JPH1024601A - Ink cartridge and ink end detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink cartridge and an in k end detecting device easily controllable for detecting the ink end, capable of detecting the real end of the ink without detection irregularity. SOLUTION: An ink storage 10 with a second filter member 12 having an aperture larger than that of an ink jetting nozzle 2 of a recording head 1 attached thereto is provided adjacent to an ink take-out channel 9. When the back pressure of the upper surface of the second filter member becomes lower than capillary tube force of the second filter member 12 according to the ink consumption, the meniscus of the second filter member 12 collapses so that bubbles enter the ink storage 10. A photo interrupter penetrated by an optical axis is provided in the ink storage 10, with the blocking state changeable by the entrance of the air into the ink storage 10. The change is judged by an ink end judging means to determine the ink end. Since the meniscus of the second filter member 12 is weaker than the meniscus of the ink jetting nozzle 2, the ink end judgment can be made before the ink jetting operation is disabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to an ink end detecting method for detecting the presence or absence of residual ink in an ink cartridge for supplying ink to a recording head of the ink jet recording apparatus.

[0002]

2. Description of the Related Art In order for a recording head to eject ink stably, it is necessary to supply ink from an ink cartridge to the recording head with a negative minute pressure (hereinafter referred to as "back pressure"). A method of generating this back pressure by the capillary force of an ink-impregnated member made of a porous material is useful, and many ink cartridges have been put to practical use.

Conventionally, as means for detecting the presence or absence of residual ink in an ink cartridge of an ink jet recording apparatus using such an ink impregnated member, JP-A-3-2849 has been proposed.
As disclosed in Japanese Patent No. 53, two metal electrodes are inserted inside the ink cartridge, and the measured resistance value between the electrodes is referred to a storage table indicating the relationship between the remaining amount of ink and the resistance value in advance. By doing so, a method of determining the presence or absence of ink is considered useful.

[0004] As shown in JP-A-4-00715,
The total number of ink ejection pulses of the recording head is counted, the used ink amount is calculated from the previously stored ink ejection dot mass and the total number of ink ejection pulses, the remaining ink amount of the ink cartridge is estimated from the calculation result, and the ink amount is calculated. A method for determining the end is disclosed.

[0005]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 3-28495
In the conventional example disclosed in No. 3, since the relationship between the resistance and the remaining amount of ink greatly changes depending on the printing duty and the manufacturing process, it is necessary to use the ink to reliably determine the ink end before missing dots occur. The detection means must be set so that the ink is exhausted while a large amount of ink remains in the cartridge, and there is a problem that expensive ink is wasted.

In addition, it is necessary to change the threshold value of the ink end resistance depending on the environmental temperature.
A recording device must be equipped with means capable of continuously detecting the level of an A / D converter or the like, which causes a problem that the device becomes complicated.

Further, in the ink resistance detection method, a voltage is applied to the ink at the time of resistance measurement. Therefore, in an ink jet recording apparatus using a recording head having a structure in which a drive circuit is in contact with the ink, the head drive circuit and the ink end detection Since it has a serious problem that a short circuit occurs, it cannot be adopted.

Japanese Patent Laid-Open No. 4-007158, which calculates the amount of used ink from the number of ink ejection pulses and the unit of ink ejection,
A counting means for counting the number of ink ejection pulses, a storage means for storing the number of ink ejection pulses when the power of the recording apparatus is turned off, and a storage means for storing the mass of ink ejection dots inputted in advance; This is achieved by estimating the consumed ink from the ejection dot mass. However, since the ink ejection dot mass varies between the environmental temperature and the individual print heads, the ink end error can be reduced as in the first conventional example. In order to stop printing at the end of the ink and to surely stop printing, it is necessary to end the ink when the remaining amount of the ink is large, which increases the amount of ink that cannot be used effectively and shortens the ink life of the ink cartridge. Have issues. Further, since the main control means of the printing apparatus and the means for counting the number of ink ejection pulses are common, it is necessary to count the number of ink ejection pulses while controlling the printing apparatus, so that control means capable of high-speed operation is required. However, a memory with a backup power supply or a flash memory for storing and holding the number of ink ejection pulses when the power is turned off is required, which has a problem that the control device becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an ink cartridge and an ink end detection method capable of easily detecting the ink end, detecting the true ink end, and having no variation in the detection. It is intended to provide a device.

