JP2008265125A - Ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer which can reduce pressure loss in an ink feeding pipe, produce a proper back pressure in the ink in a recording head when ink is supplied by a simple configuration, and perform stabilized image recoding. <P>SOLUTION: An ink supply pipe for supplying ink from an ink tank to a recording head is provided halfway with a damper provided with an ink chamber for storing ink temporarily and having a flexible damper film at least on one side of the ink chamber, and a pump located between the ink tank and the damper and feeding ink to the damper. A displacement of the damper film of the damper is detected at a plurality of detection points corresponding to the displacement, so that feeding of ink by means of the liquid feed pump is controlled depending on the detection point. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inkjet printer. Specifically, the present invention relates to ink supply of an ink jet printer.

  In general, ink jet printers are known as means capable of printing on various recording members. The ink jet printer uses, for example, a piezo element or a heater to eject ink as fine droplets toward a recording member such as paper from a nozzle at an ejection port provided in the recording head, and permeates the recording member. Or fix it. Then, along with the ejection of the ink, an image is recorded on the recording member by scanning a carriage on which the recording head is placed on the recording member. In particular, in recent years, inkjet printers using photocurable ink that is cured by light such as ultraviolet rays have been known. According to this, since the ink that has landed on the recording member is irradiated with light, the ink can be cured and fixed on the recording member, so that the recording member that does not absorb ink, such as a transparent or translucent resin film It is also possible to print easily.

  When high-viscosity ink is used for image recording in the ink jet printer, pressure loss caused by frictional resistance in the ink supply pipe cannot be ignored. For this reason, when ink is continuously ejected from the nozzles of the recording head, the ink cannot be sufficiently guided to the nozzles only by the ejection force of the recording head, and ink ejection failure may occur. .

  In addition, pressure fluctuations associated with deformation of the ink supply pipe during scanning of the recording head cause ink ejection to become unstable.

  For this reason, it is required to generate an appropriate back pressure for the ink of the recording head. The appropriate back pressure stabilizes ink ejection performance and prevents ink from leaking from the nozzles of the recording head.

  As means for preventing ink ejection failure due to pressure loss, means for reducing the frictional resistance in the ink supply pipe by increasing the diameter of the ink supply pipe or shortening the length of the ink supply pipe is known. .

  In addition, a sub tank for supplying ink to the print head is provided to shorten the distance from the sub tank to the print head, and a back pressure management pump for managing the back pressure of the ink is provided to reduce the influence of pressure loss. Means are known (for example, see Patent Document 1).

Also, a liquid feed pump and a damper are provided in the middle of the ink supply pipe, and the liquid feed pump is controlled by detecting the remaining amount of ink in the damper, the position of the damper film surface, or the pressure of the ink flowing out of the damper. There is a known method (see, for example, Patent Document 2).
Japanese Patent No. 2934016 JP 2006-21383 A

  However, when the ink to be used is a high-viscosity ink, in order to reduce the pressure loss to such an extent that does not affect image recording, it is desirable that the diameter of the ink supply pipe is 7 mm or more. The length of is preferably 1 m or less. However, such a diameter or length of the ink supply pipe has a problem that it is difficult to realize the design of the ink jet printer.

  Further, in Patent Document 1, the subtank is disposed in the vicinity of the recording head or a back pressure management pump is disposed, which complicates the apparatus configuration of the ink jet printer. In particular, in order to arrange the subtanks immediately before the recording heads, it is necessary to mount the number of subtanks corresponding to the number of recording heads on the carriage, which increases the size and weight of the carriage, resulting in the large size of the entire apparatus. Cause weight and weight. Further, in order to drive such a large carriage, it is necessary to reinforce the carriage drive system, and there is a problem that the apparatus cost increases.

  Patent Document 2 is a method of managing the back pressure by using a damper to detect the remaining amount of ink in the damper and supplying and replenishing ink. However, the back pressure is set only at one point, and the recording head The back pressure setting cannot be adjusted according to the change in the ink discharge amount. With a constant back pressure, it is difficult to cope with the change in pressure loss due to the change in discharge amount, and it is difficult to obtain an appropriate discharge droplet amount.

