JP2005161803A - Capping mechanism and ink-jet recording device using the same mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capping mechanism of ink-jet recording device capable of securing a sealing performance while improving the nozzle resistance against the noise such as level-difference and waviness of contact surface, and of preventing the leakage due to cap-deformation caused by vacuum in the cap. <P>SOLUTION: At the cap of rubber-like elastic material which is contacted to the discharge port face of recording means discharging an ink, a ring-shaped contact section 32 capable of contacting to the discharge port face 28 with the sealed state is formed at the end of a side wall section 31 of the cap 23. The contact-face pressure distribution of the contact section is made ununiform in the direction which intersects the extending direction of the side wall section by making the contact section to be a slope inclined toward the width direction or forming a rib 32a consisting of ring-shaped protruded stripes at the contact section. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a capping mechanism having a cap made of a rubber-like elastic material that comes into contact with an ejection port surface to cover an ejection port of a recording unit that ejects ink, and an ink jet recording apparatus using the capping mechanism.

  2. Description of the Related Art Conventionally, recording apparatuses that perform recording on recording media such as paper, cloth, plastic sheets, OHP sheets (hereinafter also simply referred to as “recording paper”) have various recording methods (for example, wire dot method, thermal method, It has been proposed as a form capable of mounting a recording head by a thermal transfer method or an ink jet method. Among such recording apparatuses, an ink jet recording type recording apparatus (hereinafter referred to as an ink jet recording apparatus) that performs recording on recording paper by discharging ink from an ejection port (nozzle) is a low-noise non-impact recording apparatus. High-density and high-speed recording operation is possible.

  The ink jet recording apparatus is an extremely excellent recording method having a simple configuration, but there are also disadvantages. One disadvantage is discharge failure (including non-discharge). The ejection failure is a phenomenon in which ink droplets are actually not ejected or the ejection state is deteriorated in spite of sending an ejection signal to the recording head. There are about three causes of the discharge failure in the vicinity of the discharge port of the ink jet recording head. One is that the viscosity of the ink at the discharge port becomes high due to evaporation of the solvent from the discharge port surface, and the discharge is performed at a predetermined pressure. Disappear. The other is when fine debris in the ink liquid enters the discharge port and obstructs the discharge, and the other is that the air dissolved in the ink liquid dissolves in the head and forms bubbles. This is a case where pressure for discharging is absorbed.

  As a solution to the above technical problem, a capping mechanism is provided to cover a discharge port by bringing a cap formed of a viscoelastic material (rubber-like elastic material) such as rubber into close contact with the discharge port surface, and a solvent from the discharge port. It is done to prevent evaporation and debris adhesion. Further, a suction recovery means is provided for sucking out the thickened ink, fine dust, bubbles, etc. in the head flow path from the discharge port together with the ink by generating a negative pressure in the cap in close contact with the discharge port surface. This is also widely done. The cap of the capping means is required to have a sealing performance that seals the inside by closely contacting the discharge port surface during capping. For this reason, the cap tip contact part is made of soft rubber or elastomer or other viscoelastic material so that it adheres to the discharge port surface even when dust or dirt adheres to it or when there is a level difference due to the manufacture of the recording head. By doing so, a structure that is easily elastically deformed in a direction orthogonal to the discharge port surface is also made.

  Basically, the cap can be sealed by pressing firmly against the surface of the discharge port, but if the pressing force is increased, problems other than sealing will occur. For example, it is necessary to enlarge each component in order to suppress the stress and deformation amount of the cap, the inkjet head, and the members that support them. Further, a powerful motor is required to cope with an increase in the load on the drive system, and the power consumption increases. Furthermore, wear of sliding parts such as bearings and gear tooth surfaces also increases. That is, the preferable cap configuration is not only high sealing performance (sealing performance) but also reliable sealing with a smaller cap pressing force. Further, it is necessary that the amount of deformation due to the negative pressure in the cap during suction is small, and the sealing performance is not impaired by the deformation.

