JP6540714B2 - Degassing device and inkjet recording device - Google Patents

Description

  The present invention relates to a degassing apparatus and an inkjet recording apparatus.

  2. Description of the Related Art Conventionally, a degassing device is provided in an ink flow path of an ink jet recording apparatus. When the ink contains a gas (air), there arises a problem that the discharge failure of the ink from the nozzle opening occurs due to the factor that the pressure applied when discharging the ink is not properly transmitted to the ink. By providing the degassing device and removing the gas in the ink, it is possible to prevent the occurrence of such a problem and eject the ink normally.

  In the degassing apparatus, conventionally, a gas permeable membrane is used as the degassing membrane to contact one side with the ink, and the other side is in the flowing ink by sucking the gas with a vacuum pump (vacuum suction unit). Many are used that have a configuration in which the gas is drawn into the vacuum path for degassing. In this degassing apparatus, the pressure difference always occurs on both sides of a very thin (eg, about 10 μm) gas permeable membrane, etc., thereby causing defects in the gas permeable membrane and an increase in the period of use, etc. Deterioration or breakage may occur as a result. If deterioration or damage occurs, the ink leaks to the vacuum path, and the degassing performance decreases, which causes ejection failure. Furthermore, normal ink supply and ink ejection are not performed, and image formation is stopped. You need to

On the other hand, Patent Document 1 discloses a gas-liquid separator (chamber) provided on the pressure reducing side in consideration of the fact that the amount of leakage of the liquid (ink) gradually increases as the gas permeable membrane gradually deteriorates. There is disclosed a technique for detecting the deterioration of the gas-permeable membrane by detecting the change in the amount of liquid (level of liquid level, etc.) stored inside with a sensor.
In addition, as a method of detecting ink leakage due to breakage of a gas permeable film, in Patent Document 2, the bottom of a chamber provided in the middle of a vacuum path is inclined, and the leaked ink is provided at the lowest part of the inclined surface. There is disclosed a technique for detecting an ink leak by quickly dropping it into a vacuum suction port. Further, Patent Document 3 discloses a degassing apparatus including a vacuum suction unit that is switched on and off periodically according to increase or decrease of the degree of vacuum, when the switching cycle deviates from within a reference time. A technique is disclosed that issues a warning upon determining that an abnormality has occurred.

Japanese Patent Application Laid-Open No. 9-85011 JP 2007-152182 A JP, 2010-58413, A

  However, in these conventional techniques, it takes time to measure the amount of change in pressure and the integrated value of the amount of ink leakage, and there is a problem that the ink leakage can not be detected promptly.

  An object of the present invention is to provide a degassing apparatus and an inkjet recording apparatus capable of detecting an ink leak more quickly.

In order to achieve the above object, the invention according to claim 1 is
A gas permeable degassing film which is provided in the middle of the ink flow path and one surface of which is in contact with the ink in the ink flow path;
A vacuum suction unit,
The vacuum suction portion is connected to the surface opposite to the one surface of the degassing film, and the ink is desorbed from the ink according to the suction operation of the vacuum suction portion and desorbed after passing through the degassing film A vacuum path through which the gas flows,
A detector configured to detect transmitted light after light incident on the vacuum path is transmitted through the vacuum path;
A detection control unit that detects ink leakage from the degassing film based on a comparison result of the amount of transmitted light by the detection unit and a predetermined reference value;
It is a degassing device characterized by including.

The invention according to claim 2 is the degassing apparatus according to claim 1.
The air communication switching unit is provided in the middle of the vacuum path and switches an air communication state between the inside and the outside of the vacuum path.
The detection control unit changes the atmosphere communication switching unit to an open state when the atmosphere communication state is a closed state and the detection unit detects a transmitted light amount equal to or less than a predetermined reference value, and the change after the change It is characterized in that the ink leakage is judged based on the comparison result of the transmitted light amount by the detection unit and the predetermined reference value.

The invention according to claim 3 is the degassing apparatus according to claim 1.
A communication switching unit is provided in the middle of the vacuum path closer to the vacuum suction unit than the detection unit to open and close the flow of the desorbed gas in the vacuum path,
The detection control unit changes the flow of the desorbed gas to the closed state by the communication switching unit when the flow of the desorbed gas is open and the detection unit detects the transmitted light amount equal to or less than a predetermined reference value. It is characterized in that the ink leakage is judged based on the comparison result of the transmitted light amount by the detection unit after the change and the predetermined reference value.

The invention according to claim 4 is the deaerator according to claim 2 or 3.
The detection control unit is characterized in that ink leakage is determined based on a comparison result of the amount of transmitted light by the detection unit after a predetermined time has elapsed after the change and the predetermined reference value.

The invention according to claim 5 is the deaerator according to claim 4.
The predetermined time is less than one second.

The invention according to claim 6 is the deaerator according to any one of claims 1 to 5,
The detection unit includes a light emitting unit that causes light of a predetermined wavelength to enter the vacuum path, and a light receiving unit that receives the transmitted light after the incident light passes through at least a part of the vacuum path. It is characterized by

The invention according to claim 7 relates to the deaerator according to claim 6.
The light emitting unit is characterized in that infrared light is made incident as the light of the predetermined wavelength.

The invention according to claim 8 is the degassing apparatus according to any one of claims 1 to 7,
The portion of the vacuum path through which the light passes is characterized by being provided at different positions in the vertical direction with respect to the degassing film.

The invention according to claim 9 is the degassing apparatus according to any one of claims 1 to 8,
In the middle of the vacuum path, a chamber for separating the desorbed gas and the liquid is provided,
The detection unit transmits the incident light in the vacuum path closer to the degassed film than the chamber.

The invention according to claim 10 is
The degassing device according to any one of claims 1 to 9,
A recording head provided downstream of the ink flow path for discharging the ink;
An inkjet recording apparatus comprising:

The invention according to claim 11 relates to the ink jet recording apparatus according to claim 10.
The printing apparatus may further include an operation control unit that controls an ink discharge operation of the recording head and stops the operation of the recording head when the ink leakage is detected by the detection control unit.

The invention according to claim 12 is the inkjet recording apparatus according to claim 11.
The operation control unit may stop the operation of the recording head after the end of the discharge of the ink related to the formation of the formation target image formed by the recording head at the timing when the ink leakage is detected.

