JP2002316422A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate suction of ink from an ink tank into a subtank except when supplement of ink is required by preventing unintended movement of ink in the channel from the ink tank to the subtank incident to open/close operation of an on/off valve for ink supply except when ink is supplied. SOLUTION: An on/off valve 109 and a suction pump 107 are provided in the ink channel coupling an ink tank 105 and a subtank 103. The on/off valve has an enclosing means for bringing it into shutoff state and when shutoff state is released, the enclosing means opens the channel only during operation of the suction pump by the suction force thereof and holds the channel in a closed state when the suction pump is not operating.

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 performing recording by discharging ink from a recording means to a recording medium, and more particularly, to an ink supply path for supplying ink from an ink tank to the recording means and an ink supply path. The present invention relates to a configuration of an on-off valve provided in a path.

[0002]

2. Description of the Related Art A recording device having functions such as a printer, a copying machine, and a facsimile, or a recording device used as an output device such as a composite electronic device including a computer or a word processor, or a workstation, is based on paper based on the recording information. An image (including characters and symbols) is recorded on a recording medium (recording material) such as a cloth, a plastic sheet, and an OHP sheet. The recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type and the like according to a recording method.

[0003] In a serial type recording apparatus that performs recording while performing main scanning in a direction crossing the recording medium conveyance direction (paper feeding direction and sub-scanning direction), a recording means mounted on a carriage that moves along the recording medium. An image is recorded (main scanning) by a (recording head), a predetermined amount of paper is fed (pitch conveyance as a sub-scanning) after printing of one line is completed, and then the next recording medium is stopped again. By repeating the operation of printing (main scanning) the image of the row, the printing of the entire printing medium is performed. On the other hand, in a line type printing apparatus that performs printing only by sub-scanning in the transport direction of a printing medium (recording material), the printing medium is set at a predetermined printing position, and printing is performed for one line at a time. By performing a predetermined amount of paper feed (pitch feed) and repeating the operation of collectively recording the next line, the entire recording medium is recorded.

Among them, an ink jet type recording apparatus (ink jet recording apparatus) performs recording by ejecting ink from a recording means (recording head) to a recording medium. High-definition images can be recorded at high speed, and can be recorded on plain paper without requiring special processing.The running cost is low and the non-impact method reduces noise,
In addition, there is an advantage that it is easy to record a color image using various types of inks (for example, color inks). In addition, there are various requirements for the material of a recording medium (recording material) in an ink jet recording apparatus. In recent years, developments in response to these requirements have been advanced, and paper (thin paper or processed paper) which is a normal recording medium has been developed. ), Resin sheets (OHP, etc.), cloth, leather, non-woven fabric,
Further, a recording apparatus using a metal or the like as a recording medium has been used.

[0005] As an ink supply device for supplying ink from an ink tank to a recording head in the ink jet recording apparatus, an ink supply path is provided corresponding to the recording head, and ink supplied from the ink tank is supplied into the ink supply path. A sub-tank for storing and a suction pump for transporting ink into the sub-tank are provided. The sub-tank is connected to one of the suction pumps (discharge side), and a recording means is connected to the other (suction side) of the suction pump. A flow path leading to a recovery tub for receiving waste liquid from the tank and a flow path leading to the ink tank are connected, and a first opening / closing valve (recycle valve) is provided in a flow path between the recovery tub and the suction pump.
And a second on-off valve (supply valve) is provided between the ink tank and the suction pump, and the flow path is switched by switching between the first on-off valve and the second on-off valve. An ink supply device configured to switch is used.

FIG. 8 is a vertical cross-sectional view showing the conventional on-off valve when the flow path is cut off in the conventional example, and FIG. 9 is a vertical cross-sectional view showing the on-off valve of FIG. 8 when the flow path is opened. The first on-off valve (recycle valve) and the second on-off valve (supply valve) have substantially the same structure, and FIGS. 8 and 9 show a common on-off valve structure. Things. 8 and 9
In the above, the ink is sucked into the inside of the valve from the side A, which is the side that communicates with the ink tank in the case of the second on-off valve (supply valve) (the side that communicates with the recovery tub in the case of the first on-off valve (recycle valve)). Then, it flows out from the side B which is the outlet side of these on-off valves (all on the suction pump side).

[0008] In the flow path shut-off state shown in FIG. 8 (when the valve is closed), the flow path from the side A to the side B is a rubber member (sealed) on which the elastic force of the sealing spring 206 acts via the stopper collar 207. (Stop member) 208. On the other hand, in the flow path open state shown in FIG. 9 (a state in which the valves are communicated), the plate-like member 205 is pushed upward by a valve driving mechanism (not shown), and is fitted via the sliding collar 204 and the opening spring 203. When the mating stopper 202 moves upward, the shaft 201 to which the fitting stopper 202 is fixed moves upward. As a result, the rubber member (sealing member) 208 attached to the lower end of the shaft 201 communicates with the suction pump, separates from the inlet of the flow path B, and opens the flow path from the inlet A to the outlet B (communication). ).

