JPH0521750B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a residual ink detection device, and more particularly to a residual ink detection device for detecting residual ink in an ink storage container used in an inkjet printer.

BACKGROUND ART Conventionally, inkjet printers record information such as characters and pictures as dots by colliding liquid ink with the paper in the form of droplets according to the information to be recorded.

Therefore, ink must be stored as a liquid, like gasoline in a car.Furthermore, when the ink is ejected, the ink scatters and contaminates the surrounding area, so the ink must be stored to prevent it from leaking due to vibrations or shocks. Must be stored in a container. Furthermore, since the ink must be stored so that its physical properties, such as surface tension, viscosity, and pH, are constant, it is necessary to prevent evaporation and deterioration of the ink components as much as possible. In addition, in the case of an ink jet printer, the ink is ejected by applying a voltage only when recording is necessary, instead of ejecting the ink by pressurizing it and selectively charging and deflecting the droplets to record. It is necessary to keep the ink level constant and at the same pressure as the atmosphere.

On the other hand, when the amount of ink remaining in the ink container becomes low, it becomes necessary to replenish the ink or replace the ink container.

As an ink storage container that satisfies these conditions, a structure as shown in FIGS. 1 and 2 is used. That is, in FIG. 1, ink 2 is stored in a storage bag 1 having a three-layer structure, and the entire ink storage bag 1 is stored in an ink cassette 4 provided with a ventilation hole 3. The structure is such that the ink 2 is led out to the outside through the arranged lead-out pipe 5 and rubber stopper 6. Specifically, the ink 2 is taken out by connecting the hollow needle 7 to the outlet pipe 5 led to the rubber stopper 6. For example, as shown in FIG. 2, this ink storage bag 1 has a nylon outer protective plastic thin film 8 with a thickness of 5 to 10 μm, and an aluminum thin film 9 with a thickness of about 10 μm to prevent ink evaporation and deterioration due to ultraviolet rays. and an inner main bag 10 made of a polyethylene thin film with a thickness of 50 to 70 μm.

In the case of an ink storage container constructed in this manner, ink is replenished by replacing the entire case or cassette, and the old cassette is discarded. The ink storage bag 1 is a flat bag, and the ink level changes by a maximum of about 10 mm from when it is full to when it is empty, and is configured to minimize changes in pressure.

When connecting an ink storage container configured in this way to an inkjet printer for recording,
It is known that when the remaining amount of ink becomes low, printing suddenly becomes impossible without the print density gradually becoming lighter. Such a printing failure phenomenon also occurs when an impact is applied to the device, and it is impossible to determine whether the printing failure is due to the impact or the printing failure is due to a low amount of ink remaining. Therefore, it is necessary to accurately inform the user of the remaining amount of ink in order to replenish the ink, replace the ink storage bag, or determine whether printing is impossible due to impact.

Conventionally, a mechanism as shown in FIG. 3 has been generally used to detect the amount of liquid remaining in a liquid storage container. That is, in the mechanism shown in FIG. 3a, a float 12 with a built-in magnet is suspended in a side channel 13 of a liquid container 11, and a reed switch 14 is disposed opposite the side channel 13.

When the liquid 15 in the liquid container 11 becomes low, the float 12 in the side passage 13 is lowered according to the level of the liquid 15, and the reed switch 14 is operated to detect the remaining amount of ink. Also, Figure 3b
The mechanism shown in Figure 1 detects the remaining amount of liquid by using a light emitting means 16 and a light receiving means 17 instead of the reed switch 14. When the amount of liquid such as opaque ink decreases to below a predetermined level, light is detected. This is a method in which the means 17 receives light from the light emitting means 16 to detect the remaining amount of liquid.

In addition, in the mechanism shown in FIG. 3c, two conductors 18 are inserted into the liquid 15, and these are used as electrodes to detect resistance changes due to a decrease in the liquid 15. When the remaining amount becomes low, the resistance value suddenly changes. It takes advantage of the fact that the water rises.

However, such a conventional liquid remaining amount detection method cannot be used to detect the remaining amount of ink contained in a flat type ink storage container as shown in FIG. This is because this type of ink storage container is designed to minimize changes in the liquid level in order to keep the ink pressure constant. Furthermore, even with the mechanism shown in Figure 3c, even if the ink is low and completely gone, there is a risk that the resistance will drop due to ink adhering to the inside of the ink storage bag, so it is difficult to accurately detect the remaining amount of ink. I can't.

