Single-nozzle drum-type high-speed digital inkjet printer and printing control method

Abstract

The present invention discloses a single-nozzle drum-type high-speed digital inkjet printer and a printing control method. The high-speed digital inkjet printer includes a paper feeding mechanism and a paper receiving mechanism. A printing drum is arranged between the paper feeding mechanism and the paper receiving mechanism, and a nozzle assembly is arranged above the printing drum. The printing drum is a no-gripping-tooth type suction drum, and the printing drum is cooperatively provided with a paper turning mechanism and a paper separating mechanism for separating the paper adsorbed on the surface of the drum. The paper separating mechanism is connected with the paper receiving mechanism. The paper turning mechanism includes a paper lifting suction wheel, a paper returning suction wheel, a paper temporary storage assembly and a detection sensor. This inkjet printer only needs a no-gripping-tooth type suction drum as the printing drum, and the overall structure design is simple. Without a gripper bar row, accurate paper transfer can be achieved. The paper turning mechanism has a simple design, a short transfer path, good turning smoothness, and is beneficial to improving the printing efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of inkjet printing machinery, and in particular relates to a single-nozzle drum-type high-speed digital inkjet printer and a printing control method. Background Art

[0002] Sheet-fed digital inkjet printing machinery can realize single-sided printing or double-sided printing of single-sheet paper according to customer printing requirements. The sheet-fed inkjet printing process requires high paper positioning accuracy.

[0003] In the prior art, most single-sheet digital inkjet printers use rollers to carry and transfer paper. The paper is transferred between units by the printing roller, the paper transfer roller or the gripper row on the conveyor chain. The printing roller is used to carry the paper to complete the printing operation. An inkjet head is arranged above the printing roller. When the paper rotates with the printing roller to the bottom of the inkjet head, the inkjet head prints the paper. Although the roller with the gripper row has high positioning accuracy for the paper, its manufacturing cost is also high, and the failure rate of the gripper row is also high.

[0004] After the front side of the paper is printed, the paper needs to be turned over by a flipping mechanism to convert the head of the paper into the tail of the paper before being fed into the printing roller for reverse printing. Currently, there are two main flipping mechanisms for digital inkjet printers: one is to use a paper swinging mechanism with a paper gripper row in conjunction with a roller or chain transmission mechanism to achieve the conversion between the head and the tail of the paper. This flipping method has a more complex structural design, and the paper is prone to wrinkles when swinging the paper. The paper is not turned over smoothly, and the failure rate is higher. The other is an adsorption-type turning mechanism, which includes a suction belt, which is wound around two suction wheels that can rotate forward and backward. When the suction wheel drives the suction belt to rotate forward, the suction belt adsorbs the head side of the paper on the roller to temporarily store the paper. When the suction wheel drives the suction belt to reverse, the temporarily stored paper is re-transferred from the tail side of the paper to the paper feed belt to realize paper turning. The paper feed belt then feeds the turned paper back to the printing roller for reverse printing. Although this turning method simplifies the structure and has good smoothness in paper turning, after the suction belt rotates forward to temporarily store the paper, when it reverses to transmit the paper, it needs to pass through the paper feed belt to transmit the paper back to the printing roller. The paper transmission path is long, which affects the printing efficiency. Summary of the invention

[0005] In view of the above shortcomings in the prior art, the technical problem to be solved by the present invention is to provide a single-nozzle drum high-speed digital inkjet printer with a simple structural design, which can achieve accurate paper transfer without a paper gripper row, has a short paper transfer path, good turning smoothness, and is conducive to improving printing efficiency.

