JP2000015836A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inform a user to exchange filters by removing a foreign matter in an ink discharged to an ink passage and detecting a clog. SOLUTION: A sensor 14 of a pair of electrodes is set in an ink passage between a filter 12 of an ink-jet recording head 1 and a sub ink tank 4. The sensor 14 judges the presence/absence of a clog of the filter 12. If the filter 12 does not clog, a sub pump 8 is rotated and then a easing is filled with the ink, whereby the pair of electrodes are shortcircuited, and it is so detected that the ink is present. On the other hand, if the filter 12 clogs, the casing is not filled with the ink even a predetermined time after the sub pump 8 is rotated, and the pair of electrodes are held in a disconnection state to avoid the detection that the ink is present.

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 for recording on a recording medium by discharging ink, and more particularly to an ink jet recording apparatus having a long ink jet recording head having more than 1,000 nozzles. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, as this kind of ink jet recording apparatus, an ink jet recording apparatus having an ink supply device having an ink circulating means is known. Such an ink jet recording apparatus is, as shown in FIG. Ink jet recording head 101 and ink cartridge 1
02, a main pump 103, a sub pump 104,
It has an ink flow path formed by the filter 105 and the one-way valve 106, and the air buffer tank 115 and the sub ink tank 116.

[0003] Such an ink flow path includes a main pump 103, which is a first pressure pump for supplying ink from the ink cartridge 102 to the ink jet recording head 101 via a sub ink tank 116, and an ink of a recovery device. The sub-pump 10 serving as a second pressure pump for returning ink from the receiver 111 to the sub-ink tank 116
And 4. In the ink flow path for circulating such ink, a filter 105 is provided in the ink flow path on the downstream side of the inkjet recording head 101 for the purpose of removing dust in the ink.

In the ink flow path shown in FIG.
When supplying ink, the valves 112, 113, and 117 are closed, and the main pump 103 is rotated counterclockwise so that the ink in the ink cartridge 102 passes through the one-way valve 109 and passes through the air buffer tank 115. Is stored in the sub ink tank 116. When the ink accumulates above a certain level, the excess ink is stored in the tube 118.
The ink is returned to the ink cartridge 102 through the sub ink tank 116 so that the amount of ink in the sub ink tank 116 becomes full.

[0005] Such an ink jet recording head 10
In No. 1, a recovery device (not shown) performs a recovery operation on the inkjet recording head 101 so that the inkjet recording head 101 can perform printing stably. In this recovery operation, the ink supply device having the above-described configuration circulates ink with respect to the ink jet recording head 101, and thereby, the nozzles of the ink jet recording head 101 can always be kept in a printable state. ing.

Therefore, when performing the recovery operation, the valve 11
2, 113 and 117, and by rotating the main pump 103 clockwise, the sub ink tank 11 is opened.
6 passes through a valve 112 which is open via an air buffer tank 115, and the ink jet recording head 1
01 is sent. At this time, the ink discharged from the nozzle of the ink jet recording head 101
1 and is returned by the sub-pump 104 to the sub-ink tank 116 through the one-way valve 106 and the filter 105.

At the time of printing, the valves 112, 11
3, 117 are opened, and the ink jet recording head 101 is opened.
The ink is refilled only through the open valve 113 and through the open valve 112, the air buffer tank 115, and the main pump 103, only by the discharge force that is discharged.

[0008]

However, in the ink flow path of such an ink jet recording apparatus,
When the filter 105 between the ink jet recording head 101 and the ink supply device is clogged with dust or the like,
Add sub-pump 104 to clogged filter 105
In some cases, the flow resistance of the ink becomes very high because of the ink feeding. If the recovery operation is performed in such a state where the flow resistance of the ink is high, the circulation of the ink may not be performed smoothly, or the pressure in the ink flow path between the inkjet recording head 101 and the ink supply device may be reduced. It becomes very large, and the joint portion of the tube connecting the ink jet recording head 101 and the ink supply device cannot withstand the pressure and comes out, and the ink scatters into the ink jet recording device, and the inside of the ink jet recording device becomes dirty. Inconveniences such as inconvenience occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an ink jet recording apparatus which detects clogging of a filter and informs a user of replacement of the filter. Is to do.