The invention according to claim 13 is the inkjet recording apparatus according to claim 11 or 12.
A notification unit for performing a predetermined notification operation;
The operation control unit is characterized by causing the notification unit to perform the predetermined notification operation when stopping the operation of the recording head.

  According to the present invention, in the degassing apparatus and the inkjet recording apparatus, it is possible to detect the ink leak more quickly.

It is a schematic diagram which shows the whole structure of the inkjet recording device of embodiment of this invention. It is a figure explaining the flow path of ink. It is a figure for demonstrating the structure inside the degassing apparatus. It is a figure explaining a detection part. FIG. 2 is a block diagram showing a functional configuration of the inkjet recording apparatus. 5 is a flowchart showing a control procedure of the ink leak detection process of the first embodiment. It is a flow chart which shows a control procedure of ink leak detection processing of a 2nd embodiment.

Hereinafter, embodiments of the present invention will be described based on the drawings.
First Embodiment
FIG. 1 is a schematic view showing an entire configuration of an inkjet recording apparatus 1 according to a first embodiment of the present invention.

  The inkjet recording apparatus 1 includes a sheet feeding unit 10, an image forming unit 20, a sheet discharging unit 30, a control unit 40 (FIG. 5), an ink supply unit 50, and the like. In the inkjet recording apparatus 1, the image forming unit 20 uses the ink supplied from the ink supply unit 50 to the recording medium P transported from the paper supply unit 10 to the image forming unit 20 under the control of the control unit 40. After the image is formed, the recording medium P is discharged to the paper discharge unit 30.

  The sheet feeding unit 10 holds a recording medium P on which an image is formed, and supplies the recording medium P to the image forming unit 20 before the image formation. The paper feed unit 10 includes a paper feed tray 11 and a transport unit 12.

  The paper feed tray 11 is a plate-like member provided so as to be capable of mounting one or more recording media P thereon. The paper feed tray 11 is provided to move up and down in accordance with the amount of the recording medium P placed thereon, and is held at a position where the uppermost recording medium P is conveyed by the conveyance unit 12.

  The transport unit 12 is mounted on a transport mechanism that transports the recording medium P on the belt 123 by rotating the annular belt 123 by a plurality of (for example, two) rollers 121 and 122, and the paper feed tray 11. It has a supply unit that delivers the top recording medium P to the belt 123. The transport unit 12 transports the recording medium P delivered to the belt 123 by the supply unit as the belt 123 rotates.

  The image forming unit 20 discharges ink onto the recording medium P to form an image. The image forming unit 20 includes an image forming drum 21, a delivery unit 22, a sheet heating unit 23, a head unit 24, an irradiation unit 25, a delivery unit 26 and the like.

  The image forming drum 21 carries the recording medium P along the cylindrical outer peripheral surface, and conveys the recording medium P as it rotates. The conveyance surface of the image forming drum 21 faces the sheet heating unit 23, the head unit 24, and the irradiation unit 25, and performs processing related to image formation on the recording medium P to be conveyed.

  The delivery unit 22 is provided at a position between the transport unit 12 of the paper feed unit 10 and the image forming drum 21, and delivers the recording medium P transported by the transport unit 12 to the image forming drum 21. The delivery unit 22 is a cylindrical delivery drum for delivering the recording medium P carried by the swing arm unit 221 or the swing arm unit 221 carrying one end of the recording medium P carried by the carrying unit 12 to the image forming drum 21. The recording medium P on the transport unit 12 is picked up by the swing arm unit 221 and delivered to the delivery drum 222 by guiding the recording medium P along the outer peripheral surface of the image forming drum 21 to form an image. Deliver to drum 21.

  The sheet heating unit 23 heats the recording medium P carried on the image forming drum 21. The sheet heating unit 23 includes, for example, an infrared heater or the like, and generates heat in response to energization. The sheet heating unit 23 is provided in the vicinity of the outer peripheral surface of the image forming drum 21 and on the upstream side of the head unit 24 in the conveyance direction of the recording medium P by the rotation of the image forming drum 21. The heat generation of the sheet heating unit 23 is controlled by the control unit 40 so that the recording medium P carried on the image forming drum 21 and passing near the sheet heating unit 23 has a predetermined temperature.

The head unit 24 discharges ink to the recording medium P carried on the image forming drum 21 to form an image. The head unit 24 is provided for each of C (cyan), M (magenta), Y (yellow), and K (black). In FIG. 1, head units 24 corresponding to the respective colors Y, M, C, and K are provided in order from the upstream with respect to the conveyance direction of the recording medium P conveyed as the image forming drum 21 rotates.
The head unit 24 of the present embodiment is provided with a length (width) that covers the entire recording medium P in a direction (width direction) perpendicular to the conveyance direction of the recording medium P. That is, the ink jet recording apparatus 1 is a one-pass type line head type ink jet recording apparatus. Each head unit 24 is provided with a plurality of recording heads 24a (see FIG. 2), and on the surface facing the transport surface of the plurality of recording heads 24a, recording media at predetermined intervals in the width direction as a whole The nozzle openings are arranged across the image formable width to P.

  The irradiation unit 25 irradiates an energy ray for curing the ink (here, the ultraviolet curable ink) discharged from the head unit 24 onto the recording medium P. The irradiation part 25 has fluorescent tubes, such as a low pressure mercury lamp, for example, makes the said fluorescent tube light, and irradiates energy rays, such as an ultraviolet-ray. The irradiation unit 25 is provided in the vicinity of the outer peripheral surface of the image forming drum 21 and on the downstream side of the head unit 24 with respect to the conveyance direction of the recording medium P by the rotation of the image forming drum 21.

  As a fluorescent tube for emitting ultraviolet light, a mercury lamp having an operating pressure of about several hundred Pa to 1 MPa besides a low pressure mercury lamp, a light source usable as a germicidal lamp, a cold cathode tube, an ultraviolet laser light source, a metal halide lamp, a light emitting diode etc. Can be mentioned. Among these, a light source (for example, a light emitting diode etc.) capable of irradiating ultraviolet light with higher illuminance and consuming less power is more desirable. The energy ray is not limited to the ultraviolet ray, but may be any energy ray having the property of curing the ink according to the property of the ink, and the light source is also replaced according to the wavelength of the energy ray or the like.