In addition, in Utility Model Application Publication No. 54-175362, ink 2 is supplied through an external pipe of a hollow needle for drawing out ink from an ink tank, and the inside of the needle is coated with an insulating film except for the tip. A configuration is disclosed in which a conductive rod 8 is incorporated, the rod is led out from the middle of the hollow needle, and the ink liquid level is detected by conducting/non-conducting between the rod and the hollow rod. There is.

However, if a space exists between the two electrodes consisting of a hollow needle and a rod, air bubbles may adhere between these electrodes, resulting in false detection. In other words, if bubbles generated due to gas dissolved in the ink become bubbles adhere to the space between the two electrodes, the electrical continuity between the electrodes will be cut off, and the ink will remain in the ink storage container. There is a problem that false detections occur even though there are sufficient numbers. Furthermore, since the space between the conductive rod 8 and the hollow needle 7 is relatively narrow, there is also the problem that once attached air bubbles are not easily removed and it is difficult to recover from a false detection state.

Furthermore, in Utility Model Application Publication No. 54-175362, the space between the two electrodes is just a space, so when piercing the ink tank bottom 4, one of the electrodes may obstruct the ink flow, or the two electrodes may may cause a short circuit.

Purpose: The present invention eliminates the above-mentioned conventional drawbacks, enables reliable detection of the amount of ink remaining in an ink container with a simple and inexpensive configuration, and allows safe and reliable attachment of the ink container to the ink container. An object of the present invention is to provide a residual ink detection device.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an ink residual detection device having a first and second ink residual detection electrode pair for detecting ink residual in an ink storage container used in an inkjet printer. The hollow needle is insertable into the ink storage container, the inner surface of the hollow needle is used as the first electrode, the outer surface is used as the second electrode, and an electrically insulating layer is inserted into the ink storage container along the longitudinal direction of the hollow needle. located between the inner and outer surfaces of the hollow needle up to the inserted tip,
Further, the cross sections of the tips of the first and second electrodes are configured to be on the same plane as the cross section of the tip of the hollow needle, and residual ink is controlled by the presence or absence of electrical continuity between the first and second electrodes. A detection configuration was adopted.

Embodiments Hereinafter, details of the present invention will be explained based on embodiments shown in the drawings.

Figures 4 and 5 illustrate an embodiment of the present invention, and in order to make the explanation easier to understand, a hollow needle provided on the main body side of the printer (not shown) is inserted into an ink cassette. It shows the condition.

In FIG. 4, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted.

The ink storage bag 1 built into the ink cassette 4 is provided with a lead-out pipe 5 at its end for leading the ink 2 to the printer body. It is held by a rubber stopper 6 fitted into the opening of the ink cassette 4.

On the other hand, a metal hollow needle indicated by the reference numeral 19 has an insulating member 2 inside a metal hollow needle 20 having a larger inner diameter.
1 and are inserted and fixed together. The hollow needle 19 has a longer overall length than the hollow needle 20, and the outer end of the hollow needle 19 has an ink 2 drawn out from the ink storage bag 1 through the outlet pipe 5 and the hollow needles 19, 20. An ink feed tube 23 is connected to guide the ink to the printer. Further, the metal hollow needles 19 and 20 are embedded and supported in an insulating holder 24, and the holder 24 is provided with holes 24a and 24b. The metal portions of the hollow needles 19 and 20 are electrically connected to the residual ink detection section 25 through these holes by conductive wires 26 and 27, respectively. Reference numeral 28 denotes a notification section that indicates the detection result detected by the detection section, and is composed of an optical display, an audible alarm, or the like.

Next, the operation of the present invention configured as above will be explained.

Figure 4 shows that the ink cassette containing the ink storage bag is mounted on the holding stand 24 on the printer body side as described above.
The rubber stopper 6 is connected by hollow needles 19 and 20 supported by
This shows a state in which ink is being supplied to the printer main body by piercing the ink, and shows a state in which there is a sufficient amount of ink remaining.

In this state, the inner surface of the metal hollow needle 19 and the outer surface of the hollow needle 20 are exposed to the conductive ink 2 filled in the hollow needle 19 and the lead-out pipe 5.
An electrically conductive circuit is formed between the residual ink detector 25 and the remaining ink detector 25 via the conductors 26 and 27, whereby the residual ink detector 25 detects the residual ink and sends a signal to that effect to the notification unit 28. , informs the user of the remaining ink.

