JP2011240624A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent liquid in a discharge port from being dried, while reducing the liquid consumption.SOLUTION: An internal space 110a is formed between a cap 110 and a discharge surface 2a of a head 2, when the cap 110 covers the discharge surface 2a. When the head 2 is separated from the discharge surface 2a, high humidity air in the internal space 110a is sucked into a storage chamber 124a, before the head 2 is separated from the discharge surface 2a. When the cap 110 is temporarily separated from the discharge surface 2a and then covers the discharge surface 2a again, the high humidity air saved in the storage chamber 124a is returned into the internal space 110a.

Description

  The present invention relates to a recording apparatus having a recording head that discharges a liquid containing water as a component.

  In order to prevent drying of the liquid in the discharge port for discharging the liquid in the recording head, the discharge surface on which the discharge port is formed may be covered with a cap during a period in which the liquid is not discharged. However, immediately after the ejection surface of the recording head is covered with the cap, the air in the cap is relatively dry, and moisture continues to evaporate from the ejection port until the water vapor in the cap becomes saturated. On the other hand, in patent document 1, the capping means which covers the nozzle formation surface of the head is provided with an air opening and a valve member for opening and closing the air opening. When the apparatus is stopped for a long period of time, the air opening is opened to promote ink drying at the nozzle, and the ink is solidified from the nozzle opening to the back by solidifying the ink at the nozzle opening. It is said that it can be prevented.

JP 2000-218806 A

  According to Patent Document 1, ink is solidified at the nozzle opening during capping. For this reason, before the ink is ejected from the nozzle and the recording operation on the recording medium is executed, it is necessary to eject the ink preliminarily from the nozzle to remove the solidified ink. Therefore, there is a risk that ink will be consumed excessively.

  An object of the present invention is to provide a recording apparatus capable of suppressing the drying of the liquid in the discharge port while suppressing the consumption of the liquid.

  The recording apparatus according to the present invention includes a recording head having a discharge surface on which a discharge port for discharging a liquid containing water as a component is formed, and a capping unit that contacts the discharge surface and covers a discharge region in which the discharge port is formed. The capping means is moved relative to the recording head between a covering position that is in contact with the discharge surface and covers the discharge region, and a separation position that is separated from the discharge surface and opens the discharge region. When the cap moving means and the capping means are at the covering position, the external communication flow path for communicating the internal space formed between the capping means and the discharge surface and the outside thereof, and air is stored. An air storage means that has a storage chamber and moves air between the internal space and the storage chamber, and before the capping means starts to move from the covering position to the separation position. The cap moving means and the cap moving means so that air flows into the storage chamber from the inclusion space and the air in the storage chamber flows into the inclusion space after the capping means moves from the separation position to the covering position. Control means for controlling the air storage means.

  When the capping means is moved from the separation position to the covering position, moisture evaporates from the discharge port, but if the air in the internal space becomes saturated, drying in the discharge port does not proceed any further. However, if the capping means is moved from the covering position to the separation position after that, the humid air in the internal space is dissipated into the atmosphere, so even if the capping means is moved to the covering position again, Since the air in the enclosing space is as dry as the outside air, the water evaporates from the discharge port. On the other hand, according to the recording apparatus of the present invention, the air moved from the inclusion space before the capping means is moved from the covering position to the separation position, and the air is moved after the capping means is moved from the separation position to the covering position. Return to space. Therefore, the inside space is in a highly humid state and the liquid near the discharge port is prevented from drying. Further, since the drying of the liquid in the discharge port is not promoted, the amount of liquid to be preliminarily discharged can be suppressed, or the preliminary discharge itself can be made unnecessary.

  Moreover, in this invention, it is preferable that the said air storage means has a suction means which attracts | sucks air from the said inclusion space when air is made to flow in into the said storage chamber. According to this, since air moves from the inclusion space to the storage chamber by suction, for example, compared with the case of moving by pressurization, the mixing of outside air into the storage chamber can be reduced, and high humidity air remains in the storage chamber. Can be evacuated.

  In the present invention, the discharge region is elongated in one direction, and the air storage means has a suction channel for introducing air sucked from the inclusion space into the storage chamber, A communication portion between the suction flow path and the internal space is disposed in the vicinity of one end of the internal space with respect to the one direction, and a communication portion between the external communication flow path and the internal space is the internal space with respect to the one direction. It is preferable to arrange | position in the other end vicinity. According to this, since the communication portion between the inclusion space and the suction flow path is arranged at one end and the communication portion between the external communication flow path and the inclusion space is arranged at the other end, Air in the internal space can be sucked smoothly.

  In the present invention, it is preferable that the internal space is tapered toward the one end and tapered toward the other end. According to this, since the internal space is tapered toward the one end where the communicating portion with the suction channel is disposed, the high-humidity air in the internal space smoothly flows into the storage chamber without causing retention. Sucked. Further, since the internal space is tapered toward the other end where the communication portion with the external communication channel is disposed, external air is smoothly introduced from the external communication channel into the internal space.

  In the present invention, it is preferable that the control means controls the air storage means so as to suck the air in the inclusion space at a speed that does not generate turbulent flow. According to this, since suction is performed so that turbulent flow does not occur in the internal space, the air flowing into the internal space through the external communication channel and the high-humidity air existing in the internal space are difficult to mix, and only the high-humidity air is mixed. It is easy to be sucked into the storage chamber smoothly.

