JP4707498B2 - Recording liquid container and image forming apparatus - Google Patents

Description

  The present invention relates to a recording liquid container and an image forming apparatus.

  In general, as an image forming apparatus that combines a printer / fax / copier or a combination of these functions, an image forming unit that employs an electrophotographic method is known. For example, liquid discharge that discharges liquid droplets of recording liquid is known. Recording is performed while a recording medium (hereinafter also referred to as “paper” is not limited to a material, and the recording medium, a transfer material, and the like are also used synonymously) using a recording head constituted by a head. Some are equipped with an image forming unit of an ink jet system that performs image formation (recording, printing, printing, and printing are also used synonymously) by attaching liquid droplets (hereinafter also referred to as ink droplets) to paper. is there.

  In such an ink jet recording type image forming apparatus, a small-capacity recording liquid storage container (hereinafter referred to as “sub tank”) for supplying a recording liquid to a recording head is mounted on a carriage, and a large-capacity recording liquid storage means is used. There is known an apparatus in which a certain main cartridge (main tank) is installed on the apparatus main body side, and recording liquid (ink) is replenished and supplied to the sub tank from the main cartridge on the apparatus main body side.

As described in Japanese Patent Application Laid-Open No. H10-260826, such a subtank includes a print head, an ink reservoir in fluid communication with the print head, and ink received from an ink supply source outside the print cartridge. And an ink inlet port having a first interconnect member in fluid communication with the ink reservoir when the print cartridge is inserted into the scanning carriage in the printer in the first direction. A print cartridge in which the first interconnect member makes an airtight fluid connection with the second interconnect member on the scanning carriage and the fluid connection is automatically made when the print cartridge is inserted into the scan carriage in the first direction. A printing system is known.
Japanese Patent Laid-Open No. 10-128992

Further, as described in Patent Document 2, there is provided a carriage, at least one print head having an inlet port that is attached to the carriage and accessible without removing the print head, a bracket attached to the frame, and a bracket. At least one ink supply valve mounted, an automatic mechanism operably connected to the bracket, wherein the bracket and the ink supply valve are moved in a forward direction toward the carriage in a rest position, and the ink supply valve is moved to the carriage Some ink jet printing systems have an automatic mechanism that engages the inlet port of a printhead attached to the printer.
Japanese Patent Laid-Open No. 10-235892

Further, as described in Patent Document 3, a recording head mounted on a carriage and driven to reciprocate in the width direction of the recording paper, and mounted on the carriage together with the recording head, from a main ink tank via an ink supply path A sub-tank that receives ink supply and supplies ink to the recording head, and an air valve that communicates with the negative pressure generating means when the ink in the sub-tank falls below a predetermined level, opens the sub-tank to reduce the pressure in the sub-tank. Pressure reduction control means for closing the air valve that communicates with the negative pressure generating means when a certain amount of ink is filled in, and the pressure drop in the decompression path that communicates with the negative pressure generating means from the sub-tank By detecting this, it is possible to detect that a predetermined amount of ink has been filled into the sub tank from the main ink tank. It is also known location.
Japanese Patent No. 3053017

  However, the systems described in Patent Documents 1 and 2 described above do not have a function of discharging air mixed in the ink supply path by attaching and detaching the air permeability and moisture permeability of the tube and the ink replenishment unit. When a large amount of air enters the sub tank, the printing performance deteriorates. In order to avoid this, it is necessary to use only a disposable head with a short life, or use an expensive tube having characteristics of excellent air permeability and moisture permeability for the tube connecting the sub tank and the ink cartridge. There are problems such as.

  Further, in the apparatus described in Patent Document 3, since ink is filled while removing air from the sub tank, there is no problem of air accumulation as described above. However, each color 2 for supplying ink to the sub tank and for sucking air is used. Tubes must be connected, and the sub tank is mounted on the carriage and scanned, so the tube connected to the sub tank must have a minimum length corresponding to the scanning amount. There is a problem that you have to crawl around. In addition, there is a problem that the apparatus is expensive because it has a dedicated pump for generating negative pressure.

Therefore, as described in Patent Document 4, there is known a sub tank configured to generate a negative pressure inside due to a volume change.
JP 2003-237108 A

  By the way, in the image forming apparatus, since there is a demand for an increase in recording speed, the recording head is becoming longer. For example, even with a line-type head having a length corresponding to the paper width or a serial type, the length in the sub-scanning direction (paper feeding direction) is increased (the number of nozzles in the sub-scanning direction is increased) once for the carriage. The area to be recorded in this scan is increased.

  When a sub tank is provided for such a long recording head, the amount of recording liquid to be used increases as the number of nozzles of the recording head increases. If the conventional sub tank is used as it is, the recording liquid for the sub tank is not used. The number of replenishment supply increases. Further, in the case of a sub tank provided with means for generating a negative pressure by volume change as described in Patent Document 4 described above, the sub tank preferably has a square shape as much as possible. If the size is increased, the size of the sub tank is increased, and the carriage weight increases in the case of the serial type.

  Thus, when a sub-tank is provided for a long recording head, a technical problem that does not exist in the conventional sub-tank occurs, and no means for solving such a technical problem has been found.

  The present invention has been made in view of the above problems, and particularly includes a small and sufficient recording liquid storage container suitable for supplying a recording liquid to a long head, and the recording liquid storage container. Another object of the present invention is to provide an image forming apparatus.

In order to solve the above problems, a recording liquid storage container according to the present invention includes:
In the recording liquid storage container capable of generating a negative pressure due to volume change, supplying the recording liquid to a recording head that discharges recording liquid droplets from a nozzle and replenishing and supplying the recording liquid from the outside.
Has first, second reservoir chamber for accommodating the recording liquid,
A communication path is formed in the partition wall separating the first and second reservoir chambers,
The first reservoir chamber is provided with an openable / closable air communication port and a recording liquid discharge port for supplying a recording liquid to the recording head,
The second reservoir chamber is provided with a recording liquid injection port for injecting a recording liquid from the outside,
The first and second reservoir chambers are formed of a flexible film-like member having at least one surface sealed at its periphery, and elastically pressurizes the flexible film-like member in the direction of increasing the volume of the reservoir chamber. Members are provided,
The pressing force of the elastic member of the second reservoir chamber is weaker than the pressing force of the elastic member of the first reservoir chamber,
A means for detecting a change in volume of the second reservoir chamber is provided .

