JP6468032B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection apparatus.

  As a conventional liquid ejection device, for example, a fluid ejection device shown in Patent Document 1 has been proposed. In the fluid ejecting apparatus, a groove is provided inside the cap member, and a negative pressure pump is connected to the groove. In this maintenance, the cap member is sucked by the suction pump in contact with the ejection surface of the ejection head, and the ink is discharged from the ejection head into the cap member. Then, the cap member is sucked by the suction pump while the atmosphere is taken into the cap member, and the ink accumulated in the cap member is discharged. Then, the groove of the cap member is sucked by the negative pressure pump to remove the ink attached to the gap between the inside of the edge of the cap member and the ejection surface of the ejection head.

Japanese Patent No. 5310093

  In the fluid ejecting apparatus disclosed in Patent Literature 1, it is not possible to remove the ink remaining between the outer side of the edge of the cap member and the ejecting surface of the ejecting head by the negative pressure pump. For this reason, the remaining ink solidifies on the ejection surface and remains on the ejection surface as ink marks. In this case, when the cap member is brought into contact with the ejection surface of the ejection head, a part of the cap member may come into contact with the ink mark, and a gap may be generated between the ejection surface of the ejection head and the cap member. When the inside of the cap member is sucked, air enters from the gap, and ink of the ejection head cannot be sufficiently discharged, leading to problems such as defective ink discharge.

  The present invention has been made to solve such a problem, and provides a liquid ejecting apparatus capable of suppressing problems caused by liquid traces formed at locations corresponding to the edge of the cap on the head surface. It is aimed.

  A liquid ejection apparatus according to an aspect of the present invention includes a head having a head surface in which an opening is formed at a downstream end of a flow path through which liquid or gas in the liquid flows, and for opening and closing the flow path. A cap having a bottom surface portion that can face the head surface, and a contact portion standing on the head side from the bottom surface portion, wherein the contact portion contacts the head surface and A cap capable of covering the head surface so as to form an internal space adjacent to the opening, and a contact for moving at least one of the head and the cap so that the cap contacts and separates from the head surface. A separation unit, a pressure adjustment unit that changes the pressure in the internal space, and a control unit that controls the valve, the contact / separation unit, and the pressure adjustment unit, and the control unit closes the valve, The cap is placed on the head surface. In a state where the pressure adjusting unit is in contact, the pressure adjusting unit reduces the pressure of the internal space, deforms the contact part inward than before pressure reduction, and contacts the head surface, and after the pressure reducing process A communication process in which the internal space and the external space are communicated by the pressure adjusting unit while the valve is closed and the cap is deformed and brought into contact with the head surface inward. After the communication process, with the cap held in contact with the head surface, the valve is opened, the internal space is decompressed again, and the liquid or the gas is discharged from the flow path. , Is configured to execute.

  According to this configuration, the abutting portion of the cap is deformed inward by the decompression process so as to abut on the head surface. Thereby, even if the liquid trace which the liquid solidified is formed in the location corresponding to the outside of the cap of the head surface, the contact portion is brought into contact with the area of the head surface where the liquid trace inside the liquid trace is not formed. be able to. For this reason, it is possible to improve the adhesion between the contact portion and the head surface and prevent a gap from being generated between the contact portion and the head surface. Thereafter, the state in which the cap is in contact with the head surface is maintained in the communication process and the discharge process. Therefore, while the abutting portion is in contact with the head surface inside the liquid trace, the liquid or gas is prevented from being generated by the liquid trace between the abutting portion and the head surface during the discharging process. It can be discharged sufficiently.

  The present invention has the configuration described above, and has an effect that it is possible to provide a liquid ejecting apparatus that can suppress problems caused by liquid marks formed at locations corresponding to the edges of the cap on the head surface. .

  The above object, other objects, features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

It is a figure which shows schematically the liquid discharge apparatus which concerns on Embodiment 1 of this invention. FIG. 2 is a block diagram illustrating a functional configuration of the liquid ejection apparatus in FIG. 1. It is a figure which shows the head surface of FIG. 1 schematically. It is a figure which shows the head surface of FIG. 1 schematically. FIG. 4 is a cross-sectional view schematically showing the head and the exhaust cap of FIG. 3. It is a perspective view which shows the exhaust cap of FIG. It is sectional drawing which shows the exhaust cap cut | disconnected along the AA line of FIG. It is a flowchart which shows an example of the maintenance operation | movement of a liquid discharge apparatus. 9A is a diagram schematically illustrating a state in which the cap lip is brought into contact with the exhaust surface in the decompression process, and FIG. 9B is a diagram illustrating a state in which the internal space of the cap is decompressed in the decompression process. These are figures which show the state of a communication process, and FIG. 9D is a figure which shows the state of a discharge process. It is a block diagram which shows the functional structure of the liquid discharge apparatus which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted.

(Embodiment 1)
First, a functional configuration of the liquid ejection apparatus 10 will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram schematically showing a liquid ejection apparatus 10 according to the first embodiment. FIG. 2 is a block diagram illustrating a functional configuration of the liquid ejection apparatus 10. In the following, a printer that ejects ink will be described as an example of the liquid ejecting apparatus 10, but the liquid ejecting apparatus 10 is not limited to a printer as long as it is a liquid ejecting apparatus 10 that ejects liquid.
The liquid ejection device 10 is a device that ejects liquid. This liquid is composed of a solvent and a solute, and examples thereof include pigment ink and dye ink. Solutes include, for example, not only those dissolved in a solvent such as dyes but also those dispersed in a solvent such as pigments. The liquid ejection apparatus 10 includes a head unit 20, a maintenance unit 30, and a control unit 40. The liquid ejection device 10 may further include a paper feed mechanism 11, a platen 12, and a transport mechanism 14. The head unit 20 includes a head 21 and a carriage 22 that holds and conveys the head 21.

The paper feed mechanism 11 is a mechanism that supplies the paper 19 in a paper feed tray (not shown) to the transport path. The platen 12 is a table on which the supplied paper 19 is placed.
The carriage 22 is a transport unit that reciprocates the head 21 in the scanning direction. For example, the carriage 22 is supported by two guide rails 122 extending in the scanning direction, and reciprocates in the scanning direction along the guide rails 122. The carriage 22 moves over an area (recording area) facing the platen 12 and an area (maintenance area) adjacent to the storage area along the scanning direction. In the storage area, the carriage 22 is arranged above the platen 12 and parallel to the platen 12 with a space therebetween.