  Moreover, in this invention, the said air storage means may have a displacement member which changes the volume of the said storage chamber by displacing in the said storage chamber. According to this, air can be sucked into the storage chamber with a simple configuration.

  Moreover, in this invention, the said air storage means has a 1st humidification means to humidify the air moved from the said inclusion space until it returns to the said inclusion space via the said storage chamber. preferable. According to this, since the humidified air can be discharged to the inclusion space, even if the humid air cannot be sufficiently recovered when the air is moved from the inclusion space to the storage chamber, the air in the inclusion space is removed. High humidity can be achieved quickly.

  Moreover, in this invention, the said air storage means introduce | transduces the air which moved from the said inclusion space into the said storage chamber, and introduce | transduces the air of the said storage chamber into the said 1st humidification means. A second flow path that conducts, a third flow path that leads the air from the first humidification means to the inclusion space, and the inclusion that circulates air in a direction from the inclusion space toward the storage chamber A first check valve disposed between the space and the storage chamber, and the first humidifying means and the inclusion space for circulating air in a direction from the first humidification means toward the inclusion space. And a second check valve disposed between the two. According to this, when the pressure in the storage chamber decreases, the air from the inclusion space flows into the storage chamber through the first flow path by the action of the first and second check valves. Air can be prevented from flowing out from the first humidifying means to the internal space through the flow path. In addition, when the pressure in the storage chamber increases, the first and second check valves cause the air from the first humidifying means to flow out into the inclusion space through the third flow path, The air from the inclusion space can be prevented from flowing into the storage chamber through the flow path. Thereby, the structure which takes in the air of an internal space in a storage chamber, humidifies the air by a 1st humidification means, and discharges | emits it to an internal space is implement | achieved easily.

  In the present invention, it is preferable that the external communication channel is in communication with the atmosphere via a second humidifying means for humidifying the moving air. According to this, air flowing into the internal space from the outside is always humidified, so that highly humid air is reliably stored in the storage chamber.

  In the present invention, there is provided a valve that selectively takes an open state in which the external communication channel is opened to the outside and a closed state in which the external communication channel is closed, and the control means includes the valve It is preferable to switch the state. According to this, since it is possible to switch between a state in which air can be exchanged between the inclusion space and the outside and a state in which no air is exchanged as required, capping while smoothing the exchange of air between the inclusion space and the storage chamber The sealing property of the means can be improved.

  When the capping means is moved from the separation position to the covering position, moisture evaporates from the discharge port, but if the air in the internal space becomes saturated, drying in the discharge port does not proceed any further. However, if the capping means is moved from the covering position to the separation position after that, the humid air in the internal space is dissipated into the atmosphere, so even if the capping means is moved to the covering position again, Since the air in the enclosing space is as dry as the atmosphere, the water evaporates from the outlet. On the other hand, according to the present invention, the air moved from the inclusion space before the capping means is moved from the covering position to the separation position is returned to the inclusion space after the capping means is moved from the separation position to the covering position. . Therefore, the inside space is in a highly humid state and the liquid near the discharge port is prevented from drying. Further, since the liquid in the discharge port is not promoted to solidify, the amount of liquid to be preliminarily discharged can be suppressed, or the preliminary discharge itself can be made unnecessary.

1 is a schematic diagram schematically showing an internal configuration of an ink jet printer according to a first embodiment which is an embodiment of the present invention. 2A is a plan view of the capping unit, and FIG. 2B is a cross-sectional view taken along line BB of FIG. 2A, and includes an air tube and an air tank connected to the moving table. . It is a figure which shows a series of operation | movement of a head and a cap. It is a figure which shows the movement of the cap with respect to a head. The illustration of the piston moving mechanism is omitted. FIG. 5A is a plan view of the cap, and FIG. 5B is a front view of the cap. In 2nd Embodiment which is another one embodiment of this invention, it is a figure which shows a mode that air is attracted | sucked from the inclusion space of a cap. The illustration of the piston moving mechanism is omitted. FIG. 7 is a diagram showing how air is returned to the internal space of the cap in the configuration of FIG. 6. The illustration of the piston moving mechanism is omitted. In 3rd Embodiment which is another one embodiment of this invention, it is a figure which shows a mode that air is attracted | sucked from the inclusion space of a cap, or air is returned to the inclusion space of a cap. The illustration of the piston moving mechanism is omitted.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram showing an internal configuration of an ink jet printer (hereinafter, printer 1) according to a first embodiment which is an embodiment of the present invention. The printer 1 is a line type color ink jet printer having four ink jet heads 2 (hereinafter, heads 2).

  The printer 1 has a substantially rectangular parallelepiped casing 1a. A paper discharge unit 15 is provided on the top plate of the housing 1a. The internal space of the housing 1a can be divided into three spaces in order from the top. In the upper space and the middle space, a paper conveyance path that is continuous with the paper discharge unit 15 is configured. In the upper space, the sheet is transported and the image is formed on the sheet. In the middle space, the paper is stored and taken out. In the lower space, an ink supply source is accommodated, and ink is supplied to the corresponding inkjet head 2.

