Roller type unidirectional rotation scanning printing method and roller type scanning printing device

Abstract

The present invention belongs to the technical field of inkjet printing, and in particular, relates to a roller-type unidirectional rotation scanning printing method and a roller-type scanning printing device. The method of the present invention comprises the following steps: obtaining the number of times the print head moves along the axial direction of the printing roller after the printing starts, the distance of each movement, and the target number of rotations of the printing roller determined by the printing requirements; obtaining the printing data of the image to be printed; dividing the printing data into a number of sub-printing data according to the number of times the print head moves along the axial direction of the printing roller and the distance of each movement; controlling the unidirectional rotation of the printing roller, and controlling the print head to print the sub-printing data one by one according to the position of the print head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller, and each time the printing of a sub-printing data is completed, the print head moves once along the axial direction of the printing roller until all the sub-printing data are printed. The present invention can take into account both printing accuracy and production capacity.

Description

Technical Field

[0001] The invention relates to the technical field of inkjet printing, and in particular to a roller-type unidirectional rotation scanning printing method and a roller-type scanning printing device. Background Art

[0002] At present, digital inkjet printing mostly adopts scanning printing. In scanning printing, the print head is equivalent to the moving direction of the printing medium, which mainly has scanning direction and stepping direction. The scanning direction is the X direction. Each time the print head scans, the corresponding ink width is sprayed according to the width of the data stripe, and a line of data stripe is printed on the substrate. After a line of data stripe is printed, the width of the next data stripe is displaced in the Y direction by the stepping direction, so as to realize line-by-line scanning. In this way, through multiple scanning and stepping, the printing of the entire image is realized. In the current scanning printing, since the X direction needs to work back and forth many times, and the X direction must be relatively parallel to the substrate, the existing printers often greatly reduce the printing effect because the two are not parallel enough. At the same time, when stepping in the Y direction, due to insufficient stepping accuracy, ink dot displacement will occur when the XY data is orthogonal, resulting in reduced accuracy.

[0003] In the aforementioned printing method, the scanning in the X direction is divided into unidirectional scanning and bidirectional scanning. Among them, unidirectional scanning is also called one-way scanning, that is, inkjet printing is performed in the outbound process of the X direction, but no inkjet is performed in the return process. Compared with bidirectional scanning, unidirectional scanning avoids the problem of double registration during bidirectional printing, and the printed products are more accurate and have better effects. However, since inkjet printing is not performed during the return process, the printing efficiency is not high, resulting in low production capacity of the printing equipment. Among them, bidirectional scanning not only performs inkjet printing in the outbound process, but also in the return process, so the printing efficiency is high and the production capacity of the printing equipment is correspondingly high. However, for bidirectional scanning, during the scanning and printing process, the object to be printed is in a stationary state, and the nozzle must move linearly along the X direction and return to the starting point. During the high-speed movement of the nozzle and when the nozzle stops and returns, the ink in the ink storage box above the nozzle and the ink tube connected to the ink box will produce a large surge, which changes the pressure inside the ink box and reduces the stability of the printing work. In addition, bidirectional scanning requires two registrations, so the printing accuracy is not high. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a roller-type unidirectional rotation scanning and printing method and a roller-type scanning and printing device, which are used to solve the technical problem that the existing scanning and printing technology cannot take into account both printing accuracy and production capacity.

[0005] The technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a roller-type unidirectional rotating scanning printing method, wherein a printing medium for printing is coated on the outer circumferential surface of a printing roller, and the method comprises the following steps:

[0007] Obtaining the number of times the print head moves along the axial direction of the printing roller after printing starts, the distance of each movement, and the target number of rotations of the printing roller determined by the printing requirements;

[0008] Acquire printing data of the image to be printed;

[0009] Dividing the print data into a number of sub-print data according to the number of times the print head moves along the axial direction of the printing roller and the distance of each movement, wherein the number of sub-print data is the same as the number of times the print head moves along the axial direction of the printing roller;

[0010] The printing roller is controlled to rotate unidirectionally, and during the unidirectional rotation of the printing roller, the printing head is controlled to print the sub-printing data one by one according to the position of the printing head in the circumferential direction of the printing roller. Each time a sub-printing data is printed, the printing head moves once along the axial direction of the printing roller until all the sub-printing data are printed.

[0011] Preferably, the printing roller is controlled to rotate unidirectionally, and during the unidirectional rotation of the printing roller, the print head is controlled to print the sub-print data one by one according to the position of the print head in the circumferential direction of the printing roller. Each time a sub-print data is printed, the print head moves once along the axial direction of the printing roller until all the sub-print data are printed.

[0012] S41: Obtaining the number of times the current print head moves along the axial direction of the printing roller;

[0013] S42: acquiring sub-printing data corresponding to the number of movement times according to the number of movement times;

[0014] S43: controlling the printing roller to rotate unidirectionally for one circle, and controlling the printing head to print the corresponding sub-printing data according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation;

[0015] S44: After the corresponding sub-printing data is printed, the printing medium is solidified, and the printing head is controlled to move once in the axial direction of the printing roller before the next sub-printing data starts to be printed;

[0016] S45: Repeat the above steps S41 to S45 until all sub-print data are printed.

[0017] Preferably, the step S43: controlling the printing roller to rotate one circle in one direction, and controlling the printing head to print the corresponding sub-printing data according to the position of the printing head in the circumferential direction of the printing roller during the one circle rotation includes the following steps:

[0018] Perform edge detection of printing media during unidirectional rotation of the printing roller;

[0019] The position of the printing head in the circumferential direction of the printing roller when the edge of the printing medium is detected is used as the starting point of printing the corresponding sub-printing data;

[0020] The real-time position of the printing roller is acquired through an encoder tangent to the printing roller or a grating size installed on the surface of the roller, and the print head is controlled to print the print data corresponding to the real-time position in the sub-print data.

