JPH04156332A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To adjust characteristics of each ink flow passage and enable data to be correctly recorded at a high printing grade by arranging pressure chambers in circular arc, and locating the pressure chambers in respective positions corrected in the radial direction of the circular arc so that the length of each ink flow passage between a nozzle and the pressure chamber becomes equal, respectively. CONSTITUTION:Pressure chambers are to be arranged so that the size of each of their ink flow passages from a nozzle 1 to a nozzle side flow passage 5 becomes equal in width, length and depth. As compared with a pressure chamber A, however, a pressure chamber D has the length of its flow passage from the nozzle to the pressure chamber, that is shortened by DELTAr because the pressure chambers A to D are arranged on a circular arc at a given angle theta for each of their flow passages. Therefore, the respective pressure chambers A to D are shifted in the radial direction of the circular arc with the point 0 as a center by the length DELTAr that is shortened in respective flow passages so as to be located in A and B' to D' positions, respectively. For example, since the length of the flow passage from the nozzle to the pressure chamber D is shortened by DELTAr=D1-D1D2 in the D flow passage, the position of the pressure chamber D is shifted to the position D' corrected by DELTAr toward the outside of the radial direction of the circular arc with the point 0 as a center, and the pressure chamber D is set in this position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording device, and more particularly to an ink flow path of an inkjet recording device.

[Conventional technology]

Conventionally, in order to equalize the flight characteristics of ink droplets, JP-A-58-7363 sets the acoustic resistance and inertance to be approximately equal for each nozzle or ink supply path, and JP-A-59-159,356 sets almost the same acoustic resistance and inertance for each nozzle or ink supply path. The width and length are almost equal. In these inkjet recording devices, the shape and length of the ink flow paths are different for each flow path, and the arrangement of pressure chambers and piezoelectric elements is also different for each flow path.

[Problem to be solved by the invention]

However, in these conventional examples, when designing an ink flow path, a large number of calculations are required to align the acoustic resistance and inertance for each flow path, and in the case of flow paths with greatly different shapes, Because it took a lot of time to draw the diagrams, it took a huge amount of time to design and ship.

Further, since the shape of each flow path is greatly different, it is inevitable that variations in characteristics will occur between the nozzles. In an inkjet recording apparatus, if there are differences in the characteristics of each ink flow path, differences appear in the ink weight, ink speed, and time for ink droplets to reach the paper surface. When the weight of the ink changes, the diameter of the dots constituting a pixel is no longer constant, resulting in density differences in the print results, making it impossible to print with good quality. Further, since the alignment of the dots is disturbed due to the difference in ink speed between each flow path, information cannot be recorded accurately in this case as well. In addition, if there is a difference in the arrival time of the main and satellite ink droplets that make up one dot, the shape and size of the dots will vary and become non-uniform, making it difficult to print when outputting a figure. The thickness of the printed lines also becomes uneven, making it impossible to print beautifully and with high quality.

Furthermore, in the manufacturing process, because each flow path has a different shape, management and inspection become complicated, leading to an increase in the number of manufacturing steps, and it is inevitable that the head will be difficult to manufacture. .

In any case, the conventional technology has had the problem that it is extremely difficult to easily design and manufacture the same characteristics for each flow path and realize a high-quality inkjet recording device.

The present invention is intended to solve these problems, and its purpose is to make it possible to accurately record information with high print quality by aligning the characteristics of each ink flow path, and to improve its design and design. An object of the present invention is to provide an inkjet recording device that is easy to manufacture.

[Means to solve the problem]

In order to solve the above-mentioned problems, an inkjet recording device according to the present invention prints information by ejecting ink droplets as a unit of pixels. and a plurality of piezoelectric elements arranged on the pressure chambers of the substrate, the pressure chambers are arranged in an arc shape, and the pressure chambers are located between the nozzle and the pressure chambers. The ink channels are arranged with their positions corrected in the radial direction so that the lengths of the ink channels are equal to each other.