  Here, the ejection amount is an ink amount ejected per unit time by one recording head to which ink is supplied from one ink supply tube, and is represented by an ink amount ejected per minute, for example. The appropriate amount of discharged liquid (hereinafter also abbreviated as droplet amount) is the amount of each discharged ink droplet.

  The present invention has been made in view of the above situation, and can reduce ink pressure loss with a simple configuration and generate an appropriate back pressure on the ink of the recording head, thereby performing stable image recording. An object of the present invention is to provide an ink jet printer that can be used.

The above object is achieved by the following configuration.
1. In an ink jet printer having a recording head having an ink discharge port for discharging ink to form an image on a recording member, an ink tank for storing the ink, and an ink supply for supplying ink from the ink tank to the recording head A damper having an ink chamber that temporarily stores ink in the middle of the ink supply pipe and having a flexible damper film on at least one surface of the ink chamber; and the ink tank and the damper A liquid feed pump for feeding ink to the damper in between, a detection unit for detecting the amount of displacement of the damper film of the damper at a plurality of detection points corresponding to the amount of displacement, and the feeding according to the detection point An ink jet printer comprising: a control unit that controls ink feeding by a liquid pump.
2. 2. The inkjet printer according to 1, wherein the detection unit includes an optical sensor, and the displacement amount of the damper film is detected by the optical sensor.
3. The damper film includes a reflection member that is displaced along with the displacement of the damper film, and an optical sensor having one light emitting part and a plurality of light receiving parts, and emits a light beam from the one light emitting part toward the reflecting plate. A plurality of light receiving portions provided on a plurality of optical axes of reflected light that is irradiated and displaced according to the amount of displacement of the reflecting plate receives the reflected light at positions corresponding to the amount of displacement, and the displacement of the damper film 3. The ink jet printer according to 2, wherein the amount is detected.
4). The damper film is provided with a displacement member that is displaced along with the displacement of the damper film, and an optical sensor having a plurality of pairs of a light emitting part and a light receiving part. The optical sensor detects the displacement of the displacement member, and the damper 3. The ink jet printer according to 2, wherein a displacement amount of the film is detected.
5. 2. The ink jet printer according to 1, wherein the detection unit includes a magnetic sensor, and the displacement amount of the damper film is detected by the magnetic sensor.
6). The damper film includes a magnetic member that is displaced along with the displacement of the damper film, and includes a plurality of magnetic sensors, the displacement of the magnetic member is detected by the magnetic sensor, and the amount of displacement of the damper film is detected. 6. The ink jet printer according to 5, wherein

  With the above configuration, the ink is supplied to the recording head from the damper provided immediately before the recording head, and the ink is supplied to the damper by the liquid supply pump when the ink in the damper is reduced. Loss can be reduced. In addition, it is possible to prevent ink ejection from becoming unstable due to pressure fluctuations caused by deformation of the ink supply pipe during scanning of the recording head. Further, since it is not necessary to arrange a member such as a sub tank on the carriage, the carriage can be reduced in size and cost.

  Furthermore, since the displacement of the damper film can be detected in stages, it is possible to select a target set back pressure. Thereby, appropriate back pressure management can be performed according to various printing conditions.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1 is a conceptual diagram of an inkjet printer 100 according to the present invention, and FIG. 2 is a schematic side view. The ink jet printer of the present invention is not limited to the following form.

  An ink jet printer 100 shown in FIGS. 1 and 2 is an ink jet printer using a serial printing method, and is provided with a platen 2 that is formed in a flat plate shape and supports a recording member P from a non-recording surface. Conveying rollers 3 and 4 are provided on the upstream side and downstream side of the platen 2 to convey the recording member P while maintaining substantially the same height as the platen 2. It is conveyed in the B direction. The transport rollers 3 and 4 are rotationally driven by a recording member transport mechanism 29 (see FIG. 4).

  Above the platen 2, a guide member 5 is provided in the main scanning direction (arrow A direction) orthogonal to the conveyance direction (arrow B direction) of the recording member P. A carriage 6 is supported on the guide member 5, and the carriage 6 reciprocates in the main scanning direction along the guide member 5 by a carriage drive mechanism 28 (see FIG. 4).

