JP4302499B2 - Pressure control mechanism and ink jet recording apparatus - Google Patents

Description

  The present invention is a pressure control mechanism in which a pressure control valve for opening to the atmosphere is composed of a packing and a contact / separation member (corresponding to an “opening / closing member”), and the atmospheric pressure in the sub tank is controlled by opening / closing the pressure control valve. And an ink jet recording apparatus.

  A conventional inkjet recording apparatus includes an ink tank for storing ink, and the ink tank includes a bubble generator (corresponding to an “orifice”) having a tubular boss and a sphere provided in the boss. The ink itself directly enters the orifice portion by capillary force to form a liquid seal (see, for example, Patent Document 1). Here, when the negative pressure (corresponding to “back pressure”) becomes high, the liquid seal is broken and air enters from the outside. After that, when the negative pressure becomes moderate, ink enters again to form a liquid seal. Become.

In addition, a sub-tank that stores ink supplied from an ink cartridge (corresponding to a “detachable ink tank”) and a drive unit for controlling the pressure of the sub-tank are provided. The sub-tank includes an air release port and a negative pressure lever. The drive unit has an air release pin, a negative pressure pin that pressurizes the negative pressure lever, a lever that pressurizes these pins, and a drive mechanism for the lever, and drives the lever of the drive unit to release the air release pin. Some perform a pressurizing operation and an opening operation on the negative pressure pin (see, for example, Patent Document 2). Here, a sub tank is provided separately from the ink cartridge to be replaced by the user, and this is used as an auxiliary tank, thereby avoiding an increase in the size of the carriage and improving the recording speed.
Japanese Patent Laid-Open No. 06-210866 (lower right of page 3 to middle right of page 4, FIG. 3 etc.) JP 2003-231275 A (5th page, lower left to middle right, FIG. 1 etc.)

  However, in the conventional ink jet recording apparatus described in Patent Document 1, since the ink itself is used as a sealant, the colorant contained in the ink adheres to the seal portion and the orifice passage is blocked. Therefore, negative pressure control may be difficult. In the conventional ink jet recording apparatus as described in Patent Document 2, the negative pressure in the sub tank is mechanically adjusted by a drive unit provided on the main body side. There is no description or suggestion about improvement in sealing performance when the control valve is composed of a packing and an opening / closing member (corresponding to a “contact / separation member”).

  The present invention has been made to solve the conventional problems, and provides a pressure control mechanism and an ink jet recording apparatus that can improve sealing performance using a pressure control valve having a packing and a contact / separation member. With the goal.

According to a first aspect of the present invention, there is provided a pressure control mechanism comprising a ring-shaped silicon rubber packing attached to an opening of a tank for filling ink containing a high-boiling water-soluble organic solvent, and a contact with the silicon rubber packing. a moving assembly comprising a release configured to be capable metal balls, said that moving assembly is the air to the tank open or closed to the hole in the silicone rubber gasket and out, the said moving assembly pressurize It comprises a pressure control means for controlling the air pressure in the tank, and the contact portion of the silicone rubber gasket and said moving assembly is so the ink different from the liquid sealant adheres, the liquid sealing agent It has a configuration containing a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at 1 atm .

  Here, the “liquid sealant different from the predetermined liquid” includes “a liquid composed only of a specific component (not having a composition ratio)” in the predetermined liquid. That is, when the predetermined liquid is ink, “liquid obtained by removing colorant and other components from ink components” is also included. Further, a state in which a small amount of a predetermined liquid is adhering to the contact portion of the contact / separation member and the packing due to intentional or liquid scattering in the tank and mixed with the liquid sealant is also within the scope of the claims.

For reference, the pressure control mechanism of the present invention has a configuration in claim 1, wherein the liquid sealant is grease.

A pressure control mechanism according to a second aspect of the present invention is the pressure control mechanism according to the first aspect, wherein the liquid sealant contains a preservative and antifungal agent.

According to a third aspect of the present invention, there is provided the pressure control mechanism according to the first aspect, wherein when the radius of the metal sphere is d (cm), the liquid amount of the liquid sealant is 4πd ² × 0.1 (g). And 4πd ² × 0.0001 (g) or more.

The pressure control mechanism according to a fourth aspect of the present invention is the pressure control mechanism according to the first aspect, wherein the ink contains pigment-containing polymer fine particles as a colorant and a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at 1 atmosphere. The viscosity of the ink is 5 mPa · s or more.

Ink jet recording apparatus of the present invention according to claim 5, a head for ejecting an ink containing a high-boiling water-soluble organic solvent, a moving means for moving at the time of recording by mounting the head, disposed outside the moving means an ink tank detachable, which is, is supplied to the ink from the ink tank is mounted in said moving means, and the sub-tank for supplying the ink to said head, for controlling the air pressure within the sub tank A pressure control means, wherein the pressure control means comprises a ring-shaped silicon rubber packing attached to the opening of the sub-tank, and a contact / separation comprising a metal ball configured to be able to contact and separate from the silicon rubber packing. and the member, so that the moving assembly is the air in said sub-tank open or closed to the hole in the silicone rubber gasket and out, the contacting and spacing member pressed And a pressure control means for controlling the air pressure in the sub tank, wherein the contact portion of the moving assembly and the silicone rubber packing, as the ink is different from the liquid sealant adheres, the liquid sealant Has a constitution containing a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at 1 atm .

For reference, the ink jet recording apparatus of the present invention has a configuration in claim 5 in which the liquid sealant is grease.

An ink jet recording apparatus according to a sixth aspect of the present invention is the ink jet recording apparatus according to the fifth aspect , wherein the liquid sealant contains a preservative and antifungal agent.

An ink jet recording apparatus according to a seventh aspect of the present invention is the ink jet recording apparatus according to the fifth aspect , wherein when the radius of the metal sphere is d (cm), the liquid amount of the liquid sealant is 4πd ² × 0.1 (g). And 4πd ² × 0.0001 (g) or more.

