CN111845073A

CN111845073A - Printing apparatus and method

Info

Publication number: CN111845073A
Application number: CN202010762640.1A
Authority: CN
Inventors: 谢永林
Original assignee: Shanghai Riefa Digital Technology Co ltd
Current assignee: Shanghai Riefa Digital Technology Co ltd
Priority date: 2020-08-06
Filing date: 2020-08-06
Publication date: 2020-10-30

Abstract

The application proposes a printing apparatus comprising: an ink cartridge for providing ink; the ink-jet printing head at least comprises two printing units, the printing units are arranged along a first direction, and each printing unit is respectively connected with the ink box through a channel; a printing medium disposed opposite the inkjet print head; a print driving device that controls the inkjet print head to print on a print medium; a motion control device for controlling the relative motion of the ink jet print head and the printing medium along the horizontal direction; and an image processing device that transmits image information to be printed to the print driving device. According to the printing equipment, the ink-jet printing head is divided into the plurality of printing units, and each printing unit supplies ink independently, so that the ink pressure borne by each printing unit is basically consistent, the ink tracks are basically consistent when the side-jet printing is carried out, and the printing quality is improved.

Description

Printing apparatus and method

Technical Field

The invention relates to the technical field of ink-jet printing, in particular to printing equipment and a method.

Background

Ink jet printing is typically accomplished with drop-on-demand or continuous ink jet printing. In drop-on-demand ink-jet printing, droplets are ejected onto a recording medium using a droplet ejector with a pressurizing (e.g., thermal or piezoelectric) actuator. Selectively activating the actuator causes a flying ink drop to be formed and ejected that passes through the space between the printhead and the recording medium and impacts the recording medium. The formation of the printed image is achieved by controlling the formation of each drop as required to print the desired image. The desired image may include any dot pattern corresponding to the image data. It may include graphical or textual images. It may also include a dot pattern or three-dimensional structure for printing the functional utility device if a suitable ink is used. The ink may comprise a colored ink, such as cyan, magenta, yellow or black. Alternatively, the ink may include a conductive material, a dielectric material, a magnetic material, or a semiconductor material for functional printing. The ink may also include biological, chemical, or medical materials.

During drop ejection, the movement of the recording medium relative to the printhead may be: holding the print head stationary while the recording medium advances past the print head as the droplets are ejected; or the recording medium may be held stationary while the printhead is moved. The former motion configuration is suitable if the array of drop ejectors on the printhead can cover the entire print region of interest across the width of the recording medium. Such printheads are sometimes referred to as pagewidth printheads. A second type of printer architecture is a carriage printer, in which the printhead drop ejector array is smaller than the extent of the print region of interest on the recording medium, and the printhead is mounted on a carriage. In the carriage printer, the recording medium is advanced by a given distance in the medium advance direction and then stopped. While the recording medium is stopped, the printhead, carrying orifices that are ejecting droplets, moves in a carriage scan direction that is substantially perpendicular to the media advance direction. After a print head mounted on the carriage simultaneously prints a strip of an image across the print medium, the print medium is advanced; then the direction of movement of the carriage is reversed; the printed image is thus formed band by band.

In an actual printing process, ink droplets ejected from the print head are not necessarily vertically downward, for example, in the case shown in fig. 1, the inkjet print head 1 ejects ink droplets laterally toward the side of the print medium 7, and the trajectory of the ink droplets ejected is bent to some extent under the influence of gravity, but because the print head has a certain height H, the lower nozzle hole is pressed by ink from above, and the larger pressure of the lower nozzle hole makes the trajectory of the ink droplets ejected from the lower nozzle hole bend to a lesser extent than the trajectory of the ink droplets ejected from the upper nozzle hole, resulting in poor quality of the printed pattern. In addition, the larger pressure of the lower nozzle makes the lower nozzle easy to generate ink overflow in the printing process, resulting in poor quality of printed patterns. Because the printing head has a certain height H and is influenced by gravity, the upper spray hole has lower ink pressure than the lower spray hole, ink break is easily generated in the printing process, and the quality of printed patterns is poor.