[0010]

According to the present invention, there is provided an ink cartridge as an ink cartridge for solving the above-mentioned problem, wherein an ink communicating with the recording head is provided at a lower end of an ink tank loaded with an ink impregnating member made of a porous member impregnated with ink. A take-out channel, an ink reservoir juxtaposed with the ink take-out channel, for externally determining the presence or absence of ink, a first filter member between the ink take-out channel and the ink impregnated member, A second filter member is provided between the reservoir and the ink impregnating member, and the capillary force generated by the surface tension of the ink causes the ink impregnating member, the second filter member, the ink jet nozzle of the recording head, It is characterized in that the hole diameter is such that it increases in the order of the first filter member.

According to the above configuration of the present invention, immediately before the ink end, the ink is lost in the order of the ink impregnating member and the second filter member, and at the moment when the meniscus formed in the hole of the second filter member is broken, The ink in the ink reservoir runs out. Since the photointerrupter is released from the state of being blocked by the ink, the output changes. This output change is determined by the detection means, and the ink end is detected. Since the ink jet nozzle of the recording head has a larger capillary force than the second filter member, air bubbles are not taken in from the ink jet nozzle before the ink end. Further, since the first filter member has a larger capillary force than the second filter member,
Air bubbles do not flow out of the ink cartridge to the recording head.

[0012] Further, the ink outlet channel and the opening of the ink reservoir are juxtaposed to protrude from the ink tank so as to partially compress the ink impregnated member. Increase the power,
The ink easily collects in the ink extraction channel and the ink reservoir, and the remaining amount of ink at the time of ink end decreases.

[0013] Further, the first filter member and the second filter member are formed of porous members having a thickness for partially compressing the ink impregnated member, thereby reducing the remaining amount of ink.

By forming a fine groove on the side wall of the ink reservoir of the ink cartridge so that the ink rises by capillary force, the ink rises in the groove of the side wall in the ink reservoir at the time of ink end, and the ink reservoir is completely emptied. Therefore, it is easy to determine whether there is ink from outside the ink tank.

Further, as an ink end detecting device using the above-mentioned ink cartridge, a transmission type photo interrupter for detecting visible light having an optical axis crossing the ink reservoir is arranged, and the output change generated by the photo interrupter is also detected. In addition, the provision of the determination means for determining the presence or absence of the ink facilitates the detection of the ink end.

Further, by disposing an optical filter on the optical axis of the photointerrupter for blocking infrared light, the sensitivity of the photointerrupter in the infrared wavelength region is eliminated, and the infrared wavelength of the ink is made transparent. Cancel the characteristic.
Therefore, the output ratio of the photo interrupter in the presence or absence of ink becomes large, so that the end of ink can be easily determined.

[0017]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of the ink cartridge and the ink end detecting means of the present invention, and shows a state where the ink cartridge and the ink end detecting unit are mounted on a carriage unit of an ink jet recording apparatus. FIG. 2 is a side sectional view of a carriage section of an ink jet recording apparatus equipped with the ink cartridge and the ink end detecting means of the present embodiment.
3, 4, 5, 6, and 7 are explanatory diagrams of the operation of the present embodiment. FIG. 8 is a partial detailed view of the present embodiment. FIG. 9 is a side sectional view showing another embodiment.
FIG. 10 is an overall perspective view of another embodiment.