[0010]

Accordingly, in order to achieve the above object, an ink jet recording apparatus according to the present invention has an ink jet recording head having an ink jet recording head for performing recording by discharging ink, and an ink circulating apparatus. The apparatus is characterized in that it has means for removing foreign matter in the ink discharged to the ink flow path, and means for detecting clogging of the means.

Further, the ink jet recording apparatus of the present invention is characterized in that the means for removing the foreign matter has a filter, the detecting means has a sensor, and the sensor is arranged downstream of the filter. .

Further, in the ink jet recording apparatus of the present invention, the sensor has at least a pair of electrodes.

Further, in the ink jet recording apparatus according to the present invention, the sensor has a transmission type photo interrupter.

In the ink jet recording apparatus of the present invention, the ink circulation device has a main pump and a sub pump.
The sub-pump is arranged on the upstream side, the filter is arranged on the upstream side of the sub-pump, and the sensor is arranged on the downstream side of the sub-pump.

In addition, the ink jet recording apparatus of the present invention comprises: an ink jet recording head; an ink receiver for receiving ink ejected from the ink jet recording head;
An ink tank holding ink, a main pump for supplying ink from the ink tank to the ink jet recording head, and a sub-pump provided in an ink flow path between the ink receiver and the ink tank; Collecting the ink ejected from the ink jet recording head by the ink receiver, returning the ink to the ink tank for reuse, and providing the filter and the sensor in an ink flow path from the ink receiver to the ink tank. It is characterized by.

Further, the ink jet recording apparatus of the present invention is characterized in that the filter is judged to be clogged when the sensor does not detect the presence of ink even after a certain time has elapsed after the rotation of the sub-pump. I do.

Further, the ink jet recording apparatus of the present invention is characterized in that it has a pressure sensor for detecting a change in the ink flow as a change in pressure.

An ink jet recording apparatus according to the present invention is characterized in that the ink tank has a sub tank and an air buffer tank.

Further, an ink jet recording apparatus of the present invention is characterized in that an ink cartridge is connected to the ink tank.

[0020]

As described above, according to the ink jet recording apparatus of the present invention, a change in the ink flow in the ink flow path is detected by the detection means, and the ink circulation means is operated in accordance with the change in the ink flow. Since it has control means to stop,
An inexpensive sensor is added as a detecting means, and a filter as a foreign matter removing means is located just upstream of the pump device, so that clogging of the filter is suitably detected, and a user is warned of replacing the filter. The filter can be processed simply and quickly and replaced, etc.

Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

(Embodiment 1) FIG. 1 is a circuit diagram showing a first embodiment of an ink jet recording apparatus that best illustrates the present invention. FIGS. 2 and 3 are first embodiment of an ink jet recording apparatus of the present invention. FIG. 3 is a detailed explanatory diagram of an ink circulation system sensor used in the embodiment.

The ink jet recording apparatus according to the present invention is shown in FIG.
As shown in FIG. 1, an ink jet recording head 1 for discharging ink, an ink receiver 2 for receiving ink discharged from the ink jet recording head 1, an ink tank 3 including a sub ink tank 4 and an air buffer tank 5 for holding ink. And a pump device including an ink cartridge 6 connected to the ink tank 3, a main pump 7 for pressurizing and supplying a sub-pump 8 for circulating and supplying ink, and an ink jet recording head 1, an ink receiver 2, and an ink tank 3 Tubes 9, 10, 11 for connecting the ink cartridge 6, the pump device, etc.
And an ink flow path formed by a filter 12 and a sensor 14 provided between the ink receiver 2 and the sub ink tank 4.

The ink receiver 2 can also serve as a cap member that covers the ink ejection surface of the ink jet recording head 1 when not in use and caps the ink ejection surface, and caps the ink ejection surface of the ink jet recording head 1. As a result, the nozzles on the ink ejection surface of the ink jet recording head 1 are shut off from the external air, so that it is possible to prevent the ink from thickening or sticking inside the nozzles due to natural evaporation.

