JP4841344B2 - Head maintenance / recovery device, liquid ejection device, and image forming device - Google Patents

Description

  The present invention relates to a head maintenance / recovery device, a liquid ejection device, and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, or a multifunction machine of these, for example, a liquid (e.g., a liquid ejecting apparatus) including a recording head composed of a liquid ejecting head for ejecting liquid droplets of a recording liquid (liquid) is used. Hereinafter, although it is also referred to as “paper”, the material is not limited, and a recording medium as a liquid (hereinafter, referred to as “recording medium”, “recording medium”, “transfer material”, “recording paper” and the like is also used synonymously). Some of them perform image formation (recording, printing, printing, and printing are also used synonymously) by attaching the ink to the paper.

  The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The term “not only” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium. Further, the liquid is not limited to the recording liquid and ink, and is not particularly limited as long as it is a liquid capable of forming an image. Further, the liquid ejection apparatus means an apparatus that ejects liquid from a liquid ejection head, and is not limited to an apparatus that forms an image.

  Thus, in a liquid ejection device that ejects liquid droplets from a liquid ejection head and an image forming apparatus including the liquid ejection device, the nozzle is formed by adhering foreign matter such as thickened or dried ink, dust, or dust to the nozzle outer surface of the head. In order to prevent the normal ejection from occurring due to the occurrence of clogging in the nozzle or the occurrence of air damper phenomenon due to the generation of bubbles inside the nozzle, etc., to maintain and recover the reliability of the head A head maintenance and recovery mechanism (device) is indispensable.

  This head maintenance and recovery mechanism includes a cap (cap member) that seals the nozzle surface (surface on which droplets are discharged) of the head. In addition, an operation of sucking ink filled in the head from the nozzle by a suction means such as a suction pump communicating with the cap (head suction or nozzle suction), or a wiper blade using an elastic member such as rubber A wiping operation on the head surface, an idle ejection operation (or also referred to as a preliminary ejection operation) for ejecting ink so as not to contribute to image formation, and ejecting thickened ink or mixed color ink in the nozzle hole and in the vicinity of the entrance. In combination, an operation of removing bubbles, thickened ink, attached dust, and the like in the liquid chamber and maintaining a state in which stable droplet discharge can be performed is performed.

As a conventional cap member and head maintenance / recovery device, as described in Patent Document 1, at the bottom of the cap member, at least two inclined surfaces inclined toward the discharge port are provided, and the horizontal surface of the inclined surface is provided. And the sum of the contact angles between the member forming the inclined surface and the recording liquid is 70 ° or more.
JP 2005-271458 A

In addition, as described in Patent Document 2, a cap member that forms a sealed space when contacted with the nozzle formation surface of the liquid jet head, and a fluid in the sealed space are discharged to provide a sealed space. A negative pressure generating means for generating a negative pressure therein, and a filter member arranged so that at least a part of the negative pressure generating means is located inside the cap member, and downstream of the filter member in the fluid flow direction during suction In addition, there is a common negative pressure chamber for applying a substantially uniform negative pressure to substantially the entire filter member, and the negative pressure generating means discharges the fluid inside the common negative pressure chamber.
Japanese Patent Laid-Open No. 2003-341077

Further, as described in Patent Document 3, a cap member that covers a plurality of nozzle rows each having a plurality of nozzle openings formed in the nozzle plate, and an internal space (sealed space) surrounded by the cap member and the nozzle plate And a suction pump for generating negative pressure, and the cap member is formed with a groove as a recess facing one of the plurality of nozzle rows in a state where the cap member covers the plurality of nozzle rows. There is something that has been configured.
JP 2005-262822 A

  By the way, a suction pump that communicates by forming a sealed space by capping the nozzle surface (the surface on which the nozzle is formed) of the head with a cap member on which the liquid absorbing member is arranged to form a sealed space. When the vacuum is applied to the sealed space and suction is performed from the nozzle of the head, in order to remove the waste liquid (recording liquid) absorbed by the liquid absorbing member, a uniform negative pressure is applied to the liquid absorbing member. There is a need.

  However, a relatively large negative pressure is generated in the vicinity of the discharge port to which the suction pump is connected, but the negative pressure is relatively small in a place away from the discharge port, and a uniform negative pressure (with respect to the liquid absorbing member) It is difficult to apply a suction force), and the recording liquid that becomes a waste liquid remains in the liquid absorbing member.

  As described above, the recording liquid remaining in the liquid absorbing member gradually increases when the liquid discharge head discharge recovery process is repeated, and the liquid is evaporated to become high viscosity, thereby improving the liquid absorbing performance of the liquid absorbing member. It will deteriorate rapidly. In recent years, from the viewpoint of improving image quality, pigment-based recording liquids are often used, and the tendency to increase the viscosity is more remarkable than that of dye-based recording liquids.

  In addition, when a highly viscous recording liquid such as a pigment-based recording liquid is used, when the head is capped by the cap member while the residual recording liquid of the liquid absorbing member is dry, the recording liquid in the dry state is reversed. Moisture is removed from the recording liquid in the nozzle, and the recording liquid in the nozzle of the recording head is deprived of moisture, causing a sudden increase in viscosity, resulting in thickening of the recording liquid in the nozzle and clogging. , May cause ejection failure.

  Therefore, the liquid absorbing member is effective in achieving a moisturizing effect when the cap surface of the head is capped with a cap member, but it can be surely sucked and discharged so that no recording liquid remains in the liquid absorbing member. There must be.

  The cap member described in Patent Document 2 described above forms a common negative pressure chamber that generates a uniform negative pressure over the entire surface of the liquid absorbing member. This is a space formed on the back side (the side opposite to the cap side), and the problem that uniform suction cannot be performed on the back side of the liquid absorbing member is not solved at all even if suction is performed from the discharge port.

  Further, the cap member described in Patent Document 3 is also merely a groove formed as a recess facing one of the plurality of nozzle rows, and is a place far from the discharge port (suction port) in the liquid absorbing member. The above-mentioned problem that the recording liquid remains due to weakening of the suction to the liquid has not been solved at all.

  The present invention has been made in view of the above problems, and a head maintenance and recovery device capable of reducing the amount of residual liquid remaining in the liquid absorbing member in the cap member and always maintaining stable ejection recovery performance. It is an object of the present invention to provide a liquid ejection apparatus and an image forming apparatus including the above.

In order to solve the above problem, a head maintenance / recovery device according to the present invention includes:
A cap member for capping the ejection surface for ejecting droplets of the liquid ejection head;
A liquid absorbing member provided in the cap member;
A suction means connected to a discharge port formed at the bottom of the cap member,
The cap member has a quadrangular shape when viewed in a plane, and the discharge port is provided at the center of the bottom.
A convex portion including a plurality of island-shaped convex portions that support the liquid absorbing member is formed on the bottom portion of the cap member, and a space formed between the convex portion and the liquid absorbing member is the drain. It becomes a passage leading to the exit,
The passage, in plan view, Ri shape der that branches radially towards the said discharge port in the outer peripheral direction of the rectangular four corners,
The plurality of island-shaped convex portions are formed between the plurality of branched passages, and the passage is formed so as to surround the plurality of island-shaped convex portions. did.

  In these head maintenance and recovery devices, the area of the support surface of the convex portion of the cap member is preferably 30% or more of the area of the liquid absorbing member.

Further, the liquid discharge head can be configured to be a liquid discharge head having a plurality of nozzle rows that discharge liquids of different colors or a plurality of liquid discharge heads that discharge liquids of different colors.

  The liquid ejection apparatus according to the present invention and the image forming apparatus according to the present invention are configured to include the head maintenance / recovery apparatus according to the present invention.

