Gripping-free drum-type single-nozzle digital inkjet printer and printing control method

Abstract

The present invention discloses a gripper-free roller-type single-nozzle digital inkjet printer and a printing control method. The gripper-free roller-type single-nozzle digital inkjet printer includes a paper feed unit and a paper delivery unit. A printing paper transfer unit is provided downstream of the paper feed unit. The printing paper transfer unit is a gripper-free paper transfer unit including at least one gripper-free suction roller. An inkjet head is provided above the printing paper transfer unit. A paper support is provided on the output side of the printing paper transfer unit. A paper turning suction wheel is provided downstream of the paper support, forming a paper turning gap between the paper support and the paper turning suction wheel. A paper delivery suction wheel is provided downstream of the paper turning suction wheel. The paper turning suction wheel rotates in the opposite direction to the paper delivery suction wheel and the gripper-free suction roller. The present invention utilizes the alternating operation of the paper turning suction wheel and the paper delivery suction wheel to turn or output the paper, thereby achieving single-sided or double-sided printing operations. The overall machine has a simple structural design, stable and reliable operation, small space occupation, and low manufacturing cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of inkjet printing machinery, and in particular relates to a gripper-free roller-type single-nozzle 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] Most existing sheet-fed digital inkjet printers use rollers to carry and transfer paper. Paper is transferred between units via a print roller, a transfer roller, or a gripper bar on a conveyor chain. The print roller carries the paper for printing, and an inkjet head is positioned above it. When the paper rotates with the print roller and passes beneath the inkjet head, the inkjet head prints on the paper. While rollers with gripper bars offer high paper positioning accuracy, they also come with high manufacturing costs, complex mounting structures, a high rate of gripper bar failure, and a tendency for gripper marks to remain on the paper, compromising the integrity of printed products.

[0004] Furthermore, existing inkjet printers typically use two separate inkjet systems to print on the front and back of a sheet of paper. However, the cost of these two systems is high. Achieving high-precision printing while minimizing equipment costs has always been a challenge. 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 gripper-free drum single-nozzle digital inkjet printer that can achieve precise paper transfer without a gripper row, can achieve single-sided printing or double-sided printing of a single sheet of paper using a single set of nozzles, and has low equipment cost.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: a gripper-free roller-type single-nozzle digital inkjet printing machine, comprising a paper feeding unit and a paper receiving unit, a printing paper transfer unit is arranged downstream of the paper feeding unit, and the printing paper transfer unit is a gripper-free paper transfer unit including at least one gripper-free suction roller; an inkjet head is arranged above the printing paper transfer unit, a paper support plate is arranged on the output side of the printing paper transfer unit, a paper turning suction wheel is arranged downstream of the paper support plate, and a paper turning gap is formed between the paper support plate and the paper turning suction wheel; a paper receiving suction wheel is arranged downstream of the paper turning suction wheel, and the rotation direction of the paper turning suction wheel is opposite to that of the paper receiving suction wheel and the gripper-free suction roller; the paper turning suction wheel is used to turn the paper head and the paper tail of the paper over and return them to the printing paper transfer unit, and the paper receiving suction wheel is used to convey the printed paper to the paper receiving unit.

[0007] As a preferred technical solution, the tooth-free suction roller includes a roller body, the surface of the roller body is provided with more than two rows of air holes, and air ducts are respectively provided in the roller body corresponding to each exhaust hole, and the air ducts are connected with the corresponding air holes; the end of the roller body is cooperated with a first conductive part, the roller body and the first conductive part can rotate relative to each other, and a strong adsorption area is formed in the first conductive part; when the roller body rotates, each air duct passes through the strong adsorption area in turn and is connected with the strong adsorption area, and when the paper head passes through the strong adsorption area, it is instantly adsorbed to the roller surface and precisely positioned.

[0008] As a preferred technical solution, the printing and paper feeding unit includes two gripper-free suction rollers, a printing platform is provided between the two gripper-free suction rollers, and the inkjet head is located above the printing platform.