Here, the the first reservoir chamber may configured to have an openable air vent. A means for detecting air may be provided in the first reservoir chamber. The communication path of the partition may be provided on the side away from the recording liquid discharge port for supplying the recording liquid to the recording head.

An image forming apparatus according to the present invention includes the recording liquid container according to the present invention. Here, the recording liquid can be replenished and supplied in an open state and the recording liquid can be replenished and supplied in a non-atmospheric state . Moreover, it can be set as the structure provided with the means to open | release the said subtank temporarily to air | atmosphere based on ambient temperature .

According to the recording liquid storage container of the present invention, the first and second reservoir chambers for storing the recording liquid are provided, and the communication path is formed in the partition wall that separates the first and second reservoir chambers . The reservoir chamber is provided with a recording liquid discharge port for supplying the recording liquid to the recording head, and the second reservoir chamber is provided with a recording liquid injection port for injecting the recording liquid from the outside. The reservoir chamber is formed of a flexible film-like member having at least one surface sealed at its periphery, and an elastic member is provided to pressurize the flexible film-like member in the direction of increasing the volume of the reservoir chamber. The pressure applied to the elastic member of the reservoir chamber is weaker than the pressure applied to the elastic member of the first reservoir chamber, and is provided with means for detecting the volume change of the second reservoir chamber. Compact and suitable for supplying recording liquid to the head Recording liquid container having such capacity.

According to the image forming apparatus according to the present invention is provided with the recording liquid accommodating container according to the present invention, it is possible to increase the speed of recording speed by the long head of.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of a sub tank that is a recording liquid container according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic front view of the sub tank, and FIG. 2 is a schematic plan view of the sub tank.
This sub tank 1 is formed in a container main body (case main body) 1a with a plurality of (here, two) reservoir chambers 2A and 2B serving as ink storage portions for storing ink as recording liquid separated by a partition wall 1b. A communication passage 3 is formed in the partition wall 1b to communicate the reservoir chambers 2A and 2B. The sub tank 1a is attached to the recording head 10.

  The container body 1a is bonded with flexible film-like members (flexible film-like members) 4A and 4B that seal (seal) the openings (one surface of the sub-tanks) of the reservoir chambers 2A and 2B. Alternatively, the film-like members 4A and 4B are urged outwardly between the container body 1a and the film-like members 4A and 4B inside the reservoir chambers 2A and 2B. Springs (springs) 5A and 5B, which are elastic members for energizing in the direction of increasing the volume of 2B, are provided.

  Here, as shown in FIG. 1, the reservoir chambers 2A and 2B are formed in a substantially square shape with substantially the same length and height in the longitudinal direction of the recording head 10 that discharges the recording liquid droplets. Accordingly, the flexible film-like members 4A and 4B sealing the openings of the reservoir chambers 2A and 2B are substantially symmetrical in two orthogonal directions. Each flexible film-like member 4A, 4B is formed of a single flexible film-like member. These film-like members 4A and 4B and springs 5A and 5B which are elastic members constitute means for generating a negative pressure by changing the volume.

  The film-like members 4A and 4B may have a single-layer structure, but a two-layer structure in which different types of first and second layers are laminated, for example, a structure in which polyethylene and nylon film-like members are laminated, or the first It can be set as the structure etc. which formed the silica vapor deposition layer in the layer. By configuring the film-like member 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 aimed at by including a silica vapor deposition layer in a film-form member.

  The film-like members 4A and 4B are formed by molding into a shape having a bulging portion that is convex outwardly corresponding to the springs 5A and 5B, and stably hold the elastic members (springs here) 5A and 5B. To be able to.

  The reservoir chamber 2A communicates with the atmosphere above the reservoir chamber 2A in which the recording liquid discharge port (ink discharge port) 11 for supplying ink to the recording head 10 of the two reservoir chambers 2A and 2B is formed. An atmosphere communication port 12 is formed to communicate with the atmosphere via an atmosphere release valve 13. The ink discharge port 11 may be provided for each reservoir chamber or in two or more required reservoir chambers.

  Further, the reservoir chamber 2A is formed above the reservoir chamber 2A in which an ink discharge port 11 for supplying ink to the recording head 10 of the two reservoir chambers 2A and 2B and an atmosphere opening port 12 for releasing the atmosphere are formed. Detection electrodes 14 and 14 are provided as means for detecting the gas (in this case, air). The amount of gas (or ink) is changed by changing the conduction state between the detection electrodes 14 and 14 between the state in which the two detection electrodes 14 and 14 are both immersed in ink and the state in which at least one of the detection electrodes 14 and 14 is not immersed in ink. Can be detected.

  On the other hand, a recording liquid injection port (ink injection) for injecting ink as a recording liquid from the outside is provided above the reservoir chamber 2B in which the ink discharge port 11 and the air release port 12 of the two reservoir chambers 2A and 2B are not provided. Inlet 16 is formed. Through this ink inlet 16, the reservoir chamber 2 </ b> B is supplied with ink from a main ink tank (ink cartridge) 18 provided outside via a pump 17.

  Further, a detection lever 20 for detecting a volume change of the reservoir chamber 2B is provided corresponding to the reservoir chamber 2B. The detection lever 20 is supported by the container main body 1a so as to be swingable by a support shaft 21, and swings in accordance with the change of the film-like member 4B in the reservoir chamber 2B. Therefore, by detecting the position of the detection lever 20, the reservoir It can be detected that the chamber 2B is full.

  Further, the communication path 3 that connects the reservoir chamber 2A and the reservoir chamber 2B is provided on the opposite side of the ink discharge port 11, that is, at a position that connects the upper portion of the reservoir chamber 2A and the upper portion of the reservoir chamber 2B. Thereby, more ink can be supplied to the reservoir chambers 2B and 2A. In addition, air that tends to accumulate in the upper portions of the reservoir chambers 2B and 2A can be easily guided to the atmosphere opening port 12, and the bubble discharge performance is improved. Note that the communication path 3 is not limited to one, and a plurality of communication paths 3 may be provided.