The configuration will be described with reference to FIGS. In FIG. 1, a recording head 1 for ejecting ink includes a pressure chamber (not shown) to which an electromechanical transducer is joined, an ink ejection nozzle 2, and an ink introduction path 3 to the pressure chamber. I have. In the figure, reference numeral 4 denotes an ink cartridge, which includes an ink tank 5, an ink impregnated member 6, a lid member 7, and a packing member 8 connected to the ink introduction path 3 of the recording head 1 loaded in the ink tank 5. It is configured. At the bottom surface of the ink tank 5, an ink reservoir having a protruding tubular ink extraction channel 9 and a protrusion having the same height as the ink extraction channel 9 and having an open end juxtaposed with the ink extraction channel 9. 10 are integrally formed. 1 in the figure
Reference numeral 1 denotes a first filter member fused to the entire opening end of the ink take-out channel 9;
Is a second filter member fused to the open end of the second filter member. A packing member 8 is inserted into the other end of the ink outlet channel 9. The other end of the ink reservoir 10 is closed. In the drawing, reference numeral 13 denotes a transport unit on which the recording head 1 and the ink cartridge 4 are mounted. In the figure, reference numeral 14 denotes a photo interrupter having an optical axis extending through the ink reservoir 10. Reference numeral 15 denotes an optical filter for cutting the infrared wavelength region of the photo interrupter 14, which is fixed to the photo interrupter 14. The output of the photo interrupter 14 is provided in the control block of the recording apparatus main body via the flexible substrate 16.
It is connected to the ink end determining means 17.

In the drawing, reference numeral 18 denotes an aqueous ink using a dye as a coloring agent, which is held in the pores of the ink impregnated member 6.

Next, the structure of each part will be described in more detail.

The ink ejecting nozzle 2 of the recording head 1 is about 3
It has a circular shape of 0 microns. The ink jet nozzle 2 uses a single crystal silicon plate as a material, and a thermal oxide film is formed on the inner surface of the nozzle hole to improve the wettability with the ink 18. However, the surface of the nozzle hole is subjected to an ink-repellent treatment so that the ink 18 can be smoothly ejected. The contact angle between the ink 18 and the thermal oxide film is 0 to 15 degrees, and the capillary force generated between the ink jet nozzle 2 and the ink 18 is about 3000 Pascal. Therefore, it is necessary to supply the ink to the recording head 1 at a pressure not exceeding -3000 Pascal. The ink introduction part 3 is a tubular flow path,
The tip is removably inserted into the packing member 8 of the ink cartridge 4. The material of the ink tank 5 of the ink cartridge 4 is a material having a high ink resistance and a small change in the physical properties of the ink, and is made of transparent or milky polypropylene that transmits visible light. The ink take-out channel 9 formed on the bottom surface of the ink tank 5 has a projecting height of about 8 millimeters, an open end having a large area, and the first filter member 11 being thermally fused. The ink take-out channel 9 gradually decreases in cross-sectional area toward the lower end, has a circular end at the end, and has a circular packing member 8 fitted therein.

The first filter member 11 has an opening diameter of 3-5.
It is a stainless steel wire net of micron meter, has an opening size smaller than the hole size of the ink jet nozzle 2 of the recording head 1, and generates a capillary force of about 9000 Pascal with the surface tension of the ink 18. Therefore, it is sufficiently larger than the capillary force generated by the ink jet nozzle 2.

The replenishment of the ink 18 into the recording head 1 immediately after the ink ejection is performed by the capillary force of the ink ejection nozzle 2. Since the capillary force of the first filter member is stronger than the capillary force of the ink jet nozzle 2, air bubbles do not pass through the first filter member 11 in printing. In addition, it is possible to completely prevent foreign substances that clog the ink jet nozzle 2 from flowing out of the ink cartridge 4.