[0021] Preferably, the step of determining the position of the print head in the circumferential direction of the printing roller according to the arc length of the printing roller in the circumferential direction rotated from the starting position further comprises the following steps:

[0022] Obtaining a rotation angle of a rotary encoder that rotates synchronously with the encoding wheel from the starting position, wherein the outer circumference of the encoding wheel is tangent to the outer circumference of the printing roller;

[0023] Get the diameter of the code wheel;

[0024] Determine the arc length of the outer surface rotation of the code wheel according to the rotation angle of the rotary encoder and the diameter of the code wheel;

[0025] The position of the print head in the circumferential direction of the printing roller is determined according to the diameter of the outer circumferential surface of the printing roller and the arc length of the outer circumferential surface of the encoding wheel.

[0026] Preferably, the method of controlling the printing roller to rotate unidirectionally and controlling the printing head to print the sub-print data one by one according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller, and each time the printing of a sub-print data is completed, the printing head moves once along the axial direction of the printing roller until all the sub-print data are completed and printed, further comprises the following steps:

[0027] When the printed medium is transported to the drying station, it enters the drying and curing stage, which includes the following steps:

[0028] Get the preset drying time;

[0029] Obtaining the amount of printing ink of an image printed on a printing medium;

[0030] Determining a drying temperature for drying the print medium according to the amount of print ink of the image and a preset drying time;

[0031] Controlling the drying device to dry the printing medium at the drying temperature;

[0032] Get the preset curing time;

[0033] Determining a curing power for curing the print medium according to the amount of printed ink of the image and a preset curing time;

[0034] The curing device is controlled to perform a curing process on the printing medium with the curing power.

[0035] Preferably, the method further comprises the following steps:

[0036] Detect whether the printing carriage is in the printing area;

[0037] When it is detected that the printing carriage is in the printing area, the surface height of the printing medium is detected;

[0038] When the height of the printing medium surface is detected to exceed a preset height, a printing medium abnormality trigger signal is generated;

[0039] When an abnormal trigger signal of the printing medium is detected, the inkjet signal output to the printing nozzle is stopped, and the nozzle is controlled to move in a direction away from the printing roller.

[0040] Preferably, when a printing medium abnormality trigger signal is detected, the method further includes the following steps:

[0041] Determine whether there is printing medium in the current drying station;

[0042] If yes, the printing roller is controlled to drive the printing medium to continue rotating with the printing roller;

[0043] Otherwise, the printed media on the printing roller is transported to the drying station.

[0044] Preferably, a plurality of air suction holes are provided on the outer circumferential surface of the printing roller. In the step S4: controlling the printing roller to rotate unidirectionally, and controlling the printing head to print the sub-printing data one by one according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller, each time a sub-printing data is printed, the printing head moves once along the axial direction of the printing roller until all the sub-printing data are printed and then enters the printing medium roller discharge stage, and the printing medium roller discharge stage includes the following steps:

[0045] The outer circumferential surface of the printing roller is divided into a plurality of adsorption areas along the circumferential direction, and the air suction holes contained in each adsorption area are determined;

[0046] Get the current angular position of the printing roller;

[0047] Determine the distance between each adsorption area on the outer cylindrical surface of the printing roller and the next link according to the current rotational angular position of the printing roller;

[0048] The suction force and / or switching of the suction holes of each adsorption area are controlled according to the distance between each adsorption area and the next link.

[0049] Preferably, the nozzles of the printing head are all oriented toward the center of the roller, and the plane where the nozzles in the same row of the printing head are located is parallel to the axis of the printing roller.

[0050] In a second aspect, the present invention further provides a drum-type scanning printing device, comprising a printing roller, a first driving mechanism, a print head and a control circuit, wherein the first driving mechanism is used to drive the printing roller to rotate, the control circuit is electrically connected to the print head and the first driving mechanism, the control circuit comprises at least one processor, at least one memory and computer program instructions stored in the memory, and when the computer program instructions are executed by the processor, the method described in any one of claims 1 to 9 is implemented

[0051] Beneficial effects: The roller-type unidirectional rotation scanning printing method and the roller-type scanning printing device of the present invention cleverly utilize the principle that the roller rotates along the center of a circle, that is, the starting point and the end point are at the same position after the roller rotates one circle, thereby realizing an efficient and high-speed single-pass printing mode. The present invention performs scanning and printing during the unidirectional rotation of the printing roller, thereby avoiding the linear reciprocating scanning stroke during the printing process. The unidirectional rotation of the printing roller allows the printing process to maintain the printing scanning state consistently, thereby obtaining the same printing accuracy as the unidirectional scanning. Since the printing roller can periodically return to the position at the beginning of printing during the unidirectional rotation, and the printing head can keep printing during the rotation of the printing roller without waiting for the return time, it has a high printing efficiency, thereby significantly improving the production capacity of the printing device. In addition, during the printing process, the printing head moves along the axial direction of the printing roller, so that the printing head can always maintain a relative tangent point position with respect to the outer cylindrical surface of the printing medium, thereby avoiding the situation that the two planes in the existing scanning printing are not parallel enough, and the plane-to-plane parallelism is changed to point-to-point parallelism, thereby further improving the accuracy in printing. During the printing process, the print head moves along the axial direction of the printing roller to achieve stepping, and the outer cylindrical surface of the printing roller always rotates around the axis, which greatly improves the orthogonal accuracy of the scanning direction and the stepping direction, thereby further improving the printing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for use in the embodiment of the present invention will be briefly introduced below. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work, and these are all within the protection scope of the present invention.