In the sub tank 1 configured as described above, an operation of supplying ink and generating a negative pressure will be described.
First, the atmosphere release valve 13 is first opened, the reservoir chamber 2A and the reservoir chamber 2B communicating with the reservoir chamber 2A via the communication passage 3 are opened to the atmosphere, and then the pump 17 is operated. As a result, the ink in the ink cartridge 18 is injected from the ink injection port 16 and is first injected into the reservoir chamber 2 </ b> B while discharging the air originally in the sub tank to the outside through the atmosphere opening port 12 and the atmosphere opening valve 13. .

  When the ink level reaches the communication path 3, the ink flows into the reservoir chamber 2A. In order to supply a large amount of ink into the reservoir chambers 2 </ b> B and 2 </ b> A, the communication path 3 is preferably located above the sub tank, that is, on the side opposite to the ink discharge port 11 with respect to the recording head 10.

  Therefore, it is checked whether or not filling is completed by checking the decrease in electrical resistance between the detection electrodes 14 and 14 in the reservoir chamber 2A. When the ink reaches between the detection electrodes 14 and 14 and the electrical resistance decreases, the filling is completed. The operation of the pump 17 is stopped. Thereby, the reservoir chambers 2A and 2B of the sub tank 1 can be filled with ink.

  Thereafter, the air release valve 13 is closed to seal the reservoir chambers 2A and 2B in the sub tank 1, and the nozzle surface of the recording head 10 is capped with a capping member of a head maintenance / recovery mechanism (not shown). A suitable amount is sucked and discharged (nozzle suction). As the ink is discharged, the fill-like members 4A and 4B constituting one surface of the sub tank 1 are depressed, and negative pressure is generated inside by the action of the springs 5A and 5B inside the reservoirs 2A and 2B. It is possible to obtain a state in which ink can be ejected to form the ink.

  Further, when ink in the sub tank 1 is consumed by printing, the negative pressure gradually increases. If the negative pressure becomes too large, air is sucked from the nozzles of the recording head 10 and an abnormal image is formed. Therefore, before that, it is necessary to operate the pump 17 to replenish and supply ink. Since the film-like members 4A and 4B of the sub tank 1 swell when the ink is replenished, the detection lever 20 in contact with the film-like member 4B is swung, and the position of the detection lever 20 is detected by a detection means such as a photosensor. By doing so, the full tank can be detected, and the replenishment amount can be easily controlled.

  In this case, the negative pressure condition is basically the same as long as the sub-tank 1 is replenished with the same amount of ink used for printing, but there is a slight air layer in the sub-tank 1. Negative pressure is affected by temperature changes. Therefore, when the ambient temperature is detected and there is a large temperature change, ink is replenished and supplied once the atmosphere release valve 13 is opened and the atmosphere is released, as in the case of the initial filling described above. It is preferable to recreate the negative pressure by performing an operation of generating a negative pressure by performing nozzle suction. Thereby, stable recording liquid supply can be performed.

  By providing the air opening opening that can be opened and closed in this way, it is possible to refill the atmosphere and regenerate the negative pressure, and it is possible to maintain a highly reliable recording liquid supply over a long period of time. Further, by providing the air release port in the reservoir chamber having the ink discharge port for supplying ink to the recording head, it is easy to discharge the air mixed from the nozzle to the outside, and the possibility of air mixing into the head is reduced. be able to.

  Here, if a large amount of air remains in the sub tank 1, the fluctuation of the negative pressure in the ink container with the temperature change increases. Therefore, as shown in FIG. 3, a part 2a of the reservoir chamber 2A is raised and the detection electrode 14 is provided at the highest position in the reservoir 2A where the atmosphere opening 12 is provided, and is higher than the top surface of the reservoir chamber 2B. The structure provided in a high position is preferable.

  In addition, since the sub tank 1 is supplied with ink from the ink cartridge 18 to the reservoir chamber 2B, and the ink enters the reservoir chamber 2A via the communication path 3 and is supplied to the recording head 10, the ink in the sub tank 1 The circulation of the ink is good and the old ink is less likely to stay in the sub-tank 1, so that the quality of the ink can be stabilized.

  Furthermore, since the air release port 12 is formed on the top surface of the reservoir chamber 2 </ b> A communicating with the recording head 10, it is easy to discharge air that has entered the sub-tank 1 from the nozzles of the recording head 10.

  As described above, the sub tank (recording liquid storage container) has a plurality of reservoir chambers for storing the recording liquid separated by the partition walls, and a communication path is formed in the partition walls between the reservoir chambers. Therefore, it is possible to reduce the size while increasing the capacity of the recording liquid that can be stored, and to obtain a stable volume change even when a negative pressure is generated by the volume change.

  This point will be specifically described with reference to FIGS. A comparative example of the sub-tank in the case where the number of nozzles is increased and the length of the head is increased in order to perform high-speed printing will be described with reference to FIG. 4. FIG. 4A shows a normal size recording head 510 and recording head 510. A sub-tank 501 that uses a film-like member to generate negative pressure by volume change is shown in the same manner as described above.

  In this case, the length L1 of the sub tank 501 is substantially the same as the length of the recording head 510, and has a substantially square shape with the length L1 as one side. As the shape of the sub-tank 510, when a negative pressure is generated by a volume change using a film-like member, it is preferable that the deformation of the film-like member occurs as a starting point as much as possible in order to detect a full tank. It is preferable to use a substantially square shape.

  FIG. 4B is an example in which the long recording head 10 of the above embodiment with the increased number of nozzles is provided with the normal sub tank 501 of FIG. In this case, since the amount of ink used for high-speed printing increases, the sub tank 501 runs out of ink quickly, so the frequency of refilling and filling the sub tank 501 increases. In addition, when the ink cartridge configuration (use-up type without replenishment supply) is used instead of the subtank configuration, the replacement frequency increases.