As described above, the ink reservoir 10 is a protrusion having the same height as the ink outlet channel 9 and has an open end juxtaposed with the ink outlet channel 9. The ink reservoir 10 has a thickness of about 1.5 mm on the optical axis of the photo-interrupter 14 and is closed at the other end. The thickness of the wall of the ink reservoir 10 on the optical axis of the photointerrupter 14 is 0.5 mm, so that light can pass through even a milky white material. The inner surface of the ink reservoir 10 excluding the optical axis of the photo interrupter 14 has a width of 0.2 mm or less,
1 is provided, and the ink 18 can hang down this groove by surface tension. (The replacement of air bubbles and ink can be performed smoothly at the moment of the ink end described later.)
At the opening end of the ink reservoir 10, a second filter member 12 having an opening diameter slightly larger than that of the ink jet nozzle 2 of the recording head 1 is fused. More specifically, 50-7
A nylon mesh having an opening diameter of 0 micrometer was used. The capillary force generated by the second filter member 12 and the ink 18 is about 1200 to 2000 Pascal. Therefore, the meniscus of the second filter member 12 can be broken before the recording head 1 becomes unable to eject ink due to the capillary force weaker than the capillary force of the ink ejection nozzle 2.

The ink impregnated member 6 is made of an ether-based polyurethane foam.
It has a large number of holes having an opening diameter of 30 to 200 microns. The bottom surface of the ink impregnating member 6 partially creates a highly compressed state by the projecting height of the ink take-out channel 9 and the ink reservoir 10 via the first filter 11 and the second filter 12. Due to this compression, the first filter member 11 and the second filter member 12 are in close contact with the ink impregnated member 6. Ink impregnating member 6 at this site
Is about 100 μm, which is slightly larger than the opening diameter of the second filter member 12. The capillary force generated by the ink impregnating member and the ink 18 is 300 to 1000.
Pascal.

The capillary force of each part is determined by the first filter 11>
Ink jet nozzle 2> second filter member 12> ink impregnated member 6. FIG. 7 shows the absorbance of the ink (also in the strongest order of meniscus). The ink 18 using a dye as a colorant transmits infrared light of about 700 nanometers or more without absorbing it. Therefore, since it is impossible to detect the presence or absence of the ink 18 with a photointerrupter using an infrared light emitting diode which is generally widely used, in this embodiment, a red or blue light emitting diode is provided on a light emitting side, and a photodiode or a photo diode is used. A photointerrupter 14 having a transistor on the light receiving side was used. Even a photointerrupter having a main emission wavelength in the visible light region has sensitivity up to the infrared region centered at about 700 nanometers as shown in FIG. However, the output signal ratio when ink is present is reduced. Therefore, in order to increase the signal output ratio depending on the presence or absence of ink, an infrared cut optical filter shown in FIG. 15 was set on the optical axis of the photointerrupter 14 to cut the infrared wavelength region. The optical filter 15 was formed by adding an infrared absorbent to an acrylic resin and performing injection molding. The optical filter 15 is shown in FIG.
The optical filter 1 shows the light absorption characteristic shown in FIG. Next, the operation will be described. FIG. 3 is a diagram showing an initial state of the ink cartridge 4 and showing a state in which a large amount of ink 18 remains inside. FIG. 4 is a diagram showing a state in which consumption of the ink 18 progresses and bubbles 19 are collected on the upper surfaces of the first filter member 11 and the second filter member 12. FIG. 5 is a diagram showing a state in which the meniscus of the second filter member 12 is broken and air 20 has entered the ink reservoir 10. FIG. 6 is a graph showing the ink pressure of each part. The horizontal axis indicates the consumption of the ink 18 and the vertical axis indicates the pressure.

In FIG. 6, A indicates the ink pressure inside the recording head 1. B is the capillary force of the second filter member 12 (= meniscus strength, hereinafter omitted), C is the capillary force of the ink jet nozzle 2, and D is the upper surface of the first filter member 11 and the second filter member 12. The pressure in the ink impregnation member 6 and the ink reservoir 10 is shown.