  Therefore, it is required to facilitate the deformation of the cap tip abutting portion in the direction perpendicular to the discharge port surface. For this reason, the followability to the discharge port surface is improved and the sealing performance (sealability) is required. Various cap shapes have been proposed for enhancing the above. In JP-A-5-318752, in order to ensure the adhesion between the discharge port surface and the cap tip contact portion without increasing the pressing force of the cap, the height of the side wall portion is set according to the contact state. It is described to change. Japanese Patent Application Laid-Open No. 5-77433 describes that a cap is made to have a widening trumpet shape to ensure followability to the discharge port surface. It is also true that when the side wall portion of the cap is narrowed, the contact pressure of the contact portion increases and the sealing performance is improved. On the other hand, on the other hand, the side wall portion is thicker and thicker) to widen the contact surface. By doing so, when fine foreign matters such as paper dust and dust adhere to the contact surface, they may be covered with the contact surface to ensure sealing performance. That is, if the width of the tip contact surface is widened, there is a situation in which noise resistance against processing errors and deformations is enhanced.

  Furthermore, some proposals have been made to prevent the cap from being deformed inward due to the negative pressure during suction to impair the sealing performance. In Japanese Patent Application Laid-Open Nos. H5-131639 and H11-179927, an annular soft seal member molded separately from an elastic material is attached to the side wall of the cap, thereby ensuring rigidity of the entire cap and the side wall. The structure which balances the sealing performance of a front end surface is proposed. Japanese Patent Application Laid-Open No. 2000-062201 proposes a structure in which the cap has an upper and lower two-stage structure in order to prevent the cap from falling inside the side wall portion during suction. That is, it has been proposed to have a two-stage structure of a lower part containing a core material to prevent inward deformation and an upper part not containing a core material in order to ensure followability to the discharge port surface.

As described above, the following known documents can be cited as documents that disclose the background art of the present invention.
JP-A-5-318752 JP-A-5-77433 Japanese Patent Laid-Open No. 5-131539 Japanese Patent Laid-Open No. 11-179927 JP 2000-062201 A

  However, the conventional example still has some disadvantages. In the capping mechanism described in JP-A-5-318752, the pressure contact force is made uniform by changing the height of the side wall portion according to the contact state of the tip contact portion of the cap. In such a configuration, if the force for pressing the cap against the discharge port surface is weakened as much as possible, the contact area becomes narrow, and there is an inconvenience that the airtightness is likely to be impaired by paper dust or the like. In the capping mechanism described in Japanese Patent Application Laid-Open No. 5-77433, the cap is made to have a tapered shape to improve the followability to the discharge port surface. As a result, the trumpet-shaped portions are pulled together in the vertical and horizontal directions, the shape of the tip contact portion during capping becomes unstable, and the sealing performance may be impaired.

  Further, in the capping mechanism described in Japanese Patent Application Laid-Open Nos. H5-131639 and H11-179927, even if a minute deformation can be absorbed by the tip contact portion (rib tip portion) of the side wall portion, There was an inconvenience that it was not possible to sufficiently follow the inclination and large swell of the entire cap. Further, in the capping mechanism described in Japanese Patent Application Laid-Open No. 2000-062201, the upper and lower two-stage structure is used to prevent the peripheral wall portion from falling to the inside during suction. The lower part containing the material does not need to be originally made of a rubber material, and the problem of compatibility between the adhesion performance of the upper part and the fall-preventing performance remains.

  The present invention has been made in view of the technical problems as described above, and an object of the present invention is to ensure a sealing property with a simple configuration and to have nozzle resistance against noise such as a step on the contact surface and waviness. It is possible to provide a capping mechanism that can increase the pressure and prevent leakage due to deformation of the cap due to negative pressure in the cap, and an ink jet recording apparatus using the capping mechanism.

  In order to achieve the above object, the present invention provides a capping mechanism having an elastic material cap that abuts against the ejection port surface to cover the ejection port of the recording means for ejecting ink, or an ink jet recording apparatus using the capping mechanism. An annular contact portion capable of sealingly contacting the discharge port surface is formed at the tip of the side wall portion of the cap, and the distribution of the contact surface pressure of the contact portion is an extension of the side wall portion. It is characterized by non-uniformity in a direction crossing the current direction.

  According to the present invention, since the distribution of the contact surface pressure of the tip contact portion of the cap is non-uniform in the direction intersecting the extending direction of the side wall portion of the cap, the width of the tip contact portion of the cap It is possible to distribute the contact pressure so that the high and low contact portions are ring-shaped while maintaining the resistance, thereby ensuring the sealing performance and resistance to noise such as steps on the contact surface and waviness. The nozzle property can be enhanced, and leakage due to the deformation of the cap due to the negative pressure in the cap can be prevented.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 9 is a schematic perspective view showing the configuration of an ink jet recording apparatus suitable for applying the present invention. In FIG. 9, the ink jet recording apparatus 100 is provided with a head moving mechanism 14 that reciprocally moves a recording head 19 as a recording means in a double arrow X direction. The reciprocating movement of the recording head 19 is called main scanning, and the reciprocating direction is called main scanning direction. In addition, a recording medium transport mechanism 11 is provided for transporting (paper feeding) a sheet-like recording medium S such as recording paper in an arrow Y direction that intersects (for example, orthogonally) the main scanning direction. A direction intersecting with the main scanning direction is referred to as a sub-scanning direction.

