WO1994029110A1

WO1994029110A1 - Ink jet type recording head

Info

Publication number: WO1994029110A1
Application number: PCT/JP1994/000871
Authority: WO
Inventors: Tomoaki Abe; Kazuo Koshino
Original assignee: Seiko Epson Corporation
Priority date: 1993-06-03
Filing date: 1994-05-31
Publication date: 1994-12-22
Also published as: JP3418986B2; EP0653304A1; EP0653304A4; DE69417347D1; DE69417347T2; EP0653304B1

Abstract

Nozzles (190 to 197) for jetting ink droplets are so disposed along two line segments (L1 and L2) diverging in opposite directions with respect to a main scanning direction. The drop of printing quality and interference in an ink chamber can be solved if the two line segments form a V-shape. Accordingly, the present invention provides an ink jet type recording head capable of high density printing with high printing quality.

Description

Description Inkjet recording head Technical field

The present invention relates to an on-demand ink jet recording head for ejecting ink droplets in response to a print signal to form an ink image on a recording medium such as recording paper, and more particularly to an on-demand ink jet recording head. The present invention relates to an arrangement of nozzles for discharging ink droplets and a shape of an ink chamber. Technology background

In recent years, an ink jet recording apparatus capable of outputting a high-density recording image has been demanded, and an ink jet recording head for realizing a recording density higher than a linear array density of nozzles has been disclosed in Japanese Patent Application Laid-Open No. 60-1985. — It is disclosed in Japanese Patent Publication No. In the ink jet recording head described in this publication, recording heads having nozzles arranged in a straight line are arranged obliquely with respect to the main scanning direction to increase the recording density. However, with this recording head configuration, there is a problem that the printing quality is greatly affected, such as the possibility that the pitch of the recording pixels may be uneven due to dimensional errors such as the mounting dimensions to the carriage. was there.

On the other hand, in the inkjet recording head described in Japanese Patent Application Laid-Open No. Hei 4-3-1259, the nozzles are arranged on a plurality of oblique straight lines as shown in FIG. By arranging them in a zigzag pattern, print quality is improved regardless of the mounting dimensional accuracy.

However, in order to realize high-density recording by the ink jet recording head described in Japanese Patent Application Laid-Open No. Hei 43-12859, the pitch between each nozzle must be adjusted. It must be narrowed, that is, the angle α must be reduced, but the angle is substantially restricted in order to prevent the occurrence of crosstalk and the like due to interference between the ink chambers at the bent part. Was something. In addition, because of the configuration having a plurality of bends, the penetration depth of the ink differs between the recorded image at the bent portion and the recorded image at the peripheral portion, and the recorded image at the entire portion as shown in FIG. A plurality of unevenness was generated.

Therefore, the present invention provides a high-density, high-density printing The purpose is to provide an integrated jet record head. DISCLOSURE OF THE INVENTION The ink jet recording head of the present invention is arranged such that nozzles for ejecting ink droplets are arranged substantially along a V-shaped line opened in the main scanning direction of the recording head. Features. In addition, the nozzles are arranged substantially along the combination line of the diagonal line segment opened in the main scanning direction, and at least one of the nozzles along the adjacent diagonal line segment is oblique. The feature is that the nozzles along are shifted in the main scanning direction.

Further, the nozzle is arranged so as to substantially follow a combination line of the oblique line segment opened in the main scanning direction, and a part of the nozzle along the oblique line segment is shifted in the main scanning direction. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the nozzle arrangement and the ink chamber arrangement of the ink jet recording head of the present invention.

FIG. 2 is a diagram showing a printing state of the first embodiment of the present invention.

FIG. 3 is an enlarged view of a part of the nozzle according to the first embodiment of the present invention.

FIG. 4 is a graph showing a pixel displacement according to the first embodiment of the present invention.

FIG. 5 is a perspective view for explaining a mounting state of the ink jet recording head of the present invention.

FIG. 6 is a perspective view showing a transport mechanism of the ink jet recording head of the present invention.

FIG. 7 is a diagram showing a print pattern according to the first embodiment of the present invention.