[0006] To solve the above technical problems, the technical solution of the present invention is: a single-nozzle drum-type high-speed digital inkjet printer, including a paper feeding mechanism and a paper receiving mechanism. A printing drum is arranged between the paper feeding mechanism and the paper receiving mechanism, and a nozzle assembly is arranged above the printing drum; the printing drum is a toothless suction drum, the printing drum has a paper release area and a paper adsorption area, the paper adsorption area is a constant negative pressure area, and the paper release area is a non-negative pressure area; the printing drum is cooperatively provided with a paper turning mechanism and a paper separation mechanism for separating the paper adsorbed on the drum surface, and the paper separation mechanism is connected with the paper receiving mechanism;

[0007] The paper turning mechanism includes a paper lifting suction wheel, a paper returning suction wheel, a paper temporary storage assembly and a detection sensor; the paper lifting suction wheel is rotatably arranged outside the paper release area of the printing drum, the paper lifting suction wheel is provided with a paper lifting adsorption area, and the paper lifting adsorption area is an instantaneous negative pressure area; the paper returning suction wheel is rotatably arranged outside the paper adsorption area of the printing drum, the paper returning suction wheel is provided with a paper feeding adsorption area, and the paper feeding adsorption area is also an instantaneous negative pressure area; the paper temporary storage assembly is arranged between the paper lifting suction wheel and the paper returning suction wheel; the detection sensor is arranged at the tail of the paper temporary storage assembly.

[0008] As a preferred technical solution, the printing drum includes a drum body, and two or more rows of air holes are formed on the surface of the drum body. Air ducts are respectively arranged in the drum body corresponding to each air exhaust hole, and the air ducts are communicated with the corresponding air holes; a first conduction member is cooperatively arranged at the end of the drum body, the drum body and the first conduction member can rotate relatively, and a paper feeding side strong adsorption area, a paper feeding side holding adsorption area, a paper turning side strong adsorption area and a paper turning side holding adsorption area are sequentially formed in the first conduction member along the rotation direction of the drum body; when the drum body rotates, each air duct is respectively communicated with the corresponding area when passing through each area in sequence.

[0009] As a preferred technical solution, the negative pressure of the paper feeding side strong adsorption area and the paper turning side strong adsorption area is greater than the negative pressure of the paper feeding side holding adsorption area and the paper turning side holding adsorption area.

[0010] As a preferred technical solution, the covering areas of the paper feeding side strong adsorption area and the paper turning side strong adsorption area can respectively only cover one air duct.

[0011] As a preferred technical solution, the covering areas of the paper feeding side holding adsorption area and the paper turning side holding adsorption area can respectively cover at least two air ducts.

[0012] As a preferred technical solution, the paper separation mechanism is a positive pressure blowing area arranged in the first conduction member and located downstream of the paper feeding side holding adsorption area. When the paper head of the paper passes through the positive pressure blowing area, it is instantly blown off the drum surface.

[0013] As a preferred technical solution, the paper separation mechanism is a swingable separation plate, and when the separation plate swings to the surface of the drum, it is tangent to the drum body.

[0014] As a preferred technical solution, the paper separation mechanism is a swingable separation hook, and an annular groove matched with the separation hook is formed on the circumferential surface of the drum body.

[0015] As a preferred technical solution, the paper lifting and air suction wheel includes a wheel body, and more than two rows of air holes are formed on the surface of the wheel body. Air ducts are respectively arranged in the wheel body corresponding to each air exhaust hole, and the air ducts are communicated with the corresponding air holes; a second conduction member is arranged at the end of the wheel body in a matching manner, the wheel body and the second conduction member can rotate relatively, the second conduction member is connected to a negative pressure device through a pipeline, and an electromagnetic control valve is installed on the pipeline.