[0053] Figure 1 It is a schematic diagram of the process flow of the roller-type unidirectional rotation scanning printing method of the present invention;

[0054] Figure 2 It is a schematic flow chart of a method for printing during unidirectional rotation of a printing roller according to the present invention;

[0055] Figure 3 It is a schematic flow chart of a printing method in which the printing roller of the present invention rotates one circle in one direction;

[0056] Figure 4 It is a schematic flow chart of the method for obtaining the circumferential position of the printing roller of the present invention;

[0057] Figure 5 It is a schematic diagram of a flow chart of a method for drying a printing medium according to the present invention;

[0058] Figure 6 A schematic diagram of the flow of a method for detecting warping of a printing medium according to the present invention;

[0059] Figure 7 It is a flow chart of a method for controlling the conveyance of printing media according to the conditions of a drying station of the present invention;

[0060] Figure 8 It is a schematic flow chart of the method for controlling the adsorption holes of the printing roller in sections of the present invention;

[0061] Fig. 9 A detailed schematic diagram of the printing method of the present invention;

[0062] Fig.10 It is a structural schematic diagram of the drum type scanning and printing device of the present invention;

[0063] Fig.11 It is a structural schematic diagram of a drum-type scanning and printing device with a feeding mechanism of the present invention;

[0064] Feeder 1, feeding device 2, feed buffer 3, feed bridge 4, printing roller 5, servo motor 6, print nozzle 7, rotary encoder 8, print drying box 9, discharge bridge 10, discharge buffer 11, material receiver 12, printing medium 13. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described in conjunction with the drawings in the embodiment of the present invention. It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or device. In the absence of further restrictions, the elements defined by the phrase "comprising..." do not exclude the existence of other identical elements in the process, method, article or device comprising the elements. If there is no conflict, the embodiments of the present invention and the various features in the embodiments can be combined with each other, all within the protection scope of the present invention.

[0066] Example 1

[0067] like Figure 1 As shown, this embodiment provides a roller-type unidirectional rotation scanning printing method, in which a printing medium 13 is coated on the outer circumferential surface of a printing roller 5, and the method comprises the following steps:

[0068] S1: Obtaining the number of times the print head 7 moves along the axial direction of the printing roller 5, the distance of each movement, and the target number of rotations of the printing roller 5 determined by the printing requirements;

[0069] The printing requirements include the printing size requirements, printing time requirements and printing accuracy requirements. The shorter the printing time requirement, the fewer times the print head 7 scans along the circumferential direction of the printing roller 5.

[0070] That is, the number of times the print head 7 moves along the axial direction of the printing roller 5 is small. If the printing accuracy requirement is high, the number of times the print head 7 scans along the circumferential direction of the printing roller 5 is large, that is, the number of times the print head 7 moves along the axial direction of the printing roller 5 is large, and the moving distance is short. Under the condition of the same printing accuracy and printing time, the larger the size along the axial direction of the printing roller 5 in the printing size requirement, the more times the printing roller 5 moves. Therefore, the number of times the print head 7 moves along the axial direction of the printing roller 5 and the distance of each movement can be set based on experience in combination with the printing accuracy and printing time requirements. For the convenience of control, the distance of each movement can be set to be the same, and of course different moving distances can be used. Ideally, the printing roller 5 completes a scan and print once for each rotation, and the print head 7 moves once in the axial direction. Therefore, when the number of times the print head 7 moves along the axial direction of the printing roller 5 is determined, the number of turns that the printing roller 5 needs to rotate in order to complete the printing task, that is, the target number of turns of the printing roller 5, can also be determined in an ideal situation.

[0071] S2: Get print data;

[0072] The printing device obtains the printing data from the corresponding printing file according to the printing task. The printing image is composed of pixels arranged in a matrix. Each pixel has its corresponding printing data, and the printing data corresponding to all pixels constitute the complete printing data in the printing file. The printing data includes the position of the corresponding pixel, the number of ink dots printed for the pixel, the ink dot size, the ink dot position and other information.

[0073] S3: dividing the print data into a number of sub-print data according to the number of times the print head 7 moves along the axial direction of the printing roller 5 and the distance of each movement, wherein the number of sub-print data is the same as the number of times the print head 7 moves along the axial direction of the printing roller 5;

[0074] There is a corresponding relationship between the sub-printing data and the number of movement of the print head 7. When printing starts, the number of movement of the first print head along the axial direction of the printing roller 5 is 0, and the number of movement of the print head 7 increases by 1 each time the print head 7 moves along the axial direction of the printing roller 5. The sub-first data of the first print corresponds to the number of movement 0, the sub-printing data of the second print corresponds to the number of movement 1, and so on, and the sub-printing data of the nth print corresponds to the number of movement n-1.

[0075] The distance that the print head 7 moves each time determines the width of the printed image covered by the print head 7 scanning one circle (i.e., the size of the printed image in the axial direction of the printing roller 5). The pixels of the image printed by the print head 7 scanning one circle can be obtained according to the width of the printed image covered by the print head 7 scanning one circle, and the corresponding data printed by the print head 7 scanning one circle can be obtained according to these pixels. The data printed by the print head 7 scanning one circle is used as a sub-printing data. All sub-printing data can be combined into complete printing data.

[0076] S4: Control the printing roller 5 to rotate unidirectionally, and during the unidirectional rotation of the printing roller 5, control the printing nozzle 7 to print the sub-printing data one by one according to the position of the printing nozzle 7 in the circumferential direction of the printing roller 5, and each time the printing of a sub-printing data is completed, the printing nozzle 7 moves once along the axial direction of the printing roller 5 until all the sub-printing data are printed.