FIG. 8 is a view showing an ink jet recording head according to another embodiment of the present invention. FIG. 9 is a view showing an ink jet recording head according to another embodiment of the present invention. FIG. 10 is a view showing an ink jet recording head according to another embodiment of the present invention. FIG. 11 is a diagram for explaining the ink jet recording head of the present invention. FIG. 12 is a diagram for explaining a conventional nozzle arrangement and an ink chamber arrangement.

FIG. 13 is a diagram illustrating a printing state according to the related art. BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory diagram of the nozzle and ink chamber arrangement of an ink jet recording head according to one embodiment of the present invention. In FIG. 1, the recording head of this embodiment includes nozzles 190 to 197 for ejecting ink droplets, and ink chambers 170 to 177 communicating with the nozzles. . Although partially omitted in this drawing, each room has an ink chamber that communicates with a total of 64 nozzles in a row. In the figure, the nozzles are spaced at regular intervals along lines L1 and L2, which are straight lines inclined in the direction opposite to the X direction, which is the main scanning direction (moving direction when the carriage is mounted). Are located. This line segment is inclined so that the pitch P1 of each nozzle in the sub-scanning direction becomes 1360 inch << ¾, and line segment L1 and line segment L2 are almost V-shaped. It is formed in a shape.

The ink chambers are arranged outside the V-shape formed by the line segments L 1 and L 2, and the width d 4 of each ink chamber is 450 μm, which is sufficient. It is formed wide enough to obtain the discharge rate and 150 m deep to ensure ink flow characteristics.

As a pressurizing means for pressurizing the ink chamber configured as described above, a piezoelectric element is attached to a vibration plate that forms a wall of the ink chamber, or a piezoelectric element is printed on a gripping plate. A product formed by firing can be used.

The overall dimensions of the nozzle of this example were w = d1X24 = 13.55 mm, h = 1x47 = 3.32 mm.

According to the recording head of the present invention, the nozzles are arranged in a V-shape, so that the recording head described in Japanese Patent Application Laid-Open No. HEI 4-3125859 has a light and shade. As shown in Fig. 2, the problem of multiple unevenness was reduced to a point where the print density was high only at the center of the nozzle 192 near the center, and the density was uniform near the nozzle 199 at the end. Transform This makes it possible to suppress density unevenness to a minimum at one location over the entire printing width b. As a result, even when a bite image such as graphics is recorded by using the recording head of the present embodiment, high quality output is possible without deteriorating the texture.

In the present embodiment, as shown in FIG. 1, among the nozzles along the oblique line segments L1 and L2 adjacent to each other, the nozzles along the oblique line segment L2 (nozzle 191 in the figure) , 19 5, 1 96, 19 7) in the main scanning direction (one X direction in the figure) with respect to the position of the nozzle 19 2, d 2 = dlx 2.5 = ρ 1 Χ 20 Displaced, and further arranged so that the distance p2 in the sub-scanning direction between nozzles 192 and 191, which are the ends of line segments L1 and L2, is the same pitch as p1 did. Further, the pitch between the nozzle 1994 and the nozzle 1991 was arranged so as to be p1X3. FIG. 3 shows a partially enlarged view of the bent portion where the nozzle is shifted. In this embodiment, as shown in the figure, the nozzle row along the line segment L2 is shifted by 2.5 nozzles in one X direction from the nozzle row along the line segment L1, so that the line segment L1 A nozzle 191 along L2 is arranged at a position of dl / 2 between the nozzle 193 and the nozzle 194. In this way, by displacing the shift amount d 2 = dlx 2.5 = plx 20, the shortest distance between the closest nozzles 191 and 194 can be maintained while ensuring sufficient printing density. The large size makes it possible to obtain sufficient rigidity of the wall between the ink chambers 17 1 and 17 4, and to eliminate adverse effects on ink discharge such as crosstalk. .

