JPH08258280A - Ink residual amount detector of image forming apparatus - Google Patents

Abstract

PURPOSE: To always stably know an accurate ink amt. by providing a transparent member and the reflecting member arranged so as to leave a gap from the transparent member and detecting the amt. of ink on the basis of the position of the ink appearing between both members corresponding to the amt. of the ink in a tank. CONSTITUTION: A transparent plate 9 and a reflecting plate 8 are arranged at the outside position being in contact with the porous material 6 in an ink tank 5 so as to provide a gap 13 between both plates. An appropriate opening part is formed to the side wall of the ink tank 5 so as to be capable of looking the transparent plate 9 from the outside. The ink level in the porous material 6 appears as a region showing a black color in the gap 13 and the residual amt. of ink can be detected. As a detection means, a light reflection type sensor detecting the difference of reflectivity between the part of the reflecting plate 8 and the part where the ink showing a black color is present can be utilized.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for ejecting ink onto a recording material to form an image, and more particularly to an apparatus for detecting the amount of ink remaining in an ink tank.

[0002]

2. Description of the Related Art Recently, recording means for ejecting the ink in an ink tank to a recording material such as paper through a nozzle in accordance with an image signal to perform printing and image formation is low in cost and color. It is becoming more and more popular due to its ease of use.

In this type of recording means, it is essential that the amount of ink in the ink tank is constantly and accurately grasped and the ink in the tank is used effectively and to the maximum extent, which leads to a reduction in running cost. It is a requirement.

By the way, the ink jet type image forming means is roughly classified into an ink head portion for ejecting ink and an ink tank portion for storing ink. There is a case where the ink is stored as it is because it is necessary to reduce the pressure inside the ink so that the ink does not flow out from the head portion, but it is often stored in a state in which the porous member such as a sponge is impregnated with the ink. The present invention also relates to the latter.

As means for detecting the amount of ink in the ink tank, a dot counting method, an electrode detecting method, an ink tank temperature detecting method and the like have been proposed, which will be briefly described below.

The dot count method counts the number of control operations of ink ejection at the time of printing, and detects the ink consumption amount by this. However, when the ink tank or the head portion is removed from the apparatus main body for some reason, the count number up to that point is canceled and an accurate consumption amount cannot be obtained. It is not impossible to avoid such a situation by using the memory means, but this is not practical because it has a drawback that a huge amount of memory is required.

The electrode detection method is one in which two electrodes are arranged in an ink tank and the ink amount is detected by a change in the current flowing between the electrodes due to a change in the ink amount existing between them. However, it is practically difficult to accurately detect the change in the ink amount depending on the state of the ink, the state of the sponge impregnating the ink, and the like, and it is said that there is an error of about 30 to 50%.

Next, the temperature detection method will be described. In the ink jet method, the ink in the nozzle is vaporized and expanded by heating, and the ink is ejected and ejected by the pressure at this time. When the ink is in the ink tank, the ink is ejected. It does not rise above a certain temperature by its own cooling action.

However, when the ink in the ink tank is used up, the temperature of the ink head or the ink tank rises sharply, and this condition should be detected. However, in reality, this method cannot be said to be highly accurate.

As described above, various ink amount detecting means have been proposed in the past, but the present situation is that they are not yet effective in terms of accuracy and sensitivity. After all, it is practical that the operator of the image forming apparatus, the service person, etc. make the judgment visually, but this often has to be noticed after the ink is exhausted and the image cannot be formed. Further, since the recording unit including the ink head and the ink tank is not originally constructed so that the inside can be easily seen from the outside, it goes without saying that the above situation is not preferable.

The present invention has been made in view of the above circumstances, and the amount of ink in an ink tank of an image recording unit for impregnating and storing ink in a porous material such as a sponge is impregnated in the ink tank. A transparent member is provided in contact with the porous material, and a reflecting member is arranged with a small gap between the transparent member and the transparent member. The ink amount is detected by the position of the ink appearing according to the ink amount in the tank between them. It is an object of the present invention to provide an ink remaining amount detecting device configured so as to be able to constantly and accurately know an accurate ink amount.

[0012]

Configuration of the Invention

In order to achieve the above-mentioned object, the present invention provides an image formed by an ink jet system using a porous material built in an ink tank and impregnated and stored in the porous material. In the ink tank of the forming apparatus, a detection member composed of a transparent plate and a reflection plate disposed with a small gap between the transparent plate and the porous plate is arranged so that the gap can be seen from the outside. Ink remaining amount detecting device (1) of the image forming apparatus provided, or the ink according to (1) above, wherein the gap between the transparent plate and the reflecting plate is set to 0.050 to 0.100 mm. The remaining amount detecting device (2), or the ink remaining amount detecting device (3) according to the above (1) or (2), in which the upper and lower ends of the detecting member are formed in a tapered shape, or the above ( 1) to (3) In those of any one of a Tenku remaining amount detecting device transparent plate detecting member is an ink tank outer wall (4).

