JPS6030354A - Inkjet printer - Google Patents

Abstract

PURPOSE:To prevent pressure variations in a common ink chamber in the acceleration and deceleration of the recording head during the reciprocative scanning while improving the scanning speed by forming a bypass path connecting both ends of the common ink chamber. CONSTITUTION:A bypass path 17 is provided to connect two ends of a common ink chamber 16 communicating with a pressure chamber 14 with one end running into a nozzle 19 through a conduction path 18, by way of an ink feed path 15. With such an arrangement, even when the recording head 13 running in the direction of the arrow (b) stops suddenly for change of direction, the flow of an ink in the ink chamber 16 turns in the direction of the arrow (e), causing no changes in the pressure and hence keeps the pressure in balance to almost eliminate the amplitude of the meniscus. In addition, when the head receives an external force, the ink in the ink chamber 16 is fluidized along the length thereof 16 and flows into the bypass path 17 to allow air to be sucked in from both end nozzles 19. Thus, the granulation of the ink can be done continuously without being blocked.

Description

DETAILED DESCRIPTION OF THE INVENTION (&) Technical Field of the Invention The invention particularly relates to an inkjet printer that forms an image by scanning a recording head having a plurality of nozzles back and forth with respect to a recording medium.

(b) Prior Art and Problems In an inkjet printer device, for example, as shown in FIG. reciprocating in the direction of arrow a along a platen (not shown);
A recording head 4 is mounted on the carrier 2. Note that 5 indicates a guide shaft and 6 indicates an ink supply pipe.

FIG. 2 is a sectional view showing details of the recording head 4 of FIG. 1. In the figure, the recording head 4 has a plurality of pressure chambers 7, one of which is communicated with a common ink chamber 9 through an ink supply path 8, and the other is communicated with a nozzle 11 through a conduction path 10. Further, a piezoelectric element (not shown) constitutes a part of the pressure chamber 7, and the pressure in the pressure chamber 7 increases by driving the piezoelectric element.
All ink is ejected from the nozzle 11. In addition, in the common ink supply port 9, there is a re-ink supply port 1 from an ink tank (not shown).
There are 2.

In the case of printing, the recording head 4 reciprocates with respect to the recording medium to form an image, but during the acceleration movement of the reciprocating scan, the ink pressure fluctuation in the common ink chamber causes the difference between the two ends of the recording medium. The meniscus vibration of nozzle 11 was a problem. (The meniscus of the right nozzle becomes convex and the meniscus of the left nozzle becomes concave due to the acceleration at the time of direction change during scanning of the arrow 4 of the illustrated record.) Therefore, in the worst case, air is removed from the nozzle 11. Possibility of discoloration (
(from the left nozzle where the meniscus in the illustrated state is concave), and there is a problem that the ink is not turned into particles.

(e) Purpose of the Invention In view of the above problems, the purpose of the invention is to provide a bypass flow path in the common ink chamber to prevent pressure fluctuations in the common ink chamber during acceleration and deceleration motion during reciprocal scanning of the recording head, and to improve the scanning speed. An object of the present invention is to provide an inkjet printer which is completely improved.(d) An inkjet recording head comprising a pressure chamber configured by the invention, a common ink chamber communicating with the pressure chamber and replenishing ink, and the inkjet recording head comprising: The present invention is an inkjet printer that is completely equipped with a carrier that is mounted and moves in a state facing a recording medium, the common ink chamber being in the same direction as the moving direction of the carrier.

(e) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

Is Fig. 3 an embodiment of the inkjet printer of the present invention?
FIG.

In the figure, 13 is a recording head, 14fd pressure chamber, 15
16 is an ink supply path, 16 is a common ink chamber, 17 is a bypass flow path, 18 is a flow guide path, 19i1 is a nozzle, and 20 is a supply port.

When the inkjet recording head shown in FIG. 2 scans all the directions along the arrows and suddenly stops, the ink inside the common ink chamber 9 moves as indicated by the arrow cicfi, causing meniscus vibrations as shown in d (the nozzles on the right end are convex and the nozzles on the left end are concave). )t nozzle, in the present invention, both ends of the common input chamber 16 are connected to bypass flow path 17'i! i-forming.

By forming the bypass flow path 17 as described above, for example, even if the recording head 13 is scanning in the direction of the arrow e and suddenly stops at the ninth point in the direction change, the ink inside the common ink chamber 16 will flow in the direction of the arrow e. It changes into a flow and maintains an equilibrium state with no pressure change. As a result, the fc meniscus amplitude (about 5 μm in the conventional case) has almost disappeared.0 Also, in the event that the recording head 13 receives an external force, the ink in the common ink chamber 16P3 due to the impact force is Since the ink flows in the direction of the ink and flows into the bypass flow path 17, there is no possibility that the air "vi" will be sucked in from the nozzles 19 at both ends and the ink particles will be turned into gold particles as in the conventional case. It is recommended that the width of the common ink chamber 16 and the width of the flow guide path 17 be set to about 2=1 for the hole indicated by the arrow e in the common ink chamber 16 to improve the flow of ink. In addition, the recording head is usually fabricated by gold etching on a stainless steel substrate, and the bypass flow path 17 of the common ink chamber 16 of the present invention can also be fabricated by etching at the same time, and no special processing steps are required. .

FIG. 4 shows another embodiment of the present invention, in which the present invention is applied to a shuttle type ink jet recording head 25 in which nozzles are arranged over the entire recording width.

In the figure, 21 is a common ink chamber, 22 is a bypass flow path, 23 is a supply port, and 24 is a scanning strip.

Other symbols used in common with those in FIG. Even if the ink inside the common ink chamber 21 suddenly stops due to a change in direction, the ink inside the common ink chamber 21 flows in the direction of the arrow as described above and maintains an equilibrium state without pressure change.

(f) Effects of the Invention According to the invention as explained in detail above, by connecting both ends of the common ink chamber to form a bypass flow path, during the adjustment movement of the reciprocating scan like the conventional recording head, Internal pressure can be made uniform without causing pressure fluctuations within the common ink chamber. As a result, the meniscus amplitude at both end nozzles is eliminated, the reliability of forming ink particles is improved, and the printing speed can be improved without increasing the processing time of the recording head, which is a great effect.

[Brief explanation of the drawing]

Figure 1 is a perspective view illustrating the entire conventional inkjet printer, and Figure 2 shows details of the recording head in Figure 1.
3 is a sectional view showing one embodiment of the inkjet printer of the present invention, and FIG. 4 is a sectional view of the embodiment of the present invention. In the figure, 13.25 is a recording head, 14 is a pressure chamber,
15 is an ink supply path, 16, 21tj: common ink chamber,
17.22 is a bypass flow path, 18 is a conduction path, 19 is a nozzle, 20.23 is a supply port, and 24 is a scanning width.〇7- Figure 1 Figure 2

Claims (1)

[Claims] The inkjet recording head is equipped with a plurality of nozzles, a pressure chamber that communicates with the nozzles and generates pressure in the ink by a pressure means, and a common ink chamber that communicates with the pressure chamber and supplies all the ink, and the inkjet recording head is installed. is,
An inkjet printer completely equipped with a carrier that moves in a state facing a recording medium, characterized by a bypass flow path connecting both ends of the common ink chamber in the same direction as the moving direction of the carrier. inkjet