JP5186963B2 - Liquid container and image forming apparatus - Google Patents

Description

  The present invention relates to a liquid container and an image forming apparatus, and more particularly to a liquid container having an openable and closable atmosphere opening passage and an image forming apparatus including the same.

    As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a complex machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording method using a recording head for discharging ink droplets. . This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  In the present application, “image forming apparatus” means an apparatus that discharges droplets onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “To not only give an image having a meaning such as a character or a figure to a medium, but also to give an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). Also means. “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials and the like are also included.

In an image forming apparatus that includes such an apparatus for ejecting liquid droplets and forms an image, a sub-capacity liquid storage container that supplies a recording liquid to a recording head on a carriage (referred to as a head tank or a buffer tank). The main cartridge (main tank) with a large capacity is installed on the main body side of the printer, and the head tank is supplied with recording liquid (ink) from the main cartridge on the main body side. There is known an apparatus or an apparatus in which an ink cartridge which is a recording liquid storage container is mounted so as to be exchangeable together with the recording head.
JP 2000-043289 A JP 2002-086748 A JP 2005-138472 A JP 2007-210231 A

  By the way, in a general image forming apparatus using a sub tank, a supply tube for supplying ink from the main tank to the sub tank and a flexible film member serving as a damper for suppressing pressure fluctuation in the sub tank are provided. However, the air gradually permeates with long-term use, and eventually the air accumulates in the sub-tank. Also, the air enters the sub-tank slightly with the removal of the main tank, and this is supplied to the sub-tank along with the ink. As a result, air enters the sub tank.

  Here, for example, in Patent Document 3 or 4, a holder that is attached to a case (container body) and has an air opening hole that communicates with the air flow path of the container body through the air opening hole at the tip portion, and a holder A valve seat that communicates with the air opening hole and the air flow path, a ball that is a valve body that moves so as to abut against or separate from the valve seat, and a bias that a ball abuts against the valve seat And an atmospheric release mechanism having a pressing pin provided in the holder and having one end projecting outward from the air opening hole and the other end facing the ball. The sub-tank is described in which the air release mechanism is opened by being pressed by the air release pin that is operated in the above.

  However, when the valve seat is assembled in the above-described subtank configuration, the valve seat is compressed in the radial direction and the surface direction, so that the inner peripheral side is distorted if the center of the holder member and the valve seat is not perfectly aligned. The phenomenon occurs. When distortion occurs on the inner peripheral side of the valve seat, there is a problem that the contact of the ball becomes incomplete and the negative pressure in the tank is not maintained due to the occurrence of a leak, resulting in an ink ejection abnormality.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the occurrence of leakage by reducing the inner diameter distortion of the valve seat member.

In order to solve the above problems, the liquid container according to the present invention is:
A communication path that communicates the inside and outside of the container body that contains the liquid;
A valve means having an annular valve seat member disposed in the communication passage and a valve body that is pressed and urged from the inside to seal the valve seat member;
A pressing member penetrating through the valve seat member of the valve means and movably arranged to press the valve body from the outside to open the valve, and
The pressing member has a first portion that has an outer diameter smaller than the inner diameter of the valve seat member and advances and retreats in the valve seat member, and a second portion that has an outer diameter substantially the same as the inner diameter of the valve seat member And formed,
The pressing member is configured so that the second portion can be fitted into the valve seat member.

  Here, the said pressing member can be set as the structure arrange | positioned in the state which the said 2nd part does not approach into the said valve seat member at the time of advance / retreat operation | movement. Moreover, it can be set as the structure by which the unevenness | corrugation is formed in the pressing surface of the member which presses down the side surface of the said valve seat member. Moreover, it can be set as the structure by which the projection part is formed in the internal peripheral surface of the member holding the outer peripheral surface of the said valve seat member.

  These liquid storage containers can be configured to store liquid supplied to a liquid discharge head that discharges droplets.

  The image forming apparatus according to the present invention includes the liquid container according to the present invention.