  In the upper space, four heads 2, a transport mechanism 16 that transports the paper, a guide unit that guides the paper, a capping unit 100 that protects the lower surface (discharge surface 2a) of the head 2, and the like are arranged. A control unit 99 that controls the operation of the entire printer including these mechanisms is disposed in the upper part of the upper space.

  The four heads 2 are long line heads in the main scanning direction (a direction orthogonal to the paper surface of FIG. 1), and have a substantially rectangular parallelepiped outer shape. The heads 2 are arranged at a predetermined pitch in the sub-scanning direction and are fixed to the head frame 9. The head frame 9 is supported from both sides in the sub-scanning direction by the head moving mechanism 20. The head moving mechanism 20 is controlled by the control unit 99 and moves the four heads 2 up and down together with the head frame 9.

  Hereinafter, the sub-scanning direction is a direction parallel to the transport direction when the paper P is transported in the transport unit 21, and the main scanning direction is a direction parallel to the horizontal plane and perpendicular to the sub-scanning direction. .

  A plurality of ejection openings are opened on the lower surface (ejection surface 2a) of each head 2. From each ejection surface 2a, magenta, cyan, yellow, and black inks are ejected during image formation. A discharge region 2c, which is a region where discharge ports are opened on the discharge surface 2a, is long in the main scanning direction (see FIG. 2).

  As shown in FIG. 1, the transport mechanism 16 includes a belt roller 6, 7 and an endless transport belt 8 wound between both rollers 6, 7, and a nip roller 4 disposed on the outside of the transport belt 8 and a peeling roller. The plate 5, the tension roller 10 disposed inside the conveyor belt 8, a rectangular parallelepiped platen 18, and the like.

  The belt roller 7 is a driving roller, and is rotated clockwise in FIG. At this time, the conveyor belt 8 travels along the thick arrow. The belt roller 6 is a driven roller and rotates clockwise in FIG. 1 as the transport belt 8 travels. The nip roller 4 is disposed so as to face the belt roller 6 and presses the paper P supplied from the preceding guide portion against the outer peripheral surface 8 a of the transport belt 8. The peeling plate 5 is disposed so as to face the belt roller 7, and peels the paper P from the outer peripheral surface 8a and guides it to the subsequent guide portion. The tension roller 10 urges the lower loop of the conveyor belt 8 toward the outside to remove the slack of the conveyor belt 8. The platen 18 is disposed to face the four heads 2 and supports the upper loop of the conveyor belt 8 from the inside. Thus, a predetermined gap suitable for image formation is formed between the outer peripheral surface 8a and the ejection surface 2a of the head 2.

  The guide portions are arranged on both sides of the transport mechanism 16. The upstream guide portion (front guide portion) includes two guides 13 a and 13 b and a pair of feed rollers 14. The guide unit connects a paper feeding unit 1 b (described later) and the transport mechanism 16. The downstream guide portion (rear guide portion) includes two guides 29 a and 29 b and two pairs of feed rollers 28. The guide unit connects the transport mechanism 16 and the paper discharge unit 15.

  As will be described later, the capping unit 100 covers the ejection surface 2a of the head 2 to prevent the ink in the ejection port from drying, and is disposed adjacent to the head 2 in the main scanning direction.

  A paper feed unit 1b is arranged in the middle space. The paper feed unit 1b has a paper feed tray 11 and a paper feed roller 12, and the paper feed tray 11 is detachably attached to the housing 1a. The paper feed tray 11 is a box that opens upward, and stores a plurality of papers P. The paper feed roller 12 feeds the uppermost paper P in the paper feed tray 11 and supplies it to the upstream guide unit.

  As described above, the paper transport path from the paper feed unit 1b to the paper discharge unit 15 via the transport mechanism 16 is formed by the upper space and the middle space. Based on the print command, the paper P fed from the paper feed tray 12 is supplied to the transport mechanism 16 via the upstream guide unit. When the paper P passes directly below each head 2 in the sub-scanning direction, ink is sequentially ejected from the ejection surface 2a, and a color image is formed on the paper P. The paper P is further conveyed through the downstream guide portion and discharged from the upper opening 22 to the paper discharge portion 15.

  In the lower space, the ink tank unit 1c is detachably attached to the housing 1a. Four ink tanks 17 are stored side by side in the ink tank unit 1c. Ink is supplied from each ink tank 17 to the corresponding head 2 via an ink tube (not shown).

  Hereinafter, the configuration of the capping unit 100 will be described in detail with reference to FIGS. 2 and 3. As shown in FIG. 2A, the capping unit 100 includes a moving table 101 having four caps 110 (capping means) fixed on the upper surface, and a moving table moving mechanism 102 that reciprocates the moving table 101 in the main scanning direction. And have. The moving table moving mechanism 102 moves the moving table 101 away from the head 2 in the main scanning direction (retracted position) shown in FIG. 3A and the position below the head 2 shown in FIG. Position).

  The cap 110 has a protrusion 111 that protrudes upward from the flat upper surface of the movable table 101. The projection 111 has a long upper side that is elongated along the four sides of the parallelogram along the main scanning direction in plan view, and has a flat upper end. The four protrusions 111 are arranged at the same pitch as the head 2 along the sub-scanning direction. When the movable table 101 is at the position shown in FIG. 3C, each protrusion 111 surrounds the ejection region 2c of the head 2 in a plan view as shown in FIG. The protrusion 111 is made of an elastic material such as rubber.