[0009] As a preferred technical solution, the printing platform is provided with a paper holding mechanism for holding the paper on the platform surface.

[0010] As a preferred technical solution, the paper holding mechanism is a negative pressure adsorption mechanism or a paper pressing mechanism.

[0011] As an optional technical solution, the printing and paper transfer unit is a tooth-free suction roller.

[0012] As a preferred technical solution, the paper-turning and suction wheel includes a wheel body, the surface of the wheel body is provided with more than two rows of air holes, and the wheel body is provided with air ducts corresponding to each exhaust hole, and the air ducts are connected to the corresponding air holes; the end of the wheel body is provided with a second conductive part, the wheel body and the second conductive part can rotate relative to each other, the second conductive part is connected to the negative pressure device through a pipeline, and an electromagnetic control valve is installed on the pipeline.

[0013] The present invention also provides a printing control method using the above-mentioned gripper-free drum-type single-nozzle digital inkjet printer:

[0014] During single-sided printing, the paper feeding unit conveys the paper to the printing and paper feeding unit, which includes at least one gripper-free suction roller. The paper is instantly adsorbed to the surface of the suction roller and precisely positioned. When the paper is conveyed to the bottom of the inkjet head by the suction roller, the inkjet head prints single-sided printing on the paper. After single-sided printing, the paper continues to be conveyed downstream by the suction roller. At this time, the paper turning suction wheel is in an idle state with suction turned off, while the paper collection suction wheel is in a working state with suction turned on. The paper output from the suction roller is sucked by the suction wheel and conveyed to the paper collection unit.

[0015] During double-sided printing, the paper turning suction wheel and the paper receiving suction wheel work alternately; during front-side printing, the paper feeding unit conveys the paper to the printing and paper feeding unit, and the paper is instantly adsorbed to the surface of the suction roller and accurately positioned; when the paper is conveyed to the bottom of the inkjet head with the suction roller, the inkjet head prints single-sided paper on the paper, and after completing single-sided printing, the paper continues to be conveyed downstream with the suction roller. At this time, the paper turning suction wheel is in the working state of turning on the suction, while the paper receiving suction wheel is in the idling state of turning off the suction. The paper turning suction wheel will suck the tail of the paper output from the suction roller, Because the paper turning suction wheel rotates in the opposite direction, the tail of the paper is converted into the head of the paper and the turning is completed. The paper is transferred from the paper turning gap and then returned to the printing and paper feeding unit; the paper continues to be adsorbed on the suction roller and when it rotates again to the bottom of the inkjet head with the suction roller, the inkjet head prints on the back of the paper; after completing the double-sided printing, the paper continues to be transported downstream with the suction roller. At this time, the paper turning suction wheel is in an idling state with the suction turned off, and the paper collection suction wheel is in a working state with the suction turned on. The paper collection suction wheel will suck the paper output from the suction roller and transfer it to the paper collection unit.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] (1) By adopting a gripper-free suction roller as the paper transfer unit during printing, when the paper head of a single paper reaches the strong adsorption area, the paper head is subjected to a large negative pressure adsorption effect, and will be instantly adsorbed to the surface of the roller and accurately positioned, playing the role of gripper handover; in this way, there is no need to set up a paper gripper row in the entire equipment. Compared with the traditional roller with a paper gripper row, the gripper-free suction roller does not require a large diameter and has a simple structural design. It not only greatly reduces the manufacturing cost of the equipment, but also maintains high-precision positioning of the paper during printing operation. There are no gripper marks on the paper, which ensures the integrity of the printed product. At the same time, the paper transfer is stable and there are no fault nodes, which facilitates the high-speed and smooth transfer of paper.

