JP2015206280A - Tube pump and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube pump, along with an image formation device including the same, capable of driving a plurality of pump units with a single drive source, in constant driving without on/off control, with no use of a sensor or the like, by suppressing pressure rising.SOLUTION: A tube pump 200 includes a tube 204 which is provided in a closed space 203 in a pump case 202 through which liquid passes, a pressurizing means 205 which pressurizes the tube 204 while rotating it, and an energizing means 500 for energizing the tube 204 toward the inside of the closed space 203.

Description

  The present invention relates to an image forming apparatus such as an ink jet printer having a plurality of tube pumps.

  In an image forming apparatus such as an ink jet printer, a technique of using a pump unit as means for transferring ink from an ink tank to a print head, and driving a plurality of pump units by a plurality of driving sources because of having a plurality of heads at that time It has been known. In addition, there are problems related to assembling for suppressing moisture evaporation from the tube of the pump unit and a problem that the number of parts increases and the installation space for a plurality of pump units increases. On the other hand, at least two pump units including a tube, a pressing means that presses the tube while rotating the tube, and a pump case in which one of the tube and the pressing means is opened in a recessed space are integrated, Each pump case of the two pump units has a configuration in which the recessed space is opposed and fixed via a seal member, and the recessed space in which the tube and the pressing means are accommodated is a substantially sealed space (for example, “ See Patent Document 1).

However, in the conventional technology for driving the pump unit, the pressure in the supply unit continues to rise when the pump is continuously driven. Therefore, on / off control of driving by a sensor or the like is necessary. Alternatively, there is a problem in that drive switching is necessary, which increases the number of parts, increases costs, and requires a control mechanism. Further, when the driving is continued due to a failure of a sensor or the like, the pressure continues to rise, and there is a risk of ink leakage, which causes a problem that the apparatus is seriously damaged.
The present invention solves the above-mentioned problems, and is capable of always driving without using an on-off control without using a sensor or the like by suppressing pressure rise, and can drive a plurality of pump units with a single drive source. An object of the present invention is to provide a possible tube pump and an image forming apparatus including the tube pump.

  The present invention provides a tube through which a liquid passes in a sealed space in a pump case, a pressing unit that presses the tube while rotating, and a biasing unit that biases the tube toward the inside of the sealed space. It is characterized by having.

  According to the present invention, when the internal pressure increases excessively by continuously driving the tube pump, the urging means is pushed back by the internal pressure to open the nip portion, and the ink is pushed back to the sub tank side to suppress excessive pressure. Therefore, it is possible to prevent the occurrence of a malfunction such as a device failure.

1 is a schematic view of an image forming apparatus to which an embodiment of the present invention can be applied. It is the schematic explaining the ink supply means used for one Embodiment of this invention. It is the schematic explaining the ink supply means used for one Embodiment of this invention. It is the schematic explaining the tube pump used for one Embodiment of this invention. It is the schematic explaining the tube pump used for one Embodiment of this invention. It is the schematic explaining the tube pump used for one Embodiment of this invention. It is the schematic explaining the tube pump used for one Embodiment of this invention. It is the schematic explaining the tube pump used for one Embodiment of this invention. It is the schematic explaining the tube pump used for one Embodiment of this invention. It is the schematic explaining the biasing means used for the 1st Embodiment of this invention. It is the schematic explaining the urging means used for the 2nd Embodiment of this invention. It is the schematic explaining the urging means used for the 3rd Embodiment of this invention. It is the schematic explaining the biasing means used for the 4th Embodiment of this invention. It is the schematic explaining the biasing means used for the 5th Embodiment of this invention. It is the schematic explaining the arrangement | positioning of the urging means used for the 1st thru | or 5th embodiment of this invention. It is the schematic explaining the relationship between the press range of the urging | biasing means used for the 1st thru | or 5th embodiment of this invention, and a pressure fluctuation. It is the schematic explaining the biasing means used for the 6th Embodiment of this invention. It is the schematic explaining the urging means used for the 7th Embodiment of this invention.