On the other hand, FIG. 5 shows a state when the ink 2 contained in the ink storage bag 1 has been used up and there is little left. In this state, the ink 2 filled in the hollow needle 19 and the outlet pipe 5 shown in FIG. The electrical continuity between the two is broken, and the remaining ink detecting section detects this non-conducting state and sends a signal to that effect to the notification section 28 to notify the user that no ink remains.

As is clear from the above description, in the embodiment of the present invention, a three-layer structure is used in which an insulating member is sandwiched between a hollow needle for guiding ink from an ink cassette to the printer body, and the outer and inner surfaces of the hollow needle are made of metal. By adopting this method, two states of electrical conduction and non-continuity are created between the residual ink detection section and the residual ink depending on whether or not there is residual ink, thereby detecting the residual ink. To provide a residual ink detection device having a simple structure, low cost, high durability, and high accuracy without using movable parts lacking in precision and expensive light emitting and light receiving elements that are found in conventional residual ink detectors. I can do it.

In particular, in the above embodiment, an electrically insulating layer is located between the inner and outer surfaces of the hollow needle up to the tip on the side of the ink storage container, and there is no gap between the two where air bubbles may adhere. Furthermore, since the cross sections of the tips of the first and second electrodes on the outside and inside of the hollow needle are configured to be on the same plane as the cross section of the tip of the hollow needle, it is possible to detect a state in which there is no remaining ink, i.e. , the electrical conduction of the first and second electrodes is interrupted only at the cross section of the tip of the first and second electrodes, and there is no possibility of air bubbles adhering between the two electrodes and causing false detection. It is possible to reliably detect a decrease in the amount of ink remaining in the container.

Furthermore, an electrically insulating layer is located between the inner and outer surfaces of the hollow needle up to the blade surface at the tip on the side of the ink storage container, and there is no gap between the two where air bubbles may adhere. In a structure in which the cross-sections of the tips of the first and second electrodes are on the same plane as the cross-section of the tip of the hollow needle, the rigidity of the hollow needle is guaranteed, so that it is difficult to penetrate the rubber stopper of the ink storage container. Piercing can also be performed easily and safely without damaging the detection mechanism.

Effects As described above, according to the present invention, an electrically insulating layer is located between the inner and outer surfaces of the hollow needle up to the tip on the side of the ink storage container, and air bubbles are prevented from adhering between the two. There is no gap, and since the cross sections of the tips of the first and second electrodes on the outside and inside of the hollow needle are configured to be on the same plane as the cross section of the tip of the hollow needle, there is no space inside the ink storage container. This has excellent effects in that it is possible to reliably detect a decrease in the amount of ink remaining in the ink storage container, and to easily and safely penetrate the rubber stopper of the ink storage container without damaging the detection mechanism.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an ink cassette containing an ink storage bag in which the device of the present invention is used, Fig. 2 is a sectional view showing the structure of the ink storage bag shown in Fig. 1, and Fig. 3a.
-c are schematic explanatory diagrams showing a conventional residual ink detection device, FIG. 4 is a cross-sectional view showing the structure of the residual ink detection device according to the present invention when ink remains, and FIG. 5 is a diagram showing a residual ink detection device according to the present invention. FIG. 3 is a cross-sectional view showing a state where ink is exhausted. DESCRIPTION OF SYMBOLS 1...Ink storage bag, 2...Ink, 5...Leading pipe, 19, 20...Hollow needle, 21...Insulating member, 24...Holding stand, 25...Ink remaining detection unit, 28...Notification Department.

Claims (1)

[Scope of Claims] 1. An ink residual detection device having a pair of first and second electrodes for detecting residual ink for detecting residual ink in an ink storage container used in an inkjet printer, comprising: The inner surface of the hollow needle is the first electrode, the outer surface thereof is the second electrode, and the electrically insulating layer extends along the longitudinal direction of the hollow needle up to the tip that is inserted into the ink storage container. located between the inner surface and the outer surface of the hollow needle, and further configured such that cross sections of the tip ends of the first and second electrodes are on the same plane with a cross section of the tip end of the hollow needle, . An ink remaining detection device, which detects ink remaining based on the presence or absence of electrical conduction of a second electrode. 2. The ink storage container has an ink storage bag, a rubber stopper, and an outlet pipe connected to the rubber stopper and placed inside the ink storage bag, and the hollow needle is provided on the inkjet printer side. 2. The residual ink detection device according to claim 1, wherein the ink residual detection device is a hollow needle having a size that can be inserted into the lead-out pipe.