Thermal printing head detection circuit

Abstract

A thermal printing head detection circuit belongs to the technical field of thermal printing head detection and comprises a high-precision linear power supply, a detection control mainboard and an upper computer, the high-precision linear power supply is connected with a product, the product is arranged on an automatic probe station for movably controlling the measurement position of the product, the product and the automatic probe station are connected with the detection control mainboard, and the upper computer is connected with the detection control mainboard. The detection control mainboard is connected with the upper computer, and the upper computer is connected with the high-precision linear power supply through the detection control mainboard. The thermal printing head detection circuit provided by the utility model can detect electrode deficiency and poor resistance value of a heating body in the production process of the thermal printing head, and avoids waste caused by continuous production of subsequent processes.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermal print head detection, and particularly relates to a thermal print head detection circuit. Background Art

[0002] With the continuous improvement and progress of the information technology industry, thermal printing technology has been widely used for its ultra-small size, high speed, high image quality, low power consumption, high reliability, and environmental friendliness. As the core component of printing technology, defective products will be produced during the production process of the thermal print head. The detection link of defective products is of great significance, which can avoid the outflow of defective products and low production efficiency.

[0003] During the production process of the thermal print head, many types of defects will occur. The main defects in the previous process are mainly electrode short circuit, open circuit, electrode shortage, and abnormal resistance value of the heating element. At present, electrode short circuit, open circuit, and the resistance value of the heating element can be detected by resistance measurement, while it is very difficult to detect the shortage of electrodes by resistance measurement. The missing electrodes will cause the color of the Dot to fade during the final product printing, or even cause electrode open circuit defects. The resolution of the thermal print head is generally 200dpi - 600dpi, the electrode width is between 50 microns and 30 microns, and a single print head consists of more than a thousand electrodes. The method of visual inspection with a high-power microscope by hand is inefficient and impossible to achieve, and can only flow to the final printing detection. This method not only causes waste in the subsequent process production but also increases the input of time cost, thus affecting the overall efficiency. Summary of the Utility Model

[0004] To solve the defects existing in the prior art, a thermal print head detection circuit is provided, which includes a high-precision linear power supply, a detection control main board, and a host computer. The high-precision linear power supply is connected to the product. The product is arranged on an automatic probe table that moves to control the measurement position of the product. The product, the automatic probe table are connected to the detection control main board, the detection control main board is connected to the host computer, and the host computer is connected to the high-precision linear power supply through the detection control main board.

[0005] Further, the detection control main board includes a multi-channel triode circuit, an MCU control circuit, a serial port communication circuit, a relay circuit, a power supply circuit, an AD acquisition module, a constant current generation circuit, a control panel, and an accessory circuit. The MCU control circuit is connected to the serial port communication circuit, the relay circuit, the power supply circuit, the AD acquisition module, the constant current generation circuit, the control panel, and the accessory circuit. The constant current generation circuit is connected to the AD acquisition module, and the multi-channel triode circuit is connected to the AD acquisition module.

[0006] Further, the multi-channel triode circuit has 128 channels.

[0007] Furthermore, the high-precision linear power supply is the source of the circuit constant current power supply and has serial communication.

[0008] Furthermore, the host computer communicates with the detection and control main board through serial communication.

[0009] The beneficial effects of the present utility model are as follows: A thermal print head detection circuit of the present utility model can detect electrode deficiency defects and heating element resistance value defects during the production process of the thermal print head, avoiding waste caused by continuous production in subsequent processes. Description of the Drawings

[0010] Figure 1 is the composition diagram of the detection and control main board of the thermal print head detection circuit of the present utility model;

[0011] Figure 2 is the unit composition diagram of the thermal print head detection circuit of the present utility model;

[0012] Figure 3 is the constant current generation circuit diagram of the thermal print head detection circuit of the present utility model;

[0013] Figure 4 is the AD acquisition module circuit diagram of the thermal print head detection circuit of the present utility model;

[0014] Figure 5 is the control panel circuit diagram of the thermal print head detection circuit of the present utility model;

[0015] Figure 6 is the power supply circuit diagram of the thermal print head detection circuit of the present utility model;

[0016] Figure 7 is the MCU control circuit diagram of the thermal print head detection circuit of the present utility model;

[0017] Figure 8 is the serial communication circuit diagram of the thermal print head detection circuit of the present utility model;

[0018] Figure 9 is the relay circuit diagram of the thermal print head detection circuit of the present utility model;

[0019] Figure 10 is the multi-channel triode circuit diagram of the thermal print head detection circuit of the present utility model;

[0020] Figure 11 is the external terminal diagram of the multi-channel triode circuit of the thermal print head detection circuit of the present utility model;

[0021] Figure 12 is the accessory circuit diagram of the thermal print head detection circuit of the present utility model;

[0022] Figure 13It is a diagram showing the formation of the electrodes of the thermal print head of the present utility model;

[0023] Figure 14 It is an enlarged view of area A in the diagram showing the formation of the electrodes of the thermal print head of the present utility model;

[0024] Figure 15 It is a diagram showing the formation of the heating element of the thermal print head of the present utility model;

[0025] Figure 16 It is an enlarged view of area B in the diagram showing the formation of the electrodes of the thermal print head of the present utility model. Detailed implementation mode

[0026] A thermal print head detection circuit, as Figures 1 - 12 shown, includes a high-precision linear power supply, a detection control main board, and a host computer. The high-precision linear power supply is connected to the product, and the product is arranged on an automatic probe table that moves to control the measurement position of the product. The product, the automatic probe table are connected to the detection control main board, and the detection control main board is connected to the host computer. The host computer is connected to the high-precision linear power supply through the detection control main board.