  In the image forming apparatus according to the present invention, a recording liquid containing at least water, a colorant, and a wetting agent and having a viscosity at 25 ° C. of 5 to 30 mPa · s can be used.

According to the head maintenance / recovery device of the present invention, a cap member for capping a discharge surface for discharging droplets of a liquid discharge head, a liquid absorbing member provided in the cap member, and a bottom portion of the cap member are formed. A suction member connected to the discharge port, and the cap member has a quadrangular shape when viewed in plan, and a discharge port is provided at the center of the bottom, and a liquid absorbing member is provided at the bottom of the cap member. A convex portion including a plurality of island-shaped convex portions to be supported is formed, and a space formed between the convex portions and the liquid absorbing member serves as a passage leading to the discharge port. Ri shape der that branches radially toward the outer periphery of the rectangular four corners from the outlet, the convex portion of the plurality of islands between the plurality of passages were branching is formed, the periphery of the convex portion of the plurality of islands configuration passage is formed so as to surround the Therefore, by generating a negative pressure in the passage facing the back side of the liquid absorbing member by the operation of the suction means, a substantially uniform negative pressure can be applied to the liquid absorbing member, and the residual remaining in the liquid absorbing member It is possible to reduce the amount of liquid and always maintain stable discharge recovery performance.

  According to the liquid ejection device according to the present invention and the image forming apparatus according to the present invention, since the head maintenance / recovery device according to the present invention is provided, stable droplet ejection can be performed. According to the image forming apparatus of the present invention, since the head maintenance / recovery device of the present invention is provided, stable droplet ejection can be performed, and stable image formation can be performed.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus according to the present invention that includes the liquid ejection apparatus according to the present invention will be described. FIG. 1 is a perspective explanatory view of the image forming apparatus as viewed from the front side.
The image forming apparatus includes an apparatus main body 1, a paper feed tray 2 for loading paper loaded in the apparatus main body 1, and a sheet on which an image is recorded (formed) by being detachably mounted on the apparatus main body 1. A paper discharge tray 3 for stocking is provided. Further, a cartridge loading for loading an ink cartridge that protrudes from the front surface to the front side of the apparatus main body 1 and is lower than the upper surface is provided at one end side of the front surface of the apparatus main body 1 (side of the paper supply / discharge tray section) The cartridge loading unit 4 has an operation / display unit 5 provided with operation buttons and a display.

  The cartridge loading unit 4 includes a plurality of recording liquid cartridges that contain recording liquids (inks) of different colors, for example, black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink. Ink cartridges 10k, 10c, 10m, and 10y (referred to as “ink cartridge 10” when colors are not distinguished) are inserted from the front side to the rear side of the apparatus main body 1 and can be loaded. A front cover (cartridge cover) 6 that is opened when the ink cartridge 10 is attached or detached is provided on the front side of the unit 4 so as to be openable and closable.

Next, the mechanism of the image forming apparatus will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram for explaining the overall configuration of the mechanism unit, and FIG. 3 is a plan view for explaining a main part of the mechanism unit.
A carriage 33 is slidably held in the main scanning direction by a main guide rod 31 and a sub guide rod 32 that are horizontally mounted on the left and right main side plates 21A and 21B constituting the frame 20, and a timing belt is held by a main scanning motor (not shown). 3 is moved and scanned in the direction indicated by the arrow in FIG.

  The carriage 33 is provided with a plurality of recording heads 34 each including a plurality of liquid ejection heads having a plurality of nozzle rows for ejecting droplets of respective colors of yellow (Y), cyan (C), magenta (M), and black (K). The nozzles (ejection ports) are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

  As shown in FIG. 4, in the recording head 34, a plurality of nozzles 34n that discharge yellow (Y), cyan (C), magenta (M), and black (K) droplets are arranged on a nozzle surface 34a. The nozzle rows NY, NC, NM, NK are provided.

  As an inkjet head constituting the recording head 34, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. It is possible to use a shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet.

  The carriage 33 is mounted with a head tank 35 of each color (which may be integrated) for supplying ink of each color to each recording head 34. As described above, each color head tank 35 is supplementarily supplied with ink of each color from the ink cartridge 10 of each color mounted in the cartridge loading unit 4 via the supply tube 36 having flexibility of each color. The cartridge loading 4 is provided with a supply pump unit 24 which is a liquid feeding means for feeding ink in the ink cartridge 10. The supply tube 36 is held on the front stay 29 by a holding member 37 in the middle.

  On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (pressure plate) 41 of the paper feeding tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 one by one from the paper stacking unit 41. A separation pad 44 made of a material having a large friction coefficient is provided facing the paper roller 43) and the paper feed roller 43, and the separation pad 44 is urged toward the paper feed roller 43 side.

  In order to feed the paper 42 fed from the paper feeding unit to the lower side of the recording head 34, a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressure roller. And a holding belt 48 which is a conveying means for electrostatically attracting the fed paper 42 and conveying it at a position facing the recording head 34.

  The transport belt 51 is an endless belt, and is configured to wrap around the transport roller 52 and the tension roller 53 and circulate in the belt transport direction (sub-scanning direction). Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided. The charging roller 56 is disposed so as to come into contact with the surface layer of the transport belt 51 and to rotate following the rotation of the transport belt 51. Further, a guide member 57 serving as a platen portion is disposed on the back side of the conveyance belt 51 so as to correspond to a printing area by the recording head 34.

  The transport belt 51 rotates in the belt transport direction of FIG. 3 when the transport roller 52 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61 for separating the paper 42 from the conveying belt 51, a paper discharge roller 62, and a paper discharge roller 63 are provided. The paper discharge tray 3 is provided below the paper discharge roller 62.

  A duplex unit 71 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the conveyance belt 51, reverses it, and feeds it again between the counter roller 46 and the conveyance belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

  Further, as shown in FIG. 3, a maintenance / recovery mechanism 81 including a recovery means for maintaining and recovering the state of the nozzles of the recording head 34 is arranged in the non-printing area on one side of the carriage 33 in the scanning direction. Yes.

  The maintenance / recovery mechanism 81 includes a cap member 82 for collectively capping the nozzles 31a of the recording head 31, a wiper blade 83 which is a blade member for wiping the nozzle surface, and a thickened recording liquid. An empty discharge receptacle 84 for receiving droplets when performing empty discharge for discharging droplets that do not contribute to recording in order to be discharged is provided.

  Then, the waste liquid of the recording liquid generated by the maintenance / recovery operation by the maintenance / recovery mechanism 81, the ink discharged to the cap 82, the ink attached to the wiper blade 83 and removed by the wiper cleaner 85, and the idle ejection to the idle ejection receiver 94. The discharged ink is discharged and stored in a waste liquid tank (not shown).

  Further, as shown in FIG. 3, in the non-printing area on the other side in the scanning direction of the carriage 33, idle discharge is performed to discharge liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An empty discharge receiver 88 for receiving the liquid droplets at the time is disposed, and the empty discharge receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 34.

  In the ink jet recording apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feeding tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide 45, and the transport belt 51 and the counter roller 46, and the leading end is guided by the conveying guide 37 and pressed against the conveying belt 51 by the tip pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a charging voltage pattern in which a positive output and a negative output are alternately repeated from the AC bias supply unit of the control unit (not shown) to the charging roller 56, that is, an alternating voltage is applied and the conveying belt 51 alternates. That is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction which is the circumferential direction. When the paper 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the paper 42 is attracted to the conveyance belt 51, and the paper 42 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 51.

  Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.

