Thermal film printing method and device

Abstract

The invention relates to the technical field of thermal printing, and specifically discloses a thermal sheet printing method and device, comprising: obtaining data information to be printed, searching for corresponding dot matrix data in a built-in character library built into a printing system according to the byte data content; and performing current control on a heating line corresponding to each printing point on the thermal sheet based on the dot matrix data, including: obtaining a printing point value of each printing point in the dot matrix data; judging and obtaining a power-on signal; obtaining a printing point target grayscale value, and calculating and obtaining a target power value of the heating line on the printing point based on the printing point target grayscale value; controlling and adjusting the current value of the heating line to reach the target current value, so that the power value of the heating line is adjusted to the target power value; controlling a thermal print head to heat, and then performing thermal printing, to ensure that the grayscale of the thermally printed data meets the requirements; and ensuring that the problem of unqualified printing grayscale occurs during thermal printing and multi-point printing.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal printing, and in particular to a thermal sheet printing method and device. Background Art

[0002] Thermal printing technology was first used in fax machines. Its basic principle is to convert the data received by the printer into a dot matrix signal to control the heating of the thermal unit, and heat and develop the thermal coating on the thermal paper. Thermal printers have been widely used in POS terminal systems, banking systems, medical equipment and other fields. Thermal printers can only use special thermal paper, which is coated with a coating that changes color when heated. Thermal printing technology has emerged by utilizing this characteristic of the thermal coating.

[0003] From the above working principle, it can be known that thermal printing can only print out black and white binary images. When a thermal printer prints, it is necessary to add text watermarks with different shades of effects. For example, when a courier prints a courier slip with a thermal printer, there is a need to add a watermark. The prior art is to process the print data of the printed text and control the temperature of the thermal print head based on the grayscale information of the print data. Since the text and watermark of thermal printing are both grayscale text, there may be problems such as printing too fast or unstable power of the heating line during the printing process, resulting in the text content not being displayed normally, affecting the recognizability of the text. Summary of the invention

[0004] The object of the present invention is to provide a thermal film printing method and device to solve the above-mentioned background problems.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A thermal film printing method, step 1: obtaining data information to be printed, the data information to be printed includes text data information; converting the text data information into hexadecimal byte data;

[0007] Step 2: After receiving the byte data from the data acquisition module, the corresponding dot matrix data is searched in the built-in character library of the printing system according to the content of the byte data;

[0008] Step 3: Obtain dot matrix data, and based on the dot matrix data, control the current of the heating line corresponding to each printing point on the thermal sheet, burn on the thermal paper to complete the printing of data information; including:

[0009] S01: Obtain the printing point value of each printing point in the dot matrix data; determine and obtain the power-on signal;

[0010] S02: based on the power-on signal, obtaining a target grayscale value of the printing point, and recording the target grayscale value of the printing point as DS, and calculating a target power value Pw of the heating line on the printing point based on the target grayscale value DS of the printing point;

[0011] S03: Obtain the target power value Pw, and based on the target power value Pw, control and adjust the current value of the heating line to reach the target current value ID, so that the power value of the heating line is adjusted to the target power value Pw; at this time, control the thermal print head to heat, maintain the heating time t1, and then perform thermal printing.

[0012] As a further solution of the present invention: in the step 2, the dot matrix data is a set of binary numbers that describe the character data, and the state of each printing dot in the dot matrix data is represented by a bit of the binary number; wherein the state of the printing dot includes on and off, corresponding to the binary numbers 1 and 0 respectively; the dot matrix data includes the printing dot value and the printing dot target grayscale value.

[0013] As a further solution of the present invention: In S01:

[0014] If the print point value is 1, a power-on signal is generated; at this time, the heating wire on the print point is controlled to remain in the on state, and the heating wire is powered on for heating;

[0015] If the printing point value is 0, a power-off signal is generated; at this time, the heating line on the printing point is controlled to be in a closed state, and the printing point is not heated.