  In the acute corner of the protrusion 111, communication holes 112 and 113 that penetrate the movable table 101 in the vertical direction are formed. The communication hole 113 is located on the opposite side of the communication hole 112 in the diagonal direction of the parallelogram. As shown in FIG. 2B, one end of an air tube 121 (external communication channel) is connected to the opening on the lower surface side of the communication hole 112. The air tube 121 has a flexibility and a length that can follow the movement of the moving table 101 even if the moving table 101 moves. The other end of the air tube 121 is open to the atmosphere, and an on-off valve 122 is provided in the middle. The on-off valve 122 is controlled by the control unit 99 to be in a state where air flows through the air tube 121 (hereinafter referred to as an open state) and a state where the air tube 121 is closed and air cannot flow (hereinafter referred to as air flow). To be closed).

  One end of an air tube 123 (suction channel) is connected to the opening of the communication hole 113 on the lower surface of the moving table 101. The other end of the air tube 123 is connected to an air tank 124 (air storage means). Inside the air tank 124, a storage chamber 124a for storing air is formed. The air tube 123 has flexibility and length that can follow the movement of the moving base 101 even if it moves. The air tank 124 is configured in a cylinder shape, and a piston 125 (displacement member) is inserted from below. The piston 125 is connected to the piston moving mechanism 126. The piston moving mechanism 126 reciprocates the piston 125 in the direction toward the back of the storage chamber 124a and in the opposite direction. The control unit 99 controls the piston moving mechanism 126 to displace the piston 125, thereby changing the volume of the storage chamber 124a (the volume of air that can be stored in the storage chamber 124a).

  The control unit 99 moves the cap 110 and the head 2 by controlling the head moving mechanism 20 and the moving table moving mechanism 102. Accordingly, the control unit 99 moves the cap 110 relative to the head 2 as follows. When the ink is ejected from the head 2, the cap 110 is disposed at the position shown in FIG. At this time, the cap 110 is at a retracted position away from the head 2 in the main scanning direction. When the ink ejection is completed, the control unit 99 controls the head moving mechanism 20 to raise the head 2 as shown by the arrow X1 from the state of FIG. As a result, as shown in FIG. 3B, a gap is formed between the head 2 and the transport mechanism 16 so that the cap 110 and the movable table 101 can be inserted.

  Then, the control unit 99 controls the moving table moving mechanism 102 to horizontally move the moving table 101 along the arrow X2 to the facing position directly below the head 2 shown in FIG. Further, the control unit 99 controls the head moving mechanism 20 to lower the head 2 along the arrow X3 and bring the ejection surface 2a into contact with the upper end of the protrusion 111 as shown in FIG. As a result, the ejection region 2 c is surrounded by the protrusion 111 in a plan view and covered with the cap 110.

  As described above, the control unit 99 moves the cap 110 relative to the head 2, so that the control unit 99 moves away from the separated position (the positions in FIGS. 3A to 3C). It moves to the covering position (position of FIG. 3 (d)) that contacts the discharge surface 2a and covers the discharge region 2c. On the contrary, when the cap 110 is relatively moved from the covering position to the separation position, the control unit 99 moves the moving base 101 and the head 2 in the reverse order.

  When the cap 110 is in the covering position, an internal space 110 a is formed between the cap 110 and the ejection surface 2 a of the head 2. The internal space 110a is a space defined by the ejection surface 2a, the protrusion 111, and the upper surface of the movable table 101, as shown in FIG. At this time, since the discharge region 2c is covered with the internal space 110a, the discharge port is isolated from the outside air. Accordingly, once the interior space 110a is saturated due to the evaporation of moisture from the discharge port, the moisture does not evaporate any more.

  However, when the printing process is executed again, the cap 110 is separated from the covering position in a state where the humid air is accumulated in the inner space 110a, so that the air in the inner space 110a is moved out of the cap 110. Dissipate. Then, immediately after the printing process is finished and the cap 110 is moved to the covering position again, the air in the internal space 110a is dried to the same extent as the outside air. Therefore, even if the discharge region 2c is covered with the cap 110, moisture evaporation from the discharge port is inevitable until the air in the internal space 110a is saturated with water vapor. If the ejection port hardly ejects ink during the printing process, the ink in the ejection port may increase in viscosity to such an extent that the ejection characteristics are impaired by this moisture evaporation.

  Therefore, in the present embodiment, when moving the cap 110 when executing a printing process, the control unit 99 controls the piston moving mechanism 126 and the on-off valve 122 as follows. First, it is assumed that the cap 110 is in the covering position as shown in FIG. The interior space 110a is in a state where water vapor is saturated. At this time, the control unit 99 opens the on-off valve 122 and controls the piston moving mechanism 126 (not shown in FIG. 4) to move the piston 125 downward along the arrow X4. At this time, the volume of the storage chamber 124a increases. Along with this, the air in the internal space 110a flows into the storage chamber 124a through the air tube 123 as indicated by the arrow Y1. Thus, the piston 125 and the piston moving mechanism 126 constitute suction means for sucking air from the internal space 110a to the storage chamber 124a. On the other hand, on the side opposite to the communication hole 113 in the main scanning direction, external air flows through the air tube 121 into the internal space 110a along the arrows Y2 and Y3.