For example, four sub tanks 125 are mounted on the carriage 22. These sub tanks 125 are arranged side by side along the scanning direction, and are connected to the tube joint 125a. The sub tank 125 is connected to the ink cartridge 125c by a flexible tube 125b through a tube joint 125a. The four ink cartridges 125c store four colors of ink, for example, magenta, cyan, yellow, and black.
Further, an exhaust unit 126 for discharging gas (air) staying in the sub tank 125 is connected to the sub tank 125. Details of the exhaust unit 126 will be described later.

The head 21 is a portion that discharges liquid such as ink from the nozzle hole of the nozzle 25, and is attached to the lower portion of the carriage 22 so that the nozzle hole faces the platen 12 in the storage area. The plurality of nozzles 25 are arranged in the transport direction orthogonal to the scanning direction, and form a nozzle row. For example, four nozzle rows are arranged in the scanning direction.
The transport mechanism 14 is a mechanism for transporting the paper 19 supplied from the paper feed tray to the paper discharge tray (not shown) through the platen 12 and the head 21, and this transport direction is orthogonal to the scanning direction. . For example, two transport rollers 114 are used as the transport mechanism 14. The two transport rollers 114 are arranged on the upstream side and the downstream side in the transport direction of the carriage 22 and rotate in the transport direction with the scanning direction as the axial direction.

  The maintenance unit 30 is a unit that performs various maintenance operations for maintaining and recovering the liquid ejection performance of the head 21 and is disposed in the maintenance area. The maintenance unit 30 includes an exhaust cap 31, a contact / separation part 32, a pressure adjustment part 33, an exhaust valve 34, and a wiper member 35. These will be described later. The maintenance unit 30 may have a waste liquid tank 30a.

  The control unit 40 includes a calculation unit (not shown) and a storage unit (not shown). The calculation unit is configured by a processor or the like, and the storage unit is configured by a memory accessible by the calculation unit. Each part of the liquid ejection apparatus 10 is controlled by the arithmetic part executing the program stored in the storage part.

  Next, the recording (printing) operation of the liquid ejection apparatus 10 will be described with reference to FIGS. 1 and 2. This operation is executed by the control unit 40. During printing, the paper 19 is supplied from the paper feed tray by the paper feed mechanism 11, placed on the platen 12, and further intermittently conveyed in the conveyance direction by the conveyance mechanism 14. The head 21 discharges liquid from the nozzle holes while moving in the scanning direction by the carriage 22. A desired image, characters, or the like is printed on the paper 19 by this liquid.

Next, the configuration of the head unit 20 will be described with reference to FIGS. 1 and 3 to 5. FIG. 3 is a bottom view schematically showing the head surface of the head unit 20. FIG. 4 is a cross-sectional view schematically showing the head unit 20 and the exhaust cap 31 cut in the scanning direction. FIG. 5 is a cross-sectional view schematically showing the head unit 20 and the exhaust cap 31 cut in the transport direction.
As shown in FIG. 4, the internal space of the sub tank 125 is used as the ink storage chamber 124. The ink storage chamber 124 communicates with the ink cartridge 125c (FIG. 1) via a flexible tube 125b connected to the tube joint 125a (FIG. 1). Thus, ink is stored in the ink storage chamber 124.
An ink supply hole 125d is formed at the bottom of the sub tank 125, and the ink storage chamber 124 communicates with the nozzle 25 (FIG. 3) of the head 21 through the ink supply hole 125d. Therefore, the ink in the ink storage chamber 124 is temporarily stored in the ink storage chamber 124 and then supplied to the head 21 from the ink supply hole 125d.

  A gas (air) mixed in the liquid flow path stays in the upper part of the ink storage chamber 124. This liquid flow path is a flow path for supplying a liquid to the head 21 and includes a flexible tube 125 b and an ink storage chamber 124 of the sub tank 125. The ink storage chamber 124 is used as a gas storage chamber that stores the gas in the liquid flow path.

  An exhaust hole 125e is formed in the upper part of the sub tank 125, and the ink storage chamber 124 communicates with the exhaust flow path 26 of the exhaust unit 126 through the exhaust hole 125e. Details of the exhaust unit 126 will be described later.

  As shown in FIGS. 3 to 5, the head 21 is, for example, a rectangular plate-like body, and the head 21 is provided with a number of nozzles 25 and a plurality of exhaust passages 26. The nozzle 25 is a flow path through which liquid flows, and the exhaust flow path 26 is a flow path through which gas in the liquid flows. One surface (head surface) of the head 21 is constituted by a nozzle surface 23 and an exhaust surface 24. An opening (nozzle hole) located at the downstream end of the nozzle 25 is formed in the nozzle surface 23, and an opening (exhaust hole) located at the downstream end of the exhaust passage 26 is formed in the exhaust surface 24. This exhaust port is an opening that leads to and discharges gas. The nozzle surface 23 and the exhaust surface 24 are provided on the same plane.

  The exhaust surface 24 has a property (high wettability) with higher affinity for the liquid than the surface (contact surface) that contacts the exhaust surface 24 of the exhaust cap 31. The exhaust surface 24 is formed on the carriage 22. When the wiper member 35 starts to wipe the nozzle surface 23, the wiper member 35 comes into contact with the left side surface of the carriage 22, and the liquid remaining on the wiper member 35 adheres to the left side surface of the carriage 22. The carriage 22 is formed of a material having a high affinity for the liquid so that the adhered liquid does not fall on the paper 19 when printing on the paper 19 (FIG. 1). For example, the exhaust surface 24 is formed of a material and surface roughness that have a lower surface tension than the cap. For example, the exhaust cap 31 is formed of silicon rubber so that the sliding load with the shaft 36b (see FIG. 5) is reduced, whereas the exhaust surface 24 is formed of ABS / PBT resin filled with glass fiber. ing. In addition, the surface roughness of the exhaust surface 24 is rougher than the contact surface of the exhaust cap 31. As described above, since the wettability of the exhaust surface 24 is high, the liquid attached to the exhaust surface 24 is difficult to be separated. Therefore, the liquid adhering to the exhaust surface 24 at the time of printing does not easily fall on the paper 19, and the liquid 19 is prevented from being soiled by this liquid.