  The delivery unit 26 conveys the recording medium P irradiated with the energy rays by the irradiation unit 25 from the image forming drum 21 to the paper discharge unit 30. The delivery unit 26 rotates a ring-shaped belt 263 by a plurality of (for example, two) rollers 261 and 262 to convey the recording medium P on the belt 263, and the recording medium P from the image forming drum 21. It has a cylindrical delivery drum 264 and the like for delivering to the transport mechanism. The delivery unit 26 conveys the recording medium P delivered to the belt 263 by the delivery drum 264 by the belt 263 and delivers the recording medium P to the paper discharge unit 30.

  The paper discharge unit 30 stores the recording medium P delivered from the image forming unit 20 by the delivery unit 26. The paper discharge unit 30 has a plate-like paper discharge tray 31 and the like, and places the recording medium P after image formation on the paper discharge tray 31.

  The control unit 40 controls the operation of each unit of the inkjet recording apparatus 1 and controls the overall operation. The control unit 40 includes a central processing unit (CPU) 401, a read only memory (ROM) 402, a random access memory (RAM) 403, and the like (see FIG. 5). In the control unit 40, the program read from the ROM 402 by the CPU 401 is executed on the RAM 403, and various control processes are executed. As described later, the control unit 40 configures a detection control unit 40a related to the detection of the ink leakage and an operation control unit 40b related to the operation control of each part of the inkjet recording apparatus 1 at the time of the ink leakage detection.

  The ink supply unit 50 stores the ink and supplies the ink to the head unit 24 of the image forming unit 20. The ink supply unit 50 is provided for the ink of each color, and can discharge the ink of each color from a plurality of nozzle openings arranged in each recording head 24 a of the corresponding head unit 24.

  The ink used in the inkjet recording apparatus 1 of the present embodiment is not particularly limited, but here, as described above, it is an ultraviolet (UV) curable ink, and in the state where UV is not irradiated, the ink is used according to the temperature. It is an ink that undergoes a phase change between the gel state and the liquid (sol) state. For example, this ink has a predetermined temperature, for example, a phase change temperature of about 40 degrees to 100 degrees, and is uniformly liquefied (solified) by being heated and raised above the phase change temperature. The gelation occurs at or below the predetermined temperature including room temperature (0 degrees to 30 degrees). This ink can be obtained by various known manufacturing methods. Alternatively, the ink may be kept liquid over the entire use temperature.

  FIG. 2 is a view for explaining the flow path of the ink in the inkjet recording apparatus 1 of the present embodiment.

  In the inkjet recording apparatus 1 according to the present embodiment, the ink of each color pumped out from the ink tank 51 of the ink supply unit 50 by the supply pump 52 is transferred to the corresponding recording head 24 a of the corresponding head unit 24 via the ink flow path 24 b. Supplied to Further, the ink jet recording apparatus 1 is configured to be capable of returning the ink not ejected by each recording head 24 a to the ink flow path 24 b.

  The ink flow path 24b is provided with a second sub tank 241, a degassing module 242, a liquid feed pump 243, a check valve 244, a first sub tank 245, and the like. These are connected in order by, but not limited to, a hollow circular tube structure (liquid transfer tube). Further, the ink not ejected from the nozzle opening of the recording head 24a is returned from the outlet 240b to the second sub tank 241 through the recovery path 241b and the valve 241c. When it is necessary to remove the ink from the recording head 24a at the time of maintenance of the recording head 24a or the like, it is possible to collect the ink of the recording head 24a without wasting it by opening the valve 241c.

  The second sub tank 241 is one or more ink chambers for storing the ink pumped out of the ink tank 51 by the supply pump 52. The volume of the second sub tank 241 is usually smaller than the ink tank 51. The ink to be ejected is heated in the ink heating unit 27 by the ink heater until it is stored in the second sub tank 241 and sent to the nozzle by the recording head 24a, and it is in a solified state or a liquid having an appropriate viscosity. Maintained by

  The degassing module 242 performs degassing to remove the gas in the ink flowing from the second sub tank 241. The degassed ink is sent to the first sub tank 245 through the check valve 244 by the liquid feed pump 243.

  The liquid feed pump 243 sends the ink degassed by the degassing module 242 to the first sub tank 245. A check valve 244 provided between the liquid feed pump 243 and the first sub tank 245 prevents the ink sent to the first sub tank 245 from flowing back.

  The first sub tank 245 is a small ink chamber in which the ink degassed by the degassing module 242 is temporarily stored, and is not particularly limited, but has a capacity substantially the same as that of the second sub tank 241. is there. The first sub tank 245 is connected to the inlet 240 a of each recording head 24 a by a liquid transfer tube, and supplies the recording head 24 a with ink according to the amount of ink ejected from the nozzle opening of each recording head 24 a.

On the other hand, the degassing module 242 is connected to the atmosphere communication unit 2470 (atmosphere communication switching unit), the communication switching unit 2471, the chamber 248, and the vacuum suction unit 249. A vacuum tube 24c1 is connected between them to form a vacuum path from the degassing module 242 to the vacuum suction unit 249. The suction operation of the vacuum suction unit 249 removes the gas from the ink in the degassing module 242, and the removed gas (desorbed gas) flows through the vacuum path. A detection unit 246 is provided in a tube connecting the degassing module 242 and the atmosphere communication unit 2470 and the chamber 248. The vacuum suction unit 249 does not necessarily need to bring the inside of the vacuum path to an ultra-high vacuum state, and performs a pressure reduction to a degree necessary for degassing.
The degassing module 24c includes the degassing module 242, the detection unit 246, the atmosphere communication unit 2470, the communication switching unit 2471, the chamber 248, the vacuum suction unit 249 and the vacuum tube 24c1, and the control unit 40 (not shown in FIG. 2). It is configured.

  The atmosphere communication unit 2470 is a valve (atmospheric communication valve) whose atmosphere communication state is switched by the opening and closing operation, and the inside of the degassing device sucked by the vacuum suction unit 249 by being opened (opened). Communicate with the outside (atmosphere). Further, the communication switching unit 2471 is a communication valve that opens and closes the flow of gas or liquid flowing from the degassing module 242 to the vacuum suction unit 249 by the opening / closing operation. By closing the flow by the communication switching unit 2471, the degassing module 242 and the vacuum suction unit 249 are separated, and the flow of gas or liquid is stopped. For example, an electromagnetic valve is used for the air communication unit 2470 and the communication switching unit 2471, and the opening / closing operation can be automatically controlled by the control unit 40 and performed by the communication unit driving unit 247a (see FIG. 5). ing.