  During printing (recording) standby, the carriage 33 is moved to the maintenance / recovery mechanism 81 side, and the ejection surface 34a of the recording head 34 is capped by the cap member 82, and the recording liquid is dried by keeping the nozzle in a wet state. Prevents ejection failure due to In addition, the recording liquid is sucked from the nozzle by a suction pump (not shown) in the state where the ejection surface 34a of the recording head 34 is capped by the cap member 82 (referred to as “nozzle suction” or “head suction”) to increase the viscosity. A recovery operation is performed to discharge the recording liquid and bubbles. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. As a result, the stable ejection performance of the recording head 34 is maintained.

  A head maintenance / recovery mechanism (apparatus) and a first embodiment according to the present invention in this image forming apparatus will be described with reference to FIGS. 5 is a partially perspective view illustrating the structure of the recovery mechanism, FIG. 6 is a cross-sectional view taken along the line AA of the cap member of FIG. 5, and FIG. 7 is a plan view of the cap member. .

  The cap member 82 includes a contact member 101 made of an elastic member such as rubber or elastomer that forms a contact portion (cap nip portion) 101a that contacts the discharge surface (nozzle surface) 34a of the recording head 34, and a contact portion 101a. Is provided with a recess forming member 102 for forming a recess for forming a sealed space together with the discharge surface 34a in contact with the discharge surface 34a, and a liquid absorbing member 103 formed of a porous body or the like.

  A discharge port (suction hole) 106 is formed in the recess forming member 102 of the cap member 82, and a suction pump 108 as a suction means is connected to the discharge port 106 through a tube 107A. The suction pump 108 discharges the waste liquid to the waste liquid storage container (waste liquid tank) 109 via the waste liquid tube 107B.

  Then, an island-shaped convex portion 111 that supports the lower surface of the liquid absorbing member 103 and a convex portion 112 that is partly integrated with the outer peripheral portion of the concave portion of the concave portion forming member 102 are formed at the bottom of the concave portion forming member 102 of the cap member 82. In addition, as shown in FIG. 7, the portion excluding these convex portions 111 and 112 has a planar shape and branches from the discharge port 106 toward the outer peripheral direction (indicated by phantom lines in the figure). ing.

  The passage 113 is a space formed by the wall surfaces of the convex portions 111 and 112, the bottom surface of the concave portion forming member 102, and the lower surface (back surface) of the liquid absorbing member 103. In other words, the bottom of the recess forming member 102 of the cap member 82 is formed with a recess 113A having a planar shape and branching from the discharge port 106 toward the outer peripheral direction.

  Further, the recess forming member 102 of the cap member 82 is provided with four bosses 115 that substantially determine the position of the liquid absorbing member 103 supported by the upper surfaces (supporting surfaces) of the protruding portions 111 and 112. Is formed with a through hole 103a into which the boss 115 is fitted. Further, when the nozzle surface 34a of the recording head 34 is capped with the cap member 82, a sealed space 116 which is a single space is formed.

  In a state where the ejection surface 34a of the recording head 34 is capped by the cap member 82 configured in this manner, the liquid absorbing member 103 that plays a role of preventing ejection failure due to ink drying by keeping the nozzle 34n in a wet state is the convex portion 111. , 112 are securely held.

  Further, in order to maintain the stable ejection performance of the recording head 34, the suction pump 108 is operated with the cap member 82 capping the ejection surface 34a of the recording head 34 (the cap nip portion 101a is in contact). By operating and suctioning from the discharge port 106, the air in the passage 113 and the sealed space 115 in the cap member 82 is sucked in the direction of the waste liquid tank 109, and ink is sucked from the nozzle 34n of the recording head 34 to be liquid. It is discharged toward the absorbing member 103 and absorbed.

  At this time, since the passage 113 has a planar shape and branches from the discharge port 106 toward the outer periphery as described above, the passage 113 (concave portion 113a) can be distributed over the entire back surface of the liquid absorbing member 103. When suction is performed from the discharge port 106, the pressure inside the passage 113 becomes substantially uniform throughout. Accordingly, the negative pressure acting on the back surface of the liquid absorbing member 103 corresponding to the passage 113 is substantially uniform throughout.

  Here, the width of the support surface of the convex portion 111 that supports the liquid absorbing member 103 will be described. If the recess 113a spreads over the entire surface of the liquid absorbing member 103, the pressure acting on the liquid absorbing member 103 becomes more uniform, but if it becomes difficult to support the liquid absorbing member 103 from below, the cap member 82 is used. The liquid absorbing member 103 cannot be stably disposed inside.

  Therefore, in order to perform uniform suction, it is preferable that the concave portion 113a is wide and the convex portion 111 is small. On the other hand, considering the assembling property, the larger the support surface area of the convex portion 111 that supports the liquid absorbing member 103 from below, the more stable placement and fixing is possible, so the concave portion 113a and the convex portion 111 have a trade-off relationship. It is in.

  Therefore, the ratio of the area of the support surface of the convex portion 111 to the area of the liquid absorbing member 103 was changed to evaluate whether the liquid absorbing member 103 can be fixed. A cap member 82 in which the ratio (area ratio) of the support surface of the convex portion 111 to the area of the back surface of the liquid absorption member 103 is changed is used to determine whether the liquid absorption member 103 can be fixed. Judgment was made. The result is shown in FIG.

  In FIG. 8, “absorber fixability” is an evaluation item as to whether or not the liquid absorbing member 103 can be fixed. If the liquid absorbing member 103 can be fixed, “◯”; Was evaluated as “×”.

  From this result, when the ratio of the area of the support surface of the convex portion 111 to the area of the liquid absorbing member 103 (split area ratio) is 30% or more, a cap member 82 capable of fixing the liquid absorbing member 103 can be obtained. I understand.

  Next, the pressure distribution in the vicinity of the back surface of the liquid absorbing member 103 in the cap member 82 provided with the above-described branched passage 113 (recess 113A) was measured. The measurement results are schematically shown in FIG. 9 for the ¼ portion of the cap member 82.

In addition, about the magnitude | size of a negative pressure, it divides into the stage AK as follows, and the code | symbol "AL" of the corresponding stage is attached | subjected to FIG.
A: −1.0 × 10 ⁻⁰³ or less B: −1.0 × 10 ⁻⁰³ to ^−9.0 × 10 ⁻⁰⁴
C: −9.0 × 10 ⁻⁰⁴ to −8.0 × 10 ⁻⁰⁴
D: −8.0 × 10 ⁻⁰⁴ to ^−7.0 × 10 ⁻⁰⁴
E: −7.0 × 10 ⁻⁰⁴ to −6.0 × 10 ⁻⁰⁴
F: −6.0 × 10 ⁻⁰⁴ to −5.0 × 10 ⁻⁰⁴
G: −5.0 × 10 ⁻⁰⁴ to −4.0 × 10 ⁻⁰⁴
H: −4.0 × 10 ⁻⁰⁴ to −3.0 × 10 ⁻⁰⁴
I: −3.0 × 10 ⁻⁰⁴ to ^−2.0 × 10 ⁻⁰⁴
J: −2.0 × 10 ⁻⁰⁴ to ^−1.0 × 10 ⁻⁰⁴
K: −1.0 × 10 ⁻⁰⁴ to 0.0 × 10 ⁺⁰⁰

  On the other hand, for comparison, as shown in FIG. 10, a cap member 130 in which a groove 137 was formed along the longitudinal direction including the discharge port 136 at the bottom of the recess forming member 132 provided with the contact member 131 was manufactured. In the cap member 130, the back surface of the liquid absorbing member 133 is in contact with the bottom surface of the recess forming member 131. The pressure distribution in the vicinity of the back surface of the liquid absorbing member 133 was measured in the same manner for the cap member 130 of this comparative example. This measurement result is schematically shown in FIG. 11 for a quarter portion of the cap member 130. In addition, about the classification | category of the magnitude | size of a negative pressure, and its code | symbol, it is the same as that mentioned above. Moreover, since it cannot be accurately classified, a part of the categories is shown collectively.