[0018] (2) By adopting a single set of inkjet heads, that is, a single set of inkjet systems, the paper is turned over or output by using the paper turning suction wheel and the paper collecting suction wheel to work alternately, thereby realizing single-sided printing or double-sided printing operations. The structural design is simple, the operation is stable and reliable, the space occupied is small, the manufacturing cost is low, and it has broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following drawings are intended only to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0020] Figure 1 It is a structural diagram of embodiment 1 of the present invention;

[0021] Figure 2 This is a structural diagram of a tooth-free suction drum according to an embodiment of the present invention;

[0022] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure along the AA direction;

[0023] Figure 4 This is a reference diagram of the paper transfer status at the printing paper transfer unit (the paper holding mechanism is a negative pressure adsorption mechanism);

[0024] Figure 5 This is a reference diagram of the paper transfer status at the printing paper transfer unit (the paper holding mechanism is a paper pressing mechanism);

[0025] Figure 6 This is a schematic structural diagram of the paper turning and suction wheel in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of paper conveyance during single-sided printing according to the first embodiment of the present invention;

[0027] Figure 8 This is a schematic diagram of paper conveyance during double-sided printing according to the first embodiment of the present invention;

[0028] Figure 9 It is a structural diagram of embodiment 2 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and examples. In the following detailed description, certain exemplary embodiments of the present invention are described by way of illustration only. It is understood that those skilled in the art will recognize that the described embodiments may be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the drawings and description are illustrative in nature and are not intended to limit the scope of the claims.

[0030] Example 1

[0031] like Figure 1 As shown, the gripper-free roller-type single-nozzle digital inkjet printer includes a paper feeding unit 1 and a paper receiving unit 2. A printing and paper transfer unit 3 is provided downstream of the paper feeding unit 1, an inkjet head 4 is provided above the printing and paper transfer unit 3, a paper support board 5 is provided on the output side of the printing and paper transfer unit 3, a paper turning suction wheel 6 is provided downstream of the paper support board 5, and a paper turning gap 7 is formed between the paper support board 5 and the paper turning suction wheel 6; a paper receiving suction wheel 8 is provided downstream of the paper turning suction wheel 6, and a paper guide board 10 is provided on the output side of the paper turning suction wheel 6 below the paper turning gap 7.

[0032] In this embodiment, the printing and paper feeding unit 3 includes two tooth-free suction rollers, which are defined as the first suction roller 31 and the second suction roller 32 for the convenience of description. A printing platform 33 is provided between the first suction roller 31 and the second suction roller 32, and the inkjet head 4 is located above the printing platform 33.

[0033] The printing platform 33 is provided with a paper holding mechanism for holding the paper on the platform surface. Figure 4 The paper holding mechanism is preferably a negative pressure adsorption mechanism. When the paper 9 is transferred from the first suction roller 31 to the second suction roller 32, the paper 9 is always kept on the surface of the printing platform 33 by a slight negative pressure adsorption method, thereby preventing the paper from warping and effectively ensuring the printing accuracy and quality. Of course, reference Figure 5 The paper holding mechanism can also be a paper pressing mechanism 34 such as a paper pressing roller, a paper pressing wheel or a paper pressing belt arranged at both ends of the printing platform 33. When the paper 9 is transferred from the first suction roller 31 to the second suction roller 32, the paper 9 is always kept on the surface of the front printing platform 33 through the paper pressing mechanism 34.

[0034] The structure of the tooth-free suction roller is described below using the first suction roller 31 as an example. Figure 2 and Figure 3 The tooth-free suction roller includes a roller body 311, and a plurality of rows of air holes 312 are provided on the surface of the roller body 311. The air holes 312 in the same row are evenly distributed along the axial direction of the roller body 311, and the air holes 312 in different rows are distributed in an annular manner along the circumference of the roller body 311; an air duct 313 is provided in the roller body 311 corresponding to each air exhaust hole 312, and the air duct 313 is connected to the corresponding air hole 312, and each air duct 313 is located on the same circumference; the end of the roller body 311 is provided with a first conducting member 314, and the roller body 31 1 can rotate relative to the first conductive member 314, and a strong adsorption area is formed in the first conductive member 314; when the drum body 311 rotates, each air duct 313 passes through the strong adsorption area in sequence and is connected to the strong adsorption area. The coverage area of ​​the strong adsorption area is preferably only 1 to 3 air ducts, and the negative pressure value is preferably 60 to 100 kPa; in this way, the air holes corresponding to the air ducts rotated to the strong adsorption area will instantly adsorb the paper arriving there, playing a "biting" role. The paper is subjected to a large negative pressure adsorption effect, and will be instantly adsorbed to the drum surface and accurately positioned.