  The nozzle 25 includes, for example, three color ink nozzles 25c, 25m, and 25y and a black ink nozzle 25b. Examples of the three color ink nozzles include a cyan ink nozzle 25c, a magenta ink nozzle 25m, and a yellow ink nozzle 25y. The nozzles 25 are arranged in the scanning direction from the exhaust passage 26 side in the order of a cyan ink nozzle 25c, a magenta ink nozzle 25m, a yellow ink nozzle 25y, and a black ink nozzle 25b. The same color ink nozzles 25c, 25m, 25y, and 25b are arranged in the transport direction. The upstream end of the nozzle 25 is connected to an ink tank (not shown). The pitch and number of the nozzles 25 in the transport direction are set as appropriate according to the resolution of the image. The number of rows of nozzles 25 in the scanning direction may be increased or decreased according to the number of colors of color ink.

  In this embodiment, four exhaust passages 26 are provided according to the number of colors of ink, and are arranged in the transport direction. As shown in FIG. 5, the upstream end of the exhaust passage 26 is connected to the ink storage chamber 124 via the exhaust hole 125 e of the sub tank 125. The black ink exhaust channel 26, the yellow ink exhaust channel 26, the magenta ink exhaust channel 26, and the cyan ink exhaust so that the black ink exhaust channel 26 is located downstream in the transport direction. The exhaust passages 26 are arranged in this order in the transport direction. The exhaust passage 26 is composed of an upper passage, a central passage, and a lower passage. In the direction perpendicular to the vertical direction, the area of the central flow path is larger than the upper flow path and the lower flow path. For this reason, the central channel is provided with an upper surface and a lower surface, the upper surface is provided with an opening to which the upper channel is connected, and the lower surface is provided with an opening to which the lower channel is connected. A valve (exhaust valve) 34 for opening and closing the exhaust passage 26 is provided in the internal space of the central passage.

  The exhaust valve 34 includes, for example, a valve body 34a, an O-ring 34b, a spring 34c, and a shaft 36b. The details of the shaft 36b will be described later.

  The valve body 34 a is a member that is provided in the exhaust flow path 26 and is always closed so as to be movable in the exhaust flow path 26. The valve body 34a has, for example, a disk shape and is provided so as to be movable in the vertical direction in the exhaust passage 26. A rod 34d is connected to the lower surface of the valve body 34a. The rod 34d is a rod-shaped member and extends in the vertical direction in the lower flow path.

  The O-ring 34b is a seal member that seals the exhaust flow path 26, and is provided so as to surround the opening on the lower surface of the central flow path. The spring 34c is a member that urges the valve body 34a downward, and is disposed between the upper surface of the central flow path and the upper surface of the valve body 34a.

  When the valve body 34a is pushed downward by the spring 34c, the valve body 34a is pressed against the lower surface of the central flow path via the O-ring 34b, and the O-ring 34b is pressed against the lower surface of the valve body 34a and the lower surface of the central flow path. Fill the gap between. Thereby, gas does not flow between the central flow path and the lower flow path via the opening on the lower surface of the central flow path, and the exhaust valve 34 closes the exhaust flow path 26. On the other hand, when the rod 34d is pushed up by a shaft to be described later, the valve body 34a rises and leaves the O-ring 34b. As a result, gas flows between the central flow path and the lower flow path via the opening on the lower surface of the central flow path, and the exhaust valve 34 opens the exhaust flow path 26.

  Next, the configuration of the maintenance unit 30 will be described with reference to FIGS. FIG. 6 is a perspective view showing the exhaust cap 31. FIG. 7 is a cross-sectional view of the exhaust cap 31 cut along the line AA in FIG. 7 shows a cross-sectional view of the long side surface portion, but the short side surface portion has the same cross-sectional shape as the long side surface portion except for the thickness of the side surface and the presence or absence of the fixing portion 31g. Therefore, description of the cross-sectional shape of the short side surface portion is omitted.

  As shown in FIG. 6, the exhaust cap 31 is a cap that can cover the exhaust surface 24, and is made of, for example, elastic rubber so as to be in close contact with the exhaust surface 24. The exhaust cap 31 has a box shape, and includes a bottom surface portion 31a and side surface portions 31b and 31c rising from a peripheral portion of the bottom surface portion 31a. A recess is formed by the inner surface of the bottom surface portion 31 a and the inner surfaces of the side surface portions 31 b and 31 c, and a space (inside the recess) surrounded by the recess is provided inside the exhaust cap 31. The concave portion has an opening portion opened upward, and thereby the inside of the concave portion is a space opened upward.

  In this embodiment, the bottom surface portion 31a is rectangular and has two short sides and two long sides. For example, four insertion holes 31d and one suction hole 31e are provided through the bottom surface portion 31a. These insertion holes 31d and suction holes 31e are arranged in the transport direction.

  The side surface portion includes two short side surface portions 31b and two long side surface portions 31c. The short side surface portion 31b is a side surface that rises from the short side of the bottom surface portion 31a and extends in the scanning direction. The long side surface portion 31c is a side surface that rises from the long side of the bottom surface portion 31a and extends in the transport direction. The rigidity of the short side surface portion 31b with respect to the external force in the transport direction is lower than the rigidity with respect to the external force in the scanning direction of the long side surface portion 31c. For example, as a configuration therefor, the direction parallel to the long side of the bottom surface portion 31a (this In the embodiment, the thickness of the short side surface portion 31b in the conveyance direction) is thinner than the thickness of the long side surface portion 31c in the direction parallel to the short side of the bottom surface portion 31a (in the scanning direction in this embodiment). Is formed.

  Upper portions of the side surface portions 31b and 31c are formed by convex portions (cap lips) 31f. The upper end of the cap lip 31f is the edge of the exhaust cap 31 and surrounds the opening of the recess. The side surface portions 31 b and 31 c are contact portions with which the cap lip 31 f can contact the exhaust surface 24. For example, four fixing portions 31g for fixing to the holder 36 (FIG. 5) are provided on the long side surface portion 31c.

