JP5332704B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a liquid container and an image forming apparatus, and more particularly to an image forming apparatus provided with a recording head for discharging droplets and a liquid container used in the image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, a copier, a plotter, or a multi-function machine having some of these functions, for example, a recording head composed of a liquid ejection head that ejects liquid droplets is used as a medium. (Hereinafter also referred to as “paper”, the material is not limited, and the recording medium, recording medium, transfer material, recording paper, etc. are also used synonymously.) Some perform image formation (recording, printing, printing, and printing are also used synonymously).

  In the present invention, the “image forming apparatus” means an apparatus that forms an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics or the like. In addition, “image formation” not only applies an image having a meaning such as a character or a figure to a medium, but also applies an image having no meaning such as a pattern to the medium (liquid is applied to the medium). It also means to attach). In addition, “ink” is not limited to ink in a strict sense, but is used as a general term for liquids that can perform image formation in the above sense, such as what is called ink, resist, DNA sample, and the like. .

  In such an image forming apparatus (hereinafter, also simply referred to as “inkjet recording apparatus”), a sub tank (also referred to as a buffer tank) that supplies ink to a recording head is mounted on a carriage, and a main ink cartridge ( (Also called the main tank) is installed on the main unit side, and the sub tank is equipped with an ink cartridge that is replenished and supplied from the main unit ink cartridge, or an ink cartridge that is a liquid container that can be replaced with the recording head. Devices that do this are known.

  Conventionally, as a sub-tank, there is an air release mechanism that opens the inside to the atmosphere, and a sealant is attached to a contact portion between a packing constituting the air release mechanism and a contact / separation member that contacts and separates the packing. Known (Patent Document 1).

JP-A-2005-169664

  The sub-tank (liquid container) having the air release mechanism as described above has a seal member for opening and closing an air release path that communicates the atmosphere and the inside of the sub-tank, but when the air flows into the sub-tank. If foreign matter such as dust or dust in the air enters the seal member, the foreign matter may adhere to the seal member and the sealing performance may deteriorate. When the sealing performance is lowered, the inside of the sub tank is always in communication with the atmosphere, so that the function of the sub tank, for example, generation of negative pressure becomes difficult.

  Therefore, in order to suppress the deterioration of the sealing performance due to the foreign matter, a seal auxiliary material such as grease is applied, and the gap due to the foreign matter is filled with the seal auxiliary agent.

  However, a high-viscosity seal assisting material having a high seal assisting property may block the air communication path itself. On the other hand, if a low-viscosity seal auxiliary material with high fluidity is used so as not to block the air communication passage, deterioration due to changes in environmental conditions (drying, etc.) and durability ( There is a problem in that deterioration of seal assistability due to movement occurs.

  The present invention has been made in view of the above-described problems, and an object thereof is to maintain stable seal assistability.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A recording head for discharging droplets;
A liquid storage container for storing a liquid to be supplied to the recording head,
The liquid container is
An atmosphere release mechanism having a seal member that opens and closes an atmosphere release path that opens the inside of the container body containing the liquid to the atmosphere;
An auxiliary material supply member containing a sealing auxiliary material that is a water-soluble organic solvent is provided on the sealing member of the atmosphere opening mechanism,
The seal member is formed of a member that can be deformed according to an opening / closing operation,
The auxiliary material supply member can be deformed according to the deformation of the seal member,
Means for supplying the seal auxiliary material to the auxiliary material supply member from the outside through the communication path formed in the holder member of the atmosphere release mechanism;
At the time of air shut-off of the atmosphere release mechanism, the auxiliary material supply member is also crushed by being crushed, the seal auxiliary material oozes out from the auxiliary material supply member and is supplied to the seal member,
The communication path is closed by the seal member when the atmosphere is shut off, and is opened when the atmosphere release mechanism is opened to the atmosphere when the seal member is separated from the outside to the auxiliary material supply member through the communication path. The seal auxiliary material is supplied dropwise.

  According to the image forming apparatus of the present invention, since the apparatus includes the means for supplying the seal auxiliary material to the seal member of the atmosphere release mechanism, the atmosphere communication mechanism can be stably sealed without obstructing the atmosphere communication function. Can be ensured for a long time.

1 is a schematic side view illustrating the overall configuration of an inkjet recording apparatus as an image forming apparatus according to the present invention that includes a liquid container (sub tank) 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 the liquid container. 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 an expanded sectional explanatory view of the atmosphere release mechanism of the liquid container concerning a 2nd embodiment of the present invention. It is sectional explanatory drawing of the filter holding member of the same air release mechanism. It is a perspective explanatory view of a filter holding member. It is an expanded sectional explanatory view of the atmosphere open mechanism of the liquid container concerning a 3rd embodiment of the present invention.