[0077] When the printing parameters such as the number of times and distance of the nozzle movement are determined, the nozzle can be controlled to print during the rotation of the printing roller 5. During the printing of each portion of print data, the nozzle can remain stationary while the printing roller 5 rotates in one direction. For each rotation of the printing roller 5, the nozzle scans one circle relative to the printing roller 5 along the circumferential direction of the outer surface of the printing roller 5. Figure 2 As shown, the specific steps of printing in this embodiment are:

[0078] S41: Obtaining the number of times the current print head 7 moves along the axial direction of the printing roller 5;

[0079] The current movement times of the print head 7 along the axial direction of the printing roller 5 refers to the total number of times the print head 7 has moved so far.

[0080] S42: acquiring sub-printing data corresponding to the number of movement times according to the number of movement times;

[0081] S43: controlling the printing roller 5 to rotate unidirectionally for one circle, and controlling the printing head 7 to print the corresponding sub-printing data according to the position of the printing head 7 in the circumferential direction of the printing roller 5 during the unidirectional rotation;

[0082] Each time the printing roller 5 rotates one circle, the first nozzle scans once along the circumferential direction of the outer circumferential surface of the printing roller 5 and prints a sub-printing data. After the previous sub-printing data is printed, the printing roller 5 continues to rotate along the same rotation direction as the previous circle and prints the next sub-first data.

[0083] S44: After the corresponding sub-printing data is printed, the printing medium is solidified, and the printing head is controlled to move once in the axial direction of the printing roller before the next sub-printing data starts printing;

[0084] When the last print data is printed, the print medium is immediately cured so that the ink on the print medium can be firmly attached to the print medium. The curing power is determined by the amount of printed ink and the speed of the printing roller. The higher the amount of printed ink, the higher the curing power, and vice versa. The higher the speed of the printing roller, the higher the curing power, and vice versa.

[0085] The print head 7 can move once along the axial direction of the printing roller 5 to complete one step.

[0086] S45: Repeat the above steps until all sub-print data are printed.

[0087] When the print head 7 moves into position, the printing roller 5 continues to rotate to complete the printing of the next sub-print data, and the sub-print data are printed one by one in the above-mentioned manner until the last sub-print data is printed. At this time, the printing roller 5 also rotates the target number of revolutions.

[0088] like Figure 3 As shown, as an optional but advantageous real-time method, in this embodiment, the step S43: controlling the printing roller 5 to rotate one circle in one direction, and controlling the printing head 7 to print the corresponding sub-printing data according to the position of the printing head 7 in the circumferential direction of the printing roller 5 during the one-way rotation includes the following steps:

[0089] S431: Detecting the edge of the printing medium 13 during the unidirectional rotation of the printing roller 5;

[0090] In specific implementation, a paper edge detection sensor can be used to detect the edge of the printing medium 13. When the printing medium 13 rotates with the printing roller 5 until its edge is detected by the paper edge detection sensor, the paper edge detection sensor immediately generates a trigger signal. When the trigger signal is generated for the first time, it is determined to have entered the printing area, and the printing action is immediately started, and this is used as the starting point for printing the first portion of the printing data.

[0091] S432: taking the position of the printing head 7 in the circumferential direction of the printing roller 5 when the edge of the printing medium 13 is detected as the starting point of printing the corresponding sub-printing data;

[0092] When the edge of the paper is detected, the starting point is determined and printing begins. After one printing pass is completed, that is, after the roller rotates one circle, the edge of the paper will trigger the paper edge sensor again. The system considers that the second printing pass has begun and takes this as the starting point of the second printing pass, and it will cycle in sequence until the set number of printing passes is completed. When the "paper jam" signal is detected, inkjet cannot be executed even if the paper edge signal is detected to avoid false triggering.

[0093] S434: The real-time position of the printing roller is obtained through an encoder tangent to the printing roller or a grating size installed on the surface of the roller, and the print head is controlled to print the print data corresponding to the real-time position in the sub-print data.

[0094] Since the print data corresponds to the pixels of the printed image, the print data includes the ink dot position of the corresponding pixel. Therefore, when the position of the print head 7 relative to the printing roller 5 in the circumferential direction reaches the position of the ink dot forming the pixel, the print data corresponding to the position is printed. In this way, the landing position of the ink dot corresponding to each pixel of the printed image can be accurately controlled during the rotation of the roller, thereby further improving the printing accuracy. Since the encoder is tangent to the printing roller, the arc length of the encoder is the same as the arc length of the printing roller. The real-time position of the printing roller can be calculated based on the arc length of the encoder and the diameter of the printing roller. Specifically, the following steps are also included:

[0095] S4331: Obtaining a rotation angle of a rotary encoder that rotates synchronously with the encoding wheel from the starting position, wherein the outer circumference of the encoding wheel is tangent to the outer circumference of the printing roller;

[0096] In the specific implementation, the rotary encoder and the code wheel are coaxially arranged so that the rotary encoder and the code wheel rotate synchronously. Since the outer circumference of the code wheel is tangent to the outer circumference of the printing roller, the arc length of the outer circumference of the printing roller is equal to the arc length of the outer circumference of the code wheel.

[0097] S4332: Obtain the diameter of the encoder wheel;

[0098] S4333: Determine the arc length of the outer surface of the encoder wheel according to the rotation angle of the rotary encoder and the diameter of the encoder wheel;

[0099] Assume that the angle of rotation of the rotary encoder is α, and the diameter of the encoder wheel is R. Since the encoder wheel and the rotary encoder rotate at the same angle, the arc length of the outer surface of the encoder wheel is 2πR (α / 360).

[0100] S4334: Determine the position of the print head in the circumferential direction of the printing roller according to the diameter of the outer circumferential surface of the printing roller and the arc length of the rotation of the outer circumferential surface of the encoding wheel.