An ink jet recording apparatus according to an eighth aspect of the present invention is the ink jet recording apparatus according to the fifth aspect , wherein the ink contains pigment-containing polymer fine particles as a colorant and a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at 1 atmosphere. The viscosity of the ink is 5 mPa · s or more.

  The present invention provides a pressure control valve having a packing and a contact / separation member by adhering a liquid sealant different from a predetermined liquid (corresponding to “ink”) to a contact portion between the contact / separation member and the packing. It is possible to provide a pressure control mechanism and an ink jet recording apparatus having an effect of improving the sealing performance.

  Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  An ink jet recording apparatus including a liquid supply apparatus including a sub tank having a pressure control mechanism according to the present invention will be described. FIG. 1 is a perspective explanatory view of the ink jet recording apparatus as viewed from the front side.

  The ink jet recording apparatus includes an apparatus main body 1, a paper feed tray 2 loaded in the apparatus main body 1 for loading paper as a recording medium, and a paper loaded in the apparatus main body 1 on which an image is recorded (formed). A discharge tray 3 for stocking, and further, on one end portion side of the front surface 4 of the apparatus main body 1, a cartridge loading portion 6 that protrudes forward from the front surface 4 and is lower than the upper surface 5. An operation unit 7 such as operation keys and a display is arranged on the upper surface of the cartridge loading unit 6. The cartridge loading unit 6 has a front cover 8 that can be opened and closed for attaching and detaching an ink cartridge 10 that is a liquid storage tank (main tank).

  Next, the mechanism part of the ink jet recording 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.

  A carriage 13 is slidably held in the main scanning direction by guide rods 11 and stays 12 which are horizontally mounted on left and right side plates (not shown), and moved and scanned in the direction of the arrow in FIG. 3 by a main scanning motor (not shown). To do.

  A recording head 14 composed of an ink jet head for ejecting ink droplets is arranged on the carriage 13 in such a manner that a plurality of nozzles are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  Here, for example, as shown in FIG. 4, the recording head 14 has a nozzle row 14yn composed of a large number of nozzles N that eject yellow (Y) ink droplets and a large number of magenta (M) ink droplets. A droplet discharge head 14a having a nozzle row 14mn made up of nozzles N, a nozzle row 14cn made up of a number of nozzles N that discharge cyan (C) ink droplets, and a number of nozzles that discharge black (Bk) ink droplets And a head 14b having a nozzle row 14kn made of N. Further, as shown in FIG. 5, color (CMY) and black (K) may be separated.

  As an ink jet head constituting the recording head 14 (used in the generic meaning of a plurality of heads), a piezoelectric actuator such as a piezoelectric element and an electrothermal conversion element such as a heating resistor are used to cause a phase change due to liquid film boiling. Thermal actuators used, shape memory alloy actuators using metal phase changes due to temperature changes, electrostatic actuators using electrostatic force, etc. can be used as energy generating means for ejecting ink. A head using (piezoelectric element) as energy generating means is mounted.

  Further, the carriage 13 has a sub tank 15 which is a liquid container of each color for supplying each color ink to each nozzle row 14yn, 14mn, 14cn, 14kn of the recording head 14 (if each color is distinguished, the nozzle row The codes 15y, 15m, 15c, and 15k are used correspondingly). The sub-tank 15 uses the main tank (ink cartridge) 10 for each color described above via the ink supply tube 16 (in order to distinguish each color, the symbols 10y, 10m, 10c, and 10k are used corresponding to the nozzle rows. ) Is replenished and supplied. Here, the main tank 10 stores ink of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) corresponding to each color, but the main tank 10 stores black ink. The tank 10k has a larger ink storage capacity than the main tanks 10y, 10m, and 10c that store other color inks.

  On the other hand, as a paper feeding unit for feeding the paper 22 stacked on the paper stacking unit (pressure plate) 21 of the paper feed tray 3, a half-moon roller (feeding) that separates and feeds the paper 22 from the paper stacking unit 21 one by one. A separation pad 24 made of a material having a large friction coefficient is provided opposite to the paper roller 23 and the paper feed roller 23, and the separation pad 24 is urged toward the paper feed roller 23 side.

  As a transport unit for transporting the paper 22 fed from the paper feed unit on the lower side of the recording head 14, a transport belt 31 for transporting the paper 22 by electrostatic adsorption, and a paper feed unit The counter roller 32 for transporting the paper 22 fed through the guide 25 while sandwiching it between the transport belt 31 and the paper 22 fed substantially vertically upward are turned approximately 90 ° and copied onto the transport belt 31. A conveying guide 33 for adjusting the pressure and a tip pressing roller 35 urged toward the conveying belt 31 by a pressing member 34. In addition, a charging roller 36 that is a charging unit for charging the surface of the transport belt 31 is provided.

  Here, the conveyance belt 31 is an endless belt, and is configured to be looped around the conveyance roller 37 and the tension roller 38 in the belt conveyance direction of FIG. The charging roller 36 is disposed so as to contact the surface layer of the conveyor belt 31 and rotate following the rotation of the conveyor belt 31, and applies 2.5 N to both ends of the shaft as a pressing force.

  In addition, a guide member 41 is disposed on the back side of the conveyance belt 31 so as to correspond to a printing area by the recording head 14. The upper surface of the guide member 41 protrudes toward the recording head 14 from the tangent line of the two rollers (the conveyance roller 37 and the tension roller 38) that support the conveyance belt 31. As a result, the conveyance belt 31 is pushed up and guided by the upper surface of the guide member 41 in the printing region, so that highly accurate flatness is maintained.

  Further, a plurality of grooves are formed in the main scanning direction, that is, in a direction orthogonal to the transport direction, on the surface side of the guide member 41 that contacts the back surface of the transport belt 31 to reduce the contact area with the transport belt 31. The conveying belt 31 can be moved along the surface of the guide member 41 smoothly.