  According to the liquid container according to the present invention, the pressing member has a first portion that has an outer diameter smaller than the inner diameter of the valve seat member and advances and retracts in the valve seat member, and substantially the same as the inner diameter of the valve seat member. A second portion having an outer diameter is formed, and the pressing member is configured so that the second portion can be fitted into the valve seat member, so that the valve seat is compressed and mounted in the radial direction and the surface direction. Sometimes, the valve seat member can be mounted in a state in which the second portion of the pressing member is fitted in the valve seat member, and the distortion of the valve seat member is reduced, so that the valve body can be reliably sealed with the valve body. Leakage from the communication path is reduced.

  According to the image forming apparatus of the present invention, since the liquid storage container according to the present invention is provided, leakage of the liquid storage container is reduced, and stable image formation can be performed without causing defective ejection. .

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 will be described with reference to FIGS. FIG. 1 is an explanatory side view for explaining the overall configuration of the image forming apparatus, and FIG. 2 is an explanatory plan view of a main part of the apparatus.
This image forming apparatus is a serial type ink jet recording apparatus, and a carriage 33 is slidable in a main scanning direction by main and sub guide rods 31 and 32 which are guide members horizontally mounted on the left and right side plates 21A and 21B of the apparatus main body 1. It is held and moved and scanned in the direction indicated by the arrow (carriage main scanning direction) in FIG. 2 via a timing belt by a main scanning motor (not shown).

  The carriage 33 is provided with recording heads 34a and 34b composed of liquid ejection heads for ejecting ink droplets of yellow (Y), cyan (C), magenta (M), and black (K). The “recording head 34” is arranged in a sub-scanning direction orthogonal to the main scanning direction, and the ink droplet ejection direction is directed downward.

  Each of the recording heads 34 has two nozzle rows. One nozzle row of the recording head 34a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 34b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets.

  The carriage 33 is equipped with sub tanks 35a and 35b (referred to as “sub tanks 35” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 34. The sub tank 35 is replenished and supplied with ink of each color from the ink cartridges 10 y, 10 m, 10 c, and 10 k of each color that is detachably attached to the cartridge loading unit 4 via the supply tube 36 of each color by the supply pump unit 5. Is done.

  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. The transport belt 51 rotates in the belt transport direction of FIG. 2 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 spur 63 that is a paper discharge roller. And a paper discharge tray 3 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. 2, a maintenance / recovery mechanism 81 for maintaining and recovering the state of the nozzles of the recording head 34 is disposed in the non-printing area on one side of the carriage 33 in the scanning direction. The maintenance / recovery mechanism 81 includes cap members (hereinafter referred to as “caps”) 82a and 82b (hereinafter referred to as “caps 82” when not distinguished from each other) for capping the nozzle surfaces of the recording head 34, and nozzle surfaces. A wiper member (wiper blade) 83 for wiping the recording medium, an empty discharge receiver 84 for receiving liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid, and a carriage And a carriage lock 87 for locking 33. A waste liquid tank 100 for storing waste liquid generated by the maintenance recovery operation is mounted on the lower side of the head recovery mechanism 81 in a replaceable manner with respect to the apparatus main body.

  In addition, as shown in FIG. 2, 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 this image forming apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feed tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide 45, and includes the transport belt 51 and the counter. It is sandwiched between the rollers 46 and conveyed, and the leading end is guided by the conveying guide 37 and pressed against the conveying belt 51 by the leading end pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately repeated with respect to the charging roller 56, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 51 alternates, that is, in a sub-scanning direction that is a circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. 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.

  When performing the maintenance and recovery of the nozzles of the recording head 34, the nozzle 33 performs the suction from the nozzles by moving the carriage 33 to a position facing the maintenance and recovery mechanism 81 which is the home position and performing capping by the cap member 82. By performing a maintenance and recovery operation such as idle ejection for ejecting droplets that do not contribute to image formation, image formation by stable droplet ejection can be performed.

  Next, an example of a liquid container (subtank) according to the present invention applied to a subtank in the image forming apparatus will be described with reference to FIGS. 3 is an explanatory perspective view of the head portion, FIG. 4 is an explanatory side view thereof, and FIG. 5 is an exploded perspective explanatory view of a sub tank main body (container main body).