  The chamber 248 separates the ink from the gas when not only the gas but also the ink (liquid) is drawn from the degassing module 242 and flows into the vacuum path, and the liquid is drawn to the vacuum suction unit 249. The trap plays a role of preventing the occurrence of a defect such as destruction of the vacuum suction portion 249. The chamber 248 is, for example, in the form of a small tank, and liquid is stored at the bottom thereof. The chamber 248 is formed so as to be able to discharge the stored ink by opening a discharge hole (not shown).

  As described above, when the degassing module 242 is broken and a large amount of ink is leaked, the chamber 248 delays the time until the leaked ink reaches the vacuum suction portion 249, thereby delaying the vacuum suction portion 249. To prevent the failure of Therefore, the reservoir capacity of the ink in the chamber 248 needs to be equal to or larger than the size according to the required delay time.

  The vacuum suction unit 249 sucks and degasses the gas so that the inside of the vacuum path from the degassing module 242 to the vacuum suction unit 249 is maintained in the range of a predetermined negative pressure lower than the atmospheric pressure in the degassing device 24c. Discharge to the outside of the device 24c. The operation of the vacuum suction unit 249 is controlled by the control unit 40.

FIG. 3 is a view for explaining the internal structure cut at a plane passing through the central axis of the cylindrical degassing module 242.
In the inside of the outer shell 2421, the degassing module 242 is shaped such that a gas permeable degassing membrane 2426 consisting of a large number of hollow fiber membranes covers the periphery of the central pipe 2424. One end of the central tube 2424 is connected to the ink inlet 2422 and the other is sealed by a plug 2424 a. The outer wall of the central tube 2424 is provided with innumerable fine holes 2424 b (perforated holes), and the ink which has flowed into the central tube 2424 from the ink inlet 242 flows out to the periphery from these fine holes 2424 b and is deaerated. It passes between the membranes 2426 and flows out of the ink outlet 2423.

  The degassing membrane 2426 has a large number of hollow fine thread structures closed at one end, and the membrane surface has gas permeability. The other end of the fine yarn structure of the degassing film 2426 is connected to the gas outlet 2425, and the inside of the fine yarn structure of the degassing film 2426 is decompressed by the gas in the vacuum path being sucked by the vacuum suction unit 249. Ru. In this state, when the ink comes in contact with the film surface of the degassing film 2426 (the outer surface of the fine hollow fiber structure, one surface of the degassing film), only the gas in the ink selectively passes through the film surface. Ink is degassed. That is, by providing a large number of fine degassing films 2426, the contact area between the ink and the film surface can be expanded, and the degassing can be performed efficiently.

  In the degassing film 2426, the liquid component (mainly, monomer) of the ink may flow out to the vacuum path side reduced in pressure by the vacuum suction unit 249 together with the gas component normally. Further, the degassing film 2426 is deteriorated and the outflow amount of the ink is increased, and furthermore, when the degassing film 2426 is broken, the ink leaks to the vacuum path at a stretch.

  The detection unit 246 detects the liquid flowing in the vacuum tube 24c1 from the degassing module 242 to the chamber 248. The detection unit 246 is removed from the ink by the degassing module 242 by being provided to the side of the degassing module 242 with respect to the chamber 248 in the vacuum path, particularly to the vacuum tube 24c1 in the immediate vicinity of the degassing module 242 When a liquid (ink) is mixed with air, it quickly appears in the measurement result. Further, the position at which the detection unit 246 is provided in the vacuum tube 24c1 is different from the degassing module 242 (degassed film 2426) in the vertical direction (that is, the position coordinate about the vertical axis is different in the positive direction) (The position where the degassing module 242 is higher) and the vacuum tube 24c1 from the degassing module 242 to the position where the detection unit 246 is provided extends with a height in the vertical direction (vertical It is preferable that the arrangement does not have to be along the direction). As a result, even when suction is not performed, the ink and the components passing through the position of the detection unit 246 can easily move in the direction of gravity. The configuration and operation of the detection unit 246 will be described later.

FIG. 4 is a diagram for explaining the configuration of the detection unit 246. As shown in FIG.
Here, the arrangement with respect to the cross section of the vacuum tube 24c1 connected from the degassing module 242 to the atmosphere communication part 2470 is schematically shown.

  The detection unit 246 includes a light emitting unit 2461, a light receiving unit 2462, an amplifier 2463, a comparator 2464 and the like. The light emitting portion 2461 and the light receiving portion 2462 are respectively connected in series with appropriate resistance elements 2466 and 2467 between the applied voltage Vcc and the ground portion 2465, and provided at positions facing each other across the vacuum tube 24c1. ing.

  The light emitting unit 2461 is, for example, an LED (Light Emitting Diode), and emits light of a predetermined wavelength at an intensity corresponding to the magnitude of the current when an operating voltage is applied and a current flows. The wavelength of this light is not particularly limited, and an electromagnetic wave having a wavelength that can be used for measuring the amount of transmitted light can be used, but for example, it can be a wavelength in the infrared region. Infrared light has little influence from external sources (disturbances), so detection of ink in the vacuum tube is possible easily and accurately. Alternatively, in the case of using visible light, the degassing devices 24c provided for the ink flow paths 24b of each color are different in consideration of the absorptivity or scattering rate of light according to the color or component of the ink. The measurement of the ink may be performed using light of a wavelength.

The light receiving unit 2462 is, for example, a phototransistor, receives light (transmitted light) emitted from the light emitting unit 2461 and transmitted through the inside of the vacuum tube, and outputs a current according to the received light amount (transmitted light amount). It is preferable that the light receiving unit 2462 has high sensitivity to the light of the light emitting unit 2461 and low sensitivity to light of other wavelength bands.
At this time, the vacuum tube 24c1 is formed of a transparent material with respect to the wavelength band of the light emitted by the light emitting unit 2461 at least between the light emitting surface of the light emitting unit 2461 and the light receiving surface of the light receiving unit 2462. Therefore, by making the amount of light emitted from the light emitting portion 2461 constant, the amount of light received by the light receiving portion 2462 changes due to a component passing through the inside of the vacuum tube 24c1, here mainly due to absorption or scattering of ink. Become.
Alternatively, the light emitting unit 2461 and the light receiving unit 2462 (or the entire detection unit 246) are integrally formed with a connector for connecting two vacuum tubes 24c1, and light emitted from the light emitting unit 2461 is a vacuum path inside the connector The light emitting surface of the light emitting portion 2461 and the light receiving surface of the light receiving portion 2462 may be embedded in the vacuum tube 24c1. As described above, when the transmitted light does not need to be transmitted through the wall surface of the vacuum tube 24c1, the material of the vacuum tube 24c1 does not have to be transparent to the transmitted light.