In this case, the spring pressures of the open spring 203 and the closed spring 206 always satisfy the relationship of open spring 203> closed spring 206. When the plate member 205 is first pushed upward, the closed spring is closed. 206 is compressed and the valve is opened. When the plate-like member 205 is further pushed upward, the stopper collar 207 comes into contact with the lid member 209, and the opening spring 203 is compressed. In the case where the state is changed to the closed state again, the above-described operation process is reversed.

[0009]

However, in the conventional on-off valve shown in FIGS. 8 and 9, the internal volume of the valve increases and decreases as the valve opens and closes. That is, the internal volume when the valve is closed as shown in FIG. 8 is X + Y,
Although the internal volume at the time of opening the valve shown in FIG. 9 is represented by Z, their magnitude relation is clearly (X + Y) <Z. Therefore, if the state of the on-off valve shifts from closed (closed) → open → closed → open → closed ... then the internal volume of the on-off valve decreases → increases → decreases → increases → decreases ... repeatedly. become. As a result, the opening / closing valve repeats the phenomenon that ink is drawn in from the outside of the valve and discharged to the outside each time the opening / closing operation is performed.

More specifically, a one-way valve is provided immediately downstream of the on-off valve and immediately before the suction pump, so that when one of the recycle valve or the supply valve is opened, ink is drawn from the recovery tub or the ink tank into the valve. When one of the recycle valve and the supply valve is closed, the ink is dispersed into the ink returned to the recovery tub or the ink tank and the ink discharged to the suction pump.
However, even when there is no one-way valve downstream of the on-off valve, it is clear that the same phenomenon may occur depending on the balance between the flow resistance on the upstream side and the flow resistance on the downstream side of the on-off valve.

Such a phenomenon is caused by a recycle valve (the first valve) installed in a circulation channel for recycling ink.
However, the supply valve (the second on-off valve) for supplying ink from the ink tank to the sub-tank has an ink tank upstream of the supply valve. Ink will be supplied. For example, even when it is not necessary to replenish the ink, a phenomenon that the ink is replenished from the ink tank to the sub-tank may occur.

Specifically, for example, in an ink jet recording apparatus using a plurality of types of inks, a plurality of stations (a plurality of stations) such as an ink supply apparatus for supplying ink from a plurality of ink tanks to each of a plurality of recording heads. When the ink supply paths are arranged in parallel,
When it becomes necessary to supply ink to any one of the stations, the supply valves (second on-off valves) of all stations are simultaneously shifted to the open state. The ink is sucked from the ink tank into the ink circulation path even when there is no need to replenish the ink in the sub-tank (when the ink supply mode is not executed) by the opening / closing operation of the supply valve which is the opening / closing valve 2). The sucked ink may be introduced into the sub tank.

Alternatively, a drive transmission (transmission mechanism) by rotation of a gear or the like is commonly used for opening and closing the recycle valve and the supply valve, and the opening and closing of both the on-off valves is switched by one-way rotation. In some cases, the supply valve is opened and closed unnecessarily by switching the mode.
In this case, even in the case of an ink supply device that does not have a plurality of stations (an ink supply device that includes one station), ink may be unintentionally supplied into the circulation path as described above.

When an undesired ink supply phenomenon occurs due to the repetition of the opening / closing operation of the opening / closing valve (particularly, the supply valve) as described above, it is particularly inconvenient when the ink supply amount is smaller than the ink consumption amount for printing. However, at the station where the ink supply amount due to unintended ink supply exceeds the ink consumption amount due to recording, the ink level in the sub tank eventually exceeds the upper limit position, and the ink overflows. In some cases, the overflowed ink leaks to the outside through an air opening provided in the upper part of the sub tank.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problems, and an object of the present invention is to provide an opening / closing valve for an opening / closing valve in an ink supply path for supplying ink from an ink tank to recording means. When the release of power is repeated, the phenomenon that ink is drawn into and discharged from the on-off valve when the power is repeatedly released can be eliminated. It is an object of the present invention to provide an ink jet recording apparatus which can prevent undesired ink movement in a flow path leading to an ink tank, and can eliminate suction of ink from an ink tank to a sub tank when ink replenishment is not required.

