JPH1148494A - Apparatus for detecting residual amount of liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the title apparatus for accurately detecting the presence and residual amt. of a liquid by analogously detecting the residual amt. of the liquid over a wide range. SOLUTION: Ink 20 is introduced into a light permeable tank 10 having a corner part 10a provided to a bottom part thereof and a sensor 30 having a light injection part 31 and a light receiving part 32 is obliquely arranged to the corner part 10a of the tank 10 and the light from the light injection part 31 is obliquely applied to the corner part 10a of the tank 10 from above and, on the basis of the increase and decrease change in the quantity of the light transmitted through the bottom part of the tank 10 to be incident on the light receiving part 32, the residual amt. of the ink 20 in the tank 10 is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid remaining amount detecting device which continuously (analogically) detects a change in the amount of liquid in a container and accurately detects the presence / absence and remaining amount of liquid.

[0002]

[Prior art]

<Prior Art 1> As a measuring device for detecting the amount of liquid in a container, there is generally a device for detecting a liquid level of a liquid 70 in a circular pipe 60 with a sensor 80 as shown in FIG. . As the amount of the liquid 70 increases, the liquid level rises.
The presence or absence of the liquid level is detected by the sensor 80. Sensor 80
Has a light projecting unit 81 and a light receiving unit 82, and the light from the light projecting unit 81 is irradiated on the pipe 60, and a change in the amount of light received by the light transmitted through the light receiving unit 82 changes the light projecting unit 81 and the light receiving unit 82. It is detected whether the liquid surface is above or below the optical axis connecting.

On the other hand, an ink cartridge (container) used for an ink jet printer or the like is often a rectangular body as shown in FIG. 30 (a), and when an ink (liquid) 70 in the ink cartridge 61 is detected. , FIG. 29
30A, it is conceivable to dispose the sensor 80 at a corner (here, a curved corner) of the ink cartridge 61 as shown in FIG. That is, light parallel to the liquid surface is emitted from the light projecting portion 81 to the ink cartridge 6.
1, the light transmitted through the ink cartridge 61 is received by the light receiving unit 82, and the amount of the received light changes to determine whether the liquid surface is above or below the optical axis position connecting the projecting / light receiving units 81 and 82. To detect. <Prior Art 2> FIG. 31 shows an example of detecting ink in an ink cartridge used in an ink jet printer or the like.
Shown in Here, tanks 1, 2, 3, and 4, each containing a sponge 63 and containing ink therein, are arranged, and these tanks 1 to 4 constitute a cartridge 62. The sponges 63 of the tanks 1 to 4 are moistened by the ink (soaked in the ink). The cartridge 62 is provided on the print head side, is movable in the X direction, and the reflection type sensor 90 is installed on the printer main body side.
By moving the cartridge 62, one sensor 9
At 0, the presence or absence of ink in the tanks 1 to 4 is detected.

Here, a sensor 90 detects each of the tanks 1 to
The bottom of 4 is irradiated with light, the reflected light is received, and the presence or absence of ink in the tanks 1 to 4 is detected based on the reflectance. That is, the presence or absence of ink is detected based on the difference in reflectance between the sponge 63 immersed in the ink and the sponge 63 in the dry state.

[0005]

[Problems to be solved by the invention]

<Problem 1> In the measuring device having the configuration as shown in FIG. 29 or FIG. 30A, only the liquid level of the liquid 70 is detected.
Only a binary signal indicating the presence or absence of the liquid 70 is detected. That is, in FIG. 30B, the light projecting unit 81 and the light receiving unit 82 of the sensor 80 have the light projecting lens 83 and the light receiving lens 84, respectively, and the detectable range by these is at most a maximum of both the lenses 83 and 84. Up to diameter D, liquid 7
It is difficult to detect the remaining amount of 0 continuously (in an analog manner) over a wide range. <Problem 2> In FIG. 31, the cartridge 62 may have to be moved in the Y direction or the Z direction due to the thickness of the printed material, etc., the light intensity of the sensor 90 may be reduced, and the light emitting / receiving lens may become dirty. Occurs, and the output obtained from the sensor 90 tends to fluctuate.
In such a case, it is difficult to stably and accurately detect the presence / absence of ink in combination with the fact that the output ratio between ink presence and ink absence is originally small.

This will be described in detail with reference to FIG. In FIG. 32A, assuming that the tank 2 has ink and the tank 1 has no ink, the output of the tank 1 becomes low and the output of the tank 2 becomes high. There is a difference between the obtained sensor outputs, and if a threshold value is set between the two outputs, the presence or absence of ink can be accurately detected if there is no change in the initial state.

However, a change in the distance between the cartridge 62 and the sensor 90, a decrease in the amount of light from the sensor 90,
When the initial state changes due to contamination of the light receiving lens or the like, the sensor outputs of the tanks 1 and 2 decrease (see FIG. 32B). At this time, if the threshold value is constant in the initial state, the sensor output from the tank 2 may fall below the threshold value. In this case, there is an erroneous determination that it is determined that there is no ink even though the tank 2 originally has ink.