The amplifier 2463 amplifies the division of the applied voltage Vcc output according to the current output from the light receiving unit 2462 according to the amount of light received. That is, the larger the amount of light received (the smaller the amount of light absorbed), the higher the partial pressure to be amplified.
The comparator 2464 compares the amplified voltage with a predetermined reference voltage Vref (a voltage corresponding to a predetermined reference value for the transmitted light amount), and outputs the comparison result to the control unit 40 as an ink leakage detection signal. . The comparison result may be output to the control unit 40 after being binarized at a predetermined sampling frequency using an ADC (analog-digital converter).

  FIG. 5 is a block diagram showing the functional configuration of the inkjet recording apparatus 1.

  The inkjet recording apparatus 1 includes a control unit 40, a conveyance drive unit 41, a head drive unit 42, a communication unit 43, an operation display unit 441, a notification output unit 442, a paper heating unit 23, and an irradiation unit 25. The ink heater drive unit 27a, the supply pump 52, the second float sensor 241a, the first float sensor 245a, the liquid feed pump 243, the detection unit 246, the communication unit drive unit 247a, and the vacuum suction unit 249. And the like, and these units are connected to one another by a bus 49.

  The conveyance drive unit 41 operates each unit for conveying the recording medium P. That is, the conveyance drive unit 41 includes a rotation motor of the image forming drum 21 and a rotation drive unit of at least a part of the rollers 121, 122, 261, 262, and the like. Then, the sheet is moved to the sheet discharge unit 30.

  The head drive unit 42 ejects ink from a plurality of nozzle openings provided in the recording head 24 a of each head unit 24. For example, the head drive unit 42 applies an ink flow path by applying a predetermined voltage waveform to a pressure application mechanism (such as a piezoelectric element) provided along the ink flow path communicating with the nozzle opening in the recording head 24 a. Is deformed to apply pressure to the ink in the ink flow path, and the ink is ejected from the nozzle opening of the ink ejection target.

  The communication unit 43 is for performing communication between the inkjet recording apparatus 1 and an external device, and includes a NIC (Network Interface Card) or the like. For example, the communication unit 43 receives, from an external device, image data to be subjected to image formation and data of a print job relating to print settings of the image data, and the like. When transmitting status information such as an abnormality, processing concerning transmission and reception of the data is performed.

  The operation display unit 441 is used by the user to directly input settings and the like related to the operation of the inkjet recording apparatus 1 and to display the above-described status information. The operation display unit 441 performs various displays on the display screen according to the control signal from the control unit 40 as the display unit 441b, and a touch sensor provided overlapping the display screen as the operation detection unit 441a. The user's touch operation and its type and position are acquired to output an operation signal to the control unit 40.

The notification output unit 442 is for performing a predetermined notification operation, and for example, an audio output unit that generates a buzzer sound or a beep sound, an LED lamp that can light and blink light of a predetermined wavelength, and the like. Prepare.
A notification unit 440 is configured by the display unit 441 b and the notification output unit 442 described above.

  The ink heater drive unit 27 a operates the ink heater according to the control signal from the control unit 40 to heat the ink in the ink heating unit 27. The ink heating unit 27 is provided with one or more temperature sensors, and the control unit 40 causes the ink heater driving unit 27a to switch the on / off of the ink heater according to the temperature of the ink measured by the temperature sensor. Keep the ink at the proper temperature.

  The second float sensor 241 a and the first float sensor 245 a respectively measure the amount of ink inside the second sub tank 241 and the first sub tank 245. The control unit 40 intermittently operates the supply pump 52 and the liquid feed pump 243 so that the amounts of ink inside the second sub tank 241 and the first sub tank 245 fall within the set range.

  The communication unit drive unit 247 a opens and closes the atmosphere communication unit 2470 and the communication switching unit 2471 in accordance with the control signal from the control unit 40. The air communication unit 2470 and the communication switching unit 2471 can independently control the opening and closing operation.

  Next, the operation of the degassing device 24c and the detection of the ink leak of the degassing device 24c will be described.

  The degassing device 24c continuously discharges the vacuum suction portion 249 during a preparation period and a predetermined standby time after the completion of the ink ejection operation, while the ink ejection operation from the recording head 24a is being performed. The operation related to the degassing is performed by operating the. In the deaerator 24c, the operation of detecting the ink leak is performed over the operation period of the vacuum suction unit 249 and the time after the operation is completed until the pressure reduction state in the vacuum path is canceled. Alternatively, even during the stop period of the vacuum suction unit 249, the ink leaks over the period during which the power supply of the inkjet recording apparatus 1 is turned on, except when operating in a special operation mode related to abnormality occurrence or maintenance. The detection operation may be continued.

  In the inkjet recording apparatus 1 according to the present embodiment, the light receiving amount measurement of the light receiving unit 2462 in the detecting unit 246 is continuously performed, and the comparison result of the voltage value corresponding to the light receiving amount and the preset reference voltage is obtained. When the light reception amount decreases and the voltage value decreases and becomes lower than the reference voltage, detection is performed based on the output of the comparator 2464. In addition, when it is detected that the voltage value corresponding to the amount of light received has become equal to or lower than the reference voltage, the pressure in the vacuum tube is raised to perform suction to determine whether the detection is due to ink leakage. After the suspension, the detection operation is performed again, and it is determined that the ink leakage is detected when the voltage value lower than the reference voltage is continuously detected. The reference voltage is appropriately determined according to the color and type of ink, the thickness and material of the tube, and the like. That is, it may be separately determined for each of the degassing devices 24c for the ink of each color.

  The gas permeable degassing film 2426 may transmit not only the gas but also a monomer which is an ink or a component of the ink slightly even in a normal state. These components are normally not detected continuously as they do not pass continuously, and monomers are difficult to detect when the aspiration is stopped and the movement in the vacuum tube 24c1 ceases. Therefore, by performing detection again after the operation of the air communication unit 2470 and the communication switching unit 2471, detection of the reference voltage or less due to such temporary transmission of the ink component is excluded from the detection of ink leakage.