  FIG. 4C shows an example in which the long recording head 10 is provided with a rectangular sub-tank 601 having a length L2 substantially the same as the length of the recording head 10 and a height L1. In this case, since the ink capacity that can be stored increases, the above-described disadvantages such as an increase in the filling frequency are eliminated, but the length and height of the film-like member are extremely different, and when the film-like member is stretched and formed, the amount of elongation Becomes inhomogeneous, and it is difficult to obtain stable quality, and stable deformation cannot be obtained (where the base point of deformation is not determined).

  4C, the long recording head 10 has a length L2 and a height L2 that are substantially the same as the length of the recording head 10, that is, a length that is substantially the same as the length of the recording head 10 as in the case of the normal sub tank 501. This is an example including a sub tank 701 having a square shape with one side as a side. In this case, the shape of the film-like member is substantially symmetrical both in the horizontal direction and in the height direction, the ink capacity is further increased, the frequency of ink replenishment is reduced, and the printing throughput as the recording apparatus is improved.

  However, in the configuration of FIG. 4C, when the air mixed in the sub-tank 701 is discharged to the atmosphere after being released to the atmosphere over time, the ink is discharged again to create a negative pressure. Since the size of the container in the height direction is large, there is a disadvantage that the amount of ink to be discharged in order to obtain an appropriate negative pressure is increased due to a large water head difference from the nozzle surface. Further, since the sub tank is enlarged, when mounted on the carriage, the carriage weight increases, main scanning becomes unstable, and the main scanning drive mechanism becomes larger.

  In contrast, as shown in FIG. 5, the sub-tank according to the present invention extends the length of the sub-tank 1 according to the length in the longitudinal direction of the recording head 10 without increasing the height of the sub-tank 1 itself. By forming two reservoir chambers 2A and 2B partitioned by a partition wall, each reservoir chamber 2A and 2B can be formed in a substantially square shape having a length L1 as one side.

  As a result, the film-like member has substantially the same dimensional relationship in the longitudinal direction and the height direction of the head, so that the molding quality of the film-like member is stabilized and a stable deformation of the film-like member can be obtained. . Further, since it does not extend in the height direction, even when the negative pressure is formed after the atmosphere is released by discharging the ink as described above, the amount of ink discarded can be reduced. Furthermore, even when the length is increased, the number of divisions can be increased.

Next, a second embodiment of a sub-tank that is a recording liquid container according to the present invention will be described with reference to FIG.
In this embodiment, for the springs 5A and 5B as elastic members provided in the reservoir chambers 2A and 2B, the pressure of the spring 5B of the reservoir chamber 2B is relatively weaker than the pressure of the spring 5A of the reservoir chamber 2A. The detection lever 20 is provided on the reservoir chamber 2B side where the pressure of the spring 5B is relatively weak. A sensor 22 for detecting the displacement of the detection lever 20 is disposed on the apparatus main body side.

  In the sub-tank 1, when ink is used from the state in which the reservoir chambers 5A and 5B are filled with ink as shown in FIG. 6A, the spring 5B having a weak pressure as shown in FIG. 6B. The detection lever 20 is displaced by the depression of the film-like member 4B on the reservoir chamber 2B side. Further, when ink is used, the film-like member 4A on the reservoir chamber 2A side having the spring 5A having a relatively strong pressing force is recessed as shown in FIG. From this state, when ink is filled, restoration is performed in the order of (c) → (b) → (a).

  Thus, by providing the reservoir chamber in which the pressure applied to the elastic member is relatively weak, the film-like member of the weak elastic member can be greatly deformed even in the region of weak negative pressure. If the detection means (displacement member) is kept in contact, the filling can be controlled easily.

Next, specific examples will be described with reference to the configuration examples of FIGS. 7 is a schematic front explanatory view of the sub tank, and FIG. 8 is a schematic plan explanatory view of the sub tank.
In this configuration example, the atmosphere release valve 13 includes a valve body (ball) 13A and a compression spring 13C that presses and biases the valve body 13A toward the valve seat 13B (biased in a closed state). At the same time, a solenoid 23 that presses the valve body 13A of the atmosphere release valve 13 from the outside to open is provided on the apparatus main body side.

First, Example 1 will be described.
A container main body 1a having a first reservoir chamber 2A and a second reservoir chamber 2B having a volume of about 7 cc sealed on one surface with flexible film-like members 4A and 4B was formed of polyethylene resin. The film-like members 4A and 4B were formed of a low-density polyethylene on the inner surface, nylon on the outer surface and a thickness of 80 μm in advance in a substantially mountain shape and joined by heat fusion.

  In the first reservoir chamber 2A, an ink discharge port 11 for the recording head 10 is formed and communicated with the second reservoir chamber 2B through a communication path 3 formed of a cutout of approximately 15 mm square. Further, the communication path 3 formed of a notch is provided in the vicinity of the top surface of the second reservoir chamber 2B.

  A first compression spring 5A is disposed in the first reservoir 2A, and a second compression spring 5B is disposed in the second reservoir chamber 2B. As the compression spring 5A, a spiral spring having a generated force of about 40 to 60 gf with respect to a displacement amount of 6 mm was used, and as the compression spring 5B, a spiral spring having a generated force of about 20 to 50 gf with respect to a displacement amount of 6 mm was used.

  A part of the top surface of the first reservoir chamber 2A is made higher than the top surface of the second reservoir chamber 2B, and the detection electrodes 14, 14 made of metal pins as replenishment completion sensors are provided by press-fitting at the top. . Further, an atmosphere opening port 12 composed of a through hole having a diameter of about 2 mm was formed in the vicinity of the same portion, and this atmosphere opening port 12 was provided with an atmosphere opening valve 13 that was normally closed by being biased by a spring 13C.

  On the other hand, an ink injection port 16 composed of a hole having a diameter of about 0.5 mm was formed in the upper part of the second reservoir chamber 2B, and a tube 19 having an inner diameter of 1 mm was connected to the ink injection port 16. The other end of the tube 19 was connected to the ink cartridge 18 via the piston pump 17. The ink cartridge 18 used was a bag shape made of aluminum vapor deposited film.

  Further, a resin lever part as a displacement member (detection lever) 20 is placed on the outer surface of the film-like member 4B of the second reservoir chamber 2B with a spring (not shown) with a force of about 5 to 10 g on the inside. It was provided so as to be pressurized. A photo sensor 22 that detects the displacement of the displacement member 20 is disposed at one end of the displacement member 20.