[Effect]

With the above configuration of the present invention, the shape of each flow path is made the same, which facilitates the design, and since there is no difference in the characteristics of each flow path, the flight characteristics of ink droplets of each flow path are the same, resulting in improved printing quality. It will be possible to improve and stabilize it. Furthermore, since there is little difference in shape between channels, management and inspection procedures can be simplified during the manufacturing stage, and manufacturing costs can also be reduced.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. The same numbers refer to the same parts in all drawings.

FIG. 1 shows an embodiment of an on-demand type inkjet recording apparatus using piezoelectric elements. FIG. 1 is a plan view of a channel substrate of an inkjet recording apparatus according to the present invention.

FIG. 2 is a sectional view of the inkjet recording apparatus of the present invention. The first substrate 20 is made of plastic such as polycarbonate, polyethersulfone, polyimide, glass, or photosensitive resin such as ultraviolet curing resin, and the common ink chamber JO, pressure chamber 2, nozzle 1, etc. are formed by injection molding or etching. It is formed by processing, laser scribing processing, or ultraviolet irradiation processing. 1 is the board 20
2 is a pressure chamber, 3 is a piezoelectric element, 4 is an ink supply port, 5 is a nozzle side flow path, 6 is a supply side flow path, 7
21 is a metal plate or a conductive vapor deposition surface, and 21 is a second substrate made of the same material as the first substrate. Reference numeral 30 denotes a supply pipe through which ink is supplied from a separately provided external ink holding section. The second substrate 21 is welded to the first substrate 20. Nozzle 1 sandwiched between the second substrate and the first substrate
The inside of the ink flow path from the supply pipe 30 to the supply pipe 30 is filled with ink supplied from the supply pipe 30. The piezoelectric element 3 has a size comparable to that of the pressure chamber 2, and is bonded onto the second substrate 21 via a metal plate or a conductive vapor deposition surface 7 in alignment with the pressure chamber 2. The piezoelectric element 3 has the property of contracting when voltage is applied. Utilizing this property, a voltage is applied to the piezoelectric element 3 to cause it to contract, thereby bending the second substrate 21 via the metal plate or conductive vapor deposition surface 7. At this time, the pressure chamber 2 eliminates ink having a volume corresponding to the deflection of the second substrate 21. This removed ink is ejected from the nozzle-side flow path 5 through the nozzle 1 in the form of ink droplets. Also,
When the voltage applied to the piezoelectric element 3 is removed, the volume of the pressure chamber 2 returns to its original volume. At this time, the pressure chamber 2 is filled with the returned volume of ink from the supply pipe 30 through the common ink chamber 10, the supply port 4, and the supply side channel 6, and the pressure chamber 2 is filled again. By repeatedly applying voltage to the piezoelectric element 3, the ink droplets become pixels and information can be recorded.

If there are differences in the characteristics of each ink flow path in an inkjet recording device, differences will appear in the ink weight and ink speed. If the weight of the ink changes, the diameter of the dots making up the pixels will no longer be constant, making it impossible to accurately record information. Further, since the alignment of the dots is disturbed due to the difference in ink speed between each flow path, information cannot be recorded accurately in this case as well. In the present invention, information can be recorded accurately by matching the characteristics of each ink flow path.

The pressure chambers 2 or piezoelectric elements 3 are arranged so that the width, length, and depth of each ink flow path from the nozzle 1 to the nozzle side flow path 5 are equal. In order to simplify and rationalize the design for obtaining these ink flow paths,
The size values for each channel may be made equal. That is, as shown in FIG. 3, the pressure chambers A to D may be arranged on an arc of radius r centered on an arbitrary point O with a constant angular pitch θ.

With this configuration, it is possible to design a space-saving head while preventing mutual interference of vibrations and pressures that occur during driving between the nozzles. However, since the nozzle parts must have a certain distance p and be parallel, the pressure chamber A
-D are arranged on a circular arc with a constant angular pitch θ, the lengths from the nozzle to the pressure chambers AD for each channel will not be strictly equal. On the other hand, in conventional examples, either the shape from the nozzle to the pressure chamber is changed for each flow path to equalize the inertance or acoustic resistance that determines the flight characteristics of ink droplets, or I had to either ignore the difference in .