[0016]

Means for Solving the Problems The present invention (claim 1) provides:
In order to achieve the above object, in an ink jet recording apparatus which performs recording by discharging ink from a recording unit to a recording medium, the recording unit includes an ink tank, and the recording unit for supplying ink from the ink tank to the recording unit. And a sub-tank for storing the ink supplied from the ink tank and a pump for transporting the ink into the sub-tank are provided in the ink supply path, The sub-tank is connected to one of the pumps, and the other end of the pump is connected to a flow path leading to a recovery tub for receiving waste liquid from recording means and a flow path leading to the ink tank. Providing a first on-off valve in a flow path between the ink tank and the pump, and providing a second on-off valve between the ink tank and the pump; Switching means for switching the flow path by switching between opening and closing of the on-off valve and the second on-off valve, wherein at least a second on-off valve of the first on-off valve and the second on-off valve is When the pump is transporting the ink from the recovery tub to the sub-tank, the pump has sealing means that shuts off the flow path by receiving an operating force, and the sealing means is configured to release the operating force when the operating force is released. When the pump is driven, the flow path is opened by the pressure generated by the pump, and when the pump is not driven, the flow path is kept closed by an elastic force smaller than the pressure generated by the pump. It is characterized by comprising.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a plurality of recording means are provided, and a plurality of ink supply paths corresponding to each of the plurality of recording means are provided. The holding means for holding the flow path closed by an elastic force smaller than the pressure generated by the pump is a spring set to open the flow path with respect to the pressure generated by the pump. The pump may be configured as a spring urging means for urging the flow path in a sealing direction by an elastic force, or a holding means for holding the flow path closed by an elastic force smaller than a pressure generated by the pump. The above-mentioned object can be achieved more efficiently by using a rubber urging means which urges the flow path in a sealing direction by an elastic force of rubber set so as to open the flow path against the generated pressure. To achieve .

[0018]

Embodiments of the present invention will be specifically described below with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. FIG. 6 is a schematic perspective view of an ink jet recording apparatus suitable for applying the present invention. The ink jet recording apparatus of FIG.
An example of an ink jet recording apparatus provided with a plurality of line type ink jet recording heads (four in the illustrated example) capable of full color recording is shown. In FIG. 1, reference numerals 1101 and 1102 denote a pair of rollers for sandwiching a recording medium (recording material) 1103 such as a sheet of paper or a thin plastic plate and conveying the recording medium 1103 in the sub-scanning direction (conveying direction) indicated by an arrow F. is there. 101Bk, 101Y, 101M, 10
Reference numeral 1C denotes a full multi-type ink jet recording head in which ejection ports are arranged over substantially the entire width of the recording medium 1103. Hereinafter, a case where any one or all of these recording heads (recording means) is referred to Is simply referred to as recording means (recording head) 101.

In the case of full-color printing, for example, black, yellow, magenta, and cyan are used as ink colors ejected from the four print heads 101. In the illustrated example, four ink jet print heads 101 print. They are arranged in this order from the upstream side in the medium transport direction (from the bottom in the drawing). 1106 is a recovery unit.
In the ejection recovery process, the recovery process is performed between the print head 101 and the print medium 1103 to face each print head 101 instead of the print medium 1103. Further, each of the ink jet recording heads 101 is mounted on the head mounting portion 1107 with its mutual positional relationship being regulated. As described above, an inkjet recording apparatus suitable for applying the present invention, that is, a head mounting unit 1107 for mounting the inkjet recording head 101,
The recording head 10 mounted on the head mounting portion 1107
An inkjet recording apparatus having transport units 1101 and 1102 for transporting the recording medium 1103 to one recording position is configured.

FIG. 1 is a schematic diagram showing the configuration of an ink supply path in an embodiment of an ink jet recording apparatus to which the present invention is applied. FIG. 1 shows a configuration of one ink supply device (one station) for supplying ink from one ink tank to a corresponding one of recording means. In the case of having a plurality of ink tanks and a plurality of recording means corresponding to the above, a plurality of ink supply devices similar to the ink supply device shown in FIG. 1 are arranged in parallel. The following embodiment will be described with an example of an ink jet recording apparatus having such a plurality of ink supply devices (a plurality of stations).

In FIG. 1, ink required for recording is supplied from a detachable ink tank 105 to a sub-tank 103 and is once stored in the sub-tank 103. The ink in the ink tank 105 is stored in, for example, a pack-shaped container (ink tank) that contracts as it is sucked out. An ink level sensor 120 composed of electrodes is inserted and installed in the sub-tank 103. The ink level sensor 120 is located at the position m of the ink level in the ink full state and the ink level level in the ink empty state. The presence or absence of ink is detected by detecting the position n.

The transport of the ink to each part is performed by the pressurizing pump 106.
And a suction pump 107. The pressurizing pump 106 is simultaneously driven with each station (a plurality of ink supply paths corresponding to a plurality of recording units) by a pressurizing pump motor (not shown). On the other hand, the suction pump 107 is driven by a suction pump motor (not shown), but is selected for each suction pump of each station by an electromagnetic clutch (not shown) provided in the middle of a transmission mechanism to the suction pump of each station. It is configured to be able to be driven in a dynamic manner.