  A recording head 7 corresponding to each color ink to be used is mounted on the carriage 6. In the present embodiment, yellow (Y), magenta (M), cyan (C), and black (K) inks, and light yellow (LY) having a lower density than the inks are used to express the gradation of the image more precisely. ), A recording head 7 corresponding to each ink of light magenta (LM), light cyan (LC), and light black (LK).

  The recording head 7 is reciprocated in the main scanning direction by the reciprocating movement of the carriage 6 in the main scanning direction, and performs image recording by discharging ink in the process. The cap unit 110 disposed at the standby position of the recording head prevents drying of the nozzles and discharge port surfaces of the recording head. The cleaning unit 120 performs cleaning of the nozzle and the discharge port surface.

  A plurality of nozzles (not shown) for ejecting ink are provided on the surface of the recording head 7 facing the recording member P. For example, the nozzle of the recording head 7 is provided with a piezo element (not shown) as a piezoelectric element that is deformed by applying a voltage, 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.

  The ink used in the present embodiment is a photocurable ink having a property of being cured when irradiated with ultraviolet rays, and contains at least a polymerizable compound (including a known polymerizable compound) as a main component. It contains a photoinitiator and a color 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 member conveyance direction B 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.

  The recording head 7 is supplied with the ink from an ink tank 11 that stores the ink through flexible ink supply pipes 9a and 9b. A liquid feed pump 20 for feeding the ink is provided between the ink supply pipes 9a and 9b. As the liquid feed pump 20, various pumps such as a diaphragm pump and a gear pump can be used.

Further, as shown in FIG. 2, an ink chamber 122 for storing ink is provided in the middle of the ink supply pipe 9a and between the liquid feed pump 20 and the recording head 7 in the vicinity of the recording head 7. A damper 12 is provided.
As described above, by disposing 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. It is possible to minimize the influence of the pressure loss generated when the ink flows through the ink 9a on the ink ejection.

  FIG. 3 is a cross-sectional view of the damper 12. An ink inlet 123 through which ink flows into the ink chamber 122 is provided at one upper end of the damper frame 121, and an ink outlet 124 through which ink flows out from the ink chamber 122 is provided at the lower end of the damper frame 121. A supply pipe 9a is connected.

  The ink sent from the liquid feed pump 20 flows into the ink chamber 122 from the ink inlet 123 through the ink supply pipe 9a, and the ink flowing into the ink chamber 122 flows into the ink outlet 124 through the ink supply pipe 9a. To the recording head 7.

  An opening is formed on one side surface of the ink chamber 122, and a damper film 125 is provided in the opening. The damper film 125 is made of, for example, a flexible film such as a polyethylene film. For example, the damper film 125 is thermally welded to the opening end portion of the damper frame 121 to seal the opening portion. Note that the flexible material constituting the damper film 125 is not limited to the above. Some of the materials have corrosive properties depending on the ink used for image recording. Therefore, it is desirable that at least a portion in direct contact with the ink is resistant to the ink stored in the ink chamber 122.

On the wall surface facing the opening inside the damper frame 121, a film surface position regulating member made of an elastic member is provided so that one end is locked to the damper film 125 and the other end is locked to the wall surface. . In the present embodiment, a coil spring 127 is used as the film surface position regulating member. The coil spring 127 supports the damper film 125 at a predetermined initial position when ink flows into the ink chamber 122 of the damper 12.
Here, the initial position is a balance between the force that the ink flowing into the damper 12 tends to flow out toward the recording head 7 due to its own weight and the force that the coil spring 127 tries to hold the position of the film surface of the damper film 125. A position where a constant negative pressure (negative back pressure) can be maintained. When the ink flows into the ink chamber 122 of the damper 12, the damper film 125 is pressed by the ink and bent outward. On the contrary, when the ink in the ink chamber 122 is reduced by discharging ink from the recording head 7, the damper film 125 gradually tends to bend inward accordingly. At this time, the coil spring 127 is compressed by the damper film 125, thereby generating a repulsive force for returning to the original length. The damper film 125 is pushed back to the initial position by the repulsive force of the coil spring 127, and the damper film 125 balances with the force to bend inward so that the ink chamber 122 is in a negative pressure state. By keeping the inside of the ink chamber 122 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 this embodiment, the coil spring 127 is used as the elastic member that supports the damper film 125. However, the elastic member may be any elastic member that can support the damper film 125, and is limited to the coil spring 127. Not. Therefore, for example, various springs such as leaf springs and members such as stretchable resin may be used.