  The head portion includes a sub tank 35 and a filter unit interposed between the sub tank 35 and the recording head 34 for supplying different color inks to one recording head 34 and two nozzle rows of the one recording head 34, respectively. 101, and a flexible cable 102 (shown by adding “A” and “B” to the reference numeral) for transmitting a signal for driving the actuator means of the recording head 34 is drawn out from the recording head 34. ing.

  The sub tank 35 forms two ink containing portions 201 which are liquid containing portions on both sides of a container main body (tank main body) 202, and a flexible film-like member (possible (Flexible film-like member) 211 is attached and sealed by adhesion or welding, and the film-like member 211 is urged outwardly between the tank body 202 and the film-like member 211 inside the ink container 201. A spring (spring) 212 which is an elastic member for this purpose is disposed, and a negative pressure generating mechanism is configured by the film-like member 211 and the elastic member 212. Further, a negative pressure detection lever 213 that is displaced according to the displacement of the film-like member 211 is attached to the container body 202 so as to be able to swing.

  Further, an air release passage 203 for opening the ink containing portion 201 to the atmosphere is formed in the upper part of the tank main body 202, and an air release mechanism 204 for opening and closing the air release passage 203 is provided.

  In addition, an ink supply port portion 207 for supplying ink to the ink containing portion 201 is formed in the tank main body 202, and the tube 36 is connected by a connecting member 208. In addition, two detection electrodes 216 for detecting ink in the ink containing portion 201 are provided on the upper portion of the container main body 202.

  Here, on the bottom surface of the tank body 202, supply ports 217 for individually supplying ink from the ink storage portions 201A and 201B to the filter unit 101 are formed at the end portions of the ink storage portions 201, respectively. In order to arrange the mouth 217 in the center portion, the ink containing portion 201 is formed with a bulging portion 218 that swells in the other containing portion.

Next, the atmosphere release mechanism in the sub tank 35 will be described with reference to FIGS. 6 is an explanatory plan view of the air release mechanism portion, FIG. 7 is an enlarged view of the main part, and FIG. 8 is an explanatory perspective view of the main part.
The atmosphere release mechanism 204 integrally forms a hollow holder attachment portion 221 that forms an atmosphere release path 220 that communicates with the inside and outside of the container body 202 through the atmosphere communication path 203 laterally at the top of the container body 202. ing.

  A valve seat member (hereinafter referred to as “valve seat”) 223 is held between the holder attachment portion 221 and the holder 222 attached to the holder attachment portion 221, and is opened to the atmosphere opening path 220. A ball 224 as a valve body that is pressed and urged by a coil spring 225 that is a pressurizing unit in a direction to be pressed against the valve seat 223 is housed therein. These valve seats 223, balls 224, and coil springs 225 constitute valve means capable of opening and closing the atmosphere release path 220. Note that seal members 226 are interposed on both surfaces of the valve seat 223. In FIG. 6, the atmosphere release mechanism 204A shows a state where the atmosphere release path 220 is opened, and the atmosphere release mechanism 204B shows a state where the atmosphere release path 220B is closed.

  Here, the holder 222 as a holding member is mounted on the holder mounting portion 221 and holds the mounting portion 231 that holds the outer periphery of the valve seat 223 and the release member 241 that is a pressing member, and forms an outlet of the air release path 220. The holder mounting portion 221 is mounted by fitting a notch 222a formed on the outer periphery of the mounting portion 231 with a protrusion 221a provided on the holder mounting portion 221 (see FIG. 3). In addition, a reinforcing rib 231a is formed on the outer peripheral surface of the mounting portion 231 of the holder 222 in order to compensate for a decrease in strength due to the provision of the notch portion 222a.

  The holding portion 232 of the holder 222 presses the ball 224 against the urging force of the coil spring 225 to open the valve means, and the outlet portion formed by the holding portion 232 is formed in the atmosphere opening path 220. An opening member 241 that is a pressing member for opening to the atmosphere is mounted so as to be able to advance and retreat.

  The opening member 241 is pressed by a pressing portion 242 that is inserted into the holding portion 232 of the holder 222 and presses the ball 224 constituting the valve means, and an air release pin member 251 that is a member that presses the opening member 241 from the outside. And a cover portion 244 that covers the opening (hollow portion) of the holding portion 232 that becomes the outlet portion of the atmosphere opening passage 220. As shown in FIG. 8, the pressing portion 242 of the opening member 241 has a side surface 242a cut away to ensure a flow path for opening to the atmosphere with the inner peripheral surface of the holder 223.