  A pressure sensor is provided in an opening (ink discharge port 11) to which the original recording head 10 is bonded on the bottom surface of the sub tank via a fluid resistance element set to a fluid resistance value equivalent to that of the recording head 10 for evaluation of the sub tank. Were joined. In this way, an evaluation sample was manufactured, ink filling operation was performed, and negative pressure was evaluated.

  First, the solenoid 23 is first driven from the outside, the pin 23a is inserted into the atmosphere release valve 13, the atmosphere release valve 13 is opened, and the film-like member 4B on the second reservoir chamber 2B side is displaced inward by about 1 mm. The volume in the sub tank 1 was decreased. The piston pump 17 was moved to fill the sub tank 1 with ink until the impedance between the electrodes 14 and 14 decreased, and the tank was full. In this state, when the internal pressure in the sub tank 1 was measured, the positive pressure was about 40 mmAq.

  Next, after releasing the pin 23a that pushes the air release valve 13 and sealing the inside, the restraint that the film-like member 4B is displaced inward is released, and the negative pressure is measured. The negative pressure was generated at 20 mmAq (the state shown in FIG. 6A described above).

  Next, when the ink was discharged, the negative pressure increased as the discharge amount increased, and at the stage where about 7 cc was discharged, the negative pressure became -100 mmAq. Here, since the spring 5B of the second reservoir chamber 2B is weak, the film-like member 3 is deformed in the order of FIG. 6 (a) → (b) → (c) as ink is discharged. The displacement member 20 was also displaced according to the deformation of the film-like member 4B of the second reservoir chamber 2B.

  Next, the ink replenishment pump 17 was driven without opening the air release valve 13. The replenishment stop was performed by detecting the position of the displacement member 20 and the output of the photosensor 22. Here, since the displacement of the one provided with the weak spring 5B is detected, the displacement of the displacement member 20 is large under the condition of a small negative pressure just before the end of filling, so that it can be accurately detected. As a result, replenishment could be stopped when the internal pressure was -20 mmAq.

Next, Example 2 will be described.
An ink jet recording apparatus mounted on a carriage was manufactured by connecting the recording head 10 to the sub-tank having the configuration of Example 1 above. As the recording head 10, a nozzle having a nozzle pitch of 150 dpi (about 169 μm pitch) and 320 nozzles / row was used.

  First, the solenoid 23 is driven from outside, the pin 23a is inserted, the atmosphere release valve 13 is opened, the piston pump 17 is moved, and ink is filled in the sub tank 1 until the impedance between the electrodes 14 and 14 decreases. And filled up. In this state, the pin 23a that pushes the air release valve 13 is released, the inside is sealed, the nozzle surface is capped and sucked, about 1 cc of ink is sucked and discharged, and then the wiping is performed to perform the recording head 10 nozzle surfaces were cleaned and the recording head 10 was filled with ink.

  The position of the displacement member 20 in the initial state is detected by the photo sensor 22 fixed on the apparatus main body side and the main scanning operation of the carriage, and is stored in the apparatus main body side, and then a plurality of sheets are printed.

  In this state, when the position of the displacement member 20 is detected again, it is deviated from the initial state, the film-like member is deformed as the ink is consumed, and the displacement member 20 is displaced corresponding to the deformation of the film-like member. I was able to confirm. When the pump 17 was moved to fill the ink and the printing was repeated until the displacement member 20 returned to the original position, a good image could be stably obtained.

Next, a third embodiment of a sub tank which is a recording liquid storage container according to the present invention will be described with reference to FIGS. 9 is a schematic front explanatory view of the sub tank, and FIG. 10 is a schematic plan explanatory view of the sub tank.
The sub-tank 31 of this embodiment is such that the reservoir chambers 1A and 1B are opened and sealed with film-like members 34A and 34B made of an elastic member having elasticity (restorability). (Spring) 5A and 5B are omitted.

Next, a fourth embodiment of a sub-tank that is a recording liquid container according to the present invention will be described with reference to FIG. FIG. 11 is a schematic front view of the sub tank.
The sub tank 41 of this embodiment forms five reservoir chambers 2A to 2E in the container main body 41a corresponding to the line type recording head 50 having a length corresponding to the paper width, and each of the partition chambers 31b of the mutual reservoir chambers. A communication path 3 is formed.

Next, an example of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 12 is an explanatory perspective view of the ink jet recording apparatus as the image forming apparatus as viewed from the front side.
The ink jet recording apparatus includes an apparatus main body 101, a paper feed tray 102 for loading paper mounted on the apparatus main body 101, and a sheet on which an image is recorded (formed) by being detachably mounted on the apparatus main body 102. And a paper discharge tray 103 for stocking. Further, a cartridge loading for loading an ink cartridge that protrudes from the front surface to the front side of the apparatus main body 101 and is lower than the upper surface is provided at one end of the front surface of the apparatus main body 101 (side of the paper supply / discharge tray section). The cartridge loading unit 104 has an operation / display unit 105 provided with operation buttons and a display.

  The cartridge loading unit 104 stores a plurality of recording liquids (inks) that are different color materials, such as black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink. Ink cartridges (main tanks) 110k, 110c, 110m, 110y (referred to as “ink cartridges 110” when the colors are not distinguished) are recording liquid cartridges as recording liquid storing means from the front side of the apparatus main body 101 to the rear. A front cover (cartridge cover) 106 that is opened when the ink cartridge 110 is attached or detached is provided on the front side of the cartridge loading unit 104 so as to be openable and closable.

  Further, the operation / display unit 105 has the remaining amounts of the ink cartridges 110k, 110c, 110m, and 110y for the respective colors at the arrangement positions corresponding to the installation positions (arrangement positions) of the ink cartridges 110k, 110c, 110m, and 110y for the respective colors. The remaining amount display sections 111k, 111c, 111m, and 111y for each color for displaying the near end and the end are arranged. Further, the operation / display unit 105 is also provided with a power button 112, a paper feed / print resume button 113, and a cancel button 114.