Each of the pressure pump 106 and the suction pump 107 has one-way valves 110, 111, 112 on its upstream side (suction side) and downstream side (discharge side).
113 is provided, so that the pressure pump 106 can rotate only in the direction of arrow C and the suction pump 107 can rotate only in the direction of arrow D. The ink discharged from the ejection port of the recording head 101 as the recording means
Caught (received) by This recovery tub 10
Flow path (tube) 1 between 2 and the suction pump 107
A recycle filter 119 and a recycle valve (first opening / closing valve) 108 are arranged in 16, and a supply valve (second tube) 118 is provided in a flow path (tube) 118 between the ink tank 105 and the suction pump 107. Opening / closing valve) 109 is disposed.

The first on-off valve (recycle valve) 108
The second open / close valve (supply valve) 109 is driven by a drive device (not shown) so that the open / close state of each station is simultaneously switched. However, each recycling valve 108
The open / close state of each supply valve 109 is maintained in the opposite state, and control is performed such that when one is open (flow state), the other is closed. By switching this appropriately, when the suction pump 107 is driven, either ink suction from the recovery tub 102 or ink suction from the ink tank 105 is selectively performed.

The recording means (recording head) 101 is an ink jet recording means for discharging ink using thermal energy, and has an electrothermal converter for generating thermal energy. The ink jet recording means 101 performs recording by causing ink to be ejected from an ejection port by utilizing a pressure change caused by growth and shrinkage of bubbles caused by film boiling caused by thermal energy applied by the electrothermal transducer. Things.

FIG. 7 is a partial perspective view schematically showing the structure of the ink ejection section of the recording head 101. 7, a substrate (base plate) 81 of the recording head 101 is shown.
A plurality of electrothermal converters 82 and wirings corresponding thereto are formed thereon by a manufacturing process (thin film forming method or the like) similar to that of a semiconductor with a layer of the thin film 83 interposed therebetween. As shown, each electrothermal transducer 82 has a respective discharge port 8.
9 and the liquid passage 86. On the substrate (base plate) 81 (the thin film 8 on the substrate 81)
3), a liquid path forming member 84 having a plurality of liquid path walls 84A formed in parallel on a lower surface at predetermined intervals is joined. Further, a top plate 85 is joined to the upper surface of the liquid path forming member 84.

The liquid passages 86 are formed between the liquid passage walls 84A. The liquid passage forming member 84 has the electrothermal transducers 82 arranged at predetermined positions inside the liquid passages 86. It is positioned and joined in such a positional relationship. Each liquid passage wall 8
4A has a predetermined length, and the rear end of each liquid path 86 communicates with a common liquid chamber 87 formed between the liquid path forming member 84 and the substrate (base plate) 81 (or thin film 83). are doing. On the other hand, the other end (front end) of each liquid passage 86 is opened at the discharge port surface 88 of the recording head 101 (the front surface on which a plurality of discharge ports 89 are arranged), and the discharge ports 89 are formed by the respective openings. Have been.

Thus, the electrothermal converter 8 such as a heating resistor is provided.
An ink jet recording head 101 is configured to energize (apply pulse voltage) 2 to generate heat, thereby causing the ink in the liquid passage 86 to boil, and ejecting ink droplets from the ejection port 89 by a change in pressure at that time. ing. The recording head 101 is mounted so that the arrangement direction of the plurality of ejection ports 89 crosses (substantially orthogonally) the transport direction of the recording medium (recording paper or the like), and the distance between the ejection port surface 88 and the recording medium (the paper interval). The distance) is set to, for example, about 0.3 to 2.0 mm.

Hereinafter, an operation method and an ink flow path in each operation mode of the ink jet recording apparatus having the ink supply path shown in FIG. 1 will be described. First, a recording mode in which recording is performed by discharging ink from a recording head 101 as recording means onto a recording medium such as recording paper will be described. The ink in the print head 101 is sequentially consumed by the ink discharge in the print mode. At this time, the ink replenishment is automatically performed by the suction force due to the capillary phenomenon generated at the discharge port of the print head 101. This ink replenishment is performed by sub-tank 103 → pressure pump 106 → flow path (tube) 11
4 → an ink flow path passing through the print head 101; and a sub-tank 103 → a flow path (tube) 115 → an ink flow path passing through the print head 101.

Next, an ink circulation mode in which the pressure pump 106 and / or the suction pump 107 are operated to circulate ink will be described. 1 in ink circulation mode
As one operation sequence, the recycle valve 108 as the first on-off valve is opened by the driving means (not shown),
The supply valve 109 as an opening / closing valve is closed. In addition, an example in which the electromagnetic clutch (not shown) provided in the transmission mechanism between the suction pump motor (not shown) and the suction pump of each station is in a clutch-on (drive transmission) state in all stations. More specifically, when the pressurizing pump 106 and the pulling pump 107 are driven in this state, the ink in the sub tank 103 is
6 and the flow path 114 are supplied to the recording head 101.