  Further, as a paper discharge unit for discharging the paper 22 recorded by the recording head 14, a separation claw 51 for separating the paper 22 from the conveyance belt 31, a paper discharge roller 52, and a paper discharge roller 53 are provided. The paper discharge tray 3 is provided below the paper discharge roller 52. Here, the height from between the paper discharge roller 52 and the paper discharge roller 53 to the paper discharge tray 3 is increased to some extent in order to increase the amount that can be stored in the paper discharge tray 3.

  A double-sided paper feeding unit 61 is detachably mounted on the back surface of the apparatus body 1. The double-sided paper feeding unit 61 takes in the paper 22 returned by the reverse rotation of the transport belt 31, reverses it, and feeds it again between the counter roller 32 and the transport belt 11. A manual paper feed unit 62 is provided on the upper surface of the double-sided paper feed unit 61.

  Further, as shown in FIG. 3, in the non-printing area on one side (or both sides) of the carriage 13 in the scanning direction, a maintenance / recovery mechanism (hereinafter referred to as “recovery / recovery mechanism”) for maintaining and recovering the nozzle state of the recording head 14. "Subsystem") 71 is arranged. The subsystem 71 includes cap members 72A and 72B for capping the nozzle surfaces of the recording heads 14a and 14b, a wiper blade 73 for wiping the nozzle surfaces, and the like.

  In the ink jet recording apparatus configured as described above, the paper 22 is separated and fed from the paper feed tray 2 one by one, and the paper 22 fed substantially vertically upward is guided by the guide 25, and the conveyance belt 31 and the counter roller 32, and the tip is guided by the transport guide 33 and pressed against the transport belt 31 by the tip pressure roller 35, and the transport direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately repeated from the high voltage power source to the charging roller 36 by a control circuit (not shown), that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 31 is alternating, that is, In the sub-scanning direction, which is the circumferential direction, plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 22 is fed onto the conveyance belt 31 that is alternately charged with plus and minus, the sheet 22 is electrostatically attracted to the conveyance belt 31, and the sheet 22 is moved in the sub scanning direction by the circular movement of the conveyance belt 31. Be transported.

  Therefore, by driving the recording head 14 according to the image signal while moving the carriage 13, ink droplets are ejected onto the stopped paper 22 to record one line, and after the paper 22 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 22 has reached the recording area, the recording operation is finished and the paper 22 is discharged onto the paper discharge tray 3.

  During printing (recording) standby, the carriage 13 is moved to the subsystem 71 side, and the recording heads 14a and 14b are capped by the caps 72A and 72B. In addition, a recovery operation is performed to discharge ink that is not related to recording before the start of recording or during recording, thereby maintaining stable ejection performance.

  Next, details of the ink supply device, which is a liquid supply device in the recording apparatus, will be described with reference to FIGS. 6 is an exploded perspective view of a portion related to the ink supply device, FIG. 7 is an exploded perspective view of the sub tank, FIG. 8 is a schematic side view of the sub tank, and FIG. 9 is a line AA in FIG. FIG.

  As described above, the ink supply device is mounted on the carriage 13 and supplies a sub tank 15 which is a liquid container for supplying ink to each recording head 14 (14a, 14b), and the sub tank 15 is supplied with ink via a supply tube 16. And a main tank (ink cartridge) 10 for supply and replenishment.

  One sub tank 15 is a flexible film-like member that seals an opening (one surface of the sub tank 15) of the ink storage unit 100 to a container main body (case main body) 101 that forms the ink storage unit 100 that stores ink. (Flexible film-like member) 102 is attached by bonding or welding, and further, the film-like member 102 is biased outwardly between the case main body 101 and the film-like member 102 inside the ink containing portion 100. A spring (spring) 103 which is an elastic member is provided.

  Here, the film-like member 102 may have a single-layer structure, but as shown in FIG. 10A, a two-layer structure in which different types of first layer 102a and second layer 102b are laminated, for example, polyethylene and nylon. It is configured such that a film-like member is laminated, or as shown in FIG. 5B, a silica vapor deposition layer 102c is formed on the first layer 102a.

  By configuring the film-like member 102 to have two or more different types of layers, it is possible to improve the liquid resistance against the ink to be stored. In this case, by adopting a laminated structure of polyethylene and nylon, it is possible to reliably ensure liquid resistance against ink. Moreover, the liquid resistance with respect to the ink accommodated can also be improved by including a silica vapor deposition layer in the film-like member 102.

  The thickness of the film-like member 102 is preferably 10 to 100 μm. If the thickness is less than 10 μm, damage due to deterioration with time is likely to occur, and if it exceeds 100 μm, flexibility may be reduced and it may be difficult to efficiently generate negative pressure.

  Furthermore, a bulging portion 102a having a convex shape corresponding to the spring 103 is formed on the film-like member 102, and a reinforcing member 104 is attached to the outer surface thereof. In this manner, by providing the flexible film-like member 102 with the convex portion, the elastic member (here, the spring) 103 can be stably held. In this case, the flexible film-like member 102 can be easily formed with a convex portion by forming a sheet-like film member into a convex shape.

  Further, the case 101 is provided with an ink introduction path portion 111 for replenishing ink in the ink containing portion 100, and a connecting means for connecting the ink introduction path portion 111 and the supply tube 16 connected to the ink cartridge 10. 112 can be detachably mounted. A liquid feed pump as described later is provided between the ink cartridge 10 and the sub tank 15 in order to pressure-feed ink from the ink cartridge 10 to the sub tank 15.

  Further, a connecting member 113 for supplying ink from the ink storage unit 100 to the recording head 14 is attached to the lower part of the case 101, and an ink supply path 114 of the recording head 14 is formed in the connecting member 113. A filter 115 is interposed between the two.

  An air flow path 121 is formed in the upper part of the case 101 for taking out air from the ink containing portion 100. The air flow path 121 includes an inlet flow path portion 122 having an opening facing the ink containing portion 100 and a flow path portion (referred to as an “orthogonal flow path portion”) 123 following the inlet flow path portion 122. An accumulation portion 126 is continuously formed in a portion that communicates with the atmosphere opening hole 131 provided in the case 101 on the downstream side, and that is further below the atmosphere opening hole 131 in use.