  FIG. 1 is a schematic configuration diagram of an ink jet printer which is an image forming apparatus to which an embodiment of the present invention can be applied. In the figure, the ink jet printer 1 has a recording head 34 in a carriage 33, and forms an image on a sheet having a necessary size by conveying a sheet P printed in the sub-scanning direction. The present invention can also be applied to a line ink jet printer having a head in the entire main scanning direction without using the carriage 33.

  FIG. 2 shows a schematic configuration of the ink supply means 30 that supplies ink to the recording head 34 of the inkjet printer 1. In this embodiment, yellow, magenta, cyan, and black inks are used, and each ink supply unit 30 is driven by each drive source to supply ink from the ink cartridge 31 of each color to the sub tank 35.

  FIG. 3 shows an example of the ink supply means 30 used in this embodiment. A sub-tank 35 is integrally provided on the recording head 34 mounted on the carriage 33 (see FIG. 1) via a filter 300. The ink cartridge 10 contains therein an ink bag 310 that can be deformed by external pressure. The ink bag 310 is connected to a hollow needle 223 provided in the tube pump 200 described later when the ink cartridge 10 is mounted on the apparatus main body. The tube pump 200 and the sub tank 35 constituting the ink supply means 30 are connected by the supply tube 36, and the ink 301 is supplied from the ink cartridge 10 to the sub tank 35 by driving the tube pump 200.

Next, the tube pump 200 will be described with reference to FIGS.
The tube pump 200 integrates two pump units 201A and 201B (simply referred to as pump unit 201 if not distinguished) by sandwiching a seal member 230 between the pump cases 202 of the pump units 201A and 201B. It is a thing. In the pump unit 201, a recessed space 203 is formed in a pump case 202 as a sealed space having an arcuate inner wall surface 203a. The recessed space 203 contains an elastic tube 204 through which ink passes, and pressing means 205 (see FIG. 8) for pressing the tube 204 while rotating. The pressing means 205 is driven in the other recessed space 206. A DC motor 207 which is a driving means is accommodated.

  As shown in FIGS. 7 to 9, the pressing means 205 includes a ring 211, a pressing roller (collar) 212, a gear 213 with an eccentric cam, a gear cover 214, and the like centering on a shaft 210 attached to the pump case 203. ing. The worm gear 215 attached to the output shaft of the DC motor 207 meshes with the gear 213 with the eccentric cam.

  As shown in FIG. 9, the pump unit 201 rotates the DC motor 207 forward and backward so that the eccentric cam cam 213 rotates eccentrically via the worm gear 215, so that the pressing roller 212 moves the elastic tube 204 to the inner wall surface. It rotates while pressing against 203a. Accordingly, the ink is supplied or sucked by pressing the elastic tube 204 against the inner wall surface 203a or releasing the pressure while the pressing roller 212 rotates in any of the arrow directions in FIG. One end of the elastic tube 204 is connected to the joint pipe 221 attached to the pump case 202, and the other end is connected to the joint pipe 222. A hollow needle 223 is connected to the joint pipe 221, and a supply tube 36 is connected to the joint pipe 222.

  As shown in FIG. 6, the tube pump 200 is formed of a packing, a rubber sheet, or the like having a higher gas barrier property than the elastic tube 204 between the joint surfaces of the pump cases 202 included in the two pump units 201 </ b> A and 201 </ b> B described above. The seal member 230 is sandwiched. Then, using the claw portion 231, a locking piece (not shown), a screw 233, and the like, the respective recessed spaces 203 in which the elastic tube 204 and the pressing means 205 are accommodated are fixed to face each other, and each recessed space of each pump case 202 is fixed. 203 is a substantially sealed space.

