Printing apparatus and method

Abstract

The application provides a printing device, which comprises: an ink cartridge for providing ink; at least one inkjet print head, which comprises at least two print units arranged along a first direction, and each print unit is connected to the ink cartridge through a channel; a printing medium arranged opposite to the inkjet print head; a printing driving device for controlling the inkjet print head to print on the printing medium; a motion control device for controlling the relative motion of the inkjet print head and the printing medium along a horizontal direction; and an image processing device for transmitting image information to be printed to the printing driving device. The printing device provided by the application divides the inkjet print head into multiple print units, and each print unit is independently supplied with ink, so that the ink pressure received by each print unit is basically consistent, the ink trajectory is also basically consistent during side jet printing, and the printing quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of inkjet printing, and in particular to a printing apparatus and method. BACKGROUND

[0002] Inkjet printing is typically accomplished using drop-on-demand or continuous inkjet printing. In drop-on-demand printing, drops are ejected onto a recording medium using drop ejectors with a pressurized (e.g., thermal or piezoelectric) actuator. Selective activation of the actuator causes a flying drop to be formed and ejected, which flies through the space between the printhead and the recording medium and impacts the recording medium. Formation of a printed image is accomplished by controlling the formation of each drop as needed to print the desired image. The desired image can include any dot pattern corresponding to the image data. It can include a graphic or text image. If appropriate inks are used, it can also include dot patterns or three-dimensional structures for printing functional devices. The inks can include colored inks, such as cyan, magenta, yellow, or black. Alternatively, the inks can include electrically conductive materials, dielectric materials, magnetic materials, or semiconductive materials for functional printing. The inks can also include biological, chemical, or medical materials.

[0003] During drop ejection, the motion of the recording medium relative to the printhead can be either to keep the printhead stationary while the recording medium is advanced past the printhead during drop ejection, or to keep the recording medium stationary while the printhead is moved. The former motion arrangement is suitable if the array of drop ejectors on the printhead can cover the entire print interest area across the width of the recording medium. Such printheads are sometimes referred to as pagewidth printheads. The second type of printer arrangement is a carriage printer, in which the printhead drop ejector array is smaller than the extent of the print interest area on the recording medium, and the printhead is mounted on a carriage. In a carriage printer, the recording medium is advanced a given distance in a media advance direction, and then stopped. While the recording medium is stopped, the carriage carrying the printhead with its drop orifices ejecting drops is moved in a carriage scan direction, which is substantially perpendicular to the media advance direction. After the printhead mounted on the carriage has traversed the print medium while printing a swath of image, the recording medium is advanced; the direction of motion of the carriage is then reversed; the printed image is thereby formed swath by swath.

[0004] In actual printing, the drops ejected by the printhead are not necessarily straight down, for example Figure 1In the shown case, the inkjet print head 1 sprays ink to the side of the print medium 7, and the trajectory of the ink droplets is curved to some extent due to the effect of gravity. However, the print head itself has a certain height H, and the ink pressure on the lower nozzles is greater than that on the upper nozzles. The greater pressure on the lower nozzles causes the trajectory of the ink droplets sprayed from the lower nozzles to be less curved than that of the ink droplets sprayed from the upper nozzles, resulting in poor print quality. In addition, the greater pressure on the lower nozzles causes ink to easily overflow during printing, resulting in poor print quality. Due to the height H of the print head itself, the ink pressure on the upper nozzles is lower than that on the lower nozzles due to the effect of gravity, and ink is easily broken during printing, resulting in poor print quality. SUMMARY

[0005] The present application provides a printing device, comprising:

[0006] an ink cartridge for providing ink;

[0007] at least one inkjet print head, the inkjet print head comprising at least two print units arranged along a first direction, each print unit being connected to the ink cartridge through a channel;

[0008] a print medium arranged opposite to the inkjet print head;

[0009] a print driving device for controlling the inkjet print head to print on the print medium;

[0010] a motion control device for controlling the relative motion of the inkjet print head and the print medium along a horizontal direction;

[0011] and an image processing device for transmitting image information to be printed to the print driving device;

[0012] wherein the first direction and the horizontal direction have a first included angle.

