JPS61141562A - Bubble trap integral-type ink cartridge - Google Patents

Abstract

PURPOSE:To attenuate pressure variations generated in an ink bag and prevent the pressure variations from being transmitted to a head part, by a construction wherein an ink bag of an ink cartridge is composed of a bellows form part formed of a flexible plastic film and a rigid part for trapping bubbles, and partition plates are provided in the ink bag. CONSTITUTION:The ink bag 7 formed of a flexible plastic film or a rubber material is formed in a belows shape, in which the partition plates 8 for partitioning the interior thereof into small parts are provided, and the bubble trap part 13 connected to the bellows part is formed in a ridged form from a rigid or thick plastic film or a thick rubber. When the ink bag is contracted concurrently with the consumption of an ink, the ridge parts of the bellows are collapsed into an acute-angled shape, so that the bubbles trapped therein are successively collected into the ridged part of the rigid film. Though pressure variations are generated when the bellows is contracted in the axial direction, the partition plates 8 attenuate the pressure variations, and prevent the pressure variations from being transmitted toward a head.

Description

[Detailed description of the invention] Thorn 4 minutes! The present invention relates to a bubble trap in an ink cartridge integrated head of an on-demand inkjet recording device that can be applied to facsimiles, color plotters, and the like.

In an inkjet recording device that ejects an ink stream from an inkjet head and prints granular ink droplets on recording paper, ink is supplied under pressure to the pressure chamber of the head, and the electrostrictive vibrator The strain is used to temporarily increase the pressure in the pressure chamber and ink is ejected from the nozzle. However, if air bubbles enter the pressure chamber, even if an attempt is made to increase the pressure within the pressure chamber by driving the electrostrictive vibrator, the pressure will be absorbed by the air bubbles and a sufficient pressure increase will not be obtained.

Ink may not be ejected from the nozzle. In order to avoid such a situation, various proposals have been made in the past. For example, there is a device that uses the upper part of the common liquid chamber of the head as an air bubble trap and floats air bubbles mixed into the head there (Japanese Patent Laid-Open No. 52-490
However, the small bubbles sent to the common liquid chamber may be mixed into the flow path toward the nozzle during floating.

The capacity is insufficient to trap the large amount of air bubbles generated in the ink bag inside the ink cartridge.

There is also a device that has a bubble detection section in the middle of the ink flow path leading to the head (Japanese Patent Laid-Open No. 55-166651).
It is not clear what to do after detection, and some ink bags contain a second bag containing a deaerator (Japanese Unexamined Patent Publication No. 177446/1982), but it is not possible to use the ink effectively. The amount decreases, and the material of the second bag becomes a problem in terms of wettability. Furthermore, in addition to the head and ink cartridge, an air bubble trap is provided in the middle of the supply path of the head and ink cartridge.
No. 58), but this increases the number of component parts and cannot prevent the air bubbles that have passed through the tube between the air bubble trap and the head from being sent toward the head.

Next, a head-integrated ink cartridge for an on-demand inkjet recording apparatus will be described.

FIG. 4 shows a conventional head-integrated ink cartridge, in which 20 is a head section, 21 is an ink cartridge, and 22 is a head-integrated ink cartridge.
is an ink bag, and the ink bag 22 has a function of reducing ink consumption.
It is made of a soft plastic film or rubber film to prevent the generation of negative pressure by shrinking, and to prevent ink supply shortages or ink supply failures. 23 is the ink outlet tube.

The ink introduction part at the tip is cut diagonally upward,
Even if the floating air bubbles E float slightly curved toward the ink introduction section due to the outflow velocity accompanying ink consumption, there is little fear that they will be taken into the ink outlet pipe and will be prevented from being led out to the head section. ing.

As shown in the figure, the ink outlet tube 23 has a long protrusion in the center, which maintains the shape of the ink bag as the ink is consumed and prevents the ink bag from collapsing locally and ink from not being used effectively. ing. That is, as shown in FIG. 5, if there is no ink outlet tube and only the ink outlet hole 24, the ink bag 22 is soft and the way the film collapses is uncertain, so the ink bag will not come into close contact with the P section. , a large amount of ink in part B may be blocked and become unusable, or trapped air bubbles accumulated in part A may be trapped in the ink outlet hole 24.
There is a possibility that the liquid may flow into the head section through the hole. For this purpose, an ink outlet pipe 23 is provided, and a sixth
As shown in the figure, there are grooves 2 on the outer wall of the ink outlet tube 23.
5 (see the cross-sectional view in Figure (B)), the ink bag 22
Even if a portion of the block portion A is in close contact with the outlet tube 23 at the P1+ portion 22 and the block portion A remains, the ink in the B portion is led out through the groove 25.

However, in the head-integrated ink cartridge as described above, the film of the ink bag is thin enough to be shrinkable, so air can pass through it and bubbles cannot be formed if the solubility of the ink is exceeded. In this respect, the conventional method was insufficient in trapping air bubbles.

Part of the present invention has been made in view of the above circumstances, and provides a head-integrated ink cartridge for an inkjet recording device, which has a simple structure, is inexpensive, can effectively trap air bubbles, and is capable of trapping air bubbles within the ink bag. It is an object of the present invention to provide an ink cartridge that can effectively attenuate pressure fluctuations that occur.