  9 and FIG. 11 are compared, in the comparative example, there is a difference in magnitude between the negative pressure in the vicinity of the groove 137 and the negative pressure in the region away from the groove 137, but in the present embodiment, the discharge port 106 is compared. It can be seen that the difference between the negative pressure in the vicinity and the negative pressure in the region away from the discharge port 106 is relatively small.

  Therefore, when evaluating the uniformity of the pressure distribution, the ratio of the pressure obtained by dividing the pressure distribution of the liquid absorbing member by the pressure at the discharge port where the negative pressure is maximum is used as a reference. did. It can be judged that the pressure ratio is more uniform as the pressure ratio is closer to 100%.

  When this pressure ratio was calculated for the cap member 82 of this embodiment and the cap member 130 of the comparative example, the pressure ratio of the cap member 82 of this embodiment was “15.2”, whereas the cap member of the comparative example was In 130, the pressure ratio was “0.241”. From this, it can be seen that the pressure distribution of the cap member 82 of the present embodiment is relatively uniform as compared with the comparative example, which is effective for performing an efficient suction operation.

  Thus, the cap member for capping the ejection surface for ejecting droplets of the liquid ejection head, the liquid absorbing member provided in the cap member, and the suction connected to the discharge port formed at the bottom of the cap member And a convex portion that supports the liquid absorbing member is formed at the bottom of the cap member, and a passage that branches in a planar shape from the discharge port toward the outer peripheral direction is formed. By generating a negative pressure in the passage that the back side of the liquid absorbing member faces by the operation of the suction means while holding the liquid absorbing member, a substantially uniform negative pressure can be applied to the liquid absorbing member. It is possible to reduce the amount of residual liquid remaining in the absorbing member and always maintain stable discharge recovery performance.

Next, a second embodiment of the head maintenance / recovery mechanism (apparatus) according to the present invention will be described with reference to FIG. FIG. 12 is a partially perspective configuration explanatory view illustrating the configuration of the recovery mechanism.
Here, an island-shaped convex portion 121 that supports the liquid absorbing member 103 and a convex portion 122 that is partly integrated with the outer peripheral portion of the concave portion of the concave portion forming member 102 are formed at the bottom of the concave portion forming member 102 of the cap member 82. A space formed between the convex portions 121 and 122 and the liquid absorbing member 103 becomes a passage 123 (concave portion 123 </ b> A) communicating with the discharge port 106.

  In this case, the island-shaped convex portions 121 are formed in a substantially uniform spot shape. Thereby, by distributing the convex portions 121 over the entire back surface of the liquid absorbing member 103 to reliably hold the liquid absorbing member 103, the concave portions 123A are more uniformly distributed between the convex portions 121. The pressure acting on the back surface of the liquid absorbing member 103 can be made uniform.

  The island-shaped convex portion 121 is formed in a columnar shape as shown in FIG. 13 (a), but is a prismatic shape as shown in FIG. 13 (b), and a truncated cone as shown in FIG. 13 (c). The shape may be used and is not particularly limited.

  For the cap member 82, the pressure distribution in the vicinity of the back surface of the liquid absorbing member 103 was measured in the same manner as described above. This measurement result is schematically shown in FIG. 14 for a quarter portion of the cap member 82.

  Comparing FIG. 14 and FIG. 11 described above, in the comparative example, there is a difference in magnitude between the negative pressure in the vicinity of the groove 137 and the negative pressure in the region away from the groove 137, whereas in this embodiment, the discharge port 106. It can be seen that the difference between the negative pressure in the vicinity and the negative pressure in the region away from the discharge port 106 is relatively small.

  In the cap member 82 of the present embodiment, the pressure ratio is “24.9”, the pressure distribution becomes more uniform, and an efficient suction operation can be performed.

  Thus, the cap member for capping the ejection surface for ejecting droplets of the liquid ejection head, the liquid absorbing member provided in the cap member, and the suction connected to the discharge port formed at the bottom of the cap member A plurality of island-shaped convex portions that support the liquid absorbing member are formed at the bottom of the cap member, and a space formed between the plurality of island-shaped convex portions and the liquid absorbing member is formed. Since it is configured to be a passage leading to the discharge port, the liquid absorbing member is generated by generating a negative pressure in the passage facing the back side of the liquid absorbing member by the operation of the suction means while holding the liquid absorbing member by the island-shaped convex portion Thus, a substantially uniform negative pressure can be applied to the liquid absorbing member, the amount of residual liquid remaining in the liquid absorbing member can be reduced, and stable ejection recovery performance can be maintained at all times.

Next, the relationship with the viscosity of the ink (recording liquid) to be used will be described.
As described above, pigment-based inks are often used from the viewpoint of improving image quality, and the tendency to increase in viscosity is more conspicuous than dye inks. When the ink becomes highly viscous, the amount of ink remaining in the liquid absorbing member 103 gradually increases when the recording head discharge recovery process is repeatedly performed, and the water evaporates and becomes highly viscous. The absorptive performance of 103 will be rapidly deteriorated.

  Therefore, suction is performed using the cap member 82 according to the first embodiment of the present invention, the cap member 130 according to the comparative example described in FIG. 10, and ink from low viscosity to high viscosity (1 mPa · s to 15 mPa · s). The operation was performed, and the pressure distribution in the vicinity of the back surface of the liquid absorbing member at that time was examined and compared. The result is shown in FIG.

  In FIG. 15, “○” is shown when uniform suction is possible, and “X” is shown when impossible.

  From this result, when the ink viscosity is low, uniform suction is possible in both the present invention and the comparative example, but when high viscosity is reached, uniform suction is not possible in the comparative example. It can be seen that uniform suction can be continuously performed in the invention. From this result, it can be seen that the cap member according to the present invention is particularly effective when a recording liquid (ink) having a viscosity of 5 mP · s or more is used.

Next, a recording liquid (herein referred to as “ink”) used in the image forming apparatus will be described.
The ink used in the apparatus according to the present invention contains at least water, a colorant, and a wetting agent, and further contains a penetrating agent, a surfactant, and, if necessary, other components.

  Here, the ink has a surface tension at 25 ° C. of 15 to 40 mN / m, and more preferably 20 to 35 mN / m. If the surface tension is less than 15 / m, the liquid ejection head is too wet with the nozzle plate (nozzle plate) to form ink droplets (particulate), and bleeding on the paper becomes noticeable. In some cases, the ink cannot be sufficiently discharged, and if it exceeds 40 mN / m, ink permeation into the paper does not occur sufficiently, which may cause beading and a longer drying time.

  The surface tension can be measured at 25 ° C. using a platinum plate using, for example, a surface tension measuring device (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

-Colorant-
As the colorant contained in the ink, it is preferable to use at least one of a pigment, a dye, and colored fine particles.

As the colored fine particles, an aqueous dispersion of polymer fine particles containing at least one colorant of pigment and dye is preferably used.
Here, the term “containing a color material” means either or both of a state in which a color material is enclosed in polymer fine particles and a state in which the color material is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary that all the coloring material blended in the ink of the present invention is encapsulated or adsorbed in the polymer fine particles, and the coloring material may be dispersed in the emulsion. The color material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be adsorbed by the polymer, and can be appropriately selected according to the purpose.

  Further, “water-insoluble or poorly water-soluble” means that 10 parts by mass or more of the coloring material is not dissolved in 100 parts by mass of water at 20 ° C. Further, “dissolve” means that separation or sedimentation of the coloring material is not observed in the surface layer or the lower layer of the aqueous solution visually.

  The volume average particle diameter of the polymer fine particles (colored fine particles) containing a colorant is preferably 0.01 to 0.16 μm in the ink.