  The recording medium transport mechanism 11 includes a pair of transport rollers 12 disposed in the main scanning direction, a pair of transport rollers (paper discharge rollers) 13 disposed downstream of the transport rollers 12 in the transport direction, and transport rollers. And a transport motor M2 (not shown) that drives the motor 12. The two pairs of transport rollers 12 and 13 are synchronously driven by driving one transport roller 12 by a transport motor M2, and transport the recording sheet S as a recording medium in the arrow Y direction (sub-scanning direction) (paper feed). ) The head moving mechanism 14 includes a guide shaft 15 that guides the main scanning movement of the recording head 19 as recording means, an endless wire (or an endless belt) 18 stretched over the motor pulley 17a and the driven pulley 17b, and a motor pulley 17a. A carriage motor M1 that rotates the carriage. Then, the carriage 16 can be reciprocated along the guide shaft 15 via the endless wire (or endless belt) 18 by driving the carriage motor M1.

  A recording head 19 as recording means is detachably mounted on the carriage 16. The illustrated recording head 19 is for recording a color image, and has four recording heads (a black recording head 19A, a cyan recording head 19B, a magenta recording head 19C, and a yellow ink corresponding to ink of each color of cyan, magenta, yellow, and black. The recording head 19D). On the surface of each recording head 19 facing the recording sheet S, there is provided an ejection port array formed by arranging a plurality of ejection ports at a predetermined pitch in the sub-scanning direction. The illustrated recording head 19 includes an electrothermal converter in each discharge port. The electrothermal converter is driven to generate heat, thereby causing the ink in the discharge port to boil and use the energy generated by the film boiling. Ink is ejected from the ejection port.

  In FIG. 9, the ink ejection performance of the recording head 19 is set at a predetermined position (for example, the carriage home position) within the moving range of the carriage 16 and out of the recording area (for example, the area through which the recording sheet S is passed). A recovery device 200 that performs a recovery process for maintaining and recovering is provided. The illustrated recovery device 200 includes four caps 20 (20A, 20B, 20C, 20D) corresponding to the four recording heads 19, and a suction pump 21 as a negative pressure generation source connected to the cap 20. And a wiper 22 for wiping and cleaning (wiping) the discharge port surface of each recording head 19.

  That is, in the recovery device 200, when recording is not performed, a capping mechanism for covering the ejection port of the recording head 19 with the cap 20 to prevent ink evaporation from the ejection port and protecting the ejection port surface, and ejection port By activating the suction pump 21 in a capped state and generating a negative pressure in the cap inner space, the suction port surface is wiped by the wiper 22 with a suction recovery mechanism for sucking ink from the discharge port. A recovery processing mechanism such as a wiping mechanism for wiping off and cleaning foreign matters such as adhered ink and dust is provided. The wiper 22 is made of an elastic material such as a plate-like rubber, and is provided in the vicinity of the cap 20 so as to be selectively accessible in and out of the main scanning movement path of the recording head 19.

  FIG. 1 is a schematic longitudinal sectional view showing Embodiment 1 of a capping mechanism of an ink jet recording apparatus to which the present invention is applied. In FIG. 1, the cap unit 20 includes a cap 23 and a cap holder 24, and the cap 23 is attached to the cap holder 24. The cap 23 is made of a molded article of a rubber or thermoplastic elastomer having gas barrier properties and viscoelasticity, for example, an elastic material such as chlorinated butyl rubber or EPDM. The cap holder 24 is made of a hard resin material having excellent solvent resistance such as polyacetal. A compression coil spring (cap spring) 25 is mounted between the cap holder 24 and a holder support member (not shown), and the cap holder 24 is swingably supported on the holder support member. A cap absorber 26 for controlling the flow of ink in the cap is loaded in the internal space of the cap 23. The cap absorber 26 is formed of, for example, a resin porous body.