[0016] As a further solution of the present invention: In S02, the method for obtaining the target power value Pw includes the following steps:

[0017] S021: Calculate the printing temperature value DT of the heating line through the grayscale thermal ratio model, that is, ; Where a is the temperature influence coefficient and b is the grayscale correction coefficient;

[0018] S022: Based on the printing temperature value DT, the target power value Pw of the heating line is calculated by the temperature performance model; that is, ; Where c is the thermal stability coefficient, d is the travel heat loss coefficient, and t is the printing time value, that is, the total time required for the thermal print head to complete heating and the printing.

[0019] As a further solution of the present invention: in S022, t is the sum of the heating time t1 and the print head travel time t2. Generally speaking, in order to ensure the efficiency of thermal printing, the heating time and the print head travel time are usually preset time values.

[0020] As a further solution of the present invention: the target current value ID is obtained as follows:

[0021] Get the rated resistance value RD of the heating wire by The target current value ID is calculated.

[0022] As a further solution of the present invention: after the thermal printing is completed, the printing gray value of the printing point is obtained, which is recorded as YWH;

[0023] Determine whether the printing gray value YWH of the printing point is within the printing point target gray value range [DSmin, DSmax];

[0024] If the printing gray value YWH of the printing point is within the target gray value range [DSmin, DSmax] of the printing point, a printing gray qualified signal is generated;

[0025] If the printing gray value YWH of the printing point is not within the target gray value range [DSmin, DSmax] of the printing point, a printing gray abnormality signal is generated;

[0026] Among them, DSmin is the minimum grayscale value of the printing point target, and DSmax is the maximum grayscale value of the printing point target; , , where DSy is the grayscale fluctuation threshold of the printing point.

[0027] As a further solution of the present invention: based on the printing grayscale abnormality signal, the printing grayscale value YWH is judged to obtain a printing grayscale performance difference signal or a printing grayscale excessive signal;

[0028] Specific:

[0029] If the printing grayscale value YWH is less than the minimum target grayscale value DSmin of the printing point, a printing grayscale performance difference signal is generated;

[0030] If the printing grayscale value YWH is greater than the maximum target grayscale value DSmax of the printing point, a printing grayscale over-expression signal is generated.

[0031] As a further solution of the present invention: feedback updating the grayscale thermal ratio model and the temperature performance model in the data unit based on the printing grayscale performance difference signal or the printing grayscale excessive signal;

[0032] The specific steps include:

[0033] S061: If the feedback update unit obtains a printing grayscale performance difference signal, the target current value ID is increased, thereby increasing the printing temperature value of the heating line, so that the grayscale value of the printed point on the thermal paper reaches the target grayscale value DS;

[0034] If the feedback update unit obtains a printing grayscale over-signal, the target current value ID is reduced, thereby reducing the printing temperature value of the heating line, so that the grayscale value of the printed point on the thermal paper reaches the target grayscale value DS;

[0035] S062: Mark the increased or decreased target current value as the updated current value IX; based on the updated current value IX, Calculate and obtain an updated power value Px;

[0036] At the same time, the temperature sensor is used to obtain the updated temperature value XT of the thermal print head when printing on the thermal paper;

[0037] S063: replacing the printing temperature value DT and the target power value Pw corresponding to the target gray value DS in the historical data based on the updated power value Px and the updated temperature value XT;

[0038] Then, based on the updated historical data, the updated temperature influence coefficient a1 and grayscale correction coefficient b1 are calculated to obtain the updated grayscale thermal ratio model, namely: ;

[0039] Finally, based on the updated historical data, the updated thermal stability coefficient c1 and the travel heat loss coefficient d1 are calculated to obtain the updated temperature performance model. .

[0040] As a further solution of the present invention: a thermal film printing device, comprising a thermal film cable, a thermal film, a rubber belt, a rotating shaft and a pressing plate;

[0041] Rotating shafts are symmetrically arranged inside the rubber belt, and pressure plates are arranged inside the two rotating shafts. A thermal sheet is arranged below the pressure plates, and one side of the thermal sheet is electrically connected to the thermal sheet wiring.