The ink supplied to the recording head 101 is
On the one hand, it is discharged from the discharge port, and on the other hand, it is returned to the sub tank 103 again through the flow path 115. The ink discharged from the discharge port of the recording head 101 is caught by the recovery tub 102 and is suctioned by the suction pump 107 to cause the flow path 116 → recycle filter 119 → recycle valve 108 → suction pump 107 → flow path. It is returned to the sub tank 103 again through 117.

Next, an ink supply mode for supplying ink from the ink tank 105 to the sub tank 103 will be described. In a plurality of stations configured by providing a plurality of stations (ink supply devices) as shown in FIG. 1, the liquid level in the sub tank 103 becomes Empty (level n) in any one of the stations. When the ink level sensor 120 detects that the recycle valve (first open / close valve) 108 is closed by a driving unit (not shown), the supply valve (second
Open / close valve) 109 is opened. Further, the clutch provided in the transmission mechanism from the suction pump motor to the suction pump is set to a state in which the driving force is transmitted to the suction pump of only the station where the liquid level in the sub tank 103 is n. You.

When the suction pump motor is driven in this state, power is transmitted only to the suction pump of the selected station, and as a result, only at the selected station,
From the ink tank 105 to the tube 118 → supply valve (second
The ink is sucked into the suction pump 107 through the on-off valve 109, and the ink is supplied into the sub tank 103 through the tube 117. Then, the sub tank 103
When the ink level sensor 120 detects that the ink level has reached the level m due to the supply of ink to the ink, the drive transmission by the electromagnetic clutch is canceled to stop the suction pump motor (not shown). The operation in the ink supply mode ends.

On the other hand, the ink liquid level becomes level m within the specified time.
Is not reached, it is determined that there is no ink in the ink tank 105. Depending on the timing, the ink supply may be performed by simultaneously operating the suction pump 107 at a plurality of stations. In this case, the drive transmission by the electromagnetic clutch is sequentially canceled at each station where the ink level reaches the level m. Then, the operation of the suction pump 107 is stopped. Also, a recycle valve 1 as a first on-off valve
08 and the supply valve 109 serving as the second on-off valve have substantially the same configuration, and the downstream side of these valves is joined before the one-way valve 113 on the upstream side of the suction pump 107 to form a common flow. Integrated into the road.

FIG. 2 is a longitudinal sectional view showing a locked state of the first embodiment of the on-off valve in FIG. 1, and FIG. 3 is a state of the first embodiment of the on-off valve in the unlocked state. FIG. Here, the on-off valve is the supply valve (second on-off valve)
The case of 109 will be described as an example.
The recycle valve (first on-off valve) 108 is also the supply valve 1
09 has the same configuration as that of FIG.

2 and 3, the ink tank 105 is connected to the E side, and the suction pump 107 is connected to the F side. In the valve closed state (closed state) shown in FIG. 2, the plate-like member 505 receives a driving force (operating force) and is pushed upward, so that the stopper collar 502 moves upward via the collar 504 and the lock spring 503. The shaft 50 fixed to the stopper collar 502
1 also moves upward, and the elastic member (sealing member, rubber member) 508 attached to the lower end portion of the shaft 501 is pressed against the lower surface of the opening peripheral portion 509 of the valve main body. The flow path from the inlet E on the ink tank 105 side to the outlet F on the suction pump 107 side is completely shut off. That is, it is in the locked state. Reference numeral 51
Reference numeral 1 denotes a leakage prevention member made of a rubber-like elastic material for sealing the inside of the on-off valve from the outside air (outside).

In the lock state shown in FIG. 2, when the suction pump 107 operates during the above-described ink circulation, the liquid chamber (outlet side) F on the suction pump 107 side is in a negative pressure state due to the flow path resistance of the recycle filter 119 and the like. . However, even if a downward force (suction force) acts on the shaft 501 due to the negative pressure (negative pressure on the suction pump side) generated at this time, the shaft 501 moves downward and the rubber member The (sealing member) 508 is set to a spring having a sufficiently strong spring force (elastic force) so as not to be separated from the lower surface of the opening peripheral portion 509.

In the ink supply mode for supplying ink from the ink tank 105 to the sub-tank 103, as shown in FIG. 3, a second open / close valve (supply valve) 109 is provided.
Is a state at the time of unlocking, that is, a state where the plate-shaped member 505 is pushed down to a position where it is retracted from the lock collar 504 by a driving unit (not shown). In this unlocked state, the locked state is released at this point, but the shaft 501 is elastically biased upward together with the biasing collar 510 by the biasing spring 506 mounted in the on-off valve. Load), the elastic member (rubber member, sealing member) 508 is still pressed against the lower surface of the opening peripheral portion 509, and the on-off valve 109
The flow path from the inlet side E to the outlet side F is kept sealed.