[0101] Since the arc length of the rotation of the outer circular surface of the printing roller is equal to the arc length of the rotation of the outer circular surface of the encoding wheel, the rotation angle of the printing roller can be calculated based on the diameter of the outer circular surface of the printing roller and the arc length of the rotation of the outer circular surface of the encoding wheel. Combined with the starting point position, the position of the current print head in the circumferential direction of the printing roller can be obtained.

[0102] The diameter of the encoder wheel and the selection of the encoder accuracy can be determined according to the printing accuracy in the scanning direction of the print head. The calculation method is: R = 25.4 / P*C / 3.14

[0103] Among them, 25.4: is a constant; P is the printing accuracy, which is a preset value; C: is the encoder accuracy, which is a preset value; 3.14: is pi, which is a constant; R is the calculated diameter of the encoder wheel.

[0104] The technical method of printing accuracy is P = C*4 / (3.14*D)*25.4 / K

[0105] Among them, 4 is the encoder pulse number calculation constant. 3.14 is the pi, which is a constant. D is the printing roller monitoring wheel diameter, which is a preset value. 25.4 is a calculation constant. K is the frequency division and multiplication ratio, which is a preset value.

[0106] A more detailed flowchart can be found in Fig. 9 , wherein the data construction process is the aforementioned process of dividing the sub-print data according to the number of moves and the moving distance. Fig. 9 The X-axis refers to the circumferential direction of the printing roller, and the Y-axis refers to the axial direction of the printing roller.

[0107] In order to improve the printing effect, the present embodiment further performs a drying process on the printing medium 13 after printing. As an optional but advantageous implementation method, in the present embodiment, the steps of controlling the printing roller 5 to rotate unidirectionally and controlling the printing head 7 to print the sub-printing data one by one according to the position of the printing head 7 in the circumferential direction of the printing roller 5 during the unidirectional rotation of the printing roller 5, and moving the printing head 7 once along the axial direction of the printing roller 5 once each time a sub-printing data is printed until all the sub-printing data are printed after completion also include the following steps:

[0108] S5: When the print medium 13 is transported to the drying station, it enters the drying and curing stage. Figure 5 As shown, the drying stage includes the following steps: after receiving the paper sent out by the printing roller 5, the drying is automatically started.

[0109] S51: Obtaining a preset drying time;

[0110] The drying time of the drying unit is within a fixed drying length, and the time the paper stays in the drying area is also relatively fixed. This is conducive to the close cooperation of the front and back links, thereby improving production efficiency.

[0111] S52: Obtaining the printing ink volume of the image printed on the printing medium 13;

[0112] S53: determining a drying temperature for drying the print medium 13 according to the amount of printing ink of the image and a preset drying time; S54: controlling a drying device to dry the print medium 13 at the drying temperature.

[0113] S55: Obtaining a preset curing time;

[0114] S56: Determine a curing power for curing the print medium according to the amount of printing ink of the image and a preset curing time;

[0115] S57: Control the curing device to perform a curing process on the printing medium with the curing power.

[0116] In case that the amount of printed ink is large and the drying cannot be completed within the preset drying time, this embodiment further includes the following steps:

[0117] S531: If the determined drying temperature exceeds the allowable drying temperature, adjusting the drying temperature to the allowable drying temperature;

[0118] Since the drying temperature of the drying equipment cannot exceed its maximum allowable value, i.e. the allowable drying temperature, this step will reduce the drying temperature determined according to the preset drying time, but the drying cannot be completed within the preset drying time according to the adjusted drying temperature.

[0119] S532: Determine the actual drying time according to the allowable drying temperature and the amount of printing ink;

[0120] Since the allowable drying temperature is lower than the drying temperature set according to the preset drying time, the actual drying time consumed is less than the preset drying time;

[0121] S533: Determine the compensation drying time according to the actual drying time and the preset drying time;

[0122] The compensation drying time refers to the time required for drying at other stations to achieve the expected drying effect after drying at the drying station for the preset drying time;

[0123] S534: After the printing medium is dried at the drying station for a preset drying time, the printing medium is conveyed to the discharge bridge;

[0124] S535: Drying the printing medium while the printing medium passes through the discharge bridge, and the drying time is the supplementary drying time.

[0125] In this embodiment, the printing medium is transported to the next process after the time the printing medium has been in the drying station reaches the preset drying time, so that the next printing medium can enter the roller for printing, and the printing medium is additionally dried during the process of transporting the printing medium across the discharge bridge. This will not affect the overall printing efficiency and can ensure that the printing medium can be fully dried.

[0126] In this embodiment, the software can be used to automatically set the drying temperature and curing power according to the amount of ink in the image. By adjusting the drying temperature and curing power, it is ensured that the printed image on the paper is dried and cured within a fixed time.

[0127] As an optional but advantageous implementation, in this embodiment, after S53: determining the drying temperature for drying the print medium 13 according to the amount of printed ink of the image and the preset drying time, the following steps are also included:

[0128] S541: Acquire print data of a print image;

[0129] S542: determining the ink dot focus degree of the printed image according to the printing data of the printed image;

[0130] In this context, the focus degree of ink dots refers to the ratio of the area where the ink dots are located within a unit area on the print medium 13. The focus degrees of ink dots at different positions of the printed image may be different.

[0131] The printing data includes the position information of the ink dots in the image and the size information of the ink dots. The concentration degree of the ink dots can be obtained based on the above information, including:

[0132] The printed image is divided into a number of rectangular areas of the same shape, and the area occupied by the ink dots in each rectangular area is obtained according to the printing data. In specific implementation, the size of the ink dots can be first obtained according to the printing data, and then the area occupied by the ink dots on the printing medium 13 can be obtained according to the size of the ink dots. The sum of the areas occupied by all the ink dots in the rectangular area is the area occupied by the ink dots in the rectangular area. Finally, the area occupied by the ink dots in the rectangular area is divided by the area of ​​the rectangular area to obtain the focus degree of the ink dots.