[0013] The printing device provided by the present application divides the inkjet print head into multiple print units, and each print unit is independently supplied with ink, so that the ink pressure on each print unit is substantially uniform, and the trajectory of the ink is also substantially uniform during side spraying, thereby improving the print quality. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Fig. 1 is a schematic diagram of the side spraying of an existing inkjet print head;

[0015] Figure 2 Fig. 2 is a schematic diagram of the printing device provided by an embodiment of the present application;

[0016] Figure 3 Fig. 3 is a structural diagram of the printing device provided by an embodiment of the present application.

[0017] Figure 4 Fig. 2 is a diagram of the relative positional relationship between the inkjet print head and the print medium;

[0018] Figure 5 Fig. 3 is a schematic diagram of the arrangement of the print units;

[0019] Figure 6 Fig. 4 is a schematic diagram of the arrangement of the ink ejection holes;

[0020] Figure 7 Fig. 5 is a structural diagram of the printing apparatus according to one embodiment;

[0021] Figure 8 Fig. 6 is a structural diagram of the printing apparatus according to one embodiment;

[0022] Figure 9 Fig. 7 is a diagram of the relative positional relationship between the inkjet print head and the print medium. DETAILED DESCRIPTION

[0023] In the description of the present patent, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present invention; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present patent can be understood according to the specific circumstances.

[0024] Please refer to Figure 2The printing apparatus comprises an inkjet printhead 1, a motion control device 3 and a print driver 2, the print driver 2 controls the inkjet printhead 1 to print on the print medium 7, the motion control device 3 controls the inkjet printhead 1 to move relative to the print medium in a first direction perpendicular to the length direction and controls the print medium to move along the length direction. The inkjet printing apparatus further comprises an image processing device 5, an image data source 4 provides image data signals of the image to be printed, the image data signals are translated into image information by the image processing device 5. The term "image" in this context means to include any dot pattern specified by the image data. It can include graphical or textual images. It can also include various dot patterns suitable for printing functional devices or three-dimensional structures, such printing requires suitable ink. The motion control device 3 feeds back the position information of the inkjet printhead 1 and the print medium 7 to the print driver 2 in real time. The print driver 2 sends output signals to the electric pulse source 6 according to the image information provided by the image processing device 5, the electric pulse source 6 sends electric pulse waveforms to the inkjet printhead 1, so that the inkjet printhead 1 ejects ink droplets. The print driver 2 further instructs the inkjet printhead when to start printing and when to end printing according to the position information of the inkjet printhead 1 and the print medium 7, and controls the printing of the inkjet printhead 1 throughout the entire printing process according to the pattern to be printed.

[0025] Please refer to Figure 3 The printing apparatus comprises an ink cartridge 8 and an inkjet printhead 1. The ink cartridge 8 contains ink, and the inkjet printhead comprises four printing units, i.e. 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 a first direction 45, and each printing unit is in communication with the ink in the ink cartridge through a channel 60, which can be a hard pipe or a soft pipe. The print medium 7 is arranged opposite to the inkjet printhead 1, and the print medium 7 and the inkjet printhead 1 move relative to each other along a horizontal direction 46. The surface 71 to be printed of the print medium 7 is perpendicular to the horizontal direction 46 along the direction of gravity. The first direction 45 is also perpendicular to the horizontal direction 46 along the direction of gravity, so that the distance between each printing unit of the inkjet printhead and the print medium 7 is equal. In other embodiments, the first direction 45 and the horizontal direction 46 can be at any angle. When the inkjet printhead prints, the ejected ink forms an arc on the print medium under the action of gravity, each printing unit supplies ink, and the pressure on the ink when it is ejected in one printing unit is basically consistent, and the trajectory of the ejected ink is also basically consistent, so that the printing quality can be effectively improved, and the printing problems caused by inconsistent ink trajectories can be avoided. Figure 2The printing drive, motion control, and image processing units shown are in Figure 3 As not shown, it can be integrated into the inkjet printhead or exist separately outside the inkjet printhead. It is understood that this will not hinder the understanding of the technical solution of the application. In addition, those skilled in the art will understand that multiple inkjet printheads can be used to improve printing speed. The inkjet printheads can be arranged in one or more columns along the 46-axis, and the characteristics of each inkjet printhead can be consistent with those described above.