In the ink flow path of the ink jet recording apparatus of the present invention, the ink jet recording head 1
Is connected to the air buffer tank 5 of the ink tank 3 by a tube 9 provided with a valve 16, and is further connected to the ink tank 3 by a tube 10 provided with a valve 17.
Are connected to the sub-ink tank 4 of the printer.

The ink receiver 2 for receiving the ink ejected from the ink jet recording head 1 passes through a tube 20 provided with a one-way valve 13, a filter 12, a sub-pump 8 of a pump device, and a sensor 14 in order from the upstream side. Connected to the sub-ink tank 4 of the ink tank 3.

Ink cartridge 6 for storing ink
Are connected to the sub-ink tank 4 of the ink tank 3 by a tube 11, and further connected to the air buffer tank 5 of the ink tank 3 by a tube 21 provided with a one-way valve 15. Further, the sub-ink tank 4 of the ink tank 3 and the air buffer tank 5 are connected to each other by a main pump 7 which can be rotated clockwise and counterclockwise in the forward and reverse directions. One end of a pump tube 7a of the main pump 7 is connected to the sub-ink tank. The other end is connected to the air buffer tank 5. Therefore, by the operation of the main pump 7, ink is supplied from the sub ink tank 4 to the air buffer tank 5, or vice versa, from the air buffer tank 5 to the sub ink tank 4 according to the rotation direction of the main pump 7.

A tube 22 is connected to the sub-ink tank 4 of the ink tank 3.
2 is provided with a one-way valve 18 and a valve 19 so as to communicate with the atmosphere.

In such an ink flow path, each of the tubes 9, 10, 11, 20, 21, 22 and the like is made of an appropriate piping member such as a metal pipe or a plastic tube.

In the ink flow path of the ink jet recording apparatus of the present invention thus configured, the pump device supplies ink from the ink cartridge 6 and pressurizes the ink for supplying ink to the ink jet recording head 1. Main pump 7 and inkjet recording head 1
And a suction sub-pump 8 for receiving the ink ejected from the ink receiver 2, sucking the ink into the sub-ink tank 4, and collecting the ink.

Further, the main pump 7 for pressurization and the sub-pump 8 for suction of the pump device can be formed in the same tube pump structure, and as shown, the pump tubes 7a, 8a and the rotary Members 7b, 8b
Each of the rollers 7d and 8d is, in the illustrated embodiment, four rollers 7d and 8d urged by springs 7c and 8c disposed on the outer periphery of the roller. Therefore, the main pump 7 and the sub-pump 7 sequentially send and supply the ink in the pump tubes 7a, 8a by pressing the pump tubes 7a, 8a with the rollers 7d, 8d by the rotation of the rotating members 7b, 8b. It is composed.

When ink is supplied by the pressurizing main pump 7 of the pump device constructed as described above, the valve 1
6, 17 and 18 are closed and the main pump 7 is rotated counterclockwise, so that the pump tube 7a
As a result, the roller 7d moves while pressing the pump tube 7a, thereby supplying ink. That is,
The rotation of the main pump 7 causes the ink cartridge 6
The ink stored in the sub-ink tank 4 passes through the one-way valve 15 and is stored in the sub-ink tank 4 via the air buffer tank 5. When the ink is stored in the sub-ink tank 4 to a certain degree or more, the ink cartridge 6 passes through the tube 11. And the ink amount in the sub ink tank 4 becomes full.

Therefore, as shown in FIG. 1, the ink jet recording head 1 is connected to the air buffer tank 5 of the sub ink tank 4 and the valve 16 by the tube 9 which is a pressurized flow path.
And is connected to the sub-ink tank 4 via a valve 17 by a tube 10 which is a return-side flow path.