  Thus, before the cap 110 leaves | separates from a covering position, highly humid air is accommodated in the storage chamber 124a. Thereafter, even when the cap 110 is separated from the head 2 as shown in FIG. 4B, high-humidity air is stored in the storage chamber 124a. At this time, the storage amount of air in the storage chamber 124a may be at least equal to the volume occupied by the internal space 110a. In the present embodiment, the air tube 123 and the storage chamber are connected from the opening / closing valve 122 via the internal space 110a. The volume occupied by the flow path up to the connection with 124a is equal.

  Then, after the printing process is completed, when the cap 110 moves to the covering position again as shown in FIG. 4C, the control unit 99 opens the on-off valve 122. At the same time, the piston moving mechanism 126 is controlled to move the piston 125 upward along the arrow X5. Due to the movement of the piston 125, the volume of the storage chamber 124a decreases. Along with this, the air in the storage chamber 124a flows into the inclusion space 110a through the air tube 123 as indicated by an arrow Y4. On the other hand, on the side opposite to the connection side of the air tube 123 in the main scanning direction, the air in the internal space 110a flows out through the air tube 121 as indicated by arrows Y5 and Y6. When the piston 125 reaches the uppermost position, the control unit 99 closes the on-off valve 122. As described above, the high-humidity air stored in the storage chamber 124a is returned to the internal space 110a, and the open / close valve 122 prevents external air from entering the internal space 110a.

  By the way, when moving the air between the inclusion space 110a and the storage chamber 124a, if the moving speed of the piston 125 is too high, a turbulent flow is generated in the inclusion space 110a, and the air in the inclusion space 110a is agitated. There is a risk. In this case, for example, the outside air that has flowed into the internal space 110a is mixed with the high-humidity air that is present in the internal space 110a, so that the dry external air is easily mixed into the air stored in the storage chamber 124a. Alternatively, the high-humidity air returned to the internal space 110 a is mixed with the dry air in the internal space 110 a and easily leaks from the communication hole 112. Therefore, the control unit 99 of the present embodiment controls the piston moving mechanism 126 so that the piston 125 moves at such a speed that turbulent flow does not occur in the internal space 110a.

The following is an example for moving the piston 125 so that turbulent flow does not occur in the internal space 110a. In this embodiment, the width W of the internal space 110a shown in FIG. 5 (a) is 2.5 * 10 ⁻² m (25 mm), and the depth D of the internal space 110a shown in FIG. 5 (b) is 2 *. It is assumed that it is 10 ⁻³ m (2 mm). The Reynolds number that becomes the boundary between turbulent flow and laminar flow is set to 2300. At this time, when the velocity of the air flow in the inclusion space 110a is U [m / s], and the kinematic viscosity ν of air when the air temperature is 20 ° C. is 1.0 * 10 ⁻⁶ m ² / s, Since the Reynolds number Re = U * D / ν holds, U = 2300 * 1.0 * 10 ⁻⁶ / (2 * 10 ⁻³ ) = 1.15 [m / s]. In addition, since the cross-sectional shape of the central part of the inclusion space 110a orthogonal to the direction of the airflow is a rectangle of horizontal (W) 2.5 * 10 ⁻² m and vertical (D) 2 * 10 ⁻³ m, the representative length The thickness was set to D = 2 * 10 ⁻³ m. The suction flow rate Q from the communication hole 113 corresponding to the air velocity U = 1.15 [m / s] is Q = U * D * W = 1.15 * 2.5 * 10 ⁻² * 2 * 10. ⁻³ = 5.75 * 10 ⁻⁵ m ³ /s=57.5 ml / s.

  Therefore, in this embodiment, when the piston 125 is moved so that the flow rate of the air moving between the storage chamber 124a and the internal space 110a through the communication hole 113 is less than 57.5 ml / s, the internal space 110a Therefore, no turbulent flow will occur. Actually, it is affected by turbulent flow due to the difference in the representative length and the difference in the Reynolds number that becomes the boundary between turbulent flow and laminar flow. However, most of the high-humidity air is stored in the storage chamber 124a. Or can be filled into the internal space 110a. In order to further suppress the influence of turbulent flow, it is more preferable to move the piston 125 at a speed sufficiently lower than the speed at which the air flow rate through the communication hole 113 is less than 57.5 ml / s. At this time, the speed of the piston 125 may be set based on a measured value of a speed at which turbulent flow does not occur reliably in the internal space 110a.

  According to the first embodiment described above, the air in the internal space 110a is sucked into the storage chamber 124a before the cap 110 is moved from the covering position to the separation position. Thereby, the highly humid air in the internal space 110a is temporarily retracted to the storage chamber 124a. Then, after the cap 110 is again moved to the covering position, the humid air in the storage chamber 124a is quickly returned to the inclusion space 110a. Thereby, while the discharge surface 2a is protected by the cap 110, the evaporation of moisture from the ink in the discharge port to the internal space 110a is suppressed. Since the thickening at the discharge port is difficult to proceed, the discharge characteristic of each discharge port is maintained for a long time. Even if a forced recovery process is required, it is possible to reduce the amount of ink that is wasted.