  Examples of the colorant include water-soluble dyes, oil-soluble dyes, disperse dyes, and the like, pigments, and the like. Oil-soluble dyes and disperse dyes are preferable from the viewpoint of good adsorptivity and encapsulation, but pigments are preferably used from the light resistance of the obtained image.

  In addition, from the viewpoint of efficiently impregnating the polymer fine particles, each of the dyes is preferably dissolved in an organic solvent, for example, a ketone solvent in an amount of 2 g / liter or more, and more preferably 20 to 600 g / liter.

  The water-soluble dye is a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye, and a food dye in the color index, and preferably has excellent water resistance and light resistance.

  In this case, examples of acid dyes and food dyes include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142; C.I. I. Acid Red 1,8,13,14,18,26,27,35,37,42,52,82,87,89,92,97,106,111,114,115,134,186,249,254 289; I. Acid Blue 9, 29, 45, 92, 249; I. Acid Black 1, 2, 7, 24, 26, 94; I. Food Yellow 3, 4; I. Food red 7, 9, 14; I. Food black 1, 2 etc. are mentioned.

  Examples of direct dyes include C.I. I. Direct yellow 1,12,24,26,33,44,50,86,120,132,142,144; I. Direct red 1,4,9,13,17,20,28,31,39,80,81,83,89,225,227; I. Direct orange 26, 29, 62, 102; I. Direct Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202; I. Direct black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, 168, 171 and the like.

  Examples of basic dyes include C.I. I. Basic yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 64, 65, 67, 70, 73, 77, 87, 91; C.I. I. Basic Red 2,12,13,14,15,18,22,23,24,27,29,35,36,38,39,46,49,51,52,54,59,68,69,70, 73, 78, 82, 102, 104, 109, 112; I. Basic blue 1,3,5,7,9,21,22,26,35,41,45,47,54,62,65,66,67,69,75,77,78,89,92,93, 105, 117, 120, 122, 124, 129, 137, 141, 147, 155; I. Basic black 2, 8 etc. are mentioned.

  Examples of reactive dyes include C.I. I. Reactive Black 3, 4, 7, 11, 12, 17; C.I. I. Reactive Yellow 1,5,11,13,14,20,21,22,25,40,47,51,55,65,67; I. Reactive Red 1,14,17,25,26,32,37,44,46,55,60,66,74,79,96,97; I. Reactive blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, and the like.

  There is no restriction | limiting in particular as said pigment, According to the objective, it can select suitably, For example, any of an inorganic pigment and an organic pigment may be sufficient.

Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is preferable. In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

  Examples of organic pigments include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable. Examples of the azo pigment include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofullerone pigments. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

  There is no restriction | limiting in particular as a color of a pigment, According to the objective, it can select suitably, For example, the thing for black, the thing for color, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

  Examples of black materials include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), titanium oxide, and the like. And organic pigments such as aniline black (CI Pigment Black 1).

  As for the color, for yellow ink, for example, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 150, 153, and the like.

  For magenta, for example, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G Lake), 83, 88, 92, 101 (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Dimethylquinacridone), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 19, and the like.

  For cyan, for example, C.I. I. Pigment Blue 1, 2, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56, 60, 63 and the like.

  In addition, as the intermediate colors for red, green and blue, C.I. I. Pigment red 177, 194, 224, C.I. I. Pigment orange 43, C.I. I. Pigment violet 3, 19, 23, 37, C.I. I. Pigment green 7, 36, and the like.

  As the pigment, a self-dispersing pigment that can be stably dispersed without using a dispersant in which at least one hydrophilic group is bonded to the surface of the pigment directly or through another atomic group is suitably used. As a result, unlike the conventional ink, a dispersant for dispersing the pigment becomes unnecessary. As the self-dispersing pigment, those having ionicity are preferable, and those having an anionic charge or those having a cationic charge are suitable.

  The volume average particle size of the self-dispersing pigment is preferably 0.01 to 0.16 μm in the ink.

Examples of the anionic hydrophilic group include —COOM, —SO ₃ M, —PO ₃ HM, —PO ₃ M ₂ , —SO ₂ NH ₂ , —SO ₂ NHCOR (where M in the formula represents hydrogen Atom, alkali metal, ammonium or organic ammonium, R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent) Is mentioned. Among these, it is preferable to use those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment.

  “M” in the hydrophilic group includes, for example, lithium, sodium, potassium and the like as an alkali metal. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium. As a method of obtaining the anionically charged color pigment, as a method of introducing —COONa to the color pigment surface, for example, a method of oxidizing the color pigment with sodium hypochlorite, a method of sulfonation, a diazonium salt The method of making it react is mentioned.

  Further, as the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, and the quaternary ammonium groups listed below are more preferable, and any of these bonded to the pigment surface is suitable as a coloring material. .

  The method for producing the cationic self-dispersing carbon black to which the hydrophilic group is bonded is not particularly limited and may be appropriately selected depending on the intended purpose. For example, N— represented by the following structural formula Examples of the method for bonding the ethylpyridyl group include a method of treating carbon black with 3-amino-N-ethylpyridinium bromide.

Here, the hydrophilic group may be bonded to the surface of the carbon black via another atomic group. Examples of other atomic groups include an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. Specific examples of the case where the above-described hydrophilic group is bonded to the surface of carbon black via another atomic group include, for example, —C ₂ H ₄ COOM (where M represents an alkali metal, quaternary ammonium), -PhSO ₃ M (where Ph represents a phenyl group, M represents an alkali metal, quaternary ammonium), -C ₅ H ₁₀ NH ₃ + and the like.

  For the ink used in the recording method according to the present invention, a pigment dispersion using a pigment dispersant can also be used.

  As the pigment dispersant, as the hydrophilic polymer compound, in the natural system, plant polymers such as gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch, alginic acid, carrageenan And seaweed polymers such as agar, animal polymers such as gelatin, casein, albumin and collagen, and microorganism polymers such as xanthene gum and dextran. In semi-synthetic systems, fiber polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, starch polymers such as sodium starch glycolate and sodium starch phosphate, sodium alginate, propylene glycol alginate And seaweed polymers such as Pure synthetic systems include polyvinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl methyl ether, non-crosslinked polyacrylamide, polyacrylic acid or alkali metal salts thereof, acrylic resins such as water-soluble styrene acrylic resins, and water-soluble styrene malees. Acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, polyvinyl pyrrolidone, polyvinyl alcohol, alkali metal salt of β-naphthalene sulfonic acid formalin condensate, cationic functional group such as quaternary ammonium and amino group Examples thereof include a polymer compound having a salt in the side chain and a natural polymer compound such as shellac. Among these, those having a carboxyl group introduced from a homopolymer of acrylic acid, methacrylic acid or styrene acrylic acid or a copolymer of a monomer having another hydrophilic group are particularly preferred as the polymer dispersant.

  Here, the weight average molecular weight of the copolymer is preferably 3,000 to 50,000, more preferably 5,000 to 30,000, and still more preferably 7,000 to 15,000.

  The mixing mass ratio of the pigment and the dispersant (pigment: dispersant) is preferably 1: 0.06 to 1: 3, and more preferably 1: 0.125 to 1: 3.

  The addition amount of the colorant in the ink is preferably 6 to 15% by mass, and more preferably 8 to 12% by mass. When the addition amount is less than 6% by mass, the image density may be lowered due to a decrease in coloring power, or feathering or bleeding may be deteriorated due to a decrease in viscosity. If the nozzle is left unattended, the nozzles will be easy to dry, non-ejection phenomenon will occur, the viscosity will be too high, the permeability will decrease, and the dots will not spread, so the image density will decrease. Or a blurred image.

