JPH08187873A - Ink containing vessel and ink jet recording using the same - Google Patents

Abstract

PURPOSE: To improve the stability of reading of an optical sensor by improving the visibility of ink residue. CONSTITUTION: The ink residue detecting window 7 of an ink tank 1 having the window 7 at the part of a wall is formed of a plurality of cylindrical lenses 71 , 72 ,... having a longitudinal direction in a direction parallel to the ink liquid surface. Thus, the ink residue can be digitally displayed at a cylindrical lens unit. An optical sensor is disposed oppositely to the window 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink container for containing ink for ink jet recording and an ink jet recording apparatus equipped with the ink container.

[0002]

2. Description of the Related Art An ink jet recording apparatus comprises a recording head section for ejecting ink for recording, an ink supply section for supplying ink to the recording head, an ink tank section for storing ink, and the like. Of these, the role of the ink tank is not only to store the ink, but also to satisfactorily supply ink to the print head in proportion to the amount of ink ejected from the print head at the time of recording It is required not to cause ink leakage from the ink.

Conventionally, as an example of such an ink tank, as disclosed in Japanese Examined Patent Publication No. 63-63242, there is a type in which an ink tank is filled with a foam material (absorber).

By thus filling the absorber in the ink tank, a stable ink meniscus can be maintained in the ink ejection portion of the recording head, and the ink is held in the ink tank by the capillary force of the absorber. be able to. In this case, the absorber is filled almost all over the ink tank, and the amount of ink that is slightly smaller than the maximum amount of ink that the absorber can hold is held in the absorber so that the internal negative force is generated by using the capillary force. It is generating pressure.
Therefore, even when a mechanical shock such as vibration or a thermal shock such as a temperature change is applied to the recording head and the ink tank, there is little leakage of ink from the ejection portion of the recording head or the atmosphere communication portion of the ink tank, Can hold ink stably.

However, in the system in which the absorber is filled in the entire ink tank, the negative pressure of the absorber increases as the ink is consumed, and a large amount of ink remains in the ink tank without being supplied to the recording head. There is a problem that the efficiency is poor and that the absorber is dyed with ink, and it is difficult to know the remaining amount of ink from the outside.

As an example of a structure for solving the above-mentioned various problems in the ink tank constructed by filling the absorber in the ink tank in this manner, Japanese Patent Laid-Open No. 25835/1990.
The configuration of the ink tank disclosed in Japanese Patent Publication No. 3 is mentioned.

An outline of this structure is shown in FIGS. 9 (A), 9 (B) and 9 (C). Liquid ink is stored in the ink tank container without filling the absorber in the ink tank. It is filled directly. That is, as shown in FIG. 9, the ink tank in which the liquid ink is directly filled in the ink tank is the inkjet head cartridge 110.
Ink reservoir 112 and print head 13
In a part of the cylindrical portion 128 connecting 0 to 0, there is an orifice 136 as a first pressure control means for limiting the negative pressure of the ink reservoir 112, and the volume is further changed to obtain the negative pressure in the ink reservoir 112. It has a bag 126 as a second pressure control means for limiting the pressure. The ink jet head cartridge 110 further has an opening 142 as an ink filling port and a plug 144 embedded in the opening and sealing the same at the upper part thereof, and overflows the orifice 136 to store ink overflowing from the orifice 136. It has a reservoir 138 and a vent 140 that allows the overflow reservoir 138 to communicate with the atmosphere.

With this configuration, when ink is ejected from the print head 130 and consumed from the ink reservoir 112, the ink reservoir 112 is depressurized while the meniscus formed in the orifice 136 is maintained. As a result, a suitable negative pressure can be applied to the print head 130. Further, ink is continuously ejected and the negative pressure in the ink reservoir 112 increases, and when the threshold value is exceeded, the meniscus of the orifice 136 is broken, and air is introduced into the ink reservoir 112 from there, returning to a suitable negative pressure range. . By repeating this, good ejection of ink is executed.

[0009]

However, even in the ink tank that directly stores the liquid ink, the ink remaining amount from the outside is increased due to the swinging of the ink due to the movement of the carriage and the adhesion of the ink to the inner wall of the tank. There is a problem that it is often unclear. Particularly, in the type in which the ink level is read by an optical sensor provided in the ink jet recording apparatus, the liquid level is not constant, so that the sensor output constantly changes, and it is difficult to detect the remaining level and to warn the ink shortage.

Further, if the thickness of the ink tank is made thin in order to improve the visibility of the remaining ink amount, weight reduction, size reduction, and material cost reduction, the ink tank strength decreases, There was a case where the ink was deformed by an external force and ink leakage occurred.