With such a configuration, it is possible to always stably and highly accurately detect the ink remaining amount in the ink tank with a simple configuration.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic perspective view of an ink head showing an embodiment of the present invention, the head 1 having nozzles 2 for ejecting ink. The nozzle is usually formed by arranging about 100 holes each having a diameter of about 20 μm. Reference numeral 3 is a nozzle substrate on which a heater board or the like for heating to eject ink from the nozzles is mounted and is fixed to the ink head body. Reference numeral 4 is a contact when the head 1 is mounted on a carriage or the like and is energized from the outside in order to control ink ejection. Reference numeral 5 is an ink tank, which is filled with a porous material such as sponge.

FIG. 2 is a perspective view of an essential part showing a part of the ink tank cut away, in which ink is impregnated and stored in the porous material 6 filled in the ink tank 5, and the nozzle 2 When the ink is ejected from the ink, the ink in the porous material 6 sequentially descends and reaches the nozzle 2 via the supply port 10.

A detecting member 7 is disposed in contact with the porous material 6 as shown in FIG. The detection member 7
Is composed of a transparent plate 9 arranged on the outer side and a reflecting plate 8 arranged with a small gap therebetween.

FIG. 4 is an enlarged side sectional view of the detection member 7. As described above, the porous material 6 in the ink tank 5
A transparent plate 9 is provided at an outer position abutting on the transparent plate 9, and a reflective plate 8 is provided with a gap 13 therebetween. Further, an appropriate opening is formed on the side wall of the ink tank so that the transparent plate 9 can be seen from the outside.

With such a structure, the ink level in the porous material 6 appears in the gap 13 like a portion shown in black in the figure, and the remaining ink amount can be detected.
As the detection means, a known light reflection type sensor that detects a difference in reflectance between the portion of the reflection plate 8 and the portion where the ink is present, which is shown in black in the drawing, can be used.

The width of the gap 13 is the viscosity of the ink, the capillary action, the surface tension, the hydrophilicity of the reflecting plate and the transparent plate, and
The size of the particles (granular space) of the porous material, the compressibility of the porous material, and the like are taken into consideration to set them appropriately.

Further, at least the lower ends of the reflector 8 and the transparent plate 9 are formed in a tapered shape as shown in the lower end of FIG. 4, so that an unnecessary space portion is not formed near this portion. Good to do.

In FIG. 4, a taper portion is not formed on the upper end portion of the detection member 7, but this is because the porous material 6 is formed at the corner portion of the detection member 7 by such a structure. It is intended to show where the space 14 is formed without a good fit.

As described above, particularly when the space is formed at the lower end of the detection member 7, the ink is accumulated in this part even if the ink level in the porous material is lowered, and the detection accuracy is deteriorated. May occur. Here, the shape of the upper end portion of the detection member 7 has less influence on the detection accuracy than the lower end portion, but may have the same tapered shape as the lower end portion.

By using such a detecting member, the gap 13 is set to 0.050 mm, 0.075 mm, 0.100.
When the experiment was conducted for the case of mm, the following results were found.

When the gap 13 is 0.050 mm, the gap 1
The ink level in 3 and the ink level in the ink tank almost matched. Also, almost the same result was obtained when the gap was 0.075 mm. The gap 13 is 0.100
In the case of mm, the ink in the gap was exhausted before the ink remaining in the ink tank was exhausted.

From these results, the conditions for enclosing the porous material 6 in the tank, the materials of the transparent plate and the reflection plate, the viscosity of the ink, etc. should be appropriately set by experiments in consideration of the above-mentioned conditions. Therefore, it can be seen that the remaining ink amount in the ink tank can be detected with high accuracy.

[0026]

As described above, according to the present invention,
The ink impregnated and stored in the porous material housed in the ink tank, the ink head that forms an image by ejecting from a nozzle according to an image signal, can detect the remaining ink amount in the ink tank with high accuracy and stability, It greatly contributes to the effective use of the ink head.

[Brief description of drawings]

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

FIG. 2 is a partially cutaway perspective view of the same.

FIG. 3 is a perspective view of a main part showing a detection member of the same.

FIG. 4 is an enlarged side sectional view showing the structure of the detection member of the above.

[Explanation of symbols]

 1 Ink Head Main Body 2 Nozzle 3 Nozzle Substrate 4 Contact 6 Porous Material 7 Detection Member 8 Reflector 9 Transparent Plate 10 Ink Supply Port 11 Tapered Part 13 Gap

Claims (4)

[Claims] 1. An ink tank of an image forming apparatus in which an ink is stored by impregnating and storing a porous material in an ink tank, the transparent material being in contact with the porous material. An ink remaining amount detecting device of an image forming apparatus, wherein a detecting member including a plate and a reflecting plate disposed with a small gap therebetween is disposed so that the gap can be seen from the outside. 2. The ink remaining amount detecting device according to claim 1, wherein the gap between the transparent plate and the reflecting plate is set to 0.050 to 0.100 mm. 3. An ink remaining amount detecting device according to claim 1, wherein at least a lower end portion of the detecting member is tapered. 4. The ink remaining amount detecting device according to claim 1, wherein the transparent plate of the detecting member is an outer wall of the ink tank.