What is important here is that pressure chamber A is compared with pressure chamber A.
Pressure chambers A-D are arranged on a circular arc at a constant angular pitch θ for each flow path.
This means that the length of the flow path between the nozzle and the pressure chamber is shortened by Δr due to the arrangement. In the present invention, as shown in FIG. 3 of the embodiment, each pressure chamber A-D is moved in the radial direction of an arc centered on point O by the length Δr that is insufficient in each flow path. , A and B~D'. For example, in the flow path D, the length of the flow path from the nozzle to the pressure chamber is shorter by Δr=OD1-DID2, so the radius of the arc centered on point ○ is 61 minutes shorter than the pressure chamber position. It was moved outward in the direction to the corrected position D'', and a pressure chamber was provided at this position.

As a result, the lengths from the nozzles to the pressure chambers of each flow path are all strictly equal, and when designing an inkjet recording apparatus, it is only necessary to calculate the acoustic resistance and inertance for one flow path. Therefore, the procedure can be greatly simplified and the time required for design can be shortened. Furthermore, since the basic dimensions such as length, width, and depth for each channel are the same, the flight characteristics of ink droplets are the same for each channel, making it easy to perform high-quality and stable printing. Similarly, since the flow path shapes for each flow path do not differ greatly, management and inspection can be facilitated at the manufacturing stage, and manufacturing costs can be reduced.

The series of effects described above through an embodiment of the present invention, in which the flight characteristics of ink droplets in an inkjet recording device can be made uniform by aligning the pressure chambers, and the design becomes very easy, is an embodiment of the present invention. It is not something that can only be captured by.

〔Effect of the invention〕

As described above, the inkjet recording device of the present invention has
When designing an inkjet recording device, it is only necessary to calculate the acoustic resistance and inertance for one Ω flow path, which greatly simplifies the procedure and reduces the time required for design. In addition, since the basic dimensions such as length, width, and depth for each flow path are the same, the flight characteristics of ink droplets are the same for each flow path, and the ink weight, ink speed, and arrival time of ink droplets to the paper surface are the same. Because they are aligned, there is no density unevenness in the print result, and the printing alignment is uniform, making it possible to print beautifully, with good quality, and with stability. Similarly, since the flow path shapes for each flow path do not differ greatly, management and inspection can be facilitated at the manufacturing stage, and manufacturing can be easily performed with fewer steps, which has great effects.

[Brief explanation of drawings]

FIG. 1 is a plan view of an ink flow path portion of an inkjet recording apparatus that is an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an ink flow path portion of an inkjet recording apparatus according to an embodiment of the present invention from the side. FIG. 3 is a conceptual diagram of a flow path layout showing the arrangement of pressure chambers or piezoelectric elements of an inkjet recording apparatus according to an embodiment of the present invention. 1... Nozzle 2... Pressure chamber 3... Piezoelectric element 4... Supply port 5... Nozzle side channel 6... Supply side channel 7... Metal plate or conductive vapor deposition surface 10...
Common ink chamber 20...First board 21...Second board 30...Supply pipe and above Applicant Seiko Epson Corporation Representative Patent Attorney Kizobe Suzuki and others

Claims (1)

[Claims] An inkjet recording device that prints information by ejecting ink droplets as units of pixels includes a substrate having a plurality of nozzles, a plurality of ink flow paths, and a plurality of pressure chambers, and a substrate disposed on the pressure chambers of the substrate. The pressure chambers are arranged in an arc shape, and the pressure chambers are positioned in the radial direction so that the lengths of the ink flow paths between the nozzle and the pressure chamber are equal to each other. An inkjet recording device characterized in that the inkjet recording device is arranged in a corrected manner.