  The atmosphere release hole 131 is provided with an atmosphere release valve mechanism 132 which is an atmosphere release means for switching between the sealed state and the atmosphere release state in the sub tank 15. This air release valve mechanism 132 has a valve seat (corresponding to a ring-shaped packing) 134 in the holder 133, a ball (corresponding to a contact / separation member) 135 as a valve body, and urging the ball 135 toward the valve seat 134. The spring 136 is housed and configured.

  The operation of the storage unit 126 will be described. When the apparatus main body is tilted or shaken, there is a high possibility that ink will enter the air flow path 121. Therefore, the ink that has entered from the air flow path 121 can be accumulated in the accumulating unit 126, and even if the ink is dropped during transportation, for example, the ink enters the atmosphere opening port 131 and the atmosphere opening valve mechanism 132 that opens and closes the ink. Prevents the atmosphere release valve mechanism 132 from malfunctioning due to intrusion and hardening.

  In addition, two detection electrodes 141 and 142 for detecting that the amount of ink in the sub tank 15 is equal to or less than a predetermined amount (this state is “no ink”) are attached to the upper portion of the case 101. ing. The absence of ink can be detected by changing the conduction state between the detection electrodes 141 and 142 in a state where both the detection electrodes 141 and 142 are immersed in ink and in a state where at least one of the detection electrodes 141 and 142 is not immersed in ink. .

  Further, as shown in FIGS. 6 and 7, an atmosphere release pin 153 for pressing the contact / separation member 135 of the atmosphere release valve mechanism 132 of the sub tank 15 against the spring 136 to release the atmosphere is provided so as to be able to advance and retract. is doing. A drive unit 162 including a lever 161 for operating the atmosphere release pin 153 is disposed on the apparatus main body side.

  Here, in order to arrange the two sub tanks 15 for one recording head 14, the back surfaces of the two sub tanks 15 are integrated as shown in FIG. In this case, the partition wall portion 100a between the two ink storage portions 100 may be shared.

  In the ink supply device configured in this way, the atmosphere release pin 153 is operated by the drive unit 162 to open the atmosphere release valve mechanism 132 of the sub tank 15, thereby opening the inside of the sub tank 15 to the atmosphere.

  Then, the ink is supplied from the ink cartridge 10 to the sub tank 15 by the liquid supply mechanism and supplied. At this time, the air in the sub tank 15 is exhausted through the atmosphere release valve mechanism 132.

  Thereafter, the atmosphere release valve mechanism 132 is closed to close the sub tank 15 from the atmosphere release, and the ink in the sub tank 15 is sucked from the nozzles with the recording head 14 capped by the cap 72A of the subsystem 71 ( By performing the head suction), since the urging force of the spring 103 is applied to the flexible film-like member 102, a negative pressure is generated in the sub tank 15.

  Next, the configuration of the subsystem 71 will be described with reference to FIG. 11 and FIG. 11 is an explanatory plan view of the system, and FIG. 12 is a schematic schematic configuration diagram.

  In the frame 211, two cap holders 212A and 212B, an idle discharge receptacle 213, a wiper blade 73 which is a wiping member including an elastic body as a cleaning means, and a carriage lock 215 are held so as to be able to move up and down. Yes.

  Cap holders 212A and 212B (hereinafter collectively referred to as “cap holder 212”) include caps 72A and 72B (hereinafter referred to as “cap 72”) for capping the nozzle surfaces of the recording heads 14a and 14b, respectively. Holding.

  Here, a tube pump (suction pump) 220 as a suction means is connected to the cap 72A held by the cap holder 212A closest to the printing area via the tube 219, and the tube pump 220 is connected to the other cap 72B. Not done. That is, only the cap 72A is a recovery and moisture retention cap, and the other cap 72B is a simple moisture retention cap. Therefore, when the recovery operation of the recording head 14 or the ink supply operation to the sub tank 15 is performed, the head 14 is selectively moved to a position where it can be capped by the cap 72A.

  A cam shaft 221 is rotatably disposed below the cap holders 212A and 212B. The cam shaft 221 includes cap cams 222A and 222B for moving the cap holders 212A and 212B up and down, and a wiper blade 73. A wiper cam 224 for raising and lowering the carriage and a carriage lock cam 225 for raising and lowering the carriage lock 215 via the carriage lock arm 217 are provided.

  Further, a wiper cleaner 218 for cleaning the wiper blade 73 can be swung in the direction indicated by an arrow on the print area side of the wiper blade 73 and is urged in a direction away from the wiper blade 73 by a spring (not shown). The camshaft 221 is provided with a wiper cleaner cam 228 for swinging the wiper cleaner 218.

  Here, the cap 72 is moved up and down by the cap cams 222A and 222B. The wiper blade 73 is moved up and down by the wiper cam 224. When the wiper cleaner 218 is moved downward, the wiper cleaner 218 moves forward and descends while being sandwiched between the wiper cleaner 218 and the empty discharge receiver 213, so that the ink attached to the wiper blade 214 is empty. It is scraped off by the discharge receptacle 213.

  The carriage lock 215 is urged upward (in the lock direction) by a compression spring (not shown) and is moved up and down by the carriage lock arm 217.

  In order to rotationally drive the tube pump 220 and the cam shaft 221, the rotation of the motor 231 is meshed with the motor gear 232 provided on the motor shaft 231 a and the pump gear 233 provided on the pump shaft 220 a of the tube pump 220 is further engaged. An intermediate gear 234 with a one-way clutch 237 is engaged with an intermediate gear 234 integrated with the intermediate gear 233, and the intermediate gear 238 coaxial with the intermediate gear 236 is fixed to the camshaft 221 via the intermediate gear 239. The cam gear 240 is engaged.

