JPH0542680A - Residual amount detector of ink tank - Google Patents

Abstract

PURPOSE:To provide an ink residual amount detector capable of visually and accurately confirming the residual amount of the ink in an ink tank filled with a porous material such as sponge. CONSTITUTION:An ink tank 4 is connected to the ink sub-tank 3 supplying ink to the printing head 1 attached to a heat sink 2 in a freely detachable manner. The ink tank 4 is loaded with sponge 5 to be filled with ink. A part of the wall surface of the ink tank 4 is constituted of an acrylic resin and several groove parts 7 different in capillary force are formed to the inner surface made of said acrylic resin. The state of the ink entering the grooves formed as capillary tubes is changed on the basis of the magnitude relation between the capillary force of the sponge and that of the grooves formed to the wall surface of the ink tank and the residual amount of ink can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly to a device for detecting the remaining amount of an ink tank which is detachably attached to a print head and supplies ink to the print head.

[0002]

2. Description of the Related Art As an ink remaining amount detecting device in an ink tank, as described in JP-A-2-3322, an electrode is provided in an ink tank to energize the electrode.
Many proposals have been made to detect the presence or absence of ink based on the value of the current flowing through the ink. Also in an ink jet cartridge of the ink tank separated type, the method disclosed in JP-A-2-19
As described in JP-A-8862, there has been proposed a device which detects the presence or absence of ink by an electrode provided on the head side. As an ink remaining amount detecting device, a device for detecting ink pressure, a device for detecting transmitted light of ink, and the like have been proposed in addition to a device for detecting a current value flowing in ink. As described in JP-A-58-194552, a simple mechanism for visually confirming the ink in the ink tank has also been proposed.

However, the above-mentioned conventional ink remaining amount detecting device has the following drawbacks. A device that detects the presence or absence of ink based on a current value needs to be detected by applying a pulsed voltage or an AC voltage in order to prevent electrolysis of the ink, and the detection circuit becomes complicated and expensive. In the ink cartridge of the ink tank separation type, the ink tank is disposable, but if the detection electrode is provided in the ink tank, the ink tank becomes expensive. Also,
If air bubbles are mixed in the head portion, the ink will be erroneously detected as the remaining amount is exhausted even if ink remains in the ink tank. Even if the detection is normally performed, the ink in the ink tank is depleted and the ink in the head is depleted. Therefore, there is a problem that air bubbles are likely to be mixed in the head when the remaining amount is detected. An ink cartridge of a conventional ink jet printer is disclosed in Japanese Patent Laid-Open No. 63-87242.
By storing the ink to be sent to the print head in an absorptive porous material such as polyurethane foam filled in the housing, it is possible to stably send the ink to the print head regardless of the vibration of the printer. is there. The remaining amount of ink contained in such a porous material is
It should be seen as a difference in the concentration of the porous material, but the ink cannot be completely exhausted from the porous material, and the porous material is dyed with an ink dye, so it cannot be visually confirmed with high accuracy. .. The current value flowing through the ink in the ink tank changes stepwise depending on whether or not the ink touches the electrodes, so that it is easy to detect. However, when a porous material such as a sponge that holds ink is filled in the ink tank, the electrical resistance of the porous material continuously changes depending on the ink content, so the criterion for determining the presence or absence of ink is It is not clear and it is difficult to increase the detection accuracy.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and accurately confirms the amount of ink remaining in an ink tank filled with a porous material such as sponge by visual observation. It is an object of the present invention to provide a remaining ink amount detection device that can be used.

[0005]

According to the present invention, in an ink tank filled with a porous material such as a sponge, at least a part of the wall surface of the ink tank is made of a light transmissive member, and the light transmissive member is used. It is characterized in that a groove having regions having different capillary forces is formed on the inner surface of the formed ink tank wall surface.