Further, the reflection type sensor 90 is easily affected by the color of an object (ink) to be irradiated with light, which makes the detection of the presence or absence of ink unstable. For example, in the case of a dark color (black color), the amount of light absorbed by the ink increases, and in the case of a light color (white or yellow color), the amount of light reflected by the ink increases. The detection sensitivity differs depending on the type. <Problem 3> In the case of a measuring device having a configuration as shown in FIGS. 29 and 30 (a), a binary signal indicating the presence or absence of the liquid (ink) 70 is detected. The ink cartridge 61
There is a problem that it is not possible to accurately determine whether the ink 70 is present or only one ink is attached to the ink droplet attached to the inner wall.

For example, in the above-described measuring device, the presence or absence of the ink 70 is determined according to a flowchart as shown in FIG. In step (hereinafter abbreviated as ST) 21, the liquid level of ink 70 is measured by sensor 80, and the level of the measured value (detection signal) is determined (ST 22). If the measured value is low, it is determined that there is no ink. (ST23) If the measured value is high, it is determined that there is ink (ST24). However, in such an algorithm, even if an ink droplet is merely attached to the inner wall of the ink cartridge 61, the ink 70
May be erroneously determined.

The present invention has been made in view of such problems 1, 2 and 3, and detects the remaining amount of liquid in a wide range in an analog manner, and accurately detects the presence / absence and remaining amount of liquid. It is an object of the present invention to provide a liquid remaining amount detection device that realizes detection and accurately distinguishes a liquid droplet from a liquid.

[0011]

According to a first aspect of the present invention, there is provided an apparatus for detecting a remaining amount of a liquid, comprising: a light-transmitting container having a corner at a bottom portion for storing a liquid; A sensor having a light-receiving unit that receives light from the light-emitting unit and the light-emitting unit is disposed at the corner of the container bottom, and irradiates the light from the light-emitting unit to the corner of the container bottom at an angle. It is characterized in that the remaining amount of the liquid in the container is measured based on the increase or decrease in the amount of transmitted light that passes through the container and enters the light receiving unit.

According to a second aspect of the present invention, there is provided a liquid remaining amount detecting apparatus, comprising: a light transmitting container for storing a liquid; a light projecting unit; and a light receiving unit for receiving light from the light projecting unit and detecting a position of a light receiving spot. And a sensor having a sensor, and irradiates the container with light from the light projecting portion obliquely to a horizontal plane, and transmits the inside of the container and changes the optical axis of the transmitted light incident on the light receiving portion in the container based on the vertical change. It is characterized in that the remaining amount of the liquid is measured.

According to the first aspect of the present invention, the light from the light projecting portion is obliquely applied to the corner at the bottom of the container, and the light is transmitted through the container and incident on the light receiving portion. Since the remaining amount of liquid in the container is measured, the apparatus according to claim 2 irradiates the container with the light from the light projecting portion obliquely to the horizontal plane, transmits the light through the container and enters the light receiving portion. Since the remaining amount of liquid in the container is measured based on the vertical change of the optical axis, the remaining amount of liquid can be detected analogously over a wide range, thereby accurately detecting the presence / absence and remaining amount of liquid it can.

On the other hand, a liquid remaining amount detecting device according to a fifth aspect of the present invention provides a light transmissive container for storing a liquid, a container that can be used as a reference with liquid, a container that can be used as a reference with no liquid, and a light projecting unit. And a light-receiving unit, and a reflection-type sensor that irradiates the container with light from the light-emitting unit and receives reflected light from the container at the light-receiving unit. It is characterized in that the presence or absence of liquid in the container is determined by using the sensor output obtained from each container as a relative output.