[0042] Beneficial effects of the present invention:

[0043] By processing the data information to be printed, processing the data information into binary data, matching the dot matrix data in the font library based on the data to be printed, processing the gray value of the data information based on the dot matrix data, and calculating the target current value of the corresponding heating line on the printing point based on the constructed gray thermal ratio model and temperature performance model, and then controlling the current of the heating line through the electronic control unit to adjust the temperature of the heating line to the target temperature, and then printing the data on the thermal printing paper, accurately and effectively realizing the temperature control, ensuring that the gray scale of the thermally printed data meets the requirements; ensuring that the problem of unqualified printing gray scale occurs in the thermal printing process and the multi-point printing process, and improving the recognition of the printed data;

[0044] At the same time, after the thermal printing is completed, the grayscale value of the printed data is detected to determine whether the grayscale value of the printed data meets the requirements. When the grayscale value of the printed data does not meet the requirements, the target current value of the heating line is adjusted, and then the grayscale thermal ratio model and the temperature performance model are updated to ensure that in the subsequent printing process, the grayscale value of the printed data is more accurate, thereby improving the accuracy of thermal printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention will be further described below in conjunction with the accompanying drawings.

[0046] Figure 1 It is a schematic flow chart of the printing method of the present invention;

[0047] Figure 2 It is a schematic diagram of the process of controlling the current of the heating wire in the present invention;

[0048] Figure 3 is a schematic diagram of a printing device in the present invention;

[0049] In the figure: 1. Thermal sheet cable; 2. Thermal sheet; 3. Rubber belt; 4. Rotating shaft; 5. Thermal paper; 6. Pressing plate. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0051] See also Figure 1 - Figure 2 As shown, the present invention is a thermal sheet printing method, comprising:

[0052] Step 1: Obtain data information to be printed, the data information to be printed includes text data information; convert the text data information into binary data, and then convert the binary data into hexadecimal byte data through encoding;

[0053] Step 2: After receiving the byte data from the data acquisition module, the corresponding dot matrix data is searched in the built-in character library of the printing system according to the content of the byte data;

[0054] The dot matrix data is a set of binary numbers that describe character data. The state of each printing dot in the dot matrix data is represented by a bit of a binary number. The states of the printing dot include on and off, which correspond to 1 and 0 of the binary number respectively. The dot matrix data includes the printing dot value and the printing dot target grayscale value.

[0055] Step 3: Obtain dot matrix data, and based on the dot matrix data, control the current of the heating line corresponding to each printing point on the thermal sheet, burn on the thermal paper to complete the printing of data information;

[0056] The specific process of current control of the heating wire includes:

[0057] S01: Obtain the printing point value of each printing point in the dot matrix data;

[0058] If the print point value is 1, a power-on signal is generated; at this time, the heating wire on the print point is controlled to remain in the on state, and the heating wire is powered on for heating;

[0059] If the print point value is 0, a power-off signal is generated; at this time, the heating line on the print point is controlled to be in a closed state, and the print point is not heated;

[0060] S02: based on the power-on signal, obtaining a target grayscale value of the printing point, and recording the target grayscale value of the printing point as DS, and calculating a target power value Pw of the heating line on the printing point based on the target grayscale value DS of the printing point;

[0061] The following steps are involved:

[0062] S021: Calculate the printing temperature value DT of the heating line through the grayscale thermal ratio model, that is, ; Where a is the temperature influence coefficient and b is the grayscale correction coefficient;

[0063] S022: Based on the printing temperature value DT, the target power value Pw of the heating line is calculated by the temperature performance model; that is, ; Where c is the thermal stability coefficient, d is the travel heat loss coefficient, and t is the printing time value, that is, the total time required for the thermal print head to complete heating and the printing;

[0064] Specifically, t is the sum of the heating time t1 and the print head travel time t2. Generally speaking, in order to ensure the efficiency of thermal printing, the heating time and the print head travel time are usually preset time values;