An object of the present invention is to solve the above-mentioned various problems, to improve the visibility of the ink remaining amount in the ink container, and to improve the reading stability of the optical sensor and the like, as well as the external force. An object is to provide a strong ink container and an inkjet recording apparatus including the same.

[0012]

In order to achieve the above object, an ink container according to an aspect of the present invention is an ink container having a semi-transparent or transparent ink remaining amount detecting window on at least a part of a wall surface. In the above, the remaining ink amount detection window is constituted by a plurality of cylindrical lenses having a longitudinal direction parallel to the ink liquid surface.

An ink jet recording apparatus according to another aspect of the present invention is an ink jet recording apparatus in which the ink container is mounted, and an optical sensor provided opposite to the remaining ink amount detecting window, Means for detecting the remaining amount of ink based on the reading of the optical sensor.

[0014]

According to the ink container according to one aspect of the present invention, a plurality of semitransparent or transparent ink remaining amount detection windows provided on at least a part of the wall surface have a longitudinal direction in a direction parallel to the ink liquid surface. Since it is composed of a cylindrical lens, even if there is some fluctuation in the ink surface due to ink swing or ink adhered to the inner wall, the remaining ink level in the ink level detection window will be digitally displayed for each cylindrical lens unit. The liquid level is displayed. Therefore, it is possible to obtain a highly visible remaining amount display.

An ink jet recording apparatus according to another embodiment of the present invention is equipped with the above-mentioned ink container, and an optical sensor is provided so as to face the remaining ink amount detection window, so that reading can be easily performed. . Therefore, it is possible to reliably detect the remaining ink amount.

[0016]

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

(First Embodiment) FIG. 1 is a perspective view showing the configuration of the first embodiment of the present invention. Further, FIG. 2 also shows a sectional view thereof.

An ink container (hereinafter referred to as an ink tank) 1 has an ink supply hole 2 communicating with the recording head 10.
Is provided with a main body housing 3 formed at the bottom and a lid 4 covering the upper part of the main body housing 3. A filter 5 is provided upstream of the ink supply hole 2.
Further, the lid 4 is integrally formed with a thin tube 6 having an atmosphere communication port 6A for allowing the atmosphere to flow into the ink tank 1.
The opening 6B at the lower end is located near the bottom of the ink tank 1 so as to adjust the pressure by introducing the atmosphere at appropriate times so that the negative pressure in the sealed ink tank 1 does not become larger than necessary.

Further, 7 is an ink residual detection window formed on at least a part of the wall surface of the main body housing 3 of the ink tank 1, and has a plurality of longitudinally extending directions parallel to the liquid surface 8A of the ink 8 (in this example). , 8) cylindrical lenses 7 _{1 to} 7 ₈ .

The cylindrical lenses 7 _{1 to} 7 ₈ are convex toward the outside of the ink tank 1, and the inner side surfaces thereof are formed flat. The inner wall of the remaining ink amount detection window 7 (cylindrical lenses 7 _{1 to} 7 ₈ ) has a smaller surface roughness by polishing or the like, that is, is finished more smoothly than the other inner walls of the ink tank 1. By making the surface smooth in this way, the contact angle θ _R between the inner wall of the ink remaining amount detection window 7 and the ink 8 can be increased, and the liquid surface of the ink visually recognized from the outside of the ink tank 1 and the actual ink. The liquid surface 8A can be more closely matched.

In order to increase the contact angle, surface treatment such as water / oil repellency treatment may be applied to the inner surface of the ink remaining amount detection window 7 instead of the above polishing or the like.

Next, an example of an ink jet recording apparatus equipped with the ink tank 1 having the above structure will be described with reference to FIG.

Inkjet recording apparatus 10 in this example
0, the guide shaft 104 and the guide rail 10 arranged in the horizontal direction on the chassis 102 having a substantially U-shaped cross section.
A carriage 108 is guided in a reciprocating manner.
The carriage 108 includes an ink tank 1 and a recording head 1.
An ink jet recording head cartridge 110 obtained by combining 0 and 0 is mounted with the ejection surface of the recording head 10 on which the ejection ports are arranged facing downward. As is well known, the carriage 108 is reciprocated by a timing belt 112 driven by a motor. Further, as is well known, the ink jet recording apparatus 100 includes the recording head 1
0 is provided with signal supply means for supplying a control signal for ejecting ink, which is a flexible cable 11
It is supplied to the recording head 10 via 4.

A cap 116 made of a rubber member or the like is arranged at the home position to cover the entire ejection surface of the recording head 10 and, if necessary, a pump 118.
Is used for recovery processing by sucking thickened ink or the like from the ejection port.

Numeral 120 is a paper feeding tray, 122 and 124 are paper conveying rollers and pinch rollers,
Reference numeral 126 is a paper ejection roller for paper ejection, and 128 is a recording head 10.
Is a platen located below.