  As shown in FIG. 7, the long side surface portion 31c is composed of a cap lip 31f, an inclined portion 31h, and a base portion 31i. The base portion 31i has a constant thickness in the vertical direction between the inner surface and the outer surface, and has a substantially rectangular cross-sectional shape. A fixing portion 31g is provided on the outer surface of the base portion 31i. The fixing portion 31g protrudes outward from the outer surface of the base portion 31i, and further protrudes downward from the lower surface of the base portion 31i.

  The inclined portion 31h is provided on the base portion 31i and has a substantially trapezoidal cross-sectional shape. The inner surface of the inclined portion 31h extends linearly upward, and the outer surface is inclined inwardly upward. For this reason, the thickness between the inner surface and the outer surface of the inclined portion 31h becomes thinner toward the upper side. Further, the center in the thickness direction of the inclined portion 31h is configured to be closer to the inside as it goes upward.

  The cap lip 31f is provided on the inclined portion 31h. The cross-sectional shape of the cap lip 31f is substantially triangular, and its top is curved in an arc shape. For this reason, the end surface of the cap lip 31f is formed as a curved surface that is curved between the inner surface and the outer surface. The length of the cap lip 31f in the vertical direction is longer than the diameter of the arc. The thickness between the inner surface and the outer surface of the cap lip 31f is thinner than the inclined portion 31h and the base portion 31i. Thereby, the cap lip 31f is more easily bent than the inclined portion 31h and the base portion 31i, and is easily adhered to the exhaust surface 24. The cap lip 31f has an inner surface inclined upward and an outer surface extending linearly upward. For this reason, when the cap lip 31f is brought into contact with the exhaust surface 24, the cap lip 31f is likely to spread outward.

  As shown in FIG. 5, when the exhaust surface 24 of the head 21 is above the exhaust cap 31 in the maintenance area, the bottom surface portion 31 a of the exhaust cap 31 can face the exhaust surface 24. At this time, the side portions 31b and 31c are erected on the exhaust surface 24 side from the bottom portion 31a. The size of the opening of the recess is set so that the cap lip 31f surrounds the entire exhaust hole. Thereby, the exhaust cap 31 covers the exhaust surface 24 so as to include the exhaust hole of the head 21.

  The exhaust cap 31 is accommodated in the holder 36. The holder 36 is provided with an accommodating portion, a suction tube 36a, and a plurality (four in this embodiment) of shafts 36b. The accommodating part is a recess whose upper part opens, and the exhaust cap 31 is accommodated in this recess. The cap lip 31 f of the accommodated exhaust cap 31 protrudes upward from the upper surface of the holder 36. For this reason, when the holder 36 is raised, the cap lip 31 f comes into contact with the exhaust surface 24 before the upper surface of the holder 36. As described above, when the cap lip 31f contacts the exhaust surface 24, the opening of the recess is closed by the exhaust surface 24, and an airtight internal space (closed space) surrounded by the recess and the exhaust surface 24 is formed. The This internal space is adjacent to the exhaust port of the exhaust surface 24.

  The upper end opening of the suction tube 36 a corresponds to the suction hole 31 e of the exhaust cap 31 accommodated in the holder 36. The lower end of the suction tube 36 a is connected to the suction pump 133. Thus, the internal space of the exhaust cap 31 communicates with the suction pump 133 through the suction tube 36a and the suction hole 31e.

  The shaft 36b is a member that is slidably provided in a through hole (insertion hole 31d) provided in the exhaust cap 31 and moves the valve element 34a to open the exhaust passage 26 to the outside. The shaft 36b has a rod shape extending in the vertical direction, and is arranged side by side with an interval in the scanning direction. The shaft 36 b is inserted into the insertion hole 31 d of the exhaust cap 31 accommodated in the holder 36. The shaft 36b is configured to be movable in the vertical direction with respect to the bottom surface portion 31a of the exhaust cap 31 while airtight between the outer peripheral surface of the shaft 36b and the edge of the insertion hole 31d.

  The shaft 36b corresponding to the black ink exhaust flow path 26 can move independently in the vertical direction. On the other hand, the three shafts 36b corresponding to the exhaust flow paths 26 of the three color inks (magenta, cyan, yellow) are connected to each other at their lower ends, and can be moved integrally in the vertical direction. ing. A drive motor (not shown) is connected to these shafts 36b, and the black ink shaft 36b and the color ink shaft 36b are moved up and down independently of each other by the drive motor.

  The pressure adjusting unit 33 is a mechanism that changes the pressure in the internal space of the exhaust cap 31, and includes, for example, a suction pump 133. The suction pump 133 is connected to the suction hole 31e of the exhaust cap 31 by a suction tube 36a, and is provided with a valve (atmospheric release valve) 33a for opening the inside of the recess of the exhaust cap 31 to the atmosphere. When the air release valve 33a is closed, the inside of the recess communicates with the suction pump 133. For this reason, when the suction pump 133 is operated in a state where the exhaust cap 31 is in close contact with the exhaust surface 24, the suction pump 133 passes through the internal space of the exhaust cap 31 mounted on the exhaust surface 24 with the suction tube 36a and the suction hole 31e. The pressure in the internal space is reduced. On the other hand, when the air release valve 33a is opened, the internal space of the exhaust cap 31 is opened to the air, and the pressure in the internal space returns to atmospheric pressure. In this way, the pressure in the internal space of the cap 31 is adjusted.

  The contact / separation portion 32 is a mechanism for bringing the exhaust cap 31 into contact with and separating from the exhaust surface 24. For the contact / separation portion 32, for example, a cam that converts a rotational motion into a lifting motion of the exhaust cap 31 is used. A cam drive motor is attached to the shaft portion of the cam, and the cam rotates around the shaft by the drive of the cam drive motor. The cam 132 has a substantially circular base circle and a cam lobe protruding outward from the shaft portion from the base circle. The cam 132 is disposed so that the circumferential surface thereof is in contact with the lower surface of the holder 36.

  When the portion in contact with the holder 36 moves from the base circle to the cam lobe due to the rotation of the cam 132, the exhaust cap 31 rises together with the holder 36, and the cap lip 31f contacts the exhaust surface 24 of the head 21. As a result, the opening of the recess is closed by the exhaust surface 24, and an airtight closed space surrounded by the recess and the exhaust surface 24 is formed. This closed space is adjacent to the exhaust hole of the exhaust surface 24.