At the start of use of the ink cartridge 4, FIG.
As shown in the figure, the ink 18 in the ink impregnated member 6 forms a meniscus on the outer peripheral portion of the ink impregnated member 6, and the inside is almost filled with the ink 18. The back pressure generated in the first filter member 11 and the second filter member 12 is generated by the pore diameter of the outer peripheral portion of the ink impregnated member 6 having a size of about -300 Pascal. A back pressure of about -200 Pascal is applied to the recording head 1 whose installation position is lower than the above. There are no bubbles near the first filter member 11 and the second filter member 12. The ink reservoir 10 is filled with ink,
The photo interrupter 14 is in a shielding state.

When the recording head 1 sucks the ink 18 to eject ink, the ink 18 in the ink impregnating member 6 flows to the recording head 1 via the first filter member 11 and the ink take-out channel 9. Air enters the portion of the ink impregnated member 6 where the ink 18 has been consumed. The ink 18 flows from a portion of the ink impregnated member 6 having a large hole diameter, and the meniscus gradually moves to a portion having a small hole diameter. Accordingly, the capillary force increases, and the back pressure on the upper surfaces of the first filter member 11 and the second filter member 12 and inside the recording head 1 gradually decreases as shown in FIG. Although there is no flow of the ink 18 in the ink reservoir 10, the ink reservoir 10 is arranged in parallel with the ink extraction flow path 9 at substantially the same height and in the vicinity thereof. 18 occurs, and the second filter is formed similarly to the upper surface of the first filter member 11.
Bubbles 19 also collect on the upper surface of the filter member 12. Further, the consumption of the ink 18 proceeds, and in a state where the substantially entire surface of the second filter member 12 is
When the air is sucked, the pressure of the air bubble 19 is changed to the second filter member 1.
When the capillary force exceeds 2 (about 1200 Pascal), the meniscus is broken as shown in FIG. The ink 18 in the ink reservoir 10 is absorbed by the ink impregnating member 6 by the capillary force of the ink impregnating member 6. Since the ink reservoir 10 is provided on the bottom surface of the ink tank 5, it is difficult to move.
As shown in FIG. 7, a fine groove 21 is provided on the inner wall surface, and this groove is hung by the surface tension of the ink 18, so that all of the groove is absorbed by the ink impregnated member 6. Therefore, the ink pool 10
Becomes empty and is closed with air 20. In FIG. 6, the pressure of the ink 18 on the upper surface of the second filter member 12 rapidly changes to zero. Note that a porous member may be inserted instead of the groove 21.

Since the transmission state of the ink reservoir 10 has changed, the output signal of the photointerrupter 14 changes, and the ink end determining means 17 determines that the ink is out. Based on the result of this determination, the recording apparatus in which the apparatus is mounted is set to the ink end state, printing cannot be continued, and the apparatus is stopped. In this state, the pressure (-1200 Pascals) of the ink in the recording head 1 is much weaker than the capillary force (the meniscus strength of 2500 Pascals, C in the figure) of the ink ejecting nozzle 2 as shown in FIG. 2
The ink end can be detected and printing can be stopped without destroying the meniscus.

Further, since the meniscus strength of the first filter member 11 is larger than that of the second filter member 12, bubbles do not flow out of the ink cartridge 4 to the recording head 1 before the ink end.

FIG. 9 shows that the first filter member 40 and the second filter member 42 are made of high-density felt or open-cell foam, and the ink outlet channel 42 and the ink reservoir 43 project into the ink tank 44. An embodiment is shown in which the ink impregnated member 45 is compressed by a filter member, but the same effect as in the previous embodiment can be obtained.

In this embodiment, the transmission type photointerrupter 14 having a straight optical axis is used. Next, a second embodiment in which the optical axis is formed by a prism will be described.