Next, the mechanism part of the ink jet recording apparatus will be described with reference to FIGS. FIG. 13 is a schematic side view illustrating the outline of the mechanism, and FIG.
The carriage 133 is slidably held in the main scanning direction by the guide rod 131 and the stay 132 which are horizontally mounted on the left and right side plates 122A and 122B constituting the frame 121, and the timing belt is held by a main scanning motor (not shown). Then, moving scanning is performed in the direction indicated by the arrow (carriage main scanning direction) in FIG.

  As described above, the carriage 133 is provided with a recording head 134 (four heads for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk)). A plurality of ink ejection openings are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  As an inkjet head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change due to liquid film boiling using an electrothermal conversion element such as a heating resistor, and a metal phase change due to a temperature change. It is possible to use a shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet.

  A driver IC is mounted on the recording head 134 and is connected to a control unit (not shown) via a harness (flexible print cable) 122.

  The carriage 133 is equipped with the sub-tank 1 described above which is a recording liquid storage container according to the present invention for each color for supplying each color ink to the recording head 134. Further, as described above, the inks of the respective colors are replenished and supplied from the ink cartridges 110 of the respective colors mounted on the cartridge loading unit 104 through the ink supply tubes 136 of the respective colors. The cartridge loading 104 is provided with a supply pump unit 124 for feeding ink in the ink cartridge 110.

  On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feeding tray 102, a half-moon roller (feeding) that separates and feeds the paper 142 from the paper stacking unit 141 one by one. A separation pad 144 made of a material having a large friction coefficient is provided facing the paper roller 143 and the paper feed roller 143, and the separation pad 144 is urged toward the paper feed roller 143 side.

  In order to feed the sheet 142 fed from the sheet feeding unit to the lower side of the recording head 134, a guide member 145 for guiding the sheet 142, a counter roller 146, a transport guide member 147, and a tip pressure roller. And a holding belt 148 that is a conveying means for electrostatically attracting the fed paper 142 and conveying it at a position facing the recording head 134.

  The conveyor belt 151 is an endless belt, and is configured to wrap around the conveyor roller 152 and the tension roller 153 and circulate in the belt conveyance direction (sub-scanning direction). Further, a charging roller 156 that is a charging unit for charging the surface of the transport belt 151 is provided. The charging roller 156 is disposed so as to come into contact with the surface layer of the conveyor belt 151 and to rotate following the rotation of the conveyor belt 151. Further, a guide member 157 is disposed on the back side of the conveyor belt 151 corresponding to the printing area by the recording head 134.

  The transport belt 151 rotates in the belt transport direction of FIG. 14 when the transport roller 152 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 142 recorded by the recording head 134, a separation claw 161 for separating the paper 142 from the conveying belt 151, a paper discharge roller 162, and a paper discharge roller 163 are provided. A paper discharge tray 103 is provided below the paper discharge roller 162.

  A double-sided unit 171 is detachably attached to the back surface of the apparatus main body 101. The duplex unit 171 takes in the paper 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds it again between the counter roller 146 and the transport belt 151. The upper surface of the duplex unit 171 is a manual feed tray 172.

  Further, as shown in FIG. 14, a maintenance / recovery mechanism 181 including a recovery means for maintaining and recovering the nozzle state of the recording head 134 is arranged in the non-printing area on one side of the carriage 133 in the scanning direction. Yes.

  The maintenance / recovery mechanism 181 includes cap members (hereinafter referred to as “caps”) 182a to 182d (hereinafter referred to as “caps 182” when not distinguished) for capping each nozzle surface of the recording head 134, and nozzle surfaces. A wiper blade 183 that is a blade member for wiping the ink, and an empty discharge receiver 184 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing. Here, the cap 182a is a suction and moisture retention cap, and the other caps 182b to 182d are moisture retention caps.

  Then, the waste liquid of the recording liquid generated by the maintenance / recovery operation by the maintenance / recovery mechanism 181, the ink discharged to the cap 182, the ink attached to the wiper blade 183 and removed by the wiper cleaner 185, and the idle ejection to the idle ejection receptacle 194 The discharged ink is discharged and stored in a waste liquid tank (not shown).

  Further, as shown in FIG. 14, in the non-printing area on the other side in the scanning direction of the carriage 133, 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 188 for receiving the droplets is disposed, and the empty discharge receiver 188 is provided with an opening 189 along the nozzle row direction of the recording head 134.

  In the ink jet recording apparatus configured as described above, the paper 142 is separated and fed one by one from the paper feed tray 102, and the paper 142 fed substantially vertically upward is guided by the guide 145, and the transport belt 151 and the counter roller 146, and the leading end is guided by the conveying guide 147 and pressed against the conveying belt 51 by the leading end pressing roller 149, and the conveying direction is changed by approximately 90 °.

  At this time, a charging voltage pattern in which a positive output and a negative output are alternately repeated from the AC bias supply unit of the control unit, which will be described later, to the charging roller 156 alternately, that is, an alternating voltage is applied and the conveying belt 151 is alternating. That is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction which is the circumferential direction. When the sheet 142 is fed onto the conveying belt 151 that is alternately charged with plus and minus, the sheet 142 is attracted to the conveying belt 151, and the sheet 142 is conveyed in the sub-scanning direction by the circumferential movement of the conveying belt 151.

  Therefore, by driving the recording head 134 according to the image signal while moving the carriage 133, ink droplets are ejected onto the stopped paper 142 to record one line, and after the paper 142 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 sheet 142 has reached the recording area, the recording operation is terminated and the sheet 142 is discharged onto the discharge tray 103.

  During printing (recording) standby, the carriage 133 is moved to the maintenance / recovery mechanism 181 side, the recording head 134 is capped by the cap 182, and the nozzles are kept in a wet state, thereby preventing ejection failure due to ink drying. . Further, the recording liquid is sucked from the nozzle by a suction pump (not shown) with the recording head 134 capped by the cap 182 (referred to as “nozzle suction” or “head suction”), and the thickened recording liquid and bubbles are discharged. Perform recovery action. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. As a result, the stable ejection performance of the recording head 134 is maintained.