[0035] The rotation direction of the paper turning suction wheel 6 is opposite to that of the paper collecting suction wheel 8, the first suction roller 31, and the second suction roller 32; Figure 6The paper turning and suction wheel 6 includes a wheel body 61, and the surface of the wheel body 61 is provided with more than two rows of air holes. The wheel body 61 is provided with air ducts corresponding to each exhaust hole, and the air ducts are connected to the corresponding air holes; the end of the wheel body 61 is provided with a second conductive member 62, and the wheel body 61 and the second conductive member 62 can rotate relative to each other. The second conductive member 62 is connected to the negative pressure device through a pipeline, and an electromagnetic control valve is installed on the pipeline, so that a suction area 63 that can be turned on and off is formed in the second conductive member 62; when the wheel body 61 rotates, each air duct passes through the suction area in turn and is connected to the suction area, and the negative pressure on and off state of the suction area 63 can be controlled by high-frequency opening and closing of the electromagnetic control valve.

[0036] The paper collecting suction wheel 8 is located downstream of the paper turning suction wheel 6 and is arranged side by side. The structural principle of the paper collecting suction wheel 8 is the same as that of the paper turning suction wheel 6, which will not be described in detail here.

[0037] The specific printing control method is as follows:

[0038] refer to Figure 7 When printing on one side, the paper feeding unit 1 conveys a single sheet of paper 9 to the first suction roller 31. When the paper head reaches the strong adsorption area of ​​the first suction roller 31, the paper head is instantly adsorbed to the roller surface and accurately positioned; as the first suction roller 31 continues to rotate, the paper head gradually leaves the strong adsorption area and enters the printing platform 33. The inkjet head 4 above the printing platform 33 performs high-precision printing on the paper. Driven by the first suction roller 31, the paper gradually reaches the second suction roller 32 along the surface of the printing platform 33. When the paper head reaches the strong adsorption area of ​​the second suction roller 32, , the paper head is once again instantly adsorbed onto the drum surface and accurately positioned, thus completing the paper transfer of the single-sided printing operation; the paper after completing single-sided printing continues to be transported downstream along the supporting board 5 driven by the second suction drum 32 (in order to prevent the paper from floating, a blower mechanism such as a fan can be provided above the supporting board 5). At this time, the paper turning suction wheel 6 is in an idling state with suction turned off, which will not hinder the paper from being transported downstream, and the paper delivery suction wheel 8 is in a working state of suction turned on. When the paper reaches the adsorption area of ​​the paper delivery suction wheel 8, the paper delivery suction wheel 8 will absorb the paper output from the second suction drum 32 and transport it to the paper delivery unit 2;