[0133] S543: Adjust the drying temperature according to the ink dot focus degree.

[0134] Under the condition of the same printing ink volume, the degree of ink dot focus will also affect the drying time. Therefore, for the printed image with uneven ink dot distribution, there is still a certain error in the control of the drying time by selecting the drying temperature according to the printing ink volume. In this regard, the present embodiment further adjusts the drying temperature according to the concentration degree of ink dots while selecting the drying temperature according to the printing ink volume, so that the drying time can be more accurately controlled. Specifically, the following steps are included:

[0135] S5431: Obtaining the ink dot aggregation level interval;

[0136] The concentration of ink dots can be divided into a plurality of intervals, namely, ink dot concentration level intervals, according to the concentration of ink dots in advance;

[0137] S5432: Obtaining the drying temperature adjustment coefficient corresponding to each ink dot aggregation level interval;

[0138] Print images belonging to different ink dot aggregation level intervals but with the same amount of printing ink can be printed on different printing media 13 in advance. Then, experiments are conducted to obtain the drying temperatures required for each ink dot aggregation level interval to complete drying within the same time. Then, the drying temperature required for one of the ink dot aggregation level intervals is selected as the reference temperature. Generally, the drying temperature required for the interval with the lowest ink dot aggregation degree is selected as the reference temperature. The drying temperatures required for other ink dot aggregation level intervals divided by the reference temperature are used as the temperature adjustment coefficient.

[0139] S5433: adjusting the drying temperature according to the drying temperature adjustment coefficient;

[0140] In this step, the original drying temperature is multiplied by the temperature adjustment coefficient to obtain a new drying temperature.

[0141] like Figure 6 As shown, as an optional but advantageous implementation, in this embodiment, the method further includes the following steps:

[0142] S01: Detect whether the printing carriage is in the printing area;

[0143] S02: When it is detected that the printing carriage is in the printing area, the surface height of the printing medium 13 is detected;

[0144] After the paper enters the roller, it may warp due to various factors, which means that the height of the printing medium 13 may exceed the normal value. Since the distance between the nozzle and the outer surface of the roller is very small, the warping and arching of the paper are very easy to scratch the nozzle of the nozzle, which may seriously damage the nozzle. Therefore, on the outer side of the roller, when the paper enters the printing area, the paper warping sensor is used to detect the surface height of the printing medium 13.

[0145] S03: When it is detected that the surface height of the printing medium 13 exceeds a preset height, a printing medium 13 abnormal trigger signal is generated;

[0146] The preset height is a height that can ensure that the printing medium 13 does not contact the nozzle. When it is detected that the surface height of the printing medium 13 exceeds the preset height, a trigger signal indicating that the printing medium 13 is abnormal is immediately generated.

[0147] S04: When an abnormal trigger signal of the printing medium 13 is detected, the inkjet signal is stopped from being output to the print head 7, and the print head is controlled to move away from the printing roller 5. In order to quickly move the print head away from the printing roller, the print head moves in the radial direction of the printing roller.

[0148] When the paper is detected to be arched, the inkjet signal output of the print head 7 is stopped, and the print head is automatically lifted immediately to allow the warped part to safely pass through the print head printing area. The system automatically determines it as defective paper and automatically moves the paper out of the roller when it reaches the paper output position.

[0149] like Figure 7 As shown, as an optional but advantageous implementation, in this embodiment, when an abnormal trigger signal of the printing medium 13 is detected, the following steps are also included:

[0150] S61: Determine whether there is a printing medium 13 in the current drying station;

[0151] If the last sheet is printed normally, the printing time is relatively fixed, and the drying time is relatively fixed. At this time, the print medium 13 of the output roller will touch the previous print medium 13, affecting the drying. In this regard, the present embodiment first determines whether there is a print medium 13 at the drying position before the paper is output.

[0152] S62: If yes, the printing roller 5 is controlled to drive the printing medium 13 to continue to rotate along with the printing roller 5;

[0153] If there is paper that needs to be removed, the roller will continue to rotate until the paper is discharged from the drying position.

[0154] Alternatively, another paper outlet can be set up below the drying position for waste discharge, and the waste paper determined by the system to be defective can be sent here to speed up the printing turnover rate. At the same time, the system should record the amount of waste paper, continue to give paper feeding signals, and make up the number of prints.

[0155] S63: If not, the printing medium 13 on the printing roller 5 is transported to the drying station.

[0156] If there is no printing medium 13, the printing medium 13 that has been printed currently can be sent to a drying station for drying.

[0157] As an optional but advantageous implementation, in this embodiment, a plurality of air suction holes are provided on the outer circumferential surface of the printing roller 5. In the S4: the printing roller 5 is controlled to rotate unidirectionally, and the printing head 7 is controlled to print the sub-print data one by one according to the position of the printing head 7 in the circumferential direction of the printing roller 5 during the unidirectional rotation of the printing roller 5. Each time a sub-print data is printed, the printing head 7 moves once along the axial direction of the printing roller 5 until all the sub-print data are printed and the printing medium 13 enters the roller-out stage, as shown in FIG. Figure 8 As shown, the printing medium 13 roll-out stage includes the following steps:

[0158] S71: dividing the outer circumferential surface of the printing roller 5 into a plurality of adsorption areas along the circumferential direction, and determining the air suction holes contained in each adsorption area;

[0159] In this embodiment, the printing medium 13 can be adsorbed to the outer circumferential surface of the printing roller 5 by using the suction holes provided on the printing roller 5 , so that the printing medium 13 can rotate together with the printing roller 5 .

[0160] For example, the outer circumferential surface of the printing roller 5 can be divided into k adsorption areas along the circumferential direction, and the air suction holes in each adsorption area can be controlled independently.