  Further, the projection 111 of the cap 110 has a parallelogram shape in plan view, and a communication hole 112 is disposed near one of the two acute angles of the parallelogram, and a communication hole 113 is disposed near the other. Has been. Thereby, with respect to the internal space 110a, it is possible to smoothly suck in high-humidity air from one side while introducing outside air from the other side. Further, the communication holes 112 and 113 are disposed within the acute angle of the parallelogram. That is, the internal space 110a is tapered toward the communication holes 112 and 113. For this reason, air can be smoothly circulated toward the communication holes 112 and 113 without causing air retention in the internal space 110a, and air can be smoothly introduced from the communication holes 112 and 113. it can.

  Further, as in the above-described embodiment, the air is circulated so that no turbulent flow is generated in the internal space 110a, so that it is possible to suppress mixing of the external air and the air in the internal space 110a. For this reason, when the high-humidity air in the internal space 110a is sucked into the storage chamber 124a, external air is less likely to be mixed into the sucked air, and the high-humidity air that has been retreated into the storage chamber 124a is returned to the internal space 110a. At this time, it becomes difficult for high-humidity air to leak out.

(Second Embodiment)
The second embodiment, which is another embodiment of the present invention, will be described below. The difference between the second embodiment and the first embodiment is only the configuration related to the capping unit. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  The capping unit 200 of the second embodiment has a cap 110 and an air tube 121 connected to the communication hole 112 as shown in FIG. The air tube 121 is provided with an on-off valve 122, and the control unit 99 controls the on-off valve 122 so that the air tube 121 is opened to the outside and the air tube 121 is closed. Can be switched.

  An air tank 224 is connected to the communication hole 113 via an air tube 223 (first flow path). The internal space 110 a and the storage chamber 224 a in the air tank 224 communicate with each other through the air tube 223. The air tank 224 is configured in a cylindrical shape like the air tank 124, and a piston 125 is inserted from below. The piston 125 is connected to a piston moving mechanism 126 (not shown in FIGS. 6 and 7), and is reciprocated by the piston moving mechanism 126 in the direction toward the back of the storage chamber 124a and in the opposite direction.

  A check valve 231 is provided at a communication portion between the air tube 223 and the storage chamber 224a. The check valve 231 is pressed against the communicating portion by an urging member (not shown) and blocks the communicating portion (see FIGS. 6A and 7A). Here, when the pressure on the air tube 223 side becomes larger than the pressure on the storage chamber 224a side by a predetermined magnitude, the pressure difference acting on the check valve 231 exceeds the urging force of the urging member, and the check valve 231 is stored. It moves to the chamber 224a side. Thereby, a communication part is open | released and it will be in the state which the air tube 223 and the storage chamber 224a connected (refer FIG.6 (b)).

  The air tank 224 is connected to a humidifying tank 226 (first humidifying means), which is another tank, via an air tube 227 (second flow path). The storage chamber 224a communicates with the humidification chamber 226a in the humidification tank 226 through the air tube 227. Water Wt is stored in the humidification chamber 226a. The lower end of the air tube 227 is disposed below the water surface. Therefore, the air that has flowed from the air tank 224 into the humidification tank 226 via the air tube 227 is first humidified through the water.

  The humidification tank 226 is also connected to the middle part of the air tube 223 via the air tube 228 (third flow path). The humidification chamber 226 a communicates with the air tube 223 through the air tube 228. A check valve 232 is provided at a communication portion between the air tube 223 and the air tube 228. The check valve 232 is pressed against the communicating portion by an urging member (not shown) and blocks the communicating portion (see FIGS. 6A to 7A). Here, when the pressure on the air tube 228 side becomes larger than the pressure on the air tube 223 side by a predetermined magnitude, the pressure difference acting on the check valve 232 exceeds the urging force of the urging member, and the check valve 232 Move to the tube 223 side. As a result, the communication portion is opened, and the air tube 223 and the air tube 228 are in communication (see FIG. 7B).

  In the present embodiment, the control unit 99 controls the piston moving mechanism 126 and the on-off valve 122 as follows. First, as shown in FIG. 6A, it is assumed that the cap 110 is in the covering position, and the internal space 110a is humid from the outside, for example, the amount of water vapor is saturated. From this state, the control unit 99 opens the on-off valve 122 and controls the piston moving mechanism 126 to move the piston 125 downward along the arrow X6 in FIG. As a result, the pressure in the storage chamber 224a decreases to a predetermined magnitude, the check valve 231 moves toward the storage chamber 224a, and the air tube 223 and the storage chamber 224a communicate with each other. Along with this, the air in the internal space 110a flows into the storage chamber 224a through the air tube 223 as indicated by an arrow Y6. On the other hand, the air from the outside flows into the inclusion space 110a along the air tube 121 along the arrows Y7 and Y8.

  While the piston 125 moves downward, the pressure in the air tube 228 is less than or at most about the same as in the air tube 223. For this reason, the check valve 232 remains in a state where the communication portion is blocked. Therefore, only the air flowing in from the internal space 110a is accommodated in the storage chamber 224a.

  When the control unit 99 stops the movement of the piston 125, the pressure difference between the air tube 223 side and the storage chamber 224a side becomes small, and the check valve 231 eventually blocks the communication part between them. Accordingly, as shown in FIG. 7A, the air in the storage chamber 224a is held by the check valves 231 and 232 so as not to leak to the outside. In this state, the control unit 99 moves the head 2 upward from the covering position and moves the cap 110 to the retracted position.

