JP2007136807A - Ink supplying mechanism and inkjet recorder comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink supplying mechanism capable of adjusting negative pressure in a simple structure and correctly detecting timing for supplementing ink into a sub-tank, when the ink is reduced, to supplement the ink. <P>SOLUTION: A sub-tank body 1 is formed of a case 2 which is formed of a resin materials or the like and has an opening part on one wall surface. The opening part is sealed with a flexible and deformable member 3. The deformable member 3 is pressed to outside from the interior of case 2 with a pressure spring 4. A plate-like member 9 contacts in its belly part with the deformable member 3 which forms one wall surface of the case 2, using a fulcrum 10 as a fulcrum. The pressure spring 11 always energizes the plate-like member 9 in its belly part toward the deformable member 3. An optical sensor 12 such as a transmitting type photo-sensor or the like which detects the presence of a free end is arranged on the free end side of the plate-like member 9. The plate-like member 9 is provided with a protruding member 13 at the belly part in contact with the deformable member 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink supply mechanism in an ink jet recording apparatus.

  There is a so-called serial type as a main method of the ink jet recording apparatus. This is because the recording head is mounted on the carriage, the carriage is moved in the main scanning direction, the paper is transported in the sub-scanning direction (direction intersecting the main scanning direction), and ink droplets are transferred from the recording head to the paper surface of the paper. The recording is performed by discharging the ink. The recording head includes an ejection port that ejects ink droplets, a pressure chamber that communicates with the ejection port, and energy generation means that applies pressure to the pressure chamber.

  In such an ink jet recording apparatus, as a main form of supplying ink to the recording head mounted on the carriage, there is a form in which a print cartridge in which the recording head and the ink tank are integrated is mounted on the carriage. There is also a mode in which a recording head and a separate ink cartridge (also referred to as an ink tank) coupled to the recording head are mounted on the carriage. Furthermore, a device is also known in which iii) a recording head is mounted on a carriage and ink is supplied to the recording head by a tube from an ink cartridge installed in a non-moving portion other than the carriage.

  In such an ink jet recording apparatus, it is required to form a good ink meniscus at the ejection port and to make the ink pressure at the head part an appropriate negative pressure. For this purpose, it is necessary to take into consideration that ink dripping must be prevented when adopting a configuration in which the head is arranged downward, and that the ink inside does not foam due to sliding of the carriage.

  In order to generate an appropriate negative pressure, conventionally, in the above ink supply forms, i) and ii), an ink absorber made of a porous material is accommodated in the ink cartridge container body, and the capillary of this porous material is stored. Some of them absorb ink by force and generate negative pressure. This method is widely used because it is relatively easy to design and manufacture and has an advantage that the ink cartridge is easy to handle and can be made compact. However, as a matter of course, the volume of the absorber does not enter the ink, and the ink that can be held by the ink absorber so that the ink does not leak from the discharge port or the atmosphere opening while generating an appropriate negative pressure. Therefore, there is a limit to increasing the amount of ink.

  In addition, when only the ink cartridge is mounted on the carriage, the ink cartridge must be replaced with a new one each time it becomes empty. For this reason, in particular, when the frequency of ink use increases due to higher speed and higher image quality, the number of cartridge replacements increases, and more ink cartridges must be stored as spares.

  On the other hand, if the capacity of the ink cartridge is increased, the weight of the entire carriage increases, making it difficult to drive the carriage at high speed (high-speed printing), increasing the size of the apparatus, and increasing the output of the carriage drive motor. Since the weight variation of the carriage also increases, the operation characteristics of the carriage change during recording, making it difficult to ensure stable printing accuracy.

  On the other hand, in the ink supply form iii), an ink cartridge (referred to as a main cartridge in this form) is installed below the apparatus main body so as to generate a negative pressure rather than the recording head. Since the main cartridge does not require an absorber, it can accommodate more ink as long as the internal volume is the same as compared with the method using the absorber. In practice, however, a bag-shaped ink container is often used in order to easily release the negative pressure accompanying ink consumption.