[0065] It should be noted that the grayscale thermal ratio model is trained based on a large amount of printing temperature data and printing grayscale data;

[0066] The temperature performance value is also obtained through training based on a large amount of printing temperature data and printing power data;

[0067] S03: Obtain a target power value Pw, and based on the target power value Pw, control and adjust the current value of the heating line to reach the target current value ID, so that the power value of the heating line is adjusted to the target power value Pw; at this time, control the thermal print head to heat, maintain the heating time t1, and then perform thermal printing;

[0068] The target current value ID is obtained as follows:

[0069] Get the rated resistance value RD of the heating wire by Calculate the target current value ID;

[0070] S04: After the thermal printing is completed, the printing grayscale value of the printing point is obtained, which is recorded as YWH;

[0071] Determine whether the printing gray value YWH of the printing point is within the printing point target gray value range [DSmin, DSmax];

[0072] If the printing gray value YWH of the printing point is within the target gray value range [DSmin, DSmax] of the printing point, a printing gray qualified signal is generated;

[0073] If the printing gray value YWH of the printing point is not within the target gray value range [DSmin, DSmax] of the printing point, a printing gray abnormality signal is generated;

[0074] It should be noted that DSmin is the minimum grayscale value of the printing point target, and DSmax is the maximum grayscale value of the printing point target; , , where DSy is the grayscale fluctuation threshold of the printing point;

[0075] S05: Based on the abnormal printing grayscale signal, the printing grayscale value YWH is judged to obtain a poor printing grayscale performance signal or a excessive printing grayscale signal;

[0076] Specific:

[0077] If the printing grayscale value YWH is less than the minimum target grayscale value DSmin of the printing point, a printing grayscale performance difference signal is generated;

[0078] If the printing grayscale value YWH is greater than the maximum grayscale value DSmax of the printing point target, a printing grayscale over-performance signal is generated;

[0079] S06: Feedback and update the grayscale thermal ratio model and the temperature performance model in the data unit based on the poor grayscale performance signal or the excessive grayscale performance signal;

[0080] The specific steps include:

[0081] S061: If the feedback update unit obtains a printing grayscale performance difference signal, the target current value ID is increased, thereby increasing the printing temperature value of the heating line, so that the grayscale value of the printed point on the thermal paper reaches the target grayscale value DS;

[0082] If the feedback update unit obtains a printing grayscale over-signal, the target current value ID is reduced, thereby reducing the printing temperature value of the heating line, so that the grayscale value of the printed point on the thermal paper reaches the target grayscale value DS;

[0083] S062: Mark the increased or decreased target current value as the updated current value IX; based on the updated current value IX, Calculate and obtain an updated power value Px;

[0084] At the same time, the temperature sensor is used to obtain the updated temperature value XT of the thermal print head when printing on the thermal paper;

[0085] S063: replacing the printing temperature value DT and the target power value Pw corresponding to the target gray value DS in the historical data based on the updated power value Px and the updated temperature value XT;

[0086] Then, based on the updated historical data, the updated temperature influence coefficient a1 and grayscale correction coefficient b1 are calculated to obtain the updated grayscale thermal ratio model, namely: ;

[0087] Finally, based on the updated historical data, the updated thermal stability coefficient c1 and the travel heat loss coefficient d1 are calculated to obtain the updated temperature performance model. .

[0088] By processing the data information to be printed, processing the data information into binary data, matching the dot matrix data in the font library based on the data to be printed, processing the gray value of the data information based on the dot matrix data, and calculating the target current value of the corresponding heating line on the printing point based on the constructed gray thermal ratio model and temperature performance model, and then controlling the current of the heating line through the electronic control unit to adjust the temperature of the heating line to the target temperature, and then printing the data on the thermal printing paper, accurately and effectively realizing the temperature control, ensuring that the gray scale of the thermally printed data meets the requirements; ensuring that the problem of unqualified printing gray scale occurs in the thermal printing process and the multi-point printing process, and improving the recognition of the printed data;