[0026] Figure 4 This is a side view of the inkjet printhead 1 and the printing medium 7, where an angle θ exists between the first direction 45 and the horizontal direction 46, as shown below. Figure 4 As shown in Figure a, 0° < θ < 90°, the inkjet printhead 1 is relatively tilted when printing the printing medium 7. Figure 4 As shown in b, the included angle θ can be 90°, and the print head is relatively parallel to the printing medium. It can be understood that this is a preferred implementation method.

[0027] In embodiments of the present invention, each printhead includes at least two printing units. Figure 5 Taking an inkjet printhead 1 as an example, two arrangements of printing cells are shown. For example... Figure 5 As shown in Figure a, the inkjet printhead 1 includes three printing units 10, which are arranged along a first direction 45. The inkjet printhead 1 is connected to three colors of ink, c1, c2, and c3, with each printing unit 10 connected to one color of ink. c1, c2, and c3 can be any color; for example, c1 is magenta ink, c2 is cyan ink, and c3 is yellow ink. c1, c2, and c3 can also be the same color of ink, such as black. Figure 5 Illustration b shows a scenario with four printing units 10 arranged along a first direction 45. The first printhead 1 is connected to four colors of ink, c1, c2, c3, and c4, with each printing unit 10 connected to one color of ink. c1, c2, c3, and c4 can be any color; for example, c1 is magenta ink, c2 is cyan ink, c3 is yellow ink, and c4 is black ink. c1, c2, and c3 can also be the same color, such as black. The above examples illustrate two scenarios of printing units; this illustration also includes more printing units arranged in other ways.

[0028] Each printing unit in the inkjet printhead includes multiple nozzles. Figure 6 Four different nozzle arrangements are shown. For example... Figure 6As shown in Fig. a, the printing unit 10 includes six nozzles 100 arranged in a row along the first direction 45, which are marked as 1, 2, 3, 4, 5 and 6 respectively. The six nozzles are arranged in a row according to the mark order. As shown in Fig. Figure 6 As shown in Fig. b, the nozzles are arranged in a row, and the nozzles are arranged in a row along the direction 47, which has an angle with the first direction 45. As shown in Fig. Figure 6 As shown in Fig. c, the printing unit 10 includes two rows of nozzles 100 arranged along the first direction 45. The two rows of nozzles are spaced apart along the horizontal direction 46, and are arranged in a cross pattern with a 1 / 2 nozzle center distance along the first direction 45. Each row includes four nozzles, wherein the nozzles of the first row are marked as 11, 12, 13 and 14 respectively, and the nozzles of the second row are marked as 21, 22, 23 and 24 respectively. As shown in Fig. Figure 6 As shown in Fig. d, the printing unit 10 includes a plurality of nozzles 100 arranged along a two-dimensional region (dashed line in the figure), and the length L along the direction 11 is greater than the width W along the horizontal direction 46 perpendicular to the first direction 45. The nozzles are arranged in four rows along the direction 11, and each row includes three nozzles, wherein the nozzles of the first row are marked as 11, 12 and 13 respectively, the nozzles of the second row are marked as 21, 22 and 23 respectively, the nozzles of the third row are marked as 31, 32 and 33 respectively, and the nozzles of the fourth row are marked as 41, 42 and 43 respectively. The nozzles with the same last digit are arranged in a row, and the direction of the row has an angle with the horizontal direction 46. The above-mentioned four nozzle arrangement modes can be understood by those skilled in the art, and other types of nozzle arrangement modes are also applicable to the technical solution of the application, and the number of nozzles is not limited to the technical solution shown in the figure, and can be any other number.