Next, an outline of the control unit of the image forming apparatus will be described with reference to FIG. This figure is an overall block diagram of the control unit.
The control unit 300 controls the entire image forming apparatus, and includes a main control unit 301 composed of a microcomputer that also serves as a means for controlling replenishment supply to the sub tank 1 and a print control unit composed of a microcomputer that controls printing. 302.

  Then, the main control unit 301 sets the carriage 133 to form an image on the paper 142 based on information such as print data input from the communication circuit 201 from the host 400 such as a personal computer having the printer driver 401. The main scanning motor for moving in the main scanning direction and the sub scanning motor for moving the transport belt 151 in the paper feeding direction are driven and controlled via the main scanning motor drive circuit 303 and the sub scanning motor 304, and the print control unit Control such as sending print data to 302 is performed.

  Further, the main control unit 301 receives a detection signal from a carriage position detection circuit 305 that detects the position of the carriage 133, and the main control unit 301 controls the movement position and movement speed of the carriage 133 based on the detection signal. To do. The carriage position detection circuit 305 detects the position of the carriage 133 by, for example, reading and counting the number of slits of an encoder sheet arranged in the scanning direction of the carriage 133 with a photosensor mounted on the carriage 133. The main scanning motor drive circuit 303 rotates the main scanning motor 201 according to the carriage movement amount input from the main control unit 301 to move the carriage 133 to a predetermined position at a predetermined speed.

  The main control unit 301 receives a detection signal from a conveyance amount detection circuit 306 that detects the movement amount of the conveyance belt 151, and the main control unit 301 moves the movement amount and movement speed of the conveyance belt 151 based on the detection signal. To control. The carry amount detection circuit 306 detects the carry amount by, for example, reading and counting the number of slits of the rotary encoder sheet attached to the rotation shaft of the carry roller 152 with a photo sensor. The sub-scanning motor driving circuit 304 rotates the sub-scanning motor according to the conveyance amount input from the main control unit 301 to rotate the conveyance roller 152 to bring the conveyance belt 151 to a predetermined position at a predetermined speed. Move.

  The main control unit 301 rotates the sheet feeding roller 143 by giving a sheet feeding roller driving command to the sheet feeding roller driving circuit 307. The main control unit 301 causes the cap 182 to move up and down and the wiper blade 183 to move up and down by rotationally driving the motor of the maintenance and recovery mechanism 181 via the maintenance and recovery mechanism driving motor drive circuit 308.

  The main control unit 301 drives and controls an ink supply motor for driving the pump of the supply unit 124 via the ink supply motor drive circuit 311, and the ink cartridge 110 loaded in the cartridge loading unit 104 controls the sub tank 1. Supply ink. At this time, a solenoid (not shown) that opens and closes the atmosphere release valve of the sub tank 1 (corresponding to the solenoid 23 in the embodiment of the sub tank) is driven and controlled to perform atmosphere release filling or atmosphere non-open filling.

  The main control unit 301 corresponds to the detection lever of the sub tank 1 (corresponding to the detection lever 20 of the embodiment of the sub tank) when supplying the ink to the sub tank 1 with the carriage 133 at the position of the maintenance / recovery mechanism 181. ) Detects that the sub tank 1 is displaced to a full tank position, thereby detecting that the sub tank 1 is full, a detection signal from the sub tank full tank sensor 312, and a temperature sensor detecting the environmental temperature. A detection signal from 313 is input.

  The main control unit 301 also stores, via the cartridge communication circuit 314, non-volatile memories 215k, 215c, 215m, and 215y that are storage units provided in the ink cartridges 110 attached to the cartridge loading unit 4 The information stored in the volatile memory 215 ”) is taken in, required processing is performed, and the information is stored and held in a non-volatile memory (for example, EEPROM) 315 which is a main body storage means.

  Here, the remaining amount of the ink cartridge 110 is detected by reading out the remaining amount information stored in the non-volatile memory 215 of the ink cartridge 110 and temporarily storing it in the non-volatile memory 315 on the main body side. The number of ejected droplets from the ink is counted, the amount of ink used is calculated based on the count value, and the new ink remaining amount obtained based on the ink remaining amount and the ink amount used is subtracted from the ink cartridge 110 for each printing. 1 is written in the non-volatile memory 115 of the ink cartridge 110 every time ink is supplied. Then, the remaining amount of ink stored in the nonvolatile memory 215 of the ink cartridge 110 is read to detect the absence of ink (ink end or ink near end).

  The print control unit 302 generates pressure for ejecting droplets of the recording head 134 based on the signal from the main control unit 301 and the carriage position and conveyance amount from the carriage position detection circuit 305 and the conveyance amount detection circuit 306. Data for driving the means is generated and supplied to the head drive circuit 310.

  The head drive circuit 310 drives the pressure generating means (piezoelectric element in the case of a piezo head) of the recording head 134 based on the print data from the print control unit 302 to discharge droplets from a required nozzle.

  Therefore, the ink filling control for the sub tank 1 in this image forming apparatus will be described. The parts related to the sub tank 1 will be described using the same reference numerals as those in the first embodiment.

First, the operation of performing the open air filling to the sub tank 1 will be described with reference to FIG.
First, the atmosphere release valve 13 is first opened, the reservoir chamber 2A and the reservoir chamber 2B communicating with the reservoir chamber 2A via the communication path 3 are opened to the atmosphere, and then the ink supply pump 124 is operated. As a result, the ink in the ink cartridge 110 is injected from the ink injection port 16 and is first injected into the reservoir chamber 2 </ b> B while discharging the air originally in the sub tank to the outside through the atmosphere release port 12 and the atmosphere release valve 13. . When the ink level reaches the communication path 3, the ink flows into the reservoir chamber 2A.

  Therefore, it is checked whether or not filling is completed by checking the decrease in electrical resistance between the detection electrodes 14 and 14 in the reservoir chamber 2A. When the ink reaches between the detection electrodes 14 and 14 and the electrical resistance decreases, the filling is completed. Then, the operation of the ink supply pump 124 is stopped. Thereby, the reservoir chambers 2A and 2B of the sub tank 1 can be filled with ink.