[0027] Among them, the detection control main board includes a multi-channel triode circuit, an MCU control circuit, a serial communication circuit, a relay circuit, a power supply circuit, an AD acquisition module, a constant current generation circuit, a control panel, and an accessory circuit. The MCU control circuit is connected to the serial communication circuit, the relay circuit, the power supply circuit, the AD acquisition module, the constant current generation circuit, the control panel, and the accessory circuit. The constant current generation circuit is connected to the AD acquisition module, and the multi-channel triode circuit is connected to the AD acquisition module.

[0028] Among them, the multi-channel triode circuit has 128 channels.

[0029] Among them, the high-precision linear power supply is the source of the circuit constant current power supply and has serial communication.

[0030] Among them, the host computer conducts serial communication with the detection control main board.

[0031] Working principle: As Figure 2 shown, a thermal print head detection circuit is composed of the following several units:

[0032] 1. Detection control main board: It has a multi-channel triode circuit (128 channels) ( Figures 10 - 11 ), an MCU control circuit ( Figure 7 ), a serial communication circuit ( Figure 8 ), a relay circuit ( Figure 9 ), a power supply circuit ( Figure 6 ), an AD acquisition module ( Figure 4 ), a constant current generation circuit ( Figure 3 ), a control panel (Figure 5 ), accessory circuit( Figure 12 ).

[0033] 2. High-precision linear power supply: Provides a constant current power supply. This constant current source is a purchased device and has serial communication.

[0034] 3. Host computer: Installed with measurement control software, can perform serial communication with the detection control main board. This software platform can set measurement parameters according to different product requirements to judge the output results.

[0035] 4. Automatic probe station: Moves to control the measurement position of the product.

[0036] Working mode:

[0037] I. Electrode deficiency measurement process

[0038] 1. Load the product to be measured (the product electrode has been formed, the electrode is made of metallic aluminum with a thickness of 0.6 microns, as Figures 13 - 14 shown) onto the automatic probe station, adjust the measurement program, and move the electrode of the product to be measured under the detection probe.

[0039] 2. The host computer sets the detection program according to the product parameter requirements, drives the first path in the triode circuit (128 paths) to open through the serial port to the detection control main board. The detection control main board drives the high-precision linear power supply to load and output the rated current to the electrode through the relay KS3 and the current-limiting resistor R18 (1K ohm) in the relay circuit, applies the rated constant current I1 to a single Dot point electrode of the product heating element for a duration of t1, closes the first path in the triode circuit (128 paths), and lasts for a duration of t2. The above-mentioned opening of the first path in the triode circuit (128 paths) for t1 and closing of the first path in the triode circuit (128 paths) for t2 are repeated for the set number of times X. Open the second path in the triode circuit (128 paths) through the control main board and repeat the same process as the control operation of the first path until the last path (the 128th path) is completed, and then close the relay KS3 in the relay circuit.

[0040] 3. Open the first path in the triode circuit (128 paths) through the detection control main board, apply a constant current I2 to a single Dot point electrode of the product heating element through the constant current generation circuit, open the AD acquisition module through the MCU and read the measured voltage value Vn. Vn is collected and calculated by the MUC control circuit to obtain the resistance value Rn = Vn / I2 - R18. Rn transmits data to the host computer through the serial communication circuit. The detection control main board closes the first path in the triode circuit (128 paths), opens the second path in the triode circuit (128 paths) through the control main board, and repeats the same process as the control operation of the first path until the last path (the 128th path) is completed. n is the electrode serial number, and R18 is the current-limiting resistor of 1K ohm for the electrode to load the constant current, as Figure 9As shown, V1 to Vn represent the voltage values collected across the series connection of the electrodes under test and R18, and R1 to Rn represent the resistance values of the electrodes under test.

[0041] 4. The host computer receives the measurement data of Rn through serial communication with the detection control main board, makes a judgment and outputs the detection result, and drives the automatic probe station through the serial port to move the product to the next measurement position.

[0042] 5. The host computer repeats the above steps 1 to 4 according to the requirements of the number of electrodes of the product until all the electrodes n of the product are measured.

[0043] 6. Principle of judgment: According to the requirements of different products for the current-carrying capacity of the electrodes, adjust the constant current output value I1, the current duration t1, and the number of repetitions X to test the influence of the electrode deficiency degree on the current-carrying capacity of the electrodes. Electrodes with serious deficiencies will be damaged under the action of the current output value I1, the continuous current duration t1, and the number of repetitions X, and then the resistance value of the electrodes will increase. By detecting the change in the resistance value of the electrodes, the deficient electrodes can be found. The host computer judges the electrode deficiency based on the measured electrode resistance value Rn after applying a constant current output to the electrodes.