However, the spring force of the urging spring 506 is set to a predetermined value sufficiently smaller than the spring force of the lock spring 503. Therefore, as described above, in the ink supply mode, the suction pump 107 is driven at a station that requires ink replenishment, and this suction pump 107
When a negative pressure is generated at the outlet side (ink liquid chamber) F of the supply valve (second opening / closing valve) 109 by the operation of, the negative pressure causes the shaft 501 and the sealing member 508 to contact the urging spring 506. It is pushed down against it, as shown in FIG.
The sealing member (rubber member) 508 is sufficiently separated from the lower surface of the opening peripheral portion 509, and the ink flows through the supply valve (second opening / closing valve) 109 as shown by an arrow g.

However, in a station that does not require ink replenishment, no negative pressure is generated in the ink liquid chamber (outlet side) F because the suction pump 107 does not operate.
The elastic member (rubber member,
The sealing member 508 is still kept pressed against the lower surface of the opening peripheral portion 509, and the on-off valve 1
The flow path from the entrance side E to the exit side F of the cell 09 remains sealed and does not communicate.

FIG. 4 shows a case where a drive transmission (transmission mechanism) by rotation of gears and the like is commonly used for opening and closing operations of a recycle valve 108 as a first on-off valve and a supply valve 109 as a second on-off valve. A timing chart of an opening / closing operation when switching the opening / closing of these on / off valves by one-way rotation is shown. According to the above-described embodiment described with reference to FIGS. 1 to 3, an ink supply device in which a plurality of stations for performing the opening / closing operation of the first opening / closing valve 108 and the second opening / closing valve 109 is arranged in parallel. In this case, it is possible to eliminate the phenomenon that the opening / closing valve unnecessarily sucks or discharges ink when switching the mode. Therefore, the sub-tank 1 is inadvertently supplied with ink into the circulation path.
It is possible to eliminate the phenomenon that the ink in the ink tank 03 overflows or the ink leaks from the sub tank 103 to the outside (ink leakage).

FIG. 5 is a longitudinal sectional view showing a state when the lock of the second embodiment of the on-off valve in FIG. 1 is released. In this embodiment, as shown in FIG. 5, the shape of the leakage prevention member 611 made of a rubber-like elastic material mounted inside the on-off valve is devised, so that the on-off valve is locked to the leakage prevention member. The function of the holding means (the urging spring 506 and the urging collar 510 in FIG. 2) for maintaining the airtightness when the suction pump 107 is not operated at the time of release is provided so as to serve also as the holding means. Thus, the configuration is further simplified.
That is, the second embodiment of FIG. 5 is mounted inside the on-off valve as holding means for holding the flow path closed when the on-off valve is unlocked by an elastic force smaller than the pressure generated by the suction pump 107. The elastic force of the rubber of the leakage prevention member 611 itself made of a rubber-like elastic material is used.

In FIG. 5, a leakage prevention member 611 made of a rubber-like elastic material and mounted inside the on-off valve is assembled to the shaft 501 in a state of being elastically deformed by a predetermined amount. By configuring the rubber elastic force against the elastic deformation to act in the upward direction indicated by the arrow H, the airtightness is maintained when the suction pump 107 is not driven even when the on-off valve is unlocked (open state). Can be. In the second embodiment of FIG. 5, the use of the above-described leakage prevention member 611 allows the first embodiment of FIG.
The urging spring 506 and the urging collar 510 in the embodiment are omitted. The second embodiment of FIG. 5 is different from the first embodiment described with reference to FIGS. 1 to 3 in the points described above, but has substantially the same configuration in other points, and thus has the same operation and effect. Is played.

The embodiment described above relates to an ink jet recording apparatus which performs recording by discharging ink from a recording means to a recording medium.
5 and ink supply paths 118, 117, and 114 provided corresponding to the recording means for supplying ink from the ink tank to the recording means. And a pump 107 for transporting the ink into the sub-tank. The sub-tank is connected to one of the pumps, and the other of the pumps receives waste liquid from the recording unit. A flow path 116 leading to the recovery tub 102 for receiving the ink is connected to a flow path 118 leading to the ink tank, and a first opening / closing valve 108 is provided in a flow path between the recovery tub and the pump. A second on-off valve 109 is provided between the ink tank and the pump, and the flow path is switched by opening and closing the first on-off valve and the second on-off valve. Has a switching means for switching, at least a second of said first on-off valve and the second on-off valve
Opening / closing valve 109 has sealing means for receiving an operating force when the pump is transporting the ink from the recovery tub to the sub-tank, thereby shutting off the flow path. When the pump 107 is released, the flow path is opened by the pressure generated by the pump 107 when the pump 107 is driven, and the elastic force (506, 611) smaller than the pressure generated by the pump when the pump 107 is not driven. ) To keep the flow path closed.