  In the vicinity of the damper film 125 outside the damper 12, a detection unit 13 is provided that detects the displacement of the damper film 125 that is displaced according to the amount of ink in the ink chamber 122 at a plurality of detection points corresponding to the displacement. In the present embodiment, the detection point includes the initial position (position in FIG. 3B), the position where the damper film 125 is bent outward (ie, the convex state, the position shown in FIG. 3A), and the position where the damper film 125 is bent inward (ie, the concave). State, position in FIG. 3C).

  The detection unit 13 includes an optical sensor including one light emitting unit 131 and three light receiving units 132a, 132b, and 132c. In addition, a reflection plate 126 that reflects the light beam emitted from the light emitting unit 131 is provided at the center of the outer surface of the damper film 125 as the damper film 125 is displaced.

  The light beam emitted from the light emitting unit 131 is reflected by the reflecting plate 126 and detected by each light receiving unit of the light receiving units 132a, 132b, and 132c arranged on the optical axis of the reflected light corresponding to the three positions. . Thereby, the displacement of the damper film 125 is detected. Based on the detection of the displacement of the damper film 125, the liquid feed pump 20 is controlled.

  Next, the control of the liquid feeding pump 20 based on the position detection of the damper film 125 will be described. The control is performed at the time of image recording, in which the recording head 7 is reciprocated in the main scanning direction, and image recording is performed by discharging ink in the process.

  In order to properly eject ink from the nozzles when ink is ejected from the recording head 7, a predetermined negative back pressure corresponding to the ejection force of the recording head 7 is applied to the nozzles. It is necessary to be.

  However, when the back pressure is constant, it is difficult to obtain an appropriate droplet amount because it cannot cope with a change in pressure loss due to a change in the condition of image recording, that is, a discharge amount of ink. For example, when the ink discharge amount of the recording head 7 is classified into three stages of a large amount (H), a medium amount (M), and a small amount (L), when discharging at H compared to discharging at M, It is necessary to increase the amount of ink supplied, and the ink flow rate in the ink supply pipe 9a increases and the pressure loss increases. For this reason, if ejection is performed with H while the back pressure is appropriate with M, the required amount of ink is not supplied, and the appropriate amount of liquid is reduced. Further, when the discharge at L is performed with the back pressure at M, the reverse state occurs. For this reason, back pressure management and maintenance corresponding to the discharge amount are required.

  In contrast, in the present embodiment, by controlling the liquid feed pump 20, the amount of ink supplied to the damper 12 is controlled, and the back pressure is managed.

  The carriage moves to a predetermined position in response to an instruction to start image recording by the inkjet printer 100. At this time, the ink is supplied to the damper 12 by the liquid feed pump 20 to the position shown in FIG. 3B, and the light beam emitted from the light emitting unit 131 is reflected by the reflecting plate 126 located at the position shown in FIG. 3B and is received by the light receiving unit 132b. Received light.

  The liquid feed pump 20 is controlled according to image recording based on the ink discharge amount information of the image recording information for controlling the ink discharge of the nozzles and the position detection information of the damper film 125.

  When the ink discharge amount is large (H), ink is supplied from the liquid feed pump 20 to the damper 12, and the damper film 125 is bent outward from the position in FIG. 3B and detected by the light receiving unit 132a at the position in FIG. 3A. After the detection, the liquid feed pump 20 is driven for a predetermined time and stopped. As a result, the damper film 125 is further bent outward. As the ink is ejected from the nozzle, the damper film 125 returns to the position shown in FIG. 3A and is detected by the light receiving unit 132a. After the detection, the liquid feed pump 20 is again driven for a certain time and stopped. In this way, by repeating the detection of the position of the damper film 125 and the control of the liquid feeding pump 20, the inside of the ink chamber 122 of the damper 12 is maintained at a constant pressure. In the present embodiment, the pressure is a pressure for feeding ink in the nozzle direction, that is, a positive pressure. The pressure is appropriately selected from the ink discharge amount, the pressure loss, and the discharge force of the recording head, and is not limited to the present embodiment.