Disclosure of Invention

The application proposes a printing apparatus comprising:

an ink cartridge for providing ink;

the ink-jet printing head at least comprises two printing units, the printing units are arranged along a first direction, and each printing unit is respectively connected with the ink box through a channel;

a printing medium disposed opposite the inkjet print head;

a print driving device that controls the inkjet print head to print on a print medium;

a motion control device for controlling the relative motion of the ink jet print head and the printing medium along the horizontal direction;

and an image processing device that transmits image information to be printed to the print driving device;

wherein, the first direction and the horizontal direction have a first included angle.

According to the printing equipment, the ink-jet printing head is divided into the plurality of printing units, and each printing unit supplies ink independently, so that the ink pressure borne by each printing unit is basically consistent, the ink tracks are basically consistent when the side-jet printing is carried out, and the printing quality is improved.

Drawings

FIG. 1 is a schematic side-view diagram of a conventional inkjet printing;

FIG. 2 is a schematic diagram of a printing apparatus according to an embodiment;

FIG. 3 is a block diagram of a printing apparatus according to an embodiment;

FIG. 4 is a diagram of the relative position of an inkjet printhead to a print medium;

FIG. 5 is a schematic diagram of an arrangement of printing units;

FIG. 6 is a schematic view of the arrangement of nozzles;

FIG. 7 is a block diagram of a printing apparatus according to an embodiment;

FIG. 8 is a block diagram of a printing apparatus according to an embodiment;

fig. 9 is a diagram showing a relative positional relationship between the ink jet print head and the print medium.

Detailed Description

In the description of this patent, it is noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention; the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, as they may be fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The meaning of the above terms in this patent may be specifically understood by those of ordinary skill in the art.

Referring to fig. 2, the printing apparatus includes an inkjet print head 1, a motion control device 3 and a print driving device 2, the print driving device 2 controls the inkjet print head 1 to print on the print medium 7, and the motion control device 3 controls the inkjet print head 1 to move relative to the print medium along a first direction perpendicular to the length direction and controls the print medium to move along the length direction. The ink jet printing apparatus further comprises image processing means 5, the image data source 4 providing image data signals to be printed, which image data signals are translated by the image processing means 5 into image information. The term "image" is meant herein to include any dot pattern specified by an image material. It may include graphical or textual images. It may also include various dot patterns suitable for printing functional devices or three-dimensional structures with suitable inks. The motion control device 3 feeds back the position of the inkjet printhead 1 and the position information of the printing medium 7 to the print driving device 2 in real time. The print driving device 2 sends an output signal to the electric pulse source 6 according to the image information provided by the image processing device 5, and the electric pulse source 6 sends an electric pulse waveform to the inkjet print head 1, so that the inkjet print head 1 ejects ink droplets. The print driving device 2 indicates when the inkjet print head starts printing and when the inkjet print head finishes printing according to the position of the inkjet print head 1 and the information of the print medium 7, and controls the inkjet print head 1 to print in a full range according to the pattern to be printed.

Referring to fig. 3, the printing apparatus includes an ink cartridge 8 and an inkjet printhead 1. The ink cartridge 8 is filled with ink, the inkjet printhead includes 4 printing units, namely a first printing unit 51, a second printing unit 52, a third printing unit 53 and a fourth printing unit 54, the four printing units are arranged along the first direction 45, each printing unit is communicated with the ink in the ink bottle through a channel 60, and the channel 60 can be a hard pipeline or a flexible pipeline. The printing medium 7 is disposed opposite to the inkjet print head 1, and the printing medium 7 and the print head 1 are relatively moved in a horizontal direction 46. The surface to be printed 71 of the printing medium 7 is perpendicular to the horizontal direction 46 in the direction of gravity. The first direction 45 is also along the direction of gravity, perpendicular to the horizontal direction 46, so that each printing unit in the inkjet print head is at an equal distance from the print medium 7. In other embodiments, the first direction 45 and the horizontal direction 46 may be at any angle. When the ink-jet printing head is used for printing, ink is ejected on the printing medium, the trajectory of the ejected ink is arc-shaped under the action of gravity, each printing unit supplies ink respectively, the pressure applied when the ink is ejected is basically consistent in one printing unit, and the ejection trajectories of the ink are also basically consistent, so that the printing quality can be effectively improved, and the printing problem caused by the inconsistent ink trajectories is avoided. The print driving means, the motion control means and the image processing means shown in fig. 2 are not shown in fig. 3, and may be integrated in the inkjet print head or may be separately present outside the inkjet print head, which will not hinder the understanding of the claimed solution. Further, as will be appreciated by those skilled in the art, a plurality of ink jet print heads may be used to increase the printing speed, which may be arranged in one or more columns along direction 46, and the features of each ink jet print head may be consistent with those described above.