  Next, the opening member 241 and the holder 222 are fitted together with a convex portion 233 formed on the outer peripheral surface of the holding portion 232 of the holder 222 and a concave portion 245 formed on the cover portion 244 of the opening member 241. The opening member 231 is mounted so as to be movable in a direction in which the ball 225 constituting the valve means is pressed and not detached from the holding portion 232.

  In this configuration, as shown in FIG. 7A, the cover 244 of the opening member 241 is attached to the holder 222 by inserting the pressing portion 242 of the opening member 241 into the holding portion 232 of the holder 222 and pushing it in the direction indicated by the arrow. As shown in FIG. 5B, the convex portion 233 of the holder 222 is fitted into the concave portion 245 of the opening member 241, and the opening member 241 is pushed by the urging force of the coil spring 225. However, it is prevented from being removed from the holder 222, and it can move in the direction of the arrow by the length of the recess 245 so that the ball 224, which is a valve body, can be pushed in and released.

  Next, the occurrence of distortion when the valve seat 223 is assembled in the atmosphere release mechanism 204 of the sub tank 35 will be described with reference to FIGS. 16 and 17. 16 is a schematic explanatory view of the collapse in the radial direction due to the center shift of the valve seat, and FIG. 17 is a schematic explanatory view showing the state of the collapse in the thickness direction due to the center shift of the valve seat.

  As described above, the valve seat 223 is fitted into the holder 222. However, the inner diameter of the holder 222 and the outer diameter of the valve seat 223 should be slightly larger when the assembly is prioritized. Is preferred. In this case, when the valve seat 223 is crushed in the radial direction, a gap 301 is generated due to the difference in the diameters, so that the valve seat 223 is not crushed uniformly with respect to the inner diameter.

  That is, when the valve seat 223 is in contact with the holder 222 at a part of the outer periphery, when the holder 222 is attached to the holder attaching portion 221, the valve seat 223 is crushed in the surface direction by the holder attaching portion 221, but the holder 222 The outer surface of the surface 223a in contact with the inner peripheral surface is restricted from being crushed in the outward direction, and the inner peripheral surface side is crushed in the inner direction (arrow A direction). On the other hand, the surface 223b not in contact with the inner peripheral surface of the holder 221 is crushed in the outer direction (arrow B direction) and the inner direction (arrow C direction). Thereby, the distortion of the inner peripheral side of the valve seat 223 occurs.

  As shown in FIG. 17, the position of the inner diameter of the valve seat 223 tends to follow the position of the ball 224, so that the inner periphery of the valve seat 223 is inclined even if the inner periphery is inclined.

  Therefore, in this embodiment, as shown in FIG. 8, the pressing portion 242 of the opening member 241 as a pressing member has an outer diameter D2 smaller than the inner diameter D1 of the valve seat 223, and the inside of the valve seat 223 is inside. A first portion 242a that advances and retreats and a second portion 242b that has an outer diameter D3 that is substantially the same as the inner diameter D1 of the valve seat 223 are formed, and the second portion 242b of the pressing portion 242 of the opening member 241 is further inserted into the valve seat 223. It is arranged in a state where it can be pushed into a position where it can be fitted.

  Specifically, in the normal operation of the apparatus, when the opening member 241 is pressed by the pressing pin member 251, it moves only from the position E to the position F in FIG. It is provided so that only a gap is made. Therefore, the second member 242b of the pressing portion 242 of the opening member 241 is fitted into the valve seat 223 by inserting the opening member 241 all the way into the holder 222 so that there is no gap portion of the distance L.

  Therefore, when the holder 222 fitted with the valve seat 223 is attached to the holder attaching portion 221, the opening member 241 is inserted into the holder 222 as far as the gap portion of the distance L disappears as shown in FIG. The second portion 242 b of the pressing portion 242 of the member 241 is brought into a state of being fitted in the valve seat 223.

  As a result, since the inner peripheral side of the valve seat 223 is fitted into the second portion 242b of the pressing portion 242 and regulated, when the holder mounting portion 221 is crushed, the collapse of the valve seat 223 tends to be uniform. Circumferential distortion is reduced.