The grooves formed in the light transmissive member of the ink tank are a plurality of grooves having different depths and can be arranged in the order of depth. The inner surface of the groove formed in the light transmissive member of the ink tank may be roughened.

[0007]

[Function] When a capillary is brought into contact with the surface of the sponge containing ink, the state of the ink entering the groove formed in the capillary changes depending on the magnitude relationship between the capillary force of the sponge and the capillary force of the groove on the wall of the ink tank. To do. That is, the capillary force of the sponge is weak when the ink amount contained in the sponge is large, and is strong when the ink amount is small. When the capillary force inside the sponge is weak, the capillary force of the groove is superior, and the groove is filled with ink. When the wall surface of the ink tank is made of a light-transmissive member and the groove is viewed from the outside, the groove can be recognized as black and the ink inside the groove can be confirmed.

As the ink inside the sponge decreases, the capillary force inside the sponge increases. For example, if a plurality of grooves having different capillary forces are provided, the ink in the grooves having weak capillary force is absorbed by the sponge as the capillary force of the sponge increases. When the groove not filled with ink is visually observed from the outside, light is reflected on the inner surface of the groove, so that it is confirmed that the ink is exhausted inside the groove.

In this way, the groove in which the ink is visually recognized changes according to the amount of ink contained in the sponge, and the amount of ink remaining in the ink tank (sponge) can be known.

The porous material is, of course, disposed so as not to fill the inside of the formed groove, and the shape of the groove is determined by determining the width, the depth, or both. , Capillary force can be selected. As described above, a plurality of grooves having different capillary forces may be provided, or one groove may have different capillary forces in a stepwise or continuous manner.

[0011]

FIG. 1 is a schematic configuration diagram of an ink jet head for explaining an embodiment of an ink tank of the present invention. FIG. 1A is a perspective view, FIG. 1B is a front view, and FIG. The figure is a side view. In the figure, 1 is a print head, 2 is a heat sink, 3 is a sub ink tank, 4 is an ink tank, 5 is a sponge, 6 is an atmosphere communication hole, 7 is a residual quantity observation window, and 8 is a groove. The inkjet head is roughly composed of a recording head section and an ink tank having a large capacity that can be attached to and detached from the recording head section. The recording head unit includes a print head 1 and a heat sink 2 to which the print head is attached.
The sub ink tank 3 has a small capacity and contains a sponge, and a wiring portion (not shown) for supplying an electric signal to the print head. At least a part of the ink tank 4 is a transparent remaining amount observation window 7 so that the inside of the ink tank 4 can be observed. Ink tank 4
The inside is filled with sponge and ink, and the sponge is in a close contact state with being pressed against the transparent remaining amount observation window. The recording head unit and the ink tank 4 are connected by a joint, and the ink in the ink tank 4 is
It is supplied to the recording head unit via a joint. The ink in the ink tank is consumed with printing, and when the ink runs out, the ink tank is replaced and ink is supplied from the new ink tank to the recording head unit. Therefore, confirmation of the presence or absence of ink in the ink tank is important in determining the replacement time of the ink tank. The remaining amount observation window 7 of the ink tank 4 of this embodiment is made of acrylic and is configured as a transparent observation portion.

FIG. 2 is a cross-sectional view of a portion of the remaining amount observation window 7 cut in a direction perpendicular to the groove. The grooves 8 are sponge 5
Is formed on the surface in contact with. In this embodiment, the groove 8 has a semicircular cross section and a depth (radius) of 100 to 100.
It is 1000 μm. The sponge 5 contained in the ink tank is a urethane foam or PVA foam having a pore size of about 300 μm and a porosity of about 80%. Initially, the ink tank 4 is filled with ink of about 70% of the tank capacity. In this state, all the groove portions 8 provided in the transparent observation portion of the remaining amount observation window 7 are filled with ink, and the fact that the groove portions 8 are filled with ink is observed through the transparent observation portion.
As the ink is consumed, the ink in the deep groove portion will be sponge 5
When the ink is reduced to about 20% of the initial amount, the ink is no longer observed in the groove having a depth of 200 μm or more. It is at this level that printing deteriorates due to lack of ink, and whether or not a groove having a depth of 200 μm is filled with ink can be used as an index indicating the time to replace the ink tank.