-Wetting agent-
There is no restriction | limiting in particular as a wetting agent, According to the objective, it can select suitably, For example, at least 1 sort (s) selected from a polyol compound, a lactam compound, a urea compound, and saccharides is suitable.

  Here, examples of the polyol compound include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, and carbonic acid. Ethylene, and the like. These may be used alone or in combination of two or more.

  Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,3-purpandiol, 1,3-butanediol, 1,4 butanediol, and 3-methyl-1. , 3-butanediol 1,3-propanediol, 1,5-pentanediol, 1,6 hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3- Examples include butanetriol and petriol.

  Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like. .

  Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  Examples of the nitrogen-containing heterocyclic compound include N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, and ε-caprolactam.

  Examples of amides include formamide, N-methylformamide, formamide, N, N-dimethylformamide and the like.

  Examples of amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, and triethylamine.

  Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.

  Among these, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1 from the viewpoint of obtaining excellent effects on solubility and prevention of poor jetting characteristics due to water evaporation , 3-butanediol, 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol 1,3-propanediol, 1,5-pentanediol, tetraethylene glycol, 1, 6-hexanediol, 2-methyl-2,4-pentanediol, polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol, thiodiglycol, 2-pyrrolidone, N-methyl-2 -Pyrrolidone, N-hydroxyethyl-2-pi Pyrrolidone is preferred.

  Examples of the lactam compound include at least one selected from 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, and ε-caprolactam.

  Examples of the urea compound include at least one selected from urea, thiourea, ethylene urea, and 1,3-dimethyl-2-imidazolidinone. In general, the amount of urea added to the ink is preferably 0.5 to 50% by mass, and more preferably 1 to 20% by mass.

  Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and derivatives thereof. Among these, glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, and maltotriose are preferable, and maltose, sorbitol, gluconolactone, and maltose are particularly preferable.

  The above-mentioned polysaccharide means a saccharide in a broad sense and can be used to include substances widely existing in nature such as α-cyclodextrin and cellulose.

Derivatives of sugars include reducing sugars of sugars (for example, sugar alcohol (however, represented by the general formula: HOCH ₂ (CHOH) nCH ₂ OH (where n represents an integer of 2 to 5)), oxidized sugar (For example, aldonic acid, uronic acid, etc.), amino acids, thioic acid, etc. Among these, sugar alcohol is particularly preferable, and examples of the alcohol include maltitol, sorbit, and the like.

  Moreover, 10-50 mass% is preferable and, as for content in the ink of a wetting agent, 20-35 mass% is more preferable. If the content is too small, the nozzle is likely to be dried and defective ejection of droplets may occur. If the content is too large, the ink viscosity is increased, and the proper viscosity range may be exceeded.

-Penetration agent-
As the penetrant, a water-soluble organic solvent such as a polyol compound or a glycol ether compound is used. In particular, at least one of a polyol compound having 8 or more carbon atoms and a glycol ether compound is preferably used.

  Here, if the polyol compound has less than 8 carbon atoms, sufficient penetrability cannot be obtained, and the recording medium is soiled during double-sided printing, or the ink spread on the recording medium is insufficient and the pixels are filled. May deteriorate character quality and image density.

  Examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol (solubility: 4.2% (25 ° C.)), 2,2,4-trimethyl-1,3-pentanediol ( Solubility: 2.0% (25 ° C.)) is preferable.

  The glycol ether compound is not particularly limited and may be appropriately selected depending on the intended purpose.For example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetra Examples include polyhydric alcohol alkyl ethers such as ethylene glycol monomethyl ether and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  Moreover, there is no restriction | limiting in particular in the addition amount of a penetrant, Although it can select suitably according to the objective, 0.1-20 mass% is preferable and 0.5-10 mass% is more preferable.

-Surfactant-
There is no restriction | limiting in particular as said surfactant, According to the objective, it can select suitably, For example, anionic surfactant, nonionic surfactant, amphoteric surfactant, fluorine type surfactant etc. are mentioned. .

  Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.

  Examples of nonionic surfactants include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and the like.

  Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, 5-dimethyl-1-hexyn-3-ol and the like. Examples of commercially available acetylene glycol surfactants include Surfynol 104, 82, 465, 485, and TG manufactured by Air Products (USA).

  Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine. Specific examples include lauryl dimethylamine oxide, myristyl dimethylamine oxide, stearyl dimethylamine oxide, dihydroxyethyl lauryl amine oxide, polyoxyethylene coconut oil alkyl dimethyl amine oxide, dimethyl alkyl (coconut) betaine, dimethyl lauryl betaine, and the like. It is done.

  Among these surfactants, surfactants represented by the following general formulas (I), (II), (III), (IV), (V), and (VI) are preferable.

ただし、前記一般式（Ｉ）中、Ｒ１は、アルキル基を表し、炭素数６〜１４の分岐していてもよいアルキル基を表す。ｈは、３〜１２の整数を表す。Ｍは、アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、及びアルカノールアミンから選択されるいずれかを表す。

However, in the said general formula (I), R1 represents an alkyl group and represents the C6-C14 alkyl group which may be branched. h represents an integer of 3 to 12. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

ただし、前記一般式（ＩＩ）中、Ｒ２は、アルキル基を表し、炭素数５〜１６の分岐していてもよいアルキル基を表す。Ｍは、アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、及びアルカノールアミンから選択されるいずれかを表す。

However, in the said general formula (II), R2 represents an alkyl group and represents the C5-C16 alkyl group which may be branched. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

ただし、上記一般式（ＩＩＩ）中、Ｒ３は、炭化水素基を表し、例えば、分岐していてもよい炭素数６〜１４のアルキル基を表す。ｋは５〜２０の整数を表す。

However, in said general formula (III), R3 represents a hydrocarbon group, for example, the C6-C14 alkyl group which may be branched. k represents an integer of 5 to 20.

ただし、上記一般式（ＩＶ）中、Ｒ４は、炭化水素基を表し、例えば、炭素数６〜１４のアルキル基を表す。ｊは、５〜２０の整数を表す。

However, in said general formula (IV), R4 represents a hydrocarbon group, for example, a C6-C14 alkyl group. j represents an integer of 5 to 20.

ただし、上記一般式（Ｖ）中、Ｒ^６は、炭化水素基を表し、例えば、炭素数６〜１４の分岐していてもよいアルキル基を表す。Ｌ及びｐは、１〜２０の整数を表す。

However, in the general formula (V), R ⁶ represents a hydrocarbon group, for example, represents an alkyl group which may be branched having 6 to 14 carbon atoms. L and p represent an integer of 1 to 20.

ただし、上記一般式（ＶＩ）中、ｑ及びｒは０〜４０の整数を表す。

However, in said general formula (VI), q and r represent the integer of 0-40.

  Hereinafter, the surfactants of the structural formulas (I) and (II) are specifically shown in the free acid form. First, examples of the surfactant (I) include those represented by the following (I-1) to (I-6).

  Next, examples of the surfactant (II) include those represented by the following (II-1) to (II-4).

  As the fluorosurfactant, those represented by the following general formula (A) are suitable.

ただし、前記一般式（Ａ）中、ｍは、０〜１０の整数を表す。ｎは、１〜４０の整数を表す。

However, in said general formula (A), m represents the integer of 0-10. n represents an integer of 1 to 40.

  Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. And polyoxyalkylene ether polymer compounds. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain has a low foaming property, and the bioaccumulation property of a fluorine compound that has been regarded as a problem in recent years is low and highly safe. Particularly preferred.

  Here, examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like.

  Moreover, as a perfluoroalkyl carboxylic compound, perfluoroalkyl carboxylic acid, perfluoroalkyl carboxylate, etc. are mentioned, for example.