  Further, as described above, it is necessary to form a good ink meniscus at the ejection port, and it is required to set the ink pressure at the head portion to an appropriate negative pressure. For this reason, it is necessary to prevent the ink meniscus from being destroyed due to an impact on the apparatus, and to reduce the negative pressure change caused by the swing accompanying the carriage movement. As a solution to this problem, there are methods disclosed in Patent Documents 1 and 2. More specifically, a sub-tank having a role of a buffer and mainly having a space portion positioned on the inside is mounted on a carriage located above the main cartridge and close to the recording head. There is a method using an apparatus in which a sub tank and a main cartridge are connected by a tube so that ink is replenished and supplied from the main cartridge to the sub tank.

  In this method, as disclosed in Patent Document 1, there is a method in which two tubes for ink supply and air suction are connected to a sub tank.

  In this method, ink is filled while removing air from the sub tank, so there is no problem of accumulation of air in the sub tank, but two tubes for ink supply and air suction must be connected to the sub tank. I must. In particular, in a color ink jet recording apparatus, for example, a total of eight tubes must be connected to each of the four sub-tanks of four colors.

  In this case, since the sub-tank is mounted on the carriage and scanned, the tube connected to the sub-tank must have a minimum length corresponding to the scanning amount, and many long tubes must be wound around in the apparatus. Challenges arise. In addition, a dedicated pump must be provided to generate the negative pressure, and the device is expensive.

  Therefore, as one of the improvement proposals, Patent Document 3 discloses a configuration in which a deformable film is attached to the side surface of the sub tank and a negative pressure is generated inside due to a volume change in the sub tank. The sub tank is provided with a displacement member including a film that deforms in accordance with the negative pressure in the sub tank and a leaf spring that displaces following the deformation of the film. When the ink in the sub tank is consumed, the displacement member is displaced following the movement of the film deformed in accordance with the change in the negative pressure in the sub tank. A method for replenishing ink into the sub-tank by detecting a detection piece provided on the leading end side of the displacement member by a detection means provided on the recording apparatus main body side has been proposed.

However, even with this method, there is a problem in that it is not possible to accurately detect the timing of ink replenishment into the sub tank when the ink in the sub tank is low.
Japanese Patent Laid-Open No. 5-16382 JP 2003-266734 A JP 2003-237108 A

  The present invention solves the problems of the background art described above. In other words, the negative pressure can be adjusted with a simple configuration, and the ink supply mechanism capable of accurately detecting the ink replenishment timing in the sub-tank when the amount of ink is reduced and the ink supply mechanism are provided. An object is to provide an ink jet recording apparatus. It is a further object of the present invention to provide an ink jet recording apparatus capable of performing stable recording for a long period of time with a highly reliable ink supply mechanism that improves the printing speed by reducing the number of ink replenishments. .

  In order to achieve the above object, the present invention includes a carriage, a recording head mounted on the carriage, a sub tank connected to the head, and a main tank installed outside the scanning area of the carriage. An ink supply mechanism for replenishing ink from the main tank to the sub-tank, wherein at least one wall surface constituting the outer wall of the sub-tank has an opening, and the opening is flexible The plate-like member is provided with a projecting portion that contacts the deformable member, and the plate-like member is a fulcrum portion that is in contact with the wall surface of the sub-tank at one end side. The other end is a free end that rotates about the fulcrum, and the projection of the plate-like member is displaced following the deformation of the deformable member. By detecting the member by detecting means, an ink supply mechanism to start replenishment of ink.