[0044] II. Measurement process of the resistance value of the heating element

[0045] 1. Load the product under test (the heating element of the product has been formed through the etching process, and the material of the heating element is Tasio2, as Figures 15 - 16 shown) onto the automatic probe station, adjust the measurement program, and move the product under test under the detection probe.

[0046] 2. Open the first path in the triode circuit (128 paths) through the detection control main board, apply a constant current I3 to a single Dot electrode of the heating element of the product through the constant current generation circuit, open the AD acquisition module and the resistance measurement circuit through the MCU to read the measured voltage value Vm, and obtain the resistance value Rm through the MUC control IC circuit by collecting and calculating Rm = Vm / I3 - Rn. Rm transmits data to the host computer through the serial communication circuit. The detection control main board closes the first path in the triode circuit (128 paths), and opens the second path in the control triode circuit (128 paths) through the control main board, and repeats the same process as the first path control until the last path (the 128th path) is completed.

[0047] 3. The host computer receives the measurement data of Rm through serial communication with the detection control main board, makes a judgment and outputs the detection result, and drives the automatic probe station through the serial port to move the product to the next measurement position.

[0048] 4. The host computer repeats the above steps a to c according to the requirements of the number of heating elements of the product until all the heating elements of the product are measured.

[0049] 5. Judgment basis principle: According to the constant current output value I3 and the voltage value Vm collected by the AD acquisition module at both ends of the electrodes of the heating element, the resistance value Rm is calculated through the resistance measurement circuit. The upper computer judges that the heating element is defective based on the measured electrode resistance value. Rm = Vm / I3 - Rn

[0050] (n is the electrode serial number, m is the corresponding serial number of the heating element under the nth electrode, Rn is the corresponding resistance value of the electrode connected to the heating element, and Rm is the corresponding resistance value of the heating element)

[0051] III. Resistance measurement and calibration process of the heating element

[0052] Description of the completion of the product electrode and the completion of the product heating element

[0053] 1. The completion of the product electrode means that after the electrodes are formed during the manufacturing process of the thermal printer head, all the electrodes are manufactured and in a measurable state. The electrodes are made of aluminum metal with a thickness of 0.6 microns and are formed on the ceramic substrate through PVD, exposure, and etching processes. (Reference Figures 13 - 14 )

[0054] 2. The completion of the heating element means that after the heating element is formed during the manufacturing process of the thermal printer head, the electrodes are connected to the heating element and in a detectable state. The heating element is made of TaSIO2 with a thickness of 0.1 micron and is formed on the ceramic substrate through PVD, exposure, and etching processes, with electrodes attached to the surface. (Reference Figures 15 - 16 )

[0055] Description of the control panel

[0056] 1. The control panel is used for parameter program selection and input in the MCU

[0057] Description of the relay circuit, as Figure 9 shown

[0058] 1. One-way relay KS3 is used to control the on / off of the constant current input of the externally connected high-precision linear power supply;

[0059] 2. One-way relay KS2 sends a feedback end signal to the automatic probe station through high and low level signals.

[0060] 3. One-way relay KS1 controls the connection of the externally connected standard resistor through the on / off of the relay, and is used to verify and correct the measurement value result (for debugging backup).

[0061] Description of the automatic probe station

[0062] 1. The automatic probe station is an externally purchased device and is used to align the measurement electrode position of the product and measure and align the measurement position of the heating element.

[0063] 2. The start and end signals of the detection control mainboard communicate with the automatic probe station through the high and low levels of the relay circuit.

[0064] Auxiliary circuit

[0065] 1. The auxiliary circuit is the connection terminal, reset button and the control mainboard related supporting capacitors, resistors, LED and other components circuits.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A thermal print head detection circuit, characterized in that: It includes a high-precision linear power supply, a detection and control main board, and a host computer. The high-precision linear power supply is connected to the product. The product is set on an automatic probe table that moves and controls the product measurement position. The product and the automatic probe table are connected to the detection and control main board. The detection and control main board is connected to the host computer. The host computer is connected to the high-precision linear power supply through the detection and control main board.

2. The thermal print head detection circuit according to claim 1, characterized in that: The detection control mainboard includes a multi-channel triode circuit, an MCU control circuit, a serial communication circuit, a relay circuit, a power supply circuit, an AD acquisition module, a constant current generating circuit, a control panel, and an auxiliary circuit. The MCU control circuit is connected to the serial communication circuit, the relay circuit, the power supply circuit, the AD acquisition module, the constant current generating circuit, the control panel, and the auxiliary circuit. The constant current generating circuit is connected to the AD acquisition module, and the multi-channel triode circuit is connected to the AD acquisition module.

3. The thermal print head detection circuit according to claim 2, characterized in that: The multi-channel triode circuit has 128 channels.

4. The thermal print head detection circuit according to claim 1, characterized in that: The high-precision linear power supply is the source of the circuit's constant current power supply and has serial port communication.

5. The thermal print head detection circuit according to claim 1, characterized in that: The host computer communicates with the detection control mainboard through a serial port.

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