Fig. 4 is a side view of the inkjet print head 1 and the print medium 7, the first direction 45 and the horizontal direction 46 having an angle θ, as shown in fig. 4a, of 0 ° < θ <90 °, the inkjet print head 1 printing the print medium 7 relatively obliquely. As shown in fig. 4b, the angle θ may be 90 °, and the print head is relatively parallel to the print medium, which is understood to be a preferred embodiment.

In the embodiment of the present invention, each print head includes at least two print units, and fig. 5 illustrates an arrangement of 2 print units by taking an inkjet print head 1 as an example. As shown in fig. 5a, the inkjet printhead 1 includes three printing units 10, the printing units 10 being arranged along a first direction 45. The inkjet printhead 1 communicates 3 color inks c1, c2, and c3, and each printing unit 10 communicates one color ink. c1, c2 and c3 may be any color, for example, c1 is magenta ink, c2 is cyan ink, c3 is yellow ink, and c1, c2 and c3 may be the same color ink, for example, black. Fig. 5b shows a case of four printing units, the four printing units 10 being arranged along the first direction 45. The first printer head 1 communicates 4 colors of ink c1, c2, c3, and c4, and each printing unit 10 communicates one color of ink. c1, c2, c3 and c4 may be any color, for example, c1 is magenta ink, c2 is cyan ink, c3 is yellow ink, c4 is black ink, and c1, c2 and c3 may also be the same color ink, for example, black. The above two cases of printing units are taken as examples, and the present invention also includes more printing units arranged in other manners.

Each printing unit in the inkjet printhead includes a plurality of orifices, and fig. 6 shows an arrangement of four orifices. As shown in fig. 6a, the printing unit 10 includes 6 nozzles 100 arranged in a row along the first direction 45, which are respectively marked with 1, 2, 3, 4, 5 and 6, and the 6 nozzles are arranged in a row according to the mark number. As shown in fig. 6b, the nozzles are aligned in a row along direction 47, and the direction 47 forms an angle with the first direction 45. As shown in fig. 6c, the printing unit 10 includes two rows of orifices 100 arranged along the first direction 45. The two rows of orifices are spaced apart from each other along the horizontal direction 46 and are arranged crosswise along the first direction 45 at 1/2 center-to-center distances between adjacent orifices. Each column includes 4 orifices, with the orifices of the first column labeled 11, 12, 13, and 14, respectively, and the orifices of the second column labeled 21, 22, 23, and 24, respectively. As shown in fig. 6d, the printing unit 10 includes a plurality of orifices 100 arrayed along a two-dimensional region (dotted line in the figure) having a length L in the direction 11 greater than a width W in the horizontal direction 46 perpendicular to the first direction 45. The orifices are arranged in 4 rows along direction 11, each row including 3 orifices, wherein the orifices in the first row are labeled 11, 12 and 13, respectively, the orifices in the second row are labeled 21, 22 and 23, respectively, the orifices in the third row are labeled 31, 32 and 33, respectively, and the orifices in the fourth row are labeled 41, 42 and 43, respectively. The orifices with the same sign mantissas are arranged in a row, and the direction of the row forms an angle with the horizontal direction 46. The above-mentioned nozzle hole arrangement modes of four cases are shown, and it can be understood by those skilled in the art that other types of nozzle hole arrangement modes are also applicable to the applied technical solution, and the number of nozzle holes is not limited to the illustrated technical solution, and may be any other number.