[0161] S72: Acquire the current rotational angular position of the printing roller 5;

[0162] S73: determining the distance between each adsorption area on the outer circumferential surface of the printing roller 5 and the next link according to the current rotational angular position of the printing roller 5;

[0163] The distances between each adsorption area on the outer surface of the printing roller 5 and the next link are different, and the part of the printing medium 13 closer to the adsorption area of ​​the next link will enter the next link first.

[0164] S74: Control the suction force and / or switch of the suction holes of each adsorption area according to the distance between each adsorption area and the next link.

[0165] For example, the suction holes of the adsorption area closest to the next link can be closed first. Since the printing roller 5 is rotating, the adsorption area closest to the next link is also constantly changing. As the printing roller rotates, the part of the printed record close to the next link is gradually separated from the printing roller 5, so that the printing medium 13 can be quickly and smoothly separated from the printing roller and enter the next link.

[0166] As an optional but advantageous implementation, in this embodiment, the nozzles of the print head 7 are all oriented toward the center of the roller, and the plane where the nozzles in the same row of the print head 7 are located is parallel to the axis of the printing roller 5. With the above structure, the portion of the print medium 13 passing under the nozzles can always remain parallel to the nozzle plane of the first nozzle and maintain the same distance during the rotation of the printing medium 13 with the printing roller 5, which can significantly improve the printing accuracy and printing stability.

[0167] Example 2

[0168] like Fig. 9 As shown, this embodiment provides a drum-type scanning printing device, which includes a printing roller 5, a first driving mechanism, a print head 7 and a control circuit, wherein the first driving mechanism is used to drive the printing roller 5 to rotate, and the control circuit is electrically connected to the print head 7 and the first driving mechanism, and the control circuit includes at least one processor, at least one memory and computer program instructions stored in the memory, and when the computer program instructions are executed by the processor, the method described in Example 1 is implemented. The first driving mechanism can adopt a servo motor 6. The printing device also includes a rotary encoder 8 for detecting the rotational position of the printing roller 5. The printing device also includes a printing drying box 9, which is arranged at the bottom of the printing roller 5. As shown Fig.10 As shown, a discharge bridge 10 is provided on the outlet side of the printing and drying box 9 , a discharge buffer 11 is provided on the outlet side of the discharge bridge 10 , and a material receiver 12 is provided on the outlet side of the discharge buffer 11 .

[0169] The outer circumferential surface of the printing roller 5 is provided with suction holes. When the suction holes are connected to the negative pressure chamber, the suction holes can absorb the printing medium 13 covering the outer circumferential surface of the lower printing roller onto the printing roller 5. The suction area will adapt to the size of the paper according to the size of the paper. The closed cavity in each sub-area can reduce the pressure loss. When the paper is fed into the roller and delivered out of the roller, the work of the suction holes is just the opposite. When the roller is feeding the paper into the roller, it is necessary to absorb the paper in sections in the order when the paper is pressed into the roller surface to reduce the arching of the paper; when the roller is delivering the paper out of the roller, after the bite sends the paper out, part of the paper remains on the roller surface. In order to ensure that the paper is delivered more smoothly, the suction needs to be closed in sections.

[0170] like Fig.10 As shown, the device also includes a feeder 1, the printing medium 13 is stacked in the storage cavity of the feeder 1, and a feeder device 2 is arranged on the top of the feeder 1. A feed buffer 3 is arranged on the outlet side of the feeder device 2. A feed bridge 4 is arranged between the printing roller 5 and the outlet of the feed buffer 3.

[0171] Specifically, the processor may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present invention.

[0172] The memory may include a large capacity memory for data or instructions. By way of example and not limitation, the memory may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. Where appropriate, the memory may include a removable or non-removable (or fixed) medium. Where appropriate, the memory may be inside or outside a data processing device. In a particular embodiment, the memory is a non-volatile solid-state memory. In a particular embodiment, the memory includes a read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM) or a flash memory or a combination of two or more of these.

[0173] The processor implements the printing method in the above embodiment by reading and executing the computer program instructions stored in the memory.

[0174] In one example, the display screen of this embodiment may also include a communication interface and a bus, wherein the processor, the memory, and the communication interface are connected through the bus and communicate with each other.

[0175] The communication interface is mainly used to realize the communication between each module, device, unit and / or equipment in the embodiment of the present invention. The bus includes hardware, software or both, and couples the various components used for the display screen to each other. For example and not limitation, the bus may include an accelerated graphics port (AGP) or other graphics bus, an enhanced industrial standard architecture (EISA) bus, a front-end bus (FSB), a hypertransport (HT) interconnect, an industrial standard architecture (ISA) bus, an infinite bandwidth interconnect, a low pin count (LPC) bus, a memory bus, a microchannel architecture (MCA) bus, a peripheral component interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a serial advanced technology attachment (SATA) bus, a video electronics standard association local (VLB) bus or other suitable buses or a combination of two or more of these. Where appropriate, the bus 410 may include one or more buses. Although the embodiments of the present invention describe and illustrate specific buses, the present invention considers any suitable bus or interconnect.

[0176] The above is a detailed introduction to the roller-type unidirectional rotation scanning and printing method, device and roller-type scanning and printing equipment provided by the embodiments of the present invention.

[0177] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0178] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0179] It should also be noted that the exemplary embodiments mentioned in the present invention describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiments, or in a different order from the embodiments, or several steps can be performed simultaneously.

[0180] The above is only a specific implementation of the present invention. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be covered within the protection scope of the present invention.