  Next, a first embodiment of the present invention will be described with reference to FIG. In the first embodiment, there is a biasing means 500 that biases a part of the outer periphery of the elastic tube 204 inward from the outside of the recessed space 203. The biasing means 500 includes a plate member 502 made of resin or metal that contacts a part of the elastic tube 204, and a compression coil spring 501 that biases the plate member 502 toward the elastic tube 204. The biasing means 500 is disposed in a recess space (not shown) formed in the pump case 202 so as to be continuous with the recess space 203.

  With this configuration, when the pressure in the ink supply means 30 increases excessively by continuously driving the tube pump 200, the urging means 500 is pushed back by the internal pressure to open the nip portion, and the ink is pushed back to the sub tank 35 side. Therefore, excessive pressure can be suppressed. Since the elastic tube 204 is normally pressed by the biasing means 500, a nip portion is formed and the internal pressure of the elastic tube 204 is maintained. In addition, although the structure which has the member urged | biased to the axis | shaft 210 side is known, the objective of this structure is suppressing the liquid feeding dispersion | variation, and is different from this invention. In addition, there is a concern about bending of the shaft because pressure is applied to the shaft. However, in the present invention, there is no problem because pressure is not applied to the shaft.

  FIG. 11 shows a second embodiment of the present invention. In the second embodiment, only the biasing means 503 that biases a part of the outer circumference of the elastic tube 204 from the outside to the inside of the recessed space 203 instead of the biasing means 500 is used. This embodiment is different from the above embodiment, and the other configurations are the same. The biasing means 503 includes a plate member 505 made of resin or metal that contacts a part of the elastic tube 204, and a compression coil spring 504 that biases the plate member 505 toward the elastic tube 204. One end of the plate member 505 is rotatably supported on the inner wall surface 203 a of the pump case 202. With this configuration, when the pressing means 205 rotates in the direction of the arrow in FIG. 11 and presses the elastic tube 204, the pressure increases on the downstream side of the elastic tube 204 in the pressing direction, so that the nip portion can be easily opened. Compared with the first embodiment, the effect of suppressing excessive pressure can be improved.

  FIG. 12 shows a third embodiment of the present invention. This third embodiment is the first only in that it uses a biasing means 506 that biases a part of the outer periphery of the elastic tube 204 inward from the outside of the recessed space 203 in place of the biasing means 500. This embodiment is different from the above embodiment, and the other configurations are the same. The urging means 506 is a leaf spring formed by bending a plate-like member having elasticity into a square shape, and both end portions thereof are arranged so as to face the recessed space 203 from the cutout portion of the inner wall surface 203a. With this configuration, the same effects as those of the first embodiment can be obtained, and the number of parts can be reduced to reduce the cost and simplify the configuration.

  FIG. 13 shows a fourth embodiment of the present invention. In the fourth embodiment, only the biasing means 507 that biases a part of the outer periphery of the elastic tube 204 inward from the outside of the recess space 203 in place of the biasing means 500 is used. This embodiment is different from the above embodiment, and the other configurations are the same. The biasing means 507 is a leaf spring formed by bending an elastic plate-like member into a U shape, and is arranged so that one free end thereof faces the recessed space 203 from the notch of the inner wall surface 203a. Yes. With this configuration, the same operational effects as those of the second embodiment can be obtained, and the number of parts can be reduced to reduce the cost and simplify the configuration.

  FIG. 14 shows a fifth embodiment of the present invention. In the fifth embodiment, only the biasing means 508 that biases a part of the outer periphery of the elastic tube 204 from the outside to the inside of the recessed space 203 instead of the biasing means 500 is used. This embodiment is different from the above embodiment, and the other configurations are the same. The biasing means 508 is a film-like member that is a flexible member, and is arranged so as to cover the entire arc-shaped portion of the elastic tube 204, and a part thereof is configured to be able to bulge from the cutout portion of the inner wall surface 203a. Yes. With this configuration, the same effects as those of the first embodiment can be obtained, the number of parts can be reduced, the cost can be reduced, and the configuration can be simplified. It can be prevented from being damaged.