According to a fifth aspect of the present invention, a reflection type sensor is combined with a reference container having a liquid and a reference container having no liquid, and sensor outputs respectively obtained from the reference container having a liquid and the reference container having no liquid are provided. Is used as a relative output to determine the presence or absence of liquid in the container, so that the presence or absence of liquid can be accurately detected. In addition,
In the configuration of the first and second aspects, measuring the remaining amount of the liquid includes the following. This is to detect (measure) the amount of liquid continuously, for example, in a container having a capacity of 15 cc, and the remaining amount of liquid is 3 to 1 c.
An analog signal is output between c. This is to detect (measure) the remaining amount of the liquid continuously, for example, in a container having a capacity of 15 cc and the remaining amount of the liquid is 2 to 0 c.
An analog signal is output between c. Digitally detecting a decrease in the remaining amount of liquid This is to detect the remaining amount of liquid in multiple stages. For example, in a container having a capacity of 15 cc, the amount of remaining liquid is between 2 and 0 cc in increments of 0.2 cc. Output (as a digital signal). Detecting whether or not a predetermined amount of liquid remains This is a binary output, for example, when the remaining amount of liquid is 0.5c
If it is larger than c, a signal is output, and if it becomes 0.5 cc or less, no signal is output. Detecting whether or not the liquid is equal to or more than a predetermined amount This is also a binary output.
When the number is larger than c, the signal is not output, and the signal is output only when it becomes 0.5 cc or less. Note that the result is the same except that the output method is different.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a schematic configuration diagram illustrating a basic concept of a liquid remaining amount detection device according to an embodiment. The light-transmitting container (tank) 10 shown in FIG. 1 corresponds to the tank 6 shown in FIG.
The tank 1 is turned upright (see Fig. 2).
The arrow A side of 0 is the upper side, and the light transmissive liquid (ink) 20 inside decreases in the direction of arrow B, and the sensor 30 is obliquely fixed and arranged at the corner 10 a at the bottom of the tank 10. The sensor 30 is configured such that the light projecting unit 31 and the light receiving unit 32
It is positioned so as to oppose it with the zero corner portion 10a interposed therebetween. Therefore, the light from the light projecting portion 31 of the sensor 30 is obliquely incident on the corner 10 a of the tank 10 from above, passes obliquely through the bottom of the tank 10, and is incident on the light receiving portion 32. Although the corner portion 10a of the tank 10 has a curved shape here, the shape may be a right angle, and any shape may be used as long as light refraction occurs depending on the presence or absence of the liquid 20 and the light refraction can be detected.

When the apparatus having such a configuration is applied to an ink jet printer or the like, the arrangement is as shown in FIG. Here, sponges (not shown) are respectively accommodated, and tanks 1 to 4 containing four different color inks respectively.
Thus, the ink cartridge 12 is configured. However, the sponge does not necessarily need to be accommodated, and the tanks 1 to 4 without sponge may be used. The ink cartridge 12 is mounted on the print head side and is integrally movable in the direction of the arrow. The sensor 30 is installed on the printer body side,
Light is applied to the corners at the bottom of each of the tanks 1 to 4, and the transmitted light is received.

In this case, the presence or absence and the remaining amount of each ink in a plurality (four) of the tanks 1 to 4 can be detected by one sensor 30 by moving the ink cartridge 12. In addition, since the optical refraction phenomenon is used, it is hardly affected by the color (shade) of the ink.
The presence / absence and remaining amount of ink can be accurately detected.
By the way, in the case of an apparatus employing the detection concept as shown in FIGS. 29 and 30 (a), one sensor is required for each tank, and when a reflection type sensor is used as shown in FIG. Are susceptible to the color of the ink.

With such an arrangement of the tank and the sensor 30, the relationship between the remaining amount of ink in the tank and the output change of the sensor 30 is as shown in FIG. In FIG. 4, a straight line is an output change obtained by the configuration of the embodiment, and a straight line is
This is an output change obtained by the configuration of FIG. According to this, even with the same output change width, the output change of the straight line (slope portion a) is gentler than the output change of the straight line (slope portion b), and the change in the remaining amount of ink can be continuously detected over a wide range. I understand. That is, while the conventional configuration is digital detection, the configuration of this embodiment is analog detection.

Next, the detection operation of the above device will be described with reference to FIGS.
A description will be given with reference to FIG. 7 (partially enlarged sectional view), and FIG. 8 shows a detection concept in the configuration of FIG. The arrow “up” in the figure indicates that the tank 11 is above. The sensor 30 detects that the light L from the light projecting unit 31 is obliquely incident on the bottom of the tank 11 from above and the light receiving unit 32 facing the light projecting unit 31 receives the light L transmitted through the tank 11. Are positioned so that

In FIG. 5, when the tank 11 is sufficiently filled with the ink 20, the light L from the light projecting unit 31 is refracted by the tank 11 and is incident on the ink 20 inside, and the ink 20 is linearly changed as it is. And refracts again when exiting from the tank 11. In this case, the light L emitted from the tank 11 hardly enters the light receiving unit 32, and the light receiving unit 32 does not detect light reception. Based on this, the ink 20 is stored in the tank 1
1 (see FIG. 8A).

In the state of FIG. 5, the ink 20 gradually decreases,
When the liquid level falls, the state shown in FIG.
Then, the light L is refracted twice by the tank 11 and enters the inside, travels straight through the internal space, is refracted by the ink 20, is further refracted by the tank 11, and is emitted from the tank 11. In this case, since a part of the light L gradually enters the light receiving unit 32, the light receiving unit 32 detects a small amount of received light. In this state, although the ink 20 still remains in the tank 11, it is determined that the remaining amount is small (see FIG. 8B).

When the ink 20 in the tank 11 is completely exhausted as shown in FIG.
Twice, and is refracted twice at the time of emission, and enters the light receiving unit 32 entirely.
The light receiving unit 32 detects a large amount of light received. Thus, it is determined that the ink 20 in the tank 11 has completely run out (see FIG. 8C). As is apparent from this detection operation, the apparatus of the embodiment utilizes the refraction phenomenon of each light of the tank 11, the air in the tank 11, and the ink 20, and in order to effectively utilize the refraction phenomenon, Tank 11
The light L is radiated to the corner portion at the bottom of the. With such a configuration, it is possible to continuously detect a change in the remaining amount of the ink 20 in the tank 11 over a wide range,
In addition to the presence or absence of the ink 20, the remaining amount can be detected in an analog manner.