  Then, after attaching the holder 222 to the holder attaching portion 221, the second portion 242b of the pressing portion 242 of the opening member 241 is extracted from the valve seat 223. Accordingly, as described above, during normal operation, only the first portion 242a of the pressing portion 242 of the opening member 241 penetrates the valve seat 223 and presses the ball 224, so that the pressing portion 242 and the valve seat 223 interfere with each other. As a result, malfunction does not occur.

  The outer diameter D3 of the second portion 242b of the pressing portion 242 of the opening member 241 is within ± 0.1 mm with respect to the inner diameter D1 of the valve seat 223, so that the second portion of the pressing portion 242 can be smoothly moved from the valve seat 223. The portion 242b can be removed. As shown in FIGS. 6 and 8, in the atmosphere opening mechanism 204 having the above configuration, the distance M between the outer peripheral side end surface of the opening member 241 and the end surface of the holder 222 needs to be not less than the distance L.

  Thus, the pressing member has a first part that has an outer diameter smaller than the inner diameter of the valve seat member and advances and retreats in the valve seat member, and a second part that has an outer diameter substantially the same as the inner diameter of the valve seat member. And the pressing member is configured such that the second portion can be fitted into the valve seat member. Therefore, when the valve seat is compressed and mounted in the radial direction and the surface direction, the second portion of the pressing member is formed. The valve seat member can be mounted with the two parts fitted in the valve seat member, the valve seat member is uniformly crushed, the distortion of the valve seat member is reduced, and the valve body is securely sealed. It can stop and the leak from a communicating path reduces.

  Moreover, in this embodiment, the surface (pressing surface) 222a with which the valve seat 223 of the holder 222 that presses the side surface of the valve seat 223 contacts is blasted to be a blasted surface (rough surface). The contact area of the holder 222 is reduced, the degree of freedom of movement of the valve seat 223 is improved, and the valve seat 223 is more uniformly crushed. Note that this portion is not related to the sealing property with the atmosphere, and may be an uneven surface other than the blast surface if there is a method for reducing the contact resistance.

  Further, as shown in FIG. 10, at least four protrusions (ribs) 222b are provided on the inner surface of a holder 222 that is a member that holds the outer peripheral surface of the valve seat 223, and the ribs 222b face each other in the diametrical direction. In addition, by adjusting the height of the rib 222b to 0.1 mm or less, the dimensional fitting of the outer diameter of the valve seat 223 and the inner diameter of the holder 222 is adjusted while reducing the positional deviation between the valve seat 223 and the holder 222. In addition to being easy, the ribs 222b face each other, so that centering is easy. Moreover, if the height of the rib 222b is 0.1 mm or less, the deformation change of the outer peripheral side of the valve seat 223 by the rib 222b does not affect the inner peripheral side, and the inner peripheral side distortion can also be suppressed.

  Further, in this embodiment, the inner diameter D4 of the holder 222 serving as a holding member that holds the pressing portion 242 of the opening / closing member 241 that is a pressing member so as to advance and retreat is formed larger than the inner diameter D1 of the valve seat 223. Therefore, in a state where the valve seat 223 is fitted into the holder 222, the inner peripheral surface of the valve seat 223 is disposed on the inner side of the inner peripheral surface of the holder 222.

  Therefore, as shown in FIG. 11, instead of the opening / closing member 241, a pin member 261 having the same outer diameter D1 as the inner diameter D1 of the valve seat 222 is used to attach the holder 222 into which the valve seat 223 is fitted to the holder mounting portion 221. When attaching to the pin seat 261, the pin member 261 is fitted into the valve seat 223.

  Thereby, since the inner peripheral side of the valve seat 223 is fitted into the pin member 261 and regulated, when the holder mounting portion 221 is crushed, the valve seat 223 is crushed uniformly, and the inner peripheral side is distorted. To reduce. Then, after assembling, the pin member 261 is pulled out and the opening member 241 is inserted.

  In this way, by using another pin member, the above-described limitations due to the distances L and M are eliminated, and the valve mechanism can be reduced in size. When the pin member is used in this way, it is not necessary to use the pressing member 242 having the first portion 242a and the second portion 242b as the opening member 241. As in the other embodiments described below, The pressing part 242 having a constant outer diameter can be used.