  As described above, it is necessary to increase the amount of ink supplied to the nozzles when discharging with H compared to when discharging with M, but the pressure loss also increases. On the other hand, by maintaining the inside of the ink chamber 122 at a constant pressure as described above, the influence of the pressure loss can be reduced, and when the ink discharge amount is H, the back pressure to the nozzle is set appropriately. Negative pressure can be set. Furthermore, the back pressure of H can be set to a negative back pressure whose absolute value is smaller than the back pressure of M.

  As a result, when the ink discharge amount is H, an appropriate back pressure corresponding to the discharge amount is maintained and an appropriate liquid amount can be obtained.

  Hereinafter, the back pressure at H is referred to as low back pressure, the back pressure at M is referred to as medium back pressure, and the back pressure at L is referred to as high back pressure.

  When the ink discharge amount is medium amount (M), the liquid feed pump 20 is driven for a predetermined time and stopped. Thereby, the damper film | membrane 125 bends to the FIG. 3B position outer side. As the ink is ejected from the nozzles, the damper film 125 returns to the position shown in FIG. 3B and is detected by the light receiving unit 132b. After the detection, the liquid feed pump 20 is again driven for a certain time and stopped. In this way, by repeating the detection of the position of the damper film 125 and the control of the liquid feeding pump 20, the inside of the ink chamber 122 of the damper 12 is maintained at a constant pressure. In this embodiment, the pressure is set to a substantially positive / negative pressure that does not feed the ink in the ink chamber 122 in the nozzle direction and does not draw the ink in the ink supply pipe 9a into the ink chamber 122. The pressure is appropriately selected from the ink discharge amount, the pressure loss, and the discharge force of the recording head, and is not limited to the present embodiment. For this reason, pressure loss is included and the back pressure with respect to a nozzle can be made into an appropriate negative pressure (medium back pressure). Thereby, when the ink discharge amount is M, an appropriate back pressure corresponding to the ejection amount is maintained, and an appropriate liquid amount can be obtained.

When the ink discharge amount is small (L), when the ink starts to be discharged from the nozzle and the ink in the ink chamber 122 decreases, the damper film 125 bends inward in FIG. 3B, and at the position of FIG. Detected. After the detection, the liquid feed pump 20 is driven for a predetermined time and stopped. Thereby, the damper film | membrane 125 bends outside. As the ink is ejected from the nozzles, the damper film 125 returns to the position shown in FIG. 3C and is detected by the light receiving unit 132c. After the detection, the liquid feed pump 20 is again driven for a certain time and stopped. In this way, by repeating the detection of the position of the damper film 125 and the control of the liquid feeding pump 20, the inside of the ink chamber 122 of the damper 12 is maintained at a constant pressure.
In the present embodiment, the pressure is a pressure that draws the ink in the ink supply pipe 9a into the ink chamber 122, that is, a negative pressure. The pressure is appropriately selected from the ink discharge amount, the pressure loss, and the discharge force of the recording head, and is not limited to the present embodiment.

  As described above, since the pressure loss in the ink supply pipe 9a becomes smaller during ejection in L than in ejection in M, the back pressure to the nozzle is insufficient. On the other hand, by maintaining the inside of the ink chamber 122 at a constant pressure as described above, the back pressure with respect to the nozzle when the ink discharge amount is L including the pressure loss can be set to an appropriate negative pressure. it can. Further, the L back pressure can be set to a negative back pressure having an absolute value larger than the M back pressure.

  As a result, when the ink discharge amount is L, an appropriate back pressure corresponding to the discharge amount is maintained and an appropriate liquid amount can be obtained.

  As described above, the ink is supplied to the recording head from the damper provided immediately before the recording head, and when the ink in the damper is reduced, the ink is supplied to the damper by the liquid supply pump. Can be lowered. In addition, the damper can prevent ink ejection from becoming unstable due to pressure fluctuations associated with deformation of the ink supply tube during scanning of the recording head. Further, since it is not necessary to arrange a member such as a sub tank on the carriage, the carriage can be reduced in size and cost.

  Furthermore, since the displacement of the damper film is detected stepwise, it is possible to select a target set back pressure. As a result, the back pressure setting can be gradually lowered, medium, and high according to the discharge amount, high, medium, and low, and it becomes possible to maintain an appropriate back pressure according to each discharge amount. An appropriate amount of liquid can be obtained. Therefore, appropriate back pressure management can be performed according to various printing conditions, and high-quality image recording can be performed.