FIG. 9 schematically shows a liquid remaining amount detecting device according to another embodiment. FIG. 9 shows an ink cartridge 12 such as an ink jet printer.
Has an ink-free reference tank 5 containing no ink, and an ink-filled reference tank 6 filled with ink, in addition to tanks 1-4. Located on both sides. Note that FIG. 9 shows the sponge 13 only for the tank 6, but all the tanks 1 to 6 contain sponge respectively.

Here, in order to make the explanation easy to understand,
The tanks 5 and 6 have the same shape and structure as the tanks 1 to 4. However, the tanks 5 and 6 only need to be in a position that can be detected by the reflection type sensor 40 in conjunction with the tanks 1 to 4, By doing so, it is also possible to reduce the installation space. For example, in FIG. 10, the tank 4 has the shape as shown, the reference tank 5 without ink is arranged beside the tank 1, and the reference tank 6 with ink is arranged below the tank 4.

In any case, the ink cartridge 12 composed of the tanks 1 to 6 is mounted on the print head side and is movable in the direction of the arrow. The reflection type sensor 40 having a light projecting unit and a light receiving unit is installed on the printer body side, irradiates light to the bottom of each of the tanks 1 to 6, and receives the reflected light. This device differs from the conventional device shown in FIG. 31 in that it has a reference tank 5 without ink and a reference tank 6 with ink. Therefore,
If the reference tanks 5 and 6 with no ink and with ink are used, detection as shown in FIGS. 11 and 12 can be performed.

That is, in FIG. 11, the output of the reference tank 6 with ink obtained from the reference tank 6 with ink, the output of the tank 2 with ink, the output of the reference tank 5 with no ink obtained from the reference tank 5 without ink, and no ink The output of tank 1 is
It is assumed that each is at the level as shown. The output level based on ink is referred to as output 1 and the output level based on no ink is referred to as output 2. Here, if the threshold value as a criterion for determining the presence / absence of ink is (output 1 + output 2) / 2, the threshold value is located between output 1 and output 2, so that the presence / absence of ink can be detected.

On the other hand, when a change in the initial state, that is, a change in the distance between the cartridge 12 and the sensor 40, a decrease in the light amount of the sensor 40, and contamination of the light projecting / receiving lens occur, as shown in FIG. , 2, 5, and 6 sensor outputs decrease. If the threshold value is constant in the initial state, an erroneous determination may occur as described above. However, if the threshold value is set to an intermediate value between the output 1 and the output 2 even if the output fluctuates, the threshold value may be changed according to the output fluctuation. As a result, the threshold value also changes relatively, so that an erroneous determination that ink is not present in a tank that has ink does not occur. Therefore, the presence or absence of the ink in the tank can be accurately detected.

The apparatus shown in FIGS. 1 and 3 uses an A / D converter or the like for detecting the amount of light in an analog manner in order to detect the remaining amount of the liquid (ink) in an analog manner as described above. I have. Droplets and liquids can be accurately distinguished from the magnitude of the analog amount obtained from the A / D converter. FIG. 13 shows the algorithm. First, S
At T1, the remaining amount of ink in the container (tank) is measured, and the level of the measured value is determined (ST2). If the measured value is low, it is determined that there is no ink in the tank (ST
3).

On the other hand, if the measured value is high, the measured value is stored in the memory 1 (ST4). Next, the tanks are moved (ST5). In the ink jet printer, each tank can be moved by moving the ink cartridge. After the tank is moved, the remaining amount of the ink is measured again (ST6), and the measured value is stored in the memory 2 (ST7). Then, the output difference between the memory 1 and the memory 2 is obtained, and the magnitude of the output difference is determined (ST8). If the output difference is small, there is no large difference in output even before and after the movement of the tank, so it is determined that the tank is sufficiently filled with ink (ink is present) (ST
9). If the output difference is large, there is a large difference in output between before and after the movement of the tank, so it is determined that ink droplets have adhered to the inner wall of the tank (no ink) (ST10).

According to this flow chart, particularly in an ink jet printer, the fact that the ink cartridge frequently moves during printing is used, and the output before and after the movement is compared, so that the presence or absence of ink can be more easily determined. can do. In other words, if the output change before and after the movement is large,
It can be determined that the ink droplet has moved based on the acceleration at the time of movement,
If the output change before and after the movement is small, it is determined that the ink droplet has not moved (it is not ink droplet but liquid ink).