  The cam shaft 221 is provided with a home position sensor cam 241 for detecting the home position. When the cap 72 comes to the lowest end by a home position sensor (not shown) provided in the subsystem 71, a home position lever is provided. (Not shown) is activated, and the sensor is opened to detect the home position of the motor 231 (other than the pump 220). When the power is turned on, the position moves up and down regardless of the position of the cap 72 (cap holder 212), the position is not detected until the movement starts, and the position is determined after detecting the home position of the cap 72 (in the middle of rising). To the bottom end. Thereafter, the carriage moves left and right, returns to the cap position after position detection, and the recording head 14 is capped.

  In this subsystem 71, when the motor 231 rotates forward, the motor gear 232, the intermediate gear 233, the pump gear 234, the intermediate gears 235 and 236 rotate, and the shaft 220a of the tube pump 220 rotates, whereby the tube pump 220 is Operates and sucks the inside of the recovery / moisturizing cap 72a. Since the other gears 238 and thereafter are blocked by the one-way clutch 237, they do not rotate (activate).

  Since the one-way clutch 237 is connected by the reverse rotation of the motor 231, the rotation of the motor 231 is transmitted to the cam gear 240 through the motor gear 232, the intermediate gear 233, the pump gear 234, the intermediate gears 235, 236, 238 and 239. The cam shaft 221 rotates. At this time, the tube pump 220 has a structure that does not rotate by the reverse rotation of the pump shaft 220a.

  Next, an outline of the control unit of the image forming apparatus will be described with reference to the block diagram of FIG.

  The control unit 280 includes a CPU 281 that controls the entire apparatus, a ROM 282 that stores programs executed by the CPU 281 and other fixed data, a RAM 283 that temporarily stores image data, and the like, while the apparatus is powered off. And a non-volatile memory (NVRAM) 284 for holding data, an image processing for performing various signal processing and rearrangement on image data, and an ASIC 285 for processing input / output signals for controlling the entire apparatus. Yes.

  The control unit 280 also includes an I / F 286 for transmitting and receiving data and signals to and from the host, a head drive control unit 287 and a head driver 288 for driving and controlling the recording head 14, and a main scanning motor 290. A main scanning motor driving unit 291 for driving the sub-scanning motor 292, a sub-scanning motor driving unit 293 for driving the sub-scanning motor 292, a subsystem driving unit 294 for driving the motor 231 of the subsystem 71, and the sub tank 15 A sub-tank drive unit 295 (included in the pressurization control means) for driving the drive unit 162 (included in the pressurization control means) for releasing the atmosphere, detection signals of the detection electrodes 141 and 142 of the subtank 15 and not shown An I / O 296 for inputting detection signals from various sensors is provided.

  The control unit 280 is connected to an operation panel 297 for inputting and displaying information necessary for the apparatus.

  The control unit 280 receives print data and the like from the host side such as an information processing device such as a personal computer, an image reading device such as an image scanner, and an imaging device such as a digital camera via the cable or the network by the I / F 286.

  The CPU 281 reads out and analyzes the print data in the reception buffer included in the I / F 286, performs necessary image processing, data rearrangement processing, and the like in the ASIC 285, and transfers the image data to the head drive control unit 287. To do. The generation of dot pattern data for image output may be performed by storing font data in the ROM 282, for example, or image data is developed into bitmap data by a host-side printer driver and transferred to this apparatus. You may do it.

  When the head drive control unit 287 receives image data (dot pattern data) corresponding to one line of the recording head 14, the dot pattern data for one line is serialized to the head driver 288 in synchronization with the clock signal. Data is transmitted, and a latch signal is transmitted to the head driver 288 at a predetermined timing.

  The head drive control unit 287 includes a ROM (which can also be configured by a ROM 282) storing pattern data of a drive waveform (drive signal), and a D / A converter for D / A conversion of drive waveform data read from the ROM. A drive waveform generation circuit including a waveform generation circuit including an A converter and an amplifier is included.

  The head driver 288 also includes a shift register that receives a clock signal from the head drive control unit 287 and serial data that is image data, and a latch circuit that latches the register value of the shift register using a latch signal from the head drive control unit 287. And a level conversion circuit (level shifter) that changes the output value of the latch circuit, an analog switch array (switch means) that is controlled to be turned on / off by the level shifter, and the like, and controls the on / off of the analog switch array. In this way, a required drive waveform included in the drive waveform is selectively applied to the actuator means of the recording head 14 to drive the head.

  Further, the CPU 280 takes in the detection signals of the detection electrodes 141 and 142 via the I / O 296 and detects whether or not the ink amount in the sub tank 15 is exhausted. Thereby, the liquid amount detection sensor is configured.

  The overview of the entire apparatus has been described above.

  In the apparatus described above, the atmospheric release valve is opened and closed by opening and closing between the packing 134 and the contact / separation member 135 of the atmospheric release valve mechanism 132 of FIGS. 7 and 14, and the pressure in the sub tank is adjusted. When opening, as shown in FIG. 6, as described above, the atmosphere is released by pushing the atmosphere release pin 153 with the lever 161 and releasing the packing 134 and the contact / separation member 135. When the lever is not pushed, the contact / separation member 135 is in close contact with the packing 134 by the spring 136 and the release valve portion is shut off. FIG. 14 is an enlarged view of this portion. Here, when the lever 161 is not pushed, the air release pin is returned by a spring attached to the release pin so that the release valve portion is blocked.

  As a problem of this pressure control valve, when foreign matter is mixed between the packing 134 and the contact / separation member 135, a long-term sealing property cannot be maintained. If the sealing performance is not maintained, air leaks into the sub tank through this pressure control valve (also referred to as the air release valve here), and the negative pressure in the sub tank cannot be controlled. End up. This patent aims to solve the problem.

  Furthermore, it demonstrates according to a figure.