In FIG. 10, reference numeral 30 denotes a prism provided on the ink cartridge 31, and a prism
2 on both sides. Prism is visible light emitting element 3
3, a first incident portion 34, a first optical axis converting portion 35, a first output portion 36 to the ink reservoir 32, and a second incident portion 37 from the ink reservoir 32 and a second And a second output unit 40 to the visible light receiving element 39. The prism 30 is made of acryl to which an infrared absorbing agent is added, and is integrally formed by injection molding. As the visible light emitting element 33, a red diode or a lamp can be used. As the visible light receiving element 39, a photodiode or a phototransistor can be used. According to the present embodiment, the visible light emitting element 33 and the visible light receiving element 39 can be arranged in a plane, so that the height of the ink end detecting means can be suppressed and a thin recording device can be configured. Become.

[0035]

According to the present invention, the ink end state of the ink cartridge is changed in the detecting portion by the back pressure of the ink, so that the ink end can be set at the ink ejection limit of the recording head. Therefore, there is no need to consider detection variations. In addition, since the optical-electrical conversion element is used, signal processing of the detection means can be performed relatively easily. In addition, it is a non-contact detection, and has an effect that the ink ejection performance of the recording head is not affected at all. Furthermore, since the detection time is short and there is no limitation on the number of times of detection such as the ink resistance by the electrodes, the detection can be always performed when the printing apparatus is used, and the detection error can be prevented. In addition, there is the effect that it is hardly influenced by the ink ejection duty of the recording head and the environmental temperature, and auxiliary detection for detection and calculation in the control circuit become unnecessary. In addition, the use of the prism has an effect that the height of the ink end detecting means can be suppressed and a thin recording apparatus can be configured.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view of one embodiment of the present invention.

FIG. 3 is an explanatory diagram of the operation of the embodiment of the present invention.

FIG. 4 is an explanatory diagram of the operation of the embodiment of the present invention.

FIG. 5 is an explanatory diagram of the operation of the embodiment of the present invention.

FIG. 6 is an explanatory diagram of a pressure change in each operation of the embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating a difference in absorbance depending on the irradiation wavelength of the ink according to the embodiment of the present invention.

FIG. 8 is a diagram showing details of a part of the embodiment of the present invention.

FIG. 9 is a side sectional view showing another embodiment of the present invention.

FIG. 10 is an overall perspective view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Ink ejection nozzle 3 Ink introduction path 4 Ink cartridge 5 Ink tank 6 Ink impregnating member 7 Lid member 8 Packing member 9 Ink extraction channel 10 Ink pool 11 First filter member 12 Second filter member 13 Transport means Reference Signs List 14 photo interrupter 15 optical filter 16 flexible substrate 17 ink end determining means 18 ink 19 bubble 20 air 31 prism 33 visible light emitting element 39 visible light receiving element

Claims (6)

[Claims] 1. An ink take-out flow path communicating with a recording head at a lower end of an ink tank loaded with an ink impregnated member made of a porous material impregnated with ink. Providing a first filter member between the ink taking-out channel and the ink impregnating member, and a second filter member between the ink reservoir and the ink impregnating member. The hole diameter is such that the capillary force generated by the surface tension becomes larger in the order of the ink impregnating member, the second filter member, the ink jet nozzle of the recording head, and the first filter member. ink cartridge. 2. The ink cartridge according to claim 1, wherein the ink take-out passage and the opening of the ink reservoir protrude from the ink tank so as to partially strongly compress the ink impregnated member. An ink cartridge characterized by being juxtaposed. 3. The ink cartridge according to claim 1, wherein the first filter member and the second filter member are formed of a porous member having a thickness that partially compresses the ink impregnated member. An ink cartridge characterized in that: 4. The ink cartridge according to claim 1, wherein a fine groove is formed on a side wall of the ink reservoir, where the ink rises by a capillary force. 5. An ink cartridge according to claim 1, further comprising a transmission type photo interrupter for detecting visible light having an optical axis crossing said ink reservoir, wherein an output change generated by said photo interrupter is also detected. And an ink end detecting device for determining whether or not there is ink. 6. The ink end detecting device according to claim 5, wherein an optical filter for blocking infrared wavelength light is provided on the optical axis of the photo interrupter.