FIG. 14 is a schematic configuration diagram showing a basic concept of a liquid remaining amount detecting device according to still another embodiment. The embodiment shown in FIG. 1 irradiates the light obliquely to the corner 10a of the tank 10, whereas the embodiment shown in FIG.
From one side to the other side (ink 2
(Light level 0) is irradiated obliquely with light. The light-transmitting tank 10 shown in FIG. 14 is a normal one, and the light-transmitting ink 20 in the tank decreases in the direction of arrow B,
3 extending from one side to the other side of the sensor 3
5 are fixed and arranged. The sensor 35 includes a light emitting unit 36
And the light receiving portion 37 are positioned so as to face each other with the tank 10 interposed therebetween. Therefore, the light from the light projecting unit 36 of the sensor 35 is obliquely incident on one side surface of the tank 10, passes through the other side surface, and is incident on the light receiving unit 37.

An element (PSD: Position Sensitivity) for detecting a vertical change of the optical axis of the transmitted light (a change in the position of the light receiving spot on the light receiving element (a change in the center of gravity, etc.)) is provided to the light receiving section 37 of the sensor 35.
FIG. 15 is a block diagram showing an example of signal processing when the tiveLight Detector (50) is used. In this block diagram, the signals from the PSD 50 are respectively supplied to the amplifier 51,
The signals are amplified by 52 and become outputs v1 and v2. The amplified signals are converted into digital signals by A / D converters 53 and 54, and one of them is converted into a signal v1 + v2 55, and a predetermined operation [v2 (v1) / (V1 + v2)] is performed,
The value is output. Note that the operation formulas include the following examples in addition to the example shown in FIG.

V2 / v1 (v1-v2) / (v1 + v2) (v2-v1) / (v2 + v1) Also, for example, in order to notify a decrease in the remaining amount of ink, the output from the computing unit 56 is used as a reference value. And may be binarized (digitized).

By the processing of the light receiving signal as shown in FIG. 15, the relationship between the remaining amount of the liquid (ink 20) in the tank 10 and the output change is inversely proportional as shown in FIG. 16 is a clean straight line, but it is not actually a perfect straight line.) This makes it possible to continuously detect a change in the remaining amount of the liquid over a wide range. That is, while the conventional configuration is digital detection, the configuration of this embodiment is analog detection. Here, the PSD 50 is used for the light receiving unit 37, but a multi-division PD (Photo Diode, line sensor), a CCD (Charge
A Coupled Device, a one-dimensional image sensor) or the like may be used.

Next, the detection operation of the above device will be described with reference to FIG.
20 to FIG. 20 (partially enlarged sectional view), and FIG. 21 shows a detection concept in the configuration of FIG. The sensor 35 is positioned such that the light L from the light projecting unit 36 is obliquely incident upward from one side surface of the tank 11, and the light receiving unit 37 facing the light projecting unit 36 receives the light L transmitted through the tank 11. Have been. The size of the light receiving element of the light receiving section 37 is the same as the diameter of the light projecting lens of the light projecting section 36, and a lens or a pinhole is provided in front of the light receiving element. Note that the light projecting unit 36 may be arranged on the upper side and the light receiving unit 37 may be arranged on the lower side, and the incident direction of the light L may be inclined downward.

In FIG. 17, when the tank 11 is sufficiently filled with the ink 20 (the ink level 20a shown in FIG. 14).
The light L from the light projecting unit 36 is refracted by the tank 11 and is incident on the ink 20 inside, passes straight through the ink 20 as it is, and is refracted again when emitted from the tank 11. In this case, the light L emitted from the tank 11 is
7 is incident on the upper part. Based on this, it is determined that the ink 20 is sufficiently contained in the tank 11 [(a) of FIG.
reference〕.

In the state shown in FIG. 17, when the ink 20 gradually decreases and its liquid level falls, the state shown in FIG. 18 is reached (see the ink liquid level 20b in FIG. 14). Then, light L
Is refracted by the tank 11, travels straight through the ink 20 as it is, is refracted by the liquid surface of the ink 20, and is refracted twice by the tank 11 to be emitted. In this case, the light L is transmitted to the light receiving section 37.
Gradually enters the lower part of. In this state, although the ink 20 still remains in the tank 11, it is determined that the remaining amount is small (see FIG. 21B).

As shown in FIG. 19, the ink 20 in the tank 11 is
When the light L is incident near the liquid level of the above, a part of the light L is refracted twice when entering the tank 11 and twice when exiting, and does not enter the light receiving portion 37 at all. The remainder of the light L is shown in FIG.
The light is refracted and exits the tank 11 in the same manner as in the state 8, and enters the lower part of the light receiving section 37. Thereby, it is determined that the ink 20 in the tank 11 is almost exhausted [(c) of FIG.
reference〕.

As shown in FIG. 20, the ink 20 in the tank 11 is
Is further reduced (see the ink level 20c in FIG. 14), the light L
Are refracted twice when entering the tank 11 and twice when exiting, and do not enter the light receiving portion 37 at all. In this case, it is possible to determine that the remaining amount of the ink 20 in the tank 11 is equal to or less than a certain amount by performing the determination processing together with the amount of light L received.