  According to the present invention, it is possible to adjust the negative pressure with a simple configuration, and it is possible to accurately detect the amount of ink in the sub tank and replenish ink. Furthermore, the number of ink replenishments is reduced, and stable recording can be performed for a long time.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a top view showing the main part of the ink supply mechanism according to the first embodiment of the present invention, and FIG. 2 is a top view showing the main part of a conventional ink supply mechanism compared with the present invention. 3A and 3B are diagrams for explaining the ink replenishment function to the sub-tank in the conventional example. FIG. 3A is a side view and FIG. 3B is a top view. 1 to 3 indicate the moving direction of the carriage on which the sub tank is mounted. Moreover, the same code | symbol is used for the same components in FIGS.

  First, the basic ink replenishment function for the sub tank will be described with reference to FIG. The sub tank referred to here is a container that is mounted on a carriage together with an ink jet recording head in a serial type ink jet recording apparatus, and is supplied with ink from a main tank installed at a place other than the carriage through a tube. Above this container is a space that serves as a buffer.

  The sub tank main body 1 shown in FIG. 3 is formed of a case 2 having an opening on one wall surface (in this example, one side surface) formed of a resin material or the like. An opening on one wall surface of the case 2 is closed with a deformable member 3 having flexibility. The deformable member 3 is pressed and urged outward from the inside of the case 2 by a compression spring 4. The case 2 is provided with an ink injection port (not shown) through which ink is injected into the ejection unit (inkjet recording head) 5. Here, the subtank main body 1 and the discharge unit 5 may be configured separately so that only the subtank main body 1 can be replaced, or the subtank main body 1 and the discharge unit 5 are integrated to form a head-integrated ink cartridge. May be configured.

  An ink tube 7 connected to a main tank (not shown) is introduced into the case 2 from the upper surface of the sub tank main body 1. Further, an atmospheric valve 6 capable of opening the inside of the case 2 to the atmosphere is provided on the upper portion of the sub tank main body 1. Further, an ink liquid level detection electrode 8 for detecting the ink liquid level is disposed above the sub tank main body 1.

  A plate-like member 9 is in contact with the deformable member 3 forming one wall surface of the case 2 with the fulcrum 10 as a fulcrum. The compression spring 11 constantly urges the plate-like member 9 toward the deformable member 3.

  An optical sensor 12 such as a transmissive photosensor for detecting the free end side of the plate-like member 9 is arranged on the recording apparatus main body side.

  Ink filling into the sub-tank main body 1 configured as described above is performed as follows. When the ink remaining amount in the sub tank decreases, the sub tank air valve 6 is pushed and opened in the direction of the arrow in FIG. 3A by means such as a solenoid provided on the recording apparatus side. Ink is supplied from the main cartridge of the recording apparatus into the sub tank main body 1 through the ink tube 7 by means such as a supply pump. Since the atmospheric valve is open, the sub-tank is at atmospheric pressure.

  When the ink is supplied into the sub tank main body 1 and the ink level detection electrode 8 is filled, the initial filling of the ink is finished and the atmospheric valve 6 is closed. FIG. 2A shows this state.

  Thereafter, when ink is consumed by a discharge state recovery operation (referred to as recovery suction) by suction with the nozzle surface of the discharge unit 5 being capped, or by ink discharge from the nozzles of the discharge unit 5 for recording, etc. A negative pressure is generated in the sub tank body 1. As the negative pressure is generated, the flexible deformable member 3 on one wall surface of the sub tank overcomes the urging force of the compression spring 4 and is drawn into the sub tank main body 1.

  At this time, the plate-like member 9 is in contact with the deformable member 3 with the fulcrum 10 as a fulcrum, and the compression spring 11 constantly urges the plate-like member 9 toward the deformable member 3. Therefore, as the ink is consumed as described above, the plate-like member 9 follows the deformable member 3 and rotates around the fulcrum 10.

  In a state where the deformable member 3 is drawn into the sub tank main body 1 against the force of the compression spring 4, the negative pressure in the sub tank main body 1 is increased by the force of the compression spring 4.