  FIG. 1A shows the cap open state in which the cap 23 is separated from the discharge port surface 28 of the recording head 19, and FIG. 1B shows the cap 23 in close contact with the discharge port surface 28 of the recording head 19. Indicates the capping state. On the discharge port surface 28, there is formed a discharge port array configured by arranging a plurality of discharge ports at a predetermined pitch. In FIG. 1, the cap holder 24 is provided with two through holes 27 communicating with the inside of the cap 23, and a tube is connected to each of these through holes. One of the tubes is a suction pump as a negative pressure generating source. The other tube is connected to an open / close valve (atmospheric communication valve) (not shown).

  Therefore, in the state where the tip contact portion (contact surface) 32 of the side wall portion (peripheral wall portion) 31 of the cap 23 is in contact (contact) with the discharge port surface 28 of the recording head 19, the above-described opening / closing valve (not shown) is operated. When the suction pump 21 is closed and the suction pump 21 is operated, the internal space of the cap 23 is in a negative pressure state, so that ink is sucked out from the ejection port of the recording head 19. When the on-off valve (not shown) is opened when a predetermined amount of ink has been sucked out, the resistance when sucking air from the on-off valve is smaller than the resistance when sucking ink from the discharge port. Ink suction from the ink is stopped, and the cap 23 is filled with air. This completes the suction recovery operation, which is an ink suction operation.

  As shown to (a) of FIG. 1, the contact part 32 formed cyclically | annularly along the front end surface of the side wall part 31 of the cap 23 becomes the direction which becomes low toward the inner side from the outer side in the width direction of an applicable contact part. It is inclined to. That is, in the present embodiment, the discharge port surface becomes closer to the inside of the cap 23 so that the distribution of the contact surface pressure of the contact portion 32 becomes non-uniform in the direction intersecting the extending direction of the side wall portion 31. It is formed with a slope that moves away from 28. In this case, the degree of inclination is selected such that it contacts the discharge port surface 28 up to the innermost edge of the width of the contact portion 32 in the close contact state of FIG. Due to this inclination, the contact pressure distribution (surface pressure distribution) in the width direction of the contact portion 32 becomes non-uniform when the cap 23 is pressed against the discharge port surface 28 of the recording head 19. That is, the contact pressure is high on the outside and low on the inside. In one embodiment by the present inventors, good results were obtained by setting the inclination angle in the width direction of the tip contact surface 32 in FIG. 1A to about 7 degrees. However, the appropriate value of the inclination angle varies depending on the shape and size of the cap 23, the hardness of the material of the cap 23, the pressing force of the cap 23, and the like, and is selected so as to be in close contact with the entire width of the tip contact surface 32 during pressure contact. It is preferable.

  Thus, the distribution of the contact pressure is formed in an annular shape so that the outer contact pressure is high and the inner contact pressure is low. At this time, the portion where the outside contact pressure is high has a high sealing performance (sealing property) against noise such as a step or swell of the discharge port surface 28 or a swell caused by molding accuracy of the tip portion of the side wall portion of the cap 23. Demonstrate. On the other hand, the portion where the inner contact pressure is low serves to cover fine foreign matters such as paper dust and dust adhering to the contact surface. That is, if the width of the contact surface is made narrow (narrow) in order to increase the contact pressure, the sealing performance may be impaired when paper dust or dust adheres. While maintaining a sufficient width, it is possible to maintain the function of covering the deposit and ensuring the sealing performance. That is, by making the contact surface wide, the sealing performance against noises of minute foreign matters can be improved.

  Even if the flat portion of the tip contact portion 32 is set to be in close contact with the discharge port surface 28 of the recording head 19, the slight inclination between the discharge port surface 28 and the cap 23, the discharge port Even when the discharge port surface 28 and the contact portion 32 are slightly separated due to the undulation caused by the planar accuracy of the surface 28 and the contact surface 32, the outer region of the contact portion 32 is in an annular contact (adhesion) ) And sufficient sealing performance can be secured. Moreover, if the inside of the cap 23 is set to a negative pressure for suction recovery processing or the like, the difference from the atmospheric pressure works as a pressing force, so that even if there is a slightly floating part, it will be in close contact with that part. Act on. Further, since the side wall portion (peripheral wall portion) 31 is not thinned toward the tip, the side wall portion 31 and the tip end portion have high bending rigidity, and the inside of the side wall portion 31 is caused by negative pressure in the cap during suction. Can be prevented from being deformed.