[0089] At the same time, after the thermal printing is completed, the grayscale value of the printed data is detected to determine whether the grayscale value of the printed data meets the requirements. When the grayscale value of the printed data does not meet the requirements, the target current value of the heating line is adjusted, and then the grayscale thermal ratio model and the temperature performance model are updated to ensure that in the subsequent printing process, the grayscale value of the printed data is more accurate, thereby improving the accuracy of thermal printing. Embodiment 2

[0090] Based on the above embodiment, in S061 of this embodiment, based on the poor grayscale performance signal or the excessive grayscale performance signal, the target current value is increased or decreased respectively to increase or decrease the printing temperature value of the heating line, and the thermal paper is printed again;

[0091] Specifically, when a signal indicating poor grayscale performance is obtained, the process of adjusting the target current value and printing the thermal paper again is as follows:

[0092] W1: Based on the print grayscale performance difference signal, the target current value is increased by the unit current adjustment value TTI, and the current increase adjustment value TTIn is obtained; at this time ;

[0093] Then adjust to TTIn based on the current increase, by Calculate and obtain the power increase adjustment value Pn;

[0094] W2: Printing on thermal paper based on the current increase adjustment value TTIn, and obtaining the temperature increase adjustment value XTn during the printing process;

[0095] W3: After printing is completed, the print point elevation is obtained to adjust the print grayscale value YWn;

[0096] Determine whether the raised adjusted printing gray value YWn of the printing dot is within the target gray value range [DSmin, DSmax] of the printing dot;

[0097] If the print gray value YWn adjusted by the print dot elevation is within the print dot target gray value range [DSmin, DSmax], a print gray qualified signal is generated;

[0098] If the grayscale value YWn adjusted by the printing dot is not within the target grayscale value range [DSmin, DSmax] of the printing dot, a grayscale abnormality signal is generated; at this time, the grayscale value YWn is adjusted to be judged, and a grayscale performance difference signal or a grayscale over-performance signal is obtained; then the adjustment is continued;

[0099] W4: If a qualified printing grayscale signal is obtained, the current increase adjustment value TTIn is recorded as the updated current value IX; the power increase adjustment value Pn is recorded as the updated power value Px.

[0100] Specifically, when a printing grayscale transition signal is obtained, the process of adjusting the target current value and printing the thermal paper again is as follows:

[0101] M1: based on the printing grayscale performance difference signal, the target current value is reduced by the unit current adjustment value TTI, and the current increase adjustment value TTIu is obtained; at this time ;

[0102] Then adjust to TTIu based on the current reduction, by Calculate and obtain the power reduction adjustment value Pu;

[0103] M2: Printing on thermal paper based on the current reduction adjustment value TTIu, and obtaining the temperature reduction adjustment value XTu during the printing process;

[0104] M3: After printing is completed, obtain the lowering and adjusting printing grayscale value YWu of the printing point;

[0105] Determine whether the lowered adjusted printing grayscale value YWu of the printing point is within the target grayscale value range [DSmin, DSmax] of the printing point;

[0106] If the print gray value YWu adjusted by the reduction of the print point is within the print point target gray value range [DSmin, DSmax], a print gray qualified signal is generated;

[0107] If the grayscale value YWu adjusted by the reduction of the printing point is not within the target grayscale value range [DSmin, DSmax] of the printing point, a grayscale abnormality signal is generated; at this time, the grayscale value YWn is adjusted to be judged, and a grayscale performance difference signal or a grayscale over-performance signal is obtained; then the adjustment is continued;

[0108] M4: If a printing grayscale qualified signal is obtained, the current reduction adjustment value TTIu is recorded as the updated current value IX; the power reduction adjustment value Pu is recorded as the updated power value Px.