[0016] The present invention also provides a printing control method for the single-nozzle drum-type high-speed digital inkjet printer described above:

[0017] During single-sided printing, the paper feeding mechanism conveys the paper to the printing drum. When the paper head of the paper passes through the strong adsorption area on the paper feeding side, it is instantaneously adsorbed to the surface of the drum and accurately positioned; when the paper is adsorbed on the printing drum and rotates with the drum to the lower part of the nozzle assembly, the nozzle assembly performs single-sided printing on the paper. When the paper after single-sided printing rotates with the drum to the paper separation mechanism, the paper separation mechanism acts to separate the paper adsorbed on the surface of the drum and then convey it to the paper receiving mechanism;

[0018] During double-sided printing, the paper separation mechanism acts alternately; when performing front-side printing, the paper feeding mechanism conveys the paper to the printing drum. When the paper head of the paper passes through the strong adsorption area on the paper feeding side, it is instantaneously adsorbed to the surface of the drum and accurately positioned; when the paper is adsorbed on the printing drum and rotates with the drum to the lower part of the nozzle assembly, the nozzle assembly performs front-side printing on the paper. When the paper after front-side printing rotates with the drum to the paper separation mechanism, the paper separation mechanism does not act. When the paper continues to rotate with the drum to the paper release area, the paper lifting adsorption area of the paper lifting and air suction wheel instantaneously accesses negative pressure, and the paper lifting and air suction wheel instantaneously adsorbs the paper and lifts the paper to the paper temporary storage assembly for temporary storage; when the detection sensor detects that the paper head reaches the set position, the paper lifting adsorption area of the paper lifting and air suction wheel instantaneously disconnects the negative pressure, and at the same time, the paper feeding adsorption area of the paper returning and air suction wheel instantaneously accesses negative pressure, and the paper returning and air suction wheel instantaneously adsorbs the paper tail and conveys the paper to the paper adsorption area of the printing drum, and the paper is re-adsorbed to the surface of the printing drum. Since then, the paper tail is converted into the paper head to complete the turning over. When the paper continues to be adsorbed on the printing drum and rotates with the drum to the lower part of the nozzle assembly again, the nozzle assembly performs back-side printing on the paper; when the paper after positive and negative double-sided printing rotates with the drum to the paper separation mechanism, the paper separation mechanism acts to separate the paper adsorbed on the surface of the drum and then convey it to the paper receiving mechanism.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] (1) Only one air suction drum without grippers is required as the printing drum in the whole device. The printing drum has a paper release area and a paper adsorption area. When the leading edge of a single sheet of paper reaches the paper adsorption area, the leading edge is instantaneously adsorbed by a relatively large negative pressure and is accurately positioned on the drum surface, playing the role of gripper handover. When the leading edge of the printed paper rotates with the drum to the paper separation mechanism, the paper gradually detaches from the drum surface under the action of the paper separation mechanism and is output. The overall structure design is simple, and accurate paper handover and transmission can be achieved without a paper gripper row.

[0021] (2) The turning mechanism includes a paper lifting air suction wheel, a paper returning air suction wheel, a paper temporary storage component, and a detection sensor. When the leading edge of the paper adsorbed on the surface of the printing drum rotates with the drum to the paper release area, the paper lifting adsorption area of the paper lifting air suction wheel instantaneously accesses negative pressure, and the paper lifting air suction wheel instantaneously adsorbs the paper and lifts it to the paper temporary storage component for temporary storage. When the leading edge of the paper reaches the set position, the paper lifting adsorption area of the paper lifting air suction wheel instantaneously disconnects the negative pressure, and at the same time, the paper feeding adsorption area of the paper returning air suction wheel instantaneously accesses negative pressure. The paper returning air suction wheel instantaneously adsorbs the trailing edge of the paper and conveys the paper to the paper adsorption area of the printing drum, and the paper is re-adsorbed on the surface of the printing drum. Since then, the trailing edge is converted into the leading edge to complete the turning. In this way, only by using the cooperation of two air suction wheels and the opening and closing of electromagnetic control valves, the conversion and turning of the paper from the trailing edge to the leading edge can be realized. The structure design is simple, the manufacturing cost is low, and during the turning process, the paper has a short transmission path from starting to detach from the printing drum to returning to the printing drum, and the turning smoothness is good, which is beneficial to improving the printing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0023] Figure 1 is a schematic structural diagram of a single-nozzle drum-type high-speed digital inkjet printer provided by an embodiment of the present invention;