  On the other hand, when the portion in contact with the holder 36 moves from the cam lobe to the base circle due to the rotation of the cam 132, the exhaust cap 31 is lowered in conjunction with the lowering of the holder 36, and the cap lip 31 f is separated from the exhaust surface 24 of the head 21.

  Next, a maintenance operation for removing the fillet 27 formed on the exhaust surface 24 by the cap lip 31f will be described with reference to FIGS. 2, 5, 8 and 9A to 9D. This operation is executed by the control unit 40 controlling the exhaust valve 34, the contact / separation unit 32, the pressure adjustment unit 33, and the like. FIG. 8 is a flowchart illustrating an example of the maintenance operation. FIG. 9A is a diagram schematically showing a state in which the cap lip 31f is in contact with the exhaust surface 24 in the decompression process. FIG. 9B is a diagram illustrating a state where the internal space of the exhaust cap 31 is decompressed in the decompression process. FIG. 9C is a diagram illustrating a state of the communication process. FIG. 9D is a diagram illustrating a state of the discharge process.

  When the exhaust surface 24 is left covered with the exhaust cap 31, the liquid remaining on the exhaust surface 24, which is more easily wetted by the liquid than the exhaust cap 31, is dried, and a fillet 27 is formed on the exhaust surface 24. . The fillet 27 that is the object of this maintenance is a solute solid or gel that remains after evaporation of the liquid solvent. In particular, since the outside of the cap lip 31f is open to the atmosphere, the liquid between the cap lip 31f and the exhaust surface 24 is dried and the fillet 27 is easily formed. In addition, since the cap lip 31f and the exhaust surface 24 are in close contact with each other and the liquid is held therebetween by capillary action, the fillet 27 tends to be high.

  Therefore, if the fillet 27 is sandwiched between the cap lip 31f and the exhaust surface 24 when the exhaust surface 31 is covered with the exhaust cap 31, they cannot be brought into close contact with each other and a gap is opened. In this case, the internal space formed by the recess and the exhaust surface 24 cannot be sufficiently decompressed, and exhaust purge for exhausting gas from the exhaust hole cannot be performed sufficiently.

  The fillet 27 that causes such exhaust failure is removed by wiping the exhaust surface 24 with a wiper member 35 attached with liquid. Therefore, if the liquid purge for discharging the liquid is performed before the exhaust purge, and the exhaust surface 24 is wiped with the wiper member 35 to which the liquid by the liquid purge adheres, the exhaust purge can be performed after the fillet 27 is removed. However, when the exhaust purge is not performed for a long period of time, a large amount of gas is accumulated in the liquid flow path (flexible tube 125b, ink storage chamber 124). For this reason, if all the gas in the liquid cannot be discharged from the liquid flow path by the liquid purge, the gas enters the nozzle 25 from the liquid flow path, and liquid discharge (printing) failure occurs. On the other hand, when the liquid purge is performed so as to remove all the gas in the liquid, it is necessary to discharge a large amount of liquid, and the liquid is wasted. Therefore, it is necessary to perform an exhaust purge before the liquid purge.

  As described above, when the liquid purge is performed after the exhaust purge, the fillet 27 is removed by the wiper member 35 with the liquid attached. Therefore, the exhaust purge is usually caused in the first exhaust purge at the next opportunity. Only one tall fillet 27 is formed on the exhaust surface 24. Therefore, if the relative position between the exhaust surface 24 and the cap does not shift, the exhaust purge can be performed without the fillet 27 being sandwiched between the cap lip 31f and the exhaust surface 24. However, when the head 21 is moved, the relative position may slightly shift, and the fillet 27 may be sandwiched between the cap lip 31f and the exhaust surface 24. In such a situation, it is necessary to perform maintenance so as to suppress the pressure reduction of the internal space due to the recess and the exhaust surface 24 from being reduced by the gap due to the fillet 27.

  This maintenance is performed at a predetermined timing at which the fillet 27 is estimated to be formed. For example, if the elapsed time from the previous maintenance discharge process has reached the first predetermined time and left for a long period of time, it is estimated that the liquid on the nozzle surface 23 has been dried and the fillet 27 has been formed. The For this reason, the control part 40 measures the elapsed time from the last maintenance with a built-in timer, and determines whether this elapsed time has reached the first predetermined time. If the elapsed time has reached the first predetermined time, the maintenance is automatically executed.

  Note that the first predetermined time is set based on the estimated height of the fillet 27. For example, when the height of the fillet 27 is 0.09 mm, the gap between the cap lip 31f and the exhaust surface 24 by the fillet 27 is large, and gas leaks from this gap. A period estimated to be the height of the fillet 27 that causes such a leak is set as a first predetermined time.

  When the power of the liquid ejection device 10 is turned on after the built-in battery is exhausted, the built-in timer is stopped and the elapsed time from the previous maintenance discharge process cannot be determined. In this case, it is estimated that the fillet 27 is formed by leaving the cap lip 31f in contact with the exhaust surface 24 for a long time. For this reason, the control part 40 performs a maintenance, when the elapsed time from the last maintenance cannot be acquired from a built-in timer or the memory which memorize | stores the elapsed time measured by this built-in timer. Thus, the case where “the elapsed time measured by the timer cannot be acquired” includes the case where the timer cannot be measured because the built-in battery has run out. Note that the elapsed time may not be acquired for other reasons. Even in such a case, since the elapsed time from the discharge process of the previous maintenance cannot be determined, the maintenance is executed.

  Specifically, when the maintenance operation is started, first, the head 21 in FIG. 2 is moved to the maintenance area by the carriage 22 and faces the opening of the recess of the exhaust cap 31. Then, the decompression process is executed in the maintenance area (step S1 in FIG. 8). In the decompression process, the exhaust valve 34 is closed and the exhaust cap 31 is in contact with the exhaust surface 24, and the internal space is decompressed by the pressure adjusting unit 33, so that the side surfaces 31b and 31c are placed more inside than before decompression. It is deformed and brought into contact with the exhaust surface 24.