Referring to fig. 7, a switch control valve 90 is disposed on a channel between the printing unit and the ink bottle, a first end 91 of the switch control valve 90 is communicated with the printing unit 10, a second end 92 of the switch control valve 90 is communicated with the ink cartridge 8, and a liquid pressure of the second end 92 is greater than a liquid pressure of the first end 91; when the liquid pressure at the first end 91 of the on-off control valve 90 is less than the first threshold pressure, the on-off control valve 90 is in an open state, and ink flows from the ink cartridge 8 to the printing unit 10; when the liquid pressure at the first end 91 of the on-off control valve 90 is greater than the first threshold pressure, the on-off control valve 90 is in a closed state, the ink stops flowing from the ink cartridge 8 to the printing unit 10, the on-off control valve 90 can only conduct the ink in one direction, and the on-off control valve 90 may be an ink bag. The first threshold pressure is lower than an ambient air pressure outside the printing device. The ink box 8 can be communicated with the ambient atmospheric pressure, the pressure of one end of the switch control valve 90 close to the printing head is adjustable, and the pressure of the first end 90 of the switch control valve 90 can be changed by air suction of a negative pressure system. The first threshold pressure of the on-off control valve 90 disposed on each channel 60 is the same, and the pressure at the first end 91 of each on-off control valve is also the same, so that each printing unit 10 is subjected to the same ink pressure, and in the case that the length of the printing unit along the first direction (for example, L in fig. 6 d) is less than 5cm, the ink pressure applied to the nozzle holes in each printing unit 10 is substantially the same, and the ink trajectory ejected from each nozzle hole is also substantially the same, thereby ensuring the printing quality.

In other embodiments, the same ink pressure can be applied to each printing unit by varying the height of the ink level in the ink cartridge without the need for an on-off control valve. As shown in fig. 8, the ink cartridge 8 is divided into 4 partitioned chambers, a first partitioned chamber 81, a second partitioned chamber 82, a third partitioned chamber 83, and a fourth partitioned chamber 84. The ink in each isolation chamber is the same and is connected to a common source of stable air pressure, such as ambient atmospheric pressure, such that the air pressure source in each isolation chamber is the same. The ink liquid level in each isolation cavity is different and is in a step shape in sequence. The liquid level of the ink in the isolation cavity can be controlled by a liquid level control device, and the liquid level control device can be a device with an ink pumping or feeding function, such as an ink pump. The ink height of the first isolation cavity 81 is h1, the ink height of the second isolation cavity 82 is h2, the ink height of the third isolation cavity 83 is h3, the ink height in the fourth isolation cavity 84 is h4, and h1> h2> h3> h 4. The inkjet printhead 1 includes four printing units, which are a first printing unit 51, a second printing unit 52, a third printing unit 53 and a fourth printing unit 54 from high to low along a first direction, wherein the first printing unit 51 communicates with a first isolation chamber 81, the second printing unit 82 communicates with the second isolation chamber 52, the third printing unit 53 communicates with a third isolation chamber 83, the fourth printing unit 54 communicates with a fourth isolation chamber 84, and one printing unit corresponds to one isolation chamber. The length of the first printing unit 51 along the first direction 45 is L1, the length of the second printing unit 52 is L2, the length of the third printing unit 53 is L3, and the length of the fourth printing unit 54 is L4. The h1-h 2-L1, h2-h 3-L2, and h3-h 4-L3 can be used. The length of each printing unit can be equal, namely L1-L2-L3-L4, and the ink height difference in the adjacent separation cavities is also equal. Therefore, each printing unit is subjected to the same ink pressure, and the ink tracks sprayed out of each spray hole are basically consistent, so that the printing quality is ensured.