Examples of the perfluoroalkyl phosphate compound include perfluoroalkyl phosphate esters, perfluoroalkyl phosphate salts, and the like.
The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, and a polyoxyalkylene having a perfluoroalkyl ether group in the side chain. Examples thereof include sulfuric acid ester salts of ether polymers and salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group in the side chain.

Counter ions of salts in these fluorinated _{surfactants, Li, Na, K, NH4} , NH 3 CH 2 CH 2 OH, NH 2 (CH 2 CH 2 OH) 2, NH (CH 2 CH 2 OH) 3 Etc.

As a fluorine-type surfactant, what was synthesize | combined suitably may be used and a commercial item may be used.
Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.), Fullrad FC- 93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M), MegaFuck F-470, F1405, F-474 ( All manufactured by Dainippon Ink and Chemicals), Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont), FT-110, FT-250 FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), PF-151N (manufactured by Omninova), and the like. It is done. Among these, Zonyl FS-300, FSN, FSN-100, and FSO (manufactured by DuPont) are particularly preferable from the viewpoints of reliability and color development improvement.

-Other ingredients-
The other components are not particularly limited and may be appropriately selected as necessary. For example, resin emulsion, pH adjuster, antiseptic / antifungal agent, rust inhibitor, antioxidant, ultraviolet absorber, oxygen absorber Agents, light stabilizers, and the like.

-Resin emulsion-
The resin emulsion is obtained by dispersing resin fine particles in water as a continuous phase, and may contain a dispersant such as a surfactant as necessary.

  The content of resin fine particles as a dispersed phase component (content of resin fine particles in the resin emulsion) is generally preferably 10 to 70% by mass. Further, the particle diameter of the resin fine particles is preferably 10 to 1000 nm, more preferably 20 to 300 nm, particularly considering use in an ink jet recording apparatus.

  The resin fine particle component of the dispersed phase is not particularly limited and can be appropriately selected depending on the purpose. For example, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, Examples include vinyl chloride resins, acrylic styrene resins, acrylic silicone resins, and among these, acrylic silicone resins are particularly preferable.

As a resin emulsion, what was synthesize | combined suitably may be used and a commercial item may be used.
Examples of commercially available resin emulsions include microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.). Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, Seiden) Chemical Co., Ltd.), Primal AC-22, AC-61 (acrylic resin emulsion, manufactured by Rohm and Haas), Nanoacryl SBCX-2821, 3689 (acrylic silicone resin emulsion, Toyo Ink Manufacturing Co., Ltd.) Company Ltd.), # 3070 (methyl methacrylate polymer resin emulsion, manufactured by Mikuni Color Ltd.).

  The addition amount of the resin fine particle component in the resin emulsion in the ink is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass, and still more preferably 1 to 10% by mass. If the addition amount is less than 0.1% by mass, the effect of improving clogging resistance and ejection stability may not be sufficient, and if it exceeds 50% by mass, the storage stability of the ink may be reduced. There is.

  Examples of antiseptic / antifungal agents include 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, etc. Is mentioned.

  The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more without adversely affecting the ink, and any substance can be used according to the purpose.

  Examples of the pH adjusting agent include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonium hydroxide, quaternary ammonium hydroxide, Examples thereof include quaternary phosphonium hydroxide, alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate.

  Examples of the rust preventive agent include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

  Examples of phenolic antioxidants (including hindered phenolic antioxidants) include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4 , 4′-Butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) Propionyloxy] ethyl] 2,4,8,10-tetrixaspiro [5,5] undecane, 1,1,3-tris (2-methyl-4- Hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, and the like.

  Examples of amine-based antioxidants include phenyl-β-naphthylamine, α-naphthylamine, N, N′-di-sec-butyl-p-phenylenediamine, phenothiazine, N, N′-diphenyl-p-phenylenediamine, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2′-methylenebis (4 -Methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene- 3 (3,5-di-tert-butyl-4-dihydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, and the like.

  Examples of the sulfur-based antioxidant include dilauryl 3,3′-thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl β, β′-thiodipropionate, 2-mercaptobenzimidazole, dilauryl sulfide and the like can be mentioned.

  Examples of phosphorus antioxidants include triphenyl phosphite, octadecyl phosphite, triisodecyl phosphite, trilauryl trithiophosphite, and trinonylphenyl phosphite.

  Examples of the UV absorber include benzophenone UV absorbers, benzotriazole UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers, nickel complex salt UV absorbers, and the like.

  Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, and the like.

  Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- ( 2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, and the like.

  Examples of salicylate-based ultraviolet absorbers include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.

  Examples of the cyanoacrylate ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2-cyano. -3-methyl-3- (p-methoxyphenyl) acrylate, and the like.

  Examples of the nickel complex ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), 2,2′-thiobis ( 4-tert-octylferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octylferrate) triethanolamine nickel (II), and the like.

  The ink in the ink media set of the present invention comprises at least water, a colorant, and a wetting agent, and if necessary, a penetrating agent, a surfactant, and, if necessary, other components dispersed or dissolved in an aqueous medium, Produced by stirring and mixing as necessary. The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.

  The viscosity of the ink is preferably 5 mPa · s or more and 30 mPa · s or less, and more preferably 8 to 20 mPa · s at 25 ° C. If the viscosity exceeds 20 mPa · s, it may be difficult to ensure ejection stability.

  The pH of the ink is preferably 7 to 10, for example.

  There is no restriction | limiting in particular as coloring of an ink, According to the objective, it can select suitably, Yellow, magenta, cyan, black etc. are mentioned. When recording is performed using an ink set in which two or more of these colorings are used in combination, a multicolor image can be formed. When recording is performed using an ink set in which all colors are combined, a full color image is formed. be able to.

Next, an example of ink adjustment will be described. However, the present invention is not limited to this.
<Production Example 1 ink>
(Black ink)
KM-9036 (Toyo Ink) (self-dispersing pigment) 50% by weight
Glycerin 10% by weight
1,3-butanediol 15% by weight
2-ethyl-1,3-hexanediol 2% by weight
2-pyrrolidone 2% by weight
Surfactant (1-9) 1% by weight
Silicone defoamer KS508 (Shin-Etsu Chemical) 0.1% by weight
Residual amount of ion-exchanged water An ink composition having the above formulation was prepared and sufficiently stirred at room temperature, and then filtered through a membrane filter having an average pore diameter of 1.2 μm to obtain an ink of Production Example 1.

<Production Example 2 ink>
(Preparation of polymer solution A)
After sufficiently replacing nitrogen gas in the 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas introduction tube, reflux tube and dropping funnel, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate, Polyethylene glycol methacrylate 4.0 g, styrene macromer 4.0 g and mercaptoethanol 0.4 g were mixed and heated to 65 ° C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxylethyl methacrylate, 36.0 g of styrene macromer, 3.6 g of mercaptoethanol, azobismethylvaleronitrile A mixed solution of 2.4 g and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours. After dropping, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobismethylvaleronitrile was added and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50%. A part of this polymer solution was dried and measured by gel permeation chromatography (standard: polystyrene, solvent: tetrahydrofuran). The weight average molecular weight was 15000.

(Preparation of pigment-containing polymer fine particle aqueous dispersion)
28 g of polymer solution A and C.I. I. 26 g of Pigment Yellow 97, 13.6 g of a 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone and 13.6 g of ion-exchanged water were sufficiently stirred, and then kneaded using a roll mill. The obtained paste was put into 200 g of ion-exchanged water and sufficiently stirred, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain an aqueous dispersion of yellow polymer fine particles.
(Yellow ink)
Yellow polymer fine particle dispersion 40% by weight
Glycerin 8% by weight
1,3-butanediol 20% by weight
2,2,4-Trimethyl-1,3-pentanediol 2% by weight
Surfactant (1-8) 1.5% by weight
Silicone defoamer KS508 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1% by weight
Residual amount of ion-exchanged water An ink composition having the above formulation was prepared and sufficiently stirred at room temperature, followed by filtration through a membrane filter having an average pore diameter of 1.2 μm to obtain an ink of Production Example 2.