  As described above, the holding member that holds the outer peripheral surface of the pressing member so as to be movable forward and backward is provided, and the inner diameter of the holding member that holds the pressing member is larger than the inner diameter of the valve seat member. When mounting with compression in the surface direction, instead of the pressing member, it can be mounted with a pin member having an outer diameter substantially the same as the inner diameter of the valve seat member inserted, reducing distortion of the valve seat member And it can seal reliably with a valve body, and the leak from a communicating path reduces.

Next, an atmosphere release mechanism according to another embodiment of the present invention will be described with reference to FIGS. 12 is a cross-sectional explanatory view of the air release mechanism, FIG. 13 is a cross-sectional explanatory view of an example of the valve seat of the air release mechanism, and FIG. 14 is a cross-sectional description of another example of the valve seat. FIG.
In this air release mechanism 204, an opening member 241 having a constant outer diameter of the pressing portion 242 is used. Further, the inner diameter of the valve seat 223 is larger than the inner diameter of the holder 222.

  Then, as shown in FIG. 13 or FIG. 14, the valve seat 223 is made of a material having a different hardness, and the hardness of the portion in contact with the ball 224 serving as the sealing member remains as it is, and at least a portion of the hardness on the outer peripheral side. Is high.

  That is, the valve seat 223 shown in FIG. 13 has a high hardness portion 401 having a relatively high hardness on the outer peripheral side and a low hardness portion 402 having a relatively low hardness on the inner peripheral side with which the valve body 224 contacts. Yes.

  Further, the valve seat 223 shown in FIG. 14 has a high hardness portion 401 having a relatively high hardness on the side opposite to the side on which the valve body 224 abuts in the central axis direction, and a hardness relatively on the side on which the valve body 224 abuts. The low hardness portion 402 is formed, and the high hardness portion 401 is thicker than the low hardness portion 402.

  When the valve seat 223 configured as described above is inserted into the holder 222 and fixed by pressure contact with the holder mounting portion 221, if there is a high hardness portion 401 with high hardness on the outer peripheral side, the repulsive force with the holder 222 The valve seat 223 itself tends to settle at the center of the holder 222. Further, since the hardness of the contact portion with the ball 224 serving as the sealing member remains as it is (low hardness portion 402), there is little difference in the contact state between the whole and the low hardness portion.

  The valve seat 223 is preferably made of a material having a low water vapor transmission rate that prevents ink from evaporating and sticking from the nozzles and preventing air from flowing from the atmosphere to the nozzles. Rubber is butyl rubber, plastic is polyethylene, polypropylene, and fluororesin. preferable. However, if there are required performance or other means for preventing and recovering air intrusion, etc., as rubber, fluorine rubber, nitrile rubber, styrene butadiene rubber, silicone rubber, fluorosilicon rubber, ethylene propylene rubber, acrylic rubber, chloroprene rubber, etc. Can also be selected.

  Thus, since the valve seat member is configured such that the hardness of at least a part of the outer peripheral portion held by the holding member is higher than the hardness of the portion where the valve body abuts, the valve seat member is held. When fitted into the member, the outer periphery of the valve seat member follows the holding member, distortion of the valve seat member is reduced, and the valve body can be reliably sealed with a leak, and leakage from the communication path is reduced.

  The molding method of the valve seat 223 formed with different hardness as in these configurations will be described. Generally, there are a compression molding (compression molding) method and an injection molding (injection molding) method as the valve seat molding method.

In the compression molding method, the material mixed in the mold cavities (air gaps) is placed in the mold divided into the upper and lower molds, the upper and lower molds are put together and sandwiched between hot plates, and vulcanized while pressing. It is a method to do.
An injection molding method is a method of injecting a material blended into the space of a molded product in a state where the upper and lower molds are combined.