Further, the embodiment described above has a configuration in which a plurality of recording means 101 are provided, and a plurality of ink supply paths corresponding to each of the plurality of recording means are provided. Further, in the first embodiment shown in FIGS. 2 and 3, the holding means for holding the flow path closed by an elastic force smaller than the pressure generated by the pump 107 is provided for the pressure generated by the pump. It has a structure that is a spring urging unit that urges the flow path in a sealing direction by the elastic force of a spring 506 that is set so as to open the flow path. further,
In the second embodiment shown in FIG. 5, the holding means for holding the flow path closed with an elastic force smaller than the pressure generated by the pump 107 opens the flow path for the pressure generated by the pump. A rubber urging means for urging the flow path in the sealing direction by the elastic force of the rubber 611 set as described above is provided.

According to the embodiment described above, even when the opening and closing of the sealing means for shutting off the on-off valve 109 is repeated, the phenomenon of drawing and discharging ink into the on-off valve can be eliminated. Accordingly, it is possible to prevent undesired ink movement in the flow path from the ink tank 105 to the sub tank 103 due to the opening / closing operation of the opening / closing valve 109 other than when the ink is supplied. , Ink suction from the ink tank 105 to the sub-tank 103 can be eliminated, so that it is possible to reliably prevent the ink from overflowing into the sub-tank 103 and the ink in the sub-tank 103 from leaking to the outside. .

In the above embodiment, a line recording method (line type recording apparatus) in which recording is performed only by sub-scanning using a long line type recording means having a length covering the entire width or a part of the recording medium. The present invention has been described by taking the case of example) as an example, but the present invention can be similarly applied to a serial type recording apparatus that performs recording while moving a recording unit (recording head) in the main scanning direction. The effect can be achieved. Further, the present invention can be freely implemented regardless of the number of recording heads (recording means).
In addition to a recording device that records with one recording device, a recording device that uses a plurality of recording devices, or a gradation recording device that uses a plurality of recording devices that record the same color at different densities, and a combination of these recording devices The present invention can be similarly applied to the device, and can achieve the same effect.

Further, the present invention uses a replaceable ink jet cartridge in which the recording means and the ink tank are integrated, a structure in which the recording means and the ink tank are separated, and the space between them is connected by an ink supply tube or the like. ,
The present invention can be similarly applied to any arrangement of the recording means (recording head) and the ink tank, and the same effects can be obtained. In the case of an ink jet recording apparatus, for example, the present invention can be applied to an apparatus using a recording unit using an electromechanical transducer such as a piezo element. An excellent effect can be obtained in an ink jet recording apparatus using the above recording means. According to such a method, it is possible to achieve higher density and higher definition of recording.

[0049]

As is apparent from the above description, according to the first aspect of the present invention, in an ink jet recording apparatus for performing recording by discharging ink from a recording means to a recording medium, the recording means, the ink tank, and the ink An ink supply path provided corresponding to the recording means for supplying ink from the tank to the recording means, and a sub-tank for storing the ink supplied from the ink tank in the ink supply path. And a pump for transporting ink into the sub-tank is provided. One of the pumps is connected to the sub-tank, and the other of the pump has a flow path leading to a recovery tub for receiving waste liquid from recording means, and A flow path leading to the ink tank is connected, and a first opening / closing valve is provided in a flow path between the recovery tub and the pump, and the ink tank is connected to the ink tank. A second opening / closing valve provided between the first opening / closing valve and the second opening / closing valve, wherein the first opening / closing valve has a switching unit for switching the flow path by switching between opening and closing of the first opening / closing valve and the second opening / closing valve; And at least a second on-off valve of the second on-off valve has a sealing means for receiving an operating force when the pump is transporting ink from the recovery tub to the sub-tank to shut off a flow path. , The sealing means,
When the operating force is released, the flow path is opened by the pressure generated by the pump when the pump is driven, and by an elastic force smaller than the pressure generated by the pump when the pump is not driven. Since the configuration is such that the flow path is kept closed, it is possible to eliminate the phenomenon that ink is drawn into and discharged from the on-off valve when the application and release of the operating force of the sealing means are repeated. This prevents undesired ink movement in the flow path from the ink tank to the sub-tank due to the opening / closing operation of the on-off valve at times other than when ink is supplied. Provided is an ink jet recording apparatus which can eliminate ink suction into the ink jet recording apparatus.