The shift amount d2 is set to d2 = dlx2.5 = plx20 and an integer multiple of the print pitch pi, and the nozzles shifted in the main scanning direction (nozzles 191, 195, 1 in the figure) 9, 1 9 7) is a basic timing in the main scanning direction (in this embodiment, the basic timing interval is equivalent to the pitch P 1). 1 is counted as 20 for nozzle 192) so that it can be obtained accurately. The basic timing in the main scanning direction can be obtained directly from the linear encoder output arranged in the same direction or the pulse number of the stepping motor for driving the recording head. In this embodiment, with such a configuration, high printing quality is achieved by accurately forming pixels even from nozzle groups shifted in the main scanning direction without adding a special timing generation mechanism. did. Further, in the present embodiment, the shape of the ink chamber near the nozzle is not formed by a simple curved surface of R, but the vicinity of the nozzle is formed by a smaller curved surface of R. The distance can be made wider, interference such as crosstalk can be more reliably eliminated, and bubbles can be discharged by gradually decreasing the radius of the curved surface near the nozzle. It also has an excellent effect on properties.

In the present embodiment, the shortest distance d 5 = 3 5 2.8 m is the distance r 1 = 100 〃 m from the center of the nozzle 19 1 to the outer shape of the ink chamber 17 1 and the nozzle 19 4 The distance from the center to the outer shape of the ink chamber 1 74 r 1 = 1 0 O The sum of m, which is greater than d 6 = r 1 + r 2 = 200 jm, and r 3 is greater than 100 zm It can be widened, and the rigidity of the wall between the ink rooms is kept very high.

The recording head according to the present invention is unlikely to cause a decrease in printing quality due to an attachment error or the like. This will be described in detail below.

Since the printing pitch P 1 in the present embodiment is 1/360 inch-70. 6> um, taking into account that the recording medium is completely covered, The diameter of the pixel is desirably about 100 to 12 Ozm. With this pixel size, the displacement of the 20 to 30 ju pixel is visually perceived, and causes a reduction in print quality. In this embodiment, the displacement of the nozzle 195 due to the angle 0 is as follows: x = h X7T X 0/180 in the X direction, A y = d 3 X 7T X 0 Zl 8 O in the y direction. (H = plx 47 = 3.32 mm, d 3 = d 1 X 2.5 = 1.41 mm), and the actual displacement is shown in Fig. 4 for the angle 0. become. Generally, the angle 0 is about 0.1 degrees including the backlash and component accuracy, and the misalignment is as small as 6 m and Ay = 2.5 m, and is applied with sufficient print quality. It is possible to do so.

The recording head of the present invention has a problem in mounting accuracy to a carriage in an ink jet recording apparatus configured so that the user can easily replace the recording head for the above-described reason. It can be easily implemented without any problems.

Such a recording device can be easily mounted even if it is a recording device composed of a simple support mechanism such as an arm 360 and a pin 361, as shown in FIG. This recording apparatus moves the recording head 9 in the main scanning direction (X direction in the figure) relative to the recording medium while ejecting ink droplets 50 from the nozzle 190 and the like. Recording media 1 Form a pixel on top. After the pixel formation in the main scanning direction is completed in this way, the recording medium 1 is transported in the sub-scanning direction (the y direction in the figure) perpendicular to the main scanning direction, and then the main scanning direction ( Recording proceeds in the process of forming pixels in the (X direction in the figure). The conveyance of the recording head is performed by driving the belt 6 via the pulley 5 by the steering motor 10 as shown in FIG. Even if an error occurs in the feed amount in the main scanning direction due to the eccentricity of the pulley 1-5, the vibration of the belt 6, or the expansion and contraction due to the external environment, printing using the recording head of this embodiment is shown in FIG. Since the pattern is smooth and continuous, there is an advantage that high-quality printing can be provided without visually conspicuous disturbance such as vertical lines.