  That is, as shown in FIG. 9A, the exhaust valve 34 is closed. Then, the exhaust cap 31 is raised, and the cap lip 31 f is brought into contact with the exhaust surface 24. The cap lip 31f is thin, the end surface of the cap lip 31f is formed as an arc-shaped curved surface, and the inner surface of the cap lip 31f is inclined outward. For this reason, the cap lip 31 f spreads outward and comes into contact with the exhaust surface 24, and an internal space is formed by the recess and the exhaust surface 24. At this time, the cap lip 31f in contact with the exhaust surface 24 is crushed, and the volume of the internal space due to the recess and the exhaust surface 24 is reduced. Since the static pressure is generated in the internal space by the reduced volume, the cap lip 31f is likely to expand further outward.

  The fillet 27 is formed between or on the outer side of the cap lip 31f spreading outward and the exhaust surface 24. For this reason, the size of the annular fillet 27 formed on the exhaust surface 24 is larger than the size of the undeformed annular cap lip 31f.

  Then, as shown in FIG. 9B, the internal space is suctioned by the suction pump 133 to reduce the pressure. Here, by rotating the suction pump 133 faster than the speed in the discharge process described later, the pressure in the internal space is lowered to a pressure lower than the pressure in the internal space in the discharge process, for example, −70 kPa. Here, even if the fillet 27 is sandwiched between the cap lip 31f and the exhaust surface 24, the suction space is sucked by the suction pump 133 by high-speed rotation, so that the internal space can be decompressed. As a result, the cap lip 31f is deformed and inclined inward. At this time, since the end surface of the cap lip 31f is formed in an arcuate curved surface, the cap lip 31f can be deformed while maintaining line contact with the exhaust surface 24. In this way, the cap lip 31 f inclined inward contacts the exhaust surface 24 inside the fillet 27. When the cap lip 31f is inclined inward, the inclined portions 31h and / or the base portion 31i of the side surface portions 31b and 31c may be deformed inward.

  After this decompression process, a communication process is executed (step S2 in FIG. 8). In the communication process, the exhaust valve 34 is closed, and the internal space and the external space are communicated by the pressure adjusting unit 33 while the exhaust cap 31 is deformed and brought into contact with the exhaust surface 24 inward. .

  That is, as shown in FIG. 9C, the exhaust cap 31 is not lowered while the exhaust valve 34 is closed. Thereby, since the decompressed internal space is maintained, the state where the cap lip 31f that has fallen inward is in contact with the exhaust surface 24 is maintained. When the atmosphere release valve 33a is opened, the internal space covered with the recess and the exhaust surface 24 communicates with the outside space (external space) via the suction tube 36a and the atmosphere release valve 33a to be released to the atmosphere. Is done. As a result, gas flows into the internal space, and the pressure in the reduced internal space returns to atmospheric pressure or a pressure close thereto. For this reason, the cap lip 31f that has fallen inward is slightly deformed outward. However, since the cap lip 31f is in contact with the exhaust surface 24, the cap lip 31f does not return to its original shape due to the frictional force during this time, and the state in which the cap lip 31f is in contact with the exhaust surface 24 inside the fillet 27 is Maintained.

  After this communication process, a discharge process is executed (step S3 in FIG. 8). In the exhaust process, the exhaust valve 34 is opened while the exhaust cap 31 is in contact with the exhaust surface 24, the internal space is decompressed again, and the gas is exhausted from the exhaust passage 26.

  That is, as shown in FIG. 9D, the cap lip 31 f that has fallen inward is kept in contact with the exhaust surface 24 without lowering the exhaust cap 31. And the exhaust valve 34 is opened, and the exhaust flow path 26 and internal space are connected. Further, when the air release valve 33a is closed and the internal space is sucked by the suction pump 133, the pressure in the internal space is reduced again. At this time, the suction pump 133 is rotated so that a predetermined pressure in the internal space for discharging the gas from the exhaust passage 26, for example, −7 kPa. As a result, the gas in the exhaust passage 26 is sucked and discharged through the internal space. Then, the wiper member 35 (FIG. 2) is brought into contact with the nozzle surface 23 and the exhaust surface 24 in this order and moved relatively to wipe off the liquid and fillet 27 adhering to the nozzle surface 23 and the exhaust surface 24. The predetermined pressure in the internal space is appropriately set depending on the size of the exhaust passage 26, the viscosity of the liquid, and the like.

  After such an exhaust purge maintenance for exhausting gas from the exhaust passage 26, a liquid purge for discharging liquid from the nozzle 25 may be performed. In the liquid purge, a cap (nozzle cap 37, FIG. 1) that can cover the nozzle surface 23 is used.

  The nozzle cap 37 covers the nozzle surface 23 including the nozzle hole with the exhaust cap 31, and the suction pump 133 sucks the inside of the recess of the nozzle cap 37, whereby the liquid is discharged from the nozzle hole. And the inside of a recessed part is open | released to air | atmosphere, the inside of a recessed part is attracted | sucked, and the liquid in a recessed part is discharged | emitted. Then, the wiper member 35 (FIG. 2) is moved in contact with the nozzle surface 23 and the exhaust surface 24 in this order, and the liquid and fillet 27 adhering to the nozzle surface 23 and the exhaust surface 24 are wiped off.

  According to the above-described embodiment, in the decompression process, the internal space formed by the exhaust cap 31 and the exhaust surface 24 is decompressed, and the cap lips 31f of the side surface portions 31b and 31c are deformed inward than before the decompression, thereby exhausting the exhaust surface 24. It is made to contact. Thereby, the cap lip 31 f of the exhaust cap 31 can be brought into contact with the exhaust surface 24 inside the fillet 27. Therefore, it is possible to perform the discharge process while suppressing the leakage caused by the fillet 27 between the cap lip 31f and the exhaust surface 24.

  The pressure in the internal space in the decompression process is set lower than the pressure in the internal space in the discharge process. For this reason, even if a leak occurs between the cap lip 31f and the exhaust surface 24 due to the fillet 27, the cap lip 31f can be deformed inward and brought into contact with the exhaust surface 24.