  FIG. 8 is an overall view of the sub tank. Initially, after the atmosphere release valve mechanism 132 is opened (atmospheric pressure), ink is supplied to the sub-tank until the signal indicating that ink is present at the electrodes 141 and 142, then the atmosphere release valve is closed, and then The negative pressure is generated by sucking a predetermined amount of ink from the head. Long-term use may cause air to enter the sub-tank from outside and maintain negative pressure. Even in that case, the pressure control valve part for opening to the atmosphere is opened and the atmospheric pressure is set, and then ink is supplied until an ink signal is given by the electrode (at this time, excess air is discharged from the opening valve part) Thereafter, after the air release valve portion is shut off, a negative pressure recovery method for sucking a predetermined amount of ink to obtain a target negative pressure is performed. As a factor of external air mixing, the pressure control valve part for opening to the atmosphere itself may have poor sealing performance and may leak from there. In particular, if foreign matter is mixed between the packing and the contact / separation member, the sealability of this portion may not be maintained. After the initial negative pressure was created and the damper film in the sub-tank was recessed, air leakage was observed as the film swelled. As a result, one hair having a diameter of about 70 μm became the packing 134 (in the case of silicon rubber) and the contact / separation member 135 ( If the material is present between the balls), it will leak completely (atmospheric pressure) in about 10 minutes. Even if the fibrous foreign material has a diameter of about 10 μm, a leak occurs in two or three. However, when a liquid was allowed to adhere between the packing and the contacting / separating member, it was found that even if a foreign substance of one hair was adhered between the packing and the contacting / separating member, no air leak occurred for more than one month. Even if it is a liquid, water alone is almost ineffective, and a component that hardly evaporates is necessary. As the material, when the packing is organic, for example, a water-soluble organic solvent is preferable in order not to dissolve the packing. That is, a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at least 1 atm is preferable. Although the pressure control valve unit does not directly contact the ink in the sub tank, in order to prevent the evaporated component of the liquid sealant from mixing with the ink in the tank and affecting the jetting stability, there is no problem even if mixed with the ink. Preferred materials are high boiling water soluble organic solvents. In particular, it is preferable if it is the same as the high-boiling water-soluble organic solvent contained in the ink. Examples of high-boiling water-soluble organic solvents include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, and 2,3-butanediol. 1,4-butanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 1,2,4-butanetriol, 2,6-hexanetriol, trimethylolpropane, trimethylolethane, thiodiglycol and pentaerythritol. Particularly preferred are those having a high boiling point and being difficult to evaporate. In that respect, polyvinyl alcohols that are liquid at room temperature are also preferred.

  Moreover, since the pressure control valve part for open | release to air | atmosphere is exposed to external air, generation | occurrence | production of mold | fungi is also a concern. Although it is not always necessary depending on the leaving environment, it is preferable to add a preservative and fungicide. As the antiseptic / antifungal agent, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used in the present invention.

  It should be noted that it is difficult to apply a uniform thin coating to a packing or the like because of a high viscosity only with a high-boiling water-soluble organic solvent. Therefore, it is preferable to add water.

The coating amount is preferably 4πd ² × 0.1 (g) or less and 4πd ² × 0.0001 (g) or more when the size of the contacting / separating member is a radius d (cm). More preferably, the amount of the sealing agent liquid is 4πd ² × 0.01 (g) or less and 4πd ² × 0.001 (g) or more. In this case, the thickness of the coating solution near the contact / separation member and the packing contact portion is approximately 10 to 100 μm. This amount of coating is preferable for preventing air leaks caused by foreign matters such as hair. When the amount is too large, when the liquid flows from the pressure control valve portion or when the viscosity becomes high after evaporation, the openability of the valve at the time of opening tends to be slightly deteriorated. If the amount is too small, the anti-foreign matter leakage preventing effect does not continue for a long time. The above-mentioned “thickness of the coating solution” is a calculated value assuming that the coating solution is not in close contact, but in actuality, the packing and the contacting / separating member are in close contact with each other, so that the thickness is thinner.

  Examples will be described below.

[First embodiment]
In this embodiment, the first sealing liquid, the second sealing liquid, and the third sealing liquid are prepared as the sealing agent, and the packing (shown in FIG. 14) of the sub-tank (shown in FIG. 8) that is left in the same environment is prepared. 134) and a ball as the contact / separation member (corresponding to 135 in FIG. 14), different adhesion amounts were applied depending on the first application method or the second application method, and the sealing effect was compared.

  Here, the leaving environment is provided in a sub-tank (sub-tank unit) in a state where the valve part (packing, ball) coated with the sealing agent is sealed (intervention of air), and a damper film (corresponding to 102 in FIG. 10) is provided. It was set as normal temperature normal humidity in the recessed sealing state. When the air release valve portion leaks air, the damper film is swelled by the spring 103 so that the presence or absence of air leak can be visually determined.

  The effect was judged by observing the leak state from the degree of opening of the damper film after being left in the environment described above. Specifically, “○: No leakage of one foreign hair at room temperature and humidity for 1 day or more” “△: One hair of foreign hair completely leaked at room temperature and humidity for 30 minutes or more within 1 day” “×: Foreign material One hair was judged to be “leak completely at room temperature and humidity within 30 minutes”.

  The packing made of silicon rubber and having a height of “0.28 cm”, a diameter of “0.7 cm”, and an inner diameter of “0.3 cm”) was used. A ball (metal sphere) is used as the contact / separation member, and its diameter is “about 0.397 cm”.

  The first sealing liquid is “1,3-butanediol (22.50% by weight), glycerin (7.50% by weight), surfactant (polyoxyarlene alkyl ether <trade name Softanol EP7025>) Nippon Shokubai) (1.00 wt%), antiseptic / antifungal agent (trade name Proxel LV (Zeneca Co., Ltd.) (0.15 wt%), organic pH adjuster (1.00 wt%, adjusted to pH 8 (seal) Even if there is no pH adjuster in the agent, it is effective)), water (residue)). The main of these components are also contained in the ink in the sub tank. Of course, it may be a substance different from the ink component. The second sealing liquid is “glycerin (50.00% by weight), antiseptic / antifungal agent (trade name: Proxel LV (Zeneca Corporation) (0.40% by weight). %), Water (remaining ) "Contains a. Third sealing liquid contains a" silicone grease (FS high vacuum grease) (Dow Corning) (100 wt%) ".