The tube 20 which is the return side suction channel
Connects the ink receiver 2 of the ink jet recording head 1 to a pump tube 8a of a sub-pump 8, which is a suction pump, via a one-way valve 13 and a filter 12. Further, the pump tube 8a of the sub-pump 8 It is connected to the sub-ink tank 4 via In order to supply ink from the sub ink tank 4 to the air buffer tank 5, a pump tube 7a on the side of the main pump 7, which is a pressurizing pump, is connected between the sub ink tank 4 and the air buffer tank 5.

In the ink jet recording apparatus of the present invention thus constructed, when supplying ink, the valve 1
By closing the ink passages 6, 17, and 18 to maintain the ink flow path in a closed state, and then rotating the rotating member 7b of the main pump 7 in a counterclockwise direction, the ink in the ink cartridge 6 is moved in one direction. The pump tube 7 of the main pump 7 through the valve 15 and the air buffer tank 5
The ink is supplied to and stored in the sub-ink tank 4 through a, and is returned to the ink cartridge 6 through the tube 11 when it is stored to a certain degree or more. As a result, the amount of ink in the sub ink tank 4 becomes full.

An ink level sensor (not shown) is provided in the sub-ink tank 4 so that the ink supply amount can be detected, and the ink level exceeds a predetermined position. Then, the ink is returned to the ink cartridge 6 through the tube 11.

In the ink jet recording apparatus of the present invention, when performing printing by discharging ink, first, the valves 16, 17, and 18 are opened, and printing is performed only by the discharging force discharged from the ink jet recording head 1. Further, a part of the ink is supplied to the inkjet recording head 1 through the open valve 17, and another part of the ink is supplied from the sub ink tank 4 to the main pump 7 via the air buffer tank 5. The ink is supplied from the opened valve 16 to the inkjet recording head 1 via the tube 9 and refilled.

When the ink suction process is performed, the valve 16,
When the main pump 7 is rotated clockwise with the openings 17 and 18 open, the ink in the sub ink tank 4 is transferred from the air buffer tank 5 to the ink jet through the tube 9 via the open valve 16. It is supplied to the recording head 1. At this time, the ink flowing out of the other flow path of the ink jet recording head 1 is supplied to the tube 10
And is returned to the sub ink tank 4 via the opened valve 17.

The ink ejected from the nozzles of the ink jet recording head 1 and discharged to the ink receiver 2 is stored in the ink receiver 2, and the rotating member 8a of the sub-pump 8
Is rotated clockwise through the one-way valve 13 and the filter 12 and the sub-pump 8
4 and is returned to the sub ink tank 4.

In the ink jet recording apparatus having such an ink jet recording head 1 of the present invention, as shown in FIG. 1, an ink receiver 2, a one-way valve 13 from the ink receiver 2, a filter 12, and a sub pump 8
A sensor 14 is provided downstream of the filter 12 in the ink flow path between the sub-ink tank 4 and the sub-ink tank 4 via the sensor 14, and changes in the ink flow in the ink flow path, particularly, clogging of the filter 12 Is configured to be detected. In addition, appropriate means for transmitting a signal of filter clogging and filter replacement in accordance with a predetermined change in ink flow may be provided so that the sensor 14 can detect a change in ink flow in the ink flow path. it can.

The detailed structure of the sensor 14 according to the present invention is clearly shown in FIGS. As shown, the sensor 14 includes a casing 50 connected to a tube through which ink flows, and a pair of electrodes 51 provided in the casing 50 at intervals. Is connected to a control device (not shown). The electrode 51 can be made of a noble metal such as platinum, gold, silver, iridium, and vanadium, or a metal material having good conductivity such as copper, brass, and stainless steel. Is preferable because it is hard to rust, easy to manufacture, and inexpensive.

Therefore, in such a sensor 14,
If the filter 12 is not clogged, the casing 50 is filled with ink about 10 seconds after the rotation of the sub-pump 8 by the control device described above. The two electrodes 51 detect the presence of ink by being electrically short-circuited by the ink in the casing 50. However, if the filter 12 is clogged, the interior of the casing 50 will not be filled with ink even after 10 seconds have elapsed after the rotation of the sub-pump 8, so that the two electrodes 51 are electrically disconnected. The presence of ink is not detected. Therefore, in such a case,
It is determined that the filter 12 is clogged, a message that the filter 12 must be replaced because the filter 12 is clogged is displayed on an operation panel (not shown), and the user must replace the filter 12. They warn them of what they have to do.