FIG. 8 shows another embodiment of the present invention. The present embodiment is characterized in that a part of the nozzle (nozzle 192 in the figure) along the oblique line segment L 1 is shifted in the main scanning direction (X direction in the figure). In this way, the nozzle 1992 is shifted earlier than the nozzle 1992 by shifting it larger than the nozzle 191 that discharges the next ink (d7 = dlx3). Pixels are formed early by discharging and drying ink droplets on the recording medium, and the next ink droplet from nozzle 191 is formed by the ink droplet from nozzle 192. Even if it overlaps, the image formed by the nozzles 192 is dry, so that partial collection of ink droplets can be prevented and density unevenness at the center of printing can be further suppressed. . In the present embodiment, only the nozzles 19 2 are shifted, but if a plurality of nozzles are shifted, the effect of density unevenness is further increased.

FIG. 9 shows another embodiment of the present invention. In this embodiment, the nozzle array is configured so as to be along a plurality of line segments LI, L2, L3, and L4. For example, black is assigned to L1, cyan is assigned to L2, and cyan is assigned to L3. Magenta and L4 are assigned different colors like yellow. Separate L1 and L2, L3 and L4 in the main scanning direction (x direction), and separate nozzles 190 and 91 and nozzles 1992 and 1993. As a result, the ink of another color flows into the nozzles 190, 191, 192, 193 to prevent color mixing and smearing. FIG. 10 shows another embodiment of the present invention. This recording head is formed in a diamond shape by combining two V-shaped nozzle arrangements. According to this nozzle arrangement, when printing in the main scanning direction, one V-shaped nozzle performs thinned-out printing, and then records with another V-shaped nozzle so as to fill the gap. Problems such as ink bleeding Can be resolved.

The structure of the ink jet recording head for realizing the above-described ink jet recording head of the present invention is a stacked ink jet head as shown in FIG. A ceremony record head is preferably used. According to this recording head, the flow path from the ink chamber 17 to the nozzle 2 can be easily shifted gradually from the flow path in which the nozzles 2 are stacked. Since the position can be shifted to the outside of the ink chamber from the end of the ink chamber 17, the position of the ink chamber can be lower than the position of the nozzle. When such a configuration is employed in a nozzle arrangement having a bent portion as in the embodiment of the present invention, the distance between adjacent ink chambers can be more sufficiently increased, and crosstalk can be reduced. Not only can this be sufficiently prevented, but also the distance between the nozzles can be reduced, and high-density placement of the nozzles becomes possible. In FIG. 11, ink is supplied from a common ink chamber 11 to an ink chamber 17, and a diaphragm 19 laminated on the ink chamber 17 is pressurized by a piezoelectric element 20. Thus, the nozzle 2 is configured to be discharged from the nozzle 2 through the flow path.

As described above, according to the present invention, recording can be performed at a high recording density, printing unevenness is suppressed, and recording quality is not affected by mounting errors, and highly integrated ink jet recording is performed. Can be provided. Industrial applicability

As described above, the ink jet recording head of the present invention is suitable for use in a recording device such as a printer, a facsimile, and a copying machine.

Claims

The scope of the claims

1. An ink jet recording head having a plurality of nozzles for discharging ink droplets,

The plurality of nozzles are arranged at intervals on a straight line inclined in a direction opposite to a main scanning direction which is a moving direction of the recording head, and the nozzle row is formed in a substantially V shape. An ink jet recording head characterized in that:

2. The ink jet according to claim 1, wherein at least one nozzle row on a straight line inclined is displaced in the main scanning direction with respect to the other nozzle row. G record head.

3. The ink jet printer according to claim 2, wherein the shift amount in the main scanning direction is shifted so that the nozzles of one nozzle row are arranged between the nozzles of the other nozzle row. Head-type record head.

4. The inkjet recording head according to claim 2, wherein the shift amount in the main scanning direction is at least 2.5 times the nozzle interval.

5. The ink jet according to any one of claims 1 to 4, wherein a nozzle is provided at a position spaced apart from an end of the inclined nozzle row on the bent portion side. Head of ceremony record.

6. The ink chamber communicated with the nozzle is formed by a multi-step curved surface having a smaller radius near the nozzle. Ink jet recording head described in item 5.

7. The ink jet recording head according to claim 1, wherein the nozzle rows are arranged in a diamond shape.

8. The ink jet recording head according to claim 1, wherein the ink jet recording head is a laminated type in which an ink chamber and a nozzle position are variable. Heh H o