  The first application method is a method of transferring a liquid to a packing part after immersing the ball in a liquid using a jig in which a spherical application ball is attached to a rod. The second application method is a method in which the packing is directly immersed in the sealing liquid and then placed in a pressure control valve cap (corresponding to 133 in FIG. 7). The third application method is a method in which a ball is directly immersed in a seal solution and then placed on the packing.

  Table 1 shows the results of the sub-tank unit produced as described above. Here, when one embodiment of the present invention described above is applied, a preferable coating amount of the present embodiment is approximately “about 0.05 mg or more and 50 mg or less”. The application amounts of the first to eighth examples are included in the preferable application amount range. In addition, the comparative example 3 shows the case where the said sealing agent is not apply | coated.

  Here, the first to eighth examples obtained the most preferable effect, whereas Comparative Example 3 in which the sealant was not applied leaked immediately due to the adhesion of one hair. Moreover, although the comparative example 1 is contained in the said preferable application amount range, even within the range, since it is the smallest as “0.1 mg”, a sufficient effect cannot be obtained, and within 1 hour or more and 1 day at room temperature and normal humidity. Leaked completely. Further, in Comparative Example 2, although a good sealing effect was obtained, the amount of coating was larger than the above preferable range of coating amount, and thus the sealing agent flowed into the cap. Although the flow of the sealing liquid does not have an adverse effect immediately, it is not preferable because adhesion of foreign matters is accelerated in some cases.

  According to the present embodiment, even if foreign matter exists between the packing and the ball, long-term sealing performance is maintained at normal temperature and humidity.

[Second Embodiment]
In this embodiment, a fourth sealing liquid having a composition different from that of the first embodiment is prepared, and the packing of the sub-tank (FIG. 8) which is left in an environment different from that of the first embodiment (corresponding to 134 in FIG. 14). Yes, different adhesion amounts were applied to the ball as the contact / separation member (corresponding to 135 in FIG. 14) by the first application method, and the sealing effect was compared.

  Here, in the leaving environment, the valve part (packing, ball) coated with the fourth sealing liquid is provided in the sealed sub tank (sub tank unit), and the damper film (corresponding to 102 in FIG. 10) is recessed. In a sealed state, the temperature and humidity were lower than in the first example.

  The effect was judged by observing the leak state from the degree of opening of the damper film after being left in the environment described above. Specifically, “◎: One hair of foreign hair does not leak for 2 months or more at 50 ° C. and humidity of 4%” “▽: One hair of foreign hair does not leak for more than 1 month at 50 ° C. and humidity of 4%. However, if there is no hair, there is no leak. "

  The packing used was made of silicon rubber and had a height of “0.28 cm”, a diameter of “0.7 cm”, and an inner diameter of “0.3 cm”. The diameter of the ball is about “0.397 cm”.

  The first sealing liquid is “1,3-butanediol (22.50 wt%), glycerin (7.50 wt%), surfactant (1.00 wt%), antiseptic / antifungal agent (0.15 % By weight), pH adjuster (1.00% by weight), water (residue) ”. The fourth sealing liquid is “glycerin (70.0% by weight), antiseptic / antifungal agent (trade name: Proxel LV) (0.8% by weight), surfactant (polyoxyarlene alkyl ether (trade name: Softanol EP7025). : (Nippon Shokubai Co., Ltd.) (1.0 wt%), water (residue)).

  The first application method is a method of transferring a liquid to a packing part after immersing the ball in a liquid using a jig in which a spherical application ball is attached to a rod.

  Table 2 shows the results of the sub-tank unit produced as described above. Here, when one embodiment of the present invention described above is applied, a preferable coating amount of the present example is “about 0.05 mg or more and 50 mg or less”. The application amounts of the ninth to eleventh examples and the thirteenth example are included in the preferable application amount range.

  Here, the 10th to 12th examples gave the most preferable effects. In addition, the ninth example and the thirteenth example had the next preferable effect. The ninth example is included in the range of the preferable coating amount, but the most preferable result was not obtained in a high temperature and low humidity environment. The thirteenth example is included in the preferable application amount range, but since the glycerin content of the first seal liquid used in the thirteenth example is smaller than that of the fourth seal liquid, The environment did not give the most favorable results. Further, in the twelfth example, although a good sealing effect was obtained, the amount of the coating agent was larger than the above preferable range of the coating amount, so that the sealing agent flowed into the cap.

  According to the present embodiment, even if foreign matter exists between the packing and the ball, long-term sealing performance is maintained at high temperature and low humidity.

  In this example, since the severe condition of leaving for a long time in a high temperature and low humidity environment was set, evaporation of the sealing liquid itself also occurred. Under such harsh conditions, the glycerin, which is an organic solvent that is hard to evaporate, is more continuous than the first embodiment when the effect of preventing air leaks when one hair is mixed into the sealing liquid. high.

The liquid stored in the sub-tank is an ink containing at least pigment-containing polymer fine particles as a colorant and glycerin as a high-boiling organic solvent (for example, the composition of cyan ink is shown below), and is in contact with and separated from the packing. The effect of applying the sealing liquid when the sealant adhering between the members was used in the materials and amounts shown in the tenth and eleventh examples was confirmed with an inkjet printer. In this case, since glycerin, which is a high-boiling organic solvent that is the main component of the sealing agent, is also present in the ink, problems such as clogging of the head did not occur even when the sealing agent was scattered in the ink. In particular, when the viscosity of the pigment-containing polymer fine particles is as high as 5 mPa · sec or more, the jetting stability is often disturbed by the influence of impurities. Since there is no problem even if the sealing liquid of the air release valve is scattered and mixed in the ink, it is necessary to pay attention to the component, and there is no problem if it is a component of the present invention. If the ink itself is used as the sealant, the leakage of the air release valve increases due to the colorant.
[Examples of ink production]
An ink was prepared by the following method.
Reference Example 1 Preparation of Dispersion of Phthalocyanine Pigment-Containing Polymer Fine Particle A blue polymer fine particle dispersion was obtained by reexamining Preparation Example 3 disclosed in Japanese Patent Application Laid-Open No. 2001-139849. The average particle diameter (D50%) of the fine polymer particles measured by Microtrac UPA was 93 nm.
[Cyan ink]
An ink composition was prepared by the following method.

Phthalocyanine pigment-containing polymer fine particles ... 10.0 wt% (Reference Example 1) (as solids), 1,3-butanediol ... 25.0 wt%, glycerin _{... 8.5wt%, CH 3 (CH} 2) 12 O ( _{CH 2 CH 2 O) 3 CH} 2 COOH active agent ... 2.0 wt%, 2-ethyl-1,3-hexanediol ... 1.8 wt%, Proxel LV (antiseptic agent) ... 0.1 wt%, an antifoaming agent An ink composition was prepared by prescribing 0.05 wt%, ion-exchanged water and the remaining amount. The ink composition thus prepared was adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the ink composition. The viscosity of the ink composition thus obtained was 8.3 mPa · s at 25 ° C.

  As described above, in the pressure control mechanism according to the present invention, a liquid sealant different from a predetermined liquid (corresponding to “ink”) adheres to the contact portion between the contact / separation member (corresponding to “ball”) and the packing. By doing so, the sealing performance of the pressure control valve having the packing and the contact / separation member is improved, and the pressure control valve for opening to the atmosphere is equivalent to the packing and the contact / separation member ("opening / closing member"). It is useful as a pressure control mechanism and an ink jet recording apparatus that control the atmospheric pressure in the sub tank by opening and closing the pressure control valve.

FIG. 2 is a perspective explanatory view seen from the front side of the ink jet recording apparatus as an embodiment of the image forming apparatus according to the present invention. FIG. 2 is a configuration diagram illustrating an outline of a mechanism unit of the recording apparatus. It is principal part plane explanatory drawing of the mechanism part. It is explanatory drawing explaining the head structure of the apparatus. It is explanatory drawing explaining the other example of the head structure of the apparatus. It is a disassembled perspective explanatory drawing of the part which concerns on an ink supply apparatus. It is a disassembled perspective explanatory drawing of a sub tank. It is typical side surface explanatory drawing of the same sub tank. It is a schematic cross-sectional explanatory drawing which follows the AA line of FIG. It is explanatory drawing of a flexible film-like member. It is a plane explanatory view of a subsystem. It is a schematic structure explanatory drawing of a subsystem. FIG. 2 is a schematic block explanatory diagram of a control unit of the recording apparatus. It is an enlarged view of an open valve part (pressure control mechanism part).

Explanation of symbols

10, 10A, 10B ... Ink cartridge (main tank)
DESCRIPTION OF SYMBOLS 13 ... Carriage 14, 14a-14d ... Recording head 14yn, 14mn, 14cn, 14kn ... Nozzle row 15, 15A, 15B ... Sub tank 100 ... Ink storage part 102 ... Flexible film-like member 103 ... Spring (elastic member)
132 ... Air release valve mechanism 133 ... Holder 134 ... Valve seat (packing)
135 ... Ball (contact / separation member)
136 ... Spring 153 ... Air release pin 161 ... Lever

Claims (8)

A ring-shaped silicon rubber packing attached to an opening of a tank for filling ink containing a high-boiling water-soluble organic solvent, and a contacting / separating member comprising a metal sphere configured to be able to contact and separate from the silicon rubber packing When, said that moving assembly air to the tank by opening or closing the hole in the silicone rubber gasket enters and exits, pressure control means for said contacting and spacing member pressurizes controlling the air pressure in the tank, the provided, the contact portion of the silicone rubber gasket and said moving assembly is so the ink different from the liquid sealant adheres, the liquid sealant is a high-boiling water higher than the boiling point 100 ° C. at 1 atm Pressure control mechanism characterized by containing an organic solvent . The pressure control mechanism according to claim 1, wherein the liquid sealant contains a preservative and antifungal agent . When the radius of the metal sphere is d (cm), the liquid amount of the liquid sealing agent is 4πd ² × 0.1 (g) or less and 4πd ² × 0.0001 (g) or more. The pressure control mechanism according to claim 1. 2. The ink according to claim 1, wherein the ink contains pigment-containing polymer fine particles as a colorant, a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at 1 atmosphere, and a viscosity at 25 ° C. of 5 mPa · s or higher. 2. The pressure control mechanism according to 1. A head that ejects ink containing a high-boiling water-soluble organic solvent, a moving means that mounts the head and moves during recording, a detachable ink tank disposed outside the moving means, and an inside of the moving means And a sub tank for supplying the ink to the head, and a pressure control means for controlling the atmospheric pressure in the sub tank,
The pressure control means includes a ring-shaped silicon rubber packing attached to the opening of the sub tank, a contact / separation member made of a metal sphere configured to be able to contact and separate from the silicon rubber packing, and the contact / separation member. Pressurizing control means for controlling the atmospheric pressure in the sub tank by pressurizing the contact / separation member so that air enters and exits the sub tank by opening or sealing the hole of the silicon rubber packing,
A liquid sealant different from the ink adheres to the contact portion between the contact / separation member and the silicon rubber packing, and the liquid sealant contains a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or more at 1 atm. An ink jet recording apparatus containing the ink jet recording apparatus. 6. The ink jet recording apparatus according to claim 5 , wherein the liquid sealant contains an antiseptic / antifungal agent . When the radius of the metal sphere is d (cm), the liquid amount of the liquid sealing agent is 4πd ² × 0.1 (g) or less and 4πd ² × 0.0001 (g) or more. An ink jet recording apparatus according to claim 5 . The ink according to claim pigment-containing polymer fine particles as a colorant, a viscosity of 25 ° C. containing high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or more at one atmospheric pressure, characterized in that a more ink 5 mPa · s 5. An ink jet recording apparatus according to 5 .

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