[0024] Figure 2 is a schematic diagram of the cooperation between the printing drum and the turning mechanism in an embodiment of the present invention;

[0025] Figure 3 is a schematic side view structure diagram of the printing drum in an embodiment of the present invention;

[0026] Figure 4 is Figure 3 a schematic cross-sectional view taken along the line A-A in

[0027] Figure 5 is a schematic front view structure diagram of the paper lifting air suction wheel in an embodiment of the present invention;

[0028] Figure 6 It is a schematic side view structure diagram of the paper lifting suction wheel in the embodiment of the present invention;

[0029] Figure 7 It is a state reference diagram when the paper lifting suction wheel lifts the paper from the surface of the printing cylinder to the paper temporary storage assembly;

[0030] Figure 8 It is a state reference diagram when the paper returning suction wheel instantaneously adsorbs the tail of the paper and is ready to transfer the paper to the paper adsorption area of the printing cylinder;

[0031] Figure 9 It is a state reference diagram when the paper is re-adsorbed onto the surface of the printing cylinder and the tail of the paper is converted into the head of the paper to complete the turning over;

[0032] Figure 10 It is a state reference diagram when a single sheet of paper is adsorbed and transferred by the cylinder;

[0033] Figure 11 It is a state reference diagram when the separation plate is not working;

[0034] Figure 12 It is a state reference diagram when the separation plate is working;

[0035] Figure 13 It is a schematic structure diagram when an annular groove is provided on the printing cylinder;

[0036] Figure 14 is Figure 13 the schematic cross-sectional structure diagram in the C-C direction of;

[0037] Figure 15 It is a state reference diagram when the separation hook is not working;

[0038] Figure 16 It is a state reference diagram when the separation hook is working. Detailed implementation mode

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the following detailed description, only some exemplary embodiments of the present invention are described by way of illustration. Undoubtedly, those of ordinary skill in the art can recognize that the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the drawings and the description are illustrative in nature and are not used to limit the protection scope of the claims.

[0040] Such as Figure 1As shown, a single-nozzle drum-type high-speed digital inkjet printer includes a paper feeding mechanism 10 and a paper receiving mechanism 20. A printing drum 30 is arranged between the paper feeding mechanism 10 and the paper receiving mechanism 20. Above the printing drum 30, there is a nozzle assembly 40 for printing on the paper that rotates to this position with the drum. The paper feeding mechanism 10, the paper receiving mechanism 20, and the nozzle assembly 40 are common and well-known structures in the art, and will not be elaborated here. The printing drum 30 is provided with a turning mechanism 50 and a paper separation mechanism for separating the paper adsorbed on the drum surface, and the paper separation mechanism is connected to the paper receiving mechanism 20.

[0041] Reference Figure 2 , the printing drum 30 is a toothless suction drum, and the printing drum 30 has a paper release area 31 and a paper adsorption area 32. The paper adsorption area 32 is a constant negative pressure area, and the paper release area 31 is a non-negative pressure area (which can be normal pressure or positive pressure); specifically, reference Figures 2 to 4 , the printing drum 30 includes a drum body 33. On the surface of the drum body 33, there are two or more rows of air holes 34. The air holes 34 in the same row are evenly distributed along the axial direction of the drum body 33, and the air holes 34 in different rows are annularly distributed along the circumferential surface of the drum body 33; corresponding to each row of air holes 34 in the drum body 33, there are air ducts 35 respectively, and the air ducts 35 are communicated with the corresponding air holes 34, and each air duct 35 is located on the same circumferential surface;

[0042] At the end of the drum body 33, a first conducting member 36 is cooperatively arranged. The drum body 33 and the first conducting member 36 can rotate relative to each other, that is, the drum body 33 is rotatably arranged, and the first conducting member 36 is fixedly arranged; in the first conducting member 36, a strong adsorption area 321 on the paper feeding side, a holding adsorption area 322 on the paper feeding side, a strong adsorption area 323 on the turning side, and a holding adsorption area 324 on the turning side are sequentially formed along the rotation direction of the drum body 33; when the drum body 33 rotates, each air duct is communicated with the corresponding area when passing through each area in sequence; these areas together form the paper adsorption area. Of course, the setting positions of each area can be appropriately adjusted according to the paper specifications or the handover position requirements. In this embodiment, the strong adsorption area 321 on the paper feeding side and the strong adsorption area 323 on the turning side are respectively arranged corresponding to the paper input handover position on the paper feeding side and the paper turning handover position on the other side.