As is apparent from this detection operation, the apparatus of this embodiment is similar to the above-described embodiment in that the tank 11,
The refraction phenomenon of air and ink 20 in the tank 11 is utilized. In order to effectively utilize the refraction phenomenon, light L is applied to the side surface of the tank 11 with respect to a horizontal plane (the liquid level of the ink 20). Irradiation at an angle. With such a configuration, it is possible to continuously detect a change in the remaining amount of the ink 20 in the tank 11 over a wide range, and to determine whether the amount of the ink 20 is equal to or more than a predetermined range. It is also possible to detect whether the following condition is satisfied, and it is possible to accurately detect not only the presence or absence of the ink 20 but also the remaining amount thereof in an analog manner. In addition, since the position of light is detected by using the optical refraction phenomenon, it is hardly affected by the color (shading) of the liquid, and the remaining amount of the liquid is accurately detected regardless of the color of the liquid. be able to.

In the configuration of FIG. 14, in order to more accurately detect the remaining amount of liquid, the light L from the light projecting unit to the light receiving unit is required.
The irradiation position may be indicated by oblique lines in FIG. The hatched area represents the light flux of the light L, and the incident direction of the light flux is adjusted such that the lower boundary of the light flux passes through the edge P on the inner bottom surface of the tank 10. In this case, it is possible to accurately detect whether or not the ink 20 in the tank 10 has completely run out.

The light receiving section 37 of the sensor 35 is divided into two PDs 57.
FIG. 22 is a block diagram showing an example of signal processing in the case of using. In this block diagram, signals from the PDs 1 and 2 are amplified by amplifiers 51 and 52, and their outputs v1 and v
2 is converted into a digital signal by the A / D converters 53 and 54, and the operation unit 56 performs, for example, the operation of (v1-v2). Of course, there are other methods for the calculation, and the output from the calculator 56 may be compared with a reference value to be binarized (digitized).

By the processing of the light receiving signal as shown in FIG. 22, the relationship between the remaining amount of the liquid (ink 20) in the tank 10 and the output change is as shown in FIG. In FIG. 23, a solid line indicates an output change obtained by the above signal processing using the two-divided PD for the light receiving unit, and a broken line indicates an output change obtained by using the PD for the light receiving unit. According to this, even if the liquid remaining amount range in which the output change can be obtained is the same, the output change (change width c) indicated by the solid line is larger than the output change (change width d) indicated by the broken line, and the ink remaining amount can be further improved. It turns out that it can be detected.

When the apparatus having the configuration shown in FIG. 14 is applied to an ink jet printer or the like, the configuration is as shown in FIG. Again, tank 1 containing four different color inks
4, the ink cartridge 12 is constituted. The ink cartridge 12 is mounted on the print head side and is integrally movable in the direction of the arrow. The sensor 35 is installed on the printer body side, irradiates light obliquely from one side surface of each of the tanks 1 to 4 to a horizontal surface (ink liquid surface), and receives the transmitted light. I have.

In this case, the presence or absence and the remaining amount of each ink in a plurality (four) of the tanks 1 to 4 can be detected by one sensor 35 by the movement of the ink cartridge 12. In addition, since the optical refraction phenomenon is used, it is hardly affected by the color (shade) of the ink.
The presence / absence and remaining amount of ink can be accurately detected.

A specific example of the printer head is shown in FIG.
Shown in In this printer head, the ink holder 1
Reference numeral 5 denotes a recording head 16 which is movable in the direction of the arrow along the scanning rail 17. The ink holder 15 accommodates the ink cartridge 12 composed of four tanks. For each tank of the ink cartridge 12,
Through holes 15a and 15b are formed on the back and bottom of the ink holder 15, respectively. Through holes 15a, 15
As shown in FIG. 25 (b), b is obliquely penetrated through the wall and is positioned so that the light projecting portion and the light receiving portion face each other through the through holes 15a and 15b. For example, light from the light projecting portion passes through the through hole 15a, obliquely passes through the corner of the tank, passes through the through hole 15b, and enters the light receiving portion.
Of course, light may be irradiated from the through hole 15b toward the through hole 15a.

FIG. 26 shows the ink holder 18 of another printer head. The ink holder 18 accommodates two tanks, and has openings 18 at the front and the bottom.
a and 18b. By using the openings 18a and 18b, the light from the light projecting unit can be irradiated to the tank, and the transmitted light can be received by the light receiving unit. In this case, the opening 18
The light can be applied to the corners of the tank as shown in FIG. 1 by using the holes a and 18b, and from the one side of the tank to the other as shown in FIG. The light can be irradiated toward the side surface of.

