to be adjusted, and then the B-group arm stores the adjusted substrate into the shuttle of the storage position. After that, the substrate pick-up and placement robot 500 moves to the position of the identification vision system, reads the identification code on the substrate to be tested, and assigns it to the corresponding adjustment station through the industrial control system, so that the identification number of each thermal printhead substrate on the substrate is associated with the adjustment data of the corresponding station. When all the substrates in the shuttle of the upper board position are picked up, the shuttle of the storage position is transferred to the next station. Then, the empty shuttle of the upper board position is transported to the storage position by the pick-up and placement robot to store the adjusted substrate, thereby realizing the recycling of the shuttle to be tested and the shuttle of the tested, reducing the pressure of shuttle supply.

[0062] S3. According to the order of material calls, the substrate picking and placing robot moves to the resistance adjustment probe station where the resistance adjustment has been completed. The B group arm takes out the resistance-adjusted substrate from the resistance adjustment probe station, and then the A group arm places the substrate to be tested into the resistance adjustment probe station. If the corresponding resistance adjustment station shows that no board picking is required, the board placement operation is performed directly.

[0063] S4. The substrate pick-and-place robot returns to its initial position and executes the next cycle of substrate pick-and-place process; the station that has received the substrate begins the resistance adjustment operation; the resistance adjustment operation includes the following steps:

[0064] S41. Positioning: A vision positioning system comprehensively scans the entire substrate for heating points, then performs high-precision positioning and rotation angle compensation to ensure that each probe accurately contacts the electrode of the heating point for reading resistance and adjusting resistance upon power-on. Specifically: After the substrate is in position, the probe card moves down to measure the resistance at the heating point. The industrial control system compares the measured resistance value with the set upper and lower limit resistance values. If the measured resistance value exceeds the preset upper and lower limit resistance range or is abnormal, the probe card is lifted and the probe is re-inserted by a preset small displacement to the left or right of the substrate to ensure accurate contact between the probe and the adjusting electrode of the heating point. If the resistance value still does not match the preset upper and lower limit resistance after the number of re-insertions exceeds a predetermined value, a dot is marked at that point.

[0065] S42, Resistance adjustment: The number of times the resistance of the heating point is adjusted each time depends on the number of probes on the probe card. Each probe corresponds to a conductive line, and the conductive line is connected to the heating point or common electrode.

[0066] S421. Before adjusting the resistance, measure the resistance value of a standard resistor on each probe of the probe card for calibration to ensure the accuracy of the resistance reading each time.

[0067] S422. When the measured actual resistance value is within the preset upper and lower limit values, the resistance at each heating point is adjusted. The resistance value is adjusted by connecting the probe to the resistance adjustment chassis to output pulse voltage to adjust the resistance value of each heating point closer to the preset target resistance value.

[0068] S423. Repeat steps S422 until the difference between the actual resistance value and the preset target resistance value is within the allowable range. In each cycle of step S422, if the difference between the actual resistance value of the corresponding heating point and the preset target resistance value meets the standard, it is judged as qualified. In the next cycle, qualified heating points will no longer be energized for resistance adjustment. Unqualified resistance values ​​are judged based on the resistance value of the last adjustment after multiple cycles of energization and resistance adjustment. If the resistance value does not meet the target resistance value, it is judged as defective and marked with a dot.

[0069] S43. Clean the probe tip. After repeating the above resistance adjustment process a predetermined number of times, clean the probe tip to remove oxides and smooth it, so that the probe tip is on a horizontal plane to ensure the accuracy of the probe's resistance measurement each time.

[0070] S44. Cross-test: Within a preset time, the substrate whose resistance has been adjusted by one of the resistance adjustment probe stations is directly transferred to one of the other two resistance adjustment probe stations for resistance measurement. The measured resistance value is then compared with the resistance value measured during actual resistance adjustment to determine whether the probe card resistance measurement result of the actual resistance adjustment station meets the consistency requirements with the measurement results of other resistance adjustment probe stations. This cross-validation method is used to determine whether the standard resistor inside the resistance adjustment probe station is in normal working condition.