[0043] Of course, to avoid air leakage, the areas of the first conducting member 36 other than the paper adsorption area are rotatably and sealingly cooperated with the end face of the drum body 13.

[0044] Reference Figure 2 and Figure 3, a connector 37 corresponding to each strong adsorption area and holding adsorption area is arranged on the first conducting member 36. Through the connector 37, the strong adsorption area and the holding adsorption area can be respectively and independently and quickly connected to the negative pressure source. The negative pressure in the strong adsorption area is preferably greater than that in the holding adsorption area, that is, the negative pressure in the sheet feeding side strong adsorption area and the sheet turning side strong adsorption area is greater than that in the sheet feeding side holding adsorption area and the sheet turning side holding adsorption area. Among them, the negative pressure value in the strong adsorption area is preferably 60-100 Kpa. When working like this, after the strong adsorption area instantaneously adsorbs and positions the paper head of the paper, the paper is held and adsorbed on the surface of the drum through the holding adsorption area, which can save wind energy consumption on the basis of stable and reliable transmission.

[0045] Reference Figure 2 , the covering areas of the sheet feeding side strong adsorption area 321 and the sheet turning side strong adsorption area 323 can respectively only cover one air duct. The covering areas of the sheet feeding side holding adsorption area 322 and the sheet turning side holding adsorption area 324 can respectively cover multiple air ducts. The covering area of the strong adsorption area is small, which is convenient for forming an instantaneous strong adsorption force on the paper on the surface of the drum, playing the role of the gripper "bite". The paper head is subjected to a large negative pressure adsorption effect and will be instantaneously adsorbed to the surface of the drum and accurately positioned.

[0046] Reference Figure 2 , the sheet turning mechanism 50 includes a paper lifting suction wheel 51, a paper returning suction wheel 52, a paper temporary storage component 53 and a detection sensor 54; the paper lifting suction wheel 51 is rotatably arranged outside the paper release area 31 of the printing drum 30, and the paper lifting suction wheel 51 is provided with a paper lifting adsorption area 511, and the paper lifting adsorption area 511 is an instantaneous negative pressure area; specifically, reference Figure 5 and Figure 6 , the paper lifting suction wheel 51 includes a wheel body 512, two or more rows of air holes are formed on the surface of the wheel body 512, air ducts are respectively arranged in the wheel body 512 corresponding to the air exhaust holes, and the air ducts are communicated with the corresponding air holes; a second conducting member 513 is cooperatively arranged at the end of the wheel body 512, the wheel body 512 and the second conducting member 513 can rotate relative to each other, that is, the wheel body 512 is rotatably arranged and the second conducting member 513 is fixedly arranged; the second conducting member 513 is connected to the negative pressure device through a pipeline. When the wheel body 512 rotates, each air duct is communicated with the second conducting member 513 when passing through the second conducting member 513, thereby forming the paper lifting adsorption area 511. An electromagnetic control valve is installed on the pipeline connecting the second conducting member 513 to the negative pressure device, and the on-off state of the negative pressure in the paper lifting adsorption area 511 can be controlled by the high-frequency opening and closing of the electromagnetic control valve.

[0047] Reference Figure 2, the paper return suction wheel 52 is rotatably arranged outside the strong adsorption area 323 on the reverse side of the printing cylinder 30. The paper return suction wheel 52 is provided with a paper feeding adsorption area 521, and the paper feeding adsorption area 521 is also an instantaneous negative pressure area; the structural principle of the paper return suction wheel 52 is the same as that of the paper lifting suction wheel 51, and will not be elaborated here.