  Next, a control configuration of the ink jet printer 100 according to the present embodiment will be described with reference to FIG.

  The ink jet printer 100 includes a control unit 25 that controls each unit of the ink jet printer 100, and a power source 26 that supplies power to the ink jet printer 100 is connected to the control unit 25.

  Further, the detection result obtained by detecting the displacement position of the damper film 125 is sent from the detection unit 13 to the control unit 25 as an electric signal. The control unit 25 determines the position of the damper film 125 based on the detection result, and controls the liquid feeding pump 20.

  The position of the damper film 125 is detected by the detection unit 13 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 122 is abruptly changed due to forced suction of ink and empty ejection. Therefore, it is impossible to expect an accurate value even if the film surface of the damper film 125 is detected other than during image recording when the carriage 6 is moving at a constant speed. The position detection of the damper film 125 may be performed only at the time of image recording, or may be performed always or at predetermined intervals, and the control unit 25 detects only the detection result detected at the time of image recording. A determination may be made based on this.

  The control unit 25 determines the position of the damper film 125 based on the signal sent from the detection unit 13, operates the liquid feeding pump 20 as appropriate, and supplies a predetermined amount of ink from the ink tank 11 to the ink chamber 122 of the damper 12. To liquid.

  Further, the control unit 25 controls the carriage drive mechanism 28 to reciprocate the carriage 6 in the main scanning direction, and repeats the conveyance and stop of the recording member P in accordance with the operation of the carriage 6, thereby intermittently recording the recording member P. Therefore, the recording roller transport mechanism 29 is controlled to operate the transport rollers 3 and 4 so that the transport rollers 3 and 4 are transported in the transport direction B.

  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 member P is irradiated with ultraviolet rays from an ultraviolet light source.

  As the recording member P used in the present embodiment, various papers such as plain paper, recycled paper, glossy paper, various fabrics, various non-woven fabrics, etc., non-ink-absorbing materials such as resin, metal, glass, etc. Recording media P made of various materials can be applied. Further, as the form of the recording member P, various forms such as a roll form, a cut sheet form, and a plate form are applicable.

  The ink jet printer 100 is not limited to the present embodiment, and may use either an on-demand type or a continuous type recording head 7. 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, visible The ink may be cured by irradiating light other than ultraviolet rays such as light rays and 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 100 reciprocates the recording head 7 mounted on the carriage 6 in the main scanning direction and ejects ink from the recording head 7 while transporting the recording member P in the transport direction B. Thus, the serial head type ink jet printer 100 for forming an image is used. However, the ink jet printer 100 according to the present invention ejects ink from the recording head fixed to the printer body and conveys the recording medium to transfer the image. It may be a line head type ink jet printer to be formed.

Next, another embodiment of the recording head according to the present invention will be described. Since another embodiment is different from the above-described embodiment only in the configuration of the detection unit that detects the position of the damper film 125, the configuration of the detection unit will be described below.
(Another form 1)
FIG. 5 is a diagram illustrating another embodiment 1 in which an optical sensor configured by a plurality of pairs of a light emitting unit and a light receiving unit is used as a detection unit that detects the position of the damper film 125.

  The damper film 125 is provided with a light-shielding displacement member 226 that is displaced along with the displacement of the damper film 125. The detection unit 230 has a transmission type optical sensor composed of a plurality of pairs of a light emitting unit and a light receiving unit, and the light emitting unit 231a and the light receiving unit 231b, the light emitting unit 232a and the light receiving unit 232b, and the light emitting unit 233a and the light receiving unit 233b are displaced. The member 226 is sandwiched and arranged at opposing positions. Each sensor is arranged so as to detect a position where the damper film 125 is bent outward by a predetermined amount from the position shown in FIGS.

  When the ink discharge amount is large (H), the liquid feed pump 20 is driven, the ink is supplied from the liquid feed pump 20 to the damper 12, and the damper film 125 bends outward in the position of FIG. 5B. At the position where the damper film 125 is bent outward by a predetermined amount from the position in FIG. 5A, the displacement member 226 blocks the optical path between the light emitting portion 231a and the light receiving portion 231b, and it is detected that the displacement member 226 is present, and the pump 20 stops. When the ink is ejected from the nozzle, the damper film 125 bends inward, returns to the position in FIG. 5A, and the displacement member 226 opens the optical path of the light emitting portion 231a and the light receiving portion 231b, it is detected that the displacement member 226 is absent and the pump 20 is driven. Supplied. The driving and stopping of the pump as described above are repeated.