Next, 130 is the head cartridge 110.
Is an optical sensor arranged at the end opposite to the home position of the chassis 102 so as to face the remaining ink amount detection window 7, and is configured to be detected by a reflection type sensor using a photodiode, LCD, LED or the like. You can The optical sensor 130 is connected to a detection means (not shown), and the detection means displays the ink remaining amount read through the ink remaining amount detection window 7 through the display device or becomes less than a predetermined remaining amount. It can be made to warn by the warning means.

The operation of a plurality of continuous cylindrical lenses forming the ink remaining amount detection window 7 will be described with reference to FIGS. 3 and 4. The focal length f of the cylindrical lens is given by the following equation.

[0028]

F = r / (n-1) where r is the radius from the center 0 of the convex surface, and n is the refractive index of the material of the cylindrical lens. Therefore, by appropriately selecting these parameters, the focal point can be located on the inner surface of the cylindrical lens (shown by a point).

Therefore, each cylindrical lens 7 _{1 to} 7
_When the focal points of ₈ are displayed as a ₁ , a ₂ , ... According to the respective subscripts, for example, the liquid surface 8A is focused on the focal points a ₃ and a.
When it exists at the point b between ₂ and when it is visually observed from the direction parallel to the liquid surface 8A, regardless of whether it is between them,
An image cannot be seen by the third cylindrical lens 7 _3, but an image of the ink 8 can be seen entirely on the convex outer surface of the second cylindrical lens 7 ₂ .

FIG. 4 shows how the ink level 8A actually changes in the remaining amount detection window of the ink tank 1 as the remaining ink amount decreases.

FIGS. 4A and 4B show the case where the liquid surface 8A is displaced between the focal points a ₄ and a ₃ respectively, and in this case, the three cylindrical lenses 7 are used. the image of the ink 8 is visible in the entire _{1-7 3.} This is because even if the liquid surface 8A fluctuates between the focal points a ₄ and a ₃ due to the fluctuation of the ink 8 or the like, the change in the ink remaining amount display visible from the outside of the ink tank 1 does not change. Means no.

From this state, the consumption of the ink 8 progresses, and the state shown in FIG. 4C, that is, the liquid surface 8A is the focal point a ₃
At the lower side, the two cylindrical lenses 7 ₁ ,
Even if the display is switched to the ink remaining amount display by 7 ₂ and the liquid level 8A is further lowered as shown in FIGS. 4D and 4E, the display by these two lines does not change until the focal point a ₂ is exceeded. . Similarly, when the liquid surface 8A exceeds the focal point a ₂ , as shown in FIG. 4F, the remaining amount is displayed by only _one cylindrical lens 7 ₁ .

In this way, since the liquid level 8A can be displayed digitally by the number of cylindrical lenses regardless of the analog change, the ink remaining amount can be read by the optical sensor 130 described above. It is performed stably. Further, when the liquid surface 8A is near the focal point, the fluctuation of the liquid surface 8A due to the swing of the ink 8 or the like causes
The remaining ink amount display is changed digitally, but this can be positively utilized by electrical processing by the detection means. That is, it is possible to detect that the liquid surface 8A is located near the focus by detecting the change frequency of the remaining amount display and the like.

When the ink tank 1 is mounted on the ink jet recording apparatus 100, it is preferable to detect the remaining amount at a position where the direction of the optical sensor 130 is as parallel as possible to the liquid surface 8A. Is preferably performed at the home position where the ink tank 1 is farthest from the optical sensor 130.

However, it may be sufficient to detect the ink remaining amount only immediately before the ink runs out. Therefore, as shown in FIG. 7, the optical sensor 130 should be positioned below the ink remaining amount detecting window 7. Alternatively, the reading operation may be performed at a position close to the ink tank 1.

In the ink tank 1 having the above structure, printing was performed using the ink 8 having a viscosity of 1.8 cps and a surface tension of 48 dyn / cm, and the remaining ink amount was detected. Remaining ink amount detection window 7 has 15 pieces of the cylindrical lens 7 _{1-7 15} in this example, also formed integrally with the main body housing 3 with a polypropylene n = 1.5, r =
It was configured with 1 mm and f = 2 mm. Further, the inner wall of the ink remaining amount detection window 7 is mirror-polished, and the contact angle with the ink is θ _R = 80 ° at other portions, and θ _R = 1.
Raised to 00 °.