[0048] The paper temporary storage assembly 53 is arranged between the paper lifting suction wheel 51 and the paper return suction wheel 52 for temporarily storing the paper, and it can adopt an output paper belt, etc. The detection sensor 54 is arranged at the tail of the paper temporary storage assembly 53 for detecting and sensing the position of the paper head of the paper.

[0049] The paper separation mechanism can be realized in various ways to separate the paper adsorbed on the surface of the cylinder, and all of them should fall within the protection scope of the present invention.

[0050] Reference Figure 10 , the paper separation mechanism can be a positive pressure blowing area 61 arranged in the first conduction member and downstream of the paper feeding side holding adsorption area. When the paper head of the paper passes through the positive pressure blowing area 61, it is instantly blown off the surface of the cylinder. As the cylinder rotates, the paper gradually detaches from the cylinder under the guiding action of the arc-shaped guide plate 62 and is output and transmitted to the paper receiving mechanism by the output paper belt.

[0051] Reference Figure 11 , Figure 12 , the paper separation mechanism can be a swinging separation plate 63, and the separation plate 63 is connected to the output paper belt. At this time, there is no need to set a positive pressure blowing area. Reference Figure 11 , when the paper is normally adsorbed on the cylinder body 33 and rotates with the cylinder, the separation plate 63 does not contact the surface of the cylinder body 33; Reference Figure 12 , when it is necessary to transfer and output the paper, the separation plate 63 swings to be tangent to the surface of the cylinder body 33. After the paper head of the paper contacts the separation plate 63, under the forcing action of the separation plate 63, the paper gradually detaches from the cylinder and is output and transmitted to the paper receiving mechanism by the output paper belt.

[0052] Reference Figures 13 to 16 , the paper separation mechanism is a swingable separation hook 64. An annular groove 65 matching with the separation hook 64 is formed along the circumferential surface of the cylinder body 33, and the groove depth is about 1 mm. The hook tail of the separation hook 64 is connected to the output paper belt. Reference Figure 15 , when the paper normally rotates with the cylinder body 33, the hook tip of the separation hook 64 does not extend into the annular groove 65; Reference Figure 16 , when it is necessary to transfer and output the paper, the separation hook 64 rotates and swings, and the hook tip part extends into the annular groove 65. After the paper head of the paper contacts the hook tip of the separation hook 64, under the forcing action of the separation hook 64, the paper gradually detaches from the cylinder and is output and transmitted to the paper receiving mechanism by the output paper belt.

[0053] ReferenceFigures 1 to 10 , the printing control method of this inkjet printer is as follows:

[0054] During single-sided printing, the paper feeding mechanism 10 transports the paper to the printing drum 30. When the paper head of the paper passes through the strong adsorption area 321 on the paper feeding side, it is instantaneously adsorbed onto the drum surface and accurately positioned; when the paper is adsorbed on the printing drum 30 and rotates with the drum to the lower part of the print head assembly 40, the print head assembly 40 performs single-sided printing on the paper. When the paper after single-sided printing rotates with the drum to the paper separation mechanism, the paper separation mechanism acts to separate the paper adsorbed on the drum surface and then convey it to the paper receiving mechanism 20;