  FIG. 2 is an external perspective view of the cap 23 according to the present embodiment. In FIG. 2, the contact surface of the annular tip contact portion 32 is inclined so that the inner side is lowered as described above, so that the distribution of the contact surface pressure of the corresponding contact portion 32 is the extending direction of the side wall portion 31. It is configured to be non-uniform in the direction intersecting with. Since the inclined surface circulates around the tip contact portion 32 in an annular shape, the inclined surface is formed as a smoothly continuous inclined surface even at four corners when the cap 23 is viewed from above.

  3 is a longitudinal sectional view showing in detail the cross-sectional shape in the width direction of the tip abutting portion 32 of the cap 23 of FIG. 2, and (a) is an enlarged longitudinal sectional view of the abutting portion 32 in FIG. (B) is an enlarged longitudinal sectional view when the inner and outer corners (both shoulders) of the contact part 32 are formed in an R shape (round shape). In FIG. 3A, the corners at both the inner and outer ends of the contact portion 32 are square. However, in actuality, when a cap is molded using a mold, the corners of the side wall 31 are corners of the mold, so that it is difficult to accurately mold sharp corners above a certain level. . Therefore, actually, as shown in FIG. 3B, the corners on both sides of the abutting portion 32 have an R shape (round shape) having a small radius. In FIG. 3B, for example, when the width of the contact portion 32 is about 1.5 mm, the arc radius of both shoulder portions is selected to be about 0.3 mm. Also, from the viewpoint of manufacturing a mold for molding, it is easier to manufacture a mold if the corners of the contact portion 32 of the cap 23 are R-shaped, and the surface of the side wall 31 of the cap 23 is smooth. The degree can be easily secured.

  FIG. 4 is an enlarged longitudinal sectional view showing another configuration example of the tip portion of the annular side wall portion 31 of the cap 23 according to the first embodiment of the present invention. In the cap 23 of FIG. 4, the cross-sectional shape of the side wall part 31 is comprised so that it may become thin toward the front-end | tip part. According to such a configuration, since the tip end portion becomes thin and the falling strength of the side wall portion 31 decreases, the effect of preventing the side wall portion 31 from falling against the negative pressure in the cap is reduced to some extent, but the contact portion 32 is not provided. By using the inclined surface, the adhesion effect when the negative pressure in the cap is generated can be further improved.

  That is, according to the capping mechanism of the ink jet recording apparatus described with reference to FIGS. 1 to 4, the distribution of the contact surface pressure of the tip contact portion 32 of the cap 23 is in a direction crossing the extending direction of the side wall portion 31 of the cap. By adopting a non-uniform configuration, the abutment pressure is distributed so that the high and low abutment portions are annular while ensuring the width of the tip abutment portion 32 of the cap 23 to ensure sealing performance. In addition, it is possible to improve the nozzle resistance against noise such as a step on the contact surface and swell, and to prevent leakage due to deformation of the cap due to negative pressure in the cap.

  FIG. 5 is a partially enlarged vertical cross-sectional view showing a cross-sectional shape in the width direction of the tip of the cap according to the second embodiment. In the present embodiment, the annular tip contact portion 32 of the cap 23 is formed with a slope inclined so that the outside is lowered, so that the distribution of the contact surface pressure of the corresponding contact portion 32 extends the side wall portion 31. It is configured to be non-uniform in a direction that intersects the direction. If the inclination in the direction in which the outer side is lowered in this way, the contact effect of the contact portion 32 when the negative pressure in the cap is applied is reduced, but the effect of preventing the sidewall portion from collapsing due to the thickness of the side wall portion 31 is reduced. It is possible to ensure the sealing property (sealing effect) of the high surface pressure portion (inner region) due to the non-uniformity of the contact pressure. The second embodiment of FIG. 5 is different from the first embodiment described in FIGS. 1 to 4 in the above points, but has substantially the same configuration in other points. The same effects as in the first embodiment can be obtained.

  FIG. 6 is a schematic longitudinal sectional view showing Embodiment 3 of the capping mechanism of the ink jet recording apparatus to which the present invention is applied. In FIG. 6, an annular rib (projection strip) 32 a made of a projection strip is formed on the outermost peripheral side (width direction outer side) of the annular tip contact portion 32 of the cap 23. The rib 32a is formed over the entire circumference of the annular tip contact surface 32 of the cap 23. Therefore, in this embodiment, the distribution of the contact surface pressure of the contact portion 32 is provided by providing the rib 32a. Is configured to be non-uniform in the direction intersecting the extending direction of the side wall portion 31. The third embodiment of FIG. 6 is different from the first embodiment described with reference to FIGS. 1 to 4 in the above points, but has substantially the same configuration in other points, and corresponding parts (same functions). And the detailed description thereof will be omitted.