[0071] In this embodiment, in step S423, after multiple cycles of resistance adjustment, the resistance value of the last adjustment is used for judgment; this is the first judgment. If the first judgment is unqualified, a second resistance measurement and adjustment is performed by lifting the probe card and moving it to the left by a small displacement; this is the second judgment. If the second judgment is still unqualified, a third resistance measurement and adjustment is performed by lifting the unqualified hot spot back to its initial position and then moving it to the right by a small displacement. Any product that passes any of the three judgments is considered qualified. If the resistance value is still unqualified in the third judgment, a mark is made. This solution can reduce the probability of false testing and reduce substrate waste caused by false testing.

[0072] In this embodiment, during the testing phase, when an abnormal resistance value is detected, fine adjustments can be made in four directions (up, down, left, and right) using the rotation angle compensation mechanism 196 and the fine-tuning mechanism 140 to prevent abnormal resistance values ​​due to positional errors. If, after adjustment using the fine-tuning mechanism 140 and the rotation angle compensation mechanism 196, the resistance value of a certain heat-generating point is still abnormal or fluctuates significantly, the probe tip on the probe card 160 is ground flat using the probe cleaning device 170 to solve the problem of inaccurate detection of some heat-generating points due to different probe heights.

[0073] During the resistance adjustment stage, the resistance is adjusted by repeatedly inserting needles. The resistance value of the last adjustment is used to determine whether it meets the target resistance value. If it does not meet the target resistance value, a mark is made.

[0074] It should be noted that in this embodiment, each substrate includes multiple thermal printheads, and each thermal printhead has multiple heating points. The probe card 160 applies resistance adjustment to one of the thermal printheads at a time. When a non-compliant thermal printhead is detected, a mark is made, and then the other thermal printheads are tested and their resistance adjusted. After a certain number of resistance adjustments, the probe tip is cleaned to remove oxides and smoothed, ensuring the probe tip is on a horizontal plane.

[0075] The solution in this embodiment can achieve better resistance uniformity, ensuring the saturation of ink dot color and the fineness of printed characters. It can also achieve high-speed resistance adjustment, continuous cycle, and high utilization rate.

[0076] It should be understood that the above are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

[0077] The accompanying drawings used in the above description of the embodiments only illustrate certain embodiments of the present invention 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.

Claims

1. A device for preparing the resistance value of a thermistor in a thermal printhead, characterized in that, include: The industrial control system, and connected to the industrial control system, a test shuttle storage system, a tested shuttle storage system, a shuttle handling robot, a substrate handling robot, a resistance adjustment probe station, and a marking and recognition vision system; wherein... The test shuttle storage system is provided with an upper plate position. The test shuttle storage system is configured to convey the substrate containing the printhead to be adjusted to the upper plate position, and cooperate with the substrate pick-and-place robot to remove and transport the substrate to the adjustment probe station. The tested shuttle storage system is provided with a storage plate position. The tested shuttle storage system is configured to convey the substrate containing the adjusted printhead to the unloading position. A shuttle pick-and-place robot is provided between the upper plate position and the storage plate position. The shuttle pick-and-place robot is configured to transport the shuttle in the upper plate position to the storage plate position to store the adjusted substrate after the substrate in the shuttle in the upper plate position has been removed. The identification vision system is adapted to visually identify the identification mark on the substrate after the substrate pick-up and drop robot takes the substrate out of the test shuttle at the upper plate position, and match the visual identification result with the adjustment probe station that the pick-up and drop robot is about to go, so as to associate the data of the substrate and the adjustment probe station through the industrial control system. Multiple resistance adjustment probe stations are arranged side-by-side. Each probe station includes a vacuum adsorption platform, an XY-axis displacement mechanism, a Z-axis lifting mechanism, a rotation angle compensation mechanism, a vision positioning system, a needle cleaning device, a probe card, and a resistance adjustment housing. The probe card contains multiple resistance adjustment probes. The vacuum adsorption platform, positioned on the XY-axis displacement mechanism, adsorbs the thermal printhead substrate whose resistance is to be adjusted. The thermal printhead substrate has numerous heating points densely distributed at preset intervals in the XY direction. By moving the XY coordinates, a one-to-one correspondence is established between the heating points to be tested and the resistance adjustment probes on the probe card, satisfying the positioning and alignment requirements. The heating points on the thermal printhead substrate are grouped and tested according to the number of probes on the probe card until all are adjusted. The vision positioning system, positioned above the vacuum adsorption platform, identifies and locates all heating points and conductive lines of the thermal printheads on the substrate under test, forming an XY coordinate system. The deviation angle of the heating points is calculated using this XY coordinate system to calculate... The required rotation angle of the probe card ensures that the resistance adjustment probes of the probe card are aligned with the conductive lines of the heating point under test in the XY extension direction. The Z-axis lifting mechanism is equipped with a mounting platform suitable for mounting the probe card and for driving the probe card to move up and down above the substrate so that each resistance adjustment probe on the probe card contacts the heating point electrode. The mounting platform is equipped with a rotation angle compensation mechanism to drive the probe card to rotate by the calculated angle of deviation of the heating point in the XY direction. The XY-axis displacement mechanism is adapted to move the substrate below the probe card to align the heating point electrode with the resistance adjustment probes on the probe card, ensuring that each heating point is adjusted one by one. The XY-axis displacement mechanism is equipped with a needle cleaning device to clean the probe tips on the probe card to remove oxides and contaminants and to perform horizontal correction after passivation. The probe card is connected to a resistance adjustment chassis, which provides corresponding pulse voltages to each probe on the probe card according to the number of probes to adjust the resistance of the corresponding heating point. The substrate pick-and-place robot is adapted to move between the test shuttle storage system, the tested shuttle storage system and the adjustable probe stage, and includes a B group of arms and an A group of arms for simultaneously transporting the test substrate and the tested substrate in the same stroke.

2. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, The bottom of the upper plate position and the storage plate position are provided with a clamping mechanism. The clamping mechanism includes a clamping block and a telescopic mechanism. The telescopic mechanism is adapted to drive the clamping block to clamp in the feed shuttle.

3. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, It also includes a conveyor track, which is disposed between the test shuttle storage system, the tested shuttle storage system and the resistance adjustment probe station, and the substrate picking and placing robot is disposed on the conveyor track and is adapted to move on the conveyor track.

4. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, The Z-axis lifting mechanism is equipped with a fine-tuning mechanism, which is suitable for adjusting the initial height of the probe card. The industrial control system is configured to drive the probe cleaning device to the bottom of the probe card to clean the probe when the probe bottom height is different and the potential fluctuation exceeds a preset range, based on the probe image information obtained by the vision lens and the potential change generated by the industrial control system during substrate testing. This reduces the resistance error caused by poor contact between the probe and the conductive line, and helps to obtain a more valuable actual resistance value.

5. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, A turntable for mounting probe cards is rotatably mounted on the mounting platform. The turntable has gear teeth. The rotation angle compensation mechanism includes a rotary motor mounted on the mounting platform. The output shaft of the rotary motor is connected to a gear assembly suitable for matching the gear teeth, so as to drive the turntable to rotate through the rotary motor, thereby performing rotational fine adjustment of the probe card on the horizontal plane.

6. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, An elastic fixing component is provided on one side of the mounting platform. The elastic fixing component includes two pressure blocks mounted on a cylinder. Each pressure block is provided with an elastic element to press the substrate firmly onto the vacuum adsorption platform from above when the substrate is placed on the vacuum adsorption platform, thereby maintaining effective levelness.

7. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, Each of the adjustable probe stations has a spare conductive probe on one side of the vacuum adsorption platform. The spare conductive probe is connected to a flipping mechanism. The spare conductive probe is adapted to be flipped by the flipping mechanism to connect to the common electrode on the substrate when the substrate to be adjusted on the vacuum adsorption platform needs to be connected to an external common electrode.

8. The apparatus for preparing the thermistor resistance value of a thermal printhead according to claim 1, characterized in that, The mounting platform is equipped with a marking mechanism, which is located on the side of the probe card to mark points when the final resistance value of the heating point does not meet the preset target resistance value range.