  Thereafter, as shown in FIG. 7B, when the cap 110 is again in the covering state, the control unit 99 quickly opens the on-off valve 122 and controls the piston moving mechanism 126 to move the arrow. The piston 125 is moved upward along X7. Accordingly, the pressure in the storage chamber 224a increases, so that the check valve 231 maintains the state where the communication portion is sealed, while the air in the storage chamber 224a is air tube 227 as indicated by arrows Y9 and Y10. Flows into the humidification chamber 226a. The air that has flowed into the humidifying chamber 226a is humidified through the water, and further flows into the air tube 228 along the arrow Y11. Thereby, since the pressure in the air tube 228 increases to a predetermined magnitude, the check valve 232 moves to the air tube 223 side, and the humidified air flows into the air tube 223. Further, the humidified air flows out from the air tube 223 to the internal space 110a as indicated by an arrow Y12. On the other hand, the air in the internal space 110a flows out of the air tube 121 along the arrows Y13 and Y14. When the piston 125 reaches the uppermost position, the control unit 99 closes the on-off valve 122.

  While the piston 125 moves upward, the pressure in the air tube 223 is lower than that in the storage chamber 224a or at most the same pressure. For this reason, the check valve 231 remains in a state where the communication portion is blocked. Therefore, the humidified air is reliably filled in the internal space 110a.

  According to the second embodiment described above, after the air in the internal space 110a is taken into the storage chamber 224a, the air is humidified through the humidification tank 226 before returning to the internal space 110a. Therefore, sufficiently humidified air can be returned to the internal space 110a.

(Third embodiment)
Hereinafter, a third embodiment, which is still another embodiment of the present invention, will be described. The difference between the third embodiment and the first embodiment is only the configuration related to the capping unit. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  As shown in FIG. 8A, the capping unit 300 of the third embodiment includes a cap 110, an air tank 124 and a piston 125 connected to the communication hole 113 through the air tube 223. The piston 125 is connected to a piston moving mechanism 126 (not shown in FIG. 8).

  A humidification tank 326 (second humidification means) is connected to the communication hole 112 via an air tube 321. Water Wt is stored in the humidification chamber 326a. The internal space 110a and the humidification chamber 326a communicate with each other through the air tube 321. The humidification chamber 326a can communicate with the outside through the air tubes 327 and 328. The lower end of the air tube 327 is disposed below the water surface in the humidification chamber 326a, but the lower end of the air tube 328 is not inserted into the humidification chamber 326a. The air tubes 327 and 328 are provided with check valves 331 and 332. The check valve 331 circulates air only in the direction from the outside through the air tube 327 toward the humidification chamber 326a. The check valve 332 circulates air only in the direction from the humidification chamber 326a to the outside through the air tube 328.

  In this configuration, as shown in FIG. 8A, when the control unit 99 controls the piston moving mechanism 126 and moves the piston 125 downward along the arrow X8, the air in the inclusion space 110a is changed to the arrow Y15. And flows into the storage chamber 124a. Thereby, the humid air in the internal space 110a is accommodated in the storage chamber 124a. From the humidification chamber 326a, the humidified air flows into the inclusion space 110a along the arrow Y16. Even in a mode in which the air from the humidification chamber 326a flows into the storage chamber 124a, the humidity of the air in the storage chamber 124a hardly decreases because there is no mixing of dry outside air. At this time, outside air flows into the humidifying chamber 326a from the air tube 327 instead of the air that flows out to the internal space 110a. Even if the outside air is dry, it is humidified when it flows into the humidification chamber 326a, so that only the humidified air is accommodated in the storage chamber 124a.

  Thereafter, when the cap 110 is separated from the head 2 and returns to the covering state again, the control unit 99 controls the piston moving mechanism 126 and moves the piston 125 upward along the arrow X9 in FIG. Move. Thereby, the high-humidity air evacuated to the storage chamber 124a returns to the inclusion space 110a as indicated by an arrow Y18. The air in the internal space 110a flows into the humidification chamber 326a along the arrow Y19. The air in the humidification chamber 326 a flows out from the air tube 328 to the outside by the action of the check valves 331 and 332, but does not flow out from the air tube 327. The air in the humidification chamber 326a flows out easily without passing through the water. Therefore, the ink meniscus formed at the ejection port is not destroyed.

  According to the third embodiment described above, when the humid air in the internal space 110a is sucked into the storage chamber 124a, external air is once humidified and then flows into the internal space 110a. That is, since external air is always humidified when it flows into the internal space 110a, high-humidity air is reliably stored in the storage chamber 124a.

<Modification>
The above is a description of a preferred embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the means for solving the problem. It is possible.

  For example, in the above-described embodiment, air is moved between the external space and the internal space 110a at the same time as the air is moved between the internal space 110a and the storage chamber 124a. The “external air” in this case may be outside air or air in another air tank. In short, it is sufficient that air is exchanged between the internal space 110a and the external of the internal space 110a.