In the present embodiment, the sensor 14 including the pair of electrodes 51 is provided in the ink flow path between the filter 12 of the ink jet recording head 1 and the sub ink tank 4. The present invention is not limited to the sensor 14 having the configuration, and a similar sensor for detecting and controlling a change in ink flow, a pressure sensor for detecting a change in ink flow as a pressure change, or the like is appropriately used. Is what you can do.

(Embodiment 2) FIG. 4 is a view showing a second embodiment of the detecting means in the ink jet recording apparatus according to the present invention. Although the detection is performed by the sensor 14 including the pair of electrodes 51 arranged at intervals in the casing 50 to be formed, in the present embodiment, as shown in FIG. And a sensor 8a which is combined to detect using a photo interrupter 53 arranged in a transverse direction substantially at right angles.

That is, as shown, the sensor 8a
Is a combination of a transmission type photointerrupter 53 and a tube 54. If the filter 12 is not clogged, the tube 54 is filled with ink about 10 seconds after the rotation of the sub-pump 8, so that the photointerrupter 53 is filled. Is continuously shielded from light for a certain period of time. Then, in such a light-shielded state, it is detected that there is ink.
However, if the filter 12 is clogged, the tube 54 is not filled with the ink even after 10 seconds from the rotation of the sub-pump 8, so that the photo interrupter 53 remains in the transmission state or intermittently blocks light. Is done. Therefore, in such a case, it is determined that the filter 12 is clogged, and a message that the filter 12 must be replaced because it is clogged is displayed on an operation panel (not shown). And warn the user that the filter should be replaced.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the constitution of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

The type and number of recording heads to be mounted are not limited to those provided only for one color ink, for example, and for a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not limited to those used as image output terminals of information processing equipment such as computers, copying apparatuses combined with readers and the like, and facsimile apparatuses having a transmission / reception function. It may take a form.

[0055]

According to the first aspect of the present invention, there is provided an ink jet recording apparatus having an ink jet recording head for discharging ink to perform recording and an ink circulating device, wherein the ink discharged to an ink flow path is provided. Since it has means for removing foreign matter from inside and means for detecting clogging of the means, it is possible to easily detect clogging or the like of the foreign matter removing means caused by the flow of ink in the ink flow path and easily and quickly. Can be processed and replaced.

In the ink jet recording apparatus according to a second aspect of the present invention, the means for removing the foreign matter has a filter, the detecting means has a sensor, and the sensor is arranged downstream of the filter. Filter clogging can be accurately detected and promptly processed.

In the ink jet recording apparatus according to the third aspect of the present invention, since the sensor has at least a pair of electrodes, a change in the ink flow can be detected by simple means, and the apparatus can be manufactured at low cost.

In the ink jet recording apparatus according to the fourth aspect of the present invention, since the sensor has a transmission type photo interrupter, it can be easily configured with a simple mechanism.

According to a fifth aspect of the present invention, in the ink jet recording apparatus, the ink circulation device has a main pump and a sub-pump, the sub-pump is disposed on an upstream side, and the filter is disposed on an upstream side of the sub-pump. And the sensor is located downstream of the sub-pump,
The ink can be constantly and reliably circulated.

According to a sixth aspect of the present invention, there is provided an ink jet recording head comprising: an ink jet recording head; an ink receiver for receiving ink ejected from the ink jet recording head; an ink tank holding ink; A main pump for supplying ink to the recording head, and a sub-pump provided in an ink flow path between the ink receiver and the ink tank, for collecting ink ejected from the ink jet recording head by the ink receiver. Then, the filter and the sensor are provided in the ink flow path from the ink receiver to the ink tank, and the clogging or the like in the ink flow path is suitably detected. The pressure can be controlled and dealt with better.