In order to achieve the above object, the present invention provides an on-demand inkjet recording device in which a head unit and an ink cartridge are integrated, in which the ink bag of the ink cartridge is a bellows-shaped portion made of a light plastic film. , and a hard material part connected to the bellows-shaped part to trap air bubbles. below,
An explanation will be given based on an example of the present invention.

FIG. 1 is a diagram showing an embodiment of a head-integrated ink cartridge according to the present invention, in which 1 is a head body, 2 is a nozzle, 3 is a pressurized liquid chamber, and 4 is a vibrator.

A diaphragm, 5 is a liquid path, 6 is an ink outlet tube, and the introduction part is cut diagonally upward. Reference numeral 7 denotes an ink bag made of a soft plastic film or rubber material, and the ink bag 7 is formed into a bellows shape, traps air bubbles floating to the triangular part of the bellows, and traps air bubbles that float up as the ink is consumed. Shrinks in the axial direction. Reference numeral 8 denotes a partition plate that divides the inside of the ink bag into small pieces. Air bubbles E generated inside the bag or transmitted from the outside through the film are attached to the partition plate 8 and made to float, so that the air bubbles are not sent to the head unit through the ink outlet pipe. A gap G is provided between the bellows and the bellows. Furthermore, a communication hole 9 is provided below the partition plate 8, so that ink can easily flow toward the outlet tube 9. 10 is a fixed case, 11 is a cartridge housing, 12 is a breathing hole,
Reference numeral 13 denotes a bubble trap section connected to the bellows part of a soft plastic film, which is formed into a chevron shape of hard or thick plastic or thick rubber, and hardly contracts under the negative pressure generated by ink consumption, and does not trap air bubbles. 14 is ensured, and the amount of permeation and intrusion of external air is extremely small compared to the thin walled portion of the bellows.

As shown in Figure 2, when the ink bag shrinks as the ink is consumed, the air bubble trap collapses into an acute angle, so the air bubbles trapped in the bellows collapse into a stiff film. It accumulates in the area. When the bellows contracts in the axial direction, pressure fluctuations occur, and the partition plate 8 also serves to attenuate the pressure fluctuations so that they are not transmitted to the head.

FIG. 3 shows another embodiment of the present invention, in which the bubble trap section is made of a rigid body (thick-walled plastic) and only one partition plate is used.

In both the cases of Figures 1 and 3, the ink capacity in the thick bubble trap remains unconsumed, but compared to the conventional ink bag constructed of only a thin film as shown in Figure 4. The remaining amount is fixed compared to the conventional ink cartridge, and there is no risk of air bubbles getting into the ink outlet tube that supplies ink to the head.

Note that this embodiment deals with the trapping of air bubbles in the ink bag, and the air bubbles generated in the flow path from the air bubble trap section to the nozzle in this embodiment are treated by using a thick-walled (resin) material for forming the head flow path. It is better to take auxiliary measures to trap small amounts, such as by attaching and molding mold flow path plates, or by placing the common liquid chamber above the nozzle.

As is clear from the above description, according to the present invention, in a head-integrated ink cartridge, it is possible to trap a large amount of air bubbles, including micro-bubbles, generated within the ink bag, and also to trap a large amount of air bubbles, including micro air bubbles, generated within the ink bag. Since the plate is provided, pressure fluctuations generated within the ink bag can be attenuated and prevented from being transmitted to the head section.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of a head-integrated ink cartridge according to the present invention, FIG. 2 is a diagram showing a bubble trap, and FIG. 3 is a diagram showing another embodiment according to the present invention. Fig. 4 shows a conventional head-integrated ink cartridge, Fig. 5 shows a deflated state of an ink bag without a conventional ink outlet tube, and Fig. 6 shows a deflated state of a conventional ink bag. FIG. DESCRIPTION OF SYMBOLS 1... Head body, 2... Nozzle, 3... Pressurized liquid chamber, 4... Vibrator, 5... Liquid path, 6... Ink outlet pipe, 7... Ink unit Main body, 8... Partition plate, 9...
・Communication hole, 10... Fixed case, 11... Cartridge housing, 12... Breathing hole, 13... Air bubble trap part, 14... Air bubble, E... Air bubble, G... Gap . Patent applicant Ricoh Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 1iE4 Figure 5

Claims (4)

[Claims] (1) In an on-demand inkjet recording device in which a head unit and an ink cartridge are integrated, the ink bag of the ink cartridge is connected to a bellows-shaped portion made of a soft plastic film and the bellows-shaped portion to trap air bubbles. An ink cartridge with an integrated air bubble trap, characterized by comprising a hard material part. (2) The bubble trap integrated ink cartridge according to claim (1), characterized in that one or more partition plates are provided within the ink bag. (3) The ink cartridge integrated with a bubble trap as set forth in claim (2), characterized in that a communication hole is provided in the lower part of the partition plate. (4) According to any one of claims (1) to (3), the hard material portion that traps air bubbles has a raised mountain-shaped portion. Ink cartridge with integrated bubble trap as described.