Claims

1. A drum-type unidirectional rotating scanning printing method, characterized in that: The printing medium for printing is coated on the outer circumferential surface of the printing roller, and the method comprises the following steps: Obtaining the number of times the print head moves along the axial direction of the printing roller after printing starts, the distance of each movement, and the target number of rotations of the printing roller determined by the printing requirements; Acquire printing data of the image to be printed; Dividing the print data into a number of sub-print data according to the number of times the print head moves along the axial direction of the printing roller and the distance of each movement, wherein the number of sub-print data is the same as the number of times the print head moves along the axial direction of the printing roller; Controlling the printing roller to rotate unidirectionally, and controlling the printing head to print the sub-printing data one by one according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller, and each time the printing of a sub-printing data is completed, the printing head moves once along the axial direction of the printing roller until all the sub-printing data are printed; The method of controlling the printing roller to rotate unidirectionally, and controlling the printing head to print the sub-printing data one by one according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller, and moving the printing head once along the axial direction of the printing roller each time the printing of a sub-printing data is completed until all the sub-printing data are printed, comprises the following steps: S41: Obtaining the number of times the current print head moves along the axial direction of the printing roller; S42: acquiring sub-printing data corresponding to the number of movement times according to the number of movement times; S43: controlling the printing roller to rotate unidirectionally for one circle, and controlling the printing head to print the corresponding sub-printing data according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation; S44: After the corresponding sub-printing data is printed, the printing medium is solidified, and the printing head is controlled to move once in the axial direction of the printing roller before the next sub-printing data starts printing; S45: repeating the above steps S41 to S44 until all sub-printing data are printed; The step S43: controlling the printing roller to rotate one circle in one direction, and controlling the printing head to print the corresponding sub-printing data according to the position of the printing head in the circumferential direction of the printing roller during the one circle rotation includes the following steps: Perform edge detection of printing media during unidirectional rotation of the printing roller; The position of the printing head in the circumferential direction of the printing roller when the edge of the printing medium is detected is used as the starting point of printing the corresponding sub-printing data; The real-time position of the printing roller is obtained by the size of the grating installed on the surface of the roller, and the print head is controlled to print the print data corresponding to the real-time position in the sub-print data; The method of controlling the printing roller to rotate unidirectionally and controlling the printing head to print the sub-printing data one by one according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller, wherein each time a sub-printing data is printed, the printing head moves once along the axial direction of the printing roller until all the sub-printing data are printed, further comprises the following steps: When the printing medium is transported to the drying station, it enters the drying and curing stage, which includes the following steps: Get the preset drying time; Obtaining the amount of printing ink of an image printed on a printing medium; Determining a drying temperature for drying the print medium according to the amount of print ink of the image and a preset drying time; Controlling the drying device to dry the printing medium at the drying temperature; Get the preset curing time; Determining a curing power for curing the print medium according to the amount of printed ink of the image and a preset curing time; Controlling the curing device to perform curing processing on the printing medium with the curing power; After determining the drying temperature for drying the print medium according to the amount of printed ink of the image and the preset drying time, the method further includes the following steps: Obtaining print data for printing an image; Determining the ink dot focusing degree of the printed image according to the printing data of the printed image; Adjust the drying temperature according to the degree of ink dot focus. Obtaining the ink dot aggregation level range; Obtain the drying temperature adjustment coefficient corresponding to each ink dot aggregation level interval; The drying temperature is adjusted according to the drying temperature adjustment coefficient.

2. The drum-type unidirectional rotating scanning printing method according to claim 1, characterized in that: The method further comprises the following steps: Detect whether the printing carriage is in the printing area; When it is detected that the printing carriage is in the printing area, the surface height of the printing medium is detected; When the height of the printing medium surface is detected to exceed a preset height, a printing medium abnormality trigger signal is generated; When an abnormal trigger signal of the printing medium is detected, the inkjet signal output to the printing nozzle is stopped, and the nozzle is controlled to move in a direction away from the printing roller.

3. The drum-type unidirectional rotation scanning printing method according to claim 2, characterized in that: When the abnormal trigger signal of the printing medium is detected, the following steps are also included: Determine whether there is printing medium in the current drying station; If yes, the printing roller is controlled to drive the printing medium to continue rotating with the printing roller; Otherwise, the printed media on the printing roller is transported to the drying station.

4. The drum-type unidirectional rotation scanning printing method according to any one of claims 1 to 3, characterized in that: A plurality of air suction holes are arranged on the outer circumferential surface of the printing roller, and the printing roller is controlled to rotate unidirectionally, and the printing head is controlled to print the sub-printing data one by one according to the position of the printing head in the circumferential direction of the printing roller during the unidirectional rotation of the printing roller. Each time a sub-printing data is printed, the printing head moves once along the axial direction of the printing roller until all the sub-printing data are printed and then enters the printing medium roller discharge stage, and the printing medium roller discharge stage includes the following steps: The outer circumferential surface of the printing roller is divided into a plurality of adsorption areas along the circumferential direction, and the air suction holes contained in each adsorption area are determined; Get the current angular position of the printing roller; Determine the distance between each adsorption area on the outer cylindrical surface of the printing roller and the next link according to the current rotational angular position of the printing roller; The suction force and / or switching of the suction holes of each adsorption area are controlled according to the distance between each adsorption area and the next link.

5. The drum-type unidirectional rotation scanning printing method according to any one of claims 1 to 3, characterized in that: The nozzles of the printing head are all oriented toward the center of the roller, and the plane where the nozzles in the same row of the printing head are located is parallel to the axis of the printing roller.

6. A drum type scanning and printing device, characterized in that: The method comprises a printing roller, a first driving mechanism, a print head and a control circuit, wherein the first driving mechanism is used to drive the printing roller to rotate, the control circuit is electrically connected to the print head and the first driving mechanism, and the control circuit comprises at least one processor, at least one memory and computer program instructions stored in the memory, and when the computer program instructions are executed by the processor, the method as described in any one of claims 1 to 5 is implemented.

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