According to the second to fourth aspects of the present invention, in addition to the configuration of the first aspect, a plurality of recording means are provided, and a plurality of ink supply paths corresponding to each of the plurality of recording means are provided. The holding means for holding the flow path closed by an elastic force smaller than the pressure generated by the pump is spring set so as to open the flow path for the pressure generated by the pump. A spring urging means for urging the flow path in a sealing direction by an elastic force of a spring, or a holding means for holding the flow path closed by an elastic force smaller than a pressure generated by the pump; With respect to the pressure generated by the pump, the rubber urging means for urging the flow path in the sealing direction by the elastic force of rubber set to open the flow path, so that it is more efficient, Applying the operating force of the sealing means It is possible to eliminate the phenomenon that the ink is drawn into and discharged from the on-off valve when the release is repeated, so that the flow path from the ink tank to the sub-tank with the on-off operation of the on-off valve except at the time of supplying the ink. Can prevent undesired ink movement,
Provided is an ink jet recording apparatus capable of eliminating suction of ink from an ink tank to a sub tank when ink replenishment is not necessary.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an ink supply path in an embodiment of an inkjet recording apparatus to which the present invention is applied.

FIG. 2 is a vertical cross-sectional view showing a locked state of the first embodiment of the on-off valve in FIG. 1;

FIG. 3 is a longitudinal sectional view showing a state at the time of unlocking of the first embodiment of the on-off valve in FIG. 1;

FIG. 4 is a table illustrating the timing of opening / closing control of two on-off valves in FIG. 1;

FIG. 5 is a longitudinal sectional view showing a state at the time of unlocking of a second embodiment of the on-off valve in FIG. 1;

FIG. 6 is a schematic perspective view of an ink jet recording apparatus suitable for applying the present invention.

FIG. 7 is a partial perspective view schematically illustrating a structure of an ink discharge unit of the recording unit in FIG.

FIG. 8 is a longitudinal sectional view showing a state where an on-off valve used in an ink supply path of a conventional ink jet recording apparatus is locked.

9 is a longitudinal sectional view showing a state when the lock of the on-off valve in FIG. 8 is released.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Recording means (recording head) 102 Recovery tub 103 Sub tank 104 Atmospheric opening 105 Ink tank 106 Pressure pump 107 Suction pump 108 First open / close valve (recycle valve) 109 Second open / close valve (supply valve) 114 Flow path ( Tube) 115 Channel (Tube) 116 Channel (Tube) 118 Channel (Tube) 119 Recycle Filter 120 Ink Liquid Level Sensor 501 Shaft 502 Stopper Collar 503 Lock Spring 504 Collar 505 Plate Member 506 Urging Spring 508 Elastic Member (Rubber) 509) Opening edge 510 Energizing collar 511 Leakage prevention member 611 Leakage prevention member 1101 Transport roller 1102 Transport roller 1103 Recording medium 1106 Recovery unit 1107 Head mounting section

Claims (6)

[Claims] 1. An ink jet recording apparatus which performs recording by discharging ink from a recording unit to a recording medium, wherein the recording unit and the ink tank correspond to the recording unit for supplying ink from the ink tank to the recording unit. A sub-tank for storing the ink supplied from the ink tank and a pump for transporting the ink into the sub-tank are provided in the ink supply path. The sub-tank is connected to one of the pumps, and the other of the pump is connected to a flow path leading to a recovery tub for receiving waste liquid from recording means and a flow path leading to the ink tank. A first on-off valve is provided in a flow path between the pump and a second on-off valve between the ink tank and the pump; And switching means for switching the flow path by switching the opening and closing of the second on-off valve. At least a second on-off valve of the first on-off valve and the second on-off valve, wherein the pump is A sealing means for receiving an operating force while transporting ink from the recovery tub to the sub-tank to shut off a flow path, wherein the sealing means is configured to drive the pump when the operating force is released. When the pump is not operated, the flow path is opened by the pressure generated by the pump, and when the pump is not driven, the flow path is closed by an elastic force smaller than the pressure generated by the pump. An ink jet recording apparatus. 2. The ink jet recording apparatus according to claim 1, comprising a plurality of recording means, and a plurality of ink supply paths corresponding to each of the plurality of recording means. 3. A holding means for holding the flow path closed by an elastic force smaller than the pressure generated by the pump is spring-set so as to open the flow path with respect to the pressure generated by the pump. 3. An ink jet recording apparatus according to claim 1, wherein said ink jet recording apparatus is a spring urging means for urging said flow path in a sealing direction by an elastic force of said spring. 4. The holding means for holding the flow path closed by an elastic force smaller than the pressure generated by the pump is set so as to open the flow path with respect to the pressure generated by the pump. 2. A rubber urging means for urging said flow path in a sealing direction by an elastic force of rubber.
Or the inkjet recording apparatus according to 2. 5. The ink jet recording device according to claim 1, wherein the recording device is an ink jet recording device including an electrothermal converter that generates thermal energy used for discharging ink. 3. The ink jet recording apparatus according to claim 1. 6. The ink jet recording apparatus according to claim 5, wherein said ink jet recording means discharges the ink from a discharge port using film boiling generated in the ink by thermal energy generated by the electrothermal transducer. apparatus.