  Then, as shown in FIG. 2B, when the free end side of the plate-like member 9 is detected by the optical sensor 12, the supply pump in the recording device is operated without opening the atmospheric valve 6 from this state, Ink is supplied into the sub tank main body 1. The sub tank main body 1 is filled with ink, and as shown in FIG. 2A, the deformable member 3 swells outward and the volume in the sub tank main body 1 expands. The plate-shaped member 9 is also displaced when the deformable member 3 bulges outward by this ink replenishment.

  When a required amount of ink is replenished into the sub tank main body 1, the ink reaches the ink liquid level detection electrode 8, so that it is detected that the required amount of ink has been replenished into the ink container 1. . In response to the ink level detection signal, the operation of the supply pump is stopped, and the ink supply to the sub tank body 1 is stopped.

  Next, a first embodiment of the present invention will be described.

  The difference between this embodiment and the conventional example shown in FIG. 2 is that in FIG. 1, the plate-like member 9 is provided with a protruding member 13 in contact with the deformable member 3, and in FIGS. That is, there is no member 13. Other parts and dimensions are the same.

  FIG. 1A and FIG. 2A each show a state where the ink is filled up to the ink level detecting electrode 8 in the sub tank main body 1 and the initial filling is completed. FIG. 1B and FIG. 2B respectively show states when ink filling is started after the ink in the sub tank is used. The solid line arrow indicates the displacement of the position of the free end of the plate-like member 9.

  1A and 2A, the position of the free end portion of the plate-like member 9 when the sub tank main body 1 is filled with ink will be compared. In FIG. 1A which is an embodiment of the present invention, the distance between the free end position of the plate-like member 9 and the optical sensor 12 is A as shown. However, in FIG. 2A which is a conventional example, the distance between the free end position of the plate-like member 9 and the optical sensor 12 is B. This is because the plate-like member 9 of the present invention has a structure including the protruding member 13. The distance between the plate-like member 9 and the deformable member 3 is increased by the size of the protruding member 13, and as a result, when the ink in the sub tank is sufficiently filled, the distance between the optical sensor 12 and the plate-like member 9 is increased. It can be secured.

  When ink in the sub tank is used for recording, the deformable member 3 is drawn into the sub tank against the elastic force of the elastic member 4 as the ink is consumed. When the carriage moves in the direction indicated by the white arrow in the figure, the sub-tank on the carriage also moves in the direction of the white arrow, and the free end of the plate-like member 9 passes through the optical sensor 12 so that the inside of the sub-tank main body 1 Detect ink amount.

  In FIGS. 1 and 2, the distance between the optical sensor 12 and the free end of the plate-like member 9 in a state where the ink in the sub tank is full is A> B. In the configuration of the present invention, since the amount of movement of the free end of the plate-like member 9 corresponding to the amount of ink used in the sub tank is large, more detailed ink amount detection is possible.

  The ink replenishment to the sub tank will be specifically described.

  FIG. 1B and FIG. 2B are states when ink replenishment is started. As the ink is consumed, the deformable member 3 is drawn into the sub-tank. FIG. 1B, which is an embodiment of the present invention, has a configuration in which the plate-like member 9 includes the protruding member 13. Yes. As the ink is consumed, the protruding member 13 pushes the elastic member 4 in the sub-tank body 1, and as a result, the amount of ink remaining in the sub-tank body 1 can be reduced.

  On the other hand, FIG. 2B does not include the protruding member 13. Even when the deformable member 3 is drawn inside the sub tank main body 1 as the ink is consumed, the plate-like member 9 hits the wall surface of the sub tank case provided with the deformable member 3. The free end of the plate-like member 9 is detected by the optical sensor 12 in spite of the state where the ink still remains in the sub tank.

  By providing the projection 13 on the plate-like member 9 as in the present invention, the optical sensor 12 can detect the free end of the plate-like member 9 in a state where the ink in the sub tank is sufficiently consumed. Ink can be replenished into the sub tank at an optimal ink replenishment timing.

  Next, a second embodiment of the present invention will be described.