In the ink jet recording apparatus according to a seventh aspect of the present invention, if the sensor does not detect the presence of ink even after a lapse of a predetermined time after the rotation of the sub-pump, it determines that the filter is clogged. The filter can be easily and simply exchanged, and the filter and sensor set can be suitably arranged in the ink flow path.

Since the ink jet recording apparatus according to the present invention has a pressure sensor for detecting the change in the ink flow as a change in the pressure, the change in the ink flow based on the clogging of the filter can be simply determined as the pressure change. In addition, it is possible to reliably detect.

According to the ninth aspect of the present invention, since the ink tank has a sub-ink tank and an air buffer tank, the ink-jet recording apparatus can be simply configured so that the ink can be suitably supplied with a sufficient ink capacity. Can be.

In the ink jet recording apparatus according to the tenth aspect of the present invention, since an ink cartridge is connected to the ink tank, it has a sufficient ink capacity and can always supply ink satisfactorily.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an ink circulation system in a first embodiment of the ink jet recording apparatus of the present invention.

FIG. 2 shows the first embodiment of the ink jet recording apparatus of the present invention shown in FIG.
FIG. 3 is a schematic plan view showing an ink circulation system sensor according to the embodiment of FIG.

FIG. 3 is a side sectional view of the sensor of FIG. 2;

FIG. 4 is a schematic perspective view showing a second embodiment of the sensor in the ink jet recording apparatus of the present invention.

FIG. 5 is a schematic circuit diagram of an ink circulation system of a conventional inkjet recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording head 2 Ink receiver 3 Ink tank 4 Sub ink tank 5 Air buffer tank 6 Ink cartridge 7 Main pump 8 Sub pump 9 Tube 10 Tube 11 Tube 12 Filter 13 One-way valve 14 Sensor 15 One-way valve 16 Valve 17 Valve 18 One Directional valve 19 Valve 20 Tube 21 Tube 22 Tube

Claims (10)

[Claims] 1. An ink jet recording apparatus comprising: an ink jet recording head for performing recording by discharging ink; and an ink circulating device. A means for removing foreign matter in ink discharged to an ink flow path, and clogging of the means. Detecting means for detecting an ink jet recording. 2. The ink jet recording apparatus according to claim 1, wherein the means for removing the foreign substance has a filter, the detecting means has a sensor, and the sensor is arranged downstream of the filter. . 3. The ink jet recording apparatus according to claim 1, wherein the sensor has at least a pair of electrodes. 4. The ink jet recording apparatus according to claim 1, wherein the sensor has a transmission type photo interrupter. 5. The ink circulation device has a main pump and a sub-pump, the sub-pump is disposed on an upstream side, the filter is disposed on an upstream side of the sub-pump, and the sensor is disposed on a downstream side of the sub-pump. The inkjet recording apparatus according to any one of claims 1 to 4, wherein the inkjet recording apparatus is arranged. 6. An ink jet recording head, an ink receiver for receiving ink discharged from the ink jet recording head, an ink tank holding ink, and a main pump for supplying ink from the ink tank to the ink jet recording head. And a sub-pump provided in an ink flow path between the ink receiver and the ink tank. The ink discharged from the ink jet recording head by the ink receiver is collected, returned to the ink tank, and reused. 6. The ink jet recording apparatus according to claim 1, wherein the filter and the sensor are provided in an ink flow path from the ink receiver to the ink tank. 7. The filter according to claim 1, wherein the sensor determines that the filter is clogged when the sensor does not detect the presence of ink even after a certain time has elapsed after the rotation of the sub-pump. The inkjet recording apparatus according to any one of the preceding claims. 8. A pressure sensor for detecting a change in the ink flow as a change in pressure.
The inkjet recording apparatus according to any one of the preceding claims. 9. An ink jet recording apparatus according to claim 6, wherein said ink tank has a sub tank and an air buffer tank. 10. The ink tank according to claim 6, wherein an ink cartridge is connected to the ink tank.
The inkjet recording apparatus according to any one of the preceding claims.