  In the first to fifth embodiments described above, the urging means 500, 503, 506, 507, and 508 can be enhanced by disposing the biasing means 500, 503, 506, 507, and 508 at a position farthest from the entrance / exit of the elastic tube 204. This is because the curved portion 509 is formed in the vicinity of the entrance / exit of the elastic tube 204 as shown in FIG. 15, and the outward bulge due to the internal pressure is reduced.

  In the first to fifth embodiments described above, the pressing range of the elastic tube 204 by the biasing means 500, 503, 506, 507, and 508 may be longer than the pressing range of the elastic tube 204 by the pressing means 205. desirable. This is because the pressure fluctuation can be suppressed smaller in the case where the pressing range shown in FIG. 16B is long than in the case where the pressing range shown in FIG. 16A is short. Therefore, it is desirable that the pressing range of the elastic tube 204 by the biasing means 500, 503, 506, 507, and 508 be as long as possible.

  FIG. 17 shows a sixth embodiment of the present invention. For the above-described reason, it is preferable that the pressing range of the elastic tube 204 by the urging means is longer. Therefore, a plurality of urging means 500 shown in the first embodiment are used to cover the elastic tube 204. With this configuration, it is possible to suppress the pressure fluctuation as compared with the first embodiment, and to further prevent the occurrence of problems.

  FIG. 18 shows a seventh embodiment of the present invention. In the seventh embodiment, only the biasing means 510 that biases the entire elastic tube 204 inward from the outside of the recessed space 203 in place of the biasing means 500 is used in the first embodiment. The other configurations are the same. The urging unit 510 includes a resin or rubber packing 512 that contacts the entire surface of the elastic tube 204 from the paper surface direction, and a compression coil spring 511 that urges the packing 512 toward the elastic tube 204. With this configuration, the same effects as those of the sixth embodiment can be obtained, and the number of parts can be reduced to reduce the cost and simplify the configuration.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above, and is described in the claims unless specifically limited by the above description. Various modifications and changes can be made within the scope of the present invention.
The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention. .

1 Image forming device (inkjet printer)
200 Tube pump 201 Pump unit 202 Pump case 203 Sealed space (recessed space)
204 Elastic tube 205 Pressing means 500, 503, 506, 507, 508 Energizing means 501, 504 Compression coil spring

JP 2010-143158 A

Claims (11)

A tube provided in the sealed space in the pump case and through which the liquid passes;
A pressing means for pressing the tube while rotating;
A tube pump having urging means for urging the tube toward the inside of the sealed space. The tube pump according to claim 1, wherein
The tube pump according to claim 1, wherein the urging means urges a part of the tube from the outside to the inside of the sealed space. The tube pump according to claim 2, wherein
The tube pump according to claim 1, wherein the biasing means includes a coil spring. The tube pump according to claim 3,
A tube pump characterized in that a part of the urging means is rotatably supported by the pump case. The tube pump according to claim 2, wherein
The tube pump according to claim 1, wherein the biasing means includes a leaf spring. The tube pump according to claim 2, wherein
The tube pump according to claim 1, wherein the biasing means includes a flexible member. In the tube pump as described in any one of Claim 2 thru | or 6,
The tube pump according to claim 1, wherein the urging means is disposed at a position farthest from the entrance / exit of the tube. The tube pump according to claim 2, wherein
The tube pump according to claim 1, wherein the biasing unit biases the tube in a range longer than a pressing range of the tube by the pressing unit. The tube pump according to claim 2, wherein
A tube pump comprising a plurality of the urging means. The tube pump according to claim 1, wherein
The tube pump according to claim 1, wherein the urging means urges the entire tube from the outside to the inside of the sealed space.   An image forming apparatus comprising the tube pump according to claim 1.

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