  FIG. 4 is a diagram illustrating the main part of the ink supply mechanism according to the second embodiment of the present invention. In the same figure, the same components as those shown in FIGS. FIG. 4A shows a state in which the ink in the sub tank main body 1 is consumed, the initial filling of the ink is completed, the ink is filled up to the liquid level detection electrode 8, and the sub tank is filled with ink. Yes. FIG. 4B shows a state when the ink in the sub tank is consumed and ink filling is started. The solid line arrow indicates the displacement of the position of the free end of the plate-like member 9.

  In the example shown in FIG. 4, a cutout portion 14 is provided on the wall of the sub-tank body 1 including the deformable member 3 as a receiving portion into which the plate-like member 9 can enter toward the wall facing the wall. It has been. Specifically, as the ink is consumed, the plate-like member 9 follows the deformable member 3 of the sub-tank main body 1 and rotates around the fulcrum 10, so that the portion on the free end side of the plate-like member 9 moves to the sub-tank main body 1. It has a structure that can enter the notch 14 provided on the wall surface.

  The movement distance of the plate-like member 9 is C in FIG. 4 when the sub tank is sufficiently filled with ink and when ink filling is started to replenish the sub tank with ink. The amount of movement of the plate-like member 9 to the optical sensor 12 is larger than that in the first embodiment.

  For this reason, even when compared with the first embodiment, it is possible to detect the remaining ink state in the sub-tank main body 1 until more ink is consumed.

  The difference in the displacement amount of the position of the free end of the plate-like member 9 when the ink filling is started again after the completion of the initial ink filling detected by the optical sensor 12 is shown in FIGS. In comparison with a) and FIG. 2A, it is clear that C> A> B.

  The first embodiment and the second embodiment of the present invention have been described above. In addition, in these embodiments, the material of the deformable member 3 is excellent in ink resistance, such as polyethylene and polypropylene, It is preferable that the resin material is inexpensive and easy to process. Further, such resin material may be laminated with nylon or the like for strength reinforcement, or may be formed by depositing aluminum or laminating an aluminum thin film to prevent ink evaporation. . More preferably, rubber materials such as butyl rubber and chlorinated butyl rubber, which are easy to follow the ink amount change in the tank, are excellent in ink resistance and gas permeability like resin materials, are inexpensive and easy to process. Is desirable.

  In the ink supply mechanisms according to the first and second embodiments described above, the deformable member 3 having flexibility is drawn into the sub-tank body 1 by providing the projection member 13 on the plate-like member 9. Even in this case, the state of the ink inside the sub tank main body 1 can be detected. Further, by providing the notch portion 14 on a part of the wall surface of the sub tank main body 1, the ink state inside the sub tank main body 1 can be detected until more ink is consumed.

  The stroke of the free end of the plate-like member 9 up to the position of the detection sensor 12 can be made large. It is possible to detect the amount of ink remaining in the sub-tank to a smaller state. Therefore, ink can be replenished at an optimal timing, and the number of ink replenishments can be reduced.

  Further, by making the deformable member 3 a rubber member, the amount of displacement of the free end of the plate-like member 9 is stabilized, and an ink supply mechanism that operates more accurately and stably can be obtained.

  Next, an example of an ink jet recording apparatus suitable for the ink supply mechanism according to the present invention will be described with reference to FIG. FIG. 5 is a perspective explanatory view for explaining a main configuration of the ink jet recording apparatus. The ink jet recording apparatus includes a carriage 113 that can move in the main scanning direction inside the recording apparatus main body 101.

  The carriage 113 is slidably held in the main scanning direction by a main guide rod 111 and a sub guide rod 112 which are guide members horizontally mounted on a side plate of the recording apparatus main body. The carriage 113 is fixed to the wound timing belt 115 and is moved in the main scanning direction by driving the timing belt 115 by the main scanning motor 114.