When the light is applied to the corner of the tank, as shown in FIG. 27, the distance y between the light projecting part 31 and the bottom surface of the tank 10 and the distance x between the light receiving part 32 and the side surface of the tank 10 are determined. By changing the length, the detection range of the remaining amount of the liquid can be changed. However, the distances x and y may be equal (when the incident angle to the tank 10 is 45 °) or different (when the incident angle to the tank 10 is not 45 °). In addition, by using infrared region light for projection,
The effect of the transmission attenuation due to the color of the ink can be suppressed. That is, the change in the output of the infrared light with respect to the remaining amount of ink in all of the yellow ink, the red ink, the blue ink, and the black ink is larger than that of the red light, for example.

Further, when irradiating light from one side of the tank to the other side, it is important to appropriately set the incident angle θ as shown in FIG. In FIG. 28A, when light is applied obliquely from the lower side to the upper side of the tank 10, a horizontal plane (the liquid level of the ink 20)
It is necessary to increase the incident angle θ between the light and the light. Specifically, the incident angle θ is preferably about 65 ° or more (and smaller than 90 °), although it depends on the refractive index of the ink 20 and the tank 10. In FIG. 28B, when light is radiated obliquely from the upper side to the lower side of the tank 10, it is necessary to make the incident angle θ between the liquid surface of the ink 20 and the light projection shallower. Specifically, the incident angle θ is preferably about 25 ° or less (and greater than 0 °), although it depends on the refractive index of the ink 20 and the tank 10.

In each of the above embodiments, as described above, the positions of the light projecting unit and the light receiving unit may be reversed.
That is, in either case of irradiating the light obliquely to the corner of the tank or irradiating the light obliquely from one side of the tank to the other side, the light emitting part is on the upper side and the light receiving part is on the lower side. Placed on the side, the light may be directed downward, or conversely, the light projecting part is placed on the lower side, and the light receiving part is placed on the upper side,
Light may be emitted upward.

[0052]

As described above, according to the apparatus of the first aspect, the light from the light projecting portion is obliquely applied to the corner portion at the bottom of the container, and transmitted through the inside of the container and incident on the light receiving portion. Since the remaining amount of the liquid in the container is measured based on the increase or decrease in the amount of light, the device according to claim 2 irradiates the container with light from the light projecting portion obliquely with respect to the horizontal plane. Since the remaining amount of the liquid in the container is measured based on the vertical change of the optical axis of the transmitted light that passes through the inside and enters the light receiving unit, the remaining amount of the liquid can be detected in a wide range in an analog manner, Thereby, the presence / absence and remaining amount of the liquid can be accurately detected.

According to the third aspect of the present invention, even if the initial state changes (even if the distance between the container and the sensor fluctuates, the light intensity of the sensor decreases, and the light emitting surface and light receiving surface of the sensor become dirty). ,
The presence / absence and remaining amount of the liquid in the container can be detected more accurately. According to the device of the fourth aspect, since the droplet and the liquid can be accurately distinguished, the presence or absence of the liquid can be detected more accurately.

According to the apparatus of the fifth aspect, the reflection type sensor is combined with the reference container having liquid and the reference container having no liquid,
Since the presence / absence of liquid in the container is determined using the sensor outputs obtained from the reference container with liquid and the reference container without liquid as relative outputs, the presence / absence of liquid can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a basic concept of an apparatus according to an embodiment.

FIG. 2 is a perspective view of a tank in the configuration of the basic concept of FIG.

FIG. 3 is a schematic configuration diagram when the apparatus of the embodiment is applied to an ink jet printer.

FIG. 4 is a diagram showing a relationship between the remaining amount of ink obtained by the configuration of FIG. 1 and the configuration of FIG.

FIG. 5 is a diagram illustrating a detection operation of the apparatus according to the embodiment, and is a partially enlarged cross-sectional view illustrating a state where ink is sufficiently filled in a tank.

FIG. 6 is a diagram illustrating a detection operation of the apparatus of the embodiment, and is a partially enlarged cross-sectional view illustrating a state where the amount of ink in the tank is small.

FIG. 7 is a diagram illustrating a detection operation of the apparatus of the embodiment, and is a partially enlarged cross-sectional view in a state where ink is not present in a tank.

8 is a diagram showing a detection concept in the apparatus having the configuration shown in FIG. 1; FIG. 8A is a partial cross-sectional view showing a state in which a tank is sufficiently filled with ink; FIG. (B), Partial sectional view without ink in the tank (c)
It is.

FIG. 9 is a diagram showing a schematic configuration of an apparatus according to another embodiment.

FIG. 10 is a diagram showing a schematic configuration of another apparatus according to another embodiment.

11 is a diagram illustrating a detection operation when the initial state does not change in the apparatus of FIG. 9 or FIG.

FIG. 12 is a diagram illustrating a detection operation when the initial state changes in the apparatus of FIG. 9 or FIG.

FIG. 13 is a flowchart illustrating a detection operation for distinguishing an ink droplet from ink in the apparatus having the configuration of FIG. 1;

FIG. 14 is a schematic configuration diagram illustrating a basic concept of an apparatus according to still another embodiment.

15 is a block diagram illustrating an example of signal processing when a PSD is used for a light receiving unit in the device having the configuration illustrated in FIG. 14;

FIG. 16 is a diagram showing a relationship between a liquid remaining amount obtained by the signal processing of FIG. 15 and an output change.