The printing device proposed by the present application can also be applied to the situation shown in fig. 9, and the characteristics of the inkjet printhead and the printing medium shown in fig. 9a are consistent with the above-described embodiments, and redundant explanation is not provided here. In fig. 9b, the inkjet printhead 1 is along the first direction 45, the surface 1 to be printed of the printing medium 7 is also along the first direction 45, and the first direction 45 forms an angle with the direction of gravity. The normal K of the surface to be printed is along the direction 48, and the direction 48 has a third angle with the horizontal direction 46, where the third angle is 0-90 degrees (the situation shown in fig. 9a when the angle is 0). The surface to be printed of the printing medium may be a curved surface, as shown in fig. 9c, the inkjet print head 1 is disposed along a first direction 45, the first direction 45 is parallel to the gravity direction, and the surface to be printed 71 of the printing medium 7 is a curved surface facing the inkjet print head 1. A normal of a point 0 on the curved surface on the surface to be printed 71 is along the direction 48, and the direction 48 and the horizontal direction 36 have a third included angle, where the third included angle is 0 to 90 degrees. Fig. 9d differs from fig. 9c in that the ink jet print heads 1 are arranged along a first direction 45, the first direction 45 being at an angle to the direction of gravity, and the other features are identical to fig. 9 c.

Correspondingly, the present application further provides a printing method, which adopts the printing apparatus according to any of the above embodiments, including:

the image processing device transmits image information to be printed to the print driving device;

the motion control device controls the printing medium and the ink-jet printing nozzle to move relatively along the horizontal direction;

the printing driving device controls the ink jet printing head to eject ink to the printing medium for printing.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A printing apparatus, comprising:

an ink cartridge for providing ink;

a printing medium disposed opposite the inkjet print head;

2. The printing apparatus of claim 1, wherein the first included angle is 90 degrees.

3. The printing apparatus of claim 1, wherein each of said printing units comprises at least one column of orifices, said orifices being aligned along said first direction.

4. The printing apparatus of claim 1, wherein each of said printing units comprises at least one row of orifices, and said orifices are arranged at a second angle to said first direction.

5. The printing apparatus of claim 1, wherein each of said printing units comprises a plurality of orifices arranged in a two-dimensional region, a length direction of said two-dimensional region being parallel to said first direction.

6. The printing apparatus according to claim 1, wherein a normal direction of a surface to be printed of the printing medium has a third angle with a horizontal direction.

7. The printing apparatus of claim 6, wherein the third angle is 0 degrees and all of the printing units are at the same distance from the surface to be printed of the printing medium.

8. The printing apparatus according to claim 1, wherein each of the channels is provided with an on-off control valve, a first end of the on-off control valve is communicated with the printing unit, a second end of the on-off control valve is communicated with the ink cartridge, and the liquid pressure of the second end is greater than that of the first end; when the liquid pressure at the first end of the on-off control valve is smaller than a first threshold pressure, the on-off control valve is in an open state, and ink flows from the ink box to the printing unit; when the liquid pressure at the first end of the on-off control valve is greater than the first threshold pressure, the on-off control valve is in a closed state, and ink stops flowing from the ink box to the printing unit.

9. The printing apparatus of claim 8, wherein the first threshold pressure is lower than an ambient air pressure outside the printing apparatus, and the first threshold pressure of the on-off control valve provided on each of the channels is the same.

10. The printing apparatus of claim 1, wherein said ink cartridge includes a plurality of isolated chambers, one isolated chamber being connected to one of said channels.

11. The printing apparatus of claim 10, wherein the ink in the plurality of isolated chambers of the ink cartridge is the same.

12. The printing apparatus of claim 10, further comprising a level control device that controls a level of ink in a plurality of isolated chambers of the ink cartridge.

13. The printing apparatus of claim 10, wherein the number of isolated chambers is equal to or greater than the number of printing units.

14. The printing apparatus of claim 10 wherein a source of stabilizing air pressure is in communication with the ink chamber above the ink level of the plurality of isolated chambers of the ink cartridge.

15. The printing apparatus of claim 14, wherein the pressure of the source of stabilizing air pressure is the same above the ink level of the plurality of isolated chambers of the ink cartridge.

16. The printing apparatus of claim 10, wherein the ink levels in the plurality of compartments of the ink cartridge are stepped.

17. The printing apparatus of claim 10, wherein the difference in height of the ink levels in adjacent two of said isolated chambers is equal.

18. The printing apparatus of claim 10, wherein a difference in height of two adjacent printing units in the direction of gravity is equal to a difference in height of ink levels in the respective two isolated chambers.

19. The printing apparatus of claim 1, wherein a length of each of the printing units along the first direction is less than 5 cm.

20. A printing method based on the printing apparatus of claims 1-19, comprising: