JP2006021380A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer which can surely grasp a refilling time of ink by simply and suitably sensing the fact when there is no residual quantity of ink in an ink tank. <P>SOLUTION: A damper 12 for temporarily storing the ink is set in the halfway of an ink supply pipe 9a which supplies the ink from a main tank 11 to a recording head 7. A liquid sending pump 23 for sending the ink to the damper 12 is set between the main tank 11 and the damper 12. Moreover, a control part 25 is set for sending the ink from the main tank 11 to the damper 12 by actuating the liquid sending pump 23 when it is sensed by a membrane level sensor 19 for sensing the ink residual quantity in the damper 12 that the ink residual quantity in the damper 12 is not larger than a predetermined quantity. If the ink residual quantity in the damper 12 is not increased even when the liquid sending pump 23 is actuated, the control part 25 judges that there is no ink residual quantity in the main tank 11 and makes the fact informed by a display part 28. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet printer, and more particularly to an ink jet printer that performs image recording using high-viscosity ink.

  In general, ink jet printers are known as means capable of printing on various recording media. Ink jet printers, for example, use a piezo element or a heater to eject ink from the nozzles of the recording head as fine droplets toward a recording medium such as paper, and then adjust the recording head while penetrating or fixing the ink to the recording medium. Since the image is recorded on the recording medium by moving it on the recording medium, there is an advantage that printing according to demand is possible because a plate making process is not required. In particular, in recent years, inkjet printers using a photocurable ink that is cured by light such as ultraviolet rays have been known. According to this, ink is cured by irradiating the ink landed on the recording medium with light. Since the image can be fixed on the recording medium, printing can be easily performed even on a recording medium that does not absorb ink, such as a transparent or translucent resin film.

  Such an ink jet printer generally performs image recording while supplying ink from an ink tank that stores ink to the recording head as needed, but the amount of ink stored in the ink tank is increased as the image recording operation is repeated. It will decrease. For this reason, in order to perform the image recording operation continuously and smoothly, it is necessary to appropriately grasp the remaining amount of ink in the ink tank and appropriately replenish ink when there is no remaining amount of ink.

Therefore, conventionally, a means for detecting the remaining amount of ink by detecting a change in the weight of the ink tank by providing a weight sensor in the ink tank, or counting the amount of ink ejected during image recording, and the counted ink amount Is subtracted from the total amount of ink in the ink tank to calculate the remaining amount of ink in the ink tank (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-248917

  However, the ink tank has various parts such as an outer case for ink and a member for joint. For this reason, the means for providing a weight sensor in the ink tank detects the weight of these parts in addition to the ink in the ink tank when the weight of the ink in the ink tank is to be detected. There was a problem that could not be done. In addition, in an ink jet printer, ink discharge may occur due to an abnormal discharge due to a missing nozzle or the like, or when the recording head is cleaned, ink is forcibly sucked from the nozzle or is ejected idle. is there. However, the means for counting the amount of ink ejected at the time of image recording does not count such outflow of ink, and the amount of ink that flows out during ejection abnormality or cleaning must be managed with high accuracy. Is difficult to accurately grasp the remaining amount of ink.

  Accordingly, the present invention has been made to solve the above-described problems, and when there is no remaining ink in the ink tank, this is easily and appropriately detected to accurately grasp the ink replenishment timing. An object of the present invention is to provide an ink jet printer capable of performing the above.

In order to solve such a problem, the invention described in claim 1 includes an ink tank that stores ink, a recording head that discharges ink, and an ink supply that supplies ink from the ink tank to the recording head. With a tube,
A damper that temporarily stores ink is provided in the middle of the ink supply pipe, and a liquid feed pump that supplies ink to the damper is provided between the ink tank and the damper.
A remaining amount detecting means for detecting the remaining amount of ink in the damper, an informing means for notifying when there is no remaining ink in the ink tank, and the remaining amount detecting means is a remaining amount of ink in the damper. A controller for controlling the liquid feed pump so as to feed the ink in the ink tank to the damper when it is detected that the amount is equal to or less than a predetermined amount;
When the remaining amount detecting means does not detect an increase in the remaining amount of ink in the damper even when the liquid feeding pump is operated, the control unit determines that there is no remaining ink in the ink tank, and This is characterized in that the notification means notifies the fact.

  In the invention according to claim 1 having such a configuration, when the remaining amount of ink in a damper provided in the middle of the ink supply pipe is detected by the remaining amount detecting means, and the remaining amount of ink is less than a predetermined amount, The control unit controls the liquid supply pump to supply the ink in the ink tank to the damper. When the remaining amount detecting means does not detect that the remaining amount of ink in the damper has increased even when the liquid feed pump is operated, the notifying means notifies that there is no remaining ink in the ink tank. ing.

  According to a second aspect of the present invention, in the ink jet printer according to the first aspect, the damper includes an ink chamber for storing ink, and a flexible damper film is provided on at least one surface of the ink chamber. In addition, an elastic member for holding the damper film at a predetermined initial position is provided.

  According to the second aspect of the present invention having such a configuration, the damper film provided on one surface of the ink chamber in the damper is bent to absorb the ink pressure fluctuation caused by the inflow and outflow of the ink. In addition, the damper film is held at a predetermined initial position by an elastic member to keep the ink chamber in a negative pressure state.

  According to a third aspect of the present invention, in the ink jet printer according to the first or second aspect, the remaining amount detecting means is a photo sensor for detecting the position of the damper film or the pressure of ink flowing out of the damper. It is the pressure sensor which detects this.

  The invention according to claim 3 having such a configuration is configured to detect whether or not a predetermined amount of ink remains in the damper by a photo sensor or a pressure sensor.

  According to a fourth aspect of the present invention, in the inkjet printer according to any one of the first to third aspects, the recording head heats ink that is a liquid having a viscosity of 10 to 500 mPa · s at 30 ° C. It is characterized in that it is heated to 30 to 150 ° C. by means and discharged so that one dot becomes a small droplet of 2 to 20 pl.

  In the invention according to claim 4 having such a configuration, image recording is performed using a high-viscosity ink having a viscosity of 10 to 500 mPa · s at 30 ° C.

  Further, according to a fifth aspect of the invention, in the ink jet printer according to any one of the first to fourth aspects, the ink is a photocurable ink that cures when irradiated with light, and the recording head In addition, a light irradiating device for irradiating light onto the ink landed on the recording medium is provided on the downstream side in the transport direction of the recording medium.

  As described above, in the invention described in claim 5, the ink is cured and fixed on the recording medium by irradiating the ink ejected from the recording head with light.

  Next, according to a sixth aspect of the present invention, in the ink jet printer according to the fifth aspect, the ink is an ultraviolet curable ink that is cured by irradiating ultraviolet rays, and the light irradiated from the light irradiation device. Among these, at least a part is ultraviolet rays.

  Therefore, in the invention described in claim 6, the ink ejected from the recording head is irradiated with ultraviolet rays so that the ink is cured and fixed on the recording medium.

  Next, according to a seventh aspect of the present invention, in the ink jet printer according to any one of the first to sixth aspects, the ink is a high-viscosity ink and is a cationic polymerization type ultraviolet curable ink. It is characterized by.

  According to the seventh aspect of the present invention, image recording is performed using a high viscosity ink, in particular, a cationic polymerization type ultraviolet curable ink mainly composed of a monomer.

  The invention according to claim 8 is the ink jet printer according to any one of claims 1 to 7, wherein the recording medium has no ink absorptivity.

  According to the eighth aspect of the invention, image recording is performed on a recording medium having no ink absorbability such as resin.

  According to the first aspect of the present invention, it is possible to determine whether or not there is an ink remaining amount in the ink tank by detecting whether or not the damper is replenished with ink. Unlike the case of detecting directly, it is not influenced by other elements such as ink tank parts. In addition, unlike the case of counting the printing amount or the like, it is possible to detect a decrease in the ink amount due to the outflow of ink other than image recording. For this reason, it is possible to accurately grasp the replenishment timing of the ink in the ink tank, and it is possible to perform a stable image recording operation by appropriately replenishing ink even when continuous image recording is performed. . Furthermore, when there is no ink remaining in the ink tank, the notification means notifies the user, so that the user can surely know that there is no ink remaining and can replenish ink appropriately. .

  According to the second aspect of the invention, by forming a part of the ink chamber of the damper with the flexible damper film, the damper absorbs the ink pressure fluctuation caused by the inflow and outflow of the ink. Can do. Further, since the damper film is held at a predetermined initial position by the elastic member, when the ink in the damper decreases, the elastic member pushes back the damper film to be bent to the inside of the damper. A constant negative pressure state can be maintained inside. For this reason, the ink can be stably ejected from the recording head regardless of the inflow and outflow of ink, and the ink can be prevented from leaking from the recording head other than during image recording.

  According to the invention described in claim 3, it is possible to detect whether or not a predetermined amount of ink remains in the damper with a simple configuration of a photo sensor or a pressure sensor. For this reason, it is possible to grasp the remaining amount of ink in the damper without complicating and increasing the size of the damper, and it is effective in reducing the size and weight of the apparatus.

  Next, according to the invention described in claim 4, since the high-viscosity ink having a viscosity of 10 to 500 mPa · s at 30 ° C. is used, the recording medium P can be used even for the recording medium P having no ink absorbability. It is possible to record high-quality images without causing ink flow or the like above, and even when using such highly viscous ink, ink is smoothly discharged with reduced ink pressure loss. In addition, when there is no ink remaining in the ink tank, it is possible to easily detect that fact.

  Further, since the ink is heated to 30 to 150 ° C. and discharged from the recording head, it is possible to perform image recording while maintaining good ink discharge from the nozzle, and further, the ink is 2 to 20 pl per dot. Since the liquid droplets are ejected in small droplets, a high-quality image can be obtained even with high viscosity ink. Even in such a case, the ink pressure loss can be reduced and ink can be ejected smoothly, and when there is no ink remaining in the ink tank, it can be easily detected. Play.

  According to the invention described in claim 5, since the ink is cured by irradiating the ink with ultraviolet rays, it is possible to form an image even on a recording medium having poor ink absorption such as a resin film. However, even in such a case, the ink pressure loss can be reduced and the ink can be ejected smoothly, and when there is no ink remaining in the ink tank, it can be easily detected. There is an effect.

  According to the invention described in claim 6, since the ink is cured by irradiating the ink with ultraviolet rays, it is possible to form an image even on a recording medium having poor ink absorbability such as a resin film. However, even in such a case, the ink pressure loss can be reduced and the ink can be ejected smoothly, and when there is no ink remaining in the ink tank, it can be easily detected. There is an effect.

  Further, according to the invention described in claim 7, even when a high-viscosity ink is used, and particularly when a cationic ultraviolet curable ink mainly composed of a monomer is used, the pressure loss of the ink is reduced. Ink can be ejected smoothly, and when there is no ink remaining in the ink tank, the effect can be easily detected.

  According to the eighth aspect of the present invention, high-viscosity ink is used to prevent ink from flowing on the recording medium even when an image is recorded on a recording medium such as a resin that does not absorb ink. Even in such a case, the ink pressure loss can be reduced and ink can be ejected smoothly, and when there is no ink remaining in the ink tank, it is easily detected. There is an effect that can be.

  Hereinafter, a first embodiment of an ink jet printer according to the present invention will be described with reference to the accompanying drawings.

  First, as shown in FIG. 1, in this embodiment, the ink jet printer 1 is an ink jet printer 1 of a serial printing system, and the ink jet printer 1 is formed in a flat plate shape and supports a recording medium P from a non-recording surface. A platen 2 is provided. Conveying rollers 3 and 4 for conveying the recording medium P while maintaining the substantially same height as the platen 2 are rotatably provided on the upstream side and the downstream side of the platen 2, respectively. The transport rollers 3 and 4 are rotated by the mechanism 30 (see FIG. 3) so that the transport rollers 3 and 4 are transported in the predetermined transport direction X along the upper surface of the platen 2.

  Above the platen 2, a rod-shaped guide rail 5 extending in the main scanning direction orthogonal to the conveyance direction X of the recording medium P is provided. A carriage 6 is supported on the guide rail 5, and the carriage 6 reciprocates in the main scanning direction along the guide rail 5 by a carriage driving mechanism 29 (see FIG. 3).

  A recording head 7 corresponding to each color (for example, yellow (Y), magenta (M), cyan (C), black (K)) used in the ink jet printer 1 according to the present embodiment is mounted on the carriage 6. ing. A plurality of nozzles (not shown) for ejecting ink are provided on the surface of the recording head 7 facing the recording medium P. For example, a piezo element (not shown) as a piezoelectric element that is deformed by applying a voltage is attached to the nozzle of each recording head 7, and the piezo element is deformed by applying a driving voltage to the piezo element. Thus, the ink flow path is compressed and ink is ejected from the nozzles. In addition, a heater (not shown) is provided in the ink flow path so as to heat the ink before the ink is ejected. In order to enable high-definition image recording, it is desirable that the ink is ejected as minute droplets in which one dot is 2 to 20 pl. Further, the ink used in the inkjet printer 1 is not limited to those illustrated, and for example, colors such as light yellow (LY), light magenta (LM), and light cyan (LC) can be used. In this case, the recording head 7 corresponding to each color is mounted on the carriage 6.

  The ink used in the present embodiment is a photocurable ink having a property of being cured when irradiated with ultraviolet rays as light, and has at least a polymerizable compound (including a known polymerizable compound) as a main component. And a photoinitiator and a coloring material. The photocurable ink is roughly classified into a radical polymerization ink containing a radical polymerizable compound as a polymerizable compound and a cationic polymerization ink containing a cationic polymerizable compound. Both inks are included in this embodiment. Each can be applied as an ink to be used. Further, a hybrid ink in which radical polymerization ink and cation polymerization ink are combined may be applied as the ink used in this embodiment. However, since cationic polymerization inks that have little or no inhibitory action on polymerization reaction due to oxygen are superior in functionality and versatility, it is particularly preferable to use cationic polymerization inks. The cationic polymerization ink is a mixture containing at least a cationic polymerizable compound such as an oxetane compound, an epoxy compound, and a vinyl ether compound, a photocationic initiator, and a coloring material.

  The ink used in this embodiment is a high-viscosity ink having a viscosity at 30 ° C. of 10 to 500 mPa · s. Since the viscosity of the ink is lowered by heating the ink, even when high-viscosity ink is smoothly ejected and ejected as fine droplets, the ink can be landed accurately on the recording medium to enable high-definition image recording. For this purpose, it is desirable to heat the temperature of the ink to 30 ° C. to 150 ° C. with a heater before discharging the ink.

  An ultraviolet irradiation device 8 having a length dimension substantially equal to the length of the recording head 7 in the recording medium conveyance direction X is provided inside the carriage 6 and between the side wall of the carriage 6 and the recording head 7. Extending in the longitudinal direction. The ultraviolet irradiation device 8 is provided with an ultraviolet light source (not shown). As the ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a semiconductor laser, a cold cathode tube, an excimer lamp, or an LED (Light Emitting Diode) can be applied. The position where the ultraviolet irradiation device 8 is provided is not limited to this. For example, the ultraviolet irradiation device 8 may be provided between the recording heads 7.

  In each of these recording heads 7, sub-tanks 10 for temporarily storing yellow (Y), magenta (M), cyan (C), and black (K) inks are formed of flexible materials. The ink supply pipe 9a is connected. Each sub tank 10 is connected to the main tank 11 via an ink supply pipe 9b. The ink in each main tank 11 is supplied to the sub tank 10 through the ink supply pipe 9b and temporarily stored in the sub tank 10. After that, it is supplied to each recording head 7. The sub tank 10 is provided at a lower position in FIG. By making the position of the sub-tank 10 lower than that of the recording head 7, the ink in the recording head 7 is kept in a negative pressure state so that the ink does not leak except during image recording.

  The sub tank 10 is provided with a sub tank sensor 27 that detects the amount of ink stored therein. For example, the sub tank sensor 27 detects the liquid level of the ink stored in the sub tank 10, and the amount of ink in the sub tank 10 depends on whether the liquid level of the ink is equal to or higher than a predetermined height. It is possible to grasp whether or not it is a predetermined amount or more. The sub tank sensor 27 is not limited to the one illustrated here as long as it can detect the amount of ink in the sub tank 10, and for example, a weight sensor or the like may be used.

  In addition, a damper 12 provided with an ink chamber 13 for storing ink therein is provided in the vicinity of the recording head 7 between the sub tank 10 and the recording head 7 in the middle of the ink supply pipe 9a. Is provided. Thus, by arranging the damper 12 close to the recording head 7, it is sufficient to supply the ink stored in the damper 12 to the recording head 7 when ejecting ink. , 9b, the effect of pressure loss that occurs when ink flows on ink discharge can be minimized. Thereby, even when high-viscosity ink is used for image recording, it is possible to prevent occurrence of ink ejection failure due to pressure loss.

  In FIG. 1 and FIG. 2, an ink inflow port 14 through which ink flows into the ink chamber 13 is provided at the upper end of the damper 12, and an ink outflow port 15 through which ink flows out from the ink chamber 13 at the lower end of the damper 12. Is provided. An ink supply pipe 9a is connected to each of the ink inlet 14 and the ink outlet 15, and the ink sent from the sub tank flows into the ink chamber 13 from the ink inlet 14 via the ink supply pipe 9a. The ink that has flowed into the ink chamber 13 is sent from the ink outlet 15 to the recording head 7 via the ink supply pipe 9a.

  An opening 16 is formed on one side surface of the ink chamber 13, and a damper film 17 is stretched over the opening 16. The damper film 17 is made of a flexible film such as a polyethylene film, for example, and is thermally welded to the opening 16 to seal the opening. The material of the flexible film constituting the damper film 17 is not limited to those exemplified here, but some inks used for image recording are corrosive, so at least directly contact the ink. It is desirable to use a material having corrosion resistance so that the damper film 17 is not deteriorated by the ink stored in the ink chamber 13 for the portion to be treated.

  A coil spring 18 as an elastic member is provided on the wall surface inside the ink chamber 13 and facing the opening 16 so that one end thereof is in contact with the damper film 17. The coil spring 18 supports the damper film 17 at a predetermined initial position when ink flows into the ink chamber 13 of the damper 12.

  Here, the initial position is a balance between the force of the ink flowing into the damper 12 flowing out toward the recording head 7 due to its own weight and the force of the coil spring 18 attempting to maintain the position of the film surface of the damper film 17. A position where a constant negative pressure generation state can be maintained. When ink flows into the ink chamber 13 of the damper 12, the damper film 17 is pressed by the ink and bent outward. On the contrary, when the ink in the ink chamber 13 is reduced by discharging ink from the recording head 7, the damper film 17 gradually tends to bend inward accordingly. At this time, the coil spring 18 is compressed by the damper film 17, thereby generating a repulsive force to return to the original length. The damper film 17 is pushed back to the initial position by the repulsive force of the coil spring 18, and the inside of the ink chamber 13 is in a negative pressure state in balance with the force that the damper film 17 is deflected inward. By maintaining the inside of the ink chamber 13 in a negative pressure state, it is possible to prevent ink from leaking from the nozzles of the recording head 7 other than during image recording. In the present embodiment, the coil spring 18 is used as the elastic member that supports the damper film 17. However, the elastic member may be a stretchable member that can support the damper film 17, and is limited to the coil spring 18. Not. Therefore, for example, various springs such as leaf springs and members such as stretchable resin may be used.

  On the outside of the damper 12 and in the vicinity where the damper film 17 is provided, the film surface of the damper film 17 serves as a remaining amount detecting means for detecting the remaining amount of ink stored in the ink chamber 13 of the damper 12. A film surface detection sensor 19 for detecting the position of the film is provided. The film surface detection sensor 19 has a rod 20 formed in a length longer than the length corresponding to the difference between the position when the damper film 17 is bent outward and the position when it is bent inward. The tip portion is provided in contact with the damper film 17. The rod 20 can move forward and backward with respect to the damper film 17 by an actuator such as a cylinder, for example, and protrudes or retracts as the damper film 17 bends, and the tip of the rod 20 always contacts the damper film 17. It is like that. The film surface detection sensor 19 includes, for example, a light emitter 21 that includes a light emitting element that emits light such as infrared light, and a light receiver 22 that includes a light receiving element that senses light emitted from the light emitter 21. The light emitter 21 and the light receiver 22 are arranged so that the light emitting surface (not shown) of the light emitter 21 and the light receiving surface (not shown) of the light receiver 22 face each other with the rod 20 in between. ing.

  When ink flows into the damper 12, the damper film 17 is pressed outward, and the rod 20 in contact with the damper film 17 is also pressed. When the rod 20 is pressed and pushed inward from the position where the light emitter 21 and the light receiver 22 in the film surface detection sensor 19 are provided, the light emitted from the light emitter 21 is blocked by the rod 20. Is not received by the light receiver 22. On the other hand, when the ink in the damper 12 decreases, the damper film 17 bends to the inside of the damper 12 and the rod 20 protrudes accordingly. When the rear end of the rod 20 protrudes before the position where the light emitter 21 and the light receiver 22 are provided, the light receiver 21 receives the light emitted from the light emitter 22. Accordingly, it can be detected that the rear end portion of the rod 20 is ahead of a predetermined position, and the position of the film surface of the damper film 17 with which the tip end portion of the rod 20 is in contact is lower than the predetermined position. It is possible to grasp whether or not it is bent inward.

  When the ink in the ink chamber 13 decreases, the damper film 17 is bent toward the inside of the ink chamber 13 accordingly. In order to prevent ink from leaking from the nozzles of the recording head 7, it is necessary to apply a certain negative pressure. However, when the damper film 17 is bent inward, the coil spring 18 brings the damper film 17 to the initial position by the repulsive force. By trying to push back, a negative pressure state is generated in the ink chamber 13 of the damper 12 and in the ink supply pipe 9 a from the damper 12 to the recording head 7. On the other hand, in order to properly eject ink from the nozzles, the weight of the ink stored in the damper 12 and the ink supply pipe 9a between the damper 12 and the recording head 7 is adjusted to the nozzles of the recording head 7. On the other hand, a predetermined pressure is required. When a certain amount or more of ink is stored in the damper 12, an appropriate pressure on the nozzle can be ensured, and the ink can be smoothly ejected by the ejection force of the recording head 7. When the negative pressure generated in the ink supply pipe 9a up to the damper 12 and the recording head 7 exceeds a certain limit, the ink cannot be properly ejected only by the ink ejection force of the recording head 7. For example, in general, the discharge force with which the recording head 7 can discharge ink is about −300 Pa, and if a negative pressure higher than this is applied, ink cannot be properly discharged from the nozzles, causing discharge failure. Become. Therefore, in order to maintain an appropriate pressure on the nozzle, it is possible to appropriately detect whether or not the ink remaining amount in the damper 12 is kept constant by detecting the film surface position of the damper film 17 by the film surface detection sensor 19. It is like that.

  A liquid feed pump 23 for feeding ink to the damper 12 is provided in the middle of the ink supply pipe 9a and between the damper 12 and the sub tank 10, and the amount of ink in the damper 12 becomes a certain amount or less. If it is determined that the ink has been stored, the ink stored in the sub tank 10 is forcibly sent. Note that various pumps such as a diaphragm pump and a gear pump can be applied as the liquid feed pump 23.

  A supply valve 24 for restricting the inflow of ink from the main tank 11 to the sub tank 10 is provided in the middle of the ink supply pipe 9b. The supply valve 24 is, for example, an electromagnetic valve including a solenoid and a diaphragm (both not shown), and the valve is opened and closed by liquid flowing into and out of the diaphragm by opening and closing the solenoid. Note that the mechanism for restricting inflow and outflow of ink is not limited to this, and various valves having other structures or other various mechanisms can be used.

  In addition, the inkjet printer 1 includes a display unit 28 as notification means for notifying the user when it is determined that there is no ink remaining in the main tank 11. The display unit 28 is configured by, for example, a liquid crystal display provided with a TFT (Thin Film Transistor) or the like, and which main tank 11 out of the main tank 11 that stores ink of each color has run out. Is displayed. It should be noted that the display unit 28 may be configured to display conditions relating to image recording and various other information in addition to the display relating to the remaining amount of ink in the main tank 11.

  The recording medium P used in this embodiment includes various paper such as plain paper, recycled paper, and glossy paper, various fabrics, various non-woven fabrics, and other non-ink-absorbing media such as resin, metal, and glass. The recording medium P made of various materials can be applied. In addition, as the form of the recording medium P, various forms such as a roll form, a cut sheet form, and a plate form are applicable.

  Next, the control configuration of the inkjet printer 1 according to the present embodiment will be described with reference to FIG.

  The ink jet printer 1 includes a control unit 25 that controls each unit of the ink jet printer 1, and a power source 26 that supplies power to the ink jet printer 1 is connected to the control unit 25.

  Further, a detection result obtained by detecting how much the film surface of the damper film 17 is bent inside the ink chamber 13 of the damper 12 is sent from the film surface detection sensor 19 to the control unit 25 as an electric signal. Yes. Based on this detection result, the control unit 25 determines whether or not ink remains in the ink chamber 13 of the damper 12, and when determining that no ink remains in the ink chamber 13, the liquid feeding pump 23 is operated so that the ink in the sub tank 10 is supplied to the damper 12. Note that the film surface of the damper film 17 is detected by the film surface detection sensor 19 during image recording when the carriage 6 is moving at a constant speed. The carriage 6 moves at a constant moving speed to perform stable image recording when performing image recording while reciprocating on the platen 2. However, except for the time of image recording, since it is not necessary to perform high-precision control, the moving speed of the carriage 6 is accelerated, or the moving speed of the carriage 6 is decreased to change the moving direction of the carriage 6. Is not constant. Further, when the cleaning operation of the recording head 7 is performed, the ink amount in the ink chamber 12 is abruptly changed due to forced ink suction or empty ejection. Therefore, it is impossible to expect an accurate value even if the film surface of the damper film 17 is detected other than during image recording when the carriage 6 is moving at a constant speed. Note that the detection of the film surface itself may be performed only at the time of image recording, or the detection of the film surface itself may be performed constantly or at predetermined intervals, and the control unit 25 detects the detection result at the time of image recording. It may be determined whether ink remains in the ink chamber 13 based only on the ink.

  When the control unit 25 determines that there is no ink in the ink chamber 13 of the damper 12 based on the signal sent from the film surface detection sensor 19, the control unit 25 appropriately operates the liquid feeding pump 23 to perform the ink chamber. An appropriate amount of ink that can be stored in the tank 13 is fed from the sub tank 10 to the ink chamber 13 of the damper 12 so that the amount of ink stored in the ink chamber 13 of the damper 12 is kept constant.

  In addition, a detection result of the ink amount in each sub tank 10 is sent from the sub tank sensor 27 to the control unit 25 as an electric signal. When the controller 25 determines from this detection result that the remaining amount of ink in the sub-tank 10 is less than or equal to a predetermined amount, the controller 25 operates the supply valve 24 to open the supply valve 24 for a predetermined period of time. Are supplied to the corresponding sub tanks 10 respectively. The time for opening the supply valve 24 is set in advance, for example, 10 seconds or 20 seconds, and the supply valve 24 is opened for the set time. The time for opening the supply valve 24 may be set according to the type of ink and the like.

  When it is determined from the information on the film surface position of the damper film 17 sent from the film surface detection sensor 19 that the position of the film surface of the damper film 17 has not changed even if the liquid feeding pump 23 is operated. The controller 25 determines that there is no ink remaining in the main tank 11. Note that the amount of ink remaining in the main tank 11 is determined as long as there is no change in the film surface position of the damper film 17 after the control unit 25 operates the liquid feeding pump 23. It may be changed according to various conditions such as type and ambient temperature. When the viscosity of the ink is high or when the ambient temperature is low, the flow rate of the ink is slower than when the viscosity of the ink is low, and even if the liquid feed pump 23 is operated, the ink chamber 13 of the damper 12 is moved. This is because the time taken for the ink to reach the ink chamber 13 of the damper 12 may be affected by the viscosity of the ink, etc. .

  When determining that there is no ink remaining in the main tank 11, the control unit 25 controls the display unit 28 to display for which color ink the ink remaining in the main tank 11 is exhausted. It has become.

  Further, the control unit 25 controls the carriage drive mechanism 29 to reciprocate the carriage 6 in the main scanning direction, and repeats the conveyance and stop of the recording medium P in accordance with the operation of the carriage 6, thereby intermittently recording the recording medium P. Therefore, the conveyance rollers 3 and 4 are operated by controlling the recording medium conveyance mechanism 30 so as to be conveyed in the conveyance direction X.

  In addition, the control unit 25 operates the recording head 7 to heat the ink in the ink flow path of the recording head 7 to about 30 ° C. to 150 ° C., and the ink is made into minute droplets of 2 to 20 pl per dot. A predetermined image is formed by discharging onto the recording medium P. Further, the control unit 25 controls the ultraviolet irradiation device 8 so that the ink landed on the recording medium P is irradiated with ultraviolet rays from an ultraviolet light source.

  Next, the operation in this embodiment will be described.

  When the power source 26 of the ink jet printer 1 is turned on, power is supplied from the power source 26 to each part of the ink jet printer 1, and the carriage 6 on which the recording head 7 is mounted moves above the platen 2.

  When the carriage 6 reaches a predetermined position, the recording medium P is transported in the transport direction X by the transport rollers 3 and 4, and at the same time, the carriage 6 reciprocates along the main scanning direction. At this time, a predetermined voltage is applied to the piezo element of the recording head 7 to compress the ink flow path, and the ink in the ink chamber 13 of the damper 12 is drawn into the ink flow path of the recording head 7 by this ejection force. Then, ink of a required color is ejected from the nozzle based on predetermined image information. Further, the discharged ink is irradiated with ultraviolet rays from the ultraviolet irradiation device 8, whereby a predetermined image is recorded on the recording medium P.

  When ink is ejected from the recording head 7, the ink stored in the ink chamber 13 of the damper 12 is sequentially supplied to the recording head 7, and the ink in the ink chamber 13 decreases. When the ink in the ink chamber 13 decreases, the damper film 17 bends toward the inside of the ink chamber 13 accordingly. When the damper film 17 bends inward, the coil spring 18 tries to push the damper film 17 back to the initial position by a repulsive force, and thereby the inside of the ink chamber 13 of the damper 12 and the inside of the ink supply pipe 9 a from the damper 12 to the recording head 7 are. It becomes a negative pressure state. The film surface position of the damper film 17 is detected by the film surface detection sensor 19 at any time, and the detection result is sent to the control unit 25.

  When it is detected that the damper film 17 is bent to the inner side of the predetermined position against the coil spring 18, an amount of ink that can be stored in the ink chamber 13 is sent from the sub tank 10 by the liquid feed pump 23. When the ink is properly fed, the damper film 17 is pressed outward by the pressure of the ink flowing into the ink chamber 13, and the rod 20 of the film surface detection sensor 19 is pressed by the damper film 17 along with this, and the film surface detection is performed. The sensor 19 is pushed into the main body, whereby the change in the position of the damper film 17 is grasped.

  In addition, the remaining amount of ink in the sub tank 10 is detected by the remaining amount detection sensor 19, and when the amount of ink in the sub tank 10 has decreased below a predetermined amount, the supply valve 24 is opened as needed to reach the required amount. Ink is supplied from the main tank 11 to the sub tank 10 via the ink supply pipe 9b. Thus, a certain amount of ink is always stored in the sub tank 10.

  Even when the liquid feed pump 23 is operated, ink does not flow into the ink chamber 13, and when the change in the film surface position of the damper film 17 is not detected by the film surface detection sensor 19, there is no ink remaining in the sub tank 10, and consequently It is determined that there is no ink remaining in the main tank 11 that supplies ink to the sub tank 10. Therefore, in this case, the display unit 28 displays that there is no ink remaining in the main tank 11.

  As described above, according to the present embodiment, it is detected whether or not ink remains in the main tank 11 by detecting the film surface position of the damper film 17 and grasping whether or not the damper 12 is replenished with ink. can do. For this reason, the remaining amount of ink in the main tank 11 can be accurately detected with a simple configuration, and the replenishment timing of the ink in the main tank 11 can be properly grasped.

  In addition, since the display unit 28 displays that there is no ink remaining in the main tank 11, the user can easily grasp the ink replenishment timing.

  In the present embodiment, since the damper 12 is provided in the vicinity of the recording head 7, the recording head 7 can be sequentially supplied with ink from the damper 12, and the ink supply tube 9 a for ink supplied to the recording head 7. The influence of the pressure loss inside can be minimized. For this reason, even when image recording is performed using high-viscosity ink, the ink can be guided to the nozzles of the recording head 7 by the ejection force of the recording head 7 and ejected.

  In the present embodiment, the damper 12 is provided with a damper film 17 formed of a flexible material, and the damper film 17 is kept at the initial position by the coil spring 18. By generating a negative pressure state, it is possible to prevent ink from leaking from the nozzles of the recording head 7.

  In the present embodiment, the sub tank 10 is provided in addition to the damper 12, and the ink in the main tank 11 is once supplied to the sub tank 10 and then supplied to the damper 12. FIG. As described above, the sub tank 10 may not be provided, and the ink of the main tank 11 may be directly supplied to the damper 12. In this case, the supply valve 24 between the main tank 11 and the sub tank 10 is not necessary, and the apparatus configuration is simplified. In general, the sub tank 10 manages the recording head 7 and the ink supply pipe 9a so as to maintain a constant negative pressure state, and plays a role of preventing ink from leaking out of the recording head 7 except during image recording. However, in the present embodiment, the negative pressure in the recording head 7 and the ink supply pipe 9a is maintained by the damper film 17 and the coil spring 18 of the damper 12. For this reason, even if the sub tank 10 is not provided, ink does not leak from the nozzles of the recording head 7.

  In the present embodiment, the display unit 28 is provided as a notification unit that notifies that there is no ink remaining in the main tank 11. However, the notification unit is not limited to this, and for example, an audio output unit is provided to provide a warning sound. The user may be informed that there is no ink remaining in the main tank 11 by generating a warning lamp or turning on the lamp.

  Further, as the ink jet printer 1 to which the ink jet printer 1 according to the present invention can be applied, either an on-demand type or a continuous type recording head 7 may be used. In addition, as a discharge method, for example, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, , Thermal ink jet type, bubble jet (registered trademark) type), electrostatic suction type (for example, electric field control type, slit jet type, etc.) and discharge type (for example, spark jet type, etc.) The recording head 7 may be used.

  In this embodiment, image recording is performed using ink that is cured by irradiation with ultraviolet rays. However, the ink is not necessarily limited to this, and for example, ultraviolet rays, electron beams, X-rays, and visible rays. The ink may be cured by irradiating light other than ultraviolet rays such as electromagnetic waves such as infrared rays. In this case, a polymerizable compound that is polymerized and cured with light other than ultraviolet light and a photoinitiator that initiates a polymerization reaction between the polymerizable compounds with light other than ultraviolet light are applied to the ink. In the case of using a photocurable ink that is cured by light other than ultraviolet light, a light source that emits the light is applied instead of the ultraviolet light source. Further, an ink that is cured and fixed without irradiating light may be used. In this case, it is not necessary to provide an ultraviolet irradiation device.

  Further, in the present embodiment, the ink jet printer 1 causes the recording head 7 mounted on the carriage 6 to reciprocate in the main scanning direction and ejects ink from the recording head 7 while transporting the recording medium P in the transport direction X. The serial head type ink jet printer 1 for forming an image is formed, but the ink jet printer 1 according to the present invention forms an image by ejecting ink from a recording head fixed to the printer body and transporting a recording medium. It may be a line head type inkjet printer.

  In addition, it is needless to say that the present invention is not limited to the above embodiment and can be modified as appropriate.

  Next, a second embodiment of the recording head according to the present invention will be described with reference to FIG. Since the second embodiment is different from the first embodiment only in the configuration of the remaining amount detecting means for detecting the amount of ink in the damper, the configuration of the remaining amount detecting means will be particularly described below.

  In the present embodiment, the inkjet printer 31 includes a recording head 32 that ejects ink, a main tank 35 that supplies ink to the recording head 32, and a sub-tank 34 that temporarily stores ink sent from the main tank 35. ing. The recording head 32 and the sub tank 34, and the sub tank 34 and the main tank 35 are connected by ink supply pipes 33a and 33b so that ink is sequentially supplied to the recording head 32.

  Further, in the middle of the ink supply pipe 32a, between the sub tank 34 and the recording head 32, and in the vicinity of the recording head 32, as in the first embodiment, an ink chamber (not shown) that stores ink therein. ) Is provided.

  An opening (not shown) is formed on one side surface of the ink chamber of the damper 36, and a damper film (not shown) made of a flexible film such as a polyethylene film is stretched over the opening. When the ink flows into the damper 36, the damper film is pressed by the ink and bends outward. Conversely, when the amount of ink in the damper 36 decreases as the ink flows out toward the recording head, the damper film bends inward. It has become.

  Further, a coil spring (not shown) as an elastic member is provided on the wall surface inside the ink chamber and facing the opening so that one end thereof is in contact with the damper film. Similar to the first embodiment, the coil spring is configured to support the damper film 11 at a predetermined initial position when ink flows into the ink chamber of the damper 36.

  In the middle of the ink supply pipe 33 a and between the damper 36 and the recording head 32, a pressure sensor that detects fluctuations in the pressure of ink flowing out of the damper 36 as a remaining amount detecting means for detecting the remaining amount of ink in the damper. 37 is provided.

  With the pressure sensor 37, for example, a bridge circuit is formed on a silicon substrate, and the electrical resistance changes when tension or compression is applied to a semiconductor crystal. For example, ceramic piezoelectric elements, polymer piezoelectric materials such as polyvinylidene fluoride, single crystal piezoelectric materials such as lithium niobate, and electrical conversion such as magnetostrictive ferrite are possible. A change in pressure can be grasped by detecting a change in electric resistance using a magnetostrictive element that generates pressure magnetism, a piezoelectric material that electrically converts strain such as a strain gauge, and the like.

  When there is sufficient ink in the damper 36, the pressing force for the ink to flow out toward the recording head 32 is strong, and the pressure applied to the ink supply pipe 33a between the damper 36 and the recording head 32 increases. On the other hand, when the remaining amount of ink in the damper 36 decreases, the pressing force that the ink tries to flow out toward the recording head 32 is weakened and applied to the ink supply pipe 33 a between the damper 36 and the recording head 32. The pressure becomes smaller. Therefore, the relationship between the amount of ink in the damper 36 and the pressure applied to the ink supply pipe 33a is measured and set in advance, so that the value detected by the pressure sensor 37 is at what level. It is possible to determine whether the remaining amount of ink is exhausted.

  A liquid feed pump 38 for feeding ink is provided between the damper 36 and the sub tank 34. When it is determined that the amount of ink in the damper 36 has become a certain amount or less, The ink stored in the ink is forcibly sent.

  A supply valve 39 for restricting the inflow of ink from the main tank 35 to the sub tank 34 is provided in the middle of the ink supply pipe 33b.

  Further, as in the first embodiment, the ink jet printer 31 includes a display unit (not shown) so as to appropriately display that the main tank 35 has no ink remaining.

  The ink jet printer 31 in this embodiment includes a control unit (not shown) that is substantially the same as that of the first embodiment, and the control unit includes a pressure sensor 37, a liquid feed pump 38, a supply valve 39, and a display unit. Is supposed to work. The carriage 6 is driven and ink is ejected from the recording head 32 based on a predetermined image signal to form a desired image.

  Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.

  Next, the operation of this embodiment will be described.

  When an image recording operation is performed based on a predetermined image signal and ink is ejected from the recording head 32, the ink stored in the ink chamber of the damper 36 is sequentially supplied to the recording head 32. Along with this, when the ink in the ink chamber is reduced, the damper film is bent toward the inside of the ink chamber. When the damper film is bent inward, the coil spring tries to push the damper film back to the initial position by the repulsive force, and thereby the negative pressure is generated in the ink chamber of the damper 36 and in the ink supply pipe 33 a from the damper 36 to the recording head 32. Go.

  A change in the pressure applied to the ink supply pipe 33a between the damper 36 and the recording head 32 is detected by the pressure sensor 37. It is determined that the amount is equal to or less than the predetermined amount, and an amount of ink that can be stored in the ink chamber is sent from the sub tank 34 by the liquid feed pump 38. When the ink is properly fed, the pressure applied to the ink supply pipe 33 a between the damper 36 and the recording head 32 increases, and the change in the pressure is detected by the pressure sensor 37.

  On the other hand, when the liquid feed pump 38 is operated, the ink does not flow into the ink chamber, and the pressure applied to the ink supply pipe 33a between the damper 36 and the recording head 32 does not change. Therefore, it is determined that there is no ink remaining in the main tank 35 that supplies ink to the sub tank 34. Therefore, in this case, the display unit displays that there is no ink remaining in the main tank 35.

  As described above, according to the present embodiment, the ink remaining amount in the main tank 35 is accurately detected by a simple configuration in which the pressure sensor 37 is provided in the ink supply pipe 33 a between the damper 36 and the recording head 32. Therefore, it is possible to appropriately grasp the replenishment timing of the ink in the main tank 35.

  Further, since the display unit displays that there is no ink remaining in the main tank 35, the user can easily grasp the ink replenishment timing.

  In the present embodiment, since the damper 36 is provided in the vicinity of the recording head 32, the recording head 32 can be sequentially supplied with ink from the damper 36, and the ink supply pipe 33 a for ink supplied to the recording head 32. The influence of the pressure loss in the inside can be minimized. For this reason, even when image recording is performed using high-viscosity ink, the ink can be guided to the nozzles of the recording head 32 by the discharging force of the recording head 32 and discharged.

  In the present embodiment, the damper 36 is provided with a damper film made of a flexible material, and the damper film is maintained at an initial position by a coil spring. This can prevent ink from leaking from the nozzles of the recording head 32.

  Note that the present invention is not limited to the present embodiment, as in the first embodiment.

It is a side view which shows typically the principal part of 1st embodiment of the inkjet printer which concerns on this invention. FIG. 2A is a side sectional view of a damper portion of the ink jet printer according to the present invention. FIG. 2B is a front view of the damper portion of the ink jet printer according to the present invention. It is a principal block diagram showing an outline of a control configuration of the first embodiment of the inkjet printer according to the present invention. It is a side view which shows one modification of 1st embodiment of the inkjet printer which concerns on this invention. It is a side view which shows typically the principal part of 2nd embodiment of the inkjet printer which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 7 Recording head 9a, 9b Ink supply pipe 12 Damper 13 Ink chamber 17 Damper film 18 Coil spring 19 Film surface detection sensor 20 Rod 21 Light emitter 22 Light receiver 23 Liquid feed pump 37 Pressure sensor P Recording medium X Transport direction

Claims (8)

An ink tank for storing ink, a recording head for discharging ink, and an ink supply pipe for supplying ink from the ink tank to the recording head,
A damper that temporarily stores ink is provided in the middle of the ink supply pipe, and a liquid feed pump that supplies ink to the damper is provided between the ink tank and the damper.
A remaining amount detecting means for detecting the remaining amount of ink in the damper, an informing means for notifying when there is no remaining ink in the ink tank, and the remaining amount detecting means is a remaining amount of ink in the damper. A controller for controlling the liquid feed pump so as to feed the ink in the ink tank to the damper when it is detected that the amount is equal to or less than a predetermined amount;
When the remaining amount detecting means does not detect an increase in the remaining amount of ink in the damper even when the liquid feeding pump is operated, the control unit determines that there is no remaining ink in the ink tank, and An ink jet printer characterized by notifying that effect by an informing means.   The damper includes an ink chamber for storing ink, and a flexible damper film is provided on at least one surface of the ink chamber, and an elastic member is provided to hold the damper film at a predetermined initial position. The inkjet printer according to claim 1.   3. The ink jet printer according to claim 1, wherein the remaining amount detecting means is a photo sensor that detects a position of the damper film or a pressure sensor that detects a pressure of ink flowing out of the damper. 4.   The recording head heats the ink, which is a liquid having a viscosity of 10 to 500 mPa · s at 30 ° C., to 30 to 150 ° C. by a heating unit, and discharges the ink so that one dot becomes a small droplet of 2 to 20 pl. The inkjet printer according to any one of claims 1 to 3, wherein:   The ink is a photocurable ink that is cured by irradiating light, and irradiates the ink that has landed on the recording medium downstream of the recording head in the transport direction of the recording medium. The inkjet printer according to claim 1, further comprising an apparatus.   6. The ink jet printer according to claim 5, wherein the ink is ultraviolet curable ink that is cured by irradiating with ultraviolet rays, and at least a part of the light emitted from the light irradiation device is ultraviolet rays. .   The ink jet printer according to any one of claims 1 to 6, wherein the ink is a high-viscosity ink and is a cationic polymerization type ultraviolet curable ink.   The ink jet printer according to claim 1, wherein the recording medium has no ink absorbability.

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