  In the communication process, the internal space and the external space are communicated with the cap lip 31f deformed inward in contact with the exhaust surface 24. As a result, the pressure in the internal space is relaxed and, for example, this pressure returns to atmospheric pressure or a pressure close thereto. Therefore, the internal space can be accurately depressurized by the discharge process after the communication process with reference to the returned pressure. That is, if the discharge process is performed after the decompression process without performing the communication process, the pressure in the internal space is too low than the predetermined pressure, leading to waste of liquid and a liquid discharge defect (printing defect) of the liquid discharge device 10. On the other hand, if the pressure in the internal space is too higher than the predetermined pressure, the gas cannot be sufficiently discharged from the exhaust flow path 26, and the gas remains in the exhaust flow path 26, causing a liquid discharge failure of the liquid discharge apparatus 10.

  Further, in the discharge process, the internal space is decompressed while the cap lip 31f is in contact with the exhaust surface 24. For this reason, leakage by the fillet 27 between the cap lip 31f and the exhaust surface 24 is prevented, and the internal space can be accurately decompressed.

  Further, since the exhaust surface 24 is more easily wetted by the liquid than the cap, the liquid remains on the exhaust surface 24 and is dried, and the fillet 27 is formed on the exhaust surface 24. Thus, the fillet 27 formed on the exhaust surface 24 can be removed by the wiper member 35.

  Further, the short side surface portion 31b of the cap is shorter than the long side surface portion 31c and is difficult to deform. For this reason, if the internal space is depressurized by making the thickness of the short side surface portion 31b the same as that of the long side surface portion 31c, the long side surface portion 31c is inclined inward while the short side The side surface part 31b is easy to spread outward. On the other hand, the thickness of the short side surface portion 31b is made thinner than that of the long side surface portion 31c, and the rigidity of the short side surface portion 31b is made lower than that of the long side surface portion 31c. For this reason, the short side surface portion 31b can be inclined inwardly in the same manner as the long side surface portion 31c, and the entire cap lip 31f can be brought into contact with the exhaust surface 24 inside the fillet 27.

  Further, since the cap lip 31f is thin, the cap lip 31f is easily deformed inward. Furthermore, since the end surface of the cap lip 31f is formed as a curved surface, the cap lip 31f can be deformed while maintaining the state where the cap lip 31f is in line contact with the exhaust surface 24. Further, since the inner surface of the cap lip 31f is inclined outwardly upward, the cap lip 31f can be expanded outward and brought into contact with the exhaust surface 24. As a result, the size of the annular fillet 27 on the exhaust surface 24 becomes larger than the size of the annular cap lip 31f that is not deformed, so that the cap lip 31f is deformed inward to contact the exhaust surface 24 inside the fillet 27. Easy to do.

  Further, in order to prevent the fillet 27 from leaking in the cap 31, it is not necessary to separately prepare a pump other than the suction pump 133. Therefore, an increase in cost can be suppressed.

(Embodiment 2)
In the liquid ejection device 10 according to the first embodiment, the maintenance including the decompression process, the communication process, and the discharge process is performed at a predetermined timing at which the fillet 27 is estimated to be formed. On the other hand, it is not necessary to perform maintenance including pressure processing, communication processing, and discharge processing at all of the predetermined timings.

  For example, even if it is estimated that the fillet 27 is formed, if the fillet 27 is low, the gap due to the fillet 27 between the cap lip 31f and the exhaust surface 24 is small. For this reason, gas can be discharged | emitted from the exhaust flow path 26 only by discharge processing. Therefore, for example, when the elapsed time from the previous maintenance reaches a second predetermined time shorter than the first predetermined time, the fillet 27 is formed, but the height is estimated to be low. For this reason, the control part 40 measures the elapsed time from the last maintenance with a built-in timer, and determines whether this elapsed time is less than 1st predetermined time and 2nd predetermined time or more. If the elapsed time is less than the first predetermined time and longer than the second predetermined time, only the discharge process is executed.

  Note that the second predetermined time is set based on the estimated height of the fillet 27. For example, when the height of the fillet 27 is 0.045 mm, there is no or little gap between the cap lip 31f and the exhaust surface 24 due to the fillet 27, so that leakage does not occur or hardly occurs. A period estimated to be the height of the fillet 27 in which such a leak does not occur or hardly occurs is set as the second predetermined time.

(Embodiment 3)
In the liquid ejection apparatus 10 according to the first embodiment, the maintenance for exhausting the gas from the exhaust passage 26 is performed using the exhaust cap 31 that covers the exhaust surface 24. In contrast, in the liquid ejection apparatus 10 according to the third embodiment, maintenance is performed to discharge the liquid from the nozzle 25 using a cap (nozzle cap) 37 that can cover the nozzle surface 23 shown in FIG. May be. FIG. 10 is a block diagram illustrating a functional configuration of the liquid ejection apparatus 10 according to the third embodiment.

  In this case, the area of the bottom surface of the nozzle cap 37 is larger than the bottom surface 31 a of the exhaust cap 31 in order to cover the nozzle surface 23 larger than the exhaust surface 24. However, since the nozzle cap 37 has the same shape as the exhaust cap 31, the description of the nozzle cap 37 is omitted.

  Further, when the shaft of the nozzle cap 37 is not provided with a shaft, the bottom surface of the nozzle cap 37 is not provided with an insertion hole into which the shaft is inserted. However, a suction hole is provided in the bottom surface of the nozzle cap 37, and the pressure adjusting part 33 is connected to the suction hole. Note that a pressure adjusting unit different from the pressure adjusting unit 33 may be connected to the suction hole of the nozzle cap 37. Further, although the nozzle cap 37 is raised and lowered by the contact / separation part 32, the nozzle cap 37 may be raised and lowered by a contact / separation part different from the contact / separation part 32.

  Further, a valve (nozzle valve) 38 for opening and closing the liquid flow path (flexible tube 125b, ink storage chamber 124 in FIG. 1) is provided in the liquid flow path. The opening and closing of the nozzle valve 38 is controlled by the control unit 40.

  In the maintenance, after the exhaust purge for exhausting the gas from the exhaust flow path 26, a liquid purge pressure reduction process is executed (step S1 in FIG. 8). In this decompression process, the nozzle valve 38 is closed, the nozzle cap 37 is raised by the contact / separation portion 32, and the cap lip of the nozzle cap 37 is brought into contact with the nozzle surface 23. In this state, the internal space of the nozzle cap 37 is depressurized by the pressure adjusting unit 33, and the side surface of the nozzle cap 37 is deformed inward than before the depressurization.