At this time, the time interval of the first detection and re-detection is out of the detection position due to non-continuous ink or monomer falling (flows down) in the vertical direction by communicating with the atmosphere, and is almost stopped and not detected. It is a time longer than the time required to change the thickness of the tube, and changes depending on the thickness of the tube, the variation in the amount of permeated ink and monomer, and the viscosity, but usually it may be short (for example, less than 1 second). It is 100 to 500 msec. In addition, such commands may be sequentially executed without appropriately setting the timing.
In addition, although detection is performed twice separately here, detection is continuously performed and determination of ink leakage is performed based on a change in comparison result between the transmitted light amount and the reference value during the detection period. Also good.

FIG. 6 is a flowchart showing a control procedure by the control unit 40 of the ink leak detection process executed by the inkjet recording apparatus 1 according to the first embodiment.
The ink leak detection process is started at the same time as the main power supply of the inkjet recording apparatus 1 is turned on.

  When the ink leak detection process is started, the control unit 40 (CPU 401) causes the light emitting unit 2461 of the detection unit 246 to emit light, and causes the light receiving unit 2462 to start detecting the amount of transmitted light (step S101). The light emitting operation of the light emitting unit 2461 can be continuously performed while the ink leak detection process is continued thereafter.

  Next, the control unit 40 as the detection control unit 40a acquires the comparison result of the measured voltage and the reference voltage compared by the comparator 2464 (step S102). The control unit 40 as the detection control unit 40a determines whether the measured value is less than or equal to a predetermined reference value (step S103). If it is determined that the pressure is not less than the predetermined reference value ("NO" in step S103), it is considered that there is no liquid component that absorbs incident light in the vacuum tube, and the process of the control unit 40 proceeds to step S102. Return. If it is determined that the value is equal to or less than the predetermined reference value ("YES" in step S103), the control unit 40 as the detection control unit 40a sends a control signal to the communication unit drive unit 247a. It is opened (step S104).

  The control unit 40 determines whether a predetermined time has elapsed (step S106), and repeats the process of step S106 while it is determined that the predetermined time has not elapsed ("NO" in step S106). When it is determined that the predetermined time has elapsed ("YES" in step S106), the control unit 40 as the detection control unit 40a acquires the comparison result of the measurement value and the reference value again from the detection unit 246 (step S106). And determine whether the measured value is less than or equal to the reference value (step S107).

  If it is determined that the measured value is not below the reference value ("NO" in step S107), there is no liquid component in the vacuum tube, or the previous detection is due to a temporarily detected monomer component or the like The control unit 40 outputs a control signal to the communication unit drive unit 247a to close the air communication unit 2470 (step S108), thereby returning the inside of the vacuum tube to a normal vacuum suction state. Then, the process of the control unit 40 returns to step S102.

If it is determined that the measured value is less than or equal to the reference value ("YES" in step S107), it is considered that abnormal ink leakage has occurred in the vacuum tube, that is, the first detection is the degassing film This is due to breakage of 2426 or the like, and the control unit 40 as the operation control unit 40b cancels the image formation (step S109), and performs a predetermined operation of reporting an abnormality related to the ink leakage (step S110). The control unit 40 as the operation control unit 40b causes the display screen of the operation display unit 441, for example, to perform a display indicating abnormality as a predetermined operation. Alternatively, when the notification output unit 442 includes an audio output unit, the control unit 40 may output a beep or the like, and when the notification output unit 442 includes an LED lamp or the like. The LED lamp may be lit or blinked. Furthermore, at this time, the control unit 40 may store the stop date and time, the reason, and the like in a log or the like.
Further, at this time, the control unit 40 as the operation control unit 40 b causes the image forming unit 20 to start forming an image of the image to be formed (one recording medium or one repetitive image forming operation). After the completion of the ink ejection for the sheet etc.), the image forming process is stopped.
Then, the control unit 40 ends the ink leak detection process.

As described above, the degassing device 24c included in the inkjet recording apparatus 1 according to the present embodiment is provided in the middle of the ink flow path 24b, and the hollow fiber membrane degassing is performed with the outer surface contacting the ink in the ink flow path 24b. The membrane 2426, the vacuum suction portion 249, the inner surface side of the hollow fiber membrane degassing membrane 2426 and the vacuum suction portion 249 are connected, and the ink is detached from the ink according to the suction operation of the vacuum suction portion 249 A vacuum path through which desorbed gas that has passed through 2426 flows, and a detection unit 246 that detects transmitted light after light incident in the middle of the vacuum path passes through the vacuum path, a transmitted light amount by the detection unit 246 and a predetermined amount. And a control unit 40 as a detection control unit 40a that detects ink leakage based on a comparison result with a reference value.
That is, since the ink passing through the vacuum path (vacuum tube 24c1) can be measured in substantially real time, the ink leakage can be detected promptly.

  In addition, an atmosphere communication unit 2470 is provided in the middle of the vacuum path to switch the atmosphere communication state between the inside and the outside (atmosphere) of the vacuum path, and the atmosphere communication state is closed and the predetermined reference is set by the detection unit 246 When a measured value equal to or less than the detected value is detected, the control unit 40 as the detection control unit 40a changes the atmosphere communication unit 2470 to the open state, and after the change, the measured value related to the transmitted light amount and the predetermined reference value. The determination of the ink leakage is made based on the comparison result of Therefore, it seems that the ink is already accumulated in the vacuum path even if the vacuum path returns to normal pressure, and the temporary passage of the monomer and the trace ink component etc. which detection stops when the vacuum path returns to normal pressure. It is possible to detect the ink leakage due to the damage of the degassing film 2426 or the like and to detect it quickly and more reliably.

  Further, after the control unit 40 as the detection control unit 40a changes the atmosphere communication unit 2470 from the closed state to the open state, the comparison result of the measurement value related to the transmitted light quantity by the detection unit 246 after a predetermined time elapses and the reference value. Make an ink leak determination based on Therefore, the presence or absence of the ink leakage can be determined easily and promptly based on the second detection result.

  In addition, by setting the predetermined time between the first detection and the second detection to less than one second, it is possible to quickly detect the ink leakage immediately after the occurrence of the ink leakage.

  The detection unit 246 further includes a light emitting unit 2461 for causing light of a predetermined wavelength to enter the vacuum path, and a light receiving unit 2462 for receiving the transmitted light after the incident light passes through at least a part of the vacuum path. Prepare. Therefore, the measurement of the ink can be performed with high accuracy by causing the light having an appropriate amount of light to be incident without unevenness.