  In this embodiment, the tip contact surface 32 of the cap 23 is basically parallel to the discharge port surface 28 of the recording head 19. A rib 32a having a protruding cross section is formed on the outermost side of the tip contact surface 32, and this rib 32a corresponds to the contact portion 32 formed of the inclined surface of the first embodiment. In this embodiment, the rib 32a of the protrusion is provided in an annular shape over the entire circumference of the abutment portion 32, and a high sealing portion due to high surface pressure and a portion having a large area while having low surface pressure are clear. It is divided into. Therefore, according to the present embodiment, the size and shape of the cross-sectional shape of the rib 32a can be easily selected as a value for optimization according to the characteristics of each part.

  In the present embodiment, it may be configured such that only the rib (projection strip) 32a formed of an annular minute projection is brought into contact with the discharge port surface 28, and this configuration also increases the width of the tip contact surface 32. In addition, it is possible to secure the sealing performance by increasing the contact pressure. However, in a normal configuration, since the side edge region (the inner region in the illustrated example) where the minute protrusions (ribs) 32a of the contact portion 32 do not exist is also in contact, the discharge port surface of the contact portion 32 The contact width to 28 can be widened. Therefore, it is possible to effectively prevent the side wall portion 31 from falling inward due to the suction negative pressure in the cap 23. Accordingly, in this embodiment as well, in the same manner as in the first embodiment, the contact pressure is distributed so that the portion where the contact pressure is high and the portion where the contact pressure is low are annular while the width of the tip contact portion 32 is secured. As a result, the sealing performance can be secured, the nozzle resistance against noise such as a step on the contact surface and waviness can be improved, and leakage due to the deformation of the cap due to the negative pressure in the cap can be prevented.

  FIG. 7 is a schematic longitudinal sectional view showing an enlarged cross section in the width direction of the tip contact portion 32 of the cap 23 according to the fourth embodiment. In Example 4 of FIG. 7, a plurality of ribs (projections) 32 a are formed on the tip contact portion 32 of the cap 23. Each of the plurality of ribs 32a is formed as a protrusion (rib) having a micro-projection cross section having a concentric annular shape (usually a rectangle with rounded corners instead of a circle) like the rib 32a in the third embodiment (FIG. 6). ing. Thus, the tip contact surface 32 of the multi-projection having a plurality of concentric annular ribs 32a is formed. In other words, in the present embodiment, by providing a plurality of concentric annular ribs 32 a, the distribution of the contact surface pressure of the contact portion 32 is configured to be non-uniform in the direction intersecting the extending direction of the side wall portion 31. ing. The present embodiment is different from the first embodiment described with reference to FIGS. 1 to 4 in the above points, but has substantially the same configuration in other points.

  In FIG. 7, the plane connecting the vertices of the plurality of ribs 32 a is parallel to the ejection port surface 28 of the recording head 19. By comprising in this way, in order to suppress the deformation | transformation by the negative pressure in a cap at the time of attraction | suction, while making the width | variety of the contact surface 32 wide, the contact pressure of a contact part can be kept high. In addition, since a plurality of contact portions are formed in a concentric ring shape, it is possible to maintain good sealing performance when paper dust or dust adheres to the contact surface. Further, in the present embodiment, among the plurality of ribs 32 a formed in the contact portion 32, the outermost and innermost ribs are arranged so as to form the outer and inner shoulder portions of the contact portion 32. Yes. According to such a configuration, the distribution in the width direction of the contact surface pressure can be made high and low while closely contacting the discharge port surface 28 with the entire width (all regions) of the tip contact surface 32. Therefore, also in this embodiment, as in the case of each of the above-described embodiments, it is possible to ensure the sealing performance and to improve the nozzle resistance against noise such as a step on the contact surface and swell, and further, the negative pressure in the cap. Leakage caused by deformation of the cap due to can be prevented.