  After the decompression process, a communication process is executed (step S2 in FIG. 8). Here, the internal space and the external space of the nozzle cap 37 are made to communicate with each other by the pressure adjusting unit 33 while the nozzle valve 38 is closed. Thus, the internal space and the external space are communicated with the cap lip in contact with the nozzle surface 23. Here, the cap lip that has fallen inward is slightly deformed outward, but the cap lip does not return to its original shape, and the state of contacting the nozzle surface 23 inside the fillet 27 is maintained.

  After the communication process, the discharge process is executed (step S3 in FIG. 8). Here, while the nozzle cap 37 is in contact with the nozzle surface 23, the nozzle valve 38 is opened, and the internal space of the nozzle cap 37 is again decompressed by the pressure adjusting unit 33. Thereby, the liquid is discharged from the nozzle 25.

(Other)
In all the embodiments described above, the atmosphere release valve 33a provided in the suction pump 133 is opened to allow the internal space and the external space to communicate with each other. On the other hand, the method of communicating this internal space is not limited to this. For example, the air release valve 33 a may be provided in the exhaust cap 31 instead of the suction pump 133.

  In all the embodiments described above, the caps 31 and 37 are moved by the contact / separation portion 32 so that the cap lips of the caps 31 and 37 abut against and separate from the head surfaces 23 and 24. On the other hand, as long as the cap lip of the caps 31 and 37 is in contact with and separated from the head surfaces 23 and 24, the contact / separation portion 32 is not limited thereto. For example, the cap lips of the caps 31 and 37 may be brought into contact with and separated from the head surfaces 23 and 24 by the contact / separation part 32 that moves the head 21. Alternatively, the cap lips of the caps 31 and 37 may be brought into contact with and separated from the head surfaces 23 and 24 by the contact / separation portions 32 that move the caps 31 and 37 and the head 21, respectively.

  In all the embodiments described above, the inner surface of the cap lip 31f is inclined outward and upward so that the cap lip 31f extends outward and comes into contact with the exhaust surface 24. However, the shape of the cap lip 31f is not limited to this, and the inner surface of the cap lip 31f may not be inclined or may be inclined inwardly upward. As a result, when the cap lip 31f contacts the exhaust surface 24, the cap lip 31f does not expand or easily expands inward.

  Note that all the above embodiments may be combined with each other as long as they do not exclude each other. From the above description, many modifications and other embodiments of the present invention are obvious to those skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  The liquid ejection apparatus of the present invention is useful as a liquid ejection apparatus that can suppress problems caused by fillets corresponding to the edges of the cap.

10: Liquid ejection device 20: Head 22: Nozzle surface (head surface)
23: Exhaust surface (head surface)
24: Nozzle (flow path)
25: Exhaust flow path (flow path)
34: Exhaust valve (valve)
31: Exhaust cap (cap)
32: Contacting / separating part 33: Suction pump (pressure adjusting part)
37: Nozzle cap (cap)
38: Nozzle valve (valve)
40: Control unit 124: Ink storage chamber (gas storage chamber)

Claims (7)

A head having a head surface formed with an opening located at a downstream end of a flow path through which a liquid or a gas in the liquid flows;
A valve for opening and closing the flow path;
A cap having a bottom surface portion that can face the head surface, and a contact portion that stands from the bottom surface to the head side, the contact portion contacting the head surface and adjacent to the opening. A cap capable of covering the head surface so as to form an internal space;
A contact / separation part for moving at least one of the head and the cap to contact and separate the cap from the head surface;
A pressure adjusting unit that changes the pressure of the internal space;
A control unit for controlling the valve, the contacting / separating unit and the pressure adjusting unit,
The controller is
In a state where the valve is closed and the cap is in contact with the head surface, the internal space is depressurized by the pressure adjusting unit, and the abutting portion is deformed inward than before the depressurization, so that the head surface Pressure reduction treatment to contact with,
After the depressurization process, the internal space and the external space are communicated by the pressure adjusting unit while the valve is closed and the cap is deformed and brought into contact with the head surface. Communication processing,
After the communication process, with the cap held in contact with the head surface, the valve is opened, the internal space is decompressed again, and the liquid or the gas is discharged from the flow path. The liquid ejecting apparatus is configured to perform the operation. The controller is
The liquid ejecting apparatus according to claim 1, wherein the pressure adjusting unit is controlled so that a pressure in the internal space in the decompression process is lower than a pressure in the internal space in the discharge process. The bottom surface portion of the cap has a rectangular shape, and the contact portion includes a short side contact portion standing on the head side from a short side of the bottom surface portion, and a long side of the bottom surface portion. Has a long side abutting portion standing on the head side,
The thickness of the short side contact portion in a direction parallel to the long side of the bottom surface portion is thinner than the thickness of the long side contact portion in a direction parallel to the short side of the bottom surface portion. The liquid discharge apparatus according to 1. A gas storage chamber for storing the gas in the flow path;
An exhaust passage communicating with the gas storage chamber, and
The head surface is an exhaust surface having an opening connected to the exhaust flow path and exhausting the gas,
The cap is an exhaust cap capable of covering the exhaust surface;
The valve is provided in the exhaust passage, and is provided in a slidable manner in a valve body that is always closed and movable in the exhaust passage, and in a through hole provided in the exhaust cap, and moves the valve body. And an exhaust valve that opens and closes the exhaust flow path.
The liquid ejection apparatus according to any one of claims 1 to 3. A timer for measuring an elapsed time from the previous discharging process executed;
The controller is
5. The apparatus according to claim 1, wherein when the elapsed time measured by the timer reaches a first predetermined time, the decompression process, the communication process, and the discharge process are executed. The liquid discharge apparatus as described. The controller is
When the elapsed time measured by the timer reaches a second predetermined time shorter than the first predetermined time, the discharge process is executed without executing the decompression process and the communication process. The liquid ejection device according to claim 5. A timer for measuring an elapsed time from the previous discharging process executed, and
The controller is
The liquid ejecting apparatus according to any one of claims 1 to 6, wherein when the elapsed time measured by the timer cannot be acquired, the pressure reduction process, the communication process, and the discharge process are executed. .

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