[0109] The electric control unit controls the current of the heating wire so that the temperature of the heating wire is adjusted to the target temperature, and then the data is printed on the thermal printing paper, and the temperature control is accurately and effectively realized. When the printing grayscale value is unqualified, the printing current value is self-adjusted, and the printing power value is further adjusted to ensure that the grayscale of the thermally printed data meets the requirements; it ensures that the problem of unqualified printing grayscale occurs during the thermal printing process and the multi-point printing process, and the purpose of self-regulation is achieved, and the printing is adjusted quickly. Embodiment 3

[0110] Based on the above embodiment, this embodiment provides a thermal film printing system, which is used to execute the printing method of the above embodiment 1, including:

[0111] Data acquisition module: The data acquisition module is used to obtain the printing point value of each printing point in the dot matrix data; judge and obtain the power-on signal;

[0112] Data processing module: The data processing module obtains the target grayscale value of the printing point based on the power-on signal, and records the target grayscale value of the printing point as DS. Based on the target grayscale value DS of the printing point, the target power value Pw of the heating line on the printing point is calculated;

[0113] Print execution module: The print execution module is used to obtain the target power value Pw, and based on the target power value Pw, control and adjust the current value of the heating line to reach the target current value ID, so that the power value of the heating line is adjusted to the target power value Pw; at this time, control the thermal print head to heat, maintain the heating time t1, and then perform thermal printing;

[0114] Data information to be printed is processed, data information is processed in binary form, and dot matrix data in the font is matched based on the data to be printed, grayscale value of the data information is processed based on the dot matrix data, and the target current value of the corresponding heating line on the printing point is calculated based on the constructed grayscale thermal ratio model and temperature performance model, and then the current of the heating line is controlled by the electronic control unit to adjust the temperature of the heating line to the target temperature, and then data is printed on the thermal printing paper, and temperature control is achieved accurately and effectively to ensure that the grayscale of the thermally printed data meets the requirements; it ensures that the problem of unqualified printing grayscale occurs during thermal printing and multi-point printing, and improves the recognition of printed data. Embodiment 4

[0115] Reference Figure 3 As shown, a thermal film printing device includes: a thermal film cable 1, a thermal film 2, a rubber belt 3, a rotating shaft 4 and a pressing plate 6;

[0116] The rubber belt 3 is symmetrically provided with a rotating shaft 4, and the two rotating shafts 4 are provided with a pressing plate 6 inside. A thermal sheet 2 is provided below the pressing plate 6, and one side of the thermal sheet 2 is electrically connected to the thermal sheet cable 1. The device is used to perform the printing method in the above-mentioned embodiment 1;

[0117] During use, the thermal paper 5 passes between the pressing plate 6 and the thermal sheet 2 .

[0118] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A thermal film printing method, characterized in that: include: Step 1: Obtain data information to be printed, the data information to be printed includes text data information; convert the text data information into hexadecimal byte data; Step 2: After receiving the byte data from the data acquisition module, the corresponding dot matrix data is searched in the built-in character library of the printing system according to the content of the byte data; In the step 2, the dot matrix data is a set of binary numbers describing the character data, and the state of each printing dot in the dot matrix data is represented by a bit of the binary number; wherein the state of the printing dot includes on and off, corresponding to 1 and 0 of the binary number respectively; the dot matrix data includes the printing dot value and the printing dot target gray value; Step 3: Obtain dot matrix data, and based on the dot matrix data, control the current of the heating line corresponding to each printing point on the thermal sheet, burn on the thermal paper to complete the printing of data information; including: S01: Obtain the printing point value of each printing point in the dot matrix data; determine and obtain the power-on signal; In the S01: If the print point value is 1, a power-on signal is generated; at this time, the heating wire on the print point is controlled to remain in the on state, and the heating wire is powered on for heating; If the print point value is 0, a power-off signal is generated; at this time, the heating line on the print point is controlled to be in a closed state, and the print point is not heated; S02: based on the power-on signal, obtaining a target grayscale value of the printing point, and recording the target grayscale value of the printing point as DS, and calculating a target power value Pw of the heating line on the printing point based on the target grayscale value DS of the printing point; In S02, the method for obtaining the target power value Pw includes the following steps: S021: Calculate the printing temperature value DT of the heating line through the grayscale thermal ratio model, that is, ; Where a is the temperature influence coefficient and b is the grayscale correction coefficient; S022: Based on the printing temperature value DT, the target power value Pw of the heating line is calculated by the temperature performance model; that is, ; Where c is the thermal stability coefficient, d is the travel heat loss coefficient, and t is the printing time value, that is, the total time required for the thermal print head to complete heating and the printing; S03: Obtain the target power value Pw, and based on the target power value Pw, control and adjust the current value of the heating line to reach the target current value ID, so that the power value of the heating line is adjusted to the target power value Pw; at this time, control the thermal print head to heat, maintain the heating time t1, and then perform thermal printing.