  In addition, since the light emitting unit 2461 allows infrared light to be incident as light of a predetermined wavelength, it is possible to perform measurement of the ink which is less susceptible to disturbance and accurate.

  In addition, since the portion through which light emitted from the light emitting unit 2461 in the vacuum path is transmitted is provided at a position lower in the vertical direction than the degassing film 2426 of the degassing module 242, the ink leaked in the degassing module 242 The component is pulled by gravity and passes the detection position by the detection unit 246 promptly. Therefore, it is possible to suppress an increase in time lag from ink leakage to detection.

  Further, a chamber 248 for separating the desorbed gas and the ink (liquid) is provided in the middle of the vacuum path, and the detection unit 246 is incident in the vacuum path on the side of the degassing module 242 rather than the chamber 248. Since light is transmitted, it is possible to prevent the leaked ink from being trapped in the chamber 248 and delayed in detection.

  Further, the inkjet recording apparatus 1 of the present embodiment includes the degassing device 24c, and the recording head 24a provided on the downstream side of the ink flow path 24b and discharging the ink. Therefore, in the ink jet recording apparatus 1, it is possible to promptly detect and cope with the ink discharge and, consequently, the ink leakage in the deaerator 24c which adversely affects the formed image.

  The control unit 40 as the operation control unit 40b stops the operation of the recording head 24a when the ink leakage is detected. That is, by stopping the image formation promptly before the deterioration of the image caused by the ink leakage detected promptly, the generation of the useless recording medium and the ink can be prevented.

  Further, the control unit 40 as the operation control unit 40b stops the operation of the recording head 24a after the completion of the discharge of the ink related to the formation of the formation target image formed by the recording head 24a at the timing when the ink leakage is detected. Therefore, the image in the process of formation is completed while effectively utilizing the ink that has already been degassed on the downstream side of the degassing device 24c, so that an image having a deteriorated image quality is not newly formed, and Do not waste the recording medium or the ejected ink.

  In addition, the control unit 40 as the operation control unit 40b performs a predetermined display on the display screen of the operation display unit 441 when the operation control unit 40b stops the operation of the recording head 24a. A predetermined notification operation for notifying an abnormality is performed. Therefore, the user of the ink jet recording apparatus 1 can be promptly informed of the cause of the discontinuation, and prompt action can be taken.

Second Embodiment
Next, an ink jet recording apparatus according to a second embodiment will be described.
The configuration of the inkjet recording apparatus 1 is the same as that of the inkjet recording apparatus 1 of the first embodiment, and the description will be omitted as the same reference numerals are used.

  Next, the ink leak detection operation in the inkjet recording apparatus 1 of the present embodiment will be described.

  FIG. 7 is a flowchart showing a control procedure by the control unit 40 of the ink leak detection process executed by the inkjet recording apparatus 1 of the present embodiment. The ink leak detection process in the ink jet recording apparatus 1 according to the second embodiment is that the processes in steps S104 and S108 in the ink leak detection process in the ink jet recording apparatus 1 according to the first embodiment are replaced with steps S104 a and S108 a, respectively. The process is the same except for the same processing content, the same reference numerals are attached and the detailed description is omitted.

  If it is determined in the determination process of step S103 that the measured value is less than or equal to the reference value ("YES" in step S103), the control unit 40 as the detection control unit 40a sends a control signal to the communication unit drive unit 247a. To close the communication switching unit 2471 (step S104a).

  When it is determined in the determination process of step S107 that the measured value is not less than or equal to the reference value ("NO" in step S107), the control unit 40 as the detection control unit 40a opens the communication switching unit 2471. Then, the inside of the vacuum tube is returned to the normal vacuum suction state (step S108a). Then, the process of the control unit 40 returns to step S102.

  As described above, the inkjet recording apparatus 1 according to the second embodiment is provided in the middle of the vacuum path closer to the vacuum suction unit 249 than the detection unit 246, and opens and closes the flow of desorbed gas in the vacuum path. The control unit 40 as the detection control unit 40a includes the unit 2471. When the flow of the desorption gas is open and ink leakage is detected by the detection unit 246, the flow of the desorption gas is closed by the communication switching unit 2471. The state is changed, and the cause of the first detection is determined based on the comparison result of the transmitted light amount after the change and a predetermined reference value. Therefore, by interrupting the suction by the vacuum suction unit 249 and forcibly stopping the flow by suction, permeation of the temporary degassing film 2426 such as a monomer or a trace ink component that occurs sporadically and immediately stops detection. The ink leakage can be detected quickly and more reliably by distinguishing the ink leakage due to the breakage of the degassing film 2426 and the like.

The present invention is not limited to the above embodiment, and various modifications are possible.
For example, in the above embodiment, although the degassing device 24c includes both the air communication unit 2470 and the communication switching unit 2471, it may be one required for the second detection operation. Further, both the atmosphere communication unit 2470 and the communication switching unit 2471 may be used simultaneously for the ink leak detection process. Furthermore, the result may be determined only by the first ink leak detection, and false detection may occur as reopening after the air communication portion 2470 is opened and / or the communication switching portion 2471 is not closed. Even if it includes, the possibility of the ink leakage may be detected in a short time when the ink leakage occurs, and an abnormality notification may be performed or the image formation may be stopped.

  Although the chamber 248 is provided in the above embodiment, the vacuum tube 24c1 itself may be long, or the vacuum suction unit 249 may have a structure in which the ink is not sucked to the inside. However, the chamber 248 may not necessarily be provided. Also, the chamber 248 may be provided including spaces used for various applications as well as the application as a trap.

  In the above embodiment, although the degassing apparatus using the hollow fiber membrane as the degassing membrane 2426 has been described as an example, it is a degassing apparatus using a gas permeable degassing membrane having other shapes. Also good.

  Further, in the above embodiment, although the detection unit 246 compares the measured value with the reference voltage Vref and outputs only the comparison result, the control unit 40 acquires the measured value and the CPU 401 performs a software operation. The control unit 40 may perform part of the operation as the detection unit by comparing with the reference voltage Vref.

  In the above embodiment, the control unit 40 (CPU 401) of the inkjet recording apparatus 1 performs the control operation of the ink leak detection process, but the deaerator 24c separately includes a control unit to perform the control operation. The configuration may be such that an operation request related to the cancellation or notification of the image formation is output to the control unit 40 as necessary. Alternatively, the control unit of the deaerator 24c may perform the operation as the detection control unit 40a, and the control unit 40 may perform the operation as the operation control unit 40b.