  FIG. 8 is a schematic longitudinal sectional view showing an enlarged cross section in the width direction of the tip contact portion of the cap 23 according to the fifth embodiment. In the fifth embodiment shown in FIG. 8, the tip contact portion 32 of the cap 23 has a multi-layer structure made of two types of elastic materials such as rubber having different hardness. In FIG. 8, a soft material portion 33 made of an elastic material having a rubber hardness lower than that of the main body portion of the cap 23 is provided at the contact portion 32 of the cap 23. The cap 23 is formed of an integrally molded product, but the boundary surface between the soft material portion 33 and the main body portion (or the side wall portion 31) of the cap 23 is along the direction in which the corresponding contact portion extends to the tip contact portion 32. It is formed in a ring shape. That is, in this embodiment, the contact portion 32 is formed in a plurality of regions having different hardnesses so that the distribution of the contact surface pressure of the contact portion 32 is not in the direction intersecting the extending direction of the side wall portion 31. It is configured to be uniform. The present embodiment differs from the first embodiment described with reference to FIGS. 1 to 4 in the points described above, but has substantially the same configuration in other points.

  According to the fifth embodiment of FIG. 8, when the cap 23 is brought into contact with the ejection port surface 28 of the recording head 19, a portion with a high contact pressure is generated in an annular shape in the outer region of the contact portion 32. A portion where the pressure is low occurs in a ring shape in the inner region of the contact portion 32. By configuring in this way, the distribution of the contact surface pressure of the corresponding contact portion 32 is changed in the width direction (that is, as in the above-described embodiments, while maintaining the symmetry of the cross-sectional shape of the tip contact portion 32. A configuration that is non-uniform in the direction intersecting the extending direction of the side wall portion 31 can be realized. Therefore, this embodiment can provide the same effects as those of the above-described embodiments. In particular, according to the present embodiment, even when the force pressing the cap 23 against the discharge port surface 28 is slightly small, the full width of the tip contact portion 32 of the cap 23 can be easily brought into close contact with the discharge port surface 28. In the illustrated embodiment, the tip contact portion 32 has a multi-layered structure made of two types of rubber-like elastic materials having different hardnesses. However, if necessary, this may be achieved by using three or more types of rubbers having different hardnesses. Alternatively, a multi-layer structure made of an elastic material may be used.

  According to the embodiment described above, since the high pressure portion and the low pressure portion of the contact pressure distribution of the abutting portion 32 of the cap 23 are formed in an annular shape, the high pressure portion is sealed against negative pressure in the cap or the like. (Sealability) can be ensured, and noise resistance against processing accuracy and foreign matter adhesion can be enhanced at low pressure parts. In addition, the cap 23 can be easily formed by forming the abutting portion 32 as an inclined surface in the width direction so as to have an asymmetric cross-sectional shape. Further, by adopting a configuration in which the contact pressure is increased at the outer portion in the width direction of the contact portion 32, it is possible to improve the adhesion when a negative pressure is applied in the cap. Further, the contact pressure distribution in the width direction of the tip contact portion 32 is made to be high and low, and the entire contact width is in close contact, so that the side wall portion (or the peripheral wall portion) 31 of the cap 23 is inward due to the negative pressure in the cap. Can be effectively prevented.

  In the above embodiment, the serial recording type inkjet recording apparatus that performs recording while moving the recording head relative to the recording material has been described as an example. The present invention can be similarly applied to a line recording type ink jet recording apparatus that records only by sub-scanning using a line type recording head of a length that covers a part, and can achieve the same effect. is there. The present invention also provides a gradation using a recording apparatus using one recording head, a color recording apparatus using a plurality of recording heads that record with different color inks, or a plurality of recording heads that record with the same color and different densities. The present invention can be similarly applied to a recording apparatus and further to a recording apparatus that combines these, and the same effect can be achieved.