<Production Example 3 ink>
(Preparation of pigment-containing polymer fine particle aqueous dispersion)
The pigment type is C.I. I. An aqueous dispersion of magenta polymer fine particles was obtained in the same manner except that the pigment red 122 was used.
(Magenta ink)
Dispersion of magenta polymer fine particles 50% by weight
Glycerin 10% by weight
1,3-butanediol 18% by weight
2,2,4-Trimethyl-1,3-pentanediol 2% by weight
Surfactant (1-8) 1.5% by weight
Silicone defoamer KS508 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1% by weight
Residual amount of ion-exchanged water An ink composition having the above formulation was prepared and sufficiently stirred at room temperature, and then filtered through a membrane filter having an average pore size of 1.2 μm to obtain an ink of Production Example 3.

<Production Example 4 ink>
(Preparation of pigment-containing polymer fine particle aqueous dispersion)
The pigment type is C.I. I. An aqueous dispersion of cyan polymer fine particles was obtained in the same manner except that the pigment blue was changed to 15: 3.
(Cyan ink)
Cyan polymer fine particle dispersion 40% by weight
Glycerin 8% by weight
1,3-butanediol 20% by weight
2,2,4-Trimethyl-1,3-pentanediol 2% by weight
Surfactant (1-8) 1.5% by weight
Silicone defoamer KS508 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1% by weight
Residual amount of ion-exchanged water An ink composition having the above formulation was prepared and sufficiently stirred at room temperature, and then filtered through a membrane filter having an average pore size of 1.2 μm to obtain an ink of Production Example 4.

  Each ink of the above production example contained 6% by weight or more of pigment, the viscosity at 25 ° C. was about 8 mPa · s, and the surface tension at 25 ° C. was about 25 mN / m. In addition, each ink of the above production example has a viscosity increase rate (mPa · s /%) accompanying water evaporation of 1.0 or less up to a water evaporation rate of 30% with respect to the total weight of the ink, and a water evaporation rate of 30 to 30%. The average particle size of the colorant in the ink having a viscosity increase rate exceeding 50 during 45% and the viscosity increase rate exceeding 50 is not more than 5 times the initial average particle size, And it was confirmed that it became 0.8 micrometer or less.

  By using such a recording liquid, nozzle clogging does not occur even when left for a long period of time, and high image quality and high-speed printing on plain paper can be achieved. Moreover, even if the recording liquid in the nozzle is dried and thickened and cannot be discharged from the nozzle, the recording liquid does not cause the nozzle to clog due to coarse particles of the pigment. It has an advantage that it can be easily recovered by the maintenance recovery operation.

  Even when such a recording liquid is used, by adopting the configuration of the cap member described above, the negative pressure acting on the liquid absorbing member is made uniform, so that the recording discharged into the cap member. The liquid can be absorbed by the liquid absorbing member and further sucked and discharged, and the remaining recording liquid (liquid) in the cap member is reduced and moisturized by the absorbing member is also generated. Discharge failure can be prevented.

  In the above embodiment, an example in which there is one suction cap has been described. However, one or more suction caps that also serve as a moisturizer and one or more moisture retention caps for each head or fewer than the number of recording heads. The same applies to the case where a maintenance / recovery mechanism having a cap is provided.

  In each of the above embodiments, the printer configuration has been described as the image forming apparatus according to the present invention. However, the present invention is not limited to this, and can be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. Further, the present invention can also be applied to an image forming apparatus that uses a recording liquid or a fixing processing liquid that is a liquid other than ink, and other apparatuses that eject liquid droplets.

FIG. 3 is a perspective explanatory view seen from the front side showing an example of the image forming apparatus according to the present invention including the liquid ejection apparatus according to the present invention. 2 is a configuration diagram illustrating an outline of a mechanism unit of the image forming apparatus. FIG. It is principal part plane explanatory drawing of the mechanism part. FIG. 2 is an explanatory diagram for explaining a recording head of the image forming apparatus. It is a lineblock diagram showing a cap member for explanation of a 1st embodiment of a maintenance maintenance device of a head concerning the present invention by a perspective explanatory view. It is sectional explanatory drawing which follows the AA line of FIG. 5 with which it uses for description of a cap member. It is a plane explanatory view of the cap member. It is explanatory drawing with which it uses for description of the ratio of the area of the support surface of a convex part with respect to the area of the back surface of a liquid absorption member, and the fixability of a liquid absorption member. It is typical explanatory drawing with which it uses for description of the pressure distribution of the back surface of the liquid absorption member of the cap member. It is an isometric view explanatory drawing of the cap member with which it uses for description of a comparative example. It is typical explanatory drawing with which it uses for description of the pressure distribution of the back of the liquid absorption member of the cap member of the comparative example. It is a lineblock diagram showing a cap member for explanation of a 2nd embodiment of a maintenance maintenance device of a head concerning the present invention by a perspective explanatory view. It is explanatory drawing which shows the example from which the shape of the island-shaped convex part of the cap member differs. It is typical explanatory drawing with which it uses for description of the pressure distribution of the back surface of the liquid absorption member of the cap member. It is explanatory drawing with which it uses for description of the evaluation of the uniformity of the pressure distribution with respect to an ink viscosity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Ink cartridge 33 ... Carriage 34 ... Recording head 81 ... Maintenance recovery mechanism 82 ... Cap member 101 ... Contact member 101a ... Contact part 102 ... Recess formation member 103 ... Liquid absorption member 106 ... Discharge port (suction hole)
108 ... Suction pump 111 ... Convex part 113 ... Passage 113A ... Concave part 121 ... Convex part 123 ... Passage 123A ... Concave part

Claims (6)

A cap member for capping the ejection surface for ejecting droplets of the liquid ejection head;
A liquid absorbing member provided in the cap member;
A suction means connected to a discharge port formed at the bottom of the cap member,
The cap member has a quadrangular shape when viewed in a plane, and the discharge port is provided at the center of the bottom.
A convex portion including a plurality of island-shaped convex portions that support the liquid absorbing member is formed on the bottom portion of the cap member, and a space formed between the convex portion and the liquid absorbing member is the drain. It becomes a passage leading to the exit,
The passage, in plan view, Ri shape der that branches radially towards the said discharge port in the outer peripheral direction of the rectangular four corners,
The plurality of island-shaped convex portions are formed between the plurality of branched passages, and the passage is formed so as to surround the plurality of island-shaped convex portions. A head maintenance and recovery device. 2. The head maintenance / recovery device according to claim 1 , wherein the area of the support surface of the convex portion is 30% or more of the area of the liquid absorbing member. 3. The head maintenance / recovery device according to claim 1, wherein the liquid discharge head includes a plurality of nozzle rows that discharge different color liquids or a plurality of liquid discharge heads that discharge different color liquids. A head maintenance / recovery device. A liquid discharge apparatus for discharging droplets from a liquid ejecting head, a liquid discharge apparatus characterized in that it comprises a maintenance and recovery device of a head according to any one of claims 1 to 3. 4. An image forming apparatus for forming an image by ejecting liquid droplets from a liquid ejection head, comprising the head maintenance / recovery device according to any one of claims 1 to 3 . 6. The image forming apparatus according to claim 5 , wherein the recording liquid contains at least water, a colorant, and a wetting agent and has a viscosity at 25 ° C. of 5 to 30 mPa · s.

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