  In addition, the length, shape, material, and the like of the vacuum tube forming the vacuum path may be appropriately selected as long as measurement of the amount of transmitted light is possible. Similarly, in the detection unit 246, the configuration and the circuit arrangement may be arbitrarily determined as long as the transmitted light can be detected.

In the above embodiment, when the ink leakage is detected, the discharge of the ink is continued until the formation target image being formed is formed. However, the discharge of the ink may be stopped immediately. The determination may be made according to the remaining amount of. Further, the image to be formed is not limited to one cut sheet, etc., and may be one unit of an image repeatedly formed in the cut sheet, or, conversely, a set of a plurality of sheets. good. In addition, when an image is formed on continuous paper, a continuous cloth, or the like, the discharge of the ink may be appropriately ended at the break of the image.
In addition, specific details such as the configuration, arrangement, and operation procedure described in the above embodiment can be appropriately changed without departing from the spirit of the present invention.

  The present invention can be used for a degassing apparatus and an inkjet recording apparatus.

Reference Signs List 1 inkjet recording apparatus 10 sheet feeding unit 11 sheet feeding tray 12 conveying unit 121, 122 roller 123 belt 20 image forming unit 21 image forming unit 22 image forming drum 22 delivery unit 221 swing arm unit 222 delivery drum 23 sheet heating unit 24 head unit 24a recording head 240a Inlet 240b Outlet 24b Ink channel 241 Second sub-tank 241a Second float sensor 241b Collection channel 241c Valve 242 Degassing module 2421 Outer shell 2422 Ink inlet 2423 Ink outlet 2424 Center tube 2424a Plug 2424b Narrow hole 2425 Gas outlet 2426 Air film 243 Liquid feed pump 244 Check valve 245 1st sub tank 245a 1st float sensor 24c Deaerator 246 Detection part 2461 Light emitting part 2462 Light reception 2463 Amplifier 2464 Comparator 2465 Grounding part 2466, 2467 Resistance element 247a Communication part drive part 2470 Atmospheric communication part 2471 Communication switching part 248 Chamber 249 Vacuum suction part 24c1 Vacuum tube 25 Irradiation part 26 Delivery part 261, 262 Roller 263 Belt 264 Delivery drum 27 Ink heating unit 27a Ink heater drive unit 30 Discharge unit 31 Discharge tray 40 Control unit 40a Detection control unit 40b Operation control unit 401 CPU
402 ROM
403 RAM
41 transport drive unit 42 head drive unit 43 communication unit 440 notification unit 441 operation display unit 441a operation detection unit 441b display unit 442 notification output unit 49 bus 50 ink supply unit 51 ink tank 52 supply pump P recording medium Vcc applied voltage Vref reference voltage

Claims (13)

A gas permeable degassing film which is provided in the middle of the ink flow path and one surface of which is in contact with the ink in the ink flow path;
A vacuum suction unit,
The vacuum suction portion is connected to the surface opposite to the one surface of the degassing film, and the ink is desorbed from the ink according to the suction operation of the vacuum suction portion and desorbed after passing through the degassing film A vacuum path through which the gas flows,
A detector configured to detect transmitted light after light incident on the vacuum path is transmitted through the vacuum path;
A detection control unit that detects ink leakage from the degassing film based on a comparison result of the amount of transmitted light by the detection unit and a predetermined reference value;
A degassing device comprising: The air communication switching unit is provided in the middle of the vacuum path and switches an air communication state between the inside and the outside of the vacuum path.
The detection control unit changes the atmosphere communication switching unit to an open state when the atmosphere communication state is a closed state and the detection unit detects a transmitted light amount equal to or less than a predetermined reference value, and the change after the change The degassing apparatus according to claim 1, wherein the ink leakage is determined based on a comparison result of the transmitted light amount by the detection unit and the predetermined reference value. A communication switching unit is provided in the middle of the vacuum path closer to the vacuum suction unit than the detection unit to open and close the flow of the desorbed gas in the vacuum path,
The detection control unit changes the flow of the desorbed gas to the closed state by the communication switching unit when the flow of the desorbed gas is open and the detection unit detects the transmitted light amount equal to or less than a predetermined reference value. The degassing apparatus according to claim 1, wherein the ink leakage is determined based on a comparison result of the transmitted light amount by the detection unit after the change and the predetermined reference value.   3. The apparatus according to claim 2, wherein the detection control unit determines the ink leakage based on a comparison result of the amount of transmitted light by the detection unit after a predetermined time after the change and the predetermined reference value. 3. The degassing device according to 3.   The degassing apparatus according to claim 4, wherein the predetermined time is less than one second.   The detection unit includes a light emitting unit that causes light of a predetermined wavelength to enter the vacuum path, and a light receiving unit that receives the transmitted light after the incident light passes through at least a part of the vacuum path. The degassing apparatus as described in any one of the Claims 1-5 characterized by the above-mentioned.   The degassing apparatus according to claim 6, wherein the light emitting unit causes infrared light to be incident as the light of the predetermined wavelength.   The degassing apparatus according to any one of claims 1 to 7, wherein the portion of the vacuum path through which light is transmitted is provided at a position different from the degassing film in the vertical direction. . In the middle of the vacuum path, a chamber for separating the desorbed gas and the liquid is provided,
The degassing apparatus according to any one of claims 1 to 8, wherein the detection unit transmits the incident light in the vacuum path closer to the degassing membrane than the chamber. The degassing device according to any one of claims 1 to 9,
A recording head provided downstream of the ink flow path for discharging the ink;
An inkjet recording apparatus comprising:   The ink jet recording apparatus according to claim 10, further comprising an operation control unit configured to control an ink discharge operation in the recording head and to stop the operation of the recording head when the ink leakage is detected by the detection control unit. Recording device. The operation control unit may stop the operation of the recording head after the completion of the discharge of the ink related to the formation of the formation target image formed by the recording head at the timing when the ink leakage is detected. Item 12. An ink jet recording apparatus according to item 11. A notification unit for performing a predetermined notification operation;
13. The inkjet recording apparatus according to claim 11, wherein the operation control unit causes the notification unit to perform the predetermined notification operation when stopping the operation of the recording head.

Images