2. A thermal film printing method according to claim 1, characterized in that: In the above S022, t is the sum of the heating time t1 and the print head travel time t2.

3. A thermal film printing method according to claim 1, characterized in that: The target current value ID is obtained as follows: Get the rated resistance value RD of the heating wire by The target current value ID is calculated.

4. A thermal film printing method according to claim 1, characterized in that: After thermal printing is completed, the printing grayscale value of the printing point is obtained, which is recorded as YWH; Determine whether the printing gray value YWH of the printing point is within the printing point target gray value range [DSmin, DSmax]; If the printing gray value YWH of the printing point is within the target gray value range [DSmin, DSmax] of the printing point, a printing gray qualified signal is generated; If the printing gray value YWH of the printing point is not within the target gray value range [DSmin, DSmax] of the printing point, a printing gray abnormality signal is generated; Among them, DSmin is the minimum grayscale value of the printing point target, and DSmax is the maximum grayscale value of the printing point target; , , where DSy is the grayscale fluctuation threshold of the printing point.

5. A thermal film printing method according to claim 4, characterized in that: Based on the abnormal printing grayscale signal, the printing grayscale value YWH is judged to obtain a poor printing grayscale performance signal or an excessive printing grayscale signal; Specific: If the printing grayscale value YWH is less than the minimum target grayscale value DSmin of the printing point, a printing grayscale performance difference signal is generated; If the printing grayscale value YWH is greater than the maximum target grayscale value DSmax of the printing point, a printing grayscale over-expression signal is generated.

6. A thermal film printing method according to claim 5, characterized in that: Feedback updating of the grayscale thermal ratio model and the temperature performance model in the data unit based on the poor grayscale performance signal or the excessive grayscale performance signal; The specific steps include: S061: If the feedback update unit obtains a printing grayscale performance difference signal, the target current value ID is increased, thereby increasing the printing temperature value of the heating line, so that the grayscale value of the printed point on the thermal paper reaches the target grayscale value DS; If the feedback update unit obtains a printing grayscale over-signal, the target current value ID is reduced, thereby reducing the printing temperature value of the heating line, so that the grayscale value of the printed point on the thermal paper reaches the target grayscale value DS; S062: Mark the increased or decreased target current value as the updated current value IX; based on the updated current value IX, Calculate and obtain an updated power value Px; At the same time, the temperature sensor is used to obtain the updated temperature value XT of the thermal print head when printing on the thermal paper; S063: replacing the printing temperature value DT and the target power value Pw corresponding to the target gray value DS in the historical data based on the updated power value Px and the updated temperature value XT; Then, based on the updated historical data, the updated temperature influence coefficient a1 and grayscale correction coefficient b1 are calculated to obtain the updated grayscale thermal ratio model, namely: ; Finally, based on the updated historical data, the updated thermal stability coefficient c1 and the travel heat loss coefficient d1 are calculated to obtain the updated temperature performance model. .

7. A thermal film printing device, characterized in that: It comprises a thermal sheet cable (1), a thermal sheet (2), a rubber belt (3), a rotating shaft (4) and a pressing plate (6); Rotating shafts (4) are symmetrically arranged inside the rubber belt (3), pressing plates (6) are arranged inside the two rotating shafts (4), a thermal sheet (2) is arranged below the pressing plates (6), and one side of the thermal sheet (2) is electrically connected to the thermal sheet cable (1); The device is used to execute the printing method described in any one of claims 1 to 6.

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