  Thereafter, the air release valve 13 is closed to seal the reservoir chambers 2A and 2B in the sub tank 1, and the nozzle surface of the recording head 134 is capped by the capping 182a of the maintenance / recovery mechanism 181, and an appropriate amount of ink is supplied from the nozzles of the recording head 134. Suction and discharge (nozzle suction). As the ink is discharged, the fill-like members 4A and 4B constituting one surface of the sub tank 1 are depressed, and negative pressure is generated inside by the action of the springs 5A and 5B inside the reservoirs 2A and 2B. It is possible to obtain a state in which ink can be ejected to form the ink.

Next, an operation for performing non-atmospheric filling with respect to the sub tank 1 will be described with reference to FIG.
When the ink in the sub tank 1 is consumed by printing and the ink near end is detected, the ink supply pump 124 is operated to replenish and supply (fill) the ink to the sub tank 1. Then, as the film-like members 4A and 4B of the sub tank 1 swell due to replenishment of ink, the detection lever 20 in contact with the film-like member 4B swings, and the position of the detection lever 20 is detected by the sub tank full sensor 312. Detects full tank and stops filling. The ink near end is determined based on, for example, counting the number of droplets ejected from the recording head 134 and whether or not the integrated value has reached a set value.

Next, the operation of performing open air filling on the sub tank 1 based on the environmental temperature will be described with reference to FIG.
Here, the environmental temperature is detected based on the detection result of the temperature sensor 313, and it is determined whether or not the amount of change in the detected temperature is equal to or greater than a predetermined value. Refill the atmosphere with open air filling. That is, as described above, since there is a slight air layer in the sub-tank 1, if there is a large temperature change, the negative pressure is affected. If there is a large temperature change, the negative pressure is recreated.

  Note that the configuration of the subtank (recording liquid storage container) is not limited to that of the above-described embodiment, and any subtank that can generate a negative pressure by volume change may be used. 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.

FIG. 3 is a schematic front explanatory view for explaining a first embodiment of a sub tank which is a recording liquid storage container according to the present invention. It is a schematic plane explanatory drawing similarly. It is a typical front explanatory view explaining other examples of a sub tank of the embodiment. It is typical explanatory drawing which shows the example from which the subtank concerning a comparative example differs. It is typical explanatory drawing with which it uses for description of the effect of the subtank concerning the embodiment. FIG. 5 is a schematic plan view illustrating a second embodiment of a sub tank that is a recording liquid storage container according to the present invention. FIG. 7 is a schematic plan view for explaining a third embodiment of a sub tank that is a recording liquid container according to the present invention. It is a schematic plane explanatory drawing similarly. FIG. 9 is a schematic plan view illustrating a fourth embodiment of a sub tank that is a recording liquid storage container according to the present invention. It is a schematic plane explanatory drawing similarly. FIG. 10 is a schematic explanatory view for explaining a fifth embodiment of a sub tank which is a recording liquid container according to the present invention. FIG. 3 is a perspective explanatory view seen from the front side of the ink jet recording apparatus as the image forming apparatus according to the present invention. It is a side schematic block diagram explaining the whole structure of the mechanism part of the apparatus. It is principal part plane explanatory drawing of the mechanism part. It is block explanatory drawing which shows the outline | summary of the control part of the apparatus. It is a flowchart with which it uses for description of the operation | movement of the open atmosphere filling with respect to the sub tank which the control part of the apparatus performs. It is a flowchart with which it uses for description of the operation | movement of the non-atmospheric filling with respect to the sub tank which the control part of the apparatus performs. It is a flowchart with which it uses for description of operation | movement of the filling accompanying the temperature change with respect to the sub tank which the control part of the apparatus performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sub tank 1a ... Container main body 1b ... Partition 2A, 2B ... Reservoir chamber 3 ... Communication path 4 ... Flexible film-like member 5 ... Elastic member 11 ... Ink discharge port 12 ... Atmospheric release port 13 ... Ink injection port 101 ... Apparatus Main body 102 ... Paper feed tray 103 ... Paper discharge tray 104 ... Cartridge loading section 110k, 110c, 110m, 110y ... Ink cartridge 133 ... Carriage 134 ... Recording head 136 ... Ink supply tube 151 ... Conveying belt 301 ... Main control section

Claims (7)

In the recording liquid storage container capable of generating a negative pressure due to volume change, supplying the recording liquid to a recording head that discharges recording liquid droplets from a nozzle and replenishing and supplying the recording liquid from the outside.
Has first, second reservoir chamber for accommodating the recording liquid,
A communication path is formed in the partition wall separating the first and second reservoir chambers,
The first reservoir chamber is provided with a recording liquid discharge port for supplying a recording liquid to the recording head,
The second reservoir chamber is provided with a recording liquid injection port for injecting a recording liquid from the outside,
The first and second reservoir chambers are formed of a flexible film-like member having at least one surface sealed at its periphery, and elastically pressurizes the flexible film-like member in the direction of increasing the volume of the reservoir chamber. Members are provided,
The pressing force of the elastic member of the second reservoir chamber is weaker than the pressing force of the elastic member of the first reservoir chamber,
A recording liquid container, comprising means for detecting a change in volume of the second reservoir chamber .   2. The recording liquid container according to claim 1, wherein the first reservoir chamber has an air communication port that can be opened and closed. The recording liquid container according to claim 1 or 2, wherein means for detecting air is provided in the first reservoir chamber . 4. A recording liquid container according to claim 1 , wherein the communication path of the partition wall is provided on a side away from a recording liquid discharge port for supplying the recording liquid to the recording head. A recording head that discharges recording liquid droplets to a recording medium, and a sub-tank that supplies the recording liquid to the recording head and is replenished and supplied from the main recording liquid storage unit on the apparatus main body side. in the image forming apparatus, an image forming apparatus, wherein the sub-tank is a recording liquid container according to any one of claims 1 to 4. 6. The image forming apparatus according to claim 5, wherein the sub-tank can be replenished and supplied with recording liquid in an open state and replenished and supplied with recording liquid in a non-atmospheric state. 7. The image forming apparatus according to claim 6, further comprising means for temporarily releasing the sub tank to the atmosphere based on an ambient temperature .

Images