9. A method for adjusting resistance, characterized in that, The apparatus for preparing the resistance value of a thermal printhead thermistor according to any one of claims 1-8 includes the following steps: S1. Load the substrate using a shuttle, and store a certain amount of shuttles in the test shuttle storage system for later use. S2. The substrate picking and placing robot has a set of arms A and a set of arms B; Group A arms pick up a substrate from the shuttle to be adjusted, and then Group B arms store the adjusted substrate into the shuttle at the storage position. After that, the substrate picking and placing robot moves to the identification vision system position, reads the identification code of the substrate to be tested on Group A arms, and assigns it to the corresponding adjustment station through the industrial control system, so that the identification number of each thermal printhead substrate on the substrate is associated with the adjustment data of the corresponding station. When all the substrates in the shuttle at the upper plate position are picked up, the shuttle at the storage position is transferred to the next station. Then, the empty shuttle at the upper plate position is transported to the storage position by the picking and placing robot to store the adjusted substrate, thereby realizing the recycling of the shuttle to be tested and the shuttle that has been tested, reducing the pressure on the shuttle supply. S3. According to the order of material calls, the substrate picking and placing robot moves to the resistance adjustment probe station where the resistance adjustment has been completed. The B group arm takes out the resistance-adjusted substrate from the resistance adjustment probe station, and then the A group arm places the substrate to be tested into the resistance adjustment probe station. If the corresponding resistance adjustment station shows that no board picking is required, the board placement operation is performed directly. S4. The substrate pick-and-place robot returns to its initial position and executes the next cycle of substrate pick-and-place process; the station that has received the substrate begins the resistance adjustment operation; the resistance adjustment operation includes the following steps: S41. Positioning: A vision positioning system comprehensively scans the entire substrate for heating points, then performs high-precision positioning and rotation angle compensation to ensure that each probe accurately contacts the electrode of the heating point for reading resistance and adjusting resistance upon power-on. Specifically: After the substrate is in position, the probe card moves down to measure the resistance at the heating point. The industrial control system compares the measured resistance value with the set upper and lower limit resistance values. If the measured resistance value exceeds the preset upper and lower limit resistance range or is abnormal, the probe card is lifted and the probe is re-inserted by a preset small displacement to the left or right of the substrate to ensure accurate contact between the probe and the adjusting electrode of the heating point. If the resistance value still does not match the preset upper and lower limit resistance after the number of re-insertions exceeds a predetermined value, a dot is marked at that point. S42, Resistance adjustment: The number of times the resistance of the heating point is adjusted each time depends on the number of probes on the probe card. Each probe corresponds to a conductive line, and the conductive line is connected to the heating point or common electrode. S421. Before adjusting the resistance, measure the resistance value of a standard resistor on each probe of the probe card for calibration to ensure the accuracy of the resistance reading each time. S422. When the measured actual resistance value is within the preset upper and lower limit values, the resistance at each heating point is adjusted. The resistance value is adjusted by connecting the probe to the resistance adjustment chassis to output pulse voltage to adjust the resistance value of each heating point closer to the preset target resistance value. S423. Repeat steps S422 until the difference between the actual resistance value and the preset target resistance value is within the allowable range. In each cycle of step S422, if the difference between the actual resistance value of the corresponding heating point and the preset target resistance value meets the standard, it is judged as qualified. In the next cycle, qualified heating points will no longer be energized for resistance adjustment. Unqualified resistance values ​​are judged based on the resistance value of the last adjustment after multiple cycles of energization and resistance adjustment. If the resistance value does not meet the target resistance value, it is judged as defective and marked with a dot. S43. Clean the probe tip. After repeating the above resistance adjustment process a predetermined number of times, clean the probe tip to remove oxides and smooth it, so that the probe tip is on a horizontal plane to ensure the accuracy of the probe's resistance measurement each time. S44. Cross-test: Within a preset time, the substrate whose resistance has been adjusted by one of the resistance adjustment probe stations is directly transferred to one of the other two resistance adjustment probe stations for resistance measurement. The measured resistance value is then compared with the resistance value measured during actual resistance adjustment to determine whether the probe card resistance measurement result of the actual resistance adjustment station meets the consistency requirements with the measurement results of other resistance adjustment probe stations. This cross-validation method is used to determine whether the standard resistor inside the resistance adjustment probe station is in normal working condition.

10. The resistance adjustment method according to claim 9, characterized in that, Also includes: S45. When the resistance value measured in S44 deviates from the resistance value measured during resistance adjustment by more than a preset value, the substrate is moved to the third resistance adjustment probe station for resistance measurement. The measurement data is then compared with the resistance values ​​measured by the other two stations. If the resistance values ​​measured by two resistance adjustment probe stations are similar, the other resistance adjustment probe station is inspected. If the resistance values ​​measured by the three resistance adjustment probe stations differ significantly, all resistance adjustment probe stations are inspected.

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