An outline of the relationship between the ink consumption and the groove depth is shown in FIG. The horizontal axis represents the remaining ink amount (%), and the vertical axis represents the relative depth of the groove. The relationship between the remaining amount of ink and the filling of the groove with ink varies depending on the material of the remaining amount observation window, surface roughness, sponge density, sponge material, and the like. As the material of the wall portion of the remaining amount observation window, glass, polycarbonate, or the like can be used in addition to acrylic. However, the material of the wall portion does not have to be completely transparent as long as it is translucent. For example, a material that is cloudy may be used.

The cross-sectional shape of the groove is shown in FIG. 2A, V-shaped groove 8a shown in FIG. 4A, rectangular groove 8b shown in FIG. 4B, and FIG. 4C in addition to the semicircular groove shown in FIG. The groove 8c having a shape obtained by combining the V-shape and the rectangle may be used. These grooves may have different widths and / or depths to change the capillary force. In the case of a rectangular groove, it is easy to change the width or depth independently. In the case of V-shaped groove,
By changing the apex angle, the width or depth can be changed independently. These grooves are provided so that the sponge 5 does not enter the grooves.

When the surface of the groove is roughened finely, light is diffusely reflected at the interface of the groove, and the presence or absence of ink filling in the groove can be seen with high contrast.

When the grooves are arranged in order from shallow grooves to deep grooves as shown in FIG. 5, the remaining amount may be easily visually recognized. In this way, when a plurality of grooves are provided, the arrangement order can be appropriately arranged such as bottom to top, top to bottom, right to left, left to right. The direction of the groove is
As described with reference to FIG. 1, not only the horizontal direction but also the vertical direction or the inclined direction as shown in FIG. The shape may be concentric as shown in FIG.

One groove may be used, and the width or depth of the groove or both of them may be changed stepwise or continuously.

[0018]

As apparent from the above description, according to the present invention, the inside of the sponge is not directly detected but the inside of the groove provided on the wall surface of the ink tank formed of the light transmissive member. Since the ink is visually checked, the judgment is certain. Further, since the structure is simple in that only a groove is provided on the wall surface of the ink tank and no special electrode or detection circuit is required, there is an effect that it is inexpensive.

Further, since the remaining amount of ink in the ink tank, not in the recording head portion, can be detected, highly accurate detection can be performed. The use of the groove having the regions having different capillarity has an effect that the consumption of the ink in the ink tank can be quantitatively detected, not as binary information.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention,
(A) is a perspective view, (B) is a front view, and (C) is a side view.

FIG. 2 is a cross-sectional view of an embodiment of a remaining amount observation window.

FIG. 3 is an explanatory diagram of a relationship between an ink consumption amount and a groove depth.

FIG. 4 is a cross-sectional view of an example in which the shape of the groove is different.

FIG. 5 is a cross-sectional view showing an arrangement order of grooves according to an embodiment of the present invention.

FIG. 6 is a front view showing an arrangement direction of grooves according to another embodiment of the present invention.

FIG. 7 is a plan view showing the arrangement of another embodiment of the present invention.

[Explanation of symbols]

1 print head, 2 heat sink, 3 sub ink tank, 4 ink tank, 5 sponge, 6 atmosphere communication hole, 7 remaining amount observation window, 8 groove part.

Claims (1)

[Claims] 1. In an ink tank filled with a porous material such as a sponge, at least a part of a wall surface of the ink tank is made of a light-transmissive member, and an inner surface of the ink tank wall surface made of the light-transmissive member. A remaining amount detecting device for an ink tank, wherein a groove having regions having different capillarity is formed in the ink tank.