[0039] refer to Figure 8When double-sided printing is performed, the paper turning suction wheel 6 and the paper receiving suction wheel 8 work alternately; when printing on the front side, the paper feeding unit 1 conveys the single paper 9 to the first suction roller 31. When the paper head reaches the strong adsorption area of ​​the first suction roller 31, the paper head is instantly adsorbed to the roller surface and accurately positioned; as the first suction roller 31 continues to rotate, the paper head gradually leaves the strong adsorption area and enters the printing platform 33. The inkjet head 4 above the printing platform 33 performs high-precision printing on the front side of the paper. Driven by the first suction roller 31, the paper gradually reaches the second suction roller 32 along the surface of the printing platform 33. When the paper head reaches the strong adsorption area of ​​the second suction roller 32, the paper head is again instantly adsorbed to the roller surface and accurately positioned, thus completing the paper transfer for the front side printing operation; the paper after the front side printing is completed continues to be conveyed downstream along the second suction roller 32. When the paper tail reaches the adsorption area of ​​the paper turning suction wheel 6, the paper turning suction wheel 6 sucks the paper tail output from the second suction roller 32. Because the paper turning suction wheel 6 rotates in the opposite direction, the paper tail is converted into the paper head and the turning is completed. The paper is brought into the paper guide 10 from the paper turning gap 7, and then returns to the printing paper feeding unit after being transferred; the paper continues to be adsorbed on the suction roller and rotates again to the bottom of the inkjet head 4 with the suction roller, and the inkjet head 4 prints on the back of the paper; the paper after completing the double-sided printing continues to be transported downstream with the suction roller. At this time, the paper turning suction wheel 6 is in the idle state with the suction turned off, and the paper receiving suction wheel 8 is in the working state of starting the suction. When the paper reaches the adsorption area of ​​the paper receiving suction wheel 8, the paper receiving suction wheel 8 sucks the paper output from the suction roller and transfers it to the paper receiving unit.

[0040] It should be noted that the paper that has completed front-side printing returns to the printing and paper transfer unit in a variety of ways, such as using a suction wheel, a suction belt, a paper feed belt, or a suction roller for transition. The specific transfer method and transfer path can be easily implemented by those skilled in the art, and will not be elaborated here. They should all fall within the scope of protection of the present invention.

[0041] Example 2

[0042] refer to Figure 9The structural principles of this embodiment are basically the same as those of the first embodiment, with the difference being that in this embodiment, the printing paper transfer unit 3 is a gripper-free suction roller. At this time, the inkjet head 4 is arranged above the gripper-free suction roller. When the paper is adsorbed on the surface of the roller, the inkjet head 4 performs the printing operation. Setting up a gripper-free suction roller in this way can reduce the number of rollers, but the diameter of the roller needs to be increased accordingly. In this embodiment, the paper that has completed front-side printing is returned to the printing paper transfer unit 3 by directly transferring it back to the gripper-free suction roller. Of course, it can also be achieved by other transfer methods and paths such as a suction wheel, a suction belt, or a paper feed belt.

[0043] To sum up, the present invention adopts a gripper-free suction roller as the paper transfer unit during printing operation. When the paper head of a single paper reaches the strong adsorption area, the paper head is subjected to a large negative pressure adsorption effect, and will be instantly adsorbed to the roller surface and accurately positioned, playing the role of gripper handover; in this way, there is no need to set up a paper gripper row in the entire equipment, and the gripper-free suction roller does not require a large diameter and has a simple structural design. It not only maintains high-precision positioning of the paper during printing operation, but also greatly reduces the manufacturing cost of the equipment. At the same time, there is no fault node, which facilitates high-speed and smooth transmission of paper; by adopting a single set of inkjet heads, that is, a single set of inkjet systems, the paper turning or output is achieved by alternating the paper turning suction wheel and the paper collecting suction wheel, thereby realizing single-sided printing or double-sided printing operations, with a simple structural design, stable and reliable operation, small space occupation, low manufacturing cost, and broad market prospects.