  In order to mold the valve seat 223 having different hardness in the radial direction shown in FIG. 13, the injection molding method is advantageous. A plurality of injection ports are provided and injected so as to be substantially the target with respect to the center of the valve seat hole. As an example, FIG. 15 shows the relationship between the injection port and the valve seat. In this example, the high hardness material 401a is injected from the injection port 411 and the low hardness material 402a is injected from the injection port 412 and molded. Although it is in the form of a sheet having projections at the time of molding, an annular final shape can be obtained by performing die cutting at C1 and C2 shown in the figure.

  Moreover, the compression molding method is advantageous for the valve seat 223 having different hardness in the direction of the central axis shown in FIG. Although the target is almost the center of the valve seat hole, the hardness of the material is different from the hole direction. When the thickness of the materials with different hardness is uniform, it is easiest to mold, but it is also possible to change the thickness depending on how to put the material blended in the cavity (air gap) or split the upper and lower molds . In the case of the compression molding method as well, the sheet is formed in a convex shape as in the injection molding method at the time of molding, but an annular final shape can be obtained by performing die cutting.

  The image forming apparatus according to the present invention is not limited to a printer having a single function configuration, and may be an image forming apparatus having a combined function such as printer / facsimile / copying. It may be applied to an image forming apparatus.

1 is a schematic side view illustrating an overall configuration of an ink jet recording apparatus as an image forming apparatus according to a first embodiment of the present invention. It is principal part plane explanatory drawing of the mechanism part. It is a perspective explanatory view of a head part for explanation of an example of a liquid container (sub tank) concerning the present invention. It is side surface explanatory drawing of a subtank main body (container main body) similarly. It is an exploded perspective view similarly. It is a plane cross-section explanatory drawing of the air release mechanism of the container. It is a principal part perspective explanatory drawing similarly. It is a principal part expansion explanatory drawing similarly. It is explanatory drawing with which it uses for the description at the time of valve seat assembly | attachment similarly. It is side surface explanatory drawing which similarly shows the other example of a holder. It is explanatory drawing with which it uses for the description at the time of valve seat assembly | attachment similarly when using a pin member. It is a plane cross-sectional explanatory drawing of the air release mechanism part in other embodiment of this invention. It is sectional explanatory drawing explaining an example of the valve seat of the same air release mechanism. It is a section explanatory view explaining other examples of a valve seat similarly. It is explanatory drawing with which it uses for description of shaping | molding of the valve seat of FIG. It is sectional explanatory drawing with which it uses for description of distortion of a valve seat. It is a section explanatory view similarly used for explanation of distortion of a valve seat.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Apparatus main body 2 ... Paper feed tray 3 ... Paper discharge tray 33 ... Carriage 34 ... Recording head 35 ... Sub tank 51 ... Conveyor belt 201 ... Ink storage part 202 ... Container main body 203 ... Air release path 204 ... Air release mechanism 220 ... Air Open path 221 ... Holder mounting portion 222 ... Holder 223 ... Valve seat (valve seat member)
224 ... Ball (valve)
241 ... Opening member 242 ... Pressing part 242a ... First part 242b ... Second part 401 ... High hardness part 402 ... Low hardness part

Claims (6)

A communication path that communicates the inside and outside of the container body that contains the liquid;
A valve means having an annular valve seat member disposed in the communication passage and a valve body that is pressed and urged from the inside to seal the valve seat member;
A pressing member penetrating through the valve seat member of the valve means and movably arranged to press the valve body from the outside to open the valve, and
The pressing member has a first portion that has an outer diameter smaller than the inner diameter of the valve seat member and advances and retreats in the valve seat member, and a second portion that has an outer diameter substantially the same as the inner diameter of the valve seat member. And formed,
The liquid container according to claim 1, wherein the pressing member is provided so that the second portion can be fitted into the valve seat member.   The liquid container according to claim 1, wherein the pressing member is arranged in a state in which the second portion does not enter the valve seat member during an advance / retreat operation.   3. The liquid container according to claim 1, wherein unevenness is formed on a pressing surface of a member that presses a side surface of the valve seat member. 4.   4. The liquid container according to claim 1, wherein a protrusion is formed on an inner peripheral surface of a member that holds an outer peripheral surface of the valve seat member. In the liquid container according to any one of claims 1 to 4, the liquid container, characterized by containing the liquid to be supplied to the liquid ejection head for ejecting liquid droplets. An image forming apparatus comprising the liquid container according to claim 5 .

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