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 including the liquid container according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. 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.

  Further, the carriage 33 is equipped with sub tanks 35a and 35b (hereinafter referred to as “sub tanks 35” when not distinguished) that are liquid storage containers for supplying ink of each color corresponding to the nozzle rows of the recording head 34. Yes. 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, a sub tank which is a liquid container in the first embodiment of the present invention 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, an atmosphere release mechanism in the sub tank 35 will be described with reference to FIG. FIG. 6 is an explanatory sectional view of the air release mechanism portion.
The air release mechanism 204 is integrally provided with a hollow holder attachment portion 221 that forms an air release path 220 that communicates with the inside and outside of the container body 202 through the atmosphere release passage 203 on the upper side of the container body 202. A holder 222 serving as a cylindrical holding member is attached to the holder mounting portion 221.

  A valve member 231 is slidably mounted in the holder 222. As shown in FIG. 8, the valve member 231 includes a valve body portion 232 and an opening member portion 233 integrated with the valve body portion 232. A deformable seal member 234 is fitted to the valve member 231, and the valve member 231 is attached in a direction in which the valve body portion 232 presses the seal member 234 toward the stepped portion 222 a of the holder 222 by a spring 235. It is energized.

  Further, the opening member portion 233 of the valve member 231 is formed with a groove 233 a that forms an atmosphere communication path 241 that is a part of the atmosphere opening path 220.

  Further, the holder 222 holds a filter member 243 whose outer surface is in contact with the atmosphere, and is interposed between the air chamber 244 facing the inner surface side of the filter member 243, the air chamber 244, and the atmosphere communication path 242. A communication passage 245 having a smaller opening cross-sectional area in a direction orthogonal to the air inflow direction than 244 is provided. The communication path 245 faces the atmosphere opening path 242 in a direction orthogonal to the moving direction of the opening member portion 233. Moreover, the opening to which the filter member 243 of the air chamber 244 is attached is opened downward in the vertical direction.

  A cap member 265 as an elastically deformable sealing member that covers the opening member portion 233 of the valve member 231 is attached to the end portion side of the holder 222.

  In this atmosphere release mechanism 204, as shown in FIG. 6, when the seal member 234 is pressed against the stepped portion 222a side of the holder 222 by the valve body portion 232 of the valve member 231, the atmosphere release path 220 is shielded. 7, when the opening / closing member portion 233 of the valve member 231 is pushed in from the outside through the cap member 265, the valve body portion 232 moves inward with the seal member 234, and the atmosphere communication passage 220 is opened. .

Next, the supply of the seal auxiliary agent to the seal member 234 in the atmosphere release mechanism 204 will be described.
The seal member 234 has convex portions 234a and 234a at both ends in the moving direction, and a deformable auxiliary agent holding member 250 made of a felt member or the like containing and holding a seal auxiliary agent such as grease is fitted in the outer peripheral portion of the center portion. It has been.

  Here, as the seal auxiliary agent, when the seal member 234 is an organic substance, for example, a water-soluble organic solvent is preferable in order not to dissolve the seal member 234. That is, a high-boiling water-soluble organic solvent having a boiling point of 100 ° C. or higher at least 1 atm is preferable. In addition, although the seal member 234 does not come into contact with the ink, in order to avoid the evaporated component of the seal auxiliary agent from being mixed with the ink in the sub tank 35 and affecting the jetting stability, there is no problem even if it is mixed with the ink. In this respect, a high-boiling water-soluble organic solvent is preferable. In particular, the same solvent as the high-boiling water-soluble organic solvent contained in the ink is preferable.

  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.

  With this configuration, when the atmosphere is shut off, the seal member 234 is crushed and the auxiliary agent holding member 250 is also crushed, so that the seal auxiliary agent exudes from the auxiliary agent holding member 250 and is supplied to the seal member 234. The sealing performance by the seal member 234 is assisted.

  Further, the auxiliary agent holding member 250 is provided with an auxiliary agent supply unit 261 containing the auxiliary sealant 260 for supplying the auxiliary sealant from the outside, and the holder 222 is supplied with the auxiliary sealant 260 from the auxiliary agent supply unit 261 to the inside. A communication path 262 to be supplied is formed.

  The communication path 262 is closed by the projection 234a of the seal member 234 when the atmosphere is shut off, and is opened when the projection 234a of the seal member 234 is separated when the atmosphere is released. From 261, the seal auxiliary agent 260 is dropped and supplied to the auxiliary agent holding member 250.

  As described above, by providing a means for supplying the seal auxiliary material to the seal member of the atmosphere release mechanism, it is possible to ensure a stable sealing performance of the atmosphere communication mechanism for a long time without hindering the atmosphere communication function. Can do.