  An ink jet head (recording head) that ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) is disposed on the carriage 113, and the ink ejection port intersects the main scanning direction. The ink droplets are mounted with the ink droplet ejection direction facing downward. In addition, ink containers (ink tanks) for the respective colors that supply ink to the recording heads are mounted. Each color ink container is a combination of the sub-tanks of the first or second embodiment described above.

  The ink containers of the respective colors are placed on the carriage 113 in a state where the distances A, B, and C are secured so that the plate-like member 9 of the present invention can move as the ink is consumed when the ink in the sub tank is full. They are arranged side by side.

  Also, the main tanks 118 for the respective colors for replenishing the sub tanks for the respective colors are installed inside the recording apparatus in a replaceable manner in the sub tanks mounted on the carriage 113 and the portions where the head does not move. Ink is supplied from each main tank 118 to the sub tank via a flexible ink tube (not shown).

  During recording, the recording head is driven according to the image signal while moving the carriage 113, thereby ejecting ink droplets onto a stopped sheet-like recording medium such as paper or cloth to record one line. Then, after the recording medium is conveyed by a predetermined amount by the sub-scanning mechanism including the sub-scanning motor 116, the next line is recorded. Upon receiving a recording end signal or a signal that the rear end of the recording medium has reached the recording area, the recording operation is terminated and the recording medium is ejected from the apparatus.

  Further, a recovery device 117 for recovering the ejection failure of the head is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 113. The recovery device 117 includes a cap unit, a suction unit, and a cleaning unit.

  The carriage 113 is moved to the recovery device 117 side during printing standby and the head is capped by the capping means, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When replacing the ink cartridge or when an ejection failure occurs, the ejection port of the head is sealed with a capping unit. Then, bubbles and the like are sucked out together with ink from the discharge port by the suction means through the tube, and the ink and dust adhering to the surface of the discharge port are removed by the cleaning means to recover the discharge failure. Ink suction recovery is also performed after ink replenishment is completed after the ink in the sub-tank is low. By the suction recovery operation after the completion of ink replenishment, it is possible to ensure a negative pressure sufficient to discharge ink in the sub tank. The sucked ink is discharged to a waste ink reservoir installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

It is a top view explaining the principal part of the ink supply mechanism by the 1st Embodiment of this invention. It is a top view explaining the principal part of the ink supply mechanism as a prior art example compared with this invention. It is a figure for demonstrating the ink replenishment function to the subtank in the prior art example of FIG. It is a top view explaining the principal part of the ink supply mechanism by the 2nd Embodiment of this invention. 1 is a perspective view illustrating a configuration example of an ink jet recording apparatus suitable for an ink supply mechanism of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sub tank main body 2 Case 3 Deformable member 4, 11 Compression spring 5 Discharge part (inkjet recording head)
6 Atmospheric valve 7 Ink tube 8 Ink liquid level detection electrode 9 Plate member 10 Support point 12 Optical sensor 13 Protruding member 14 Notch

Claims (4)

In an ink jet recording apparatus comprising a carriage, a recording head mounted on the carriage, a sub tank connected to the head, and a main tank installed outside the scanning area of the carriage,
An ink supply mechanism for replenishing ink from the main tank to the sub tank,
At least one wall surface constituting the outer wall of the sub tank includes an opening,
A deformable member having flexibility for closing the opening;
It is configured to include a plate-like member having a protruding portion that is in contact with the deformable member,
The plate-like member is a fulcrum part that is in contact with the wall surface of the sub tank at one end side, and is a free end that rotates around the fulcrum part at the other end side.
An ink supply mechanism that starts replenishment of ink by detecting the plate-like member by detecting the plate-like member by displacing the protrusion of the plate-like member following the deformation of the deformable member.   The ink supply mechanism according to claim 1, wherein a receiving portion into which the plate-like member enters is formed in a wall of the sub tank provided with the deformable member.   The ink supply mechanism according to claim 1, wherein the deformable member is made of a rubber material.   An ink jet recording apparatus comprising the ink supply mechanism according to claim 1.

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