[0029] Please refer to Figure 7, the channel between the printing unit and the ink bottle is provided with a switch control valve 90, the first end 91 of the switch control valve 90 is communicated with the printing unit 10, the second end 92 of the switch control valve 90 is communicated with the ink cartridge 8, the liquid pressure of the second end 92 is greater than that of the first end 91; when the liquid pressure of the first end 91 of the switch control valve 90 is less than the first threshold pressure, the switch control valve 90 is in an open state, and the ink flows from the ink cartridge 8 to the printing unit 10; when the liquid pressure of the first end 91 of the switch control valve 90 is greater than the first threshold pressure, the switch control valve 90 is in a closed state, and the ink stops flowing from the ink cartridge 8 to the printing unit 10, the switch control valve 90 can only unidirectionally conduct the ink, and the switch control valve 90 can be an ink capsule. The first threshold pressure is lower than the ambient air pressure outside the printing device. The ink cartridge 8 can be communicated with the ambient air pressure, the pressure near the end of the printing head of the switch control valve 90 is adjustable, and the pressure of the first end 90 of the switch control valve 90 can be changed by a negative pressure system. The first threshold pressure of the switch control valve 90 arranged on each channel 60 is the same, and the pressure of the first end 91 of each switch 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 (for example Figure 6 L in d) of the printing unit along the first direction is less than 5 cm, the ink pressure received by each ejection hole in the printing unit 10 is basically consistent, the ink trajectories ejected by each ejection hole are also basically consistent, and the printing quality is ensured.

[0030] In other embodiments, the switch control valve can not be needed, and the same ink pressure can be applied to each printing unit by changing the height of the ink liquid level in the ink cartridge. For example Figure 8As shown, the ink cartridge 8 is divided into four isolated chambers, which are the first isolated chamber 81, the second isolated chamber 82, the third isolated chamber 83 and the fourth isolated chamber 84. The ink in each isolated chamber is the same, and is connected to a common stable air pressure source, such as the ambient atmospheric pressure, so that the air pressure in each isolated chamber is the same. The liquid level of the ink in each isolated chamber is different, and is in a step-like arrangement. The liquid level of the ink in the isolated chamber can be controlled by a liquid level control device, which can be an ink pump or other device with ink pumping or ink feeding functions. The ink level in the first isolated chamber 81 is h1, the ink level in the second isolated chamber 82 is h2, the ink level in the third isolated chamber 83 is h3, and the ink level in the fourth isolated chamber 84 is h4, with h1>h2>h3>h4. The inkjet printhead 1 includes four printing units, which are the first printing unit 51, the second printing unit 52, the third printing unit 53 and the fourth printing unit 54, arranged in a first direction from high to low. The first printing unit 51 is connected to the first isolated chamber 81, the second printing unit 52 is connected to the second isolated chamber 82, the third printing unit 53 is connected to the third isolated chamber 83, and the fourth printing unit 54 is connected to the fourth isolated chamber 84. One printing unit corresponds to one isolated chamber, and in other embodiments, the number of isolated chambers can be greater than the number of printing units. 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 following conditions can be set: h1-h2=L1, h2-h3=L2, and h3-h4=L3. The lengths of the printing units can be equal, i.e. L1=L2=L3=L4, and the differences in the ink levels in adjacent isolated chambers are also equal. In this way, each printing unit is subjected to the same ink pressure, and the ink trajectories of each ejection orifice are also substantially uniform, ensuring the printing quality.

[0031] The printing device proposed in the present application can also be applied to Figure 9 the case shown in Figure 1b, Figure 9 the inkjet printhead and the characteristics of the printing medium shown in Figure 1a are consistent with the above embodiments, and will not be described in detail here. Figure 9 In Figure 1b, the inkjet printhead 1 is arranged along the first direction 45, and the surface to be printed 1 of the printing medium 7 is also arranged along the first direction 45, and the first direction 45 has an angle with the direction of gravity. The normal line K of the surface to be printed is arranged along the direction 48, and the direction 48 has a third angle with the horizontal direction 46, which is 0-90 degrees (the angle is 0 when the surface to be printed is horizontal, and the angle is 90 degrees when the surface to be printed is vertical). Figure 9 The case shown in Figure 1a). The surface to be printed of the printing medium can be a curved surface, such as Figure 9As shown in c, the inkjet print head 1 is arranged along a first direction 45, which is parallel to the direction of gravity, and the surface 71 to be printed of the print medium 7 is curved and faces the inkjet print head 1. A normal of a point 0 on the curved surface of the surface 71 to be printed is along a direction 48, which has a third angle with the horizontal direction 36, and the third angle is 0-90 degrees. Figure 9 d is different from c in that the inkjet print head 1 is arranged along a first direction 45, which has an angle with the direction of gravity, and other features are the same as those of c. Figure 9 c is different from c in that the inkjet print head 1 is arranged along a first direction 45, which has an angle with the direction of gravity, and other features are the same as those of c. Figure 9 c is different from c in that the inkjet print head 1 is arranged along a first direction 45, which has an angle with the direction of gravity, and other features are the same as those of c.