  Even when the ink discharge amount is medium amount (M) and small amount (L), the position of the damper film 125 is detected by each sensor (light emitting unit 232a, light receiving unit 232b, light emitting unit 233a light receiving unit 233b) as described above. Take control.

In this embodiment, the configuration is complicated as compared with the above-described embodiment, but the displacement process of the detection unit displacement member 226, that is, the damper film 125, can be more clearly identified. Further, it is easy to individually adjust the position of the sensor. In this embodiment, a transmissive optical sensor is used as the sensor, but a reflective type sensor may be used.
(Another form 2)
FIG. 6 is a diagram showing another embodiment 2 in which a magnetic sensor is used as a detection unit that detects the position of the damper film 125.

  The damper film 125 is provided with a magnetic member 332 that is displaced along with the displacement of the damper film, and a plurality of magnetic sensors 331a, b, and c, and by detecting the displacement of the magnetic member 332, the amount of displacement of the damper film 125 is reduced. It detects and controls the liquid feeding pump 20. About the said control, it applies to the above-mentioned embodiment.

1 is a conceptual diagram of an inkjet printer according to the present invention. 1 is a schematic side view of an ink jet printer according to the present invention. It is a figure of a section of a damper concerning the present invention, and a detection part. It is a schematic block diagram of the control structure of the inkjet printer which concerns on this invention. It is a figure which shows another form 1 of the detection part which detects the position of a damper film | membrane. It is a figure which shows another form 2 of the detection part which detects the position of a damper film | membrane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Inkjet printer 2 Platen 3, 4 Conveyance roller 5 Guide member 6 Carriage 7 Recording head 9a, 9b Ink supply pipe 11 Ink tank 12 Damper 121 Damper frame 122 Ink chamber 125 Damper film 126 Reflector 127 Coil spring 13 Detection part 131 Light emission part 132a , 132b, 132c Light receiving part 20 Liquid feed pump P Recording member

Claims (6)

In an ink jet printer having a recording head provided with an ink ejection port for ejecting ink onto a recording member to form an image,
An ink tank for storing the ink;
An ink supply pipe for supplying ink from the ink tank to the recording head;
A damper provided with an ink chamber for temporarily storing ink in the middle of the ink supply pipe and provided with a flexible damper film on at least one surface of the ink chamber;
A liquid feed pump for feeding ink to the damper between the ink tank and the damper;
A detection unit for detecting a displacement amount of the damper film of the damper at a plurality of detection points corresponding to the displacement amount;
A control unit that controls ink feeding by the liquid feeding pump according to the detection point;
An ink jet printer comprising: The ink jet printer according to claim 1, wherein the detection unit includes an optical sensor, and the displacement amount of the damper film is detected by the optical sensor. The damper film is provided with a reflection member that is displaced along with the displacement of the damper film, and an optical sensor having one light emitting part and a plurality of light receiving parts,
A plurality of light receiving units provided on a plurality of optical axes of reflected light that irradiates a light beam from the one light emitting unit toward the reflecting plate and is displaced according to the amount of displacement of the reflecting plate, according to the amount of displacement. The inkjet printer according to claim 2, wherein the reflected light is received at a predetermined position to detect a displacement amount of the damper film. The damper film is provided with a displacement member that is displaced along with the displacement of the damper film, and an optical sensor having a plurality of pairs of a light emitting part and a light receiving part,
The inkjet printer according to claim 2, wherein a displacement of the displacement member is detected by the optical sensor, and a displacement amount of the damper film is detected. The ink jet printer according to claim 1, wherein the detection unit includes a magnetic sensor, and the displacement amount of the damper film is detected by the magnetic sensor. The damper film includes a magnetic member that is displaced along with the displacement of the damper film, and a plurality of magnetic sensors.
6. The inkjet printer according to claim 5, wherein the magnetic sensor detects a displacement of the magnetic member and detects a displacement amount of the damper film.

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