[0044] The above description is only an illustrative embodiment of the present invention and is 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 principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A gripper-free, drum-type, single-nozzle digital inkjet printer comprising a paper feed unit and a paper delivery unit, wherein a printing and paper transfer unit is provided downstream of the paper feed unit, characterized in that: The printing and paper feeding unit is a gripper-free paper feeding unit including at least one gripper-free suction roller; an inkjet head is arranged above the printing and paper feeding unit, a paper support plate is arranged on the output side of the printing and paper feeding unit, a paper turning suction wheel is arranged downstream of the paper support plate, and a paper turning gap is formed between the paper support plate and the paper turning suction wheel; a paper collecting suction wheel is arranged downstream of the paper turning suction wheel, and the rotation direction of the paper turning suction wheel is opposite to that of the paper collecting suction wheel and the gripper-free suction roller; the paper turning suction wheel is used to turn the paper head and the paper tail of the paper over and return them to the printing and paper feeding unit, and the paper collecting suction wheel is used to convey the printed paper to the paper collecting unit; The tooth-free suction roller includes a roller body, the surface of which is provided with two or more rows of air holes, and an air duct is provided in the roller body corresponding to each exhaust hole, and the air duct is connected to the corresponding air hole; a first conductive member is provided at the end of the roller body, and the roller body and the first conductive member are relatively rotatable, and a strong adsorption area is formed in the first conductive member; when the roller body rotates, each air duct passes through the strong adsorption area in turn and is connected to the strong adsorption area, and when the paper head passes through the strong adsorption area, it is instantly adsorbed to the roller surface and accurately positioned; The paper turning and suction wheel includes a wheel body, the surface of the wheel body is provided with more than two rows of air holes, the wheel body is provided with air ducts corresponding to each exhaust hole, and the air ducts are connected with the corresponding air holes; the end of the wheel body is provided with a second conductive piece, the wheel body and the second conductive piece can rotate relative to each other, the second conductive piece is connected to the negative pressure device through a pipeline, and an electromagnetic control valve is installed on the pipeline.

2. The gripper-free drum-type single-nozzle digital inkjet printer according to claim 1, characterized in that: The printing and paper transfer unit includes two gripper-free suction rollers, a printing platform is provided between the two gripper-free suction rollers, and the inkjet head is located above the printing platform.

3. The gripper-free drum-type single-nozzle digital inkjet printer according to claim 2, characterized in that: The printing platform is provided with a paper holding mechanism for holding the paper on the platform surface.

4. The gripper-free drum-type single-nozzle digital inkjet printer according to claim 3, characterized in that: The paper holding mechanism is a negative pressure adsorption mechanism or a paper pressing mechanism.

5. The gripper-free drum-type single-nozzle digital inkjet printer according to claim 1, characterized in that: The printing and paper transfer unit is a tooth-free suction roller.

6. The printing control method of the gripper-free drum-type single-nozzle digital inkjet printer according to claim 1, characterized in that: During single-sided printing, the paper feeding unit conveys the paper to the printing and paper feeding unit, which includes at least one gripper-free suction roller. The paper is instantly adsorbed to the surface of the suction roller and precisely positioned. When the paper is conveyed to the bottom of the inkjet head by the suction roller, the inkjet head prints single-sided printing on the paper. After single-sided printing, the paper continues to be conveyed downstream by the suction roller. At this time, the paper turning suction wheel is in an idle state with suction turned off, while the paper collection suction wheel is in a working state with suction turned on. The paper output from the suction roller is sucked by the suction wheel and conveyed to the paper collection unit. During double-sided printing, the paper turning suction wheel and the paper receiving suction wheel work alternately; during front-side printing, the paper feeding unit conveys the paper to the printing and paper feeding unit, and the paper is instantly adsorbed to the surface of the suction roller and accurately positioned; when the paper is conveyed to the bottom of the inkjet head with the suction roller, the inkjet head prints single-sided paper on the paper, and after completing single-sided printing, the paper continues to be conveyed downstream with the suction roller. At this time, the paper turning suction wheel is in the working state of turning on the suction, while the paper receiving suction wheel is in the idling state of turning off the suction. The paper turning suction wheel will suck the tail of the paper output from the suction roller, Because the paper turning suction wheel rotates in the opposite direction, the tail of the paper is converted into the head of the paper and the turning is completed. The paper is transferred from the paper turning gap and then returned to the printing and paper feeding unit; the paper continues to be adsorbed on the suction roller and when it rotates again to the bottom of the inkjet head with the suction roller, the inkjet head prints on the back of the paper; after completing the double-sided printing, the paper continues to be transported downstream with the suction roller. At this time, the paper turning suction wheel is in an idling state with the suction turned off, and the paper collection suction wheel is in a working state with the suction turned on. The paper collection suction wheel will suck the paper output from the suction roller and transfer it to the paper collection unit.

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