[0055] During double-sided printing, the paper separation mechanism acts alternately; when performing front-side printing, the paper feeding mechanism 10 transports the paper to the printing drum 30. When the paper head of the paper passes through the strong adsorption area 321 on the paper feeding side, it is instantaneously adsorbed onto the drum surface and accurately positioned; when the paper is adsorbed on the printing drum 30 and rotates with the drum to the lower part of the print head assembly 40, the print head assembly 40 performs front-side printing on the paper. When the paper after front-side printing rotates with the drum to the paper separation mechanism, the paper separation mechanism does not act. When the paper continues to rotate with the drum to the paper release area 31, the paper lifting adsorption area 511 of the paper lifting suction wheel 51 instantaneously accesses negative pressure, and the paper lifting suction wheel 51 instantaneously adsorbs the paper and lifts it to the paper temporary storage assembly 53 for temporary storage; when the detection sensor 54 detects that the paper head reaches the set position, the paper lifting adsorption area 511 of the paper lifting suction wheel 51 instantaneously disconnects the negative pressure, and at the same time, the paper feeding adsorption area 521 of the paper returning suction wheel 52 instantaneously accesses negative pressure, and the paper returning suction wheel 52 instantaneously adsorbs the paper tail and conveys the paper to the strong adsorption area 323 on the turning side of the printing drum 30. The paper is re-adsorbed onto the printing drum surface and accurately positioned. Since then, the paper tail is converted into the paper head to complete the turning. When the paper continues to be adsorbed on the printing drum and rotates with the drum to the lower part of the print head assembly 40 again, the print head assembly 40 performs back-side printing on the paper; when the paper after double-sided printing (front and back) rotates with the drum to the paper separation mechanism, the paper separation mechanism acts to separate the paper adsorbed on the drum surface and then convey it to the paper receiving mechanism 20.

[0056] In the whole set of devices of the present invention, only one non-jaw suction drum is required as the printing drum, and the overall structure design is simple. Without a paper gripper bar row, accurate paper transfer can be achieved. Only by using two suction wheels in cooperation with the opening and closing of the electromagnetic control valve, the conversion and turning of the paper from the paper tail to the paper head can be realized. The structure design is simple, the manufacturing cost is low, and during the turning process, the paper transfer path is short from the start of leaving the printing drum to returning to the printing drum, and the turning smoothness is good, which is beneficial to improving the printing efficiency.

[0057] The above are only illustrative specific embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. Single-nozzle drum-type high-speed digital inkjet printer, comprising a paper feeding mechanism and a paper receiving mechanism, a printing drum is arranged between the paper feeding mechanism and the paper receiving mechanism, and a nozzle assembly is arranged above the printing drum; characterized in that: The printing cylinder is a toothless air-suction cylinder, the printing cylinder has a paper release area and a paper adsorption area, the paper adsorption area is a constant negative pressure area, and the paper release area is a non-negative pressure area; the printing cylinder is provided with a turning mechanism and a paper separation mechanism for separating the paper adsorbed on the surface of the cylinder, and the paper separation mechanism is connected to the paper receiving mechanism; The turning mechanism includes a paper lifting air-suction wheel, a paper returning air-suction wheel, a paper temporary storage assembly and a detection sensor; the paper lifting air-suction wheel is rotatably arranged outside the paper release area of the printing cylinder, the paper lifting air-suction wheel is provided with a paper lifting adsorption area, and the paper lifting adsorption area is an instantaneous negative pressure area; the paper returning air-suction wheel is rotatably arranged outside the paper adsorption area of the printing cylinder, the paper returning air-suction wheel is provided with a paper feeding adsorption area, and the paper feeding adsorption area is also an instantaneous negative pressure area; the paper temporary storage assembly is arranged between the paper lifting air-suction wheel and the paper returning air-suction wheel; the detection sensor is arranged at the tail of the paper temporary storage assembly; The printing cylinder includes a cylinder body, the surface of the cylinder body is provided with more than two rows of air holes, air ducts are respectively arranged in the cylinder body corresponding to each air exhaust hole, and the air ducts are communicated with the corresponding air holes; a first conduction member is arranged at the end of the cylinder body in a matching manner, the cylinder body and the first conduction member can rotate relatively, and a paper feeding side strong adsorption area, a paper feeding side holding adsorption area, a turning side strong adsorption area and a turning side holding adsorption area are sequentially formed in the first conduction member along the rotation direction of the cylinder body; when the cylinder body rotates, each air duct is respectively communicated with the corresponding area when passing through each area in sequence.

2. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, characterized in that: The negative pressure in the paper feeding side strong adsorption area and the turning side strong adsorption area is greater than the negative pressure in the paper feeding side holding adsorption area and the turning side holding adsorption area.

3. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, wherein: The covering areas of the paper feeding side strong adsorption area and the turning side strong adsorption area can respectively only cover one air duct.

4. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, characterized in that: The covering areas of the paper feeding side holding adsorption area and the turning side holding adsorption area can respectively cover at least two air ducts.

5. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, characterized in that: The paper separation mechanism is a positive pressure blowing area arranged in the first conduction member and located downstream of the paper feeding side holding adsorption area, and when the paper head of the paper passes through the positive pressure blowing area, it is instantly blown away from the surface of the cylinder.

6. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, wherein: The paper separation mechanism is a swingable separation plate, and when the separation plate swings to the surface of the cylinder, it is tangent to the cylinder body.

7. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, characterized in that: The paper separation mechanism is a swingable separation hook, and an annular groove matched with the separation hook is arranged on the circumferential surface of the cylinder body.

8. The single-nozzle drum-type high-speed digital inkjet printer according to claim 1, characterized in that: The paper lifting air-suction wheel includes a wheel body, the surface of the wheel body is provided with more than two rows of air holes, air ducts are respectively arranged in the wheel body corresponding to each air exhaust hole, and the air ducts are communicated with the corresponding air holes; a second conduction member is arranged at the end of the wheel body in a matching manner, the wheel body and the second conduction member can rotate relatively, the second conduction member is connected to a negative pressure device through a pipeline, and an electromagnetic control valve is installed on the pipeline.

9. The printing control method of the single-nozzle cylinder-type high-speed digital inkjet printer according to claim 1, characterized in that: When printing on one side, the paper feeding mechanism conveys the paper to the printing drum. When the leading edge of the paper passes through the strong adsorption area on the paper feeding side, it is instantaneously adsorbed onto the drum surface and accurately positioned. When the paper is adsorbed on the printing drum and rotates with the drum to the position below the nozzle assembly, the nozzle assembly performs one-sided printing on the paper. When the paper after one-sided printing rotates with the drum to the paper separation mechanism, the paper separation mechanism operates to separate the paper adsorbed on the drum surface and convey it to the paper receiving mechanism. When printing on both sides, the paper separation mechanism operates alternately. When printing on the front side, the paper feeding mechanism conveys the paper to the printing drum. When the leading edge of the paper passes through the strong adsorption area on the paper feeding side, it is instantaneously adsorbed onto the drum surface and accurately positioned. When the paper is adsorbed on the printing drum and rotates with the drum to the position below the nozzle assembly, the nozzle assembly performs front-side printing on the paper. When the paper after front-side printing rotates with the drum to the paper separation mechanism, the paper separation mechanism does not operate. When the paper continues to rotate with the drum to the paper release area, the paper lifting and suction wheel's paper lifting adsorption area instantaneously accesses negative pressure, and the paper lifting and suction wheel instantaneously adsorbs the paper and lifts it to the paper temporary storage assembly for temporary storage. When the detection sensor detects that the leading edge of the paper reaches the set position, the paper lifting and suction wheel's paper lifting adsorption area instantaneously disconnects the negative pressure, and at the same time, the paper returning and suction wheel's paper feeding adsorption area instantaneously accesses negative pressure. The paper returning and suction wheel instantaneously adsorbs the trailing edge of the paper and conveys the paper to the paper adsorption area of the printing drum, and the paper is re-adsorbed onto the drum surface. Since then, the trailing edge is converted into the leading edge to complete the paper turning. When the paper continues to be adsorbed on the printing drum and rotates with the drum to the position below the nozzle assembly again, the nozzle assembly performs back-side printing on the paper. When the paper after both front and back printing rotates with the drum to the paper separation mechanism, the paper separation mechanism operates to separate the paper adsorbed on the drum surface and convey it to the paper receiving mechanism.

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