  In the above-described embodiment, the piston 125 is moved to suck the air in the internal space 110a into the storage chamber 124a and the like. However, the movement of air to the storage chamber 124a may be performed by pressurization. For example, by connecting a pressurizing cylinder or pump to the communication hole 112 side and thereby sending air from the communication hole 112 side to the internal space 110a, the air is moved from the communication hole 113 on the opposite side to the storage chamber 124a. You may let them. Further, air in the internal space 110a may be sucked into the storage chamber 124a using a suction pump instead of the piston 125. In addition, when moving air to the storage chamber 124a by pressurization, compared with the case where air is moved to the storage chamber 124a by suction | attraction, external air tends to mix in the air in the inclusion space 110a. For this reason, it is good to send air through a humidification chamber.

  In the above-described embodiment, the cap movement that moves the cap 110 relative to the head 2 by the head moving mechanism 20 that moves the head 2 in the vertical direction and the moving table moving mechanism 102 that moves the moving table 101 in the horizontal direction. Means are configured. However, any specific configuration for moving the cap 110 relative to the head 2 may be used. For example, the head 2 may be configured to move only the cap 110 while being fixed, or vice versa. Further, a moving mechanism that horizontally moves the head 2 and a moving mechanism that vertically moves the cap 110 may be provided.

  The configurations of the first to third embodiments can be combined with each other. For example, only one of the humidification tank 226 and the humidification tank 326 of the second and third embodiments is provided in each embodiment, but both may be provided as the same embodiment. Further, the check valve of the second embodiment or the third embodiment may be appropriately provided in the first embodiment.

  Further, in the above-described embodiment, the open / close valve 122 is provided in the air tube 121 that allows the internal space 110a to communicate with the outside, and the open state and the closed state are switched. However, the internal space 110a may always be opened to the outside through the labyrinth flow path.

  In the above-described embodiment, if the cap 110 is elongate in the main scanning direction and tapered toward the communication holes 112 and 113 disposed at both ends in the main scanning direction, for example, the parallel four sides as described above are used. It does not have to be a shape.

  Moreover, although the above-mentioned embodiment is an example which applied this invention to the inkjet head which discharges an ink from a nozzle, the object which can apply this invention is not restricted to such an inkjet head. The present invention can be applied to any recording head that discharges a liquid containing water as a component.

1 Printer 2 Inkjet head (head)
2a Discharge surface 2c Discharge area 20 Head moving mechanism 99 Control unit 110 Cap 110a Inner space 122 Open / close valve 125 Piston 100, 200, 300 Capping unit 124, 224 Air tank 124a, 224a Storage chamber 226, 326 Humidification tank 231, 232 Check valve

Claims (10)

A recording head having a discharge surface on which a discharge port for discharging a liquid containing water as a component is formed;
Capping means for covering the discharge area where the discharge port is formed in contact with the discharge surface;
Cap movement for moving the capping means relative to the recording head between a covering position that is in contact with the discharge surface and covers the discharge area and a separation position that is spaced apart from the discharge surface and opens the discharge area Means,
An external communication channel that communicates the internal space formed between the capping unit and the discharge surface with the outside when the capping unit is in the covering position;
An air storage means that has a storage chamber for storing air, and moves air between the internal space and the storage chamber;
Before the capping means starts to move from the covering position to the separation position, air is allowed to flow from the internal space into the storage chamber, and after the capping means has moved from the separation position to the covering position, A recording apparatus comprising: a cap moving means and a control means for controlling the air storage means so that air in the storage chamber flows into the internal space.   The recording apparatus according to claim 1, wherein the air storage unit includes a suction unit that sucks air from the internal space when air flows into the storage chamber. The discharge region is elongated in one direction;
The air storage means has a suction channel for introducing air sucked from the inclusion space into the storage chamber;
A communication portion between the suction flow path and the inclusion space is disposed in the vicinity of one end of the inclusion space with respect to the one direction, and a communication portion between the external communication flow path and the inclusion space with respect to the one direction. The recording apparatus according to claim 2, wherein the recording apparatus is disposed near the other end of the space.   The recording apparatus according to claim 3, wherein the internal space is tapered toward the one end and is tapered toward the other end.   The said control means controls the said air storage means so that the air of the said inclusion space may be attracted | sucked at the speed | rate which a turbulent flow does not generate | occur | produce, The any one of Claims 2-4 characterized by the above-mentioned. Recording device.   The recording apparatus according to claim 2, wherein the air storage unit includes a displacement member that changes a volume of the storage chamber by being displaced in the storage chamber.   The said air storage means has a 1st humidification means to humidify the air moved from the said inclusion space until it returns to the said inclusion space via the said storage chamber, The 1st humidification means characterized by the above-mentioned. The recording apparatus according to any one of 6. The air storage means
A first flow path for introducing air that has moved from within the inclusion space into the storage chamber;
A second flow path for introducing the air in the storage chamber into the first humidifying means;
A third flow path for leading air from the first humidifying means to the internal space;
A first check valve disposed between the internal space and the storage chamber for circulating air in a direction from the internal space toward the storage chamber;
Having a second check valve disposed between the first humidifying means and the inclusion space for circulating air in a direction from the first humidification means toward the inclusion space. The recording apparatus according to claim 7, characterized in that:   The recording apparatus according to claim 1, wherein the external communication channel is in communication with the atmosphere through a second humidifying unit that humidifies the moving air. A valve is provided that selectively takes an open state in which the external communication channel is opened to the outside and a closed state in which the external communication channel is closed;
The recording apparatus according to claim 1, wherein the control unit switches a state of the valve.

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