FIG. 17 is a diagram illustrating a detection operation of the apparatus of the embodiment, and is a partially enlarged cross-sectional view illustrating a state where ink is sufficiently filled in a tank.

FIG. 18 is a diagram illustrating a detection operation of the apparatus of the embodiment, and is a partially enlarged cross-sectional view in a state where the amount of ink in the tank is small.

FIG. 19 is a diagram illustrating a detection operation of the apparatus according to the same embodiment, and is a partially enlarged cross-sectional view illustrating a state in which the amount of ink remaining in the tank is small.

FIG. 20 is a diagram illustrating a detection operation of the apparatus according to the same embodiment, and is a partially enlarged cross-sectional view illustrating a state where ink remains in the tank even less.

21 is a view showing a detection concept in the apparatus having the configuration shown in FIG. 14, and is a partial cross-sectional view showing a state where the ink is sufficiently filled in the tank, and a partial cross-sectional view showing a state where the ink in the tank is small. FIG. 4B is a partial cross-sectional view of the state where the ink remains in the tank.

FIG. 22 is a block diagram illustrating an example of signal processing when a two-divided PD is used for a light receiving unit in the device having the configuration illustrated in FIG. 14;

FIG. 23 is a diagram showing a relationship between a remaining liquid amount obtained by the signal processing of FIG. 22 and an output change.

FIG. 24 is a diagram showing a schematic configuration when a plurality of tanks are detected by one sensor.

25A is a perspective view showing an example of a printer head embodying the configuration of FIG. 24, and FIG. 25B is a partially enlarged sectional view showing a through hole of an ink holder.

FIG. 26 is a perspective view showing another example of a printer head that embodies the configuration of FIG. 24;

FIG. 27 is a diagram illustrating positions of a light projecting unit and a light receiving unit when light is radiated obliquely to a corner of a tank.

FIG. 28 (a) is a view showing the incident angle of light when obliquely irradiating light upward from one side surface of the tank to the other side surface, and shows light from one side surface of the tank to the other side surface. FIG. 7B is a diagram (b) illustrating an incident angle of light projection when the light is emitted obliquely downward.

FIG. 29 is a diagram showing a basic configuration of an apparatus according to a conventional example.

FIG. 30A is a diagram showing a basic configuration of another device according to the conventional example, and FIG. 30B is a diagram showing a sensor structure of the device.

FIG. 31 is a diagram showing a schematic configuration of still another device according to the conventional example.

FIG. 32 is a diagram for explaining the detection operation of the device of FIG. 31.

FIG. 33 is a flowchart illustrating a detection operation of the device having the configuration of FIG. 30;

[Explanation of symbols]

 5 Reference Tank Without Ink 6 Reference Tank With Ink 10, 11 Tank (Container) 10a Corner 12 Ink Cartridge 15, 18 Ink Holder 20 Ink (Liquid) 30, 35 Sensor 31, 36 Light Projector 32, 37 Light Receiver 40 Reflective sensor L Light

Claims (5)

[Claims] 1. A light-transmissive container having a corner at a bottom for storing a liquid, and a light-transmissive container disposed at the corner of the container bottom.
A light-emitting unit and a sensor having a light-receiving unit that receives light from the light-emitting unit. The light from the light-emitting unit is obliquely applied to the corner of the bottom of the container, passes through the container, and enters the light-receiving unit. A liquid remaining amount detecting device for measuring the remaining amount of liquid in a container based on a change in the amount of transmitted light. 2. A light-transmitting container for storing a liquid, a light-emitting unit and a sensor having a light-receiving unit for receiving light from the light-emitting unit and detecting the position of a light-receiving spot, and projecting light into the container. Irradiates the light from the part obliquely to the horizontal plane, and measures the remaining amount of liquid in the container based on the vertical change of the optical axis of the transmitted light transmitted through the container and incident on the light receiving unit. Liquid remaining amount detection device. 3. In addition to the container, a container that can be used for a reference with a liquid and a container that can be used for a reference without a liquid are arranged.
3. The liquid remaining amount according to claim 1, wherein the sensor output obtained from each of the reference container having liquid and the reference container having no liquid is used as a relative output to measure the remaining amount of the liquid in the container. Detection device. 4. The liquid remaining amount detecting device according to claim 1, wherein the liquid amount and the liquid amount in the container are distinguished by an analog amount relating to a change in the amount of transmitted light incident on the light receiving unit. 5. A light-transmitting container for storing a liquid, a container that can be used as a reference with liquid, a container that can be used as a reference with no liquid, and a light projecting unit and a light receiving unit. A reflection type sensor that irradiates light from the container and receives reflected light from the container at the light receiving unit, and outputs the sensor output obtained from the reference container with liquid and the reference container without liquid as a relative output. A liquid remaining amount detecting device for determining the presence or absence of a liquid in a container.