  Furthermore, the present invention relates to a recording head including a configuration using a replaceable ink cartridge in which a recording head and an ink tank are integrated, a configuration in which the recording head and the ink tank are separated, and a connection between them using an ink supply tube or the like. The present invention can be similarly applied to any arrangement of the ink tank, and the same effect can be obtained. The present invention can also be applied to a case where the ink jet recording apparatus uses a recording means that uses an electromechanical transducer such as a piezo element. In particular, the ink is ejected using thermal energy. In the ink jet recording apparatus using the recording means of the above system, an excellent effect is brought about. This is because such a system can achieve higher recording density and higher definition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view showing Embodiment 1 of a capping mechanism of an ink jet recording apparatus to which the present invention is applied, wherein (a) shows an open state in which a cap is separated from a discharge port surface, and (b) shows discharge of the cap. The capping state in close contact with the exit surface is shown. It is a typical perspective view which shows the structure of the cap unit in FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially enlarged longitudinal sectional view showing a front end abutting portion of a cap according to Embodiment 1 of the present invention in a cross-section in the width direction. (B) shows a case where both end portions in the width direction of the tip contact portion are formed in an R (round) shape with a small radius of curvature. It is a partial expanded longitudinal cross-sectional view which shows another structural example of the front-end | tip contact | abutting part of the cap which concerns on Example 1 of this invention in cross section in the width direction. It is a partial expanded longitudinal cross-sectional view which shows the front-end | tip contact part of the cap which concerns on Example 2 of this invention in cross section in the width direction. FIG. 9 is a schematic longitudinal sectional view illustrating a capping mechanism of an ink jet recording apparatus to which the present invention is applied, according to a third embodiment, in which (a) shows an open state in which the cap is separated from the discharge port surface, and (b) shows discharge of the cap. The capping state in close contact with the exit surface is shown. It is a partial expanded longitudinal cross-sectional view which shows the front-end | tip contact part of the cap which concerns on Example 4 of this invention in cross section in the width direction. It is a partial expanded longitudinal cross-sectional view which shows the front-end | tip contact part of the cap which concerns on Example 5 of this invention in cross section in the width direction. 1 is a schematic perspective view showing a configuration of an ink jet recording apparatus provided with a capping mechanism suitable for applying the present invention.

Explanation of symbols

11 Recording medium transport mechanism 12 Transport roller 13 Transport roller (paper discharge roller)
DESCRIPTION OF SYMBOLS 14 Head moving mechanism 15 Guide shaft 16 Carriage 17a Motor pulley 17b Idler pulley 18 Endless wire 19 Recording means (recording head)
20 Cap unit 21 Negative pressure source (suction pump)
22 Wiper 23 Cap 24 Cap Holder 25 Cap Spring 26 Cap Absorber 27 Through Hole 28 Discharge Port Surface 31 Side Wall (Cap)
32 Tip contact part (tip contact surface)
32a rib (protrusion)
33 Soft material part 100 Inkjet recording device 200 Recovery device S Recording medium (recording sheet, recording paper)
M1 Carriage motor

Claims (13)

In a capping mechanism of an ink jet recording apparatus having a cap made of an elastic material in contact with an ejection port surface to cover an ejection port of a recording unit that ejects ink,
An annular contact portion that can contact the discharge port surface in a sealed state is formed at the tip of the side wall portion of the cap, and the distribution of the contact surface pressure of the contact portion is the direction in which the side wall portion extends. A capping mechanism characterized by being non-uniform in the direction intersecting with. 2. The capping mechanism according to claim 1, wherein a distribution of the contact surface pressure is non-uniform depending on a cross-sectional shape of the contact portion in a direction intersecting with an extending direction of the side wall portion. The capping mechanism according to claim 1 or 2, wherein the shape of the abutting portion is formed asymmetrically between the inside and the outside of the side wall portion. The capping mechanism according to claim 3, wherein the asymmetric shape of the contact portion is formed such that the contact pressure on the outer side of the side wall portion is higher than that on the inner side. The capping mechanism according to claim 4, wherein the abutting portion is formed as a slope inclined in a direction in which an outer side is closer to the discharge port surface. The capping mechanism according to claim 2 or 3, wherein a rib composed of at least one protrusion extending in an annular shape along the corresponding contact portion is formed on the contact portion. The capping mechanism according to claim 6, wherein the rib is provided outside the contact portion. The said abutting part is provided with two or more of the said ribs, The outermost and innermost rib in it forms the shoulder part of the outer side and the inner side of the said abutting part. Capping mechanism. The capping mechanism according to claim 1, wherein the contact portion is made of at least two kinds of materials having different hardnesses. The region closer to the inside of the contact portion is made of a relatively soft rubber-like elastic material, and the region closer to the outside of the contact portion is made of a relatively hard rubber-like elastic material. 9. The capping mechanism according to 9. The capping mechanism according to any one of claims 1 to 10, wherein the capping mechanism contacts the discharge port surface on the inside and outside of the contact portion. The capping mechanism according to claim 1, wherein the cap is connected to a negative pressure generating unit that sucks ink from an ejection port by setting the inside of the cap to a negative pressure. In an inkjet recording apparatus provided with a capping mechanism having a cap made of an elastic material that is in contact with an ejection port surface to cover an ejection port of a recording unit that ejects ink.
An ink jet recording apparatus, wherein the capping mechanism is the capping mechanism according to claim 1.

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