[0032] Correspondingly, the application also proposes a printing method, which uses the printing device of any of the above embodiments, and includes:

[0033] The image processing device transmits the image information to be printed to the printing driving device;

[0034] The motion control device controls the relative motion of the print medium and the inkjet print head along the horizontal direction;

[0035] The printing driving device controls the inkjet print head to spray ink onto the print medium to perform printing.

[0036] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.

[0037] The above embodiments only express several embodiments of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are within the scope of the application. Therefore, the scope of protection of the patent of the application should be subject to the appended claims.

Claims

1. A printing apparatus characterized by comprising: The printing device comprises: an ink cartridge for providing ink; at least one inkjet print head, the inkjet print head comprising at least two print units arranged along a first direction, each print unit being connected to the ink cartridge through a channel; a print medium arranged opposite to the inkjet print head; a print driver for controlling the inkjet print head to print on the print medium; a motion controller for controlling the relative motion between the inkjet print head and the print medium along a horizontal direction; and an image processor for transmitting image information to be printed to the print driver; wherein the first direction has a first angle with the horizontal direction; a normal direction of a surface of the print medium to be printed has a third angle with the horizontal direction; the third angle is 0 degree, and the distance between each print unit and the surface of the print medium to be printed is the same. the first angle is 90 degrees.

2. The printing device according to claim 1, characterized by each print unit comprises at least one column of nozzles arranged along the first direction.

3. The printing device according to claim 1, characterized by, each print unit comprises at least one column of nozzles arranged along a second direction having a second angle with the first direction.

4. The printing device according to claim 1, characterized by, each print unit comprises a plurality of nozzles arranged in a two-dimensional area, and the length direction of the two-dimensional area is parallel to the first direction.

5. The printing device according to claim 1, characterized by each channel is provided with a switch control valve, the first end of the switch control valve is connected to the print unit, the second end of the switch control valve is connected to the ink cartridge, and the liquid pressure at the second end is greater than that at the first end; when the liquid pressure at the first end of the switch control valve is less than a first threshold pressure, the switch control valve is in an open state, and the ink flows from the ink cartridge to the print unit; when the liquid pressure at the first end of the switch control valve is greater than the first threshold pressure, the switch control valve is in a closed state, and the ink stops flowing from the ink cartridge to the print unit.

6. The printing device according to claim 1, wherein The first threshold pressure is lower than the ambient pressure outside the printing device, and the first threshold pressure of the switch control valve provided on each channel is the same.

7. The printing device according to claim 6, wherein The ink cartridge comprises a plurality of isolated chambers, and one channel is connected to one isolated chamber.

8. The printing device according to claim 1, wherein The ink in the plurality of isolated chambers of the ink cartridge is the same.

9. The printing device according to claim 8, characterized by 10. The printing device according to claim 8, further comprising a liquid level control device for controlling the liquid level of the ink in the plurality of isolated chambers of the ink cartridge. The number of the isolated chambers is greater than or equal to the number of the print units.

11. The printing device according to claim 8, characterized by The space above the liquid level of the ink in the plurality of isolated chambers of the ink cartridge is connected to a stable air pressure source.

12. The printing device according to claim 8, characterized by The pressure of the stable air pressure source above the liquid level of the ink in the plurality of isolated chambers of the ink cartridge is the same.

13. The printing device of claim 12, wherein, The liquid level of the ink in the plurality of isolated chambers of the ink cartridge is in a stepped shape.

14. The printing device according to claim 8, characterized by The height difference of the liquid level of the ink between two adjacent isolated chambers is equal.

15. The printing device according to claim 8, characterized by The height difference between two adjacent print units along the direction of gravity is equal to the height difference of the liquid level of the ink in the corresponding two isolated chambers.

16. The printing device according to claim 8, wherein The length of each print unit along the first direction is less than 5 cm.

17. The printing device according to claim 1, wherein The image processor transmits image information to be printed to the print driver; 18. A printing method of the printing apparatus according to any one of claims 1 to 17, characterized by, The motion controller controls the relative motion between the print medium and the inkjet print head along the horizontal direction; The print driver controls the inkjet print head to eject ink onto the print medium for printing. ​ ​

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