  Further, by supplying the seal auxiliary material from the outside, it becomes possible to supply the seal auxiliary agent more stably.

  In other words, a high-viscosity seal auxiliary material with a high sealing auxiliary property may block the atmosphere communication path itself, but a low-viscosity seal auxiliary material flows in accordance with a member that opens and closes the atmospheric communication path, Since it flows by the flow, it does not hinder the air communication function. Therefore, by using the seal auxiliary material mixed with a volatile solvent such as alcohol, a thin film of the low viscosity seal auxiliary material can be formed on the seal member. However, if the seal auxiliary material is dried, the seal auxiliary performance is weak. Therefore, it becomes necessary to periodically supply a seal aid.

  In this case, rather than storing and holding a necessary amount of the seal auxiliary agent inside the air release mechanism, the seal release agent is stably supplied without increasing the size of the air release mechanism by supplying the seal auxiliary agent from the outside. The supply can be performed.

Next, a second embodiment of the present invention will be described with reference to FIG. In addition, FIG. 9 is explanatory drawing of the air release mechanism part in the embodiment.
Here, the seal auxiliary agent 260 accommodated in the auxiliary agent supply unit 261 is pumped by the pump 270. As the pump 270, a tubing pump, a piston pump, a diaphragm pump, or the like can be used. Note that a check valve (not shown) is disposed in the communication path 262.

  By supplying the seal auxiliary agent 260 with the pump 270 in this way, there is no need to arrange the seal auxiliary agent accommodating portion (auxiliary agent supply portion 261) in the vicinity of the atmosphere communication path, and an auxiliary agent holding member, It is not always necessary to supply the seal member from the upper side in the direction of gravity (in this case, a check valve for preventing a backflow from the seal member side is interposed). Further, the supply and application to the seal member can be performed directly without using the auxiliary agent holding member.

Next, a third embodiment of the present invention will be described with reference to FIG. In addition, FIG. 10 is explanatory drawing of the air release mechanism part in the embodiment.
Here, the auxiliary agent supply unit 261 is disposed adjacent to the flexible bag-like auxiliary agent storage unit 271 that stores the seal auxiliary agent 260 and the auxiliary agent storage unit agent 271, and is supplied with air. And a pressurizing part 272 that expands and pressurizes the auxiliary agent accommodating part 271, and air is sent to the pressurizing part 272 by a pump 270. Note that a check valve (not shown) is disposed in the communication path 262.

  Even if it does in this way, similarly to the said 2nd Embodiment, it is not necessary to arrange | position the accommodating part (auxiliary agent supply part 261) of a sealing auxiliary agent in the vicinity of an air | atmosphere communication path, and also an auxiliary agent holding member and a sealing member However, it is not always necessary to supply from the upper side in the direction of gravity. Further, the supply and application to the seal member can be performed directly without using the auxiliary agent holding member.

  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 composite function such as a printer / facsimile / copying. It may be applied to a forming apparatus.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed tray 3 Paper discharge tray 33 Carriage 34 Recording head 35 Sub tank (liquid storage container)
DESCRIPTION OF SYMBOLS 51 Conveying belt 201 Ink accommodating part 202 Container main body 203 Atmospheric release path 204 Atmospheric release mechanism 220 Atmospheric release path 221 Holder attaching part 222 Holder 231 Valve member 232 Valve body part 233 Opening member part 234 Seal member 250 Auxiliary agent holding member 260 Seal auxiliary Agent 261 Auxiliary Agent Supply Unit

Claims (1)

A recording head for discharging droplets;
A liquid storage container for storing a liquid to be supplied to the recording head,
The liquid container is
An atmosphere release mechanism having a seal member that opens and closes an atmosphere release path that opens the inside of the container body containing the liquid to the atmosphere;
An auxiliary material supply member containing a sealing auxiliary material that is a water-soluble organic solvent is provided on the sealing member of the atmosphere opening mechanism,
The seal member is formed of a member that can be deformed according to an opening / closing operation,
The auxiliary material supply member can be deformed according to the deformation of the seal member,
Means for supplying the seal auxiliary material to the auxiliary material supply member from the outside through the communication path formed in the holder member of the atmosphere release mechanism;
At the time of air shut-off of the atmosphere release mechanism, the auxiliary material supply member is also crushed by being crushed, the seal auxiliary material oozes out from the auxiliary material supply member and is supplied to the seal member,
The communication path is closed by the seal member when the atmosphere is shut off, and is opened when the atmosphere release mechanism is opened to the atmosphere when the seal member is separated from the outside to the auxiliary material supply member through the communication path. An image forming apparatus, wherein the seal auxiliary material is dropped and supplied.

Images