The ink jet recording apparatus 1 having the above structure
The ink tank 1 was mounted as the head cartridge 100 on the printer No. 00, and the recovery operation and the printing operation were repeated. First, 50 cc of the ink 8 was injected into the ink tank 1, and the liquid surface 8A thereof had a height of 25 mm. At this time, all the ₁₅ cylindrical lenses 7 _{1 to} 7 ₁₅ arranged at 1.6 mm pitch looked black. Then, when 25 cc is consumed, the seven upper lenses 7
_{9-7 15} becomes transparent, apparently remaining amount of ink was found to be decreased. Furthermore, if 20cc is consumed,
That is, when the remaining amount becomes 5 cc, only the lower two 7 ₁ and 7 ₂ become black, and even if there is almost no remaining amount, the remaining amount display is changed digitally and the highly visible remaining amount can be detected. It was

(Second Embodiment) The same ink tank as shown in FIG. 1 is used as in the first embodiment, and only the cylindrical lens portion has a half pitch with respect to the cylindrical lens shown in FIG. 3 as shown in FIG. Created with stuff. That is,
It is arranged at a pitch of 0.8 mm without changing the wall thickness. Also in this embodiment, the remaining amount display is changed digitally as in the first embodiment, and the remaining amount can be detected with extremely high visibility.

(Third Embodiment) A third embodiment shown in FIG. 8 is a cross-sectional view in which the present invention is applied to an ink container having a plurality of ink containing chambers. The main body housing 3 is divided into three chambers 3 ₁ , 3 ₂ and 3 ₃ by a partition wall 3
It is partitioned by _1-2 and 3 _2-3 , and each chamber contains different types of ink. The different types of ink may be different colors of yellow, magenta, and cyan, different shades of the same color, or a treatment liquid for improving various performances with the recording liquid.
In this embodiment, different colors of yellow, magenta and cyan are used, and all the ink containing chambers 3 ₁ , 3 ₂ and 3 are used.
₃ is configured so as to be guided to the ink remaining amount detection window 7 so that the ink surface can be seen. The remaining ink amount detection window 7 in this example is formed by attaching a plurality of cylindrical lenses to the outer surface of a transparent main body housing. Thus, even when the consumption amount of each color is different, the remaining amount of each ink can be seen at a glance, and the remaining amount can be digitally changed by the cylindrical lens, so that the remaining amount can be detected with high visibility. .

In the embodiment described above, the recording head 1
Although the cartridge type in which 0 is integrated with the ink tank 1 has been described, it goes without saying that the present invention can be applied to an ink tank separate from the recording head, and the same effect can be obtained. .

It is also clear that the amount of digital change can be arbitrarily determined by changing the focal length f or changing the material to change the refractive index n.

Further, in the present embodiment, the example in which the remaining amount detection window is provided on only one surface has been shown, but it is also possible to provide the remaining amount detection window on two or more surfaces to detect from all directions.

[0043]

As described above, according to the first aspect of the present invention, it is possible to provide the cylindrical lens without lowering the strength of the ink tank, and the cylindrical lens is digitally displayed. So
The visibility of the remaining amount of ink in the ink tank is significantly improved. Further, according to the second aspect of the present invention, the stability of the reading by the optical sensor is improved, and the remaining amount can be reliably detected.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is a partial enlarged cross-sectional view for explaining the operation of the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing how the display changes according to the change of the liquid level in the embodiment of the present invention.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a perspective view showing an example of an inkjet recording apparatus in which the ink tank of the present invention is mounted.

FIG. 7 is a sectional view showing a relationship with an optical sensor according to an embodiment of the present invention.

FIG. 8 is a sectional view showing a third embodiment of the present invention.

FIG. 9 is a cross-sectional view showing an example of a conventional ink tank.

[Explanation of symbols]

 1 Ink Tank 2 Ink Supply Hole 3 Main Body Housing 4 Lid 5 Filter 6 Thin Tube 7 Ink Remaining Detection Window (Cylindrical Lens) 8 Ink 8A Liquid Level 130 Optical Sensor

Claims (7)

[Claims] 1. An ink container having a semi-transparent or transparent ink remaining amount detection window on at least a part of a wall surface, the plurality of ink remaining amount detection windows having a longitudinal direction in a direction parallel to an ink liquid surface. An ink container comprising a cylindrical lens. 2. The ink container according to claim 1, wherein the cylindrical lens is a convex lens. 3. The ink container according to claim 1, wherein at least a part of the inner wall of the ink remaining amount detection window has a larger contact angle with respect to the ink than the other inner walls. 4. The ink container according to claim 3, wherein the difference in contact angle is caused by the difference in surface roughness. 5. The difference in the contact angle is generated by applying a water-repellent or oil-repellent treatment.
The ink container according to item 1. 6. The ink storage container is an ink storage container that stores a plurality of types of ink, and is partitioned so that the liquid level of each ink can be seen through the ink remaining amount detection window. The ink container according to claim 1. 7. An ink jet recording apparatus equipped with the ink container according to claim 1.
An ink jet recording apparatus comprising: an optical sensor provided opposite to the ink remaining amount detection window; and a unit for detecting the ink remaining amount based on the reading of the optical sensor.